WO1999066056A1 - Procede d'obtention de polysaccharides modifies - Google Patents
Procede d'obtention de polysaccharides modifies Download PDFInfo
- Publication number
- WO1999066056A1 WO1999066056A1 PCT/FR1999/001446 FR9901446W WO9966056A1 WO 1999066056 A1 WO1999066056 A1 WO 1999066056A1 FR 9901446 W FR9901446 W FR 9901446W WO 9966056 A1 WO9966056 A1 WO 9966056A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- starch
- enzyme
- glucanotransferase
- glycogen
- plants
- Prior art date
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
- C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
- C12N9/00—Enzymes; Proenzymes; Compositions thereof; Processes for preparing, activating, inhibiting, separating or purifying enzymes
- C12N9/10—Transferases (2.)
- C12N9/1048—Glycosyltransferases (2.4)
- C12N9/1051—Hexosyltransferases (2.4.1)
-
- C—CHEMISTRY; METALLURGY
- C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
- C12N—MICROORGANISMS OR ENZYMES; COMPOSITIONS THEREOF; PROPAGATING, PRESERVING, OR MAINTAINING MICROORGANISMS; MUTATION OR GENETIC ENGINEERING; CULTURE MEDIA
- C12N15/00—Mutation or genetic engineering; DNA or RNA concerning genetic engineering, vectors, e.g. plasmids, or their isolation, preparation or purification; Use of hosts therefor
- C12N15/09—Recombinant DNA-technology
- C12N15/63—Introduction of foreign genetic material using vectors; Vectors; Use of hosts therefor; Regulation of expression
- C12N15/79—Vectors or expression systems specially adapted for eukaryotic hosts
- C12N15/82—Vectors or expression systems specially adapted for eukaryotic hosts for plant cells, e.g. plant artificial chromosomes (PACs)
- C12N15/8241—Phenotypically and genetically modified plants via recombinant DNA technology
- C12N15/8242—Phenotypically and genetically modified plants via recombinant DNA technology with non-agronomic quality (output) traits, e.g. for industrial processing; Value added, non-agronomic traits
- C12N15/8243—Phenotypically and genetically modified plants via recombinant DNA technology with non-agronomic quality (output) traits, e.g. for industrial processing; Value added, non-agronomic traits involving biosynthetic or metabolic pathways, i.e. metabolic engineering, e.g. nicotine, caffeine
- C12N15/8245—Phenotypically and genetically modified plants via recombinant DNA technology with non-agronomic quality (output) traits, e.g. for industrial processing; Value added, non-agronomic traits involving biosynthetic or metabolic pathways, i.e. metabolic engineering, e.g. nicotine, caffeine involving modified carbohydrate or sugar alcohol metabolism, e.g. starch biosynthesis
Definitions
- the present invention relates to a process for obtaining plants producing modified polysaccharides (such as starch or glycogen), these modified polysaccharides extracted from these plants and the products prepared from these modified polysaccharides.
- modified polysaccharides such as starch or glycogen
- Starch is the energy storage polysaccharide in plants. It constitutes the main caloric intake of animal and human food and is also a major source of vegetable raw material for non-food uses. Starch is composed of two distinct polysaccharide fractions: amylose and amylopectin. Amylose, which represents the minority fraction of starch, consists of glucose residues united by ⁇ -1, 4 bonds, and has less than 1% of branches. Amylopectin, which represents the majority fraction of starch, consists of glucose residues united by ⁇ -1, 4 bonds, and has about 5% of branches, formed by glucose residues linked to the main polymer by a bond ⁇ -1, 6. The asymmetric distribution of the branching of amylopectin is responsible for the unlimited growth of molecules and consequently of starch grains, and also accounts for most of the physicochemical properties of starch.
- the biosynthesis of starch depends on a pathway, the main biochemical steps of which are the synthesis of ADP-glucose followed by the transfer of this precursor in position ⁇ -1, 4 onto a glucan by (ADP-glucose: 1, 4- ⁇ - D-glucan 4- ⁇ -D-glucosyl) transferases, the polymer formed being branched by the action of enzymes called branching or "branching": the 1,4- ⁇ -D-glucan 6- ⁇ -D- (1, 4- ⁇ -D-glucano) -transferases.
- Figure 1 attached is a simplified diagram of the metabolism of starch hitherto known to those skilled in the art.
- the known plant ⁇ -1, 4 glucanotransferases (or 4- ⁇ -D-glucanotransferases) are commonly referred to as “enzymes D” for “disproportionating enzymes". They catalyze the transfer of glucan from one 1,4- ⁇ -glucan molecule to another (intermolecular transglycosylation).
- Enzymes D catalyze the transfer of glucan from one 1,4- ⁇ -glucan molecule to another (intermolecular transglycosylation).
- the rules of action of the enzyme D on oligosaccharide substrates are schematized as follows:
- Maltose cannot serve as a donor substrate and only a bond at the end of the maltotriose can be attacked.
- the first bond on the non-reducing side and the penultimate bond on the reducing side are resistant to the action of the enzyme.
- the enzyme D does not have a direct role on the structures and the quantities of starch produced but plays a role in the growth of the plant and its development, amylopectin and amylose serving as donor molecules for the transfer of maltooligosaccharide to glucose, thus allowing the dislocation and the solubilization of the starch grains (Takada et al, 1998).
- the authors of the present invention have discovered that the ⁇ -1, 4 glucanotransferases, and in particular the enzymes D are in fact involved in the biosynthesis of starch, by transferring oligosaccharides on a precursor of amylopectin.
- These enzymes can in particular transfer the oligosaccharides from the pool of oligosaccharides produced in vivo by debranching of the precursor of amylopectin during the maturation of amylopectin. They can in particular transfer the oligosaccharides which may contain, for example from 2 to 20, in particular from 2 to 6, glucose residues.
- Figure 2 attached shows the role of the enzyme D in the cycle of starch metabolism, as discovered by the authors of the present invention.
- This discovery was used to modify, as a function of the level of enzyme ⁇ -1,4 active glucanotransferase present, the distribution of the lengths of the chains of amylopectin, present in particular in the reserve organs of plants.
- the invention also applies to glycogen, present in a smaller amount than amylopectin in plants but which can be found, for example, in sweet corn kernels, allowing in the same way the modification of the distribution of the length of the glycogen chains.
- the present invention therefore relates to the use of a nucleic acid coding for an enzyme ⁇ -1,4 glucanotransferase glucanotransferase or an antisense sequence of said sequence coding for an enzyme ⁇ -1,4 glucanotransferase, to modify the distribution of the length of the external chains of starch (i.e. amylopectin and / or amylose) or glycogen.
- a nucleic acid coding for an enzyme ⁇ -1,4 glucanotransferase glucanotransferase or an antisense sequence of said sequence coding for an enzyme ⁇ -1,4 glucanotransferase to modify the distribution of the length of the external chains of starch (i.e. amylopectin and / or amylose) or glycogen.
- the present invention relates more particularly to a process for modifying the distribution of the length of the chains of amylopectin in a starch or of the chains of a glycogen in which the activity of an enzyme ⁇ is increased or decreased -1,4 glucanotransferase in the cells of a plant so that said plant produces a modified starch different from the starch produced naturally by plants by distribution of the length of the chains of amylopectin or produce a modified glycogen different from the glycogen produced naturally by the distribution of the length of its external chains.
- the level of expression of enzyme ⁇ -1, 4 endogenous glucanotransferase is reduced, so as to lead to the production of a starch comprising an amylopectin having an enrichment in chains comprising less of 6 glucose residues compared to a naturally produced starch.
- the reduction of the expression of an endogenous ⁇ -1,4 glucanotransferase enzyme can be carried out in particular according to the method comprising the steps consisting in: a) constructing an expression vector comprising an antisense nucleotide sequence of the gene coding for said enzyme ⁇ -1, 4 endogenous glucanotransferase; b) transforming a plant cell with said expression vector; c) regenerating the plant from the cell transformed in step b, said transgenic plant thus obtained producing a starch comprising an amylopectin whose distribution of chain lengths is altered, in particular in the sense of an enrichment in chains comprising less of 6 glucose residues.
- said plant cell transformed according to step b) is also transformed by antisense nucleotide sequences of the genes coding for enzymes affecting the length distribution of the oligosaccharides produced during the metabolism of starch, such as phosphorylases. and amylases.
- ribozymes which are RNA molecules which act as enzymes which specifically catalyze the cleavage of transcripts encoding l the enzyme the ⁇ -1,4 glucanotransferase enzyme, by techniques known to those skilled in the art (EP 321,021). It is also possible to obtain a plant exhibiting an alteration in the expression of the enzyme ⁇ -1,4 glucanotransferase by the process known as "transwitch" described in WO90 / 12084.
- the activity of the enzyme endogenous ⁇ -1,4 glucanotransferase can also be reduced by mutagenesis of plant cells either by U.V irradiation or by a chemical mutagenic agent, or by insertion of transposons.
- Transposable elements have the ability to disrupt the expression of genes into which they are inserted and to generate deletions, rearrangements, and mutations at the target locus (McClintock et al., 1950).
- mutagenesis by transposon Mutator confirmed by a screening in reverse genetics (Bensen et a I., 1995) (Das et al., 1995). This technique implements the steps consisting in crossing a “Mutator” line with hybrids of the plants of interest then in screening the F1 plants obtained by PCR with a primer specific for transposons and a primer specific for the nucleotide sequence coding for enzyme ⁇ -1, 4 glucanotransferase. The seeds F2 obtained from the plants screened F1 make it possible to obtain plants whose phenotype is then analyzed.
- the level of expression of enzyme ⁇ -1,4 glucanotransferase in the plant is increased, so as to lead to the production of a starch comprising an amylopectin having an enrichment in chains. comprising at least 9 glucose residues relative to a naturally produced starch, said enzyme ⁇ -1, 4 glucanotransferase being identical to the enzyme ⁇ -1, 4 glucanotransferase endogenous or being of heterologous origin.
- the increase in the level of enzyme ⁇ -1, 4 glucanotransferase can in particular be carried out according to the method comprising the steps consisting in: a) constructing an expression vector comprising a nucleotide sequence coding for an enzyme ⁇ -1, 4 glucanotransferase, who may be an enzyme ⁇ -1,4 glucanotransferase identical to the enzyme ⁇ -1,4 glucanotransferase endogenous or which may be of heterologous origin; b) transforming a plant cell with said expression vector; c) regenerating the plant from the cell transformed in step b), said transgenic plant thus obtained producing a starch comprising an amylopectin whose distribution of chain lengths is altered, in particular in the sense of an enrichment in chains comprising at least 9 glucose residues.
- said plant cell transformed according to step b) is also transformed by nucleotide sequences coding for enzymes affecting the length distribution of the oligosaccharides produced during the metabolism of starch, such as phosphorylases and amylases .
- the enzyme ⁇ -1,4 glucanotransferase targeted is an enzyme D.
- Said nucleotide sequence coding for an enzyme ⁇ -1,4 glucanotransferase may be of heterologous origin. It can thus correspond in particular to an enzyme chosen from the enzyme D of the potato (Takaha et al, 1993) or the enzyme D of Chlamydomonas reinhardtii.
- nucleic acid comprising a nucleotide sequence chosen from the sequence SEQ ID No. 1, a homologous sequence and a fragment of this sequence coding for a protein having an enzymatic activity of ⁇ -1,4 glucanotransferase.
- the invention also comprises the sequences complementary to the sequence SEQ ID No. 1 or of its homologs and fragment, which can serve as antisense sequences in the method of the invention.
- sequence SEQ ID No. 1 represents a genomic DNA fragment of the gene coding for the enzyme D of Chlamydomonas reinhardtii.
- homologous nucleotide sequence is meant any nucleotide sequence which differs from the sequence SEQ ID No. 1 by substitution, deletion, and / or insertion of a nucleotide or of a reduced number of nucleotides, at positions such as these nucleotide sequences homologs code for homologous polypeptides as defined below.
- such a homologous nucleotide sequence is identical to at least 75% of the sequence SEQ ID No. 1, preferably at least 85%, more preferably at least 95%.
- such a homologous nucleotide sequence specifically hybridizes to the sequence complementary to the sequence SEQ ID No. 1, under stringent conditions.
- the parameters defining the stringency conditions depend on the temperature at which 50% of the paired strands separate (Tm).
- Tm 81.5 + 0.41 (% G + C) +16.6Log (cation concentration) -
- Tm 4 (G + C) + 2 (A + T).
- the hybridization temperature is approximately 5 to 30 ° C, preferably 5 to 10 ° C below Tm, and the hybridization buffers used are preferably solutions of high ionic strength such as a 6xSSC solution for example.
- nucleotide fragment is meant any fragment of the sequence SEQ ID No. 1, or nucleotide sequences homologous to the sequence SEQID No. 1, which codes for a peptide or a protein having an enzymatic activity of ⁇ -1, 4 glucanotransferase, as defined above.
- the present invention also relates to a cloning and / or expression vector comprising a nucleotide sequence as defined above.
- an expression vector mentioned above is within the reach of those skilled in the art according to standard techniques.
- said expression vector can contain an antisense nucleotide sequence of the gene coding for the said endogenous ⁇ -1,4 glucanotransferase enzyme, according to the first embodiment of the invention, or a nucleotide sequence coding for an ⁇ -1,4 glucanotransferase enzyme, according to the second embodiment of the invention.
- the nucleotide sequence coding for an enzyme ⁇ -1, 4 glucanotransferase is associated with the elements allowing its expression in the plant, namely in particular a promoter and a transcription terminator.
- the transformation of plant cells can be carried out by transfer of the abovementioned vectors into the protoplasts, in particular after incubation of the latter in a polyethylene glycol solution in the presence of divalent cations (Ca 2+ ).
- the transformation of plant cells can also be carried out by electroporation, in particular according to the method described in the article by Fromm et al., 1986.
- the transformation of plant cells can also be carried out by using a gene gun allowing the projection, at very high speed, of metallic particles covered with the DNA sequences of interest, thus delivering genes inside the cell nucleus , in particular according to the technique described in the article by Sanford, (1988).
- Another method of transforming plant cells is that of cytoplasmic or nuclear micro-injection.
- the plant cells are transformed by biolistics, that is to say by projection, by means of a particle gun, of microparticles covered with the nucleotide sequences to be transferred ( J. Finner, 1992).
- the plant cells are transformed by a vector according to the invention, said cellular host being capable of infecting said plant cells by allowing the integration into the genome of the latter, DNA sequences of interest originally contained in the genome of the above vector.
- the above-mentioned cell host used is Agrobacterium tumefaciens, in particular according to the method described in the article. d'An et al., 1986, or Agrobacterium rhizogenes, in particular according to the method described in the article by Jouanin et al., 1987.
- the transformation of plant cells is carried out by the transfer of the T region of the extra chromosomal circular piasmide inducing Ti tumors of Agrobacterium tumefaciens, using a binary system (Watson et al.).
- T-DNA region was deleted, with the exception of the right and left edges, a marker gene being inserted between them to allow selection in plant cells.
- the other partner of the binary system is an auxiliary Ti piasmide, a modified piasmide which no longer has T-DNA but still contains the vir virulence genes, necessary for the transformation of the plant cell. This piasmid is maintained in Agrobacterium.
- transcription terminators which can be used, mention may be made of the polyA 35S terminator of the cauliflower mosaic virus
- NOS which corresponds to the 3 'non-coding region of the nopaline synthase gene from the piasmid Ti to' Agrobacterium tumefaciens nopaline strain
- transcription promoters which can be used, there may be mentioned in particular:
- 35S promoter or advantageously the constitutive double 35S promoter (pd35S) of CaMV, described in the article by Kay et al., 1987;
- the chimeric PSP super-promoter (Ni M et al., 1995), consisting of the fusion of a triple repetition of a transcriptional activator element of the promoter of the octopine synthase gene from Agrobacterium tumefaciens, a transcriptional activating element of the promoter of the mannopine synthase gene and of the mannopine synthase promoter of Agrobacterium tumefaciens;
- the present invention also relates to a plant or part of a plant such as in particular potato, wheat, corn or rice, producing a modified starch different from the starch produced naturally by plants by the distribution of the lengths of its external chains or producing modified glycogen different from the glycogen produced naturally by the distribution of the length of its external chains, said plant or part of plant being obtained by the method of the invention as described above.
- plant part in particular the reserve organs naturally rich in starch, such as seeds or tubers, or the organs naturally rich in glycogen, for example cornflour grains.
- plant part is also meant the cells of said plant.
- the invention also relates to a process for obtaining modified starch or modified glycogen in which a starch or a glycogen is brought into contact with an enzyme ⁇ -1,4 glucanotransferase.
- a more particular subject of the present invention is a process for obtaining modified starch which differs from the starch produced. naturally by plants by the distribution of the lengths of its external chains, in which: the modified starch is extracted from the plants or parts of plants obtained according to the method of the invention, as described above. or a starch, previously extracted from plants or parts of plants and then solubilized, is brought into contact with an enzyme ⁇ -1, 4 glucanotransferase, in the presence of optionally modified polysaccharides or oligosaccharides.
- the extraction of this starch is carried out according to standard techniques known to those skilled in the art.
- starch The solubilization of starch is also known to those skilled in the art and can be carried out by soaking and fractionating the starch grain (Whistler et al, (1967)), or for example by heating.
- enzymes destructuring starch can be used, such as amylases.
- said solubilized starch is brought into contact with an enzyme ⁇ -1,4 glucanotransferase, such as an enzyme D, in the presence of saccharides.
- Said saccharides can in particular be chemically modified oligosaccharides, so as to modify the properties of starch, for example its digestibility.
- ⁇ -1,4 glucanotransferase enzymes affecting the length distribution of the oligosaccharides produced during the metabolism of starch such as phosphorylases and amylases.
- the present invention also relates to a process for obtaining modified glycogen different from the glycogen produced naturally (by plants or by an animal organism) by the distribution of the lengths of its external chains, in which: - the modified glycogen is extracted with starting from the plants or parts of plants obtained according to the method of the invention, as described above. or a glycogen (of plant or animal origin) is brought into contact with an ⁇ -1, 4 glucanotransferase enzyme, in the presence of optionally modified polysaccharides or oligosaccharides.
- Said enzyme ⁇ -1,4 glucanotransferase such as an enzyme D, brought into contact with starch or glycogen, can come from the same species of plant as that from which the starch is extracted or can have a heterologous origin.
- the enzyme D used is thermostable.
- the enzyme D of Chlamydomonas reinhardtii is purified by the process comprising the steps consisting in: - centrifuging the strain Chlamydomonas reinhardtii;
- the purified Chlamydomonas reinhardtii enzyme D thus obtained has a molecular weight of 62kD. More generally, it is possible to use, as protein exhibiting an ⁇ -1, 4 glucanotransferase enzymatic activity, a protein or a peptide encoded by a nucleic acid comprising a nucleotide sequence chosen from the sequence SEQ ID No. 1, a homologous sequence or a fragment of this sequence.
- the present invention also relates to modified starch which differs from the starch produced naturally by plants by the distribution lengths of its chains, said modified starch being obtained by the process of the invention.
- the modified starch obtained by extraction and solubilization of starch from plants or parts of plants, then contacting said solubilized starch with an enzyme ⁇ -1,4 glucanotransferase, optionally in the presence of saccharides, comprises an amylopectin, the distribution of the lengths of the external chains is modified compared to a naturally produced starch.
- the present invention also relates to the modified glycogen which differs from the glycogen produced naturally (for example by plants, but also from the glycogen of animal origin), by the distribution of the lengths of its chains, said modified glycogen being obtained by the process of the invention.
- the starch modified in accordance with the present invention can be used directly or hydrolyzed in order to produce oligosaccharides of interest
- starch modified in accordance with the invention can make it possible to reduce the quantities of enzymes necessary for such hydrolysis.
- starch modified in accordance with the invention can be used during the manufacture of various foods, in particular as an additive which increases the viscosity or promotes the formation of a gel.
- the starch modified according to the invention can also be used in many industries: paper and cardboard industry, adhesive industry, textile industry, pharmaceutical industry (for the formulation of drugs), etc.
- the starch modified in accordance with the invention may also undergo other modifications, in particular chemical modifications such as acid treatment, oxidation, esterification, etc. before its use.
- the present invention also relates to the use of this modified starch or of this modified glycogen for the preparation of derived products, in particular food products.
- the present invention also relates to the products thus prepared comprising modified starch differing from starch produced naturally by plants by the length of its external chains or modified glycogen differing from glycogen produced naturally by the length of its external chains .
- FIG. 1 represents a simplified diagram of the metabolism of starch hitherto known to a person skilled in the art. All the stages described are compartmentalized in the plastid.
- Glc glucose
- FIG. 2 represents a simplified diagram of the synthesis of amylopectin, in which the role of the enzyme D is highlighted.
- BE branching by branching enzymes
- DBE isoamylase disconnection
- MOS release of oligosaccharides
- G-6-P glucose-6-phosphate
- Glc glucose
- the energy cost of splicing with DBE and the enzyme D described in this invention is 2 ATP per glucan cleaved and reintroduced into amylopectin in ⁇ (WSP 111 ). This cost stems from the reactivation of the glucose produced by the enzyme D into ADP-glucose.
- the dotted line drawn from WSP 1 "illustrates the possibility offered to the polysaccharide of reserving elongation substrate as long as the structure required for insolubilization in the grain has not been reached.
- the entry and exit of the cycle are illustrated by the arrows in bold lines and are formed on the one hand by the synthesis of ADP-glucose and on the other hand by the crystallization and insolubilization of the polysaccharide on the surface of the grain.
- amyloidosis occurs after insolubilization and is carried out exclusively in the granule.
- FIG. 3A represents the length distribution of the non-disconnected soluble oligosaccharides accumulated by the mutant strain JV45J of Chlamydomonas reinhardtii.
- FIG. 3B represents the length distribution of the chains of the amylopectin disconnected from the wild Chlamydomonas reinhardtii strain.
- FIG. 3C represents the distribution of lengths of the chains of the amylopectin disconnected from the mutant strain JV45J Chlamydomonas reinhardtii.
- FIG. 3D represents the distribution of chain lengths of the amylopectin disconnected from “waxy” maize with the pure enzyme D from Chlamydomonas reinhardtii in the absence of oligosaccharides.
- FIG. 4 represents the incorporation of maltooligosaccharides on the amylopectin of the wild strain of Chlamydomonas reinhardtii.
- FIG. 5 represents the separation of amylopectin and amylose from the starches of JV45J (sta11-1) and 137C (wt) on filtration chromatography on CL-2B gel.
- the JV45J mutant is represented by radiolabelled starch (DPM) and the 137C strain is represented by absorbance.
- the residual starch has a new modified structure characterized by an amylose enrichment and by an amylopectin whose ultra-short chains (approximately 2, 3, or 4 glucose residues) are superabundant relative to the chains of medium length (approximately from 9 to 18 glucose residues) (Examples 2 and 31
- this mutant lacks a 62kD protein normally present in wild strains of Chlamydomonas reinhardtii, identified this protein as being a 4- ⁇ -D-glucanotransferase (enzyme D), and have demonstrated new functions of this enzyme D with respect to the polysaccharides (Example 4). These results can be used to obtain transgenic plants producing polysaccharides (starch, glycogen) modified (Example 5). The authors of the present invention have further demonstrated the role of the enzyme D in the degradation of malto-oligosaccharides by phosphorylase (Example 6).
- the yellow areas contain less than 12% of the amount of starch accumulated by the black areas.
- the olive color observed in certain sparsely colored areas suggests the existence of a residual starch enriched in amylose.
- those which displayed complementation in trans were selected with mutants carrying sta-1, sta6-1 :: ARG7, sta7-1 :: ARG7, sta5-1 which are defective for the loci coding for the large and the small AGPase subunit (STA1 and STA6) for the 88 kDa isoamylase (STA7) or for plastid phosphoglucomutase (STA5).
- JV45J A new type of mutant (JV45J), which accumulates 4% of the normal amount of starch, has thus been isolated.
- the character responsible for the defective phenotype behaves like a recessive Mendelian character in view of segregation after crossing, and defines a new genetic locus named STA11, since the mutation complements in trans and recombines with all of the defects tested.
- the polysaccharides present in strains carrying
- Granular starch Granular starch and soluble glucans were analyzed separately. The starch dispersed in aqueous DMSO and defatted by precipitation with four volumes of ethanol was resuspended in 10 mM NaOH to then be fractionated by molecular sieving chromatography on CL2B sepharose gel.
- Amylose and amlyopectin composition (gel filtration). The separation of amylopectin and amylose is effected by gel filtration of the mutant strain JV45J and the wild-type reference 137C. The starch dissolved in 10 mM NaOH was fractionated by molecular sieving chromatography according to the method described by Delrue et al. (1992). A sample of each fraction was stained with iodine and the full spectrum of the polysaccharide-iodine complex was recorded. Amyloglucosidase assays revealed the presence of 30% amylose (15% for the wild reference).
- amylopectin is characterized by a ⁇ max of the polysaccharide-iodine complex which increased from 20 to 30 nm (from 550 to 570-580 nm). This last characteristic is found in a large number of starches enriched in amylose.
- the gel filtration profiles described show a doubling of the amount of amyloidosis in the mutant compared to the wild type as well as an apparent modification of the chain length distribution of the amylosic fraction.
- a new analysis of segregation of amylopectin and amylose on filtration chromatography on CL-2B gel was carried out using 500 ⁇ g of starch from JV45J (sta11-1) labeled with 14 C and 10 mg of starch of 137C.
- the results (Fig. 5) tend to confirm the data from the co-segregation study, that is to say a reduction in the length of the amylose chains produced by the strain JV45J; amyloidosis therefore appears to be more abundant and of less mass.
- a radioactive count and absorbance are determined for each fraction.
- the column is eluted in 10 mM sodium hydroxide.
- X-ray diffractograms show a change in the crystalline lattice of the wild type A of high crystallinity towards a mixture of types A and B of much weaker crystallinities.
- the shape of the granules is particularly altered and their overall size is reduced.
- the wild strain generally has grains with a smooth surface while the mutant has grains of smaller size with a rough and irregular grain surface.
- Soluble glucans small malto-oligosaccharide
- the fraction of soluble glucans (WSP) was subjected to a triple extraction with chloroform methanol. The aqueous phase was lyophilized and the dry pellet redissolved in a buffer and fractionated by molecular sieving chromatography on a TSK-HW-50 column as described by Mouille et al., 1996.
- WSP soluble fractions purified at From mutants deficient in isoamylase, no phytoglycogen or other soluble polysaccharide of significant mass was found.
- the WSP fraction accumulated by the sta11 mutants consists exclusively of low-branched oligosaccharides (less than 1.5% of branches) of low mass (FIG. 3A).
- amylose and amylopectin fractions obtained by molecular sieving chromatography were then subjected to an enzymatic disconnection with isoamylase followed by an electrophoretic separation of the disconnected chains.
- the results illustrated in FIG. 3 establish the novelty of the structure presented by the amylopectin of the JV45J strain. Indeed, amylopectin has an increase in chains traditionally absent from the structure.
- This study involves quantitative and qualitative measurements of enzymatic activities, in parallel with kinetic characterizations and analyzes of the elution profiles on Mono-Q anion exchange columns (FLPC chromatography).
- the enzymes tested are as follows: ADP- glucose pyrophosphorylase, phosphoglucomutase, soluble starch synthetase I, soluble starch synthetase II, granule-linked starch synthetase, branching enzymes (two types), branching enzymes (pullulanase and isoamylase), phosphorylases and all starch hydrolases which can be detected in zymogram gels containing starch. No qualitative or quantitative difference in these enzymatic activities co-aggregated with the mutant gene.
- Purification of the enzyme and glucan transfer activity requires 20 liters of culture of a wild strain of Chlamydomonas reinhardtii in TAP medium (Harris, 1989) for three days in order to obtain a cell density of 2 ⁇ 10 6 cells per ml. After centrifugation at 3000 rpm for 10 minutes, the cell pellet is passed twice to the French press and immediately frozen at -80 ° C. This raw thawed extract is centrifuged for 20 minutes at 1000 rpm at 4 ° C. The proteins in the extract (350 to 500 mg) are dosed by the Bradford method (Bio-rad assay kit).
- the supernatant is precipitated with 5% protamine sulfate (40 ⁇ l per ml of extract 15 minutes in ice) then centrifuged at 10,000 rpm for 20 minutes at 4 ° C.
- the supernatant (200 to 400 mg of protein) is injected using a multi-injection program on a MonoQ ion exchange column (Pharmacia HR 10/10 with a volume of 9 ml, flow rate: 2 ml. Min "1 ) balanced in a 50 mM sodium acetate buffer, 2 mM DTT (pH 6 with acetic acid).
- the fraction not retained (40 to 70 mg) undergoes a first precipitation with 30% ammonium sulphate (176 mg / ml) 45 minutes at 4 ° C. and is then centrifuged at 1000 rpm for 20 minutes.
- the supernatant (30 to 60 mg) is then precipitated at 50% 45 minutes at 4 ° C (126 mg / ml) and is then centrifuged at 10,000 rpm for 20 minutes.
- the pellet (10 to 20 mg of protein) is resuspended in 2 ml of 50 mM sodium acetate buffer, 2 mM DTT pH 6 and then injected on filtration gel
- ⁇ -amylases are processive enzymes which selectively digest the outer chains of polysaccharides, the result obtained shows that major modifications are restricted to chains external of the polymer. It is important to note that no oligosaccharide is released in the process while the amount of ⁇ -1, 6 bonds remains constant.
- the 62kD enzyme is therefore an ⁇ -1,4 glucanotransferase, the function of which is to cleave the ⁇ -1,4 bonds present on the external chains of the amylopectin donor in order to transfer them to the non-reducing ends of chains neighboring the outside of the acceptor. .
- the only ⁇ -1, 4 glucanotransferases known to be present during the synthesis of starch are commonly called enzymes D.
- the reaction consists of cleavage of a donor glucan and a transfer to a receptor chain.
- the action of the identified 62 kD enzyme was also tested on glucose, maltose, maltotriose, maltotetraose, maltopentaose, maltohexaose and maltoheptaose the enzyme successfully disproportionates all oligosaccharides longer than maltose and glucose, on which it has no action. Its effects on maltotriose have been described in Figure 3E. The very small amounts of maltose in all cases confirm that the enzyme obeys the rules presented above defining the action of disproportionate enzymes.
- the purification protocol for enzyme D can be modified, for example according to the following variant:
- the supernatant obtained after centrifugation of the crude extract as described in Example 3 is precipitated with protamine sulfate (50 ⁇ l of 10% protamine sulfate per ml of extract 15 minutes in ice) and then centrifuged at 10,000 rpm for 20 minutes at 4 ° C.
- the supernatant (200 to 400 mg of protein) is then injected using a multi-injection program on a MonoQ anion exchange column (Pharmacia HR10 / 10 with a volume of 9 ml, flow rate: 2 ml. Min “1 ) coupled to a UNO-S12 cation exchange column (BIO-RAD with a volume of 12 ml, flow rate: 2 ml. min "1 ).
- a MonoQ anion exchange column Pharmacia HR10 / 10 with a volume of 9 ml, flow rate: 2 ml. Min "1
- UNO-S12 cation exchange column BIO-RAD with a volume of 12 ml, flow rate: 2 ml. min "1 ).
- These two columns are balanced in a 50 mM sodium acetate buffer, 2 mM DTT (pH 6 with acetic acid).
- the elution is carried out in a 30 min level at 5% NaCl.
- the fractions of interest
- the activity thus purified manifests itself at an optimum pH between pH5 and pH7.5 and decreases significantly above pH9.
- the zymogram system fairly well mimics the synthesis of polysaccharide on the surface of the starch granule in that it allows the oligosaccharides to diffuse freely in a large volume of buffer while the polysaccharide is retained in a small volume of the gel, where a strong specific enzymatic activity is manifested.
- Oligosaccharides are radioactively labeled with 14 C by in vivo disconnection of the labeled amylopectin. It was verified that the distribution of the length of the chains in the mixture of disconnected chains corresponded to that presented in FIG. 3B.
- calluses are obtained from immature embryos of genotype H1 II or (A188 x B73) according to the method and on the media described by Armstrong (1994). The calluses thus obtained are multiplied and maintained by successive subcultures every fortnight on the initiation environment.
- Seedlings are then regenerated from these calluses by modifying the hormonal and osmotic balance of the cells according to the method described by Vain et al (1989). These plants are then acclimatized in the greenhouse where they can be crossed or self-fertilized.
- the previous paragraph describes obtaining and regenerating cell lines for transformation.
- a method of genetic transformation leading to the stable integration of the modified genes into the genome of the plant is based on the use of a particle gun.
- the target cells are fragments of calluses described in the paragraph A. These fragments with a surface of 10 to 20 mm 2 were placed, 4 hours before bombardment, at the rate of 16 fragments per dish in the center of a Petri dish containing a culture medium identical to the initiation medium , supplemented with 0.2 M mannitol + 0.2 M sorbitol.
- the plasmids carrying the nucleotide sequences to be introduced such as the cDNA coding for the potato enzyme D (Takada et al., 1993) or the antisense sequences obtained from this cDNA are purified on a Qiagen column, following manufacturer's instructions. They are then precipitated on tungsten particles (M10) following the protocol described by Klein et al (1987). The particles thus coated are projected towards the target cells using the cannon and according to the protocol described by J. Finner (1992).
- the callus boxes thus bombarded are then sealed using ®Scellofrais, then grown in the dark at 27 ° C.
- the first subculture takes place 24 hours later, then every fortnight for three months on medium identical to the initiation medium added with a selective agent.
- the selective agents which can be used generally consist of active compounds of certain herbicides (®Basta, ®Roundup) or certain antibiotics (Hygromycin, kanamycin, etc.).
- Calls are obtained after three months or sometimes earlier, calluses whose growth is not inhibited by the selection agent, usually and mainly composed of cells resulting from the division of a cell having integrated into its genetic heritage one or more copies of the selection gene.
- the frequency of obtaining such calluses is about 0.8 cal for bombarded can.
- These calluses are identified, individualized, amplified and then cultivated so as to regenerate seedlings. In order to avoid any interference with untransformed cells, all of these operations are carried out on culture media containing the selective agent.
- the plants thus regenerated are acclimatized and then cultivated in a greenhouse where they can be crossed or self-fertilized.
- amylomaltase an ⁇ -1,4 glucanotranferase similar to enzyme D, increases the production of glucose-
- JV45J from Chlamydomonas, demonstrated a stimulation of at least a factor of 5, in the presence of enzyme D, of the degradation of maltotetraose and maltotriose by phosphorylase. Knowing that the production of glucose-1-phosphate from glucan of length DP5 is found in both bacteria and plants, the enzyme D could also facilitate the action of phosphorylase in plants.
- the isolation of genomic sequences coding for the enzyme D of Chlamydomonas followed the following protocol: a sequence alignment carried out between Solanum tuberosum, Streptococcus pneumoniae, Mycobacterium tuberculosis and Clostridium butyricum, made it possible to choose oligonucleotides corresponding to the conserved regions (regions 1 and 2), to serve as primers for PCR reactions.
- a 16-nucleotide extension containing the restriction sequences of 3 different enzymes was added in 5 '[EcoRI, Sacll, Notf].
- This PCR product is extracted from a 0.8% TAE gel according to the PROLABO "DNA Purification Kit” protocol, and placed in the multiple cloning site of the pBlueskipt II SK piasmide at the NotI site.
- a transformation of the Escherichia coli XL1-Blue strain made competent then allows the amplification of the clone.
- a rapid sequencing of 1.6 kb (between primers T3 and T7) according to the Sanger method was then carried out (SEQ ID No. 1).
- the cloning in the mutant sta11-1 of the region corresponding to the gene for the enzyme D can be carried out, to determine the nature of the mutation leading to the absence of the protein in the mutant cell.
- a comparative analysis of the wild and mutant sta11-1 strains under nitrogen deficient or normal conditions shows that the expression of the mutant sta11-1 phenotype is partially conditional. This indicates that the expressiveness of the mutation on the phenotype can vary depending on physiological conditions for the same organism. It is possible that these variations in expressiveness of the phenotype can be found from one plant species to another. It is possible to find conditions in which the decrease in the amount of starch does not occur while phenotypic modifications are observed (presence of oligosaccharides, modification of the structure of amylopectin).
- a Ap ⁇ max, wavelength of the maximum absorbance of an iodized polysaccharide complex of amylopectin purified by gel filtration.
- b quantity of insoluble polysaccharide, expressed in ⁇ g. 10 "6 cells, purified by sedimentation (measurement by standard assay of Pamyloglucosidase).
- MOS quantity of soluble malto-oligosaccharides, expressed ⁇ g. 10 " 6 cells. 0.5 ⁇ g. 10 "6 cells corresponds to a plastid concentration of 10 mM if all the MOS were to be considered as maltotriose
- d The percentage of amylose in the purified starch was calculated by gel filtration of the dispersed polysaccharides.
Landscapes
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Genetics & Genomics (AREA)
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Zoology (AREA)
- Organic Chemistry (AREA)
- Bioinformatics & Cheminformatics (AREA)
- Biotechnology (AREA)
- Molecular Biology (AREA)
- Wood Science & Technology (AREA)
- General Engineering & Computer Science (AREA)
- Biomedical Technology (AREA)
- Nutrition Science (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- Microbiology (AREA)
- Medicinal Chemistry (AREA)
- Cell Biology (AREA)
- Physics & Mathematics (AREA)
- Biophysics (AREA)
- Plant Pathology (AREA)
- Preparation Of Compounds By Using Micro-Organisms (AREA)
- Micro-Organisms Or Cultivation Processes Thereof (AREA)
- Breeding Of Plants And Reproduction By Means Of Culturing (AREA)
- Polysaccharides And Polysaccharide Derivatives (AREA)
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA002331153A CA2331153A1 (fr) | 1998-06-16 | 1999-06-16 | Procede d'obtention de polysaccharides modifies |
AU41511/99A AU772062B2 (en) | 1998-06-16 | 1999-06-16 | Method for obtaining modified polysaccharides |
US09/719,978 US6858717B1 (en) | 1998-06-16 | 1999-06-16 | Method for obtaining modified polysaccharides |
EP99925114A EP1088089A1 (fr) | 1998-06-16 | 1999-06-16 | Procede d'obtention de polysaccharides modifies |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR98/07589 | 1998-06-16 | ||
FR9807589A FR2779740B1 (fr) | 1998-06-16 | 1998-06-16 | Procede d'obtention d'amidon modifie |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1999066056A1 true WO1999066056A1 (fr) | 1999-12-23 |
Family
ID=9527459
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/FR1999/001446 WO1999066056A1 (fr) | 1998-06-16 | 1999-06-16 | Procede d'obtention de polysaccharides modifies |
Country Status (6)
Country | Link |
---|---|
US (1) | US6858717B1 (fr) |
EP (1) | EP1088089A1 (fr) |
AU (1) | AU772062B2 (fr) |
CA (1) | CA2331153A1 (fr) |
FR (1) | FR2779740B1 (fr) |
WO (1) | WO1999066056A1 (fr) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
BRPI0415764A (pt) | 2003-11-28 | 2006-12-26 | Eastman Chem Co | interpolìmero, produto de reação, métodos para converter uma hidroxila, para preparar uma forma estável de um interpolìmero, para converter um álcool primário, e para tratar um mamìfero necessitado do mesmo, composições para revestimento e farmacêutica oral, dispersão de pigmento, e, artigo |
CA2606220A1 (fr) * | 2005-04-19 | 2006-12-21 | Basf Plant Science Gmbh | Expression specifique de l'albumen farineux et/ou de l'embryon en germination dans des plantes monocotyledonees |
ES2700662T3 (es) | 2010-11-15 | 2019-02-18 | Agrana Staerke Gmbh | Composición de adhesivo a base de almidón |
CN114907493B (zh) * | 2022-05-30 | 2023-09-08 | 江南大学 | 一种阳离子超支化淀粉基基因载体及其制备方法和应用 |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1996027674A1 (fr) * | 1995-03-08 | 1996-09-12 | Hoechst Schering Agrevo Gmbh | Amidon modifie d'origine vegetale, vegetaux synthetisant cet amidon, et son procede de production |
-
1998
- 1998-06-16 FR FR9807589A patent/FR2779740B1/fr not_active Expired - Fee Related
-
1999
- 1999-06-16 WO PCT/FR1999/001446 patent/WO1999066056A1/fr not_active Application Discontinuation
- 1999-06-16 AU AU41511/99A patent/AU772062B2/en not_active Ceased
- 1999-06-16 CA CA002331153A patent/CA2331153A1/fr not_active Abandoned
- 1999-06-16 US US09/719,978 patent/US6858717B1/en not_active Expired - Fee Related
- 1999-06-16 EP EP99925114A patent/EP1088089A1/fr not_active Withdrawn
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1996027674A1 (fr) * | 1995-03-08 | 1996-09-12 | Hoechst Schering Agrevo Gmbh | Amidon modifie d'origine vegetale, vegetaux synthetisant cet amidon, et son procede de production |
Non-Patent Citations (2)
Title |
---|
BULÉON A ET AL.: "Starches from A to C", PLANT PHYSIOLOGY, vol. 115, no. 3, November 1997 (1997-11-01), pages 949 - 957, XP002096248 * |
FUCHS B ET AL.: "Disproportionating transglycosylase (D-enzyme) in green algae and cyanobacteria: Partial purification and characterization.", ZEITSCHRIFT FUER NATURFORSCHUNG SECTION C BIOSCIENCES, (1994) VOL. 49,NO. 3-4, pages 163 - 170, XP002096249 * |
Also Published As
Publication number | Publication date |
---|---|
AU772062B2 (en) | 2004-04-08 |
US6858717B1 (en) | 2005-02-22 |
FR2779740A1 (fr) | 1999-12-17 |
FR2779740B1 (fr) | 2002-06-28 |
AU4151199A (en) | 2000-01-05 |
EP1088089A1 (fr) | 2001-04-04 |
CA2331153A1 (fr) | 1999-12-23 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
AU699552B2 (en) | DNA sequences coding for enzymes capable of facilitating the synthesis of linear alpha-1,4 glucans in plants, fungi and microorganisms | |
US6483010B1 (en) | DNA molecules encoding enzymes involved in starch synthesis, vectors, bacteria, transgenic plant cells and plants containing these molecules | |
US6207880B1 (en) | Plants which synthesize a modified starch, process for the production thereof and modified starch | |
AU730569B2 (en) | Nucleic acid molecules encoding starch phosphorylase from maize | |
US6825342B1 (en) | Plant starch composition | |
US6791010B1 (en) | Nucleic acid molecule coding for beta-amylase, plants synthesizing a modified starch, method of production and applications | |
US6794558B1 (en) | Nucleic acid module coding for αglucosidase, plants that synthesize modified starch, methods for the production and use of said plants, and modified starch | |
EP0868520B1 (fr) | Nouveaux amidons obtenus par modification de l'expression de genes d'enzymes biosynthetiques d'amidon | |
AU715054B2 (en) | Nucleic acid molecules from plants coding enzymes which participate in the starch synthesis | |
CA2378173A1 (fr) | Molecules d'acide nucleique issues de vegetaux codant pour des enzymes participant a la synthese de l'amidon | |
HUT77470A (hu) | Növényekből származó elágazást megszüntető enzimeket kódoló DNS molekulák | |
CZ20011125A3 (cs) | Molekuly nukleových kyselin, které kódují rozvětvovací enzym z bakterie rodu Neisseria, a způsob výroby alfa-1,6- rozvětvených alfa-1,4 glukanů | |
JP2003501020A (ja) | アミロスクラーゼタンパク質および分枝酵素の活性を上昇させた遺伝子改変植物の細胞および植物体 | |
CA2560655A1 (fr) | Procede d'amelioration des plantes | |
WO1999066056A1 (fr) | Procede d'obtention de polysaccharides modifies | |
EP1179078B1 (fr) | Grains d'amidon contenant un polypeptide recombinant d'interet, leur procede d'obtention, et leurs utilisations | |
JPH11514521A (ja) | 改変植物及び植物産物 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A1 Designated state(s): AE AL AM AT AU AZ BA BB BG BR BY CA CH CN CU CZ DE DK EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MD MG MK MN MW MX NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT UA UG US UZ VN YU ZA ZW |
|
AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): GH GM KE LS MW SD SL SZ UG ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE BF BJ CF CG CI CM GA GN GW ML MR NE SN TD TG |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
DFPE | Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101) | ||
WWE | Wipo information: entry into national phase |
Ref document number: 1999925114 Country of ref document: EP |
|
ENP | Entry into the national phase |
Ref document number: 2331153 Country of ref document: CA |
|
WWE | Wipo information: entry into national phase |
Ref document number: 41511/99 Country of ref document: AU |
|
WWP | Wipo information: published in national office |
Ref document number: 1999925114 Country of ref document: EP |
|
REG | Reference to national code |
Ref country code: DE Ref legal event code: 8642 |
|
WWE | Wipo information: entry into national phase |
Ref document number: 09719978 Country of ref document: US |
|
WWG | Wipo information: grant in national office |
Ref document number: 41511/99 Country of ref document: AU |
|
WWW | Wipo information: withdrawn in national office |
Ref document number: 1999925114 Country of ref document: EP |