JP2001037358A - Cotton plant improved in cotton fiber characteristics, method for creating the same and production of cotton fiber from the cotton plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain cotton plants suitable for producing high quality textiles and the likes excellent in strengths and dyeability by stably maintaining a specific exogeneous catalase gene and producing cotton fibers improved in fiber characteristics such as fiber denier, uniformity in fiber lengths and the like. SOLUTION: Cotton fibers stably maintaining an exogeneous catalase gene having (A) a base sequence which is under control of a promoter capable of functioning in cotton fibers and expressed by 57-1541 base number in the base sequence expressed by the formula or (B) a base sequence capable of hybridizing with the aforesaid base sequence under a stringent condition and improved in fiber characteristics compared with those of wile-type strains are produced. This cotton plant belonging to the genus Gossypium is a transgenic plant obtained by transforming the wild-type strain with an expressgxon vector containing the aforesaid exogeneous catalase gene. The cotton fibers improved in fiber characteristics compared with those of the wild-type strains are preferably produced by harvesting seeds obtained by self-pollination of those cotton plants and separating cotton fibers from seed coats of the seeds.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cotton plant that produces cotton fibers having improved fiber characteristics as compared to wild strains, and more particularly to increased fiber fineness (thickness) and fiber length uniformity (short fiber length). The present invention relates to a cotton plant that produces cotton fiber having fiber characteristics such as content. The present invention also relates to a method for producing the cotton plant and a method for producing a cotton fiber having improved fiber characteristics from the cotton plant.

[0002]

2. Description of the Related Art Usually, cotton fiber is Gossypiu.
m) It is produced by cultivating a cotton plant belonging to the genus and collecting it from the obtained fruit (cotton ball). Cotton fibers are epidermal cells of seed coat
Are differentiated single cells, elongation initiation (initiation),
Elongation, secondary cell wall thickening (secondary cell)
It grows through four stages: wall thickening and maturation. More specifically, the elongation of the cotton fiber is
The epidermal cells of the ovule begin to elongate the fiber immediately after flowering, and thereafter the fiber elongates rapidly, and the elongation is completed about 25 days after flowering. Thereafter, the elongation of the fiber is stopped, a secondary cell wall is generated, and a mature cotton fiber is obtained after ripening.

[0003] There are many varieties of cotton plants, and cotton fibers having different fiber characteristics are obtained, and are used depending on various uses. There are various property parameters that indicate fiber properties, but fiber length,
Fineness, strength, and fiber length uniformity are listed. Conventionally, great efforts have been made to improve the properties of cotton fibers, but the main factors for improving the fiber properties have been fiber length and fineness. Among them, longer and thinner fibers have been desired.
As a variety having such fiber properties, sea-island cotton is famous, but its productivity is low and it is very expensive. If cotton fibers having fiber properties equal to or higher than sea-island cotton can be obtained with higher productivity, it is very useful in industry.

Means for improving fiber properties and / or productivity are roughly divided into (1) breeding by crossing, (2) treatment with plant hormones, and (3) genetic recombination technology. There are three types of breeding.

[0005] Breeding by crossing has been the most widely used in the past, and the current cultivars of cotton plants have been bred by this method. However, this method can only introduce useful traits from closely related species,
The degree of change is low in spite of the time required, and a remarkable improvement cannot be expected particularly with regard to the characteristics of the cotton fiber or the yield of the cotton fiber.

[0006] Plant hormones such as auxin, gibberellin, cytokinin, and ethylene have been widely put to practical use for regulating the growth of crops and horticultural plants. The effects of plant hormones on the fiber properties of cotton plants, especially the mechanism of fiber elongation, are known for gibberellins, auxins, brassinosteroids, etc., but in fact, sufficient effects have been obtained to the extent that they can be used industrially. At present, it has not been put to practical use.

On the other hand, in recent years, there has been remarkable progress in genetic recombination technology in the field of plant breeding. Introducing a specific useful foreign gene into various plants (for example, cotton, soybean, corn, tomato, etc.). Many examples have been reported in which the expression of the plant successfully imparts the desired useful trait to the plant.

[0008] Even in cotton plants, insect-resistant recombinant cotton into which a BT toxin [insecticidal protein toxin produced by Bacillus thuringiensis] gene has been introduced,
A herbicide (glyphosate) -resistant recombinant cotton or the like in which a 5-enolpyruvylshikimate-3-phosphate synthase gene has been introduced has been developed and is already commercialized. It is said that the majority has already been reached).

Similarly, instead of a pest resistance gene or a herbicide resistance gene, a gene involved in the formation or elongation of a cotton fiber is introduced into a cotton plant and expressed in a large amount, so that its fiber characteristics or productivity can be improved. It is expected to improve dramatically. Conversely, it is theoretically possible to change the fiber properties by incorporating an antisense gene and suppressing the function of the endogenous gene. A method using such a genetic engineering technique is expected to be able to more reliably control fiber elongation and formation in a short period of time as compared with conventional breeding by crossing and selection.

[0010] However, in order to obtain cotton fibers having desired fiber properties by genetic recombination technology, the mechanism of fiber elongation and formation is clarified at the gene level.
Although it is essential to determine the genes that are closely involved in those mechanisms, at this time there is very little molecular biology knowledge about such genes. Although many studies have been made on the cell elongation of plants, there are still many unclear points on its control factors, and its control mechanism has not been elucidated until now.

However, there is no report on genes involved in elongation or formation of cotton fibers. For example, John et al. Used a Differential Screening method on the 15th and 24th day of flowering.
E expressed preferentially in the fiber structure of day
Six genes (Maliyakal E. John and Laura J. Crow, Pro
Natl. Acad. Sci. USA, 89, 5769-5773 (1992)) and the H6 gene (Maliyakal E. John and
Greg Keller, Plant physiol., 108, 669-676 (1995))
Was isolated. In addition, John introduced the E6 gene into a cotton plant in an antisense form, suppressed the expression level of the endogenous E6 gene, and examined the effect of the E6 gene on cotton fiber properties (Maliyakal E. Jhon, Plant Molecular Biology,
30, 297-306 (1996)). However, E6RN in the fiber tissue
They reported that fiber length, strength and fineness did not change significantly, despite the decreased expression level of A, concluding that the E6 gene was not important for cotton fiber development. On the other hand, Song et al. Used the differential display method (Diff
erential Display), a cDNA encoding an acyl carrier protein (ACP) specifically expressed in cotton fiber tissue was identified from cotton plants (Ping Song, Randy).
D. Allen, Biochimica et Biophysica Acta, 1351, 30
5-312 (1997)). In addition, cDNA for the catalytic subunit of cellulose synthase has been isolated as a gene relating to cellulose synthesis of cotton fiber (Julie R. Pear, Yasus
hi Kawagoe, et al, Proc. Natl. Acad. Sci. USA, 93,
12637-12642 (1996)).

[0012] Further, there have been reported some examples of the production of recombinant cotton plants into which a gene which is suggested to be involved in fiber properties is introduced. For example, Agracetus in the U.S. has improved fiber strength by connecting a peroxidase gene, which is thought to be related to ovule and fiber development, to a cotton plant downstream of the promoter of a fiber-specific gene, thereby improving fiber strength. It is reported that a recombinant cotton plant that produces cotton fiber has been developed (International Publication WO95 / 08914). The present inventors also isolated and identified five types of genes specifically expressed during cotton fiber elongation from cotton plants by differential screening and differential display (Japanese Patent Application Laid-Open No. 9-75093). By introducing the KC22 gene, one of the above, into a cotton plant, a recombinant cotton plant producing a cotton fiber with an improved fiber length has been obtained.

However, as described above, only a very small number of genes specifically expressed during the formation and elongation of cotton fibers have been isolated. At present, little is known about whether it plays an important role in determining each parameter of cotton fiber characteristics such as length, fiber strength, fineness, and fiber length uniformity. Furthermore, there has not yet been reported a recombinant cotton plant that produces cotton fibers having improved characteristic parameters such as fiber fineness and fiber length uniformity.

[0014]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a gene involved in elongation and formation of cotton fibers, especially fiber fineness (fiber thickness) and fiber length uniformity (short fiber content). The purpose of the present invention is to produce a recombinant cotton plant having improved cotton fiber characteristics by screening for a gene that plays an important role in the determination of cotton fiber characteristics and artificially controlling the expression of the gene. It is another object of the present invention to provide a method for producing cotton fibers having improved fiber properties from the cotton plant.

[0015]

Means for Solving the Problems As a result of the present inventors' earnest efforts to achieve the above-mentioned object, the catalase gene was introduced into cotton plants and overexpressed in the cotton fibers to obtain a fineness of the cotton fibers. And improved characteristic parameters such as fiber length uniformity, and succeeded in producing cotton fibers with improved fiber properties by harvesting and isolating cotton fibers from this recombinant cotton plant. As a result, the present invention has been completed.

That is, the present invention is as follows. 1. Cotton plants belonging to the genus Gossypium, in particular stably retaining an exogenous catalase gene under the control of a promoter capable of functioning in cotton fibers, and producing cotton fibers having improved fiber properties compared to wild strains, especially And a transgenic plant obtained by transforming the wild-type strain with an expression vector containing an exogenous catalase gene under the control of a promoter capable of functioning in cotton fiber. 2. The above cotton plant which is homozygous for the catalase gene, in particular, the above cotton plant in the form of a seed. 3. A cotton fiber obtained from the cotton plant and having improved fiber properties as compared to a wild strain. 4. An expression vector containing an exogenous catalase gene under the control of a promoter capable of functioning in a cotton fiber, comprising the step of transforming cells of a wild plant of the genus Gossypium, comprising the steps of: A method for producing a cotton plant producing a cotton fiber having fiber properties, particularly the method further comprising a step of regenerating a plant from the transformed cell. 5. The following steps: (1) Transforming cells of a wild plant of cotton belonging to the genus Gossypium with an expression vector containing an exogenous catalase gene under the control of a promoter capable of functioning in cotton fiber;
(2) a cotton plant (R) that produces, from the transformed cells, cotton fibers having improved fiber properties as compared to the wild type;
0), (3) self-pollination of the seed from the plant, and (4) the catalase gene in a seed obtained by self-pollination from a cotton plant (R1) obtained by cultivating the seed. A method for producing a cotton plant in which a trait that produces a cotton fiber that is homozygous for the catalase gene and has improved fiber properties as compared to the wild strain is fixed, which comprises testing the separation ratio of the catalase gene. 6. A method for producing cotton fiber having improved fiber characteristics as compared with a wild strain, comprising a step of collecting a seed obtained by self-pollination of any of the above cotton plants and separating the cotton fiber from the seed coat of the seed.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The cotton plant of the present invention is not particularly limited as long as it belongs to the genus Gossypium and is derived from a plant that produces cotton fiber. For example, G. hirsutum (G. hirsutum) , Gossypium barbadense, G. arboreum, G. anomalu
lum), Gossypium almurianum (G. armourianu)
m), G. klotzchianum
), Gossypium herbaceum (G. herbaceum), Gossypium lemonday (G. raimondii) and the like.

[0018] The "cotton plant" used herein refers to a plant containing matured cotton fiber in its fruit, and a cotton fiber equivalent to the plant even before or after the formation of the cotton fiber. Growing cotton plant capable of producing the same, a cotton plant cell or tissue capable of differentiating into the immature cotton plant, and a seed collected from the cotton plant (provided that the seed is obtained by cultivating the seed. Plant that produces the same cotton fiber as the parent).

In the present invention, the term "wild strain" means any cotton plant having no exogenous catalase gene on its genome. Therefore, in addition to so-called wild species, cultivars established by ordinary crossing, natural or artificial mutants thereof, and transgenic cotton plants into which an exogenous gene other than catalase has been introduced are included.

In the present invention, "cotton fiber having improved fiber properties" refers to at least one of various parameters usually used for evaluating fiber properties, such as fiber length, fineness, fiber strength, and fiber length uniformity. One implies an improved cotton fiber compared to the wild strain. Preferably, the cotton plant of the present invention produces a cotton fiber in which at least one characteristic parameter of fiber fineness and fiber length uniformity is improved as compared with a wild strain. More preferably, the cotton plant of the present invention produces a cotton fiber in which both the fiber fineness and the fiber length uniformity are improved as compared with the wild strain.

The cotton plant of the present invention is a plant in which an exogenous catalase gene has been introduced into these wild plants of the genus Gossypium by genetic engineering techniques and stably retained. Here, "stably retained" means that at least the catalase gene is expressed in the cotton fiber produced by the current plant into which the catalase gene has been introduced, thereby improving the fiber properties of the cotton fiber. For a period of time, it means that it is retained in the cotton plant cells. Therefore, in practice, the catalase gene needs to be integrated on the chromosome of the host cotton plant. More preferably, the catalase gene is stably inherited in the next generation.

Most plant catalase is a detoxifying enzyme that is localized in microbodies and breaks down metabolically produced toxic H ₂ O ₂ into water and oxygen. However, its function in plants has not been fully elucidated. Catalase is used in cold adaptation and pathogen resistance of plants (Sanchez-Casas, P. an
d Klessing, DF Plant Physiol., 106, 1675-1679 (1
994), Prasad, TK, Anderson, MD, et al, Plant
Cell, 6, 65-74 (1994)), but there has been no report on the relationship between catalase and the fiber properties of cotton plants.

In the present invention, "catalase gene"
Is the decomposition reaction of hydrogen peroxide (2H_TwoO _Two→ O_Two+ 2H_Two
Base sequence encoding the amino acid sequence of the enzyme that catalyzes O)
DNA with columns. The origin of the catalase gene
No restrictions, already cloned and readily available
Catalase genes can be used. The catala
Gene is mRNA (or cDNA library)
Genomic DNA library
Genomic DNA obtained from the library,
Alternatively, it may be by chemical synthesis. Preferably
Means that the catalase gene is of plant origin, more preferably
It is a gene derived from dough (See Reference Example 1 below,
This shows the procedure for cloning catalase cDNA).

As a preferred example of the catalase gene used in the present invention, a DNA having a nucleotide sequence represented by nucleotide numbers 57 to 1541 in the nucleotide sequence shown in SEQ ID NO: 1 in the sequence listing, or under stringent conditions And a DNA encoding a polypeptide having a base sequence capable of hybridizing with the above and having the same catalase activity as the sequence. As used herein, “stringent conditions” means that only a base sequence encoding a polypeptide having catalase activity equivalent to that of catalase encoded by a specific catalase gene sequence forms a hybrid with the specific sequence (so-called specific hybrid). However, a base sequence encoding a polypeptide having no equivalent activity means a condition that does not form a hybrid (so-called non-specific hybrid) with the specific sequence. Those skilled in the art can easily select such conditions by changing the temperature during the hybridization reaction and the washing, and the salt concentration of the hybridization reaction solution and the washing solution. Specifically, 6 × SSC (0.9M N
aCl, 0.09M trisodium citrate) or 6
× SSPE (3M NaCl, 0.2M NaH ₂ PO
₄ , 42 mM in 20 mM EDTA · 2Na, pH 7.4)
At 0.5 ° C and at 42 ° C for 0.5 x SS.
Conditions for washing with C are mentioned as one example of the stringent conditions of the present invention, but are not limited thereto.

The “base sequence capable of hybridizing under stringent conditions” of the present invention refers to the nucleotide sequence of SEQ ID NO: 1 for an arbitrary DNA pool (for example, a cDNA or genomic DNA library derived from catalase-producing cells or tissues). It can be obtained by performing a hybridization reaction under stringent conditions using DNA having a sequence as a probe.

The term "exogenous" means that the cotton plant does not naturally exist and is introduced from outside. Therefore, the "exogenous catalase gene" of the present invention
May be a catalase gene of the same species as the host cotton plant (that is, derived from the host cotton plant), which is externally introduced by genetic manipulation. Codon usage (codon usag
Given the identity of e), the use of a host-derived catalase gene is also preferred.

The exogenous catalase gene may be introduced into the cotton plant by any genetic engineering technique, for example, protoplast fusion with a heterologous plant cell having the catalase gene, a virus genome genetically engineered to express the catalase gene Or the transformation of host cotton plant cells with an expression vector containing the catalase gene.

However, preferably, the cotton plant of the present invention is an expression vector containing an exogenous catalase gene under the control of a promoter capable of functioning in cotton fiber,
It is a transgenic plant obtained by transforming cells of a cotton plant wild strain.

Examples of the promoter that can function in cotton fiber include a promoter of a gene constitutively expressed in a plant cell, preferably a constitutive promoter derived from a plant or a plant virus (for example, a cauliflower mosaic virus (CaMV) 35S promoter, a CaMV19S promoter). Promoter, NOS promoter, etc.), and a cotton plant-specific promoter that is specifically expressed during the formation and elongation of cotton fibers. Examples of such a cotton fiber-specific promoter include various promoters described in International Publication WO95 / 08914.

In the expression vector of the present invention, the exogenous catalase gene is placed downstream of the promoter so that its transcription is controlled by a promoter capable of functioning in cotton fiber. Downstream of the catalase gene,
It is preferable that a transcription termination signal (terminator region) that can function in the cotton fiber is further added. Examples of such a terminator include a NOS (nopaline synthase) gene terminator.

Since the elongation of the cotton fiber involves the development of the cell wall, it is expected that the genes involved in fiber elongation preferably exhibit activity in and near the cell wall. Therefore, if the exogenous catalase gene to be introduced does not have a coding sequence for a cell wall translocation signal recognized in cotton plant cells, insert the coding sequence for the signal peptide between the promoter and the coding sequence for mature catalase. It is desirable to do. As such a signal sequence, a signal sequence of peroxidase derived from cotton plant and the like are preferably exemplified.

[0032] The expression vector of the present invention may further contain a cis-regulatory element such as an enhancer sequence.
The expression vector may be a marker gene for selecting a transformant such as a drug resistance gene marker, for example, neomycin phosphotransferase II (NPTII) gene, phosphinothricin acetyltransferase (PAT) gene, glyphosate resistance gene, etc. It is desirable to further include Under conditions where no selective pressure is applied,
Since a phenomenon in which the integrated gene is dropped may occur, if the herbicide-tolerant gene is allowed to coexist on the vector, the conditions under which the selection pressure is always applied can be realized by using the herbicide during cultivation. There is also an advantage. Furthermore, in order to facilitate large-scale preparation and purification, the expression vector should contain an origin of replication that enables autonomous replication in E. coli and a selectable marker gene in E. coli (eg, ampicillin resistance gene, tetracycline resistance gene, etc.). Is desirable. The expression vector of the present invention is simply
It can be constructed by inserting an expression cassette for the catalase gene and, if necessary, a selectable marker gene into a cloning site of a pUC or pBR Escherichia coli vector.

When an exogenous catalase gene is introduced by using Agrobacterium tumefaciens or Agrobacterium rhizogenes infection, Ti or Ri carried by the bacterium is used. T on plasmid
-An expression cassette for the catalase gene can be used by inserting it into a DNA region (region that transfers to a plant chromosome). At present, the standard method of Agrobacterium-mediated transformation uses a binary vector system. T
-The functions required for DNA transfer are T-DNA itself and Ti-DNA.
(Or Ri) supplied independently from both plasmids,
Each component can be split on a separate vector.
The binary plasmid has a 25 bp border sequence at both ends necessary for excision and integration of T-DNA, and the plant hormone gene causing crown gall (or hairy root) has been removed, while at the same time providing room for insertion of a foreign gene. ing. Examples of such a binary vector include pBI101 and pBI121 (both CLONTECH)
Are commercially available. The vir region acting on the integration of T-DNA is located on another Ti (or Ri) plasmid called a helper plasmid and acts on trans.

For the transformation of cotton plants, various conventionally known methods can be used. For example, protoplasts are isolated from cotton plant cells by treatment with a cell wall degrading enzyme such as cellulase or hemicellulase, and polyethylene glycol is added to a suspension of the protoplasts and an expression vector containing the catalase gene expression cassette to add endoglycol. A method in which the expression vector is incorporated into protoplasts in the process of toosis (PEG method), an expression vector is put into lipid membrane vesicles such as phosphatidylcholine by ultrasonic treatment or the like, and the vesicles and protoplasts are fused in the presence of PEG. Liposome method, fusion using minicells in the same process, application of an electric pulse to the suspension of protoplast and expression vector to incorporate the vector in the external solution into the protoplast (electroporation). Method). However,
These methods are complicated in that they require a culture technique for redifferentiating protoplasts into plants. As a means for introducing a gene into an intact cell having a cell wall, a micropipette is pierced into the cell, and a vector DNA in the pipette is injected into the cell by hydraulic pressure or gas pressure. A direct introduction method such as a particle gun method, which accelerates the explosive using explosives or gas pressure and introduces it into cells.
There is a method using infection by Agrobacterium. Microinjection requires skill in operation, and has the drawback that the number of cells that can be handled is small. Therefore, in consideration of the simplicity of the operation, it is preferable to transform the cotton plant by the Agrobacterium method and the particle gun method. The particle gun method is further useful in that a gene can be directly introduced into the apical meristem of a growing plant. In addition, in the Agrobacterium method, a genomic DNA of a plant virus, for example, a geminivirus such as tomato golden mosaic virus (TGMV) is simultaneously inserted into a binary vector between border sequences, so that an arbitrary site of a cultivated plant can be obtained. Simply inoculating the cells with the bacterial suspension using a syringe or the like spreads the virus infection throughout the plant, and simultaneously introduces the target gene into the whole plant.

However, in the particle gun method and the Agrobacterium method, gene transfer is often chimeric, so that a sample cell in which the catalase gene is frequently introduced into germ line cells is used. Must be used for transformation. Examples include embryos, hypocotyl sections, embryogenic callus, isolated growth points, and the like. On the other hand, each of the above-described transformation methods and microinjection methods using protoplasts allows selection of a regenerated plant from a single cell, so that a homogeneous transgenic plant having a catalase gene introduced into all cells is obtained. From a viewpoint, it can be said that it is an excellent transformation means.

Hereinafter, as a specific example, a method for introducing a target gene into cotton plants by Agrobacterium and regenerating transformed cells into plants will be described. The seeds of the cotton plants are transferred to Stewart's seed germination medium (Stewar
t, 0.75 g / L MgCl ₂ , 2.0 g / L
L Fightagel, pH 6.8) and aseptically cultivated. On the other hand, Agrobacterium transformed with a plasmid having the kanamycin resistance gene and the target gene connected to the promoter was cultured, and MSN was cultured.
H (MS inorganic salts, 30 g / L glucose, pH 5.
Dispense the solution diluted in 8) into tubes. Hypocotyls are cut out from the germinated cotton seedlings, and hypocotyl sections are immersed in the above-mentioned diluent of bacteria to infect. The hypocotyl section infected with Agrobacterium was removed from the sterilized filter paper, and the Agrobacterium diluted solution was removed therefrom. T2 plate (MS inorganic salts, 0.75 g / L MgCl ₂ , 0.1 mg / L)
2,4-D, 0.5 mg / L Kinetin, 30 g / L
Glucose, 2.0 g / L Fightagel, pH
5.8) and co-culture for 3 days. Co-cultured hypocotyls were plated on MS2NKKKCL plates (MS inorganic salts, 0.75 g
/ L MgCl ₂ , 30 g / L glucose, 2 mg / L
L naphthalene acetic acid, 0.1 mg / L kinetin,
2.0 g / L fightagel, 50 μg / ml kanamycin, 500 μg / ml cefotaxime, pH
5.8) Transfer to above and perform callus culture for 3-4 weeks. About 4
When calli of mm size are observed, the calli are removed from the hypocotyl and transferred to a fresh MS2NKKKCL plate for further growth. After sufficient growth to a callus of about 1 cm in size, the cells are transferred to a kanamycin-containing MSNH liquid medium for embryo induction, and liquid suspension culture is started. The liquid suspension culture is performed until slightly spherical and light green cells can be visually observed. The suspension culture containing the fully grown cells was diluted with MKNH and diluted with MSK50K plate (MS inorganic salts, 0.75 g / L MgCl ₂ , 1.9 g / LK).
NO ₃ , 30 g / L glucose, 2.0 g / L phytogel, 50 μg / ml kanamycin, pH5.
Transfer to 8), spread on a plate and perform embryo formation. The culture was continued until embryos of at least about 1 mm in size were formed, and a germination medium, an SA plate (Stewart concentrate, 20 g) was used.
/ L sucrose, 20 g / L agar, pH 6.8). After culturing for several weeks and rooting was observed, the roots were removed and the embryos were plated on an SGA plate (Stewart concentrate, 5 g / L).
Sucrose, 0.75 g / L MgCl ₂ , 5 g / L
Agar, 1.5 g / L fighter gel, pH 6.8)
And culture is continued until true leaves are observed. Once the first true leaves have been observed, the cotton seedlings can be transplanted into pint-sized canned bottles containing SGA medium.
When the height of the cotton seedlings becomes 10 cm and several true leaves are observed, they can be planted in appropriate pots and cultivated in a greenhouse. Seeds and cotton fibers can be obtained from the thus obtained cotton transformant.

From this transformant, genomic DNA was extracted according to a conventional method, this DNA was cut with an appropriate restriction enzyme, and Southern hybridization was carried out using the introduced target gene as a probe to confirm the presence or absence of the transformation. can do. Alternatively, a primer for specifically amplifying the target gene can be synthesized, and the presence or absence of transformation can be confirmed by PCR. In addition, RNA is extracted from a transformant or a non-transformant according to a conventional method, a probe having a sense or antisense sequence of the introduced target gene is prepared, and Northern hybridization is performed using these probes. The state of expression of the target gene can be examined.

[0038] Cotton fibers differentiated from seeds obtained by self-pollination of the transgenic cotton plant thus obtained include those having improved fiber characteristics as compared to cotton fibers obtained from wild strains, exogenous catalase. It is included at a statistically constant ratio depending on the mode of gene integration. Preferably, the cotton fiber has at least one parameter of fiber fineness or fiber length uniformity, more preferably
Both parameters have improved fiber properties. More preferably, the cotton fiber has a fiber property in which the fiber length and fiber strength are further improved as compared with the wild type.

The appearance ratio of the improved fiber characteristics in cotton fibers differentiated from R1 seeds obtained by self-pollination of the regenerated modern (R0) plant usually follows Mendel's rule. For example, if the catalase gene is heterozygously integrated at one locus, the improved cotton fiber properties segregate at a 3: 1 ratio in R1 seed. In the R2 seed obtained by cultivating and self-pollinating R1 seed differentiated cotton fiber having improved fiber properties,
If the improved cotton fiber properties are retained in all seeds, the R1 plant is homozygote for the introduced catalase gene and, if the cotton fiber properties are separated 3: 1, The R1 plant can be determined to be heterozygote for the introduced catalase gene.

The cotton plant thus selected, which is homozygous for the introduced catalase gene,
As a fixed line with improved cotton fiber properties, it is very useful in the field of seed industry.

The present invention also provides a method for producing cotton fibers from cotton plants producing cotton fibers having improved fiber properties obtained as described above. Using the cotton seeds of the selected line, a cultivation test can be performed in a closed system greenhouse or an isolated field. In the cultivation test, the selected cotton seeds are sown in accordance with a conventional method, the cotton plants are grown and flowered, and then self-pollinated to obtain berries, and the seeds can be collected from the berries.

By subjecting the collected seeds to machine ginning according to a conventional method, cotton fibers can be isolated. With respect to the obtained cotton fiber, the properties of the cotton fiber can be evaluated using, for example, a sorter method, a Presley method, a sterometer method, an HVI (mass high-speed inspection machine) system method, or the like.

[0043]

The present invention will be described in more detail with reference to the following examples, which are merely illustrative and do not limit the scope of the present invention.

Reference Example 1 Catalase cDN from pea
Isolation of A cDNA cloning was performed using Plant Mol. Biol., 17, 1263.
-1265 (1991), page 1263, left column, line 18 to right column, line 15; (1) Construction of cDNA Library Leaves were collected from the seedlings of pea (Pisum sativum) on the 10th day of germination, and poly (A) ⁺ RNA was extracted according to a conventional method. Using the isolated poly (A) ⁺ RNA as a template, oligo (dT) primer and reverse transcriptase
DNA was synthesized, double-stranded by a polymerase reaction, inserted into a vector, and transformed into Escherichia coli to prepare a cDNA library. poly
(A) ⁺ RNA isolation and cDNA synthesis were performed using commercially available cD
This was performed using an NA cloning kit according to the attached protocol.

(2) Screening of target gene by plaque hybridization method A catalase gene (Ni W., Turley RB, Trelease R.) derived from a cotton plant was applied to a filter replicating a phage plaque of the cDNA library prepared by the above method.
N., Biochim. Biophys. Acta., 1049, 219-222 (199
0)) The cDNA was hybridized with a probe labeled with ³² P, which is a radioisotope, as a probe, and a positive signal was detected.
Was selected. The nucleotide sequence of the cloned cDNA was determined by the dideoxy method using an automatic sequencer. The obtained base sequence is shown in SEQ ID NO: 1 in the Sequence Listing. ORF encoding 494 amino acids (base number 57
~ 1541). This pea-derived catalase gene was named CAT.

Example 1 Preparation of Transformant of Cotton Plant (1) Construction of Catalase Gene Expression Plasmid CaMV35S promoter and CA shown in SEQ ID NO: 1
The cell wall translocation signal sequence of cotton plant-derived peroxidase was inserted between the T gene. FIG. 1 shows the procedure for vector construction. The signal sequence (SS) was amplified from a cotton library derived from a cotton plant by PCR using specific primers to which XhoI and BamHI restriction enzyme sites were added according to a conventional method, and subcloned into a pRTL2 vector. Next, the CAT gene was transformed with BamHI and H
fragment 1 (Fr. 1) digested with indIII, H
Fragment 2 (F) digested with indIII and EcoRI
r. 2) The fragment was divided into fragment 3 (Fr. 3) digested with EcoRI and XbaI. Fragment 1 was ligated to the signal sequence and fragment 2 was ligated. Fragment 3 contains the 35S promoter sequence (35Spro) and the terminator sequence (te
r). The fragment in which the signal sequence was ligated to fragments 1 and 2 was digested with XhoI and EcoRI,
It was subcloned between the 5S promoter and fragment 3. Next, this clone was cut with PstI,
Expression cassette (Nos pro-npt) for kanamycin resistance gene (nptII) using amHI adapter
II-ter) into the binary vector pBIN19. This plasmid is called pBIN35
SS. It was named S-CAT. In addition, Escherichia coli JM109 transformed with the plasmid was used to transform Escherichia coli JM109 / pBIN35S-
S. It was named S-CAT.

(2) Introduction of plasmid into Agrobacterium Escherichia coli JM109 /
pBIN35S-S. Escherichia coli HB101 carrying S-CAT and helper plasmid pRK2013
And LB each containing 50 μg / ml kanamycin.
In a medium at 37 ° C. overnight, and also with Agrobacterium EHA
The 101 strains were cultured in an LB medium containing 50 μg / ml kanamycin at 37 ° C. for 2 nights. 1.5 ml of each culture was taken into an Eppendorf tube, centrifuged to collect the cells, and then washed with LB medium. After suspending these cells in 1 ml of LB medium,
100 μl of each suspension was placed in another tube, and the three bacteria were mixed, spread on an LB agar medium, cultured at 28 ° C., and conjugated to transfer the two plasmids to Agrobacterium. After 1-2 days, a part of the colony is scraped with a platinum loop.
The cells were spread on an LB agar medium containing 50 μg / ml kanamycin. After culturing at 28 ° C. for 2 days, single colonies were selected. The obtained transformant was transformed into EHA101 / pBIN3
5S-S. It was named S-CAT.

(3) Sterilization and Germination of Seed Cotton Plant (G. Hirstum cultivar Culker 312)
Seeds were left in 70% ethanol for 30 seconds. Seeds were collected and washed with 100 ml of sterile water. Subsequently, it was immersed in a sterilizing solution (Clorox / Tween 20) and shaken (110 rpm) for 20 minutes. Collect seeds, 100m
After washing with 1 liter of sterile water, the seeds were thoroughly washed with sterile water for about 30-60 minutes. The sterilized seeds are plated on a seed germination medium plate (Stewart concentrate, 0.75 g / L MgCl
₂ , 2.0 g / L Fightagel, pH 6.8). This plate was cultured at 30 ° C. for 7 to 10 days.

(4) Infection with Agrobacterium The cotton seedling obtained in (3) was taken out, the cotyledon and the root were removed with a scalpel, and a hypocotyl of 6 to 8 mm in size was cut out.
The transformed Agrobacterium obtained in the above (2) is cultured at 30 ° C. for 24 hours, and the culture solution is washed with MSNH (MS inorganic salts, 30 g / L glucose, pH 5.8) for 19 hours.
It was diluted twice. Hypocotyl sections were immersed in the diluted culture solution for 30 seconds. Hypocotyls are arranged on two stacked sterilized filter papers, and excess water is removed. T2 plates (MS inorganic salts, 0.75 g / L)
MgCl ₂ , 0.1 mg / L 2,4-D, 0.5 mg
/ L kinetin, 30g / L glucose, 2.0g
/ L Fightagel, pH 5.8). T
The two plates were co-cultured in the dark at room temperature for 3 days. Co-cultured hypocotyls were plated on MS2NKKKCL plates (MS inorganic salts, 0.75 g / L MgCl ₂ , 30 g / L glucose, 2 mg / L naphthalene acetic acid, 0.1 mg / L kinetin, 2.0 g / L fightagel, 50 μg /
ml kanamycin, 500 μg / ml cefotaxime, pH 5.8), sealed with parafilm to prevent drying, and cultured at 30 ° C. under light conditions.

(5) Callus formation Hypocotyls were cultured on MS2NKKKCL plates and transferred to a new plate every month. About 3 transformed calli
Appeared after ~ 4 weeks. Culture to a callus of about 4 mm in size, cut out from the hypocotyl with a scalpel and use fresh MS2NK
Transferred to KCL plate. The cells were grown sufficiently (required for 3 to 5 months) until the calli became about 1 cm in size.

(6) Embryogenesis A well-grown callus was transformed with kanamycin (250 μg / ml).
Was transferred to a 50 ml-size culture flask containing 10 ml of an MSNH liquid medium containing, and liquid suspension culture was performed. The liquid suspension culture was performed by shaking at 30 ° C. (110 r.
pm) by culture for about 2-8 weeks. After spherical and light green cells were observed in the culture, the culture was transferred to a 50 ml sterile tube, and the cells were collected at the bottom of the tube. The supernatant MSNH liquid medium was removed and cells were washed by adding about 20-30 ml of fresh MSNH liquid medium. This operation was performed twice. Cells are collected at the bottom of the tube and 9.5 m for 0.5 ml cells
l of MSNH liquid medium was added to prepare a cell diluent. The cell diluent was collected in 2 ml portions, and each was placed on an MSK50 plate (MS inorganic salts, 0.75 g / L MgCl ₂ , 1.9).
g / L KNO ₃ , 30 g / L glucose, 2.0 g
/ L Fightagel, 50 μg / ml kanamycin, pH 5.8) and spread evenly on the plate. Plates were sealed with parafilm to prevent drying and incubated at 30 ° C under light conditions. When the state of development of the somatic embryo was confirmed, some somatic embryos were observed on the plate after about 3 weeks. The emerged somatic embryos are developed to at least 1 mm size, and are plated on SA plate (Stewart concentrate, 20 g / L sucrose, 20 g).
/ L agar, pH 6.8).

(7) Regeneration of Transformed Plant Seal the SA plate with Parafilm,
Incubated at about 2 weeks. Two weeks later, the roots were cut off with a scalpel and the embryos were plated on SGA plates (Stewart concentrate, 5 g / L sucrose, 0.75 g / L MgCl 2).
₂ , 5 g / L agar, 1.5 g / L fighter gel,
pH 6.8). The SGA plate was incubated at 30 ° C. under light conditions without sealing with parafilm. Germinated embryos were incubated on SGA plates until the emergence of true leaves. The young plant in which true leaves were observed was transplanted to a pint-sized canned bottle. Transformants having a height of about 10 cm and several true leaves were transferred to pots and grown in a greenhouse. Southern hybridization and Northern hybridization analysis were performed on the regenerated transformant and the R1 plant grown from the R1 seed obtained from the transformant, and the target catalase gene was stably integrated and expressed. Transformants were identified.

Example 2 Field test of transformant (1) Line into which target gene has been introduced (cell line)
Selection of the transformants prepared in Example 1
Cultivation tests were performed in a closed greenhouse attached to Texas Tech University over 997, and the introduction of the target gene was confirmed by Northern analysis, and the characteristics of the obtained cotton fibers were evaluated. From the results, cell lines into which the target catalase gene was reliably introduced and which expressed the gene were selected (Table 1).

[0054]

[Table 1]

(2) Cultivation test in isolated field (conducted from May to December 1998) Seeds of cell lines shown in Table 1 and coker 312 which had not been genetically modified were used as test materials. 19
The seeds were sown on an isolated field attached to Texas Tech University on May 20, 1998. From July 5, 1998, these cotton plants began to flower and self-pollinated. Healthy young leaves were collected from all the transformants cultivated from July to September 1998, and Northern analysis was performed using the introduced target gene as a probe according to a conventional method to examine the expression of the target gene. From September 1998, the fruits were opened and dried, and the ovules were harvested. Texas A & M Agricultural Exper
Machine ginning was performed at the iment Station to separate the cotton fibers from the seeds. About the obtained cotton fiber, (1) 9
Using a 00HVI system (Spinlab),
Fiber fineness, fiber length uniformity, fiber length and fiber strength were measured. Table 2 shows the results.

[0056]

[Table 2]

As is clear from Table 2, the transformants in which CAT, a catalase gene derived from pea, was introduced, showed remarkable increases in fiber fineness, fiber length uniformity and fiber strength in all cell lines. From the above results, it can be seen that by introducing CAT, a catalase gene derived from pea, into a cotton plant, a cotton plant producing a cotton fiber with significantly increased fiber properties such as fiber fineness and fiber length uniformity can be obtained. It became clear.

[0058]

As described above, according to the present invention, it is possible to improve the fiber properties of the cotton fiber, such as the fineness and the uniformity of the fiber length. For example, the improved fineness improves the dyeability of the yarn. Further, by improving the fiber length uniformity, the strength of the yarn is increased. Therefore, the quality of the woven fabric can be improved by the cotton fiber collected from the cotton plant of the present invention. Further, the cotton plant of the present invention has better cotton fiber properties and / or cotton fiber productivity,
Further, it can be used as a plant material for producing a new cotton variety.

[0059]

[Sequence List] SEQUENCE LISTING <110> Toyo Boseki Kabushiki Kaisha <120> Cotton Plant Having Improved Cotton Fiber Properties, Process for Producing Thereof and Process for Producing Cotton Fiber Therefrom <130> A-4017 <160> 1 <210> 1 < 211> 1738 <212> DNA <213> Pisum sativum <220> <221> CDS <222> (57) ... (1541) <400> 1 attttctcta atccctatct tctgctccac caccaccgtc tatcgcttcc atttcc atg 59 Met 1 gat cct tac aag cat cgt cct tct agc gct ttc aat tct cct ttc tgg 107 Asp Pro Tyr Lys His Arg Pro Ser Ser Ala Phe Asn Ser Pro Phe Trp 5 10 15 act acg aac tcc ggt gct cct gtt tgg aat aat aac tct tcc cta acc 155 Thr Thr Asn Ser Gly Ala Pro Val Trp Asn Asn Asn Ser Ser Leu Thr 20 25 30 gtt gga tct aga ggt cca att cta ttg gaa gat tat cat ctt gtg gaa 203 Val Gly Set Arg Gly Pro Ile Leu Leu Glu Asp Tyr His Let Val Glu 35 40 45 aag ctt gcc caa ttt gat agg gaa agg atc cca gaa cgt gtt gtc cat 251 Lys Leu Ala Gln Phe Asp Arg Glu Arg Ile Pro Glu Arg Val Val His 50 55 60 65 gct agg gga gca agt gca aag ggt ttc t tt gaa gtc aca cat gat att 299 Ala Arg Gly Ala Ser Ala Lys Gly Phe Phe Glu Val Thr His Asp Ile 70 75 80 tcg cac ctg aca tgt gca gat ttc ctt cga gcc cct ggt gtt cag aca 347 Ser His Leu Thr Cys Ala Asp Phe Leu Arg Ala Pro Gly Val Gln Thr 85 90 95 cct gtc att gtg cgt ttc tca act gtc att cat gaa cgt ggc agc cct 395 Pro Val Ile Val Arg Phe Ser Thr Val Ile His Glu Arg Gly Ser Pro 100 105 110 gaa acc ttg agg gat ccc cga ggt ttt gct gtg aaa ttt tac acc aga 443 Glu Thr Leu Arg Asp Pro Arg Gly Phe Ala Val Lys Phe Tyr Thr Arg 115 120 125 gag ggt aac tat gac ctt gtt gga aac aac ttt ccc gtc ttc ttc gtt 491 Glu Gly Asn Tyr Asp Leu Val Gly Asn Asn Phe Pro Val Phe Phe Val 130 135 140 145 cat gac ggt atg aat ttt cca gat atg gtc cat gct ctt aaa ccc aat 539 His Asp Gly Met Asn Phe Pro Asp Met Val His Ala Leu Lys Pro Asn 150 155 160 ccc cag acc cac atc cag gag aat tgg aga att ctt gat ttc ttc tac 587 Pro Gln Thr His Ile Gln Glu Asn Trp Arg Ile Leu Asp Phe Phe Tyr 165 170 175 aac ttt cca gaa agc ctt cac atg ttc tcc ttc cta ttt gat gat gtg 635 Asn Phe Pro Glu Ser Leu His Met Phe Ser Phe Leu Phe Asp Asp Val 180 185 190 ggt gtc cca caa gat tat agg cat atg gat ggt ttt gga gtt aac aca 683 Gly Val Pro Gln Asp Tyr Arg His Met Asp Gly Phe Gly Val Asn Thr 195 200 205 tac acc ctg atc aac aag gct gga aaa tcg gtg tat gtc aaa ttt cac 731 Tyr Thr Leu Ile Asn Lys Ala Gly Lys Ser Val Tyr Val Lys Phe His 210 215 220 225 tgg aag ccc acc tgt ggt gtg aag tgt cta ttg gag gaa gag gcc att 779 Trp Lys Pro Thr Cys Gly Val Lys Cys Leu Leu Glu Glu Glu Ala Ile 230 235 240 cag gtg gga gga tcc aac cac agc cat gct act aaa gac ctt tat gac 827 Gln Val Gly Gly Ser Asn His Ser His Ala Thr Lys Asp Leu Tyr Asp 245 250 255 tca att gct gct ggt aac tat cct gag tgg aaa ctt tac att caa aca 875 Ser Ile Ala Ala Gly Asn Tyr Pro Glu Trp Lys Leu Tyr Ile Gln Thr 260 265 270 ata gat cct gct cat gaa gac aga ttt gag ttt gac cca ctt gat gta 923 Ile Asp Pro Ala His GLu Asp Arg Phe Glu Phe Asp Pro Leu Asp Val 275 280 285 285 act aag act tgg cc c gag gac atc ata ccc ctt cag ccc gta ggt cgc 971 Thr Lys Thr Trp Pro Glu Asp Ile Ile Peo Leu Gln Pro Val Gly Arg 290 295 300 305 atg gtc ttg aac aag aac ata gat aat ttc ttt gct gag aat gaa cag 10 Met Val Leu Asn Lys Asn Ile Asp Asn Phe Phe Ala Glu Asn Glu Gln 310 315 320 ctt gca ttt tgt cct gcc att atg ctg cct ggt ata tat tac tca gat 1067 Leu Ala Phe Cys Pro Ala Ile Met Leu Pro Gly Ile Tyr Tyr Ser Asp 325 330 335 gac aag atg ctt caa act agg gtt ttc tct tat gct gat tca cag agg 1115 Asp Lys Met Leu Gln Thr Arg Val Phe Ser Tyr Ala Asp Ser Gln Arg 340 345 350 cac aga ctt gga ccg aac tac ctg caa ctt cct gtt aat gct ccc aag 1163 His Arg Leu Gly Pro Asn Tyr Leu Gln Leu Pro Val Asn Ala Pro Lys 355 360 365 tgg tct cac cac aac aat cac cat gag ggt ttc atg aat gcc att cac 1211 Trp Ser His His Asn Asn His His Glu Gly Phe Met Asn Ala Ile His 370 375 380 385 agg gat gag gag gtc aat tac ttc cct tca agg cat gat act gtt cgt 1259 Arg Asp Glu Glu Val Asn Tyr Phe Pro Ser Arg His Asp Thr Val Arg 390 395 400 cat gca gaa agg gtc ccc att cct act act cat tta tct gca agg cgt 1307 HIs Ala Glu Arg Val Pro Ile Pro Thr Thr His leu Ser Ala Arg Arg 405 410 415 gaa aag tgc aat att ccg aaa cag aat cac ttc aag cag gct gca gaa 1355 Glu Lys Cys Asn Ile Pro Lys Gln Asn His Phe Lys Gln Ala Gly Glu 420 425 430 aga tac cga act tgg gca cct gac agg cag gaa aga ttt ctc cgc agg 1403 Arg Tyr Arg Thr Trp Ala Pro Asp Arg Gln Glu Arg Phe Leu Arg Arg 435 440 445 tgg gta gaa gct tta tcc gac acc gat cca cgc atc acc cat gaa atc 1451 Trp Val Glu Ala leu Ser Asp Thr Asp Pro Arg Ile Thr HIs Glu Ile 450 455 460 465 cgc agc attgg gta tca tac tgg tct cag gct gat cgt tct ctt ggg 1499 Arg Ser Ile Trp Val Ser Tyr Trp Ser Gln Ala Asp Arg Ser Leu Gly 470 475 480 cag aag tta gca tct cat ctg aac atg agg cct agc att taactttgtt 1548 Gln Lys Ala Ser His Leu Asn Met Arg Pro Ser Ile 485 490 gccaaatatt gaatcatcgc aagatttgca gatgtgcaaa atgtatgata aaggatgttt 1608 gtttggatta cttgaaaaga ctttttattt ttgttataat tttatatcgt gaatgtatac 16 68 cataaattct atgtatgcaa cttgttgaga tgttacaata aatccgtagg catgtgttag 1728 tgttaaaaaa 1738

[Brief description of the drawings]

FIG. 1 shows a binary vector pBIN35S-S.S. Containing an expression cassette for a catalase gene derived from pea. SC
FIG. 3 is a diagram showing an AT construction procedure. The meanings of the abbreviations in the figure are as follows. S. S: Cotton peroxidase-derived cell wall translocation signal sequence, Fr. 1: Fragment 1, Fr. 2: Fragment 2, Fr. 3: Fragment 3, 35S pro: cauliflower mosaic virus-derived 35S promoter, ter: terminator, N
OS pro: nopaline synthase promoter, npt
II: neomycin phosphotransferase II coding sequence; S-CAT: Fusion gene of cotton peroxidase-derived cell wall translocation signal sequence and pea-derived catalase cDNA, RB: Right border sequence, LB: Left border sequence, Xh: XhoI restriction site, B: Bam
HI restriction site, H: HindIII restriction site, E: E
coRI restriction site, Xb: XbaI restriction site, P:
PstI restriction site

Continued on the front page (72) Inventor Izumi Inohara 2-1-1 Katata, Otsu-shi, Shiga Prefecture Inside Toyobo Co., Ltd. Research Institute (72) Inventor Norihiko Maekawa 2-1-1 Katata, Otsu-shi, Shiga Toyobo Co., Ltd. In-house Research Institute (72) Inventor Randy Allen 3104, Forties Street, Love Box, Texas, USA F term (reference) 2B030 AA02 AA03 AB03 AD08 CA17 CA19 CB02 CD03 CD07 CD10 CD13 CD17 CD21 4B024 AA08 BA08 CA04 DA01 EA04 FA02 FA07 FA10 FA18 GA11 GA17 4B050 CC03 DD09 LL10 4B065 AA88Y AA89X AB01 AC14 BA02 CA28 CA53

Claims (17)

[Claims] 1. An exogenous catalase gene under the control of a promoter capable of functioning in cotton fiber is stably retained,
A cotton plant belonging to the genus Gossypium, which produces cotton fibers having improved fiber characteristics as compared to wild strains. 2. The cotton plant is a transgenic plant obtained by transforming the wild type strain with an expression vector containing an exogenous catalase gene under the control of a promoter capable of functioning in cotton fiber. The cotton plant according to 1. 3. The catalase gene is derived from a plant,
The cotton plant according to claim 1. 4. The cotton plant according to claim 3, wherein said catalase gene is derived from pea. 5. The cotton plant according to claim 1, wherein the catalase gene has the following nucleotide sequence (a) or (b). (A) a base sequence represented by base numbers 57 to 1541 in the base sequence shown in SEQ ID NO: 1 of the Sequence Listing (b) a base sequence capable of hybridizing with the base sequence of the above (a) under stringent conditions 6. The cotton plant according to claim 1, wherein said cotton plant is Gossypium hirsutum, Gossypium barbadense, Gossypium arboreum, Gossypium anomalum, Gossypium almurianum, Gossypium clotzchianum, Gossypium.
The cotton plant according to any one of claims 1 to 5, wherein the cotton plant is derived from a plant selected from the group consisting of Herbaqueum and Gossypium lemonday. 7. The cotton plant according to claim 1, which is homozygous for the catalase gene. 8. The cotton plant according to claim 7, which is in the form of a seed. 9. A cotton fiber obtained from the cotton plant according to any one of claims 1 to 7 having improved fiber properties compared to a wild strain. 10. A method for transforming a cell of a wild plant of the genus Gossypium with an expression vector containing an exogenous catalase gene under the control of a promoter capable of functioning in a cotton fiber. A method for producing a cotton plant that produces cotton fibers having improved fiber properties. 11. The method according to claim 10, further comprising a step of regenerating a plant from the transformed cell. 12. The method according to claim 10, wherein the catalase gene is derived from a plant. 13. The method according to claim 12, wherein said catalase gene is derived from pea. 14. The catalase gene according to the following (a):
Or having the base sequence of (b).
12. The method according to 0 or 11. (A) a base sequence represented by base numbers 57 to 1541 in the base sequence shown in SEQ ID NO: 1 of the Sequence Listing (b) a base sequence capable of hybridizing with the base sequence of the above (a) under stringent conditions 15. The cotton plant wild strain is selected from the group consisting of Gossypium hirsutum, Gossypium barbadense, Gossypium arboreum, Gossypium anomalum, Gossypium almurianum, Gossypium clotzchianum, Gossypium herbaqueum, and Gossypium lemonday. The method according to claim 10, wherein the method is performed. 16. The following steps: (1) transforming a cell of a wild plant of cotton belonging to the genus Gossypium with an expression vector containing an exogenous catalase gene under the control of a promoter capable of functioning in cotton fiber;
(2) a cotton plant (R0) that produces, from the transformed cell, a cotton fiber having improved fiber properties as compared to a wild strain
(3) self-pollination of the seed from the plant, and (4) isolation of the catalase gene in the seed obtained by self-pollination from a cotton plant (R1) obtained by cultivating the seed. A method for producing a cotton plant in which a trait for producing a cotton fiber that is homozygous for the catalase gene and has improved fiber properties compared to the wild type is fixed, which comprises assaying a ratio. 17. An improved method as compared to a wild strain, comprising a step of collecting a seed obtained by self-pollinating the cotton plant according to any one of claims 1 to 7, and separating a cotton fiber from a seed coat of the seed. For producing cotton fibers having improved fiber properties.