Application of GDSL type esterase / lipase gene GbGEELP in improvement of cotton fiber quality character

Abstract

The invention discloses application of a GDSL type esterase / lipase gene GbGELP in improvement of cotton fiber quality characters, and belongs to the field of biotechnology application. According to the invention, a biotechnology is utilized to clarify that the GbGELP gene has a promotion effect on fiber cell elongation. Researches show that the silent cotton GDSL type esterase / lipase gene GbGELP inhibits fiber initiation and elongation, and the root length and the number of stem hairs of an arabidopsis thaliana plant with heterologous expression of GbGELP are both superior to those of a wild type control. The transcription factor GhHDG2 is combined with an HAHR1-A-box element of a GbGELP (Gossypium barbadense Gossypium barbadense Gossypium barbadense Gossypium barbadense) promoter to promote the expression of GbGELP. The GbGELP plays an important role in improving the quality character of cotton fibers and cultivating new varieties of high-quality cotton fibers and has an application prospect.

Description

Technical Field

[0001] The present invention belongs to the field of biotechnology application, and relates to the application of a GDSL-type esterase / lipase gene GbGELP in improving cotton fiber quality traits. The present invention screens out a GDSL-type esterase / lipase gene derived from sea island cotton (Gossypium barbadense), named GbGELP, the gene ORF is 1068bp in length, and encodes 355 amino acids. A secondary separation population is constructed by hybridizing a high-quality fiber sea-land introgression material CSSL47 with a receptor parent TM-1, and a GDSL-type esterase / lipase gene GbGELP is identified by combining fine positioning, displacement mapping, gene structure and expression analysis. The expression level of the gene in different fiber development stages of CSSL47 is higher than that of TM-1, and the expression level is highest in the fiber 15 days after flowering. Inhibiting the expression of GbGELP in cotton results in fewer protrusions in fiber cells and shorter fiber length. GbGELP was heterologously expressed in Arabidopsis, and the root length and root cells of transgenic Arabidopsis were both longer, the rosette leaves grew more vigorously, and the leaf hairs and stem hairs increased, which significantly promoted plant growth. The present invention uses biotechnology to clarify that GbGELP has a promoting effect on plant cell elongation, and proposes that overexpression of GbGELP can promote fiber cell elongation and improve fiber quality in breeding. Background Art

[0002] Upland cotton (Gossypium hirsutum) and Sea island cotton (Gossypium barbadense) are two allotetraploid cultivated cotton species. Upland cotton accounts for more than 90% of the global cotton planting area and is characterized by high fiber yield and wide adaptability. Sea island cotton has excellent fiber quality and disease resistance. At present, the important bottleneck restricting the further improvement of cotton varieties is the narrow genetic background of upland cotton and the negative correlation between fiber quality and yield. By creating Sea island cotton chromosome segment introgression lines (CSILs) with upland cotton background, introducing the excellent fiber quality genes of Sea island cotton into upland cotton is an effective way to broaden the genetic background of upland cotton, break the negative correlation between quality and yield, and obtain new high-yield and high-quality cotton varieties.

[0003] Chromosome segment introgression lines are also called single segment introduction lines (SSIL), single segment substitution lines (SSSL), near isogenic introduction lines (NIL), chromosome replacement lines (CSSL), etc. They are mainly constructed through backcrossing and selfing, combined with molecular marker-assisted selection (MAS), and are a set of families with only one or a few specific donor chromosome segments, while the other genetic backgrounds are exactly the same as those of the recipient parents. The main characteristics of this type of family are: the genome of each introgression line individual contains only one or a few chromosome segments from the donor parent, and the rest are the same as the recurrent parent; the introgression line population is a permanent isolation population, and multi-point phenotypic identification can be carried out for many years; the target segment can be divided into segments with shorter introgression lengths after backcrossing and recombination. In addition, the use of chromosome segment introgression lines to carry out target trait investigations and gene effect studies can minimize the influence of genetic background between strains, which is of great significance for the positioning of QTLs for important traits.

[0004] At the same time, the use of chromosome fragment introgression lines is also an ideal material for QTL fine positioning. There are generally two methods: the first is to use the overlapping groups in the introgression line to finely locate the QTL through the permutation mapping method; the second method is to construct a secondary segregation population of QTL for QTL fine positioning. Xiao et al. (2023) used a single segment substitution line (CSSL-106) and its recurrent parent CCRI45 to backcross and construct a secondary segregation population of 2852 strains. The fiber length-related QTLqFL-A12-5 was finely located in the 18.8Kb region on chromosome A12, and GH_A12G2192 (GhTPR), which encodes a tetratripeptide repeat superfamily protein, was identified as a candidate gene for regulating cotton fiber development. Feng et al. (2022) selected the genetically stable introgression line IL197 of Upland cotton × Asian cotton with small bolls and small cotton seeds, constructed F2 and F3 secondary segregation populations, and further narrowed the QTL q(BW+SI)-A12-1 on chromosome A12 that simultaneously controls boll weight (BW) and seed index (SI) to 60.09 kb through substitution mapping. RT-qPCR analysis preliminarily identified TIP41-like family protein (TIP41L) as a candidate gene.

[0005] GDSL lipase is a class of lipid hydrolase (lipolyticzyme) family, which is widely found in bacteria and plants. In plants, GDSL lipase is found to be a multifunctional enzyme involved in many physiological processes, including plant growth, development and resistance to biotic and abiotic stresses. Studies have shown that Arabidopsis GDSL lipase genes GLIP1 and GLIP2 are important for regulating systemic resistance and pathogen defense, respectively (Kwon et al. 2009; Lee et al. 2009). Rice GER1 is a GDSL motif encoding gene that regulates coleoptile elongation through light-JA interaction. WDL1 is a member of the GDSL lipase family and plays an important role in the biosynthesis of wax and epidermal cell layers (Park et al. 2010). Pepper GDSL lipase plays an important role in coping with abiotic stress and pathogen defense (Hong et al. 2008). Tomato GDSL1 protein is essential for the extracellular deposition of cutin polyesters in the fruit cuticle (Girard et al. 2012). GDSL lipase also plays a role in cotton fiber development at different stages of dominant expression. GhMYB1 regulates the specific expression of GhGDSL in cotton fiber at 19-25DPA, thereby promoting secondary cell wall biosynthesis and affecting fiber quality (Yadav et al. 2017). GhGLIP is expressed in developing ovules and elongating fibers at 5-15DPA; overexpression of GhGLIP in Arabidopsis leads to enhanced seed development, suggesting that it plays an important role in the development of cotton ovules, fibers and seeds (Ma et al. 2018). GhirGDSL26 enhances cotton drought stress tolerance by increasing H2O2 activity and reducing SOD activity (Liu et al. 2023). So far, the functions of most GDSL lipase genes in cotton have not been clearly understood. Therefore, it is of great significance to explore and analyze the functional characteristics and breeding value of cotton GDSL lipase genes in improving fiber quality. Summary of the invention

[0006] The purpose of the present invention is to provide an application of a GDSL type esterase / lipase gene GbGELP related to cotton fiber quality traits.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] In the first aspect, the present invention claims the use of the GbGELP gene as shown in SEQ ID NO.1 or a biological material related to the GbGELP gene in the following (a1) or (a2) or (a3) ​​or (a4):

[0009] (a1) improving the quality traits of cotton fiber, or preparing products for improving the quality traits of cotton fiber;

[0010] (a2) improving the quality of cotton fibers, or preparing products for improving the quality of cotton fibers;

[0011] (a3) cultivating new high-quality cotton fiber germplasm, or preparing products for cultivating new high-quality cotton fiber germplasm;

[0012] (a4)) Promote plant growth.

[0013] Furthermore, the biological material related to the GbGELP gene is the biological material described in (b1) or (b2) or (b3) below:

[0014] (b1) protein GbGELP encoded by the GbGELP gene;

[0015] (b2) primers for amplifying the full-length coding sequence of the GbGELP gene;

[0016] (b3) Biological material containing the GbGELP gene.

[0017] Furthermore, the protein GbGELP encoded by the GbGELP gene in (b1) has an amino acid sequence as shown in SEQ ID NO.2.

[0018] Furthermore, the primers used to amplify the full-length coding sequence of the GbGELP gene in (b2) are shown as SEQ ID NO.5 and SEQ ID NO.6.

[0019] Furthermore, the biological material containing the GbGELP gene described in (b3) is at least one of the following (c1) to (c9):

[0020] (c1) an expression cassette containing the GbGELP gene;

[0021] (c2) a recombinant vector containing the GbGELP gene, or a recombinant vector containing the expression cassette described in (c1);

[0022] (c3) a recombinant microorganism containing the GbGELP gene, or a recombinant microorganism containing the expression cassette described in (c1), or a recombinant microorganism containing the recombinant vector described in (c2);

[0023] (c4) a transgenic plant cell line containing the GbGELP gene, or a transgenic plant cell line containing the expression cassette of (c1), or a transgenic plant cell line containing the recombinant vector of (c2);

[0024] (c5) transgenic plant tissue containing the GbGELP gene, or transgenic plant tissue containing the expression cassette described in (c1), or transgenic plant tissue containing the recombinant vector described in (c2);

[0025] (c6) a transgenic plant organ containing the GbGELP gene, or a transgenic plant organ containing the expression cassette described in (c1), or a transgenic plant organ containing the recombinant vector described in (c2);

[0026] (c7) a transgenic plant containing the GbGELP gene, or a transgenic plant containing the expression cassette described in (c1), or a transgenic plant containing the recombinant vector described in (c2);

[0027] (c8) tissue cultures produced from regenerable cells of the transgenic plant described in (c7);

[0028] (c9) Protoplasts produced from the tissue culture described in (c8).

[0029] Furthermore, the above application is to use the GbGELP gene as the target gene, overexpress the GbGELP gene through genetic engineering methods, improve cotton fiber quality traits, improve cotton fiber quality, cultivate new cotton high-quality fiber germplasm or promote the growth of target plants.

[0030] Furthermore, the plant is cotton or Arabidopsis thaliana.

[0031] In a second aspect, the present invention claims a method for improving cotton fiber quality traits or enhancing cotton fiber quality, which involves overexpressing the GbGELP gene with a nucleotide sequence such as that shown in SEQ ID NO.1 in cotton to improve cotton fiber quality traits or enhance cotton fiber quality.

[0032] In a third aspect, the present invention claims a GbGELP gene related to cotton fiber quality traits, wherein the gene has a nucleotide sequence as shown in SEQ ID NO.1.

[0033] In a fourth aspect, the present invention claims protection for a biological material related to the above-mentioned GbGELP gene, wherein the biological material is the biological material described in (d1) or (d2) or (d3) below:

[0034] (d1) a protein GbGELP encoded by the GbGELP gene having an amino acid sequence as shown in SEQ ID NO.2;

[0035] (d2) primers as shown in SEQ ID NO.5 and SEQ ID NO.6 for amplifying the full-length coding sequence of the GbGELP gene;

[0036] (d3) An expression cassette, recombinant vector, transgenic cell line or recombinant bacteria containing the GbGELP gene.

[0037] The present invention shows that when the nucleotide sequence of the GDSL-type esterase / lipase gene GbGELP shown in SEQ ID NO.1 is silenced in the introgression line CSSL47, compared with the control plants, the silenced plants show fewer 0-day ovule fiber cell protrusions and shorter fiber length, inhibiting fiber initiation and elongation; when the nucleotide sequence of the GDSL-type esterase / lipase gene GbGELP shown in SEQ ID NO.1 is overexpressed in Arabidopsis, compared with the wild type (WT), the overexpressing Arabidopsis strain has longer roots, longer root cells, more vigorous rosette leaf growth, more leaf hairs and stem hairs, and promotes plant growth.

[0038] The present invention uses a high-quality fiber marine-continental introgression material CSSL47 to hybridize with the recipient parent TM-1 to construct a secondary segregation population, combines the resequencing data of CSSL47, obtains a precise introgression segment, develops InDel markers for the insertion / deletion sites on the introgression segment, conducts linkage analysis between the fiber quality phenotypic values ​​and genotypes of the secondary segregation population, identifies a QTL qFM-A11 for fiber fineness, and further uses the recombinants in the candidate segment for replacement mapping to obtain the candidate interval of the QTL. Combined with the differential expression characteristics of genes in the candidate interval at different fiber development stages of CSSL47 and TM-1, a GDSL-type esterase / lipase gene GbGELP was discovered, ID number GB_A11G1593. The expression level of this gene in CSSL47 at different fiber development stages is higher than that of TM-1, and the expression level is highest in 15-day fiber. Compared with TM-1, the parent CSSL47 has advantages in fiber length, fiber strength, and fiber fineness. In the introgression line CSSL47, the GDSL esterase / lipase gene GbGELP with a nucleotide sequence as shown in SEQ ID NO.1 was silenced. Compared with the control plants, the silenced plants showed fewer protrusions of 0-day ovule fiber cells, shorter fiber length, and significantly inhibited fiber initiation and elongation; in Arabidopsis, the GDSL esterase / lipase gene GbGELP with a nucleotide sequence as shown in SEQ ID NO.1 was overexpressed. Compared with the wild type (WT), the overexpressing Arabidopsis strain had longer roots, longer root cells, more vigorous rosette leaf growth, more leaf hairs and stem hairs, and promoted plant growth. The above results indicate that GbGELP plays a role in promoting cotton fiber development and plant growth and development.

[0039] The development process of the technical solution of the present invention specifically includes the following steps:

[0040] 1. A high-quality fiber marine-continental introgression material CSSL47 was hybridized with TM-1 to construct a (CSSL47×TM-1) F2 secondary segregation population. The fiber quality traits (fiber length, fiber strength, micronaire value, fiber uniformity and fiber elongation) of the secondary segregation population were investigated to obtain phenotypic data.

[0041] 2. Combined with the whole genome resequencing information of CSSL47, compared with the homologous sequence of TM-1, analyzed the insertion / deletion sites on the A11 chromosome introgression fragment, developed InDel markers, and screened polymorphic InDel primers. Using polymorphic InDel primers, genotype identification of the secondary segregation population was performed to obtain genotyping data.

[0042] 3. Use F2 plants and F 2:3 The fiber quality test data of the lines were combined with the InDel marker genotype data of the F2 plants for QTL mapping, and a QTL qFM-A11 for fiber fineness was detected. Combined with substitution mapping, the candidate interval of the QTL was identified.

[0043] 4. Combining the expression of genes in the candidate interval at different fiber development stages between parents, a GDSL-type esterase / lipase gene GbGELP was identified as a candidate gene for the fiber fineness QTL. Its expression in different fiber development stages of CSSL47 was higher than that of TM-1, and the highest expression level was in the fiber 15 days after flowering. The CDS sequence of the GbGELP gene is SEQ ID NO.1, and the encoded amino acid sequence is SEQ ID NO.2. Sequence analysis between parents showed that the gene had two non-synonymous SNP mutations in TM-1 and CSSL47.

[0044] 5. Comparative analysis of GDSL-type esterase / lipase genes in CSSL47 (GbGELP) and TM-1

[0045] In the promoter sequence of GbGELP, an A / T SNP variation was found in the HAHR1-box element sequence, forming two haplotypes of HAHR1-A / T-box. As a result, the transcription factor GhHDG2 can bind to the HAHR1-A-box from sea island cotton, but cannot bind to the HAHR1-T-box from upland cotton. GhHDG2 promotes GbGELP expression by binding to the HAHR1-A-box element of the GbGELP promoter.

[0046] 6. The present invention also constructed a GbGELP silenced strain. Compared with the control plant, the strain with silenced cotton GbGELP gene as shown in SEQ ID NO.1 had fewer ovule fiber cell protrusions and shorter fiber length on the day of flowering (0 day), indicating that silencing GbGELP significantly inhibited fiber initiation and elongation.

[0047] 7. The present invention also constructs a GbGELP-overexpressing Arabidopsis transgenic strain. Compared with the wild-type WT, the Arabidopsis strain heterologously expressing the cotton GbGELP gene shown in SEQ ID NO.1 has significantly longer roots, longer root cells, more vigorous rosette leaf growth, and more leaf and stem hairs. This indicates that overexpression of GbGELP significantly promotes cell elongation in Arabidopsis plants.

[0048] The advantages of the present invention are:

[0049] 1. The present invention uses linkage analysis and displacement mapping to identify a QTL (qFM-A11) related to fiber fineness in an introgression fragment in a marine-terrestrial introgression line material of high-quality fiber. Combined with the expression characteristics of genes in the candidate interval at different fiber development stages between the two parents CSSL47 and TM-1, a GDSL-type esterase / lipase gene GbGELP was preliminarily identified as the candidate gene of the QTL.

[0050] 2. According to the different haplotypes of GDSL-type esterase / lipase genes, the recombinant population can be divided into two categories, namely type 1 (G1 and G5) and type 2 (G2-G4). Statistical analysis found that there were significant differences in fiber fineness between individual plants corresponding to different haplotypes.

[0051] 3. The expression levels of GDSL-type esterase / lipase genes at different fiber development stages between the two parents were obtained through transcriptome data and further verified by quantitative analysis. The results showed that the expression level of this gene in CSSL47 at different fiber development stages was higher than that of TM-1, and the highest expression level was in the fiber 15 days after flowering, followed by the fiber 10 days after flowering, and low expression in the fiber 5 and 20-25 days after flowering. This indicates that this gene plays a role in the fiber initiation and elongation stages.

[0052] 4. Compared with TM-1, the parent CSSL47 has advantages in fiber length, fiber strength and fiber fineness; 2：4 In the recombinant population, different recombinant types have advantages in fiber fineness, indicating that the GDSL-type esterase / lipase gene GbGELP has significant advantages in improving fiber quality traits and can be used to improve cotton fiber quality traits and cultivate new high-quality cotton varieties.

[0053] 5. Compared with the control plants, the cotton lines in which the GbGELP gene shown in SEQ ID NO. 1 was silenced had fewer protrusions in the ovule fiber cells at day 0 and shorter fiber length, indicating that silencing GbGELP significantly inhibited fiber initiation and elongation.

[0054] 6. Compared with the wild type (WT), the Arabidopsis strains overexpressing the cotton GbGELP gene as shown in SEQ ID NO.1 have significantly longer roots, longer root cells, more vigorous growth of rosette leaves, and more leaf and stem hairs, indicating that overexpression of the GbGELP gene promotes plant growth and development.

[0055] 7. By comparing the promoter sequences and binding element analysis of GDSL-type esterase / lipase genes in CSSL47 (GbGELP) and TM-1 (GhGELP), it was found that a HAHR1-box element sequence had an A / T SNP variation, forming two haplotypes of HAHR1-A / T-box. As a result, the transcription factor GhHDG2 can bind to the HAHR1-A-box from sea island cotton, but cannot bind to the HAHR1-T-box from upland cotton. GhHDG2 promotes GbGELP expression by binding to the HAHR1-A-box element of the GbGELP promoter. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 .Genetic positioning of fiber fineness QTL locus qFM-A11.

[0057] a The fiber fineness QTL locus qFM-A11 was found in F2 and F 2:3 The initial location of the QTL in the F2 and F 2:3 LOD curve of population positioning, LOD>2.5. bGenetic linkage map of the introgressed fragment of chromosome A11. c qFM-A11 substitution mapping and comparison of fiber fineness between different introgressed fragments and TM-1. ** indicates P<0.01, * indicates <0.05. d Comparison of mature fiber fineness between CSSL47 and TM-1, parents of the introgressed line of Sea Island cotton Hai7124 in the background of Upland cotton TM-1.

[0058] Figure 2 .Expression analysis of GDSL-type esterase / lipase genes in different fiber development stages of CSSL47 and TM-1.

[0059] a Heat map of the expression of candidate genes in the qFM-A11 interval at different fiber development stages in CSSL47 and TM-1. The red box shows the gene expression profiles of GDSL-type esterase / lipase genes in CSSL47 (GB_A11G1593) and TM-1 (GH_A11G1594). The numbers on the right side of the figure show the gene numbers of candidate genes in the qFM-A11 interval in CSSL47. b RT-qPCR analysis of GDSL-type esterase / lipase genes in fibers from 5 to 25 days after flowering of the two parents. c Distribution of differentially expressed genes (DEGs) in fibers from CSSL47 and TM-1 15 days after flowering. d GO enrichment analysis of upregulated DEGs in fibers from CSSL47 and TM-1 15 days after flowering.

[0060] Figure 3 Analysis of the expression patterns of fiber upregulated DEGs in CSSL47 and TM-1 at different fiber development stages 15 days after anthesis.

[0061] a Expression heat map of genes highly expressed in fibers 15-25 days after flowering among up-regulated DEGs. b GO enrichment analysis of genes highly expressed in fibers 15-25 days after flowering among up-regulated DEGs. c Expression pattern analysis of key genes related to cell wall. d Expression pattern of genes highly expressed 5-15 days after flowering among up-regulated DEGs. e GO enrichment analysis of genes highly expressed 5-15 days after flowering among up-regulated DEGs. f Expression pattern analysis of key genes related to plant hormones.

[0062] Figure 4 .Phenotypic analysis of transgenic Arabidopsis thaliana overexpressing the GbGELP gene.

[0063] a Identification of expression levels of transgenic Arabidopsis overexpressing the GbGELP gene. b Subcellular localization of GbGELP. c Phenotypic observation of root cells of GbGELP transgenic lines and wild-type WT, scale bar is 50 μm. d Comparative analysis of root cell length between transgenic Arabidopsis and WT. e Phenotypic observation of root length of GbGELP transgenic lines and WT. Scale bar is 1 cm. f Comparative analysis of root length of transgenic Arabidopsis and WT. g Observation of rosette leaf growth of GbGELP transgenic lines and WT. h Observation of stem epidermal hairs of GbGELP transgenic lines and WT. Scale bar is 2.5 mm. i Comparative analysis of the number of stem epidermal hairs of transgenic Arabidopsis and WT. j Phenotypic observation of the number of leaf epidermal hairs of GbGELP transgenic lines and WT. Scale bar is 2.5 mm. k Comparative analysis of the number of leaf epidermal hairs of transgenic Arabidopsis and WT.

[0064] Figure 5 . Fiber phenotype analysis of cotton with silenced GbGELP gene.

[0065] a Analysis of the expression level of GbGELP in CLCrV-GbGELP and CLCrV-A plants. b Comparison of fiber length at different developmental stages between CLCrV-GbGELP and CLCrV-A plants. Scale bar: 1 cm. c Comparative analysis of fiber length at different developmental stages between CLCrV-GbGELP and CLCrV-A plants. d Comparative analysis of fiber cell protrusions in ovules of CLCrV-GbGELP and CLCrV-A plants at day 0. Scale bar: 50 μm. ** indicates P < 0.01, * indicates < 0.05.

[0066] Figure 6 .Comparison of promoter sequences of GDSL-type esterase / lipase genes in CSSL47 and TM-1.

[0067] The green background is the motif of the GhHDG2 binding element HAHR1-box, and there is an A / T SNP difference between CSSL47 and TM-1. The blue background is the start codon position.

[0068] Figure 7 .GhHDG2 promotes GbGELP expression by binding to the HAHR1-box of the GbGELP promoter.

[0069] a Co-expression analysis of GhHDG2 and GbGELP at different fiber development stages. b Subcellular localization of GhHDG2. c Luciferase assay of GhHDG2 binding to HAHR1-box. d Dual luciferase reporter assay of GhHDG2 binding to HAHR1-box. Due to the presence of an A / T SNP variation in the HAHR1-box element (represented as HAHR1-A-box and HAHR1-T-box, respectively), GhHDG2 can bind to the HAHR1-A-box on the GbGELP promoter from CSSL47 but cannot bind to the HAHR1-T-box on the GhGELP promoter from TM-1. e Dual luciferase reporter assay of GhHDG2 binding to pGbGELP. LUC / REN analysis showed that GhHDG2 can bind to pGbGELP to activate gene expression. f GUS staining assay of GhHDG2 binding to HAHR1-box. g GUS activity assay showed that GhHDG2 could bind to the HAHR1-A-box of GbGELP but not to the mutated HAHR1-T-box element of GhGELP. DETAILED DESCRIPTION

[0070] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments.

[0071] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods.

[0072] Example 1 Identification of cotton fiber fineness QTL qFM-A11 by fine mapping and displacement mapping and discovery of its candidate genes

[0073] Through the fiber quality evaluation of the Sea Island Cotton Hai7124 introgression line population with a configured upland cotton TM-1 background for many years, a sea-land introgression line material CSSL47 with excellent fiber quality was found. Its fiber length (FL) and fiber strength (FS) were significantly higher than those of the receptor TM-1, and its micronaire value (FM) was significantly lower than that of TM-1 ( Figure 1 d, Table 1). The F2 secondary segregation population was configured with TM-1 (CSSL47×TM-1) to identify high-quality loci and candidate genes contained in the introgression fragment of CSSL47. Combined with the whole genome resequencing information of CSSL47, InDel markers were developed for the insertion / deletion sites on the introgression fragment, and polymorphic InDel primers were screened. The polymorphic InDel primers were used to identify the genotypes of the F2 plants in the secondary segregation population and obtain genotyping data. 2:3 The five fiber quality traits of the strains were investigated by phenotyping. 2:3 The fiber quality data of the strains were used for QTL mapping together with the InDel marker genotype data, and a fiber fineness (FM) QTL (qFM-A11) was detected ( Figure 1 a) Place F 2:3 47 recombinants of the population were planted and further F 2:4 The 47 recombinant strains were selected for genotyping and fiber quality trait investigation, and displacement mapping was carried out. The 47 recombinants were divided into 5 groups. The fiber fineness of the G2-G4 group was significantly lower than that of TM-1, but there was no significant difference with CSSL47. The fiber fineness of the G1 and G5 groups was significantly higher than that of L283, but there was no significant difference with TM-1. qFM-A11 was finely located between A11-18.48 and A11-18.88, with a size of 407kb ( Figure 1 b,c).

[0074] Table 1 Comparison of phenotypic values ​​of parents

[0075]

[0076]

[0077] Based on the comparison of candidate interval genes expression in different fiber development stages between TM-1 and CSSL47 parents ( Figure 2a), combined with the gene sequence information and functional annotation information, a GDSL-type esterase / lipase gene was found, which was expressed at higher levels than TM-1 in different fiber development stages of CSSL47, and was highest in 15-day-old fibers ( Figure 2 b) Sequence analysis between the two parents showed that the gene had two non-synonymous SNP mutations between the two parents. Subcellular localization results showed that it was a membrane-localized protein ( Figure 4 b). Based on the expression and gene sequence results, the GDSL-type esterase / lipase gene was preliminarily identified as the candidate gene for the fiber fineness QTL (qFM-A11).

[0078] Example 2 Analysis of GDSL-type esterase / lipase gene phenotype differences

[0079] The phenotypic differences in fiber fineness between the parents were calculated using the t-test method in statistics. The fiber length, fiber strength, and micronaire value of the parent CSSL were significantly better than those of TM-1 (Table 1). 2:4 The FM of group type 2 (G2-G3) is significantly better than that of group type 1 (G1 and G5) ( Figure 1 c).

[0080] Example 3 Transcriptome analysis of GDSL-type esterase / lipase genes in different fiber development stages of parents CSSL47 and TM-1

[0081] Fiber tissues of the parental CSSL47 and TM-1 at 5-25 DPA during fiber development were collected for transcriptome sequencing and quantitative detection to obtain the expression of GDSL-type esterase / lipase genes at different fiber development stages. The reads obtained by sequencing were compared with the TM-1 genome, and the expression level was calculated as the average expression level of monomeric genes per million transcripts TPM. Gene-specific quantitative primers were designed using Beacon Designer 7, and quantitative detection was completed using AB7500 Real-Time PCR. The CT values ​​of the internal reference primer and the quantitative primer were read, and the relative expression was calculated using the relative expression level = Calculate the relative expression data of genes and perform difference significance analysis. Figure 2 As shown in b, the expression level of this gene in different fiber development stages of CSSL47 was higher than that of TM-1, and the expression level was highest in 15-day fiber, followed by 10-day fiber, and low in 5-day and 20-25-day fiber, indicating that this gene plays a role in fiber initiation and elongation.

[0082] In order to clarify the pathways in which GDSL-type esterase / lipase genes may be involved in regulating fiber development, the differentially expressed genes (DEGs) and GO enrichment of fibers 15 days after flowering of the two parents were selected for analysis, referring to the characteristics of high expression of GDSL-type esterase / lipase genes at 15 days of fiber development. A total of 1935 DEGs (1512 up-regulated and 423 down-regulated genes in CSSL47) ( Figure 2 c). GO enrichment analysis was further performed on the 1512 upregulated DEGs ( Figure 2 d), and significantly enriched in cell wall development-related pathways (xyloglucan metabolism, hemicellulose metabolism, and cell wall polysaccharide metabolism, etc.) and plant hormone-related pathways (auxin and ethylene response signaling pathways). This indicates that the gene promotes fiber development by regulating the up-regulated expression of cell wall development-related genes and plant hormone-related genes.

[0083] Example 4 Fiber development expression characteristics and GO enrichment analysis of DEGs upregulated in CSSL47

[0084] By analyzing the expression patterns of 1512 upregulated DEGs in CSSL47 during fiber development from 5 to 25 days, we found that there were two main types: one was highly expressed genes from 15 to 25 days, and GO enrichment analysis showed that they were significantly enriched in cell wall development-related pathways ( Figure 3 ab); the other is highly expressed genes at 5-15 days, which are significantly enriched in auxin and ethylene response pathways and lipid transport pathways ( Figure 3 de). The expression patterns of key cell wall-related and hormone-related genes were further analyzed ( Figure 3 cf), and found that their expression patterns were consistent with the above analysis. This indicates that high expression of GbGELP promotes the upregulation of hormone-related genes such as auxin and ethylene response signaling pathways in the early stage of fiber elongation, and further promotes the expression of key genes for cell wall biosynthesis such as xyloglucan metabolism, hemicellulose metabolism, and cell wall polysaccharide metabolism in the late stage of fiber elongation, significantly promoting fiber cell elongation and regulating fiber quality improvement.

[0085] Example 5 GbGELP subcellular localization analysis

[0086] To verify the subcellular localization of GbGELP, we constructed the pBin-eGFP4 vector of the gene to be tested, which fused the target gene and eGFP protein (35S-targetgene-eGFP-NOS) under the control of the 35S promoter of cauliflower mosaic virus (CaMV) (Liu et al. 2014). The 35S-GbGELP-eGFP-NOS vector was injected into 5-week-old tobacco leaves by Agrobacterium. Three days after injection, the fluorescence signal was detected and photographed under a Zeiss LSM780 confocal microscope. The subcellular localization results showed that GbGELP was localized in the cell membrane ( Figure 4 b).

[0087] The subcellular localization of GhHDG2 was performed according to the subcellular localization method of GbGELP. The subcellular localization results showed that GhHDG2 was localized in the nucleus ( Figure 7 b).

[0088] Example 6 Phenotypic Identification of Transgenic Arabidopsis thaliana Ectopically Overexpressing GbGELP

[0089] In order to further clarify the function of GbGELP gene in plant growth and development, we selected PBI121 vector driven by cauliflower mosaic virus (CaMV) 35S promoter, developed recombination primers for BamHI and SacI restriction sites, and the forward and reverse primer sequences were SEQ ID NO.5 and SEQ ID NO.6, respectively. After cutting PBI121 vector with BamHI and SacI endonucleases, the CDS sequence of target gene GbGELP was fused by homologous recombination to construct expression vector for Arabidopsis transformation. Phenotypic investigation was conducted on three transgenic Arabidopsis lines (B2-1, B2-2, B2-4) overexpressing GbGELP ( Figure 4 a). Surface sterilized seeds were sown in rows on 1 / 2MS medium. The experiment was placed vertically in a growth chamber under long-day conditions (24 / 22℃, 16h light / 8h dark); after 7 days, the taproot cell length of wild-type (WT) and transgenic lines was observed under a Zeiss LSM780 confocal microscope, and the root cell length was measured by ImageJ software, and it was found that the root cells of the transgenic lines were longer ( Figure 4 cd); the main root lengths of wild type (WT) and transgenic lines were measured at the same time. The results showed that the transgenic lines showed longer main root lengths after 7 days of light culture ( Figure 4ef). In addition, surface-sterilized seeds were randomly sown on 1 / 2MS medium and placed horizontally in a growth chamber under long-day conditions (24 / 22°C, 16 h light / 8 h dark). After 10 days of growth, the wild type (WT) and transgenic lines were transferred to plastic cups filled with vermiculite (three plants per cup, two trays for each clone) and placed under short-day conditions (24 / 22°C, 8 h light / 16 h dark). The growth of rosette leaves of transgenic lines and WT was observed, and the transgenic lines showed more vigorous rosette leaves ( Figure 4 g). After 40 days, the wild type (WT) and transgenic lines began to bolt, and the main stems and leaves of the wild type (WT) and transgenic lines with uniform growth were selected to observe the number of epidermal hairs using a super-depth microscope (at least three biological replicates were used for each measurement). The transgenic lines showed more main stem epidermal hairs ( Figure 4 hi) and more leaf epidermal hairs ( Figure 4 jk). The experimental results showed that the transgenic Arabidopsis had longer roots, longer root cells, more vigorous rosette leaves, and more stem and leaf hairs, indicating that overexpression of GbGELP significantly promoted cell elongation, root length and growth potential of Arabidopsis plants.

[0090] Example 7 Identification of fiber phenotypes of plants with silenced GbGELP gene

[0091] In order to further clarify the role of GbGELP gene in cotton fiber development, we selected cotton leaf crinkle geminivirus vector CLCrV, selected SpeI and AscI restriction endonuclease sites, cloned 300bp of the GbGELP coding sequence into pCLCrVA vector (pCLCrV-GbGELP), the forward and reverse primer sequences were SEQ ID NO.7 and SEQ ID NO.8, respectively, and the specific sequence for silencing GbGELP was shown in SEQ ID NO.4. pCLCrVB was used as an auxiliary vector, pCLCrV-Su and pCLCrVA were mixed with pCLCrVB at a ratio of 1:1 and then infiltrated into the cotyledons of CSSL47 plants, respectively as positive control and negative control; pCLCrV-GbGELP was infiltrated in the same way as the experimental group. When yellow spots appeared on the leaves of the pCLCrV-Su positive control, 20 cotton plants inoculated with each combination were moved to large plastic pots and placed in a greenhouse (24 / 22℃, 16h light / 8h dark) until flowering. A sign with the date was hung on each flower, and cotton bolls at different developmental stages were subsequently sampled and phenotypes observed according to the date.

[0092] We collected fibers 10 days after flowering to test the silencing efficiency of GbGELP. The expression of GbGELP in pCLCrV-GbGELP plants was significantly reduced, and the bolls of pCLCrV-Su plants had obvious yellow spots, indicating that the silencing effect was good ( Figure 5 a). Fibers were collected at 15 days, 20 days and mature stage after flowering to measure fiber length. Fibers of pCLCrV-GbGELP plants at 15 days, 20 days and mature stage were significantly shorter ( Figure 5 b, c); we also used scanning electron microscopy to observe the protrusions of the fiber cells of the 0-day ovules. The protrusions on the surface of the 0-day ovules of the pCLCrV-GbGELP plants were significantly reduced ( Figure 5 d). The experimental results showed that compared with the control, the ovules of the plants with GbGELP silenced had significantly fewer protrusions and significantly shorter fibers, indicating that silencing GbGELP significantly inhibited fiber initiation and elongation.

[0093] Example 8 GhHDG2 promotes GbGELP expression by binding to the promoter HAHR1-box

[0094] In order to further clarify the difference in expression of marine and terrestrial alleles of GDSL-type esterase / lipase genes, we cloned the -2000bp promoter sequences of GbGELP gene from sea island cotton and GhGELP gene from upland cotton into pGreenII0800-LUC vector, selected HindIII and BamHI as restriction sites, and the forward and reverse primer sequences were SEQ ID NO.9 and SEQ ID NO.10, respectively. Through the analysis of PlantPAN database, a homeodomain-leucine zipper IV (HD-ZIP IV) binding element (HAHR1-box, 5'-CATTAAATT-3') was found at -520bp of GbGELP promoter, and there was an A / T SNP mutation in the element sequence in GhGELP promoter, resulting in the motif sequence of 5'-CATTTAATT-3' ( Figure 6 We analyzed the gene expression patterns of all HD-ZIP transcription factors in the cotton genome and found that GH_A13G1090 was highly expressed during the fiber elongation period and co-expressed with GhGELP ( Figure 7 a), the coding sequence of GH_A13G1090 is highly similar to Arabidopsis HOMEODOMAIN GLABROUS2 (AtHDG2), so it is named GhHDG2. Previous studies have shown that AtHDG2 plays a vital role in the development of Arabidopsis trichomes and can regulate cellulose biosynthesis (Marks et al. 2009; Kong et al. 2021). Subcellular localization showed that GhHDG2 is localized in the nucleus ( Figure 7 b).

[0095] In the luciferase experiment, we cloned the 60bp promoter fragment of HAHR1-box into the upstream of pGreenII 0800-LUC vector mini35S, and selected the restriction sites KpnI and HindIII; the obtained recombinant product (HAHR1-A-box-mini35S::LUC / HAHR1-T-mini35S::LUC) was used as the reporter factor, and the forward and reverse primer sequences were SEQ ID NO.11 and SEQ ID NO.12, respectively. 35S::GhHDG2 was used as the effector factor. The reporter factor and the effector factor were mixed in equal amounts and injected into tobacco leaves grown for 35 days. After 16 hours of dark treatment, they were grown under long-day conditions (24 / 22℃, 16h light / 8h dark) for 2 days, and the fluorescence signal was observed under a Tanon fluorescence colorimeter. Tobacco leaves infiltrated with only the reporter or co-infiltrated with the effector and HAHR1-T-mini35S::LUC reporter emitted weak fluorescence; tobacco leaves infiltrated with the effector and HAHR1-A-box-mini35S::LUC reporter emitted strong fluorescence ( Figure 7 c). The luminescence values ​​of LUC and REN were determined using a dual luciferase assay kit, and the promoter activity was expressed as the LUC / REN ratio: the LUC / REN ratio of tobacco leaves co-infiltrated with the effector and HAHR1-A-box-mini35S::LUC reporter and the effector and pGbGELP::LUC reporter was significantly higher ( Figure 7 d,e). In the GUS staining experiment, HindIII and BamHI restriction sites were selected for the GUS vector, and the forward and reverse primer sequences were SEQ ID NO.13-SEQ ID NO.16, respectively. The experimental method was the same as that of the LUC experiment. The results showed that GhHDG2 could bind to the GbGELP promoter ( Figure 7 f, g). In summary, GhHDG2 activates the transcription of GbGELP by binding to the HAHR1-box of the GbGELP promoter.

[0096] Based on the above results, this study used linkage analysis and permutation mapping methods to identify a fiber fineness QTL (qFM-A11) in a marine-continental introgression material CSSL47 of high-quality fiber. Combined with the differential expression of genes in the candidate interval at different fiber development stages, a GDSL-type esterase / lipase gene GbGELP was found to be a candidate gene for this QTL. This gene was highly expressed in different fiber development stages of CSSL47, and the expression level was highest in 15-day-old fibers. CDS sequence analysis of the GDSL-type esterase / lipase gene in CSSL47 and TM-1 showed that there were two non-synonymous SNP mutations in this gene. Compared with TM-1, CSSL47 has advantages in fiber length, fiber strength, and fiber fineness. The fiber of CSSL47 plants with GbGELP silenced is shorter, and there are fewer fiber cell protrusions on the surface of the ovule on the day of flowering. The root length, root cell length, rosette leaf growth, and leaf and stem hair numbers of Arabidopsis plants heterologously expressing GbGELP are better than those of the control plants. Further studies have found that a transcription factor GhHDG2 promotes its transcription by binding to the GbGELP promoter HAHR1-box. The study shows that GbGELP plays an important role and has application prospects in improving cotton fiber quality traits and breeding new high-fiber quality cotton varieties.

[0097] SEQ ID NO.1 (CDS sequence of GbGELP (GB_A11G1593)) 1068

[0099] Gossypium barbadense

[0100] ATGGAATTGAAGCAAATGGCGCCATCGATACACATCTTATGGCTCCTTTCAATTCAATT

[0101] TTTGGTGTTGGTTAATGGGGGCAAAATTCCAGCAATCATAGTGTTCGGGGACTCCTCA

[0102] GTTGATTCTGGGAATAACAACTACATCCCCACCGTAGCTAGGAGCAATTTTCAACCTT

[0103] ATGGTCGAGACTTCAACGGTAGGCGTCCAACGGGAAGATTTTCCAATGGCAAAATCA

[0104] CAACCGACTTCATCTCCGAGGCTTTCGGCCTCAAACCGGCAATTCCTGCTTACCTCGA

[0105] TCCTTCCTATAGTATATCCGATTTCGCCACCGGGGTTACCTTTGCTTCTGCCGCAACCG

[0106] GCTACGACAATGCCACTTCCAATGTCCTCTCAGTGATACCACTATGGAAACAACTGGA

[0107] GTACTACAAGAACTATCAAAAGAAACTGAGAGCCTATCTGGGAGATAGGAAAGCCAA

[0108] CGGCGTAATCAGCGGGGCTTTATACCTGATAAGCGTGGGAACGAACGATTTCCTGGA

[0109] GAACTATTACGCAATCCCAGGCCGTTCATCGGAATACACCATCGAAGAATACGAAAGC

[0110] TTCCTGGTTGGGATCGCCGCAAGTTTCACAGAGAAGCTGTATGAACTTGGAGCCCGG

[0111] AAGATATCGTTAGGAGGGCTGCCTCCGATGGGGTGTATGCCGTTGGAGAGAACCGGG

[0112] AACCTTATGGGTGGAAGCGAGTGTGTAGATAGTTTCAACAATTTGGCAGCCGATTTCA

[0113] ATGGGAAACTGAATGCTTTAGTGATTAAACAGAATAAAAAGTTTCATGGAATGCAGAT

[0114] GGTGTTTTCAGATCCCTATGGTATTTTGATAAAAATCATTCAAAAGCCTGCAGTTTATG

[0115] GGTTCGAGGTAACGGCGGTGGCATGTTGTGCAACAGGGATGTTCGAAATGGGATACG

[0116] CATGCAGCCGGAGAAATCCTTTTACATGTTCCAATGCCGACGAGTTTGTGTTTTGGGA

[0117] TTCTTTTCACCCCACTCAGAAAACCTGTTCTATCATAGCCACTTACATTGTCCAAAATG

[0118] CTTTGGCCAAGTTCCTTTCACTTTAASEQ ID NO.2 (Amino acid sequence of GbGELP (GB_A11G1593)) 355

[0120] Gossypium barbadense

[0121] MELKQMAPSIHILWLLSIQFLVLVNGGKIPAIIVFGDSSVDSGNNNYIPTVARSNFQPYGRD

[0122] FNGRRPTGRFSNGKITTDFISEAFGLKPAIPAYLDPSYSISDFATGVTFASAATGYDNATSN

[0123] VLSVIPLWKQLEYYKNYQKKLRAYLGDRKANGVISGALYLISVGTNDFLENYYAIPGRSS

[0124] EYTIEEYESFLVGIAASFTEKLYELGARKISLGGLPPMGCMPLERTGNLMGGSECVDSFN

[0125] NLAADFNGKLNALVIKQNKKFHGMQMVFSDPYGILIKIIQKPAVYGFEVTAVACCATGMF

[0126] EMGYACSRRNPFTCSNADEFVFWDSFHPTQKTCSIIATYIVQNALAKFLSLSEQ ID NO.3 (Promoter sequence of GbGELP (GB_A11G1593)) 2001

[0128] Gossypium barbadense

[0129] TTTACTATAGTATCCATCCTTAATGGTGAAAAAAAAATAAAGAAGGTAATTATATAATG

[0130] AACACATGATATAGAAATTAATCCCTATCAACATATTACTTAGTTTAATGAAAAA

[0131] GAATTTTGTTGATGTAAGTGTTGTTAAAATAGAATCCGAATTAATAAATCAAATCGATATA

[0132] TTGATCTAAACAAAAGATTTGAATAACCCACTAAACAACCACTCAAAACTAATAAA

[0133] AAAAACCCAAAATGAACACAAAACAAACAATTAAGTCCATTTATATTTTTTTCATA

[0134] GTTAAACCAATTAATCTGACAACTGATATAAACTCTACATTAAGTTCAATATCCAAATT

[0135] TCGACAAAGGTCCCAATGGTAGAGTAAAAACCTTGTAATTGAATTGATTGTCGCAAA

[0136] GGGATATACCAATTAATGTGGTTGAGGACCAAAAAGAAATTCATAGAAAAAATAATA

[0137] AATGAGGGTTAGTTGCAGGTAAAGCACCACCTTTCTAGTTGGGAAAGCCCTTCCAA

[0138] TTCAAGGCCTTGACCTACACACCAACGACTTGCATGTGTTTCTACTAATAACACCACC

[0139] AATAATAAATCTCTCTCCACATTTTTTTTCTTTTAGATAATCTGAATTATTTCCCCACA

[0140] TTTTAATTTAAGTAGTCCGTATGCTTTACGGGTTTAGTTGATTGCTTTTGCTATTAATTTT

[0141] AATGATGCCTTTATTAATTTCAAATTTTCAATAATTAATTTAAAAATGTAAT

[0142] GCTTCTACTCCAAATCTTAATTCGGTTTGAATCAATAAGTCATCAAAATAAATTTTGT

[0143] TATTATTAAATTATTATCGTATTGTTGATGGAGTTTAATTTCACAAGTTAAACC

[0144] ATCATGTATCTTTTTTTTAAATATAATTAAGGACGCTAACTGTTTTTTAATCAATTA

[0145] AAAAAATTTTATTGTACATAAATTTAAGTAAAATCTCAATTAGATAAATTGG

[0146] TCTAATGTATTATTTAACATGCAACTTTTTTTTTTTTTTAAAAAAATTGG

[0147] TTTGATCCATTTCTCACAAATTGTTAACATTATTGATATATAGGTAAATATTATT

[0148] ATTACKAAAGTTGATGACGTTATTCATCAAAGAATGACGCCACATEMENT

[0149] GCCACGTTAGCTACCAGAATAAAAAAAATTTTTTTGTGGTGCCAAGGAGAAATAAT

[0150] AGTATTTTCCTAATTTATTAAGTTGAACCATTCTCCTTGGCACCACTAAAAAATTAAT

[0151] TTTTTATTCCAGTGGCTGACATGACATGTTGGTAGTACCATTCTCTTTAGCTTCGTCA

[0152] ATTTTTATTGTTAATTTCAAGTCATTTATGTATAATAAAAAAATAGGTCATTTTTTT

[0153] AATTAATCAAGATTTTAAAATTATCTATATAAAAAATCTAAATAACACATTAAATTAAAA

[0154] TTAATGTATTATTAATTTATCTTTAAATTTAATAGCTTGTATTTATGAAAGACATTAAAAA

[0155] GCTTTAATTATGATACAGGACTTAGCTAAAGCCTGAAGCAATAAGAACCATTGTCTCA

[0156] AATGTTTGGACGTCTTTAGCCAACCTGGCCGTTATTACATCACCCAAGAACAGCGCTT

[0157] ACTCCTGATTCAAGTAGCTATTAAATCTTTCACCAACATTCCATCTTAATTATTATATATA

[0158] TATATTTTTTGGAATATATATTACCATATCATAGTTACATACAATTATAGTGTTTTGTATTT

[0159] ATATAAAATTTTAACATTTTATTTATTATTATCATTTTCTGTGTCAGCTTGTCAGGTCGCA

[0160] TCATACTAATATTTACGCATATAAAAGCCCTCCTCCAACCATTTGATCATCCGAAAGTT

[0161] AGAAAATAAGAAATAAGAAAGTTAGCTCGATCCCTCCCCTCCCCACCCCTACCACATT

[0162] TGTATATATATATATATATATAGTCTGTTTGAAAATCTASEQ ID NO.4(Specialized sequence for silencing GbGELP (GB_A11G1593)) 300

[0164] CTCTCAGTGATACCACTATGGAAACAACTGGAGTACTACAAGAACTATCAAAAGAAA

[0165] CTGAGAGCCTATCTGGGAGATAGGAAAGCCAACGGCGTAATCAGCGGGGCTTTATAC

[0166] CTGATAAGCGTGGGAACGAACGATTTCCTGGAGAACTATTACGCAATCCCAGGCCGT

[0167] TCATCGGAATACACCATCGAAGAATACGAAAGCTTCCTGGTTGGGATCGCCGCAAGTT

[0168] TCACAGAGAAGCTGTATGAACTTGGAGCCCGGAAGATATCGTTAGGAGGGCTGCCTC

[0169] CGATGGGGTGTATGSEQ ID NO.5 (forward primer sequence for constructing GbGELP overexpression vector using PBI121 vector) 42

[0171] ACGGGGGACTCTAGAGGATCCATGGAATTGAAGCAAATGGCG

[0172] SEQ ID NO.6 (reverse primer sequence for constructing GbGELP overexpression vector using PBI121 vector) 44

[0174] CGATCGGGGAAATTCGAGCTCTTAAAGTGAAAGGAACTTGGCCA

[0175] SEQ ID NO.7 (Forward primer sequence for constructing GbGELPCLCrV silencing vector) 48

[0177] ATGGCATGCCTGCAGACTAGTCTCTCAGTGATACCACTATGGAAACAA

[0178] SEQ ID NO.8 (reverse primer sequence for constructing GbGELPCLCrV silencing vector) 42

[0180] TTCACTAGACCTAGGGGCGCGCCCATACACCCCATCGGAGGC

[0181] SEQ ID NO.9 (Forward primer sequence for constructing GbGELPpGreenII 0800-LUC vector) 51

[0183] GTCGACGGTATCGATAAGCTTTTTACTATAGTATCCATCCTTAATGGTGAA

[0184] SEQ ID NO.10 (reverse primer sequence for constructing GbGELPpGreenII 0800-LUC vector) 63

[0186] CGCTCTAGAACTAGTGGATCCTAGATTTTCAAACAGACTATATATATATATATATATACA

[0187] AAT

[0188] SEQ ID NO.11 (Forward primer sequence for constructing GbGELPpGreenII 0800-LUC (mini35S) vector) 58

[0190] CTATAGGGCGAATTGGGTACCTTTAATTAATCAAGATTTTAAAATTATCTATATAAAA SEQ ID NO.12 (reverse primer sequence for constructing GbGELPpGreenII 0800-LUC (mini35S) vector) 52

[0192] ATATAGAGGAAGGGTAAGCTTTTTTTAATGTCTTTCATAAATACAAGCTATT

[0193] SEQ ID NO.13 (Forward primer sequence for constructing GbGELPGUS (mini35S) vector) 59

[0195] GACCATGATTACGCCAAGCTTTATCTATATAAAAAATCTAAATAACACATTAAATTAAA

[0196] SEQ ID NO.14 (reverse primer sequence for constructing GbGELPGUS (mini35S) vector) 58

[0198] ATATAGAGGAAGGGTGGATCCGATAAATTAATAATACATTAATTTTAATTTAATGTGT SEQ ID NO.15 (forward primer sequence for constructing GhGELPGUS (mini35S) vector) 59

[0200] GACCATGATTACGCCAAGCTTTATCTATATAAAAAATCTAAATAACACATTTAATTAAA

[0201] SEQ ID NO.16 (reverse primer sequence for constructing GhGELPGUS (mini35S) vector) 58

[0203] ATATAGAGGAAGGGTGGATCCGATAAATTAATAATACATTAATTTTAATTAAATGTGT.

Claims

1. Use of the GbGELP gene as shown in SEQ ID NO.1 or a biological material related to the GbGELP gene in the following (a1) or (a2) or (a3) ​​or (a4): (a1) improving the quality traits of cotton fiber, or preparing products for improving the quality traits of cotton fiber; (a2) improving the quality of cotton fibers, or preparing products for improving the quality of cotton fibers; (a3) cultivating new high-quality cotton fiber germplasm, or preparing products for cultivating new high-quality cotton fiber germplasm; (a4)) Promote plant growth.

2. The use according to claim 1, characterized in that: The biological material related to the GbGELP gene is the biological material described in (b1) or (b2) or (b3) below: (b1) protein GbGELP encoded by the GbGELP gene; (b2) primers for amplifying the full-length coding sequence of the GbGELP gene; (b3) Biological material containing the GbGELP gene.

3. The use according to claim 2, characterized in that: The protein GbGELP encoded by the GbGELP gene in (b1) has an amino acid sequence as shown in SEQ ID NO.

2.

4. The use according to claim 2, characterized in that: The primers used to amplify the full-length coding sequence of the GbGELP gene in (b2) are shown as SEQ ID NO.5 and SEQ ID NO.

6.

5. The use according to claim 2, characterized in that: The biological material containing the GbGELP gene described in (b3) is at least one of the following (c1) to (c9): (c1) an expression cassette containing the GbGELP gene; (c2) a recombinant vector containing the GbGELP gene, or a recombinant vector containing the expression cassette described in (c1); (c3) a recombinant microorganism containing the GbGELP gene, or a recombinant microorganism containing the expression cassette described in (c1), or a recombinant microorganism containing the recombinant vector described in (c2); (c4) a transgenic plant cell line containing the GbGELP gene, or a transgenic plant cell line containing the expression cassette of (c1), or a transgenic plant cell line containing the recombinant vector of (c2); (c5) transgenic plant tissue containing the GbGELP gene, or transgenic plant tissue containing the expression cassette described in (c1), or transgenic plant tissue containing the recombinant vector described in (c2); (c6) a transgenic plant organ containing the GbGELP gene, or a transgenic plant organ containing the expression cassette described in (c1), or a transgenic plant organ containing the recombinant vector described in (c2); (c7) a transgenic plant containing the GbGELP gene, or a transgenic plant containing the expression cassette described in (c1), or a transgenic plant containing the recombinant vector described in (c2); (c8) tissue cultures produced from regenerable cells of the transgenic plant described in (c7); (c9) Protoplasts produced from the tissue culture described in (c8).

6. The use according to claim 1, characterized in that: The GbGELP gene is used as a target gene and overexpressed through genetic engineering methods to improve cotton fiber quality traits, improve cotton fiber quality, cultivate new cotton high-quality fiber germplasm or promote the growth of target plants.

7. The use according to claim 1 or 6, characterized in that: The plant is cotton or Arabidopsis thaliana.

8. A method for improving the quality traits of cotton fiber or enhancing the quality of cotton fiber, characterized in that: Overexpression of the GbGELP gene with a nucleotide sequence such as that shown in SEQ ID NO. 1 in cotton improves cotton fiber quality traits or increases cotton fiber quality.

9. A GbGELP gene related to cotton fiber quality traits, the gene having a nucleotide sequence as shown in SEQ ID NO.

1.

10. The biological material related to the GbGELP gene according to claim 9, characterized in that: The biological material is the biological material described in (d1) or (d2) or (d3) below: (d1) a protein GbGELP encoded by the GbGELP gene having an amino acid sequence as shown in SEQ ID NO.2; (d2) primers as shown in SEQ ID NO.5 and SEQ ID NO.6 for amplifying the full-length coding sequence of the GbGELP gene; (d3) An expression cassette, recombinant vector, transgenic cell line or recombinant bacteria containing the GbGELP gene.

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