WO1992013954A1 - BACILLUS THURINGIENSIS CRYIIIC(b) TOXIN GENE AND PROTEIN TOXIC TO COLEOPTERAN INSECTS - Google Patents

BACILLUS THURINGIENSIS CRYIIIC(b) TOXIN GENE AND PROTEIN TOXIC TO COLEOPTERAN INSECTS Download PDF

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WO1992013954A1
WO1992013954A1 PCT/US1992/000040 US9200040W WO9213954A1 WO 1992013954 A1 WO1992013954 A1 WO 1992013954A1 US 9200040 W US9200040 W US 9200040W WO 9213954 A1 WO9213954 A1 WO 9213954A1
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Prior art keywords
gene
protein
strain
coleopteran
seq
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PCT/US1992/000040
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French (fr)
Inventor
William P. Donovan
Mark J. Rupar
Annette C. Slaney
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Ecogen Inc.
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Application filed by Ecogen Inc. filed Critical Ecogen Inc.
Priority to JP4503832A priority Critical patent/JP2531913B2/en
Priority to AU11926/92A priority patent/AU649785B2/en
Publication of WO1992013954A1 publication Critical patent/WO1992013954A1/en

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    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07KPEPTIDES
    • C07K14/00Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof
    • C07K14/195Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from bacteria
    • C07K14/32Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from bacteria from Bacillus (G)
    • C07K14/325Bacillus thuringiensis crystal protein (delta-endotoxin)
    • AHUMAN NECESSITIES
    • A01AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01NPRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
    • A01N63/00Biocides, pest repellants or attractants, or plant growth regulators containing microorganisms, viruses, microbial fungi, animals or substances produced by, or obtained from, microorganisms, viruses, microbial fungi or animals, e.g. enzymes or fermentates
    • A01N63/50Isolated enzymes; Isolated proteins

Definitions

  • the present invention relates to an isolated Bacillus thuringiensis strain, to its novel toxin encoding gene and to the insecticidal crystal protein toxin made by the gene, as well as to insecticidal compositions containing the protein that are toxic to coleopteran insects.
  • Bacillus thuringiensis (hereinafter "B.t.") is a gram-positive soil bacterium that produces crystal
  • compositions including B. t. strains which produce insecticidal proteins have been commercially available and used as environmentally acceptable
  • the B. t. crystal protein is toxic in the insect only after ingestion. After ingestion, the alkaline pH and proteolytic enzymes in the insect mid-gut solubilize the crystal allowing the release of the toxic components.
  • B. t. strains are active against insects of the order Lepidoptera, i.e., caterpillar insects.
  • Other B. t. strains are insecticidally active against insects of the order Diptera, i.e., flies and mosquitoes, or against both lepidopteran and dipteran insects.
  • a few B. t. strains have been reported as producing crystal protein that is toxic to insects of the order Coleoptera, i.e., beetles. The first isolation of a coleopteran-toxic B. t.
  • B. t. var. tenebrionis is reported to be toxic to larvae of the coleopteran insects Agelastica alni (blue alder leaf beetle) and Leptinotarsa decemlineata (Colorado potato beetle).
  • B. t. tenebrionis makes an insecticidal crystal protein reported to be about 65-70 kilodaltons (kDa) (U.S. Patent 4,766,203; see also K. Bernhard, FEMS
  • a coleopteran-toxic strain designated B. t. var. san diego, is reported by C. Herrnstadt et al.,
  • Another new B. t. strain, designated EG2158, is reported by W.P. Donovan et al., in Mo 1. Gen. Gene t. , 214 , pp.365-372 (1988) and in U.S. Patent No. 5,024,837 issued June 18, 1991, to produce a 73 kDa crystal protein that is insecticidal to coleopteran insects.
  • the toxin-encoding gene from B. t. strain EG2158 was cloned and sequenced, and its sequence is identical to that reported by Sekar et al. (1987) for the cloned B. t. tenebrionis coleopteran toxin gene. This coleopteran toxin gene is referred to as the cry ⁇ IIA gene by H ⁇ fte et al., Microbiol . Rev. , 53 , pp.242-255 (1989).
  • coleopteran toxin plasmid transferred from B. t. strain EG2158 by conjugal plasmid transfer.
  • hybrid B. t. microorganism containing a plasmid from B. t. var. kurstaki with a lepidopteran toxin gene and a plasmid from B. t . tenebrionis with a coleopteran toxin gene.
  • the hybrid B. t. produces crystal proteins
  • European Patent Application Publication No. 0 318 143 published May 31, 1989, of Lubrizol Genetics, Inc. discloses the cloning, characterization and selective expression of the intact partially modified gene from B. t. tenebrionis, and the transfer of the cloned gene into a host microorganism rendering the microorganism able to produce a protein having toxicity to coleopteran insects.
  • Insect bioassay data for B. t. san diego reproduced from Herrnstadt et al., Bio/Technology, 4 , pp.305-308 (1986) discussed above, is summarized. The summary also includes data for B. t. tenebrionis from another source; B. t.
  • B. t. microorganism identified as B. t. PS86B1 which has insecticidal activity against the
  • B. t. strain PS86B1 is identified via serotyping as being serovar tolworthi .
  • European Patent Application No. 0 382 990 published August 22, 1990, of Plant Genetic Systems N.V., discloses two novel B. t. strains (btGSI208 and btGSI245) producing respective crystal proteins of 74 and 129 kDa that exhibit insecticidal activity against Colorado potato beetle larvae.
  • Diabrotica corn rootworm
  • Diabrotica virgifera western corn rootworm
  • the B. t. strain of the present invention contains a novel toxin gene that expresses protein toxin having quantifiable insecticidal activity against the Diabrotica insects, among other coleopteran insects.
  • One aspect of the present invention relates to a purified and isolated coleopteran toxin gene having a nucleotide base sequence coding for the amino acid
  • cry ⁇ IIC (b) gene SEQ ID NO:1
  • the cry ⁇ IIC(b) gene SEQ ID NO:1 has a coding region
  • the Cry ⁇ IIC(b) protein (SEQ ID NO: 2) has the amino acid sequence, as deduced from the nucleotide sequence of the cry ⁇ IIC(b) gene (SEQ ID NO:1) from nucleotide bases 144 to 2099 that is shown in Figure 1.
  • the protein exhibits insecticidal activity against insects of the order Coleoptera, in particular, Colorado potato beetle and insects of the genus Diabrotica .
  • Still another aspect of the present invention relates to a biologically pure culture of a B. t. bacterium
  • B. t. strain EG5144 is a wild-type B. t. strain that carries the cry ⁇ IIC(b) gene (SEQ ID NO:1) and produces the insecticidal Cry ⁇ IIC(b) protein (SEQ ID NO:1)
  • B. t. strain EG5145 is also a wild-type B. t.
  • Yet another aspect of this invention relates to insecticidal compositions containing, in combination with an agriculturally acceptable carrier, either the
  • the invention also includes a method of controlling coleopteran insects by applying to a host plant for such insects an insecticidally effective amount of the
  • Cry ⁇ IIC(b) protein SEQ ID NO: 2
  • the method is applicable to a variety of coleopteran insects, such as the Colorado potato beetle, Japanese beetle larvae (white grubs), Mexican bean beetle and corn rootworm.
  • Still another aspect of the present invention relates to a recombinant plasmid containing the cry ⁇ IIC(b) gene (SEQ ID NO:l), a biologically pure culture of a bacterium transformed with such recombinant plasmid, the bacterium preferably being B. t. , such as B. t. strain EG7237
  • Example 6 described in Example 6, as well as a plant transformed with the cry ⁇ IIC(b) gene.
  • Figure 1 comprises Figures 1-1 through 1-3 and shows the nucleotide base sequence of the cry ⁇ IIC (b) gene (SEQ ID NO:1) and the deduced amino acid sequence of the
  • Cry ⁇ IIC(b) protein SEQ ID NO: 2.
  • the putative ribosome binding site (RBS) is indicated. Restriction sites for Sspl and ffindIII are also indicated.
  • Figure 2 is a photograph of an ethidium bromide stained agarose gel containing size fractionated native plasmids of B. t. strains EG5144 (lane 1), EG4961 (lane 2), EG2838 (lane 3) and EG2158 (lane 4).
  • the numbers to the left of Figure 2 indicate the approximate sizes, in megadaltons (MDa), of the plasmids of B. t. strain EG5144.
  • Figure 3 is a photograph of an autoradiogram made by transferring size fractionated DNA fragments from an agarose gel to a nitrocellulose filter, hybridizing the filter with a radioactively labeled 2.4 kilobases (kb) cryIIIB probe, and exposing the filter to X-ray film.
  • the agarose gel contained size fractionated total DNA
  • the lane labeled "stnd" is a size standard.
  • Figure 4 is a photograph of a Coomassie stained sodium dodecyl sulfate (“SDS") polyacrylamide gel showing crystal proteins solubilized from B. t. strains EG5144 (lane 1), EG4961 (lane 2) , EG2158 (lane 3) and EG2838 (lane 4).
  • the numbers to the left of Figure 4 indicate the approximate sizes in kDa of the crystal proteins produced by B. t. strain EG5144.
  • Lane 5 contains protein molecular size standards.
  • Figure 5 shows a restriction map of plasmid pEG271.
  • the location and orientation of the cry ⁇ IIC(b) gene (SEQ ID NO:1) is indicated by the arrow.
  • Plasmid pEG271 is functional in Escherichia coli (E. coli) , since it contains E. coli plasmid pUC18 (Ap r ), indicated by the segment marked pUC18.
  • a one kilobase scale marker is also illustrated.
  • Figure 6 aligned with and based on the same scale as Figure 5, shows a restriction map of plasmid pEG272.
  • the location and orientation of the cry ⁇ IIC(b) gene (SEQ ID NO:1) is indicated by the arrow shown in Figure 5.
  • Plasmid pEG272 is derived from plasmid pEG271 ( Figure 5) and contains the Bacillus plasmid pNN101 (Cm r Tc r ), indicated by the segment marked pNN101 and is incorporated into the SphI site of pEG271; this plasmid is functional in B. t. Abbreviations are the same as those for Figure 5.
  • Figure 7 is a photograph of a Coomassie stained SDS-polyacrylamide gel. The gel shows protein bands
  • Lane 2 contains a protein size standard and the numbers on either side of lanes 1 and 3 indicate approximate sizes, in kDa, of the crystal proteins produced by these strains.
  • cry ⁇ IIC (b) gene SEQ ID NO:1
  • coleopteran-toxic Cry ⁇ IIC(b) crystal protein SEQ ID NO: 2
  • characterization of the new B. t. strain EG5144 which produces the Cry ⁇ IIC(b) protein are described at length in Examples 1-7.
  • the utility of B. t. strain EG5144 and of the Cry ⁇ IIC(b) crystal protein (SEQ ID NO:2) in insecticidal compositions and methods is also illustrated in Examples 8-11.
  • cry ⁇ IIC(b) gene (SEQ ID NO:1), has the nucleotide base sequence shown in Figure 1.
  • the coding region of the cry ⁇ IIC(b) gene extends from nucleotide base position 144 to position 2099 shown in Figure 1.
  • cry ⁇ IIC(b) gene coding region A comparison of the nucleotide base sequence of the cry ⁇ IIC(b) gene coding region with the corresponding coding region of the prior art cryIIIA gene indicates significant differences between the two genes.
  • the cry ⁇ IIC(b) gene (SEQ ID NO:1) is only 76% homologous
  • cryIIIC(b) gene SEQ ID NO:1 is 96% homologous (positionally identical) with the cryIIIB gene.
  • Cry ⁇ IIC(b) protein that is encoded by the cry ⁇ IIC(b) gene (SEQ ID NO:1), has the amino acid sequence (SEQ ID NO:2) shown in Figure 1.
  • references to the Cry ⁇ IIC(b) "protein” are synonymous with its description as a “crystal protein”, “protein toxin”, “insecticidal protein” or the like, unless the context indicates otherwise.
  • the size of the Cry ⁇ IIC(b) protein (SEQ ID NO:2), as deduced from the DNA sequence of the cry ⁇ IIC(b) gene (SEQ ID NO:1), is 74,265 Daltons (Da).
  • the size of the CryIIIB protein, as deduced from the sequence of the cryIIIB gene, is 74,237 Da.
  • the prior art CryIIIA protein, encoded by the cryIIIA gene has a deduced size of 73,116 Da.
  • Cry ⁇ IIC(b) protein (SEQ ID NO: 2) has been shown to be a different protein than the CryIIIB protein, based on its significantly improved insecticidal activity compared to the CryIIIB protein with respect to insects of the order Coleoptera and in particular, insects of the genus
  • Diabrotica The Cry ⁇ IIC(b) protein (SEQ ID NO:2), unlike the CryIIIB protein, exhibits quantifiable insecticidal activity against corn rootworm larvae.
  • the present invention is intended to cover mutants and recombinant or genetically engineered derivatives, e.g., truncated versions, of the cry ⁇ IIC(b) gene (SEQ ID NO:1) that yield a protein with insecticidal properties essentially the same as those of the Cry ⁇ IIC(b) protein (SEQ ID NO:2).
  • cry ⁇ IIC(b) gene (SEQ ID NO:1) is also useful as a DNA hybridization probe, for discovering similar or closely related cryIII-type genes in other B. t. strains.
  • the cry ⁇ IIC(b) gene (SEQ ID NO:1), or portions or
  • hybridization probe e.g., with a radioactive label
  • the labeled DNA hybridization probe may then be used in the manner described in the Examples.
  • cry ⁇ IIC(b) gene (SEQ ID NO:1) and the
  • B. t. strain EG5144 a novel B. t. isolate.
  • the characteristics of B.t. strain EG5144 are more fully described in the Examples. Comparison of the plasmid arrays and other strain characteristics of B. t. strain EG5144 with those of the recently discovered B. t. strains EG2838 and EG4961 and those of the prior art B. t. strain EG2158 and B. t. var. tenebrionis (or the equivalent, B. t. var. san diego) demonstrates that each of these coleopteran-toxic B. t. strains is distinctly
  • the plasmid array of B. t. strain EG5145 is similar to that of B. t. strain EG5144, and B. t. strain EG5145 exhibits the same insecticidal activity against coleopteran insects, e.g., Japanese beetle larvae, as that of B. t . strain EG5144 (see Example 11).
  • cry I ⁇ IC(b) gene may be introduced into a variety of microorganism hosts, using procedures well known to those skilled in the art for transforming suitable hosts under conditions which allow for stable maintenance and expression of the cloned cry ⁇ IIC(b) gene.
  • Suitable hosts that allow the cry ⁇ IIC (b) gene (SEQ ID NO:1) to be expressed and the Cry ⁇ IIC(b) protein (SEQ ID NO: 2) to be produced include Bacillus thuringiensis and other Bacillus species such as B. subtilis or B.
  • cry ⁇ IIC (b) gene SEQ ID NO:1
  • SEQ ID NO:1 can also contain other toxin genes present in the same microorganism and that these genes could concurrently produce insecticidal crystal proteins different from the CryIIIC(b) protein.
  • the Bacillus strains described in this disclosure may be cultured using conventional growth media and standard fermentation techniques.
  • the B. t. strains harboring the cry ⁇ IIC(b) gene (SEQ ID NO:1) may be fermented, as
  • CryIIIC(b) crystal protein SEQ ID NO: 2
  • fermentation is typically continued through the sporulation stage when the CryIIIC (b) crystal protein is formed along with spores.
  • the B. t. fermentation culture is then typically harvested by centrifugation, filtration or the like to separate fermentation culture solids, containing the CryIIIC(b) crystal protein, from the aqueous broth portion of the culture.
  • the B. t. strains exemplified in this disclosure are sporulating varieties (spore forming or sporogenous strains) but the cry ⁇ IIC(b) gene (SEQ ID NO:1) also has utility in asporogenous Bacillus strains, i.e., strains that produced the crystal protein without production of spores. It should be understood that references to
  • “fermentation cultures” of B. t. strains in this disclosure are intended to cover sporulated B. t. cultures, i.e., B. t. cultures containing the CryIIIC(b) crystal protein and spores, and sporogenous Bacillus strains that have produced crystal protein during the vegetative stage, as well as asporogenous Bacillus strains containing the cryIIIC(b) gene (SEQ ID NO:1) in which the culture has reached the growth stage where crystal protein is actually produced.
  • the separated fermentation solids are primarily
  • CryIIIC(b) crystal protein (SEQ ID NO:2) and B. t. spores, along with some cell debris, some intact cells, and residual fermentation medium solids.
  • the crystal protein may be separated from the other recovered solids via conventional methods, e.g., sucrose density gradient fractionation.
  • Highly purified CryIIIC(b) protein (SEQ ID NO: 2) may be obtained by solubilizing the recovered crystal protein and then precipitating the protein from solution.
  • the CryIIIC(b) protein (SEQ ID NO: 2), as noted earlier, is a potent insecticidal compound against
  • coleopteran insects such as the Colorado potato beetle, Japanese beetle larvae (white grubs), Mexican bean beetle and the like.
  • the CryIIIC(b) protein (SEQ ID NO: 2), in contrast to the CryIIIA and CryIIIB proteins, exhibits measurable insecticidal activity against Diabrotica insects, e.g., corn rootworms, which have been relatively unaffected by other coleopteran-toxic B. t. crystal
  • the CryIIIC(b) protein (SEQ ID NO: 2) may be utilized as the active ingredient in insecticidal
  • formulations or compositions typically contain
  • the CryIIIC(b) protein may be employed in insecticidal formulations in isolated or purified form, e.g., as the crystal protein itself.
  • the CryIIIC(b) protein may be present in the recovered fermentation solids, obtained from culturing of a Bacillus strain, e.g., Bacillus thuringiensis , or other microorganism host carrying the cry ⁇ IIC(b) gene (SEQ ID NO:1) and capable of producing the CryIIIC(b) protein.
  • Bacillus hosts include B. t. strain EG5144 and genetically improved B. t. strains derived from B. t. strain EG5144. The latter B. t.
  • strains may be obtained via plasmid curing and/or conjugation techniques and contain the native cryIIIC(b) gene-containing plasmid from B. t. strain EG5144. Genetically engineered or transformed B. t. strains or other host microorganisms containing a
  • EG7237 which contains the cloned cry ⁇ IIC(b) gene (SEQ ID NO:1) on a recombinant plasmid.
  • the recovered fermentation solids contain primarily the crystal protein and (if a sporulating B. t. host is employed) spores; cell debris and residual fermentation medium solids may also be present.
  • fermentation solids containing the CryIIIC(b) protein may be dried, if desired, prior to incorporation in the insecticidal formulation.
  • compositions or compositions of this invention containing the insecticidal CryIIIC (b) protein (SEQ ID NO: 2) as the active component are applied at an insecticidal CryIIIC (b) protein (SEQ ID NO: 2) as the active component.
  • insecticidally effective amount which will vary depending on such factors as, for example, the specific coleopteran insects to be controlled, the specific plant or crop to be treated and the method of applying the insecticidally active compositions.
  • An insecticidally effective amount of the insecticide formulation is employed in the insect control method of this invention.
  • insecticide compositions are made by formulating the insecticidally active component with the desired agriculturally acceptable carrier.
  • the formulated insecticide compositions are made by formulating the insecticidally active component with the desired agriculturally acceptable carrier. The formulated
  • compositions may be in the form of a dust or granular material, or a suspension in oil (vegetable or mineral) or water or oil/water emulsions, or as a wettable powder, or in combination with any other carrier material suitable for agricultural application.
  • Suitable agricultural carriers can be solid or liquid and are well known in the art.
  • the term "agriculturally acceptable carrier” covers all adjuvants, e.g., inert components, dispersants, surfactants, tackifiers, binders, etc. that are ordinarily used in insecticide formulation technology; these are well known to those skilled in insecticide formulation.
  • the formulations containing the CryIIIC(b) protein (SEQ ID NO: 2) and one or more solid or liquid adjuvants are prepared in known manners, e.g., by homogeneously mixing, blending and/or grinding the insecticidally active CryIIIC (b) protein component With suitable adjuvants using conventional formulation techniques.
  • insecticidal compositions of this invention are applied to the environment of the target coleopteran insect, typically onto the foliage of the plant or crop to be protected, by conventional methods, preferably by spraying.
  • Other application techniques e.g., dusting, sprinkling, soaking, soil injection, seed coating,
  • seedling coating or spraying, or the like are also feasible and may be required for insects that cause root or stalk infestation. These application procedures are well known in the art.
  • cryIIIC(b) gene (SEQ ID NO:1) or its functional equivalent, hereinafter sometimes referred to as the
  • cryIIIC (b) gene can be introduced into a wide variety of microorganism hosts.
  • Expression of the cryIIIC (b) gene results in the production of insecticidal CryIIIC(b) crystal protein toxin (SEQ ID NO:2).
  • Suitable hosts include B. t. and other species of Bacillus, such as B. ⁇ ubtilis or B. megaterium, for example.
  • Plant- colonizing or root-colonizing microorganisms may also be employed as the host for the cryIIIC(b) gene (SEQ ID NO:
  • cryIIIC(b) gene SEQ ID NO:1
  • Various procedures well known to those skilled in the art are available for introducing the cryIIIC(b) gene (SEQ ID NO:1) into the microorganism host under conditions which allow for stable maintenance and expression of the gene in the resulting transformants.
  • the transformants i.e., host microorganisms that harbor a cloned gene in a recombinant plasmid
  • the transformants then can be tested for
  • Characteristics of particular interest in selecting a host cell for purposes of production include ease of introducing the gene into the host, availability of expression systems, efficiency of expression, stability of the CryIIIC(b) insecticidal protein in the host, and the presence of auxiliary genetic capabilities.
  • the cellular host containing the insecticidal cry ⁇ IIC(b) gene may be grown in any convenient nutrient medium, where expression of the cry ⁇ IIC (b) gene is obtained and CryIIIC(b) protein (SEQ ID NO:2) produced, typically to sporulation.
  • the sporulated cells containing the crystal protein may then be harvested in accordance with
  • cry ⁇ IIC(b) gene (SEQ ID NO:1) may also be expressed as SEQ ID NO:1
  • cry ⁇ IIC (b) gene SEQ ID NO:1
  • Genetic engineering of plants with the cry ⁇ IIC (b) gene may be accomplished by introducing the desired DNA containing the gene into plant tissues or cells, using DNA molecules of a variety of forms and origins that are well known to those skilled in plant genetic engineering.
  • An example of a technique for introducing DNA into plant tissue is disclosed in European Patent Application Publication No. 0 289 479, published November 2, 1988, of Monsanto Company.
  • CryIIIC(b) protein may be delivered into the plant cells or tissues directly by infectious plasmids, such as Ti, the plasmid from Agrobacterium tumefaciens, viruses or microorganisms like A. tumefaciens, by the use of lysosomes or liposomes, by microinjection by mechanical methods and by other techniques familiar to those skilled in plant genetic engineering.
  • infectious plasmids such as Ti
  • the plasmid from Agrobacterium tumefaciens viruses or microorganisms like A. tumefaciens
  • lysosomes or liposomes by microinjection by mechanical methods and by other techniques familiar to those skilled in plant genetic engineering.
  • nucleotide base sequence SEQ ID NO:1
  • the various amino acids forming the protein encoded by the gene usually may be determined by more than one codon, as is well known to those skilled in the art.
  • there may be some variations or truncation in the coding regions of the cry ⁇ IIC(b) nucleotide base sequence which allow expression of the gene and production of functionally equivalent forms of the CryIIIC(b) insecticidal protein.
  • the novel B. t. strain EG5144 was isolated following the procedure described in Example 1. The procedures described in Example 1 were also used to isolate the novel B. t. strain EG5145.
  • Crop dust samples were obtained from various sources throughout the U.S. and abroad, typically grain storage facilities. The crop dust samples were treated by
  • the filter was placed colony side up on an agar medium containing 0.5% (w/v) glucose.
  • the transferred colonies were then allowed to grow on the agar-glucose medium for 5 hours at 30°C.
  • Use of 0.5% glucose in the agar medium and the 5-hour, 30°C growth cycle were critical for assuring that the B. t. colonies were in a vegetative state and thus susceptible to lysis.
  • a cloned coleopteran toxin gene was used as a
  • the 2.9 kb HindIII cryIIIA DNA fragment containing the entire cryIIIA gene, was radioactively labeled with [alpha- P32 ]-dATP and Klenow enzyme, by standard methods.
  • the nitrocellulose filters containing the DNA from each lysed colony were incubated at 65°C for 16 hours in a buffered solution that contained the radioactively labeled 2.9 kb HindIII cry ⁇ IIA DNA probe to hybridize the DNA from the colonies with the DNA from the radioactively labeled cry ⁇ IIA probe.
  • the 65°C hybridization temperature was used to assure that the cryIII A DNA probe would hybridize only to DNA from colonies that contained a gene that was similar to the cry ⁇ IIA DNA probe.
  • cryI-type genes encode lepidopteran-toxic, coleopteran-nontoxic crystal proteins with molecular masses of approximately 130 kDa.
  • Computer- assisted comparisons of the sequence of the cryIIIA gene with the sequence of several cryI-type genes revealed that the 3'-end of the cryIIIA gene was partially homologous with portion of the cryI-type genes. This finding
  • cry ⁇ IIA 3'-end of the cry ⁇ IIA gene was causing the 2.9 kb cry ⁇ IIA probe to hybridize to B. t. colonies containing cryJ-type genes.
  • HindIII-XbaI fragment was purified that contained the cryIIIA gene minus its 3'-end.
  • the 2.0 kb HindIII-XbaI fragment contains the 3'-truncated cryIIIA gene. When the 2.0 kb fragment was used in repeated colony hybridization experiments, it did not hybridize to cryI gene-containing B. t. colonies.
  • strain EG2838 which has been deposited with the NRRL under Accession No. NRRL B-18603.
  • B. t. strain EG2838 was found to be insecticidally active against coleopteran insects, notably, the Colorado potato beetle. B. t. strain EG2838 did not have
  • cryIIIB gene A gene, designated the cryIIIB gene, was isolated from B. t. strain EG2838, and its nucleotide base sequence determined.
  • the cryIIIB gene encoded a crystal protein, designated the CryIIIB protein, containing 651 amino acids having a deduced size of 74,237 Daltons.
  • the size of the prior art CryIIIA protein had previously been deduced to be 73,116 Daltons (644 amino acids).
  • the cryIIIB gene is 75% homologous with the cryIIIA gene, and the CryIIIB protein is 68% homologous with the CryIIIA protein.
  • cryIIIB probe obtained from B. t. strain EG2838.
  • the cryIIIB probe was radioactively labeled using the procedure set forth above with respect to the radioactively labeled cryIIIA probe.
  • radioactively labeled cryIIIB probe consisted of a 2.4 kb Sspl restriction fragment of DNA from B. t. strain EG2838. The fragment contains the complete protein coding region for the coleopteran toxin cryIIIB gene of B. t. strain EG2838.
  • the B. t. strains of the present invention designated B. t. strains EG5144 and EG5145, were isolated from a crop dust sample via B. t. colonies that specifically hybridized to the cryIIIB probe.
  • B. t. strain EG5144 To characterize B. t. strain EG5144, several studies were conducted. One series of studies was performed to characterize its flagellar serotype. Additional studies were conducted to determine the sizes of the native plasmids in B. t. strain EG5144 and to ascertain which plasmids contained genes that encoded coleopteran-active insecticidal crystal proteins. DNA blot analysis was thereafter performed using size fractionated total DNA restriction fragments from B. t. strain EG5144, compared with similarly-processed total DNA from other B. t. strains containing cry III-type toxin genes, to demonstrate that B. t. strain EG5144 contains a unique coleopteran-active toxin gene. In addition, B. t. strain EG5144 was evaluated further by characterizing the crystal proteins it produces and by measuring the insecticidal activity associated with B. t. strain EG5144 and its crystal proteins. Examples 2 through 7 are directed to the procedures for
  • Example 2 characterizing B. t. strain EG5144 and its unique cry ⁇ II- type gene, and Examples 8 through 11 are directed to the insecticidal activity of B. t. strain EG5144 and of B. t. strain EG7237, containing the cry ⁇ IIC(b) gene (SEQ ID NO:l) of this invention.
  • Example 2
  • Flagellar serotyping studies were carried out with B. t. strain EG5144, using an antibody mediated cell agglutinization assay (Craigie et al., J. Immunol . , 21 , pp.417-511 (1936)).
  • Flagellar antibody reagents were prepared using purified flagella from B. t. var. kurstaki, morrisoni and tolworthi type-strains and from the novel coleopteran-active B. t. strain EG4961.
  • the other coleopteran-active B.t. strains included B.t. var. tenebrionis, B.t. var. san diego, B.t. strain EG2158 (all containing the cryIIIA gene); B.t. strain EG2838 (containing the cryIIIB gene); and B.t. strain EG4961 (containing a novel coleopteran toxin-encoding gene designated as the cry ⁇ IIC(a) gene).
  • the B.t. flagellar type-strains were B.t. var.
  • israeltaki (HD-1, serotype 3ab), B.t. var. morrisoni (HD-12, serotype 8ab) and B.t. var. tolworthi (HD-13, serotype 9).
  • B. t. var. kurstaki (HD-1) + - - - B. t. var. morrisoni (HD-12) + - B. t. var. tolworthi (HD-13) - - + -
  • Table 1 show that cells of B. t. strain EG5144 gave a negative reaction with B. t. type-strain kurstaki , morrisoni and tolworthi flagella antibody reagents.
  • B. t. strain EG5144 cells also gave a negative reaction with flagellar reagent from B. t. strain EG4961, a novel coleopteran-active strain that has been discovered to exhibit Diabrotica toxicity.
  • B. t. strain EG5144 is not a kurstaki, morrisoni or tolworthi-type B. t. strain.
  • B. t. strain EG5144 which is yet not known, is apparently different from that of B. t. strain EG4961, which has been serotyped as serovar kumamotoensis (serotype 18).
  • Both B. t. strain EG5144 and B. t. strain EG4961 appear to have flagellar serotypes that are different from those of other coleopteran-toxic B. t. strains reported in the literature.
  • B. t. strains may be characterized by fractionating their plasmids according to size by the well-known
  • This procedure involves lysing B. t. cells with lysozyme and SDS,
  • Plasmides electrophoresing plasmids from the lysate through an agarose gel and staining the gel with ethidium bromide to visualize the plasmids. Larger plasmids, which move more slowly through the gel, appear at the top of the gel and smaller plasmids appear toward the bottom of the gel.
  • B.t. strain EG5144 contains native plasmids of approximately 145, 92, 12, 10 and 5.5 MDa, as indicated by the white horizontal bands. Plasmid sizes were estimated by comparison to plasmids of known sizes (not shown). Although not shown on Figure 2, B. t. strain EG5145 contains native plasmids of approximately 145, 92, 12 and 5.5 MDa. The cryptic 10 MDa plasmid found in B. t. strain EG5144 is not present in B. t. strain EG5145.
  • Figure 2 further shows that the coleopteran-toxic B. t. strain EG4961 contains native plasmids of about 150, 95, 70, 50, 5 and 1.5 MDa and that the coleopteran-toxic B. t. strain EG2838 contains native plasmids of about 100, 90 and 37 MDa.
  • Figure 2 also shows that the coleopteran- toxic B. t. strain EG2158 contains native plasmids of about 150, 105, 88, 72, and 35 MDa.
  • strain EG2158 may not be visible in the photograph, although they are visible in the actual gel.
  • Figure 2 demonstrates that the sizes of the native plasmids of B. t. strain EG5144 are different from the sizes of the native plasmids of B. t. strains EG2158, EG2838 and EG4961.
  • B. t. strain EG5144 is
  • B. t. strain EG5145 appears distinct from the coleopteran-toxic B. t. strains noted above based on plasmid array studies.
  • the plasmids shown in Figure 2 were transferred by blotting from the agarose gel to a nitrocellulose filter using the blot techniques of Southern, J.Molec.Biol . , 98 , pp.503-517 (1975), and the filter was hybridized as described above with the radioactively labeled 2.4 kb cryIIIB DNA probe. After hybridization, the filter was exposed to X-ray film. Examination of the X-ray film confirmed that the cryIIIB probe specifically hybridized to the 92 MDa plasmid of B. t. strain EG5144. This result demonstrates that the 92 MDa plasmid of B. t.
  • strain EG5144 contains a DNA sequence that is at least partly homologous to the cry ⁇ IIB gene and confirms that the 92 MDa plasmid contains a cryIII-type gene.
  • the X-ray film also showed that the cry ⁇ IIB probe hybridized, as expected, to the 95 MDa plasmid of B. t. strain EG4961 and to. the 100 MDa plasmid of B. t. strain EG2838, and to the 88 MDa plasmid of B. t. strain EG2158.
  • the 88 MDa plasmid of B. t. strain EG2158 has been previously shown to contain the
  • coleopteran-toxin cry ⁇ IIA gene see Donovan et al., Mol . Gen. Genet. , 214 , pp.365-372 (1988)).
  • the inventors have previously determined that the 100 MDa plasmid of B. t. strain EG2838 contains the coleopteran toxin cryIIIB gene and that the 95 MDa plasmid of B. t. strain EG4961 contains the novel coleopteran toxin cry ⁇ IIC(a) gene.
  • Both chromosomal and plasmid DNA (total DNA) from B. t. strain EG5144 were extracted and digested with separate restriction enzymes, SspI , HindIII and EcoRI.
  • the digested DNA was size fractionated by electrophoresis through an agarose gel, and the fragments were then visualized by staining with ethidium bromide.
  • strains EG2158, EG2838 and EG4961 was processed in an identical manner. Examination of the resultant stained agarose gel showed that restriction digestions of total DNA from these B. t. strains with each of SspI , HindIII and EcoRI yield hundreds of DNA fragments of various sizes.
  • the size fractionated DNA restriction fragments were transferred by blotting from the agarose gel to a
  • FIG. 3 is a photograph of the autoradiogram where the numbers to the left indicate the size, in kb, of the DNA fragments of B.t. strain EG5144 that hybridized to the cryIIIB probe. These sizes were determined by comparison with the lane labeled "stnd" which contained phage lambda DNA digested with HindIII and radioactively labelled as size markers. Lanes in Figure 3 marked EG2158, EG5144, EG2838 and EG4961 contain size fractionated DNA fragments from these respective B. t.
  • strains obtained by digestion with the restriction enzyme designated above the individual lanes.
  • cryIIIB-hybridizing SspI restriction fragment for B. t. strain EG5144 is 3.4 kb, and this is unlike the corresponding Sspl restriction fragments for the other three B. t. strains: 2.8 kb for B. t. strain EG2158; 2.4 kb for B. t. strain EG2838; and 4.5 and 6.0 kb for B. t. strain EG4961. Similar differences are apparent for the DNA restriction fragments obtained using HindIII and EcoRI. These restriction pattern results suggest that B. t. strain EG5144 contains a cry III-type gene that is
  • cryIIIA, cryIIIB and cry ⁇ IIC(a) genes of B. t. strains EG2158, EG2838 and EG4961 respectively.
  • the cryIII-type gene of B. t. strain EG5144 has been designated cryIIIC(b; (SEQ ID NO:1) by the inventors.
  • Total DNA from B. t. strain EG5144 and B. t. strain EG5145 was extracted and digested with six separate restriction enzymes (HindIII, EcoRI , AccI, DraI , SspI , Xbal) , and size fractionated by electrophoresis on an agarose gel. The size fractionated DNA restriction fragments were then transferred by blotting to a
  • B. t. strain EG5144 was grown in DSMG sporulation medium at room temperature (about 21-25°C) until
  • the DSMG medium is 0.4% (w/v) Difco nutrient broth, 25 mM K 2 HPO 4 , 25 mM KH 2 PO 4 , 0.5 mM Ca(NO 3 ) 2 , 0.5 mM MgSO 4 , 10 ⁇ M FeSO 4 , 10 ⁇ M. MnCl 2 and 0.5% (w/v) glucose.
  • the sporulated culture of B. t. strain EG5144 was observed microscopically to contain free floating, irregularly shaped crystals in addition to B. t. spores.
  • B. t. crystals are usually composed of proteins that may be toxic to specific insects. The appearance of the crystals of B.
  • t. strain EG5144 differed from the flat, rectangular (or rhomboidal) crystals of B. t. strain EG2158, but partially resembled some of the irregularly shaped crystals of B. t. strains EG2838 and EG4961.
  • TETX containing 10 mM Tris HC1 pH 7.5, ImM EDTA and 0.005% (w/v) Triton ® x-100
  • the washed crystals were specifically solubilized from 250 ⁇ g centrifuged
  • Figure 4 shows the results of this protein size fractionation analysis where the numbers to the left indicate the size, in kDa, of the crystal proteins
  • B. t. strain EG5144 synthesized by B. t. strain EG5144. As shown in lane 1, a major protein of approximately 70 kDa and a minor protein of approximately 30 kDa were solubilized from centrifuged fermentation solids containing B. t. strain EG5144 spores and crystals. The approximately 70 kDa protein of B. t. strain EG5144 appears similar in size to the approximately 70 kDa coleopteran-toxic crystal proteins of B. t. strains EG4961 (lane 2), EG2158 (lane 3) and to the approximately 74 kDa coleopteran-toxic crystal protein of B. t. strain EG2838 (lane 4).
  • the coleopteran-toxic crystal proteins of B. t. strains EG4961, EG2158 and EG2838 are each different.
  • the CryIIIC(a) protein of B. t. strain EG4961 is coded by the cry ⁇ IIC(a) gene and has a deduced size of 74,393 Da.
  • the CryIIIA protein of B. t. strain EG2158 is coded by the cryIIIA gene and has a deduced size of 73,116 Da.
  • the CryIIIB protein of B. t. strain EG2838 is coded by the cryIIIB gene and has a deduced size of 74,237 Da.
  • the coleopteran-toxic crystal protein of B. t. strain EG4961 is coded by the cry ⁇ IIC(a) gene and has a deduced size of 74,393 Da.
  • the CryIIIA protein of B. t. strain EG2158 is coded by the cryIIIA gene and has
  • EG5144 produced by the novel cryIIIC(b) gene is clearly different from the CryIIIA, CryIIIB and
  • the minor crystal protein of approximately 30 kDa that is produced by B. t. strain EG5144 is roughly similar in size to small crystal proteins produced by B. t. strains EG4961, EG2158 and EG2838.
  • the approximately 30 kDa minor proteins of B. t. strains EG2158, EG2838 and EG4961 appear to be related to each other and none has been found to exhibit measurable insecticidal activity towards
  • coleopteran insects There is no reason to believe that the approximately 30 kDa protein of B. t. strain EG5144 possesses insecticidal activity against coleopteran insects.
  • Example 6 The procedures set forth in Example 6 describe the determination of the nucleotide base sequence of the cry ⁇ IIC(b) gene (SEQ ID NO:1).
  • a plasmid library of B. t. strain EG5144 was constructed by ligating size- selected DNA EcoRI-XbaI restriction fragments from B. t. strain EG5144 into the well-known E. coli vector pUC18. This procedure involved first obtaining total DNA from B. t. strain EG5144 by cell lysis followed by DNA spooling, then double digesting the total DNA with both EcoRI and XbaI restriction enzymes, electrophoresing the digested DNA through an agarose gel, excising a gel slice
  • the plasmid library was then transformed into E. coli cells, a host organism lacking the gene of interest, as follows. After ligation, the DNA mixture was incubated with an ampicillin sensitive E. coli host strain, E. coli strain DH5 ⁇ , that had been treated with CaCl 2 to allow the cells to take up the DNA. E. coli, specifically strain DH5 ⁇ , was used as the host strain because these cells are easily transformed with recombinant plasmids and because E. coli strain DH5 ⁇ does not naturally contain genes for B. t. crystal proteins. Since pUC18 confers resistance to ampicillin, all host cells acquiring a recombinant plasmid would become ampicillin resistant. After exposure to the recombinant plasmids, the E. coli host cells were spread on agar medium that contained ampicillin. After
  • the radioactively labeled 2.4 kb cry ⁇ IIB gene was then used as a DNA probe under conditions that permitted the probe to bind specifically to those transformed host colonies that contained the 7.0 kb EcoRI-XbaI fragment of DNA from B. t. strain EG5144.
  • One cryIIIB-hybridizing colony, designated E. coli strain EG7236 was studied further.
  • E. coli strain EG7236 contained a recombinant plasmid, designated pEG271, which consisted of pUC18 plus the inserted EcoRI-XbaI
  • the cryIIIB probe specifically hybridized to the 7.0 kb DNA fragment insert in pEG271.
  • a restriction map of pEG271 is shown in Figure 5.
  • the 7.0 kb fragment of pEG271 contained HindIII fragments of 2.4 kb and 3.8 kb, and a BamHI-Xbal fragment of 4.0 kb that specifically hybridized with the cryIIIB probe.
  • the 2.4 kb HindIII fragment was subcloned into the DNA sequencing vector M13mp18.
  • the 4.0 kb BamHI -XbaI fragment was subcloned into the DNA sequencing vectors M13mp18 and M13mp19.
  • nucleotide base sequence of a substantial part of each subcloned DNA fragment was determined using the standard Sanger dideoxy method. For each subcloned fragment, both DNA strands were sequenced by using
  • cryIIIC(b) SEQ ID NO:1
  • cry ⁇ IIC(b) gene is also clearly distinct from the cry ⁇ IIB gene.
  • cry ⁇ IIC(b) gene SEQ ID NO:1
  • the deduced amino acid sequence of the CryIIIC (b) protein SEQ ID NO : 2
  • the protein coding portion of the cry I ⁇ IC (b) gene is defined by the nucleotides starting at position 144 and ending at position 2099.
  • the probable ribosome binding site is indicated as "RBS" in Figure 1-1.
  • CryIIIC(b) protein (SEQ ID NO: 2) encoded by the cryI ⁇ IC(b) gene, as deduced from the open reading frame of the cry ⁇ IIC(b) gene (SEQ ID NO:1), is 74,265 Da (652 amino acids). It should be noted that the apparent size of the CryIIIC(b) protein, as determined from SDS-PAGE, is approximately 70 kDa. Therefore, the CryIIIC(b) protein (SEQ ID NO:2) will be referred to in this specification as being approximately 70 kDa in size.
  • the size of the CryIIIB protein has previously been determined to be 74,237 Da (651 amino acids).
  • the nucleotide base sequence of the cry ⁇ IIC(b) gene (SEQ ID NO:1) was 96% positionally identical with the nucleotide base sequence of the cry ⁇ IIB gene and only 76% positionally identical with the nucleotide base sequence of the cryIIIA gene.
  • the cry ⁇ IIC(b) gene (SEQ ID NO:1) is related to the cryIIIB and cryIIIA genes, it is clear that the cryI ⁇ IC (b) gene is distinct from the cryIIIB gene and substantially different from the cryIIIA gene.
  • the deduced amino acid sequence of the CryIIIC(b) protein (SEQ ID NO: 2) was found to be 95% positionally identical to the deduced amino acid sequence of the
  • CryIIIB protein but only 68% positionally identical to the deduced amino acid sequence of the CryIIIA protein. These differences, together with the differences in insecticidal activity as set forth below, clearly show that the CryIIIC(b) protein encoded by the cry ⁇ IIC(b) gene (SEQ ID NO:1) is a different protein from the CryIIIB protein or the CryIIIA protein.
  • amino acids indicate the position of the amino acid in the sequence illustrated in Figure 1 and identified in SEQ ID NO: 2: His9, His231, Gln339, Ser352, Asn446, His449, Val450, Gly451, Ile600 and Thr624. These amino acid residues were selected as being of probable significance for the corn rootworm toxicity of the
  • CryIIIC(b) protein (SEQ ID NO:2) because, after studying the amino acid sequences of several other CryIII proteins, the amino acids at the indicated positions fairly
  • cry ⁇ IIC(b) gene SEQ ID NO:l
  • site directed mutagenesis of the cry ⁇ IIC(b) gene may result in improved or enhanced corn rootworm toxicity for the resultant protein where one or more of the following amino acid modifications are effected:
  • cry ⁇ IIC(b) gene SEQ ID NO:1
  • SEQ ID NO:1 changes in the cry ⁇ IIC(b) gene (SEQ ID NO:1) may be made, via site directed mutagenesis or gene truncation or the like, that could yield a toxic protein which possesses essentially similar insecticidal activity (to corn rootworm and other coleopteran insects) as that exhibited by the CryIIIC(b) protein (SEQ ID NO: 2).
  • Modifications to the cryI ⁇ IC (b) gene (SEQ ID NO:1) and CryIIIC(b) protein (SEQ ID NO:2) such as described above are intended to be within the scope of the claimed invention.
  • Table 2 summarizes the relevant characteristics of the B. t. and E. coli strains and plasmids used during these procedures.
  • a plus ( + ) indicates the presence of the designated element, activity or function and a minus (-) indicates the absence of the same.
  • the designations s and r indicate sensitivity and resistance, respectively, to the antibiotic with which each is used.
  • Amp ampicillin
  • Cm chloramphenicol
  • Cry crystalliferous
  • Tc tetracycline
  • E. coli cells harboring plasmid pEG271 described in Example 6 were analyzed and found not to produce
  • the Bacillus vector pNN101 (Tc r Cm r Cry-) that is capable of replicating in B. t. was ligated into the SphI site of pEG271.
  • the resultant plasmid was designated pEG272.
  • the isolated plasmid pEG271 DNA was digested with SphI and was then mixed with the Bacillus vector pNN101 that had also been digested with Sphl . T4 DNA ligase and ATP were added to the mixture to allow pEG271 to ligate into the SphI site of the pNN101 vector.
  • the DNA mixture was added to a suspension of E. coli strain DH5 ⁇ cells that had been treated with calcium chloride to permit the cells to take up plasmid DNA. After exposure to the recombinant
  • the E. coli host cells were spread on an agar medium containing tetracycline. Only cells that had taken up a plasmid consisting of pEG271 ligated into the SphI site of pNN101 would grow on the tetracycline agar medium whereas cells that had not absorbed the plasmid would not grow.
  • Plasmid was isolated from one tetracycline resistant colony, digested with SphI, and electrophoresed through an agarose gel.
  • the plasmid consisted of two SphI DNA fragments of 5.8 kb and 9 kb corresponding to plasmids pNN101 and pEG271, respectively. This plasmid was
  • E. coli strain GM2163 is a crystal negative (Cry-) and ampicillin sensitive (Amp s ) strain, constructed by the procedures of M.G. Marinus et al. in Mol. Gen. Genet., 192 , pp.28 ⁇ -2 ⁇ 9 (1983).
  • Plasmid pEG272 was then isolated from the transformed E. coli strain GM2163, using the procedures described above. The isolated plasmid pEG272 was next transformed by electroporation into B. t. strain HD73-26. Cells of B. t. strain HD73-26 are crystal-negative (Cry-) and chloramphenicol sensitive (Cm s ). Using a BioRad Gene
  • Pulser TM apparatus to carry out the electroporation, cells of B. t. strain HD73-26 in suspension were induced to take up pEG272 which was also added to the mixture.
  • the transformed B. t. cells were spread onto an agar medium containing 5 ⁇ g
  • sporulated culture of B. t. strain EG7237 contained spores and small free floating irregularly shaped crystals.
  • the crystals in the centrifuge pellet suspension were solubilized by heating a portion of the centrifuge
  • solubilization buffer (0.14 M Tris pH 6.8, 2% (w/v) SDS, 5% (v/v) 2-mercaptoethanol, 10% (v/v) glycerol and 0.1% (w/v) bromophenol blue) at 100°C for 5 minutes. After crystal solubilization had occurred, the mixture was applied to an SDS-polyacryamide gel and the solubilized proteins in the mixture were size fractionated by electrophoresis. After size fractionization, the proteins were visualized by staining with Coomassie dye.
  • Lane 3 of the gel in Figure 7 shows that B. t. strain EG7237 produced a major protein of approximately 70 kDa and a minor protein of approximately 30 kDa. These proteins appeared to be identical in size with the major approximately 70 kDa protein and the minor approximately 30 kDa protein produced by B. t. strain EG5144, which are shown in the lane 1 of Figure 7 and which were prepared in a manner identical to B. t. strain EG7237. This result indicates that the 7.0 kb fragment of pEG272 contains two crystal protein genes: one for the approximately 70 kDa protein and one for the approximately 30 kDa protein.
  • cryIIIC (b) gene The gene encoding the approximately 70 kDa protein is the cryIIIC (b) gene, and its encoded protein is the insecticidal CryIIIC(b) protein.
  • the DNA sequence for the cry ⁇ IIC(b) gene SEQ ID NO:1
  • the amino acid sequence for its corresponding deduced protein SEQ ID NO:2
  • B.t. strain EG7237 produced approximately three times more 70 kDa protein, on a weight basis, than did B. t.
  • strain EG5144 as is evident from the protein bands in Figure 7. Production of the minor 30 kDa protein in recombinant B. t. strain EG7237 was also increased, as compared with B. t. strain EG5144.
  • the following Examples 8-11 describe the manner in which the insecticidal activities of B. t. strain EG5144, B. t. strain EG7237, and the CryIIIC(b) protein made by these strains were determined.
  • the insecticidal activity of recombinant B. t. strain EG7237 which contains the cry ⁇ IIC (b) gene (SEQ ID NO:1) that produces the CryIIIC(b) toxin protein (SEQ ID NO: 2), was determined against southern corn rootworm (Diabrotica undecimpunctata howardi) and Colorado potato beetle
  • B. t. strain EG7235 which contains the cryIIIA gene that produces the CryIIIA toxin protein
  • recombinant B. t. strain EG7225 which contains the cryIIIB gene that produces the CryIIIB toxin protein.
  • the fermentation broth was concentrated by microfiltration.
  • the concentrated fermentation broth was then freeze dried to prepare a B. t. powder suitable for insect bioassay.
  • the amount of CryIII-type toxin protein in each of the B. t. powders was quantified using standard SDS-PAGE techniques.
  • Results are shown as the dose amount of CryIII-type protein (in ng CryIII protein per mm 2 of diet
  • B. t. strains exhibit insecticidal activity against Colorado potato beetle larvae, with the CryIIIA toxin protein of B. t. strain EG7235 being
  • Example 8 The insecticidal activity of recombinant B. t. strain EG7237, evaluated in Example 8, was also determined against Mexican bean beetle (Epilachna varivestis) . As in Example 8, recombinant B. t. strains EG7235 and EG7225 were included for comparison, and all B. t. powders were prepared as in Example 8.
  • Soybean leaves were dipped into known treatment concentrations of the B. t. powder suspended in an aqueous 0.1% Triton ® X-100 solution. After excess material had dripped off, the leaves were allowed to dry. Leaves dipped in 0.1% Triton ® X-100 served as untreated controls. Twenty insect larvae were confined to a petri dish with treated leaves,
  • insecticidal activity of specific CryIII-type toxin proteins varies widely for insect genera within the order Coleoptera.
  • B. t. strain EG5144 The insecticidal activity of B. t. strain EG5144 was evaluated against Southern corn rootworm (Diabrotica undecimpunctata howardi ). For comparison, B. t. strain EG4961 which produces the CryIIIC(a) toxin protein was included in the bioassay study.
  • the bioassay procedure for southern corn rootworm in this Example determined PLC 50 values, the concentration of CryIII-type protein required to kill 50% of the insects tested.
  • the procedure was similar to the artificial diet bioassay carried out in the previous Example, using thirty-two first instar southern corn rootworm larvae per dose. Data from each of the replicated bioassays were pooled for probit analysis (R.J. Daum,
  • Results are reported for two separate tests as the dose amount of CryIII-type protein (ng CryIII protein per mm 2 of diet surface) resulting in PLC50. Confidence intervals, at 95%, are given within parentheses following the PLC 50 values. In Test 1 four replications per dose were used, and in Test 2, carried out at a later date, two replications were used.
  • the B. t. strains used in this Example were prepared as described for the B. t. strains in Example 8, except that the fermentation broth was concentrated by
  • Test 2 6.4 1145 (773-2185)
  • B. t. EG4961 Cry ⁇ IIC(a)
  • Test 1 11.6 102 (66-119)
  • B. t. strain EG5144 The insecticidal activity of B. t. strain EG5144 was evaluated against Japanese beetle larvae, also known as white grubs (Popillia japonica) .
  • B. t. strain EG4961 which produces the CryIIIC(a) toxin protein was included in the bioassay study, as were B. t. strain EG215 ⁇ which produces the CryIIIA toxin protein and B. t. strain EG2 ⁇ 3 ⁇ which produces the CryIIIB toxin protein.
  • the bioassay procedure in this Example was a
  • Results were obtained at a single dose rate of CryIII-type protein: 1 mg CryIII-type protein per ml of diet;
  • B. t. strain EG2158 and B. t. strain EG2838 B. t. strain EG5144 exhibited superior insecticidal performance against Japanese beetle grubs.
  • B. t. strain EG5145 whose characteristics are similar to those of B.t. strain EG5144, has been found to exhibit insecticidal activity against Japanese beetle grubs equivalent to that of B. t. strain EG5144, although the bioassay data are not presented in this Example 11.
  • MOLECULE TYPE DNA (genomic)

Abstract

A Bacillus thuringiensis strain isolate, designated EG5144, exhibits insecticidal activity against coleopteran insects, including Colorado potato beetle and insects of the genus Diabrotica. A novel toxin gene in B.t. strain EG5144 produces an irregularly shaped insecticidal crystal protein of approximately 70 kDa that is toxic to coleopteran insects. The cryIII-type gene (SEQ ID NO:1), designated as the cryIIIC(b) gene, has a nucleotide base sequence illustrated in Figure 1.

Description

BACILLUS THURINGIENSIS cry IIIC(b) TOXIN
GENE AND PROTEIN TOXIC TO COLEOPTERAN INSECTS
Field of the Invention
The present invention relates to an isolated Bacillus thuringiensis strain, to its novel toxin encoding gene and to the insecticidal crystal protein toxin made by the gene, as well as to insecticidal compositions containing the protein that are toxic to coleopteran insects. Background of the Invention
Bacillus thuringiensis (hereinafter "B.t.") is a gram-positive soil bacterium that produces crystal
proteins during sporulation which are specifically toxic to certain orders and species of insects. Many different strains of B. t. have been shown to produce insecticidal crystal proteins. Compositions including B. t. strains which produce insecticidal proteins have been commercially available and used as environmentally acceptable
insecticides because they are quite toxic to the specific target insect, but are harmless to plants and other non- targeted organisms. A number of genes encoding crystal proteins have been cloned from several strains of B. t. A review of such genes is set forth in H. Höfte et al., Microbiol . Rev. , 53 , pp.242-255 (1989). This reference provides a good overview of the genes and proteins obtained from B. t. and their uses, adopts a nomenclature and classification scheme for B. t. genes and proteins, and has an extensive bibliography.
The B. t. crystal protein is toxic in the insect only after ingestion. After ingestion, the alkaline pH and proteolytic enzymes in the insect mid-gut solubilize the crystal allowing the release of the toxic components.
These toxic components disrupt the mid-gut cells causing the insect to cease feeding and, eventually, to die. In fact, B. t. has proven to be an effective and
environmentally safe insecticide in dealing with various insect pests.
As noted by Höfte et al., the majority of
insecticidal B. t. strains are active against insects of the order Lepidoptera, i.e., caterpillar insects. Other B. t. strains are insecticidally active against insects of the order Diptera, i.e., flies and mosquitoes, or against both lepidopteran and dipteran insects. In recent years, a few B. t. strains have been reported as producing crystal protein that is toxic to insects of the order Coleoptera, i.e., beetles. The first isolation of a coleopteran-toxic B. t.
strain is reported by A. Krieg et al., in Z. angew.Ent., 96, pp.500-508 (1983); see also A. Krieg et al.,
Anz.Schaedlingskde. , Pflanzenschutz, Umweltschutz, 57, pp.145-150 (1984) and U.S. Patent 4,766,203, issued August 23, 1988 of A. Krieg et al. The strain, designated B. t. var. tenebrionis, is reported to be toxic to larvae of the coleopteran insects Agelastica alni (blue alder leaf beetle) and Leptinotarsa decemlineata (Colorado potato beetle). B. t. tenebrionis makes an insecticidal crystal protein reported to be about 65-70 kilodaltons (kDa) (U.S. Patent 4,766,203; see also K. Bernhard, FEMS
Microbiol . Lett., 33 , pp.261-265 (1986)).
V. Sekar et al., Proc. Natl . Acad. Sci . USA, 84 , pp.7036-7040 (1987), report the cloning and characterization of the gene for the coleopteran-toxic crystal protein of B. t. tenebrionis . The size of the protein, as deduced from the sequence of the gene, was 73 kDa, but the isolated protein contained primarily a 65 kDa component. Hόfte et al., Nucleic Acids Res. , 15, p.7183 (1987), also report the DNA sequence for the cloned gene from B. t. tenebrionis , and the sequence of the gene is identical to that reported by Sekar et al. (1987).
McPherson et al., Bio/Technology, 6 , pp.61-66 (1988), disclose the DNA sequence for the cloned insect control gene from B. t. tenebrionis , and the sequence is identical to that reported by Sekar et al. (1987). E. coli cells and Pseudomonas fluorescenε cells harboring the cloned gene were found to be toxic to Colorado potato beetle larvae.
PCT International Publication No. WO 91/07481 dated May 30, 1991, of Novo Nordisk A/S, describes B. t. mutants that produce high yields of the same insecticidal proteins originally made by the parent strains at lesser yields. Mutants of the coleopteran-toxic B. t. tenebrionis strain are disclosed.
A coleopteran-toxic strain, designated B. t. var. san diego, is reported by C. Herrnstadt et al.,
Bio/Technology, 4 , pp.305-308 (1986), to produce a 64 kDa crystal protein that was toxic to various coleopteran insects: strong toxicity to Pyrrhalta luteola (elm leaf beetle); moderate toxicity to Anthonomus grandis (boll weevil), Leptinotarsa decemlineata (Colorado potato beetle), Otiorhynchus sulcatus (black vine weevil),
Tenebrio molitor (yellow mealworm) and Haltica tombacina; and weak toxicity to Diabrotica undecimpunctata
undecimpunctata (western spotted cucumber beetle).
The DNA sequence of the cloned coleopteran toxin gene of B. t. san diego is reported in C. Herrnstadt et al., Gene, 57, pp.37-46 (1987); see also U.S. Patent 4,771,131, issued September 13, 1988, of Herrnstadt et al. The sequence of the toxin gene of B. t. san diego is identical to that reported by Sekar et al. (1987) for the cloned coleopteran toxin gene of B. t. tenebrionis . A. Krieg et al., J.Appl .Ent. , 104 , pp.417-424 (1987), report that the strain B. t. san diego is identical to the B. t. tenebrionis strain, based on various diagnostic tests.
Another new B. t. strain, designated EG2158, is reported by W.P. Donovan et al., in Mo 1. Gen. Gene t. , 214 , pp.365-372 (1988) and in U.S. Patent No. 5,024,837 issued June 18, 1991, to produce a 73 kDa crystal protein that is insecticidal to coleopteran insects. The toxin-encoding gene from B. t. strain EG2158 was cloned and sequenced, and its sequence is identical to that reported by Sekar et al. (1987) for the cloned B. t. tenebrionis coleopteran toxin gene. This coleopteran toxin gene is referred to as the cryΙIIA gene by Hόfte et al., Microbiol . Rev. , 53 , pp.242-255 (1989).
The Donovan et al. '837 U.S. patent noted above also describes hybrid B. t. var. kurstaki strains designated EG2424 and EG2421, which are active against both
lepidopteran insects and coleopteran insects. The beetle activity of these hybrid strains results from the
coleopteran toxin plasmid transferred from B. t. strain EG2158 by conjugal plasmid transfer.
U.S. Patent 4,797,279, issued January 10, 1989, of D. Karamata et al. (corresponding to EP-A-0 221 024),
discloses a hybrid B. t. microorganism containing a plasmid from B. t. var. kurstaki with a lepidopteran toxin gene and a plasmid from B. t . tenebrionis with a coleopteran toxin gene. The hybrid B. t. produces crystal proteins
characteristic of those made by B. t. kurstaki , as well as those of B. t. tenebrionis.
U.S. Patent No. 4,910,016, issued March 20, 1990, of Gaertner et al. (corresponding to EP-A-0 303 379), discloses a novel B. t. isolate identified as B. t. MT 104 which has insecticidal activity against two orders of insects, Colorado potato beetle (Coleoptera) and cabbage looper (Lepidoptera).
European Patent Application Publication No. 0 318 143, published May 31, 1989, of Lubrizol Genetics, Inc., discloses the cloning, characterization and selective expression of the intact partially modified gene from B. t. tenebrionis, and the transfer of the cloned gene into a host microorganism rendering the microorganism able to produce a protein having toxicity to coleopteran insects. Insect bioassay data for B. t. san diego reproduced from Herrnstadt et al., Bio/Technology, 4 , pp.305-308 (1986) discussed above, is summarized. The summary also includes data for B. t. tenebrionis from another source; B. t.
tenebrionis is reported to exhibit strong toxicity to Colorado potato beetle, moderate toxicity to western corn rootworm (Diabrotica virgifera) and weak toxicity to southern corn rootworm (Diabrotica undecimpunctata).
European Patent Application Publication No. 0 324 254, published July 19, 1989, of Imperial Chemical
Industries PLC, discloses a novel B. t. strain identified as A30 which has insecticidal activity against coleopteran insects, including Colorado potato beetle larvae, corn rootworm larvae and boll weevils.
U.S. Patent No. 4,999,192, issued March 12, 1991, of Payne et al. (corresponding to EP A-0 328 383), discloses a novel B. t. microorganism identified as B. t. PS40D1 which has insecticidal activity against Colorado potato beetle larvae. B. t. strain PS40D1 is identified via serotyping as being serovar 8a8b, morrisoni .
U.S. Patent No. 5,006,336, issued April 9, 1991, of Payne et al. (corresponding to EP-A-0 346 114), discloses a novel B. t. isolate designated as PS122D3, which is serotyped as serovar 8a8b, morrisoni and which exhibits insecticidal activity against Colorado potato beetle larvae.
U.S. Patent No. 4,966,765, issued October 30, 1990, of Payne et al. (corresponding to EP-A-0 330 342),
discloses a novel B. t. microorganism identified as B. t. PS86B1 which has insecticidal activity against the
Colorado potato beetle. B. t. strain PS86B1 is identified via serotyping as being serovar tolworthi .
The nucleotide sequence of a cry IIIB gene and its encoded coleopteran-toxic protein is reported by Sick et al., in Nucleic Acids Res. , 18 , p.1305 (1990) but the B. t. source strain is identified only via serotyping as being subspecies tolworthi . U.S. Patent No. 4,966,155, issued February 26, 1991, of Sick et al. (corresponding to EP-A-0 337 604), discloses a B. t. toxin gene obtained from the coleopteran-active B. t. strain 43F, and the gene sequence appears identical to the cryIIIB gene. B. t. strain 43F is reported as being active against Colorado potato beetle and Leptinotarsa texana.
European Patent Application No. 0 382 990, published August 22, 1990, of Plant Genetic Systems N.V., discloses two novel B. t. strains (btGSI208 and btGSI245) producing respective crystal proteins of 74 and 129 kDa that exhibit insecticidal activity against Colorado potato beetle larvae. The DNA sequence reported for toxin gene
producing the 74 kDa protein appears to be identical to that of the cryIIIB gene of Sick et al.
PCT International Publication No. WO 90/13651, published November 15, 1990, of Imperial Chemical
Industries PLC, discloses novel B. t. strains which contain a toxin gene encoding an 81 kDa protein that is stated to be toxic not only to lepidopteran insects but also to coleopteran insects, including Diabrotica.
U.S. Patent No. 5,055,293, issued October 8, 1991, of Aronson et al., discloses the use of B. laterosporouε for corn rootworm (Diabrotica) insect control.
The various B. t. strains described in aforementioned literature are reported to have crystal proteins
insecticidally active against coleopteran insects, but none has been demonstrated to have significant,
quantifiable toxicity to the larvae and adults of the insect genus Diabrotica (corn rootworm), which includes the western corn rootworm (Diabrotica virgifera
virgifera), the southern corn rootworm (Diabrotica undecimpunctata howardi) and the northern corn rootworm (Diabrotica barberi) .
The B. t. strain of the present invention contains a novel toxin gene that expresses protein toxin having quantifiable insecticidal activity against the Diabrotica insects, among other coleopteran insects.
Summary of the Invention
One aspect of the present invention relates to a purified and isolated coleopteran toxin gene having a nucleotide base sequence coding for the amino acid
sequence illustrated in Figure 1 and hereinafter
designated as the cryΙIIC (b) gene (SEQ ID NO:1). The cryΙIIC(b) gene (SEQ ID NO:1) has a coding region
extending from nucleotide bases 144 to 2099 shown in
Figure 1.
Another aspect of the present invention relates to the insecticidal protein produced by the cryΙIIC (b) gene . The CryΙIIC(b) protein (SEQ ID NO: 2) has the amino acid sequence, as deduced from the nucleotide sequence of the cryΙIIC(b) gene (SEQ ID NO:1) from nucleotide bases 144 to 2099 that is shown in Figure 1. The protein exhibits insecticidal activity against insects of the order Coleoptera, in particular, Colorado potato beetle and insects of the genus Diabrotica .
Still another aspect of the present invention relates to a biologically pure culture of a B. t. bacterium
deposited with the Agricultural Research Culture
Collection, Northern Regional Research Laboratory (NRRL) having Accession No. NRRL B-18655 and being designated as B. t. strain EG5144 and a biologically pure culture of a second bacterium deposited with the NRRL having Accession No. NRRL B-18920 and being designated as B. t. strain
EG5145. B. t. strain EG5144 is a wild-type B. t. strain that carries the cryΙIIC(b) gene (SEQ ID NO:1) and produces the insecticidal CryΙIIC(b) protein (SEQ ID
NO:2). B. t. strain EG5145 is also a wild-type B. t.
strain, whose characteristics are similar to those of B. t. strain EG5144 described in more detail below.
Biologically pure cultures of other B. t. bacteria carrying the cryΙIIC(b) gene (SEQ ID NO:1) are also within the scope of this invention.
Yet another aspect of this invention relates to insecticidal compositions containing, in combination with an agriculturally acceptable carrier, either the
CryΙIIC(b) protein (SEQ ID NO: 2) or fermentation cultures of a B. t . strain which has produced the CryΙIIC(b)
protein.
The invention also includes a method of controlling coleopteran insects by applying to a host plant for such insects an insecticidally effective amount of the
CryΙIIC(b) protein (SEQ ID NO: 2) or of a fermentation culture of a B. t. strain that has made the CryΙIIC(b) protein. The method is applicable to a variety of coleopteran insects, such as the Colorado potato beetle, Japanese beetle larvae (white grubs), Mexican bean beetle and corn rootworm.
Still another aspect of the present invention relates to a recombinant plasmid containing the cryΙIIC(b) gene (SEQ ID NO:l), a biologically pure culture of a bacterium transformed with such recombinant plasmid, the bacterium preferably being B. t. , such as B. t. strain EG7237
described in Example 6, as well as a plant transformed with the cryΙIIC(b) gene.
Brief Description of the Drawings
Figure 1 comprises Figures 1-1 through 1-3 and shows the nucleotide base sequence of the cryΙIIC (b) gene (SEQ ID NO:1) and the deduced amino acid sequence of the
CryΙIIC(b) protein (SEQ ID NO: 2). The putative ribosome binding site (RBS) is indicated. Restriction sites for Sspl and ffindIII are also indicated.
Figure 2 is a photograph of an ethidium bromide stained agarose gel containing size fractionated native plasmids of B. t. strains EG5144 (lane 1), EG4961 (lane 2), EG2838 (lane 3) and EG2158 (lane 4). The numbers to the left of Figure 2 indicate the approximate sizes, in megadaltons (MDa), of the plasmids of B. t. strain EG5144.
Figure 3 is a photograph of an autoradiogram made by transferring size fractionated DNA fragments from an agarose gel to a nitrocellulose filter, hybridizing the filter with a radioactively labeled 2.4 kilobases (kb) cryIIIB probe, and exposing the filter to X-ray film. The agarose gel contained size fractionated total DNA
fragments from B. t. strains EG2158, EG5144, EG2838 and EG4961, that had been obtained in separate digestions with the restriction enzymes SspI, HindIII and EcoRI. The numbers to the left of Figure 3 indicate the sizes, in kb, of B. t. strain EG5144 restriction fragments that
hybridized to the cryΙIIB probe. The lane labeled "stnd" is a size standard.
Figure 4 is a photograph of a Coomassie stained sodium dodecyl sulfate ("SDS") polyacrylamide gel showing crystal proteins solubilized from B. t. strains EG5144 (lane 1), EG4961 (lane 2) , EG2158 (lane 3) and EG2838 (lane 4). The numbers to the left of Figure 4 indicate the approximate sizes in kDa of the crystal proteins produced by B. t. strain EG5144. Lane 5 contains protein molecular size standards.
Figure 5 shows a restriction map of plasmid pEG271. The location and orientation of the cryΙIIC(b) gene (SEQ ID NO:1) is indicated by the arrow. Plasmid pEG271 is functional in Escherichia coli (E. coli) , since it contains E. coli plasmid pUC18 (Apr), indicated by the segment marked pUC18. The abbreviations for the restriction endonuclease cleavage sites are as follows: Ba=BamHI; Bg=BglII; H=HindIII; R=EcoRI , S=SphI ; and X=XbaI. A one kilobase scale marker is also illustrated.
Figure 6, aligned with and based on the same scale as Figure 5, shows a restriction map of plasmid pEG272. The location and orientation of the cryΙIIC(b) gene (SEQ ID NO:1) is indicated by the arrow shown in Figure 5.
Plasmid pEG272 is derived from plasmid pEG271 (Figure 5) and contains the Bacillus plasmid pNN101 (Cmr Tcr), indicated by the segment marked pNN101 and is incorporated into the SphI site of pEG271; this plasmid is functional in B. t. Abbreviations are the same as those for Figure 5.
Figure 7 is a photograph of a Coomassie stained SDS-polyacrylamide gel. The gel shows protein bands
synthesized by B. t. strain EG5144 (lane 1) and by
recombinant B. t. strain EG7237 containing pEG272 (lane 3). Lane 2 contains a protein size standard and the numbers on either side of lanes 1 and 3 indicate approximate sizes, in kDa, of the crystal proteins produced by these strains.
Detailed Description of the Preferred Embodiments
The isolation and purification of the cryΙIIC (b) gene (SEQ ID NO:1) and the coleopteran-toxic CryΙIIC(b) crystal protein (SEQ ID NO: 2) and the characterization of the new B. t. strain EG5144 which produces the CryΙIIC(b) protein are described at length in Examples 1-7. The utility of B. t. strain EG5144 and of the CryΙIIC(b) crystal protein (SEQ ID NO:2) in insecticidal compositions and methods is also illustrated in Examples 8-11.
The cryIII-type gene of this invention, the
cryΙIIC(b) gene (SEQ ID NO:1), has the nucleotide base sequence shown in Figure 1. The coding region of the cryΙIIC(b) gene (SEQ ID NO:1) extends from nucleotide base position 144 to position 2099 shown in Figure 1.
A comparison of the nucleotide base sequence of the cryΙIIC(b) gene coding region with the corresponding coding region of the prior art cryIIIA gene indicates significant differences between the two genes. The cryΙIIC(b) gene (SEQ ID NO:1) is only 76% homologous
(positionally identical) with the cryIIIA gene.
A comparison of the nucleotide base sequence of the cryΙIIC(b) gene coding region with the corresponding coding region of the cryIIIB gene obtained from recently discovered B. t. strain EG2838 (NRRL Accession No. B-18603) indicates that the cryIIIC(b) gene (SEQ ID NO:1) is 96% homologous (positionally identical) with the cryIIIB gene.
The CryIII-type protein of this invention, the
CryΙIIC(b) protein, that is encoded by the cryΙIIC(b) gene (SEQ ID NO:1), has the amino acid sequence (SEQ ID NO:2) shown in Figure 1. In this disclosure, references to the CryΙIIC(b) "protein" are synonymous with its description as a "crystal protein", "protein toxin", "insecticidal protein" or the like, unless the context indicates otherwise. The size of the CryΙIIC(b) protein (SEQ ID NO:2), as deduced from the DNA sequence of the cryΙIIC(b) gene (SEQ ID NO:1), is 74,265 Daltons (Da).
The size of the CryIIIB protein, as deduced from the sequence of the cryIIIB gene, is 74,237 Da. The prior art CryIIIA protein, encoded by the cryIIIA gene, has a deduced size of 73,116 Da.
Despite the apparent size similarity, comparison of the amino acid sequence of the CryΙIIC(b) protein (SEQ ID NO: 2) with that of the prior art CryIIIA protein shows significant differences between the two. The CryΙIIC(b) protein (SEQ ID NO:2) is only 68% homologous (positionally identical amino acids) with the CryIIIA protein. The CryΙIIC(b) protein (SEQ ID NO:2) is 95% homolgous with the CryIIIB protein. Nevertheless, despite the apparent homology of the CryΙIIC(b) and CryIIIB proteins, the
CryΙIIC(b) protein (SEQ ID NO: 2) has been shown to be a different protein than the CryIIIB protein, based on its significantly improved insecticidal activity compared to the CryIIIB protein with respect to insects of the order Coleoptera and in particular, insects of the genus
Diabrotica . The CryΙIIC(b) protein (SEQ ID NO:2), unlike the CryIIIB protein, exhibits quantifiable insecticidal activity against corn rootworm larvae.
The present invention is intended to cover mutants and recombinant or genetically engineered derivatives, e.g., truncated versions, of the cryΙIIC(b) gene (SEQ ID NO:1) that yield a protein with insecticidal properties essentially the same as those of the CryΙIIC(b) protein (SEQ ID NO:2).
The cryΙIIC(b) gene (SEQ ID NO:1) is also useful as a DNA hybridization probe, for discovering similar or closely related cryIII-type genes in other B. t. strains. The cryΙIIC(b) gene (SEQ ID NO:1), or portions or
derivatives thereof, can be labeled for use as a
hybridization probe, e.g., with a radioactive label, using conventional procedures. The labeled DNA hybridization probe may then be used in the manner described in the Examples.
The cryΙIIC(b) gene (SEQ ID NO:1) and the
corresponding insecticidal CryΙIIC(b) protein (SEQ ID
NO:2) were first identified in B. t. strain EG5144, a novel B. t. isolate. The characteristics of B.t. strain EG5144 are more fully described in the Examples. Comparison of the plasmid arrays and other strain characteristics of B. t. strain EG5144 with those of the recently discovered B. t. strains EG2838 and EG4961 and those of the prior art B. t. strain EG2158 and B. t. var. tenebrionis (or the equivalent, B. t. var. san diego) demonstrates that each of these coleopteran-toxic B. t. strains is distinctly
different. The plasmid array of B. t. strain EG5145, another wild-type strain isolated along with B. t. strain EG5144, is similar to that of B. t. strain EG5144, and B. t. strain EG5145 exhibits the same insecticidal activity against coleopteran insects, e.g., Japanese beetle larvae, as that of B. t . strain EG5144 (see Example 11).
The cry IΙIC(b) gene (SEQ ID NO:1) may be introduced into a variety of microorganism hosts, using procedures well known to those skilled in the art for transforming suitable hosts under conditions which allow for stable maintenance and expression of the cloned cryΙIIC(b) gene. Suitable hosts that allow the cryΙIIC (b) gene (SEQ ID NO:1) to be expressed and the CryΙIIC(b) protein (SEQ ID NO: 2) to be produced include Bacillus thuringiensis and other Bacillus species such as B. subtilis or B.
megaterium. It should be evident that genetically altered or engineered microorganisms containing the cryΙIIC (b) gene (SEQ ID NO:1) can also contain other toxin genes present in the same microorganism and that these genes could concurrently produce insecticidal crystal proteins different from the CryIIIC(b) protein.
The Bacillus strains described in this disclosure may be cultured using conventional growth media and standard fermentation techniques. The B. t. strains harboring the cryΙIIC(b) gene (SEQ ID NO:1) may be fermented, as
described in the Examples, until the cultured B. t. cells reach the stage of their growth cycle when CryIIIC(b) crystal protein (SEQ ID NO: 2) is formed. For sporogenous B. t. strains, fermentation is typically continued through the sporulation stage when the CryIIIC (b) crystal protein is formed along with spores. The B. t. fermentation culture is then typically harvested by centrifugation, filtration or the like to separate fermentation culture solids, containing the CryIIIC(b) crystal protein, from the aqueous broth portion of the culture.
The B. t. strains exemplified in this disclosure are sporulating varieties (spore forming or sporogenous strains) but the cryΙIIC(b) gene (SEQ ID NO:1) also has utility in asporogenous Bacillus strains, i.e., strains that produced the crystal protein without production of spores. It should be understood that references to
"fermentation cultures" of B. t. strains (containing the cryIIIC(b) gene (SEQ ID NO:1)) in this disclosure are intended to cover sporulated B. t. cultures, i.e., B. t. cultures containing the CryIIIC(b) crystal protein and spores, and sporogenous Bacillus strains that have produced crystal protein during the vegetative stage, as well as asporogenous Bacillus strains containing the cryIIIC(b) gene (SEQ ID NO:1) in which the culture has reached the growth stage where crystal protein is actually produced.
The separated fermentation solids are primarily
CryIIIC(b) crystal protein (SEQ ID NO:2) and B. t. spores, along with some cell debris, some intact cells, and residual fermentation medium solids. If desired, the crystal protein may be separated from the other recovered solids via conventional methods, e.g., sucrose density gradient fractionation. Highly purified CryIIIC(b) protein (SEQ ID NO: 2) may be obtained by solubilizing the recovered crystal protein and then precipitating the protein from solution.
The CryIIIC(b) protein (SEQ ID NO: 2), as noted earlier, is a potent insecticidal compound against
coleopteran insects, such as the Colorado potato beetle, Japanese beetle larvae (white grubs), Mexican bean beetle and the like. The CryIIIC(b) protein (SEQ ID NO: 2), in contrast to the CryIIIA and CryIIIB proteins, exhibits measurable insecticidal activity against Diabrotica insects, e.g., corn rootworms, which have been relatively unaffected by other coleopteran-toxic B. t. crystal
proteins. The CryIIIC(b) protein (SEQ ID NO: 2) may be utilized as the active ingredient in insecticidal
formulations useful for the control of coleopteran insects such as those mentioned above. Such insecticidal
formulations or compositions typically contain
agriculturally acceptable carriers or adjuvants in
addition to the active ingredient and are prepared and used in a manner well known to those skilled in the art.
The CryIIIC(b) protein (SEQ ID NO: 2) may be employed in insecticidal formulations in isolated or purified form, e.g., as the crystal protein itself. Alternatively, the CryIIIC(b) protein (SEQ ID NO: 2) may be present in the recovered fermentation solids, obtained from culturing of a Bacillus strain, e.g., Bacillus thuringiensis , or other microorganism host carrying the cryΙIIC(b) gene (SEQ ID NO:1) and capable of producing the CryIIIC(b) protein. Preferred Bacillus hosts include B. t. strain EG5144 and genetically improved B. t. strains derived from B. t. strain EG5144. The latter B. t. strains may be obtained via plasmid curing and/or conjugation techniques and contain the native cryIIIC(b) gene-containing plasmid from B. t. strain EG5144. Genetically engineered or transformed B. t. strains or other host microorganisms containing a
recombinant plasmid that expresses the cloned cryIIIC (b) gene (SEQ ID NO:1), obtained by recombinant DNA
procedures, may also be used.
An example of such transformants is B. t. strain
EG7237, which contains the cloned cryΙIIC(b) gene (SEQ ID NO:1) on a recombinant plasmid.
The recovered fermentation solids contain primarily the crystal protein and (if a sporulating B. t. host is employed) spores; cell debris and residual fermentation medium solids may also be present. The recovered
fermentation solids containing the CryIIIC(b) protein may be dried, if desired, prior to incorporation in the insecticidal formulation.
The formulations or compositions of this invention containing the insecticidal CryIIIC (b) protein (SEQ ID NO: 2) as the active component are applied at an
insecticidally effective amount which will vary depending on such factors as, for example, the specific coleopteran insects to be controlled, the specific plant or crop to be treated and the method of applying the insecticidally active compositions. An insecticidally effective amount of the insecticide formulation is employed in the insect control method of this invention.
The insecticide compositions are made by formulating the insecticidally active component with the desired agriculturally acceptable carrier. The formulated
compositions may be in the form of a dust or granular material, or a suspension in oil (vegetable or mineral) or water or oil/water emulsions, or as a wettable powder, or in combination with any other carrier material suitable for agricultural application. Suitable agricultural carriers can be solid or liquid and are well known in the art. The term "agriculturally acceptable carrier" covers all adjuvants, e.g., inert components, dispersants, surfactants, tackifiers, binders, etc. that are ordinarily used in insecticide formulation technology; these are well known to those skilled in insecticide formulation.
The formulations containing the CryIIIC(b) protein (SEQ ID NO: 2) and one or more solid or liquid adjuvants are prepared in known manners, e.g., by homogeneously mixing, blending and/or grinding the insecticidally active CryIIIC (b) protein component With suitable adjuvants using conventional formulation techniques.
The insecticidal compositions of this invention are applied to the environment of the target coleopteran insect, typically onto the foliage of the plant or crop to be protected, by conventional methods, preferably by spraying. Other application techniques, e.g., dusting, sprinkling, soaking, soil injection, seed coating,
seedling coating or spraying, or the like, are also feasible and may be required for insects that cause root or stalk infestation. These application procedures are well known in the art.
The cryIIIC(b) gene (SEQ ID NO:1) or its functional equivalent, hereinafter sometimes referred to as the
"toxin gene," can be introduced into a wide variety of microorganism hosts. Expression of the cryIIIC (b) gene (SEQ ID NO:1) results in the production of insecticidal CryIIIC(b) crystal protein toxin (SEQ ID NO:2). Suitable hosts include B. t. and other species of Bacillus, such as B. εubtilis or B. megaterium, for example. Plant- colonizing or root-colonizing microorganisms may also be employed as the host for the cryIIIC(b) gene (SEQ ID
NO:1). Various procedures well known to those skilled in the art are available for introducing the cryIIIC(b) gene (SEQ ID NO:1) into the microorganism host under conditions which allow for stable maintenance and expression of the gene in the resulting transformants.
The transformants, i.e., host microorganisms that harbor a cloned gene in a recombinant plasmid, can be isolated in accordance with conventional methods, usually employing a selection technique, which allows growth of only those host microorganisms that contain a recombinant plasmid. The transformants then can be tested for
insecticidal activity. Again, these techniques are standard procedures.
Characteristics of particular interest in selecting a host cell for purposes of production include ease of introducing the gene into the host, availability of expression systems, efficiency of expression, stability of the CryIIIC(b) insecticidal protein in the host, and the presence of auxiliary genetic capabilities. The cellular host containing the insecticidal cryΙIIC(b) gene (SEQ ID NO:1) may be grown in any convenient nutrient medium, where expression of the cryΙIIC (b) gene is obtained and CryIIIC(b) protein (SEQ ID NO:2) produced, typically to sporulation. The sporulated cells containing the crystal protein may then be harvested in accordance with
conventional methods, e.g., centrifugation or filtration.
The cryΙIIC(b) gene (SEQ ID NO:1) may also be
incorporated into a plant which is capable of expressing the gene and producing CryIIIC(b) protein (SEQ ID NO: 2), rendering the plant more resistant to insect attack.
Genetic engineering of plants with the cryΙIIC (b) gene (SEQ ID NO:1) may be accomplished by introducing the desired DNA containing the gene into plant tissues or cells, using DNA molecules of a variety of forms and origins that are well known to those skilled in plant genetic engineering. An example of a technique for introducing DNA into plant tissue is disclosed in European Patent Application Publication No. 0 289 479, published November 2, 1988, of Monsanto Company.
DNA containing the cryΙIIC(b) gene (SEQ ID NO:1) or a modified cryΙIIC(b) gene capable of producing the
CryIIIC(b) protein (SEQ ID NO: 2) may be delivered into the plant cells or tissues directly by infectious plasmids, such as Ti, the plasmid from Agrobacterium tumefaciens, viruses or microorganisms like A. tumefaciens, by the use of lysosomes or liposomes, by microinjection by mechanical methods and by other techniques familiar to those skilled in plant genetic engineering.
Variations may be made in the cryΙIIC (b) gene
nucleotide base sequence (SEQ ID NO:1), since the various amino acids forming the protein encoded by the gene usually may be determined by more than one codon, as is well known to those skilled in the art. Moreover, there may be some variations or truncation in the coding regions of the cryΙIIC(b) nucleotide base sequence which allow expression of the gene and production of functionally equivalent forms of the CryIIIC(b) insecticidal protein. These variations which can be determined without undue experimentation by those of ordinary skill, in the art with reference to the present specification are to be
considered within the scope of the appended claims, since they are fully equivalent to the specifically claimed subject matter. The present invention will now be described in more detail with reference to the following specific, non-limiting examples. The examples relate to work which was actually done based on techniques generally known in the art and using commercially available equipment.
The novel B. t. strain EG5144 was isolated following the procedure described in Example 1. The procedures described in Example 1 were also used to isolate the novel B. t. strain EG5145.
Example 1
Isolation of B. t. Strains EG5144 and EG5145 Crop dust samples were obtained from various sources throughout the U.S. and abroad, typically grain storage facilities. The crop dust samples were treated by
suspending the crop dust in an aqueous buffer and heating the suspension at 60°C for 30 min. to enrich for heat resistant spore forming Bacillus-type bacteria such as B. t. The treated dust suspensions were diluted in aqueous buffer, and the dilutions were spread on agar plates to allow each individual bacterium from the crop dust to grow into a colony on the surface of the agar plate. After growth, a portion of each colony was transferred from the agar plate to a nitrocellulose filter. The filter was treated with NaOH to lyse the colonies and to fix the DNA from each colony onto the filter. A modified treatment procedure was developed for use with B. t. colonies utilized in the colony hybridization procedure, since standard techniques applicable to E. coli were found to be unworkable with B. t. In the treatment described above, special conditions were required to assure that the B. t. colonies were in a vegetative state of growth, making them susceptible to lysis with NaOH. Accordingly, after a portion of each colony was
transferred to the nitrocellulose filter, the filter was placed colony side up on an agar medium containing 0.5% (w/v) glucose. The transferred colonies were then allowed to grow on the agar-glucose medium for 5 hours at 30°C. Use of 0.5% glucose in the agar medium and the 5-hour, 30°C growth cycle were critical for assuring that the B. t. colonies were in a vegetative state and thus susceptible to lysis.
A cloned coleopteran toxin gene was used as a
specific probe to find other novel and rare coleopteran-toxic strains of B. t. from crop dust samples. A 2.9 kb HindIII DNA restriction fragment containing the cryΙIIA gene, formerly known as the cryC gene of B. t. strain
EG2158, described in Donovan et al., Mol . Gen. Genet. , 214 , pp.365-372 (1988), was used as a probe in colony
hybridization procedures.
The 2.9 kb HindIII cryIIIA DNA fragment, containing the entire cryIIIA gene, was radioactively labeled with [alpha-P32]-dATP and Klenow enzyme, by standard methods. The nitrocellulose filters containing the DNA from each lysed colony were incubated at 65°C for 16 hours in a buffered solution that contained the radioactively labeled 2.9 kb HindIII cryΙIIA DNA probe to hybridize the DNA from the colonies with the DNA from the radioactively labeled cryΙIIA probe. The 65°C hybridization temperature was used to assure that the cryIII A DNA probe would hybridize only to DNA from colonies that contained a gene that was similar to the cryΙIIA DNA probe.
The 2.9 kb cryΙIIA probe hybridized to many B. t.
colonies from various samples of crop dust. Examination of these colonies revealed, unexpectedly, that they did not contain any cryIII-type genes. These colonies did contain cryI-type genes. The cry I-type genes encode lepidopteran-toxic, coleopteran-nontoxic crystal proteins with molecular masses of approximately 130 kDa. Computer- assisted comparisons of the sequence of the cryIIIA gene with the sequence of several cryI-type genes revealed that the 3'-end of the cryIIIA gene was partially homologous with portion of the cryI-type genes. This finding
supported the belief that the 3'-end of the cryΙIIA gene was causing the 2.9 kb cryΙIIA probe to hybridize to B. t. colonies containing cryJ-type genes.
To correct this problem, the 2.9 kb HindIII cryIII A probe was digested with the enzyme XbaI and a 2.0 kb
HindIII-XbaI fragment was purified that contained the cryIIIA gene minus its 3'-end. The 2.0 kb HindIII-XbaI fragment contains the 3'-truncated cryIIIA gene. When the 2.0 kb fragment was used in repeated colony hybridization experiments, it did not hybridize to cryI gene-containing B. t. colonies.
Approximately 48,000 Bacillus-type colonies from crop dust samples from various locations were probed with the radioactively labeled 2.0 kb HindΙII-Xbax cryΙIIA probe. Only one novel B. t. strain from an Illinois crop dust sample was discovered that specifically hybridized to the cryIIIA probe. That novel strain was designated B. t.
strain EG2838, which has been deposited with the NRRL under Accession No. NRRL B-18603.
Subsequently, approximately 50,000 additional
Bacillus-type colonies from crop dust samples were also screened with the radioactively labeled 2.0 kb HindIII-XbaI cryIIIA probe, but without success in identifying any other strains containing novel cryIII-type genes.
B. t. strain EG2838 was found to be insecticidally active against coleopteran insects, notably, the Colorado potato beetle. B. t. strain EG2838 did not have
substantial insecticidal activity with respect to the southern corn rootworm. A gene, designated the cryIIIB gene, was isolated from B. t. strain EG2838, and its nucleotide base sequence determined. The cryIIIB gene encoded a crystal protein, designated the CryIIIB protein, containing 651 amino acids having a deduced size of 74,237 Daltons. The size of the prior art CryIIIA protein had previously been deduced to be 73,116 Daltons (644 amino acids). The cryIIIB gene is 75% homologous with the cryIIIA gene, and the CryIIIB protein is 68% homologous with the CryIIIA protein.
Thousands of Bacillus-type colonies from numerous crop dust samples from various locations from around the world were screened with a cryΙIIB probe obtained from B. t. strain EG2838. The cryIIIB probe was radioactively labeled using the procedure set forth above with respect to the radioactively labeled cryIIIA probe. The
radioactively labeled cryIIIB probe consisted of a 2.4 kb Sspl restriction fragment of DNA from B. t. strain EG2838. The fragment contains the complete protein coding region for the coleopteran toxin cryIIIB gene of B. t. strain EG2838. Ultimately, the B. t. strains of the present invention, designated B. t. strains EG5144 and EG5145, were isolated from a crop dust sample via B. t. colonies that specifically hybridized to the cryIIIB probe.
To characterize B. t. strain EG5144, several studies were conducted. One series of studies was performed to characterize its flagellar serotype. Additional studies were conducted to determine the sizes of the native plasmids in B. t. strain EG5144 and to ascertain which plasmids contained genes that encoded coleopteran-active insecticidal crystal proteins. DNA blot analysis was thereafter performed using size fractionated total DNA restriction fragments from B. t. strain EG5144, compared with similarly-processed total DNA from other B. t. strains containing cry III-type toxin genes, to demonstrate that B. t. strain EG5144 contains a unique coleopteran-active toxin gene. In addition, B. t. strain EG5144 was evaluated further by characterizing the crystal proteins it produces and by measuring the insecticidal activity associated with B. t. strain EG5144 and its crystal proteins. Examples 2 through 7 are directed to the procedures for
characterizing B. t. strain EG5144 and its unique cryΙII- type gene, and Examples 8 through 11 are directed to the insecticidal activity of B. t. strain EG5144 and of B. t. strain EG7237, containing the cryΙIIC(b) gene (SEQ ID NO:l) of this invention. Example 2
Evaluation of the Flagellar Serotype of B. t. Strain EG5144
Flagellar serotyping studies were carried out with B. t. strain EG5144, using an antibody mediated cell agglutinization assay (Craigie et al., J. Immunol . , 21 , pp.417-511 (1936)). Flagellar antibody reagents were prepared using purified flagella from B. t. var. kurstaki, morrisoni and tolworthi type-strains and from the novel coleopteran-active B. t. strain EG4961.
The study included formalin-fixed vegetative cells of B. t. strain EG5144 and of cells of other coleopteran-active B. t. strains and of several common B.t. type- strains, each of which were scored for flagellar antibody mediated cell agglutinization.
The other coleopteran-active B.t. strains included B.t. var. tenebrionis, B.t. var. san diego, B.t. strain EG2158 (all containing the cryIIIA gene); B.t. strain EG2838 (containing the cryIIIB gene); and B.t. strain EG4961 (containing a novel coleopteran toxin-encoding gene designated as the cryΙIIC(a) gene).
The B.t. flagellar type-strains were B.t. var.
kurstaki (HD-1, serotype 3ab), B.t. var. morrisoni (HD-12, serotype 8ab) and B.t. var. tolworthi (HD-13, serotype 9).
Results of this study are shown in Table 1; "+" indicates that a cross-reaction occurred and "-" indicates that no cross-reaction occurred.
Table 1
Flagellar Antibody Reagent
Cells kurstaki morrisoni tolworthi EG4961
B.t. strain EG5144 - - - B.t. var. tenebrionis - + - -
B.t. var. san diego - + - -
B.t. strain EG2158 - + - -
B.t. strain EG2838 - - + -
B.t. strain EG4961 - - - + Other B. t. flagellar type-strains:
B. t. var. kurstaki (HD-1) + - - - B. t. var. morrisoni (HD-12) + - B. t. var. tolworthi (HD-13) - - + - The results in Table 1 show that cells of B. t. strain EG5144 gave a negative reaction with B. t. type-strain kurstaki , morrisoni and tolworthi flagella antibody reagents. B. t. strain EG5144 cells also gave a negative reaction with flagellar reagent from B. t. strain EG4961, a novel coleopteran-active strain that has been discovered to exhibit Diabrotica toxicity.
These results indicate that B. t. strain EG5144 is not a kurstaki, morrisoni or tolworthi-type B. t. strain.
Furthermore, the flagellar serotype of B. t. strain EG5144, which is yet not known, is apparently different from that of B. t. strain EG4961, which has been serotyped as serovar kumamotoensis (serotype 18). Both B. t. strain EG5144 and B. t. strain EG4961 appear to have flagellar serotypes that are different from those of other coleopteran-toxic B. t. strains reported in the literature.
Example 3
Size Fractionation and cryIIIB Probing of Native Plasmids of EG5144
B. t. strains may be characterized by fractionating their plasmids according to size by the well-known
procedure of agarose gel electrophoresis. This procedure involves lysing B. t. cells with lysozyme and SDS,
electrophoresing plasmids from the lysate through an agarose gel and staining the gel with ethidium bromide to visualize the plasmids. Larger plasmids, which move more slowly through the gel, appear at the top of the gel and smaller plasmids appear toward the bottom of the gel.
The agarose gel in Figure 2 shows that B.t. strain EG5144 contains native plasmids of approximately 145, 92, 12, 10 and 5.5 MDa, as indicated by the white horizontal bands. Plasmid sizes were estimated by comparison to plasmids of known sizes (not shown). Although not shown on Figure 2, B. t. strain EG5145 contains native plasmids of approximately 145, 92, 12 and 5.5 MDa. The cryptic 10 MDa plasmid found in B. t. strain EG5144 is not present in B. t. strain EG5145.
Figure 2 further shows that the coleopteran-toxic B. t. strain EG4961 contains native plasmids of about 150, 95, 70, 50, 5 and 1.5 MDa and that the coleopteran-toxic B. t. strain EG2838 contains native plasmids of about 100, 90 and 37 MDa. Figure 2 also shows that the coleopteran- toxic B. t. strain EG2158 contains native plasmids of about 150, 105, 88, 72, and 35 MDa. Some of the plasmids, such as the 150 and 1.5 MDa plasmids of B. t. strain EG4961 and the 150 MDa plasmid of B. t. strain EG2158, may not be visible in the photograph, although they are visible in the actual gel. Figure 2 demonstrates that the sizes of the native plasmids of B. t. strain EG5144 are different from the sizes of the native plasmids of B. t. strains EG2158, EG2838 and EG4961. B. t. strain EG5144 is
therefore distinct from the other coleopteran-toxic B. t. strains EG2158, EG2838 and EG4961, based on these plasmid array studies and on the serotyping studies described in Example 2. Likewise, B. t. strain EG5145 appears distinct from the coleopteran-toxic B. t. strains noted above based on plasmid array studies.
The plasmids shown in Figure 2 were transferred by blotting from the agarose gel to a nitrocellulose filter using the blot techniques of Southern, J.Molec.Biol . , 98 , pp.503-517 (1975), and the filter was hybridized as described above with the radioactively labeled 2.4 kb cryIIIB DNA probe. After hybridization, the filter was exposed to X-ray film. Examination of the X-ray film confirmed that the cryIIIB probe specifically hybridized to the 92 MDa plasmid of B. t. strain EG5144. This result demonstrates that the 92 MDa plasmid of B. t. strain EG5144 contains a DNA sequence that is at least partly homologous to the cryΙIIB gene and confirms that the 92 MDa plasmid contains a cryIII-type gene. The X-ray film also showed that the cryΙIIB probe hybridized, as expected, to the 95 MDa plasmid of B. t. strain EG4961 and to. the 100 MDa plasmid of B. t. strain EG2838, and to the 88 MDa plasmid of B. t. strain EG2158. The 88 MDa plasmid of B. t. strain EG2158 has been previously shown to contain the
coleopteran-toxin cryΙIIA gene (see Donovan et al., Mol . Gen. Genet. , 214 , pp.365-372 (1988)). The inventors have previously determined that the 100 MDa plasmid of B. t. strain EG2838 contains the coleopteran toxin cryIIIB gene and that the 95 MDa plasmid of B. t. strain EG4961 contains the novel coleopteran toxin cryΙIIC(a) gene.
Example 4
Blot Analysis of DNA from B. t. Strains EG5144 and EG5145
Both chromosomal and plasmid DNA (total DNA) from B. t. strain EG5144 were extracted and digested with separate restriction enzymes, SspI , HindIII and EcoRI. The digested DNA was size fractionated by electrophoresis through an agarose gel, and the fragments were then visualized by staining with ethidium bromide. For
comparison, total DNA from the coleopteran-toxic B. t.
strains EG2158, EG2838 and EG4961 was processed in an identical manner. Examination of the resultant stained agarose gel showed that restriction digestions of total DNA from these B. t. strains with each of SspI , HindIII and EcoRI yield hundreds of DNA fragments of various sizes.
The size fractionated DNA restriction fragments were transferred by blotting from the agarose gel to a
nitrocellulose filter and were then probed with a cryIII-type DNA hybridization probe. The filter was hybridized at 65°C in a buffered aqueous solution containing a radioactively labeled 2.4 kb cryIIIB DNA probe. After hybridization, the filter was exposed to X-ray film to make an autoradiogram. Figure 3 is a photograph of the autoradiogram where the numbers to the left indicate the size, in kb, of the DNA fragments of B.t. strain EG5144 that hybridized to the cryIIIB probe. These sizes were determined by comparison with the lane labeled "stnd" which contained phage lambda DNA digested with HindIII and radioactively labelled as size markers. Lanes in Figure 3 marked EG2158, EG5144, EG2838 and EG4961 contain size fractionated DNA fragments from these respective B. t.
strains, obtained by digestion with the restriction enzyme designated above the individual lanes.
In the lanes for each B. t strain in Figure 3, the dark bands represent DNA restriction fragments that hybridized with the cryΙIIB probe. Visual inspection of Figure 3 shows that the sizes of the cryJJJB-hybridizing restriction fragments of B. t. strain EG5144 are distinctly different from the sizes of the cryIIIB-hybridizing fragments of B. t. strains EG2158, EG2838 and EG4961.
In particular, the size of the cryIIIB-hybridizing SspI restriction fragment for B. t. strain EG5144 is 3.4 kb, and this is unlike the corresponding Sspl restriction fragments for the other three B. t. strains: 2.8 kb for B. t. strain EG2158; 2.4 kb for B. t. strain EG2838; and 4.5 and 6.0 kb for B. t. strain EG4961. Similar differences are apparent for the DNA restriction fragments obtained using HindIII and EcoRI. These restriction pattern results suggest that B. t. strain EG5144 contains a cry III-type gene that is
different from the cryIIIA, cryIIIB and cryΙIIC(a) genes of B. t. strains EG2158, EG2838 and EG4961, respectively. The cryIII-type gene of B. t. strain EG5144 has been designated cryIIIC(b; (SEQ ID NO:1) by the inventors.
Total DNA from B. t. strain EG5144 and B. t. strain EG5145 was extracted and digested with six separate restriction enzymes (HindIII, EcoRI , AccI, DraI , SspI , Xbal) , and size fractionated by electrophoresis on an agarose gel. The size fractionated DNA restriction fragments were then transferred by blotting to a
nitrocellulose filter and were then probed with a cryIII-type DNA hybridization probe, specifically a probe
containing cryIIIA. After hybridization, the filter was exposed to X-ray film to make an autoradiogram. The restriction pattern results were identical for the two B. t. strains evaluated, EG5144 and EG5145, which suggests that the two strains contain the same cryIII-type gene.
Example 5
Characterization of Crystal Proteins of B. t. Strain EG5144
B. t. strain EG5144 was grown in DSMG sporulation medium at room temperature (about 21-25°C) until
sporulation and cell lysis had occurred (4 to 5 days growth). The DSMG medium is 0.4% (w/v) Difco nutrient broth, 25 mM K2HPO4, 25 mM KH2PO4, 0.5 mM Ca(NO3)2, 0.5 mM MgSO4, 10 μM FeSO4, 10 μM. MnCl2 and 0.5% (w/v) glucose. The sporulated culture of B. t. strain EG5144 was observed microscopically to contain free floating, irregularly shaped crystals in addition to B. t. spores. Experience has shown that B. t. crystals are usually composed of proteins that may be toxic to specific insects. The appearance of the crystals of B. t. strain EG5144 differed from the flat, rectangular (or rhomboidal) crystals of B. t. strain EG2158, but partially resembled some of the irregularly shaped crystals of B. t. strains EG2838 and EG4961.
Spores, crystals and residual lysed cell debris from the sporulated culture of B. t. strain EG5144 were
harvested by centrifugation. The recovered solids were washed once with aqueous IN NaCl and twice with TETX (containing 10 mM Tris HC1 pH 7.5, ImM EDTA and 0.005% (w/v) Triton® x-100) and suspended in TETX at a
concentration of 50 mg/ml. The washed crystals were specifically solubilized from 250 μg centrifuged
fermentation culture solids (containing crystals, spores and some cell debris) by heating the solids mixture in a solubilization buffer (0.14 M Tris pH 6.8, 2% (w/v) SDS, 5% (v/v) 2-mercaptoethanol, 10% (v/v) glycerol and 0.1% (v/v) bromophenol blue) at 100°C for 5 minutes. The solubilized crystal proteins were size fractionated by SDS-PAGE. After size fractionation, the proteins were visualized by staining with Coomassie dye. Cultures of B.t. strains EG4961, EG2158 and EG2838 were processed in an identical manner for purposes of comparison.
Figure 4 shows the results of this protein size fractionation analysis where the numbers to the left indicate the size, in kDa, of the crystal proteins
synthesized by B. t. strain EG5144. As shown in lane 1, a major protein of approximately 70 kDa and a minor protein of approximately 30 kDa were solubilized from centrifuged fermentation solids containing B. t. strain EG5144 spores and crystals. The approximately 70 kDa protein of B. t. strain EG5144 appears similar in size to the approximately 70 kDa coleopteran-toxic crystal proteins of B. t. strains EG4961 (lane 2), EG2158 (lane 3) and to the approximately 74 kDa coleopteran-toxic crystal protein of B. t. strain EG2838 (lane 4).
Previous work by the inventors has shown that the coleopteran-toxic crystal proteins of B. t. strains EG4961, EG2158 and EG2838 are each different. The CryIIIC(a) protein of B. t. strain EG4961 is coded by the cryΙIIC(a) gene and has a deduced size of 74,393 Da. The CryIIIA protein of B. t. strain EG2158 is coded by the cryIIIA gene and has a deduced size of 73,116 Da. The CryIIIB protein of B. t. strain EG2838 is coded by the cryIIIB gene and has a deduced size of 74,237 Da. As described in Example 6, the coleopteran-toxic crystal protein of B. t. strain
EG5144 produced by the novel cryIIIC(b) gene (SEQ ID NO:1) is clearly different from the CryIIIA, CryIIIB and
CryIIIC(a) proteins.
The minor crystal protein of approximately 30 kDa that is produced by B. t. strain EG5144 is roughly similar in size to small crystal proteins produced by B. t. strains EG4961, EG2158 and EG2838. The approximately 30 kDa minor proteins of B. t. strains EG2158, EG2838 and EG4961 appear to be related to each other and none has been found to exhibit measurable insecticidal activity towards
coleopteran insects. There is no reason to believe that the approximately 30 kDa protein of B. t. strain EG5144 possesses insecticidal activity against coleopteran insects.
Following the procedure of Example 4, further DNA blot analysis revealed that the 2.4 kb cryIIIB DNA probe specifically hybridized to a single 7.0 kb EcoRI-XbaI restriction fragment of B. t. strain EG5144 DNA. This result suggested that the 7.0 kb fragment contained the complete cryΙIIC(b) gene.
The 7.0 kb EcoRI-XbaI fragment of B. t. strain EG5144 was isolated and studies were conducted on the 7.0 kb EcoRI-XbaI restriction fragment to confirm that the fragment contained a cryIII-type gene, in particular, the cryΙIIC(b) gene. The procedures set forth in Example 6 describe the determination of the nucleotide base sequence of the cryΙIIC(b) gene (SEQ ID NO:1). Example 6
Cloning and Seguencing of the cryIIIC(b) Gene of B. t. Strain EG5144
In order to isolate the 7.0 kb EcoRI-Xbal fragment described in the previous Example, a plasmid library of B. t. strain EG5144 was constructed by ligating size- selected DNA EcoRI-XbaI restriction fragments from B. t. strain EG5144 into the well-known E. coli vector pUC18. This procedure involved first obtaining total DNA from B. t. strain EG5144 by cell lysis followed by DNA spooling, then double digesting the total DNA with both EcoRI and XbaI restriction enzymes, electrophoresing the digested DNA through an agarose gel, excising a gel slice
containing 4-10 kb size selected fragments of DNA, and electroeluting the size selected EcoRI-XbaI restriction fragments from the agarose gel slice. These fragments were mixed with the E. coli plasmid vector pUC18, which had also been digested with EcoRI and XbaI. The pUC18 vector carries the gene for ampicillin resistance (Ampr) and the vector replicates in E. coli . T4 DNA ligase and ATP were added to the mixture of size-selected restriction
fragments of DNA from B. t strain EG5144 and of digested pUC18 vector to allow the pUC18 vector to ligate with the B. t. strain EG5144 restriction fragments.
The plasmid library was then transformed into E. coli cells, a host organism lacking the gene of interest, as follows. After ligation, the DNA mixture was incubated with an ampicillin sensitive E. coli host strain, E. coli strain DH5α, that had been treated with CaCl2 to allow the cells to take up the DNA. E. coli, specifically strain DH5α, was used as the host strain because these cells are easily transformed with recombinant plasmids and because E. coli strain DH5α does not naturally contain genes for B. t. crystal proteins. Since pUC18 confers resistance to ampicillin, all host cells acquiring a recombinant plasmid would become ampicillin resistant. After exposure to the recombinant plasmids, the E. coli host cells were spread on agar medium that contained ampicillin. After
incubation overnight at a temperature of 37°C, several thousand E. coli colonies grew on the ampicillin-containing agar from those cells which harbored a
recombinant plasmid. These E. coli colonies were then blotted onto nitrocellulose filters for subsequent
probing.
The radioactively labeled 2.4 kb cryΙIIB gene was then used as a DNA probe under conditions that permitted the probe to bind specifically to those transformed host colonies that contained the 7.0 kb EcoRI-XbaI fragment of DNA from B. t. strain EG5144. Several E. coli colonies specifically hybridized to the 2.4 kb cryIIIB probe. One cryIIIB-hybridizing colony, designated E. coli strain EG7236, was studied further. E. coli strain EG7236 contained a recombinant plasmid, designated pEG271, which consisted of pUC18 plus the inserted EcoRI-XbaI
restriction fragment of DNA from B. t. strain EG5144 of approximately 7.0 kb. The cryIIIB probe specifically hybridized to the 7.0 kb DNA fragment insert in pEG271. A restriction map of pEG271 is shown in Figure 5.
The 7.0 kb fragment of pEG271 contained HindIII fragments of 2.4 kb and 3.8 kb, and a BamHI-Xbal fragment of 4.0 kb that specifically hybridized with the cryIIIB probe. The 2.4 kb HindIII fragment was subcloned into the DNA sequencing vector M13mp18. The 4.0 kb BamHI -XbaI fragment was subcloned into the DNA sequencing vectors M13mp18 and M13mp19.
The nucleotide base sequence of a substantial part of each subcloned DNA fragment was determined using the standard Sanger dideoxy method. For each subcloned fragment, both DNA strands were sequenced by using
sequence-specific 17-mer olignucleotide primers to
initiate the DNA sequencing reactions. Sequencing
revealed that the 7.0 kb fragment contained an open reading frame and, in particular, a new cryIII-type gene. This new gene, designated cryIIIC(b) (SEQ ID NO:1), is significantly different from the cryIIIA gene. As
indicated below, the cryΙIIC(b) gene is also clearly distinct from the cryΙIIB gene.
The DNA sequence of the cryΙIIC(b) gene (SEQ ID NO:1) and the deduced amino acid sequence of the CryIIIC (b) protein (SEQ ID NO : 2 ) encoded by the cry IΙIC (b) gene are shown in Figure 1. The protein coding portion of the cry IΙIC (b) gene (SEQ ID NO:1) is defined by the nucleotides starting at position 144 and ending at position 2099. The probable ribosome binding site is indicated as "RBS" in Figure 1-1. The size of the
CryIIIC(b) protein (SEQ ID NO: 2) encoded by the cryIΙIC(b) gene, as deduced from the open reading frame of the cryΙIIC(b) gene (SEQ ID NO:1), is 74,265 Da (652 amino acids). It should be noted that the apparent size of the CryIIIC(b) protein, as determined from SDS-PAGE, is approximately 70 kDa. Therefore, the CryIIIC(b) protein (SEQ ID NO:2) will be referred to in this specification as being approximately 70 kDa in size.
The size of the prior art CryIIIA protein has
previously been deduced to be 73,116 Da (644 amino acids). The size of the CryIIIB protein has previously been determined to be 74,237 Da (651 amino acids).
DNA sequencing revealed the presence of a HindIII restriction site within the cryΙIIC(b) gene and a Sspl restriction site downstream of the cryΙIIC(b) gene (See Figures 1-2 and 1-3 respectively). Knowledge of the locations of these restriction sites permitted the precise determination of the location and orientation of the cryΙIIC(b) gene within the 7.0 kb fragment as indicated by the arrow in Figure 5.
The computer program of Korn and Queen (L.J. Korn and C. Queen, "Analysis of Biological Sequences on Small
Computers," DNA, 3 , pp. 421-436 (19δ4)) was used to compare the sequences of the cryΙIIC(b) gene (SEQ ID NO:1) to the cryIIIB and cryIIIA genes and to compare the deduced amino acid sequences of their respective
CryIIIC (b), CryIIIB and CryIIIA proteins.
The nucleotide base sequence of the cryΙIIC(b) gene (SEQ ID NO:1) was 96% positionally identical with the nucleotide base sequence of the cryΙIIB gene and only 76% positionally identical with the nucleotide base sequence of the cryIIIA gene. Thus, although the cryΙIIC(b) gene (SEQ ID NO:1) is related to the cryIIIB and cryIIIA genes, it is clear that the cryIΙIC (b) gene is distinct from the cryIIIB gene and substantially different from the cryIIIA gene.
The deduced amino acid sequence of the CryIIIC(b) protein (SEQ ID NO: 2) was found to be 95% positionally identical to the deduced amino acid sequence of the
CryIIIB protein, but only 68% positionally identical to the deduced amino acid sequence of the CryIIIA protein. These differences, together with the differences in insecticidal activity as set forth below, clearly show that the CryIIIC(b) protein encoded by the cryΙIIC(b) gene (SEQ ID NO:1) is a different protein from the CryIIIB protein or the CryIIIA protein.
Moreover, while not wishing to be bound by any theory, based on a comparison of the amino acid sequences of the CryIIIC(b) protein (SEQ ID NO: 2) with other CryIII-type proteins known to the inventors, it is believed that the following amino acid residues may be of significance for the enhanced corn rootworm toxicity of the CryIIIC(b) protein, where the numbers following the accepted
abbreviations for the amino acids indicate the position of the amino acid in the sequence illustrated in Figure 1 and identified in SEQ ID NO: 2: His9, His231, Gln339, Ser352, Asn446, His449, Val450, Gly451, Ile600 and Thr624. These amino acid residues were selected as being of probable significance for the corn rootworm toxicity of the
CryIIIC(b) protein (SEQ ID NO:2) because, after studying the amino acid sequences of several other CryIII proteins, the amino acids at the indicated positions fairly
consistently showed different amino acids than those indicated for the CryIIIC(b) protein.
Based on the same studies, it is also believed that site directed mutagenesis of the cryΙIIC(b) gene (SEQ ID NO:l) may result in improved or enhanced corn rootworm toxicity for the resultant protein where one or more of the following amino acid modifications are effected:
Pro21 to Gly; Asp97 to Asn; Val289 to lie; Ser352 to Phe; 417Ile to Val; Phe419 to Leu; Gly451 to Ser; Ile590 to Leu; Ile600 to Lys; Thr624 to Lys.
As is well understood in the art, other changes in the cryΙIIC(b) gene (SEQ ID NO:1) may be made, via site directed mutagenesis or gene truncation or the like, that could yield a toxic protein which possesses essentially similar insecticidal activity (to corn rootworm and other coleopteran insects) as that exhibited by the CryIIIC(b) protein (SEQ ID NO: 2). Modifications to the cryIΙIC (b) gene (SEQ ID NO:1) and CryIIIC(b) protein (SEQ ID NO:2) such as described above are intended to be within the scope of the claimed invention.
Example 7
Expression of the Cloned cryIIIC(b) Gene Studies were conducted to determine the production of the CryΙIIC(b) protein (SEQ ID NO: 2) by the cryIIIC(b) gene (SEQ ID NO:1).
Table 2 summarizes the relevant characteristics of the B. t. and E. coli strains and plasmids used during these procedures. A plus (+) indicates the presence of the designated element, activity or function and a minus (-) indicates the absence of the same. The designations s and r indicate sensitivity and resistance, respectively, to the antibiotic with which each is used. The
abbreviations used in the Table have the following
meanings: Amp (ampicillin); Cm (chloramphenicol); Cry (crystalliferous); Tc (tetracycline).
Table 2
Strains and Plasmids
Strains Relevant characteristics
B. thuringiensis
HD73-26 Cry-, Cms
EG7237 HD73-26 harboring pEG272 ( cryIIIC (b) +) EG5144 cryIIIC(b) +
E. coli
DH5α Cry-, Amps
GM2163 Cry-, Amps
EG7236 DH5α harboring pEG271 (cryIIIC(b)+) Plasmids
pUC18 Ampr, Cry-, E. coli vector pNN101 Cmr, Tcr, Cry-, Bacillus vector pEG271 Ampr, cryIIIC(b) + E. coli
recombinant plasmid consisting of the 7.0 kb EcoRI-Xbal cryIIIC(b)+ fragment of B. t. strain EG5144 ligated into the EcoRI-Xbal sites of pUC18
pEG272 Tcr, Cmr, cryIIIC(b)+ Bacillus-E.
coli recombinant plasmid
consisting of the Bacillus vector pNN101 ligated into the SphI site of pEG271.
E. coli cells harboring plasmid pEG271 described in Example 6 were analyzed and found not to produce
detectable amounts of the 70 kDa CryIIIC(b) crystal protein.
Experience has shown that cloned B. t. crystal genes are poorly expressed in E. coli and highly expressed in B. t. from their respective native promoter sequences. Recombinant plasmid pEG271, constructed as set forth in Example 6 and shown in Figure 5, will replicate in E.
coli , but will not replicate in B. t. To achieve a high level of expression of the cloned cryΙIIC(b) gene, the Bacillus vector pNN101 (Tcr Cmr Cry-) that is capable of replicating in B. t. was ligated into the SphI site of pEG271. The resultant plasmid was designated pEG272.
Details of the construction of plasmid pEG272 and its subsequent use to transform B. t. are described below.
The isolated plasmid pEG271 DNA was digested with SphI and was then mixed with the Bacillus vector pNN101 that had also been digested with Sphl . T4 DNA ligase and ATP were added to the mixture to allow pEG271 to ligate into the SphI site of the pNN101 vector.
After ligation, the DNA mixture was added to a suspension of E. coli strain DH5α cells that had been treated with calcium chloride to permit the cells to take up plasmid DNA. After exposure to the recombinant
plasmids, the E. coli host cells were spread on an agar medium containing tetracycline. Only cells that had taken up a plasmid consisting of pEG271 ligated into the SphI site of pNN101 would grow on the tetracycline agar medium whereas cells that had not absorbed the plasmid would not grow.
Plasmid was isolated from one tetracycline resistant colony, digested with SphI, and electrophoresed through an agarose gel. The plasmid consisted of two SphI DNA fragments of 5.8 kb and 9 kb corresponding to plasmids pNN101 and pEG271, respectively. This plasmid was
designated pEG272. A restriction map of pEG272 is shown in Figure 6. Plasmid pEG272 was then used to transform cells of E. coli strain GM2163 made competent by the calcium chloride procedure described earlier in Example 6. E. coli strain GM2163 is a crystal negative (Cry-) and ampicillin sensitive (Amps) strain, constructed by the procedures of M.G. Marinus et al. in Mol. Gen. Genet., 192 , pp.28δ-2δ9 (1983).
Plasmid pEG272 was then isolated from the transformed E. coli strain GM2163, using the procedures described above. The isolated plasmid pEG272 was next transformed by electroporation into B. t. strain HD73-26. Cells of B. t. strain HD73-26 are crystal-negative (Cry-) and chloramphenicol sensitive (Cms). Using a BioRad Gene
Pulser apparatus to carry out the electroporation, cells of B. t. strain HD73-26 in suspension were induced to take up pEG272 which was also added to the mixture.
After electroporation, the transformed B. t. cells were spread onto an agar medium containing 5 μg
chloramphenicol and were incubated about 16-18 hours at 30°C. Cells that had taken up plasmid pEG272 would grow into colonies on the chloramphenicol agar medium whereas cells that had not absorbed the plasmid would not grow. One Cmr colony, designated B. t. strain EG7237, contained a plasmid whose restriction pattern appeared identical to that of pEG272.
Cells of B.t. strain EG7237 were grown in a
sporulation medium containing chloramphenicol (3 μg/ml) at 22-25°C until sporulation and cell lysis had occurred (4-5 days). Microscopic examination revealed that the
sporulated culture of B. t. strain EG7237 contained spores and small free floating irregularly shaped crystals.
These crystals resembled the small, irregularly-shaped crystals observed with a sporulated culture of B. t. strain EG5144 that had been prepared in a similar manner.
Spores, crystals and cell debris from the sporulated fermentation culture of B. t. strain EG7237 were harvested by centrifugation. The centrifuge pellet was washed once with IN aqueous NaCl and twice with TETX (10 mM Tris·HCl pH 7.5, 1 mM EDTA, 0.005% (w/v) Triton® X-100), and the pellet suspended in TETX at a concentration of 50 mg pellet/ml TETX.
The crystals in the centrifuge pellet suspension were solubilized by heating a portion of the centrifuge
suspension (containing 250 μg pellet solids) in
solubilization buffer (0.14 M Tris pH 6.8, 2% (w/v) SDS, 5% (v/v) 2-mercaptoethanol, 10% (v/v) glycerol and 0.1% (w/v) bromophenol blue) at 100°C for 5 minutes. After crystal solubilization had occurred, the mixture was applied to an SDS-polyacryamide gel and the solubilized proteins in the mixture were size fractionated by electrophoresis. After size fractionization, the proteins were visualized by staining with Coomassie dye. A
photograph of the Coomassie stained gel is shown in Figure 7.
Lane 3 of the gel in Figure 7 shows that B. t. strain EG7237 produced a major protein of approximately 70 kDa and a minor protein of approximately 30 kDa. These proteins appeared to be identical in size with the major approximately 70 kDa protein and the minor approximately 30 kDa protein produced by B. t. strain EG5144, which are shown in the lane 1 of Figure 7 and which were prepared in a manner identical to B. t. strain EG7237. This result indicates that the 7.0 kb fragment of pEG272 contains two crystal protein genes: one for the approximately 70 kDa protein and one for the approximately 30 kDa protein.
The gene encoding the approximately 70 kDa protein is the cryIIIC (b) gene, and its encoded protein is the insecticidal CryIIIC(b) protein. The DNA sequence for the cryΙIIC(b) gene (SEQ ID NO:1) and the amino acid sequence for its corresponding deduced protein (SEQ ID NO:2) are shown in Figure 1.
B.t. strain EG7237 produced approximately three times more 70 kDa protein, on a weight basis, than did B. t.
strain EG5144, as is evident from the protein bands in Figure 7. Production of the minor 30 kDa protein in recombinant B. t. strain EG7237 was also increased, as compared with B. t. strain EG5144. The following Examples 8-11 describe the manner in which the insecticidal activities of B. t. strain EG5144, B. t. strain EG7237, and the CryIIIC(b) protein made by these strains were determined.
Example 8
Insecticidal Activity of B. t. strain EG7237 and its CryIIIC(b) Protein Against Southern Corn Rootworm and Colorado Potato Beetle
The insecticidal activity of recombinant B. t. strain EG7237, which contains the cryΙIIC (b) gene (SEQ ID NO:1) that produces the CryIIIC(b) toxin protein (SEQ ID NO: 2), was determined against southern corn rootworm (Diabrotica undecimpunctata howardi) and Colorado potato beetle
(Leptinotarsa decemlineata) .
For comparison, two other recombinant B. t. strains containing cry IIJ-type toxin genes in a B. t. strain HD73-26 background were also included in the bioassay study. These were recombinant B. t. strain EG7235, which contains the cryIIIA gene that produces the CryIIIA toxin protein, and recombinant B. t. strain EG7225, which contains the cryIIIB gene that produces the CryIIIB toxin protein.
The three B. t. strains were grown in liquid
sporulation media at 30°C until sporulation and cell lysis had occurred. The fermentation broth was concentrated by microfiltration. The concentrated fermentation broth was then freeze dried to prepare a B. t. powder suitable for insect bioassay. The amount of CryIII-type toxin protein in each of the B. t. powders was quantified using standard SDS-PAGE techniques.
First instar southern corn rootwom larvae were bioassayed via surface contamination of an artificial diet similar to Marrone et al., J.Econ.Entomol. , 78, pp.290-293 (1985), but without formalin. Each bioassay consisted of eight serial aqueous dilutions with aliquots applied to the surface of the diet in a bioassay tray. Each 2 ml well of the bioassay tray contained 1 ml diet having a surface area of 175 mm2. After the diluent (an aqueous 0.005% Triton® X-100 solution) had evaporated, the insect larvae were placed on the diet and incubated at 28°C.
Thirty-two larvae were tested per dose. Mortality was scored after 7 days. A control, consisting of diluent only, was also included in the bioassay study.
First instar Colorado potato beetle larvae were tested using similar techniques, except for the
substitution in the artificial diet of BioServe's No. 9830 insect diet with potato flakes added. Thirty-two larvae were tested per dose, and mortality was scored at three days instead of seven days.
The results of the bioassay study are shown below in
Table 3, where insecticidal activity is reported as PLC50 values, the concentration of CryIII-type protein required to kill 50% of the insects tested. Four replications per dose were used in the bioassay studies for both insects tested. Data from each of the replicated bioassays were pooled for probit analysis (R.J. Daum,
Bull . Entomol. Soc . Am . , 16 , pp.10-15 (1970)) with mortality corrected for control death, the control being the diluent only (W.S. Abbott, J.Econ.Entomol . , 18 , pp.265-267
(1925)). Results are shown as the dose amount of CryIII-type protein (in ng CryIII protein per mm2 of diet
surface) resulting in PLC50. Confidence intervals, at 95%, are given within parentheses below the PLC50 values.
Table 3
Insecticidal Activity of Recombinant B. t. strains EG7237. EG7235 and EG722S
Southern Corn Rootworm Colorado Potato Beetle
CryIII Protein
Concentration PLC 50 PLC50
B. t. Strain CrvIII Protein (%) (ng CryIII protein/mm2) (ng CryIII protein/mm-2)
B.t. EG7237 CryΙIIC(b) 7.2 1548 6.92
(1243-1992) (5.15 - 9.10)
B. t . EG7235 CryIIIA 28.4 6% control 0.34
at 4570 (0.30 - 0.39)
B. t. EG7225 CryIIIB 9.4 20% control 1.26
at 4570 (1.07 - 1.46)
The results of this bioassay study demonstrate that B. t. strain EG7237 which produces the CryIIIC(b) toxin protein (SEQ ID NO: 2) is insecticidal to southern corn rootworm. In contrast, the CryIIIA and CryIIIB toxin proteins of B. t. strains EG7235 and EG7225, respectively, appear to have no measurable activity against this insect at the highest dose level tested.
All three of the B. t. strains exhibit insecticidal activity against Colorado potato beetle larvae, with the CryIIIA toxin protein of B. t. strain EG7235 being
significantly more potent than the CryIIIC (b) toxin protein (SEQ ID NO:2) of B. t. strain EG7237 and with the CryIIIB toxin protein of B. t. strain EG7225 having
insecticidal activity falling between that shown for
CryIIIA and CryIIIC(b).
These results suggest that the insecticidal activity of specific CryIII-type toxin proteins varies for
different insect genera within the order Coleoptera. Example 9
Insecticidal Activity of B. t. strain EG7237 and its cryIIIC(b) Protein Against Mexican Bean Beetle
The insecticidal activity of recombinant B. t. strain EG7237, evaluated in Example 8, was also determined against Mexican bean beetle (Epilachna varivestis) . As in Example 8, recombinant B. t. strains EG7235 and EG7225 were included for comparison, and all B. t. powders were prepared as in Example 8.
First instar Mexican bean beetle larvae were
bioassayed by a leaf dip procedure, since a suitable artificial diet is not available for this insect. Soybean leaves were dipped into known treatment concentrations of the B. t. powder suspended in an aqueous 0.1% Triton® X-100 solution. After excess material had dripped off, the leaves were allowed to dry. Leaves dipped in 0.1% Triton® X-100 served as untreated controls. Twenty insect larvae were confined to a petri dish with treated leaves,
incubated at 25°C, and allowed to feed for three days, at which time mortality was scored.
The results of the bioassay study are shown below in Table 4, where insecticidal activity is reported as PLC50 values, the concentration of CryIII-type protein required to kill 50% of the insects tested. The data were handled as described in Example 8, for Table 3. Results are shown as the dose amount of CryIII-type protein (in mg CryIII protein/ml solution used in the leaf dip) resulting in PLC50. Confidence intervals, at 95%, are given within parentheses following the PLC50 values. Table 4
Insecticidal Activity of B. t. Strains EG7237, EG7235 and
EG7225 Against Mexican Bean Beetle
CryIII No. of PLC50
B.t. Strain Protein Replications (mg CryIIIprotein/ml)
B. t. EG7237 CryIIIC(b) 4 4.2 (2.5-6.5)
B. t. EG7235 CryIIIA 4 16% control at 60
B. t. EG7225 CryIIIB 4 51.8 (31-209)
The results of this bioassay study demonstrate that B. t. strain EG7237 which produces the CryΙIIC(b) toxin protein (SEQ ID NO: 2) is significantly more insecticidal to Mexican bean beetle than the CryIIIB-producing B. t. strain EG7225. B. t. strain EG7235 which produces CryIIIA toxin protein exhibited no measurable insecticidal activity at the highest dose tested.
These results are further evidence that the
insecticidal activity of specific CryIII-type toxin proteins varies widely for insect genera within the order Coleoptera.
Example 10
Insecticidal Activity of B. t. Strain EG5144
Against Southern corn Rootworm
The insecticidal activity of B. t. strain EG5144 was evaluated against Southern corn rootworm (Diabrotica undecimpunctata howardi ). For comparison, B. t. strain EG4961 which produces the CryIIIC(a) toxin protein was included in the bioassay study.
The bioassay procedure for southern corn rootworm in this Example determined PLC50 values, the concentration of CryIII-type protein required to kill 50% of the insects tested. The procedure was similar to the artificial diet bioassay carried out in the previous Example, using thirty-two first instar southern corn rootworm larvae per dose. Data from each of the replicated bioassays were pooled for probit analysis (R.J. Daum,
Bull. Entomol .Soc. Jim., 16, pp.10-15 (1970)) with mortality corrected for control death, the control being the diluent only (W.S. Abbott, J.Econ.Entomol. , 18 , pp.265-267
(1925) ) . Results are reported for two separate tests as the dose amount of CryIII-type protein (ng CryIII protein per mm2 of diet surface) resulting in PLC50. Confidence intervals, at 95%, are given within parentheses following the PLC50 values. In Test 1 four replications per dose were used, and in Test 2, carried out at a later date, two replications were used.
The B. t. strains used in this Example were prepared as described for the B. t. strains in Example 8, except that the fermentation broth was concentrated by
centrifugation.
The results of this bioassay study with southern corn rootworm are shown below in Table 5. Table 5
Insecticidal Activity of B.t. strains EG5144 and EG4961 Against Southern Corn Rootworm CryIII Protein PLC50
Concentration (ng CryIII B. t. Strain CryIII Protein ( %) protein/mm2)
B. t. EG5144 CryΙIIC(b) Test 1: 4.0 944 (690-1412)
Test 2: 6.4 1145 (773-2185) B. t. EG4961 CryΙIIC(a) Test 1: 11.6 102 (66-119)
Test 2: 11.6 165 (121-220)
This bioassay study demonstrates that both B. t. strain EG5144 and B. t. strain EG4961, which produce CryIIIC-type proteins, provide quantifiable insecticidal activity against southern corn rootworm.
Example 11
Insecticidal Activity of B. t. Strain EG5144
Against Japanese Beetle Larvae
The insecticidal activity of B. t. strain EG5144 was evaluated against Japanese beetle larvae, also known as white grubs (Popillia japonica) . For comparison, B. t. strain EG4961 which produces the CryIIIC(a) toxin protein was included in the bioassay study, as were B. t. strain EG215δ which produces the CryIIIA toxin protein and B. t. strain EG2δ3δ which produces the CryIIIB toxin protein.
The bioassay procedure in this Example was a
screening assay, at a single dose of CryIII-type protein in a diet incorporation assay (1 mg CryIII-type protein per ml diet). B. t. powder to be tested, suspended in a diluent (an aqueous 0.005% Triton® X-100 solution) was incorporated into 100 ml of hot (50°-60°C), liquid
artificial diet (based on the insect diet described by Ladd, Jr. in J.Econ.Entomol . , 79 , pp.666-671 (19δ6)). The mixture was allowed to solidify in petri dishes, and one 19 mm diameter plug of this material then placed in each well of a plastic ice cube tray. One grub was introduced per well of the trays, the wells were covered with moist germination paper overlaid with aluminum foil, and the trays were held at 25°C for seven days before mortality was scored. The insects tested were third instar Japanese beetle grubs. Two replications of sixteen insects each were carried out in this study.
The results of this screening bioassay study are shown below in Table 6, where insecticidal activity is reported as percentage insect mortality, with the
mortality being corrected for control death, the control being diluent only incorporated into the diet plug.
Results were obtained at a single dose rate of CryIII-type protein: 1 mg CryIII-type protein per ml of diet;
percentage CryIII-type protein present in. the respective B. t. powders is also shown in Table 6. Table 6
Insecticidal Activity of B.t. strains EG5144, EG4961. EG2158 and EG2838
Against Japanese Beetle Grubs
CryI II-type Protein CryIII-type Protein Dose Insect in B.t. Powder (mg CryIII-type Mortality
B.t. Strain CryIII Protein (wt. %) protein/ml diet) (%)
B.t. EG5144 CryΙIIC(b) 5.4 1 62.5
B.t. EG4961 CryΙIIC(a) 18.0 1 9
B. t. EG2158 CryIIIA 14.0 1 44
B.t. EG2838 CryIIIB 7.2 1 48
The insecticidal performance against Japanese beetle grubs of B. t. strain EG5144 with its CryIIIC(b) toxin protein (SEQ ID NO: 2) is clearly superior to that of B. t. strain EG4961 with its CryIIIC(a) protein.
With respect to B. t. strains EG2158 and B. t. strain EG2838, B. t. strain EG5144 exhibited superior insecticidal performance against Japanese beetle grubs.
B. t. strain EG5145, whose characteristics are similar to those of B.t. strain EG5144, has been found to exhibit insecticidal activity against Japanese beetle grubs equivalent to that of B. t. strain EG5144, although the bioassay data are not presented in this Example 11.
Microorganism Deposits
To assure the availability of materials to those interested members of the public upon issuance of a patent on the present application, deposits of the following microorganisms were made prior to the filing of present application with the ARS Patent Collection, Agricultural Research Culture Collection, Northern Regional Research Laboratory (NRRL), 1815 North University Street, Peoria, Illinois 61604, as indicated in the following Table 7: Table 7
Bacterial Strain NRRL Accession No. Date of Deposit B. t. EG2158 B-18213 April 29, 1987 B. t. HD73-26 B-18508 June 12, 1989 B. t. EG2838 B-16603 February 8, 1990 B. t. EG5144 B-18655 May 22, 1990 B. t. EG7237 B-18736 October 17, 1990 E. coli EG7236 B-18662 June 6, 1990 B. t. EG5145 B-18920 November 21, 1991
These microorganism deposits were made under the provisions of the "Budapest Treaty on the International Recognition of the Deposit of Microorganisms for the Purposes of Patent Procedure". All restrictions on the availability to the public of these deposited
microorganisms will be irrevocably removed upon issuance of a patent based on this application. The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification as indicating the scope of the invention. SEQUENCE LISTING
(1) GENERAL INFORMATION:
(i) APPLICANT: Donovan, William P.
Rupar, Mark J.
Slaney, Annette C.
(ii) TITLE OF INVENTION: BACILLUS THURINGIENSIS cryIIIC(b) TOXIN
GENE AND PROTEIN TOXIC TO COLEOPTERAN INSECTS
(iii) NUMBER OF SEQUENCES: 2
(iv) CORRESPONDENCE ADDRESS:
(A) ADDRESSEE: Panitch Schwarze Jacobs & Nadel c/o A.S.
Nadel
(B) STREET: 1601 Market Street, 36th Floor
(C) CITY: Philadelphia
(D) STATE: Pennsylvania
(E) COUNTRY: U.S.A.
(F) ZIP: 19103
(v) COMPUTER READABLE FORM:
(A) MEDIUM TYPE: Floppy disk
(B) COMPUTER: IBM PC compatible
(C) OPERATING SYSTEM: PC-DOS/MS-DOS
(D) SOFTWARE: PatentIn Release #1.0, Version #1.25
(vi) CURRENT APPLICATION DATA:
(A) APPLICATION NUMBER:
(B) FILING DATE:
(C) CLASSIFICATION:
(vii) PRIOR APPLICATION DATA:
(A) APPLICATION NUMBER: US 07/649,562
(B) FILING DATE: 31-JAN-1991
(viii) ATTORNEY/AGENT INFORMATION:
(A) NAME: Egolf, Christopher
(B) REGISTRATION NUMBER: 27633
(C) REFERENCE/DOCKET NUMBER: 7205-29 PI
(ix) TELECOMMUNICATION INFORMATION:
(A) TELEPHONE: 215-757-1590
(2) INFORMATION FOR SEQ ID NO:1:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 2430 base pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: double
(D) TOPOLOGY: circular
(ii) MOLECULE TYPE: DNA (genomic)
(ix) FEATURE:
(A) NAME/KEY: CDS (B) LOCATION: 144..2099
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:l:
CCATATACAA CTTATCAGGA AGGGGGGGAT GCACAAAGAA GAAAAGAATA AGAAGTGAAT 60
GTTTATAATG TTCAATAGTT TTATGGGAAG GCATTTTATC AGGTAGAAAG TTATGTATTA 120
TGATAAGAAT GGGAGGAAGA AAA ATG AAT CCA AAC AAT CGA AGT GAA CAT 170
Met Asn Pro Asn Asn Arg Ser Glu His
1 5
GAT ACG ATA AAG GTT ACA CCT AAC AGT GAA TTG CCA ACT AAC CAT AAT 218 Asp Thr lie Lys Val Thr Pro Asn Ser Glu Leu Pro Thr Asn His Asn
10 15 20 25
CAA TAT CCT TTA GCT GAC AAT CCA AAT TCG ACA CTA GAA GAA TTA AAT 266 Gln Tyr Pro Leu Ala Asp Asn Pro Asn Ser Thr Leu Glu Glu Leu Asn
30 35 40
TAT AAA GAA TTT TTA AGA ATG ACT GAA GAC AGT TCT ACG GAA GTG CTA 314 Tyr Lys Glu Phe Leu Arg Met Thr Glu Asp Ser Ser Thr Glu Val Leu
45 50 55
GAC AAC TCT ACA GTA AAA GAT GCA GTT GGG ACA GGA ATT TCT GTT GTA 362 Asp Asn Ser Thr Val Lys Asp Ala Val Gly Thr Gly lie Ser Val Val
60 65 70
GGG CAG ATT TTA GGT GTT GTA GGA GTT CCA TTT GCT GGG GCA CTC ACT 410 Gly Gln He Leu Gly Val Val Gly Val Pro Phe Ala Gly Ala Leu Thr
75 80 85
TCA TTT TAT CAA TCA TTT CTT GAC ACT ATA TGG CCA AGT GAT GCT GAC 458 Ser Phe Tyr Gln Ser Phe Leu Asp Thr Ile Trp Pro Ser Asp Ala Asp
90 95 100 105
CCA TGG AAG GCT TTT ATG GCA CAA GTT GAA GTA CTG ATA GAT AAG AAA 506 Pro Trp Lys Ala Phe Met Ala Gln Val Glu Val Leu Ile Asp Lys Lys
110 115 120
ATA GAG GAG TAT GCT AAA AGT AAA GCT CTT GCA GAG TTA CAG GGT CTT 554 He Glu Glu Tyr Ala Lys Ser Lys Ala Leu Ala Glu Leu Gln Gly Leu
125 130 135
CAA AAT AAT TTC GAA GAT TAT GTT AAT GCG TTA AAT TCC TGG AAG AAA 602 Gln Asn Asn Phe Glu Asp Tyr Val Asn Ala Leu Asn Ser Trp Lys Lys
140 145 150
ACA CCT TTA AGT TTG CGA AGT AAA AGA AGC CAA GAT CGA ATA AGG GAA 650 Thr Pro Leu Ser Leu Arg Ser Lys Arg Ser Gln Asp Arg Ile Arg Glu
155 160 165
CTT TTT TCT CAA GCA GAA AGT CAT TTT CGT AAT TCC ATG CCG TCA TTT 698 Leu Phe Ser Gln Ala Glu Ser His Phe Arg Asn Ser Met Pro Ser Phe
170 175 180 185
GCA GTT TCC AAA TTC GAA GTG CTG TTT CTA CCA ACA TAT GCA CAA GCT 746 Ala Val Ser Lys Phe Glu Val Leu Phe Leu Pro Thr Tyr Ala Gln Ala
190 195 200 GCA AAT ACA CAT TTA TTG CTA TTA AAA GAT GCT CAA GTT TTT GGA GAA 794 Ala Asn Thr His Leu Leu Leu Leu Lys Asp Ala Gln Val Phe Gly Glu
205 210 215
GAA TGG GGA TAT TCT TCA GAA GAT GTT GCT GAA TTT TAT CAT AGA CAA 842 Glu Trp Gly Tyr Ser Ser Glu Asp Val Ala Glu Phe Tyr His Arg Gln
220 225 230
TTA AAA CTT ACG CAA CAA TAC ACT GAC CAT TGT GTC AAT TGG TAT AAT 890 Leu Lys Leu Thr Gln Gln Tyr Thr Asp His Cys Val Asn Trp Tyr Asn
235 240 245
GTT GGA TTA AAT GGT TTA AGA GGT TCA ACT TAT GAT GCA TGG GTC AAA 938 Val Gly Leu Asn Gly Leu Arg Gly Ser Thr Tyr Asp Ala Trp Val lys
250 255 260 265
TTT AAC CGT TTT CGC AGA GAA ATG ACT TTA ACT GTA TTA GAT CTA ATT 986 Phe Asn Arg Phe Arg Arg Glu Met Thr Leu Thr Val Leu Asp Leu Ile
270 275 280
GTA CTT TTC CCA TTT TAT GAT GTT CGG TTA TAC TCA AAA GGT GTT AAA 1034
Val Leu Phe Pro Phe Tyr Asp Val Arg Leu Tyr Ser Lys Gly Val Lys
285 290 295
ACA GAA CTA ACA AGA GAC ATT TTT ACG GAT CCA ATT TTT TCA CTC AAT 1082 Thr Glu Leu Thr Arg Asp Ile Phe Thr Asp Pro Ile Phe Ser Leu Asn
300 305 310
ACT CTT CAG GAG TAT GGA CCA ACT TTT TTG AGT ATA GAA AAC TCT ATT 1130 Thr Leu Gln Glu Tyr Gly Pro Thr Phe Leu Ser Ile Glu Asn Ser Ile
315 320 325
CGA AAA CCT CAT TTA TTT GAT TAT TTA CAG GGT ATT GAA TTT CAT ACG 1178 Arg Lys Pro His Leu Phe Asp Tyr Leu Gln Gly Ile Glu Phe His Thr
330 335 340 345
CGT CTT CAA CCT GGT TAC TCT GGG AAA GAT TCT TTC AAT TAT TGG TCT 1226 Arg Leu Gln Pro Gly Tyr Ser Gly Lys Asp Ser Phe Asn Tyr Trp Ser
350 355 360
GGT AAT TAT GTA GAA ACT AGA CCT AGT ATA GGA TCT AGT AAG ACA ATT 1274 Gly Asn Tyr Val Glu Thr Arg Pro Ser Ile Gly Ser Ser Lys Thr Ile
365 370 375
ACT TCC CCA TTT TAT GGA GAT AAA TCT ACT GAA CCT GTA CAA AAG TTA 1322 Thr Ser Pro Phe Tyr Gly Asp Lys Ser Thr Glu Pro Val Gln Lys Leu
380 385 390
AGC TTT GAT GGA CAA AAA GTT TAT CGA ACT ATA GCT AAT ACA GAC GTA 1370 Ser Phe Asp Gly Gln Lys Val Tyr Arg Thr Ile Ala Asn Thr Asp Val
395 400 405
GCG GCT TGG CCG AAT GGC AAG ATA TAT TTT GGT GTT ACG AAA GTT GAT 1418 Ala Ala Trp Pro ASn Gly Lys Ile Tyr Phe Gly Val Thr Lys Val Asp
410 415 420 425
TTT AGT CAA TAT GAT GAT CAA AAA AAT GAA ACT AGT ACA CAA ACA TAT 1466 Phe Ser Gln Tyr Asp Asp Gln Lys Asn Glu Thr Ser Thr Gln Thr Tyr
430 435 440 GAT TCA AAA AGA AAC AAT GGC CAT GTA GGT GCA CAG GAT TCT ATT GAC 1514 Asp Ser Lys Arg Asn Asn Gly His Val Gly Ala Gln Asp Ser Ile Asp
445 450 455
CAA TTA CCA CCA GAA ACA ACA GAT GAA CCA CTT GAA AAA GCA TAT AGT 1562 Gln Leu Pro Pro Glu Thr Thr Asp Glu Pro Leu Glu Lys Ala Tyr Ser
460 465 470
CAT CAG CTT AAT TAC GCG GAA TGT TTC TTA ATG CAG GAC CGT CGT GGA 1610 His Gln Leu Asn Tyr Ala Glu Cys Phe Leu Met Gln Asp Arg Arg Gly
475 480 485
ACA ATT CCA TTT TTT ACT TGG ACA CAT AGA AGT GTA GAC TTT TTT AAT 1658 Thr Ile Pro Phe Phe Thr Trp Thr His Arg Ser Val Asp Phe Phe Asn
490 495 500 505
ACA ATT GAT GCT GAA AAG ATT ACT CAA CTT CCA GTA GTG AAA GCA TAT 1706 Thr Ile Asp Ala Glu Lys Ile Thr Gln Leu Pro Val Val Lys Ala Tyr
510 515 520
GCC TTG TCT TCA GGT GCT TCC ATT ATT GAA GGT CCA GGA TTC ACA GGA 1754
Ala Leu Ser Ser Gly Ala Ser Ile Ile Glu Gly Pro Gly Phe Thr Gly
525 530 535
GGA AAT TTA CTA TTC CTA AAA GAA TCT AGT AAT TCA ATT GCT AAA TTT 1802 Gly Asn Leu Leu Phe Leu Lys Glu Ser Ser Asn Ser Ile Ala Lys Phe
540 545 550
AAA GTT ACA TTA AAT TCA GCA GCC TTG TTA CAA CGA TAT CGT GTA AGA 1850 Lys Val Thr Leu Asn Ser Ala Ala Leu Leu Gln Arg Tyr Arg Val Arg
555 560 565
ATA CGC TAT GCT TCT ACC ACT AAC TTA CGA CTT TTT GTG CAA AAT TCA 1898 Ile Arg Tyr Ala Ser Thr Thr Asn Leu Arg Leu Phe Val Gln Asn Ser
570 575 580 585
AAC AAT GAT TTT ATT GTC ATC TAC ATT AAT AAA ACT ATG AAT ATA GAT 1946 Asn Asn Asp Phe Ile Val Ile Tyr Ile Asn Lys Thr Met Asn Ile Asp
590 595 600
GAT GAT TTA ACA TAT CAA ACA TTT GAT CTC GCA ACT ACT AAT TCT AAT 1994 Asp Asp Leu Thr Tyr Gln Thr Phe Asp Leu Ala Thr Thr Asn Ser Asn
605 610 615
ATG GGG TTC TCG GGT GAT ACG AAT GAA CTT ATA ATA GGA GCA GAA TCT 2042 Met Gly Phe Ser Gly Asp Thr Asn Glu Leu Ile Ile Gly Ala Glu Ser
620 625 630
TTC GTT TCT AAT GAA AAA ATC TAT ATA GAT AAG ATA GAA TTT ATC CCA 2090 Phe Val Ser Asn Glu Lys Ile Tyr Ile Asp Lys Ile Glu Phe Ile Pro
635 640 645
GTA CAA TTG TAAGGAGATT TTGAAATGTA GGGCGATGGT CAAAATGAAA 2139
Val Gln Leu
650
GAATAGGAAG GTGAATTTTG ATGGTTAGGA AAGATTCTTT TAAGAAAAGC AACATGGAAA 2199
AGTATACAGT ACAAATATTA GAAATAAAAT TTATTAACAC AGGGGAAGAT GGTAAACCAG 2259 AACCGTATGG TTATATTGAC TTTTATTATC AACCTGCTCC TAACCTGAGA GAAGAAAAAG 2319 TAAGAATTTG GGAAGAGAAA AATAGTAGCT CTCCACCTTC AATAGAAGTT ATTACGGGGC 2379 TAACTTTTAA TATCATGGCT ACTTCACTTA GCCGATTATG TTTTGAAGGT T 2430
(2) INFORMATION FOR SEQ ID NO: 2:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 652 amino acids
(B) TYPE: amino acid
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: protein
(Xi) SEQUENCE DESCRIPTION: SEQ ID NO: 2:
Met Asn Pro Asn Asn Arg Ser Glu His Asp Thr Ile Lys Val Thr Pro
1 5 10 15
Asn Ser Glu Leu Pro Thr Asn His Asn Gln Tyr Pro Leu Ala Asp Asn
20 25 30
Pro Asn Ser Thr Leu Glu Glu Leu Asn Tyr Lys Glu Phe Leu Arg Met
35 40 45
Thr Glu Asp Ser Ser Thr Glu Val Leu Asp Asn Ser Thr Val Lys Asp
50 55 60
Ala Val Gly Thr Gly Ile Ser Val Val Gly Gln Ile Leu Gly Val Val
65 70 75 80
Gly Val Pro Phe Ala Gly Ala Leu Thr Ser Phe Tyr Gln Ser Phe Leu
85 90 95
Asp Thr Ile Trp Pro Ser Asp Ala Asp Pro Trp Lys Ala Phe Met Ala
100 105 110
Gln Val Glu Val Leu Ile Asp Lys Lys Ile Glu Glu Tyr Ala Lys Ser
115 120 125
Lys Ala Leu Ala Glu Leu Gln Gly Leu Gln Asn Asn Phe Glu Asp Tyr
130 135 140
Val Asn Ala Leu Asn Ser Trp Lys Lys Thr Pro Leu Ser Leu Arg Ser
145 150 155 160
Lys Arg Ser Gln Asp Arg Ile Arg Glu Leu Phe Ser Gln Ala Glu Ser
165 170 175
His Phe Arg Asn Ser Met Pro Ser Phe Ala Val Ser Lys Phe Glu Val
180 185 190
Leu Phe Leu Pro Thr Tyr Ala Gln Ala Ala Asn Thr His Leu Leu Leu
195 200 205
Leu Lys Asp Ala Gln Val Phe Gly Glu Glu Trp Gly Tyr Ser Ser Glu
210 215 220 Asp Val Ala Glu Phe Tyr His Arg Gln Leu Lys Leu Thr Gln Gln Tyr 225 230 235 240
Thr Asp His Cys Val Asn Trp Tyr Asn Val Gly Leu Asn Gly Leu Arg
245 250 255
Gly Ser Thr Tyr Asp Ala Trp Val Lys Phe Asn Arg Phe Arg Arg Glu
260 265 270
Met Thr Leu Thr Val Leu Asp Leu Ile Val Leu Phe Pro Phe Tyr Asp
275 280 285
Val Arg Leu Tyr Ser Lys Gly Val Lys Thr Glu Leu Thr Arg Asp lie 290 295 300
Phe Thr Asp Pro Ile Phe Ser Leu Asn Thr Leu Gln Glu Tyr Gly Pro 305 310 315 320
Thr Phe Leu Ser Ile Glu Asn Ser Ile Arg Lys Pro His Leu Phe Asp
325 330 335
Tyr Leu Gln Gly Ile Glu Phe His Thr Arg Leu Gln Pro Gly Tyr Ser
340 345 350
Gly Lys Asp Ser Phe Asn Tyr Trp Ser Gly Asn Tyr Val Glu Thr Arg
355 360 365
Pro Ser Ile Gly Ser Ser Lys Thr Ile Thr Ser Pro Phe Tyr Gly Asp 370 375 380
Lys Ser Thr Glu Pro Val Gln Lys Leu Ser Phe Asp Gly Gln Lys Val 385 390 395 400
Tyr Arg Thr Ile Ala Asn Thr Asp Val Ala Ala Trp Pro Asn Gly Lys
405 410 415 Ile Tyr Phe Gly Val Thr Lys Val Asp Phe Ser Gln Tyr Asp Asp Gln
420 425 430
Lys Asn Glu Thr Ser Thr Gln Thr Tyr Asp Ser Lys Arg Asn Asn Gly
435 440 445
His Val Gly Ala Gln Asp Ser Ile Asp Gln Leu Pro Pro Glu Thr Thr 450 455 460
Asp Glu Pro Leu Glu Lys Ala Tyr Ser His Gln Leu Asn Tyr Ala Glu 465 470 475 480
Cys Phe Leu Met Gln Asp Arg Arg Gly Thr Ile Pro Phe Phe Thr Trp
485 490 495
Thr His Arg Ser Val Asp Phe Phe Asn Thr Ile Asp Ala Glu Lys Ile
500 505 510
Thr Gln Leu Pro Val Val Lys Ala Tyr Ala Leu Ser Ser Gly Ala Ser
515 520 525
Ile Ile Glu Gly Pro Gly Phe Thr Gly Gly Asn Leu Leu Phe Leu Lys 530 535 540 Glu Ser Ser Asn Ser Ile Ala Lys Phe Lys Val Thr Leu Asn Ser Ala 545 550 555 560
Ala Leu Leu Gln Arg Tyr Arg Val Arg Ile Arg Tyr Ala Ser Thr Thr
565 570 575
Asn Leu Arg Leu Phe Val Gln Asn Ser Asn Asn Asp Phe Ile Val Ile
580 585 590
Tyr Ile Asn Lys Thr Met Asn Ile Asp Asp Asp Leu Thr Tyr Gln Thr
595 600 605
Phe Asp Leu Ala Thr Thr Asn Ser Asn Met Gly Phe Ser Gly Asp Thr 610 615 620
Asn Glu Leu Ile Ile Gly Ala Glu Ser Phe Val Ser Asn Glu Lys Ile 625 630 635 640
Tyr Ile Asp Lys Ile Glu Phe Ile Pro Val Gln Leu
645 650
Figure imgf000075_0001
ATTACHMENT TO FORM PCT/RO/134
CONTINUATION OF "MICROORGANISM" BOX:
page 10, lines 3-11
page 26, lines 21-22
page 28, lines 10-12
page 42, lines 22-24
page 47, lines 26-27
CONTINUATION OF IDENTIFICATION OF DEPOSIT BOX A:
The following microorganisms were deposited in the depository institution listed in Box A on the dates listed below:
Bacterial Strain NRRL Acession No. Date of Deposit
B. thuringiensis EG2158 B-18213 29 April 1987
B. thuringiensis HD73-26 B-18508 12 June 1989
B. thuringiensis EG2838 B-18603 8 February 1990 B. thuringiensis EG5144 B-18655 22 May 1990
B. thuringiensis EG7237 B-18736 17 October 1990 B. thuringiensis EG5145 B-18920 21 November 1991 E. coli EG7236 B-18662 6 June 1990

Claims

CLAIMS WE CLAIM:
1. A purified and isolated cryΙIIC(b) gene
characterized in that its nucleotide base sequence encodes the amino acid sequence illustrated in Figure 1 (SEQ ID NO:2).
2. A purified and isolated cryΙIIC (b) gene according to claim 1 further characterized in that the gene has a coding region extending from nucleotide bases 144 to 2099 in the nucleotide base sequence illustrated in Figure 1 (SEQ ID NO:1).
3. A recombinant plasmid containing the gene of claim 1 or claim 2.
4. A coleopteran-toxic protein produced by the gene of claim 1 or claim 2.
5. A biologically pure culture of a bacterium
transformed with the recombinant plasmid of claim 3.
6. The bacterium of claim 5 further characterized in that the bacterium is Bacillus thuringiensis .
7. The Bacillus thuringiensis bacterium of claim 6 deposited with the NRRL with accession number NRRL B- 18736.
8. An insecticide composition characterized in that the composition comprises the protein of claim 4 and an agriculturally acceptable carrier.
9. An insecticide composition characterized in that the composition comprises the bacterium of claim 5, a coleopteran-toxic protein produced by such bacterium, and an agriculturally acceptable carrier.
10. A plant characterized in that the plant is transformed with the gene of claim 1 or claim 2.
11. The cryΙIIC(b) gene of claim 2 further
characterized in that the gene or a portion thereof is labelled for use as a hybridization probe.
12. A biologically pure culture of a Bacillus
thuringiensis bacterium deposited with the NRRL with accession number NRRL B-18655.
13. A coleopteran-toxic protein characteristic of that made by the Bacillus thuringiensis bacterium of claim 12 and having the amino acid sequence illustrated in Figure 1 (SEQ ID NO: 2).
14. An insecticide composition characterized in that the composition comprises the coleopteran-toxic protein of claim 13, in combination with an agriculturally acceptable carrier.
15. The insecticide composition of claim 14 further characterized in that the coleopteran-toxic protein is associated with a Bacillus thuringiensis bacterium which has produced such protein.
16. A method of controlling coleopteran insects characterized by applying to a host plant for such insects an insecticidally effective amount of the coleopteran-toxic protein of claim 4.
17. The method of claim 16 further characterized in that the coleopteran-toxic protein is associated with a Bacillus thuringiensis bacterium which has. produced such protein.
18. The method according to claim 16 further
characterized in that the insects are selected from the group consisting of corn rootworms, Mexican bean beetles and Japanese beetle larvae.
19. A method of controlling coleopteran insects characterized by applying to a host plant for such insects an insecticidally effective amount of the coleopteran-toxic protein of claim 13.
20. The method of claim 19 further characterized in that the coleopteran-toxic protein is associated with a Bacillus thuringiensis bacterium which has produced such protein.
21. The method of claim 19 further characterized in that the insects are selected from the group consisting of corn rootworms, Mexican bean beetles and Japanese beetle larvae.
22. A biologically pure culture of a Bacillus
thuringiensis bacterium deposited with the NRRL with accession number NRRL B-18920.
23. An insecticide composition characterized in that the composition comprises the coleopteran-toxic protein obtainable from the Bacillus thuringiensis bacterium of claim 12 or claim 22, in combination with an
agriculturally acceptable carrier.
PCT/US1992/000040 1991-01-31 1992-01-03 BACILLUS THURINGIENSIS CRYIIIC(b) TOXIN GENE AND PROTEIN TOXIC TO COLEOPTERAN INSECTS WO1992013954A1 (en)

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JP4503832A JP2531913B2 (en) 1991-01-31 1992-01-03 Bacillus thuringiensis cryIIIC (b) toxin gene and protein toxic to beetle insects
AU11926/92A AU649785B2 (en) 1991-01-31 1992-01-03 Bacillus thuringiensis cryIIIC(b) toxin gene and protein toxic to coleopteran insects

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5369027A (en) * 1993-07-12 1994-11-29 Plant Genetic Systems, N.V. Bacillus thuringiensis strains toxic to diabrotica species
WO1994028724A1 (en) * 1993-06-10 1994-12-22 Ecogen Inc. Bacillus thuringiensis strains capable of producing large amonts of insecticidal crystal proteins
US5382429A (en) * 1990-03-20 1995-01-17 Ecogen Inc. Bacillus thuringiensis protein toxic to coleopteran insects
WO1999031248A1 (en) * 1997-12-18 1999-06-24 Ecogen, Inc. INSECT-RESISTANT TRANSGENIC PLANTS AND METHODS FOR IMPROVING δ-ENDOTOXIN ACTIVITY AGAINST TARGET INSECTS
US6063756A (en) * 1996-09-24 2000-05-16 Monsanto Company Bacillus thuringiensis cryET33 and cryET34 compositions and uses therefor
US7227056B2 (en) 1997-12-18 2007-06-05 Monsanto Technology Llc Coleopteran-resistant transgenic plants and methods of their production
US8101826B2 (en) 1999-08-19 2012-01-24 Monsanto Technology Llc Expression of Cry3B insecticidal protein in plants
WO2018185048A1 (en) * 2017-04-03 2018-10-11 Novozymes A/S Recovery process
CN110029114A (en) * 2019-04-12 2019-07-19 河南农业大学 Heat-resisting gene C RY1 and its preparation method and application of application, saccharomycete and saccharomycete

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1988008880A1 (en) * 1987-05-06 1988-11-17 Ecogen, Incorporated Coleopteran active microorganisms, related insecticide compositions and methods for their production and use
EP0328383A1 (en) * 1988-02-12 1989-08-16 Mycogen Corporation Novel coleopteran-active bacillus thuringiensis isolate
EP0382990A1 (en) * 1989-02-15 1990-08-22 Plant Genetic Systems, N.V. Strains of bacillus thuringiensis
WO1991014778A2 (en) * 1990-03-20 1991-10-03 Ecogen Inc. BACILLUS THURINGIENSIS cryIIIC GENE AND PROTEIN TOXIC TO COLEOPTERAN INSECTS
WO1991016433A1 (en) * 1990-04-26 1991-10-31 Plant Genetic Systems N.V. New bacillus thuringiensis strains and their genes encoding insecticidal toxins

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02504682A (en) * 1987-08-21 1990-12-27 コモンウエルス・サイエンティフィック・アンド・インダストリアル・リサーチ・オーガニゼイション Conversion processing circuit

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1988008880A1 (en) * 1987-05-06 1988-11-17 Ecogen, Incorporated Coleopteran active microorganisms, related insecticide compositions and methods for their production and use
EP0328383A1 (en) * 1988-02-12 1989-08-16 Mycogen Corporation Novel coleopteran-active bacillus thuringiensis isolate
EP0382990A1 (en) * 1989-02-15 1990-08-22 Plant Genetic Systems, N.V. Strains of bacillus thuringiensis
WO1991014778A2 (en) * 1990-03-20 1991-10-03 Ecogen Inc. BACILLUS THURINGIENSIS cryIIIC GENE AND PROTEIN TOXIC TO COLEOPTERAN INSECTS
WO1991016433A1 (en) * 1990-04-26 1991-10-31 Plant Genetic Systems N.V. New bacillus thuringiensis strains and their genes encoding insecticidal toxins

Cited By (21)

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US5382429A (en) * 1990-03-20 1995-01-17 Ecogen Inc. Bacillus thuringiensis protein toxic to coleopteran insects
WO1994028724A1 (en) * 1993-06-10 1994-12-22 Ecogen Inc. Bacillus thuringiensis strains capable of producing large amonts of insecticidal crystal proteins
US5369027A (en) * 1993-07-12 1994-11-29 Plant Genetic Systems, N.V. Bacillus thuringiensis strains toxic to diabrotica species
US5422106A (en) * 1993-07-12 1995-06-06 Plant Genetic Systems, N.V. Method of controlling coleotera using Bacillus thuringiensis strains MG P-14025 and LMG P-14026
US7504229B2 (en) 1996-09-24 2009-03-17 Monsanto Technology Llc Methods for detecting Bacillus thuringiensis cryET33 and cryET34 polypeptides
US6063756A (en) * 1996-09-24 2000-05-16 Monsanto Company Bacillus thuringiensis cryET33 and cryET34 compositions and uses therefor
US6248536B1 (en) 1996-09-24 2001-06-19 Monsanto Company Bacillus thuringiensis CryET33 and CryET34 compositions and uses thereof
US6399330B1 (en) 1996-09-24 2002-06-04 Monsanto Technology Llc Bacillus thuringiensis cryet33 and cryet34 compositions and uses thereof
US6949626B2 (en) 1996-09-24 2005-09-27 Monsanto Technology Llc Bacillus thuringiensis cryET33 and cryET34 compositions and uses therefor
US7385107B2 (en) 1996-09-24 2008-06-10 Monsanto Technologies Llc Insect-resistant transgenic plants transformed with CryET33 and CryET34-encoding nucleic acids
US7227056B2 (en) 1997-12-18 2007-06-05 Monsanto Technology Llc Coleopteran-resistant transgenic plants and methods of their production
EP1801220A3 (en) * 1997-12-18 2007-08-22 Monsanto Technology, LLC Insect-resistant transgenic plants and methods for improving delta-endotoxin activity against insects
CN100340666C (en) * 1997-12-18 2007-10-03 孟山都技术有限公司 Insect-risistant transgenic plants and methods for improving 'delta' -endotoxin activity against target insects
EP1749834A1 (en) * 1997-12-18 2007-02-07 Monsanto Technology LLC Insect-resistant transgenic plants and methods for improving delta-endotoxin activity against target insects
WO1999031248A1 (en) * 1997-12-18 1999-06-24 Ecogen, Inc. INSECT-RESISTANT TRANSGENIC PLANTS AND METHODS FOR IMPROVING δ-ENDOTOXIN ACTIVITY AGAINST TARGET INSECTS
US7544862B2 (en) 1997-12-18 2009-06-09 Monsanto Technology Llc Coleopteran-resistant transgenic plants and methods of their production
US8513492B2 (en) 1997-12-18 2013-08-20 Monsanto Technology Llc Coleopteran-resistant transgenic plants and methods of their production
US8101826B2 (en) 1999-08-19 2012-01-24 Monsanto Technology Llc Expression of Cry3B insecticidal protein in plants
WO2018185048A1 (en) * 2017-04-03 2018-10-11 Novozymes A/S Recovery process
CN110029114A (en) * 2019-04-12 2019-07-19 河南农业大学 Heat-resisting gene C RY1 and its preparation method and application of application, saccharomycete and saccharomycete
CN110029114B (en) * 2019-04-12 2022-11-04 河南农业大学 Heat-resistant gene CRY1 and application thereof, yeast and preparation method and application of yeast

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AU649785B2 (en) 1994-06-02
JPH06502077A (en) 1994-03-10

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