Application of AgKATA gene in optimization of cotton fiber quality

Abstract

The invention discloses application of an AgKATA gene in optimization of cotton fiber quality, and belongs to the technical field of genetic engineering. According to the invention, the expression of AgKATA is controlled by using a promoter E6 specifically expressed by fibers, a transgenic cotton strain is obtained by using an agrobacterium transformation method, when identification and analysis are carried out on transgenic cotton T0-generation plants with pE6 excess AgKATA, it is found that excess exogenous AgKATA genes can reduce the content of hydrogen peroxide in cotton fiber cells, and after mature fibers are observed, it is found that the content of hydrogen peroxide in cotton fiber cells can be reduced. The mature fiber length of the E6-KATA-1 single plant with a higher transcriptional level is longer than that of the E6-KATA-18 single plant with a lower transcriptional level, and the cell wall of the E6-KATA-1 single plant is obviously thinned.

Description

Technical Field

[0001] The present invention belongs to the field of genetic engineering technology and specifically relates to a AgKATA Application of genes in optimizing cotton fiber quality. Background Art

[0002] Cotton is an annual or perennial subshrub or small tree belonging to the Dicotyledoneae, Malvales, Malvacese, and Gossypium. Currently, there are four cotton cultivars with economic value in the world: two diploid cottons (African cotton and Asian cotton) and two allotetraploid cottons (Upland cotton and Sea island cotton). Upland cotton has high yield and strong adaptability, and is the most widely used cotton variety.

[0003] The intrinsic quality indicators of cotton fiber mainly include four key indicators: fiber length, fiber fineness, fiber strength and fiber maturity. The problems faced by cotton production in my country are short fiber length, low strength and coarse fiber, which are far from meeting the needs of the market. Therefore, increasing cotton fiber yield and improving fiber quality are important goals of cotton breeding in China. Traditional genetic breeding methods have a long cycle and a large workload. In addition, the yield and quality of cotton fiber are quantitative traits, which have a strong negative correlation in genetics and are easily affected by many factors. Therefore, it is difficult to improve cotton quality quickly and efficiently by relying solely on traditional breeding techniques. The development of modern molecular biology technology and the successful application of transgenic technology in cotton have provided new ideas and methods for improving cotton quality. Therefore, the use of genetic engineering technology can provide new solutions for improving cotton fiber quality. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a AgKATA The application of genes in optimizing cotton fiber quality can solve the technical problems of existing cotton fibers being not long enough and not fine enough.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is: to provide a AgKATA The gene has a nucleotide sequence as shown in SEQ ID NO.1.

[0006] The present invention also discloses a method comprising AgKATA Gene expression vector.

[0007] The present invention also discloses a method comprising AgKATA Gene or expression vector.

[0008] The present invention also discloses AgKATA Application of genes, expression vectors or cells in optimizing cotton fiber quality.

[0009] On the basis of the above technical solution, the present invention can also be improved as follows: Furthermore, optimizing the quality of cotton fiber is to increase the length of cotton fiber, reduce the fineness of cotton fiber, reduce the thickness of cotton fiber cell wall or reduce the content of hydrogen peroxide in cotton fiber cells.

[0010] The present invention also discloses a method for cultivating transgenic cotton. AgKATA The gene, expression vector or cell is transferred into the target cotton to obtain transgenic cotton, and the obtained transgenic cotton has at least one of the following characteristics: (1) The fiber length of transgenic cotton is longer than that of target cotton; (2) The fiber fineness of transgenic cotton is smaller than that of target cotton; (3) The fiber cell wall thickness of transgenic cotton is smaller than that of target cotton; (4) The content of hydrogen peroxide in the fiber cells of transgenic cotton is lower than that of the target cotton.

[0011] The beneficial effects of the present invention are: the present invention specifically expresses AgKATA Gene reduces the accumulation of H2O2 in cotton fiber cells. H2O2 is a signal molecule for secondary wall synthesis. By reducing the level of H2O2, the transcription level of genes related to secondary wall synthesis can be downregulated, the deposition of crystalline cellulose can be reduced, the synthesis of secondary wall can be delayed, the thickness of the cell wall of mature cotton fibers can be reduced, the fiber lengthening can be promoted, the mature cotton fibers can be made longer and thinner, and the length and fineness of cotton fibers can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a physical picture of cotton ovules after being treated with different concentrations of DMTU; Figure 2 The fiber length on the ovule after treatment with different concentrations of DMTU (n ≥ 30), scale = 2 mm; Figure 3 The expression changes of GhCesA4 gene after treatment with different concentrations of DMTU; Figure 4 The expression changes of GhCesA7 gene after treatment with different concentrations of DMTU; Figure 5 The expression changes of GhCesA8 gene after treatment with different concentrations of DMTU; Figure 6 The expression changes of GhCLT1 gene after treatment with different concentrations of DMTU; Figure 7 The expression changes of GhCLT2 gene after treatment with different concentrations of DMTU; Figure 8 The deposition of crystalline cellulose after treatment with different concentrations of DMTU; Fig. 9 is the crystalline cellulose deposition concentration after treatment with different concentrations of DMTU; Fig.10 for pE6::AgKATA Flowchart of plant expression vector construction; Fig.11 for AgKATA exist pE6::AgKATA Detection of transcript levels in materials; Fig.12 for pE6::AgKATA Results of H2O2 content detection in fibers of transgenic and recipient cotton at different developmental stages; Fig.13 for pE6::AgKATA Physical picture comparing the fiber length of transgenic and wild-type cotton; Fig.14 for pE6::AgKATA Statistics of mature fiber length of transgenic and wild-type cotton; Fig.15 for pE6::AgKATA Cross-section of mature fiber of transgenic and wild-type cotton; Fig.16 for pE6::AgKATA Statistics of mature fiber cell wall thickness of transgenic and wild-type cotton. DETAILED DESCRIPTION

[0013] The specific embodiments of the present invention are described below to facilitate the understanding of the present invention by those skilled in the art. If the specific conditions are not specified in the examples, the methods are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturers are not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, as long as various changes are within the spirit and scope of the present invention defined and determined by the attached claims, these changes are obvious, and all inventions and creations using the concept of the present invention are protected.

[0014] The sources of reagents used in the following examples are shown in Table 1, and the culture medium formula is shown in Table 2; materials and methods not specifically described are referred to in the Molecular Cloning Laboratory Manual (Sambrook and Russell, 2001).

[0015] Table 1 Reagent purchase information Main reagents Origin paraffin Shanghai Shenggong Bioengineering Co., Ltd. Agar powder Shanghai Shenggong Bioengineering Co., Ltd. DMTU (N,N'-dimethylthiourea) Bioisco Acetosyringone Amersco Hydrogen Peroxide Kit Suzhou Grace Biotech Table 2 Culture medium formula Culture medium name Medium formulation BT I (50×) <![CDATA[13.608g / L KH2PO4+0.31g / L H3BO3+0.0121g / L Na2MO4·2H2O]]> BT II (50×) <![CDATA[16.652g / L CaCl2+0.042g / L KI+0.0012g / L CoCl2·6H2O]]> BT III (50×) <![CDATA[24.05g / L MgSO4·7H2O+0.846g / L MnSO4·H2O+0.432g / L ZnSO4·7H2O+0.00125g / LCuSO4·5H2O]]> BT IV (50×) <![CDATA[126.388g / L KNO3]]> BT V (50×) <![CDATA[0.418g / L FeSO4·7H2O+0.56g / L Na2EDTA]]> BT VI (50×) <![CDATA[0.0246 g / L C6H6N2O (Nicotinamide) + 0.0411 g / L C8H 11 O3N·HCl (VB6) + 0.0675 g / L C 12 H 17 ON4SCl·HCl (VB1)]]> BT basic medium (1L) <![CDATA[20 mL BT I~VI (50×) + 18 g glucose + 3.6 g fructose, adjusted to pH = 5. After autoclaving, cool and add the mother liquor of sodium indole-3-acetate (IAA) and potassium gibberellate (GA3) to their final concentrations of 5 μM and 0.5 μM, respectively.]]> MSB IV (100X) <![CDATA[2.78g FeSO4·7H2O+3.732g Na2EDTA·2H2O]]> MSBV (1000X) <![CDATA[0.02 g CuSO4·5H2O+0.25g Na2MoO4·2H2O+6.2g H3BO3+ 0.83g KI+8.6g ZnSO4·7H2O+16.901g MnSO4·H2O+0.025g CoCl2·6H2O]]> The present invention AgKATA The nucleotide sequence of the gene (SEQ ID NO.1) is as follows: The sequences of the primers used in the present invention are shown in Table 3.

[0016] Table 3 Primer sequence list

[0017] Example 1 Measurement of fiber length after ovule in vitro culture The ovules of wild-type upland cotton Jimian 14 at 0 DPA were cultured in vitro and cultured in BT medium for 12 days. At this time, the fiber cells have not yet entered the secondary wall synthesis stage. The ovules with the same growth trend were transferred to the culture medium supplemented with different concentrations of DMTU and cultured for 4 days to detect the fiber growth. Figure 1 As shown, after combing and measuring the fiber length, Figure 2 Compared with the control MOCK group (1.32±0.21cm), the fiber length of the fiber with 150μM DMTU (1.41±0.18cm) did not change significantly, while the fiber length of the fiber with 250μM and 350μM DMTU increased significantly, with the fiber length of 350μM DMTU being 1.75±0.15cm, which was the most significant change. Therefore, the addition of 250μM and 350μM DMTU promotes fiber elongation.

[0018] Example 2 Determination of expression levels of genes related to secondary wall synthesis after cotton fibers were treated with different concentrations of DMTU The same culture mode was adopted, and the ovules were transferred to BT medium containing different concentrations of DMTU. After 4 days of treatment, samples were taken to detect the transcription levels of genes related to secondary wall synthesis. Cotton fiber RNA treated with different concentrations of hydrogen peroxide was extracted according to the instructions of the RNA Rapid Extraction Kit (Beijing Aidelai Company). Reverse transcription was performed according to the instructions of the Reverse Transcription Kit (Takara Company). RT primers were designed according to different cellulose synthase sequences for RT-PCR amplification.

[0019] The RT-PCR specific amplification system is shown in Table 4: Table 4 Parameters of RT-PCR specific amplification system

[0020] The amplification conditions were as follows: temperature at 95°C, time for 3 min; temperature at 95°C, time for 20 sec; temperature at 56°C, time for 20 sec; temperature at 72°C, time for 30 sec; and repeated for 40 cycles.

[0021] According to the Ct value of the amplification result, the amount of template was estimated to determine whether it could be used for gene expression analysis. The Ct value should be between 16 and 22. Bio-Rad CFX Manager and Excel software were used for data processing and analysis when calculating the expression level of the target gene.

[0022] Result analysis: Figure 3-Figure 7 As shown, after adding 250μM and 350μM DMTU, the expression of secondary wall cellulose synthase genes GhCesA4, GhCesA7, GhCesA8 and chitinase-like genes GhCTL1 and GhCTL2 were significantly downregulated compared with the control, among which the GhCTL2 gene was most significantly inhibited, but the addition of 150μM DMTU did not change significantly compared with the control.

[0023] Example 3 Observation of cellulose deposition A large amount of cellulose is synthesized during the secondary wall formation stage. Cellulose is synthesized by cellulose synthases (CESAs) in the plasma membrane. Each CESA forms highly crystalline cellulose microfibrils by polymerizing UDP-glucose, and the overall structure of cellulose microfibrils is different between the primary wall and the secondary wall. The most obvious is that the degree of polymerization and crystallinity of cellulose in the secondary wall are higher and easier to observe. Therefore, cellulose crystallization is an important feature of the fiber cell wall.

[0024] The same culture mode was adopted and the cells were cultured on BT medium with different concentrations of DMTU for 4 days. The fiber samples were evenly dispersed in distilled water and the crystalline cellulose in the fibers treated with different concentrations of DMTU was observed by birefringence microscopy using an IX81 inverted microscope system. The results are shown in Figure 2. Figure 8 As shown in the figure, it can be seen that after adding hydrogen peroxide, the crystalline cellulose signal of the fiber is significantly enhanced compared with the control, and the intensity increases with the increase of the added concentration.

[0025] The cellulose content determination method refers to the fiber content determination kit of Suzhou Grace Company.

[0026] Compared with the control, the cellulose crystal signal decreased after adding DMTU, but the difference was not significant by direct observation. In order to further determine whether the cellulose deposition was affected, the cellulose content was measured after four days of treatment. The results are as follows: Fig. 9 shown.

[0027] Results: Compared with the control (15.81±0.9 mg / g), the cellulose content of 150μM DMTU did not change significantly. After treatment with 250μM DMTU and 350μM DMTU, the cellulose content of the 250μM DMTU treatment group was 13.09±0.78 mg / g, which was 17% lower than the control; the cellulose content of the 350μM DMTU treatment group was 11.06±0.69 mg / g, which was 30% lower than the control. This indicates that during the rapid elongation period, the addition of a certain concentration (10-50μM) of hydrogen peroxide will upregulate the expression of genes related to secondary wall synthesis of cotton fibers, while promoting the deposition of crystalline cellulose, resulting in shorter fibers.

[0028] Example 4 Agrobacterium tumefaciens catalase gene AgKATA Clone (1) Obtained through the online website (http: / / crispr.hzau.edu.cn / CRISPR / ) AgKATA Full-length cDNA; (2) designing primers, wherein the sequences of the upstream primer 1 and the downstream primer 2 are shown as SEQ ID NO. 2 and SEQ ID NO. 3, respectively; (3) Using total DNA of Agrobacterium tumefaciens as template for cloning AgKATA The Agrobacterium tumefaciens strains with the gene were maintained in the laboratory; (4) Amplify according to the Phanta Super Fiderlity DNA Polymerase Kit; The PCR reaction system is shown in Table 5: Table 5 PCR reaction system parameters

[0029] (5) Amplification conditions: temperature 95°C, time 3 min; temperature 95°C, time 15 sec; temperature 56°C, time 15 sec; temperature 72°C, time 130 sec; repeat 35 cycles; (6) After amplification, the corresponding DNA bands were recovered by agarose electrophoresis, cloned into a blunt-end vector and sent to Sangon Biotech Co., Ltd. for sequencing verification.

[0030] Example 5 Construction of target gene overexpression vector The recovered vector and target fragment were connected according to the ClonExpress Ⅱ new generation recombination cloning kit. The construction process is as follows: Fig.10As shown, the main elements of the vector are indicated, GUS::NPTII represents the fusion gene of glucuronidase and neomycin phosphotransferase; NOS represents the terminator; 35S represents the plant constitutive promoter derived from cauliflower mosaic virus; E6 represents the fiber-specific promoter; the specific steps are as follows: (1) Amplified AgKATA Fragment; (2) Preparation of linearized vector: Extract the original empty plasmid (pCB2016), digest it with EcoRI, recover the target fragment, and store it at -20°C for future use; (3) Recombination: Calculate the amount of insert fragment and linearized vector required according to the instructions. The specific system is shown in Table 6. Table 6 Recombination system parameters

[0031] (4) After gently tapping the tube wall to mix, centrifuge at low speed and place in a PCR instrument to react at 37°C for 30 min to obtain the recombinant product; (5) Transformation of recombinant products: refer to the instructions for “DH5α Competent E. coli Strain, Vazyme #502”; (6) Identification of recombinant products: Pick a single colony from the plate and place it in LB medium supplemented with Km for PCR verification. The system is shown in Table 7. Table 7 PCR verification system parameters

[0032] The amplification conditions were as follows: temperature at 95°C, time for 3 min; temperature at 95°C, time for 30 sec; temperature at 55°C, time for 30 sec; temperature at 72°C, time for 1 min; temperature at 72°C, time for 5 min; and repeated for 35 cycles.

[0033] (7) The band size is correct, and the positive recombinant clone is finally confirmed by sequencing.

[0034] Example 6 Agrobacterium and genetic transformation of cotton 1. Use electroporation to introduce the constructed plant expression vector plasmid into Agrobacterium LBA4404 With reference to the Bio-RAD MicroPulser user manual, the above plant expression vector plasmid was introduced into Agrobacterium LBA4404 by electroporation transformation.

[0035] 2. AgKATA Overexpression vector integrated into the upland cotton genome Cotton was genetically transformed using the Agrobacterium-mediated method (Luo et al., 2007). The transgenic cotton plants obtained were screened by GUS staining. The GUS-positive seedlings were placed in clean water and cultured at 22°C for 1 week before being transplanted to a greenhouse for routine management.

[0036] Example 7 Extraction and expression level identification of transgenic upland cotton RNA Transgenic cotton fiber RNA was extracted according to the instructions of RNA rapid extraction kit (Beijing Adelaide Company), and reverse transcription was performed according to the instructions of reverse transcription kit (Takara Company). Upstream specific primer 6 and downstream specific primer 6 were designed according to the sequence for RT-PCR amplification.

[0037] The RT-PCR specific amplification system is shown in Table 8: Table 8 RT-PCR specific amplification system parameters

[0038] The amplification conditions are: temperature 95°C, time 3min; temperature 95°C, time 20sec; temperature 56°C, time 20sec; temperature 72°C, time 30sec; repeat 40 cycles. According to the Ct value of the amplification result, estimate whether the amount of template can be used for gene expression analysis.

[0039] Will build AgKATA Overexpression vector pE6::AgKATA The transgenic plant was transferred into the cotton hypoblast by Agrobacterium-mediated method, and the transgenic seedlings were obtained through plant tissue culture. The positive plant species were then identified by GUS histochemical staining. pE6::AgKATA In the greenhouse, 6 independent transformants and more than 100 transgenic cotton plants were obtained. Total RNA was extracted from the bolls of transgenic cotton at 8 DPA, and cDNA was synthesized and tested by Real-Time PCR. AgKATA Transcription levels of pE6::AgKATA Different transformants of transgenic cotton, error bars represent the standard deviation of three replicates. Fig.11 As shown, the gene can be transcribed normally in cotton.

[0040] Example 8 Determination of hydrogen peroxide content in transgenic cotton seeds The hydrogen peroxide in plant tissues was extracted according to the hydrogen peroxide kit of Suzhou Grace Biotechnology Co., Ltd.

[0041] The H2O2 content in the fibers of transgenic materials E6-KATA-1, E6-KATA-18 and wild type at 12DPA, 14DPA, 16DPA and 18DPA was measured. Fig.12 As shown, WT represents wild-type cotton; EK1-1, EK1-5, EK18-8 and EK18-9 represent pE6::AgKATA Different transformants of transgenic cotton.

[0042] Result analysis: As can be seen from the figure, the H2O2 content of E6-KATA-1 transformant was significantly lower than that of the wild type in the fiber at 12-16 DPA, and was basically the same as the wild type in the fiber at 18 DPA. Among them, the H2O2 content of E6-KATA1-1 changed most significantly in the fiber at 12 DPA, which was 33% lower than that of the control. The H2O2 content of E6-KATA1-5 decreased most significantly in the fiber at 14 DPA, which was 47% lower than that of the control. The H2O2 content of the transformant E6-KATA-18 was significantly lower than that of the control in the fiber at 12 DPA, and was basically the same as that of the control in the fiber at 16 DPA. This shows that the H2O2 content of the transformant E6-KATA-18 was significantly lower than that of the control in the fiber at 12 DPA, and was basically the same as that of the control in the fiber at 16 DPA. AgKATA It can normally perform the function of clearing catalase in cotton; this gene is expressed in cotton fibers and can reduce the H2O2 level in cotton fibers.

[0043] Example 9 AgKATA Cotton length and cell wall thickness determination after genes were upregulated 1. Measurement of cotton fiber length Cotton fiber Fig.13 As shown, measure the mature fiber length: use a needle to split the fibers on the seeds in half, slowly straighten them without removing the fibers, then take a picture and use a ruler to measure the fiber length.

[0044] Result analysis: Fig.14 As shown, overexpression AgKATA After that, the mature fiber length of transgenic material E6-KATA1-1 was 2.75±0.07cm, and the mature fiber length of E6-KATA1-5 was 2.71±0.08cm, which were increased compared with the non-transgenic control (2.5±0.09cm), while the mature fiber length of E6-KATA-18 did not change significantly compared with the wild type.

[0045] 2. Paraffin section (1) Fixation of materials: Take a small strand of combed cotton fiber and fix it with a white thread at both ends 1 cm apart, add 1 mL of FAA fixative, evacuate and leave for one week; (2) Discard the fixative, wash with clean water, add 1 mL of softening solution, evacuate and place for one week; (3) Pour away the waste liquid, add 1 mL of dehydration solution I, soak for 1 hour, and then discard the waste liquid; then add dehydration solution II, soak for 1 hour, and then discard the waste liquid; and so on, until the dehydration solution IV is added and the soaking is completed; (4) Melt paraffin, mix paraffin and tert-butyl alcohol in a volume ratio of 1:1, add to a centrifuge tube, and dry at 65°C for 2.5 h; (5) Repeat step (4) once; (6) Remove the mixture of tert-butyl alcohol and paraffin, add pure paraffin, and dry at 65°C for 6 hours; (7) The dried fibers are embedded and then cooled naturally.

[0046] 3. Sectioning, dewaxing, sealing and observation (1) Heat the paraffin and stick the solidified material to the slicer; (2) Set the slice thickness to 10 µm, slice, and place the cut wax tape slices in a proper amount of slightly warm water to unfold; (3) Apply a small amount of Haupt paste evenly on a glass slide and dry it at 65°C for 2 days; (4) Transferring the wax tape slices obtained in step (2) onto a glass slide and drying the slides at 42°C; (5) Place the wax tape slices after baking on the slice rack and add turpentine to dewax. The dewaxing time is 1 hour. Take out the slices in the middle to observe the dewaxing condition. (6) Place the dewaxed wax tape slice on a glass slide, drop the sealing agent on the surface of the wax tape slice, then slowly cover it with a cover glass and dry it in an oven; (7) The slices were observed and photographed under a normal fluorescence microscope. Fig.15 shown.

[0047] Paraffin sections of mature cotton fibers were observed and the thickness of fiber cell walls was counted. Fig.16 , scale bar = 5 μm, where WT represents wild-type cotton; E6-KATA1-1, E6-KATA1-5, E6-KATA18-8 and E6-KATA18-9 represent pE6::AgKATA Different transformants of transgenic cotton.

[0048] Result analysis: It can be seen from the figure that the thickness of the mature fiber cell wall of the wild type is 5.369±0.54μm, and the thickness of the mature fiber cell wall of the overexpressed transgenic material E6-KATA-1 is significantly thinner than that of the wild type. The thickness of the mature fiber cell wall of the single plant E6-KATA1-1 is 4.364±0.51μm, which is 18.72% lower than that of the wild type; the thickness of the mature fiber cell wall of the single plant E6-KATA1-5 is 4.295±0.43μm, which is 20% lower than that of the wild type. The thickness of the mature fiber cell wall of the transgenic material E6-KATA-18 is thinner than that of the wild type. Among them, the thickness of the mature fiber cell wall of the single plant E6-KATA18-8 is 4.865±0.61μm, which is 9.3% lower than that of the wild type; the thickness of the mature fiber cell wall of the single plant E6-KATA18-9 is 4.754±0.6μm, which is 11.45% lower than that of the wild type. Therefore, in cotton fiber cells, AgKATA The gene can eliminate catalase in cotton, thereby reducing the thickness of the cell wall. The mature fibers of transgenic cotton are longer and thinner than those of wild-type cotton.

[0049] The above embodiments show that the present invention can be achieved by AgKATA The catalase in cotton is removed by gene, the hydrogen peroxide content in cotton fiber cells is reduced, and the length and fineness of cotton fibers are improved. The method of the invention is simple and easy to implement, has significant effects, and has good market prospects.

Claims

1. A AgKATA A gene characterized by Said AgKATA The nucleotide sequence of the gene is shown in SEQ ID NO.

1.

2. An expression vector, characterized in that: Containing the claim 1 AgKATA Gene.

3. A cell, characterized in that Containing the claim 1 AgKATA The gene or the expression vector according to claim 2.

4. The method according to claim 1 AgKATA Use of the gene or the expression vector according to claim 2 or the cell according to claim 3 in optimizing cotton fiber quality.

5. The use according to claim 4, characterized in that: The optimization of cotton fiber quality is to increase the length of cotton fiber, reduce the fineness of cotton fiber, reduce the thickness of cotton fiber cell wall or reduce the content of hydrogen peroxide in cotton fiber cells.

6. A method for cultivating transgenic cotton, characterized in that: The claim 1 AgKATA The gene or the expression vector according to claim 2 or the cell according to claim 3 is transferred into target cotton to obtain transgenic cotton, wherein the transgenic cotton has at least one of the following characteristics: (1) The fiber length of transgenic cotton is longer than that of target cotton; (2) The fiber fineness of transgenic cotton is smaller than that of target cotton; (3) The fiber cell wall thickness of transgenic cotton is smaller than that of target cotton; (4) The content of hydrogen peroxide in the fiber cells of transgenic cotton is lower than that of the target cotton.

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