Application, method and recombinant vector of caham gene and its encoded protein in pepper lateral branch regulation

Abstract

The application belongs to the technical field of plant molecular biology, and discloses application and method of CaHAM gene or CaHAM protein in pepper lateral branch regulation and a recombinant vector, wherein the nucleotide sequence of the CaHAM gene is shown as SEQ ID NO:1, and the amino acid sequence of the CaHAM protein is shown as SEQ ID NO:2. The pepper CaHAM gene is successfully identified and functionally verified, and its biological function of positively regulating lateral branch elongation in the pepper is first disclosed. The finding fills the blank of function research of the HAM gene family in the pepper, an important crop, provides a brand-new and definite gene target for understanding and improving the pepper plant type from a molecular level, lays a foundation for cultivating a new pepper variety with short lateral branches, and further improves the efficiency of mechanical harvesting of the pepper and realizes mechanical cultivation.

Description

Technical Field

[0001] This invention belongs to the field of plant molecular biology technology, and in particular relates to the application, method and recombinant vector of a CaHAM protein and its encoded protein in the regulation of lateral branches in pepper. Background Technology

[0002] Chili peppers are an important vegetable crop globally, and their standardized production urgently needs to achieve high yields and mechanized harvesting through genetic improvement of plant type. Lateral branches, as a core trait of plant type, directly affect light energy utilization efficiency and suitability for mechanized harvesting due to their spatial distribution and quantity. Traditional manual pruning methods are time-consuming, labor-intensive, and costly; therefore, breeding ideal chili pepper plant types is an effective way to achieve high yields and mechanized harvesting suitability. However, the key genes and molecular mechanisms regulating lateral bud development remain unclear.

[0003] In model plants, the GRAS family transcription factor HAM (HAIRY MERISTEM) has been confirmed as a core factor regulating the homeostasis of shoot apical meristem (SAM) and axillary bud meristem (AM). The HAM (HAIRY MERISTEM) protein was first identified in ornamental morning glory, and its function was first elucidated, clarifying its role as a GRAS family transcription factor. family transcription factors, non-cellular autonomously from L3 The source tissue sends differentiation-inhibiting signals to the meristem, maintaining the undifferentiated state of the shoot apical meristem (SAM) and lateral buds. Subsequently, the HAM was proposed in Arabidopsis. WUS CLV3 ternary regulatory circuit: HAM protein can directly form a complex with WUS protein, inhibiting... CLV3 Transcription, thereby blocking the CLV3-mediated negative feedback inhibition of stem cells, keeps SAM in an open state. Furthermore, the cross-species functional conservation and plasticity of the HAM gene were further demonstrated in tomato. SIHAM High expression of HAM genes in SAM and compound leaf primordia, with deletion leading to meristem instability and abnormal compound leaf morphology, has been confirmed to be negatively regulated by miR171. Furthermore, HAM genes (especially Type II members HAM1-3) are indispensable for maintaining the undifferentiated state of SAM and axillary bud meristem (AM); their deletion results in early termination of the main stem, inhibited axillary bud development, and consequently a significant reduction in the number of lateral branches. Although significant progress has been made in the study of HAM genes, the conservation of their function in peppers and their interaction mechanisms with other regulatory networks remain poorly understood, thus necessitating further in-depth research on these genes.

[0004] In summary, current technologies have not yet provided a clear molecular target and its application scheme for directly and efficiently improving the lateral branch length of chili peppers through genetic means to meet the urgent needs of mechanized harvesting. Therefore, identifying the key genes regulating lateral branch elongation in chili peppers, elucidating their functions, and developing their application methods in the breeding of new varieties have significant theoretical and practical value. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the background art above, and to provide an application, method and recombinant vector of the CaHAM gene and its encoded protein in the regulation of lateral branches of pepper.

[0006] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows:

[0007] The application of the CaHAM gene or CaHAM protein in the regulation of lateral branches in pepper, wherein the nucleotide sequence of the CaHAM gene is shown in SEQ ID NO: 1, and the amino acid sequence of the CaHAM protein is shown in SEQ ID NO: 2.

[0008] Nucleotide sequence: amino acid sequence: MIVIPQGNSIPAKGVLCVSNFVPSITSSSSSSQEAPIFMKDANFTRNEPVSELDTRSPSPSASSSSCSYGGNTAVPGAGSWKTDGKKEELVMELQPLTVGSDPEKSVLGFGDLDNLLPEFVGSDQSFLRWISGDVEDPSVSLKQLLNGDFGSGFEVSGTGSLVHTDANLSFSG SNICLNANIERFGTVIDSNNGRNNNSFEKNLNVNPYLEQKPQVMANQNQFQNAVCVNILGSSPCDINQEQPLSKRHNSGALVSSLGLLPKVPFFDASCDFLMRKQPLGQMQQQVNLLPAQQFQPKPLIVPKLEAAGGGGNGNLMVPRHQLQEQQFIYDQIFQASELLLAGQF SNAQLILARLNQQLSPIGKPSRRAAFYIKEALQLPFLVPCTTSTFLPPRSPTPFDCVLKMDAYKSFSEISPLIQFMNFTSNQAILEALGDAEQIHIIDFDIGFGAQWSSFMQELPSSSRKATYLKITAFASPSTHHSVEIGIMHESLTQFANDAGMRFELEVINLDSFDPKSYP LSSLRSSECEAIAINFPIWSISSLPFAFPSLLHCMRQLSPKVVVSLECGCERTELPLKHHLLHALQYYETLLASIDAANLTPDIAKKIERSLLQPSIENMILGRLRSPDRMPPWRNLFTSAGFSPIAFSNMTEVQAECVVKRTHVGGFHVEKRQTSLVLCWKQQELLSAATWRC The above-described application, preferably, involves reducing or inhibiting the expression of the CaHAM gene, or reducing or inhibiting the activity of the CaHAM protein, to obtain pepper plants with shortened lateral branches.

[0009] Based on a general inventive concept, the present invention also provides the application of a recombinant vector in the cultivation of short lateral branch pepper plants, wherein the recombinant vector contains a nucleotide fragment capable of reducing or inhibiting the expression of the endogenous CaHAM gene in pepper plants, the nucleotide sequence of the CaHAM gene is shown in SEQ ID NO: 1, and the amino acid sequence of the protein it encodes is shown in SEQ ID NO: 2.

[0010] In the above applications, preferably, the recombinant vector is a virus-induced gene silencing vector. More preferably, the vector is a VIGS vector (pTRV2e-CaHAM-CMV2b) that silences the CaHAM gene.

[0011] In the above application, preferably, the nucleotide fragment expressed by the endogenous CaHAM gene in the chili plant is a specific fragment of the CaHAM gene, and its nucleotide sequence is shown in SEQ ID NO: 3: CAAATGCAGCAACAAGTCAATTTGCTGCCTGCTCAACAGTTTCAGCCGAAGCCATTAATTGTACCTAAGCTTGAGGCAGCTGGTGGTGGTGGTAATGGTAATTTGATGGTGCCTCGTCATCAACTGCAGGAACAACAATTTATTTATGAC CAGATTTTTCAGGCCTCAGAACTATTGCTGGCCGGACAATTCTCAAACGCGCAATTGATATTGGCGCGGCTCAATCAACAGCTTTTCCCATTGGGAAACCCTCAAGGAGGGCTGCTTTTTATATCAAGGAGGCTCTGCAGTTGCCTTTC.

[0012] Based on a general inventive concept, the present invention also provides a method for cultivating pepper plants with shortened lateral branches, wherein the expression of the CaHAM gene is reduced or inhibited in the pepper plant, or the activity of the CaHAM protein is reduced or inhibited to obtain pepper plants with shortened lateral branches; wherein the nucleotide sequence of the CaHAM gene is shown in SEQ ID NO: 1, and the amino acid sequence of the CaHAM protein is shown in SEQ ID NO: 2.

[0013] The above-described method, preferably, achieves the reduction or inhibition by introducing the recombinant vector described above into the pepper plant.

[0014] The above-described method, preferably, achieves the reduction or inhibition by knocking out or silencing the CaHAM gene using gene editing technology.

[0015] Based on a general inventive concept, the present invention also provides a recombinant vector comprising a VIGS vector backbone for inducing gene silencing and an insert fragment, the nucleotide sequence of which is shown in SEQ ID NO: 3.

[0016] Preferably, the VIGS vector backbone is the pTRV2e-CMV2b vector; the insert fragment is cloned into the SamI restriction site of the pTRV2e-CMV2b vector.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention successfully identified and functionally verified the CaHAM gene in chili pepper, revealing for the first time its biological function in positively regulating lateral branch elongation in chili pepper. This discovery fills the gap in the functional study of the HAM gene family in chili pepper, an important crop, and provides a new and clear gene target for improving chili pepper plant architecture at the molecular level. It lays the foundation for breeding new chili pepper varieties with short lateral branches, thereby improving the efficiency of mechanized harvesting of chili pepper and realizing mechanized cultivation.

[0018] (2) By constructing a VIGS vector that specifically silences the CaHAM gene and using Agrobacterium-mediated transformation, this invention successfully created pepper plants with significantly shortened lateral branches. This provides an efficient and reproducible technical means to quickly obtain germplasm resources with short lateral branches without relying on traditional hybridization. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 The phylogenetic tree of the CaHAM gene family was constructed using the NJ method of MEGA11 in this embodiment of the invention.

[0021] Figure 2 Real-time quantitative PCR (RT-qPCR) analysis of CaHAM and its most closely related gene CaGRAS5 in the phylogenetic tree, and subcellular localization of CaHAM are shown in the embodiments of this invention: A is the RT-qPCR analysis of CaHAM and CaGRAS5; B is the subcellular localization of CaHAM.

[0022] Figure 3 The following are examples of pepper phenotypes and verifications for silencing the CaHAM gene in this invention: A shows the pepper phenotype with the CaHAM gene silenced; B shows the changes in TRV2-specific primers in silent plants for TRV2-empty vector, TRV2:PDS, CK, and TRV2:CaHAM; C shows an RT-qPCR image verifying the decrease in CaHAM gene expression after silencing; D shows the axillary bud length statistics in CaHAM-silenced plants, where 'th' represents the internode number. This means p ≤ 0.01; This means p ≤ 0.001. Detailed Implementation

[0023] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0024] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0025] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0026] Example 1: Phylogenetic analysis of the pepper GRAS gene family and preliminary identification of CaHAM (1) Phylogenetic analysis of the GRAS gene family in chili pepper This embodiment aims to identify genes in chili peppers that are homologous to AtHAM in Arabidopsis thaliana using bioinformatics methods.

[0027] Gene family member acquisition and screening: Using 33 known GRAS protein sequences from Arabidopsis thaliana as query sequences, local Blast homology alignment of the pepper genome was performed using TBtools software. After preliminary screening to obtain candidate sequences, domain verification was performed using Pfam and NCBI-CDD online tools to ensure that they contained the typical GRAS domain (PF03514), thus obtaining candidate genes for the pepper GRAS family.

[0028] Phylogenetic tree construction: To clarify the phylogenetic relationships within the pepper GRAS family, after removing atypical members with an amino acid length of less than 350, multiple sequence alignment of GRAS protein sequences of pepper, tomato, and Arabidopsis was performed using MEGA11 software, and a phylogenetic tree was constructed using the neighbor-joining method with a bootstrap value set to 1000 replicates.

[0029] Results Analysis: Phylogenetic analysis of the GRAS protein sequences of pepper, tomato, and Arabidopsis thaliana, and referring to the established classification criteria of Arabidopsis thaliana, members of the pepper GRAS family were divided into different evolutionary subfamilies, such as LAS, SHR, SCL3, SCR, PAT1, CaGRAS, HAM, DELLA, SCL8, and Others. Figure 1As shown in the figure, the pepper gene numbered Caz01g05750 (named CaHAM) and the CaGRAS5 gene are closely related to the Arabidopsis thaliana AtHAM homolog and belong to the HAM subfamily.

[0030] (2) Cloning and sequence analysis of the CaHAM gene The four-leaf, one-heart pepper material 'Zhangshugang S8' used in this embodiment (preserved at the Germplasm Center of the College of Horticulture, Hunan Agricultural University, and guaranteed for sale for at least 20 years; the applicant disclosed this germplasm resource in the journal Journal of Horticulture in the article "Study on Fruit Quality Characteristics of Fresh-Eating Young Pepper 'Zhangshugang'") was used to extract RNA from the lateral buds using the EasyPure® Plant RNA Kit. The procedure was followed according to the kit instructions. The RNA content and quality of the extracted RNA were detected using a micro spectrophotometer. The RNA was reverse transcribed into cDNA using the RevertAid First Strand cDNA Synthesis Kit (Thermo Scientific, China), and the reverse transcription product was used for subsequent PCR.

[0031] Approximately 1000 ng of cDNA was used as a template for PCR amplification of the CaHAM gene. The upstream and downstream primers were SEQ ID NO: 4 (5'-ATGATTGTAATACCTCAAGGAAATAGCATACC-3') and SEQ ID NO: 5 (5'-TTAACACCTCCAAGTAGCAGCT-3'), respectively. Amplification was performed using 2×Phanta Max Master Mix (Novazia, Nanjing). The PCR reaction system (50 μL) consisted of: 25 μL of 2×Phanta Max Master Mix, 2 μL each of the upstream and downstream primers, 2 μL of cDNA, and 2 μL of ddH2O. The reaction program was: 95 ℃, 3 min; 95 ℃, 15 sec, 58 ℃, 15 sec, 72 ℃, 1 min, 35 cycles; 72 ℃, 5 min.

[0032] The PCR product of the CaHAM gene was purified and cloned into the pCE2 TA / Blunt-Zero Vector (Novozymes, Nanjing) to construct the recombinant plasmid T-CaHAM. This plasmid was transformed into *E. coli* DH5α competent cells, and sequencing verification by Youkang Biotechnology Co., Ltd. confirmed that the nucleotide sequence of the CaHAM gene is shown in SEQ ID No:1, and its encoded amino acid sequence is shown in SEQ ID No:2.

[0033] Example 2: Expression pattern analysis and subcellular localization of the CaHAM gene This embodiment aims to verify the expression characteristics of the CaHAM gene and the cellular localization of its encoded protein.

[0034] 1. Plant material and RNA extraction: Six tissue parts of the pepper variety 'Zhangshugang S8', namely roots, stems, leaves, flowers, axillary buds and growing points, were collected 35 days after sowing. Total RNA was extracted and reverse transcribed into cDNA using the reverse transcription kit described above.

[0035] 2. Real-time quantitative PCR analysis: Using cDNA as a template, a 2×ChamQ Universal SYBR qPCRMaster Mix (Vazyme, China) kit was used. The instrument was a LightCycler® 96 real-time quantitative PCR system. The reaction volume was 20µL, and the program was as follows: 95℃ pre-denaturation for 30 s, 95℃ pre-denaturation for 10 s, 60℃ pre-denaturation for 30 s, for more than 40 cycles, followed by 95℃ pre-denaturation for 15 s, 60℃ pre-denaturation for 60 s, and 95℃ pre-denaturation for 15 s. CaActin was used as the internal control gene. The primers used are shown in Table 1.

[0036] Table 1 lists the names and sequences of the primers used.

[0037] 3. Expression pattern results: such as Figure 2 As shown in Figure A, the expression level of the CaHAM gene in lateral buds and shoot tips was significantly higher than that of CaGRAS5, suggesting that CaHAM may be involved in the developmental regulation of pepper meristems.

[0038] 4. Subcellular localization vector construction: Using pSuper1300-eGFP as the vector backbone, the CDS sequence of the CaHAM gene was obtained by PCR amplification, and Hind III and Kpn I homologous arms were introduced at both ends. The purified gene fragment was ligated with the vector that had undergone the same double enzyme digestion to construct the recombinant plasmid pSuper1300-CaHAM-eGFP. After confirmation by sequencing, it was transformed into Agrobacterium GV3101 competent cells using the freeze-thaw method. The specific process is as follows: (1) Gene fragment acquisition: The CDS sequence of the gene CaHAM was obtained by PCR amplification, and the homologous arms of Hind III and Kpn I were introduced at its 5' and 3' ends, respectively.

[0039] (2) Double digestion: The purified gene CaHAM fragment and the pSuper1300-eGFP empty vector plasmid were subjected to double digestion using Hind III and Kpn I restriction enzymes, respectively.

[0040] (3) Ligation and transformation: The CaHAM gene fragment, which was digested and purified by enzymes, was homologously recombinated with the vector backbone using ligase at 50°C. The ligation product was then transformed into competent DH5α cells.

[0041] (4) Positive clones were screened on plates containing Kan antibiotics, and PCR and enzyme digestion were performed for identification. The plasmids that were verified to be correct were sequenced to ensure that CaHAM was correctly inserted into the vector to form a fusion gene. Finally, the recombinant plasmid was obtained and named pSuper1300-CaHAM-eGFP.

[0042] (5) Transformation of Agrobacterium: The above-verified recombinant plasmid pSuper1300-CaHAM-eGFP was transformed into Agrobacterium competent cells GV3101 by freeze-thaw method.

[0043] (6) Bacterial culture and preparation: Select positive Agrobacterium colonies and culture them in LB liquid medium containing antibiotics Kan (50 mg / ml) + Rif (25 mg / ml) until the logarithmic growth phase. Collect the bacterial cells by centrifugation and resuspend them in injection buffer (10 mM MMES, 10 mM MgCl2, 150 μM acetylsyl syringone, pH 5.6) to a concentration of OD600≈0.8-1.0.

[0044] 5. Subcellular localization observation: Healthy 5-week-old Nicotiana benthamiana species were selected. Nicotiana benthamiana Leaflets were treated with a sterile syringe (needle removed) to inject bacterial suspension into the intercellular spaces beneath the epidermis on the underside of the leaf. The cells were then incubated for 60 hours under suitable light and temperature (25°C). Fluorescence signals in the injected areas were observed using a laser confocal microscope (LSM800, Zeiss, Jena, Germany). Figure 2 As shown in Figure B, by comparing the colocalization of the eGFP fluorescence signal and the fluorescence signal of the nuclear marker HY5-mCherry, it was determined that the protein encoded by the CaHAM gene is located in the nucleus of plant cells.

[0045] Example 3: Silencing the CaHAM gene using VIGS technology and its functional verification In this embodiment, the pTRV2e-CaHAM-CMV2b vector was constructed using virus-induced gene silencing technology (VIGS) to silence genes in pepper and to verify the function of the CaHAM gene in the development of lateral branches in pepper in vivo.

[0046] 1. Construction of VIGS silencing vector: (1) A specific fragment of CaHAM (300 bp in length) was obtained using the VIGS Tool based on the Solanaceae database (Sol Genomics Network). The nucleotide sequence of this specific fragment is shown in SEQ ID NO:3, corresponding to nucleotides 846 to 1146 in SEQ ID NO:1.

[0047] (2) Using cDNA from the lateral buds of the Zhangshugang S8 variety as a template, the specific fragment was amplified using the PCR system and procedure shown in Table 2, through primers (CaHAM-VIGS-F / R) containing homologous arms of the SamI restriction site. The primers used are as follows (as shown in SEQ ID NO: 14 and SEQ ID NO: 15): CaHAM-VIGS-F: 5'-TGAGGAGAAGAGCCCATGATTGTAATACCTCAAGGAAATAGCATACCAG-3'; CaHAM-VIGS-R: 5'-GCTCGACGACAAGACCCCCCCACAGTTAATGGCTGC-3'.

[0048] The PCR reaction system for amplification is as follows: Table 250 μL PCR reaction system

[0049] Reaction program: 95℃ for 3 min; 95℃ for 15 sec, 58℃ for 15 sec, 72℃ for 30 sec, 35 cycles; 72℃ for 5 min.

[0050] (3) The empty vector pTRV2e-CMV2b (CMV2b element restriction endonuclease insertion method) was linearized by digestion with SamI restriction enzyme. After digestion, the linear vector was recovered using the Novizan gel recovery kit. The digestion system of Thermo Fisher Scientific was as follows: 5 μL of 10×FastDigest Buffer, 1 μL of SamI enzyme, 1000 ng of pTRV2e-CMV2b vector plasmid, and water was added to make up to 50 μL; reaction program: 37℃, 3h.

[0051] (4) The linear fragment and the enzyme-digested vector were homologously recombinated at 50°C for 15 min using the Uniclone OneStep Seamless Cloning Kit of Jinsha Biotechnology to construct the recombinant vector pTRV2e-CaHAM-CMV2b. Subsequently, it was transformed into Escherichia coli DH5α. After the sequencing was correct, it was transformed into Agrobacterium GV3101. The colonies with correct single-clone sequencing were added to an equal volume of 50% glycerol and stored at -80°C.

[0052] (5) Mix the Agrobacterium tumefaciens bacterial suspension containing the pTRV1 helper vector with bacterial suspension containing pTRV2e-CaHAM-CMV2b (experimental group) or empty vector pTRV2e-CMV2b (control group) at a ratio of 1:1, adjust the OD600 to about 0.8, and let stand at room temperature for 2 hours.

[0053] The mixed bacterial solution was injected into the cotyledons of pepper S8 seedlings at the cotyledon unfolding stage (14 days after sowing) using a syringe. The inoculated plants were then cultured at 22℃ under 16-hour light conditions for 3-4 weeks, and phenotypic changes were observed.

[0054] (6) Phenotypic observation and molecular verification: Observe and record the phenomenon of axillary bud shortening or elongation, as well as the plant albinism caused by PDS gene silencing, such as... Figure 3 As shown in Figure A. After stable and observable phenotypic changes were observed, the expression of the pTRV2e-CMV2b vector in pepper PDS plants and CaHAM-silenced plants was detected by agarose gel electrophoresis migration assay, as shown in Figure A. Figure 3 As shown in B, the pTRV2e-CMV2b vector-specific primers were expressed in TRV2:00, TRV2:PDS, and TRV2:CaHAM plants, but not in the negative control CK. This indicates that the viral vector was successfully loaded into the plant. The entire experiment required three biological replicates to ensure the reliability of the results.

[0055] Compared with the TRV2:00 control plants, the axillary buds of the 1st, 2nd, and 3rd internodes of CaHAM-silenced plants were significantly shortened by approximately 67.4%, 91.5%, and 74%, respectively (2-way ANOVA, p<0.05). Figure 3 As shown in D, RNA was extracted from the lateral buds of positive plants, reverse transcribed into cDNA, and then the expression level of CaHAM in the silenced plants was detected by qRT-PCR. Compared with the control plants, the expression level of CaHAM was significantly reduced, decreasing by approximately 86.6% (t-test, p<0.05). Figure 3 As shown in Figure C, CaHAM positively regulates lateral bud elongation.

[0056] The above embodiments demonstrate that the present invention successfully identified the CaHAM gene in chili peppers, which encodes a protein located in the cell nucleus and is highly expressed in axillary buds and growing points. Specific silencing of this gene using the VIGS technique significantly inhibits the elongation of lateral branches in chili peppers. Therefore, the CaHAM gene positively regulates lateral branch elongation in chili peppers, providing a key gene target and effective technical means for breeding new short-branch chili pepper varieties suitable for mechanized harvesting.

Claims

1. The application of the CaHAM gene or CaHAM protein in the regulation of lateral branches in pepper, characterized in that, The nucleotide sequence of the CaHAM gene is shown in SEQ ID NO: 1, and the amino acid sequence of the CaHAM protein is shown in SEQ ID NO:

2.

2. The application as described in claim 1, characterized in that, Pepper plants with shortened lateral branches are obtained by reducing or inhibiting the expression of the CaHAM gene, or by reducing or inhibiting the activity of the CaHAM protein.

3. The application of a recombinant vector in cultivating short-lateral-branch pepper plants, characterized in that, The recombinant vector contains a nucleotide fragment capable of reducing or inhibiting the expression of the endogenous CaHAM gene in pepper plants. The nucleotide sequence of the CaHAM gene is shown in SEQ ID NO: 1, and the amino acid sequence of the protein it encodes is shown in SEQ ID NO:

2.

4. The application as described in claim 3, characterized in that, The recombinant vector is a virus-induced gene silencing vector.

5. The application as described in claim 3, characterized in that, The nucleotide fragment expressed by the endogenous CaHAM gene in the chili plant is a specific fragment of the CaHAM gene, and its nucleotide sequence is shown in SEQ ID NO:

3.

6. A method for cultivating chili pepper plants with shortened lateral branches, characterized in that, The expression of the CaHAM gene is reduced or inhibited in pepper plants, or the activity of the CaHAM protein is reduced or inhibited to obtain pepper plants with shortened lateral branches; wherein the nucleotide sequence of the CaHAM gene is shown in SEQ ID NO: 1, and the amino acid sequence of the CaHAM protein is shown in SEQ ID NO:

2.

7. The method as described in claim 6, characterized in that, The reduction or inhibition is achieved by introducing the recombinant vector as described in any one of claims 3-5 into the pepper plant.

8. The method as described in claim 6, characterized in that, The reduction or suppression is achieved by knocking out or silencing the CaHAM gene using gene editing technology.

9. A recombinant vector, characterized in that, The recombinant vector comprises a VIGS vector backbone for inducing gene silencing and an insert fragment, the nucleotide sequence of which is shown in SEQ ID NO:

3.

10. The recombinant vector as described in claim 9, characterized in that, The VIGS vector backbone is the pTRV2e-CMV2b vector; the insert fragment is cloned into the SamI restriction site of the pTRV2e-CMV2b vector.

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