Application of Rice OsLBD Gene in Improving Rice Resistance to Bacterial Blight

Abstract

The present invention belongs to the field of genetic engineering technology and specifically relates to the use of a rice OsLBD gene for improving rice resistance to bacterial blight. The nucleotide sequence of the OsLBD gene is shown in SEQ ID No. 1. The present invention reveals the regulatory mechanism of rice disease resistance at the molecular level, identifies a new gene associated with disease resistance, and applies it to inhibit rice bacterial blight, laying the foundation for breeding rice varieties resistant to bacterial blight.

Description

Technical Field

[0001] The invention belongs to the technical field of genetic engineering, and particularly relates to an application of a rice OsLBD gene in improving the resistance of rice to bacterial blight. Background Art

[0002] Rice, an annual herbaceous plant of the genus Oryza in the grass family, is a major food crop and is closely related to people's lives. In recent years, rice diseases have seriously threatened rice production, mainly rice blast, rice false smut, and rice bacterial blight.

[0003] Rice bacterial blight is the world's leading bacterial disease of rice. Primarily caused by infection with Xanthomonas oryzae (Xoo), it is a major disease in rice production. Its prevalence leads to reduced seed set and 1000-grain weight. With changing climate conditions and planting practices, the frequency and severity of rice bacterial blight have increased annually, posing a significant challenge to rice yield and quality.

[0004] These diseases have the most severe impact on rice yield and quality. While the use of pesticides can mitigate the impact of the diseases, they can also leave pesticide residues and negatively impact the natural environment. Therefore, there is an urgent need for new strategies to combat rice bacterial blight. Summary of the Invention

[0005] In order to reduce the damage caused by rice bacterial blight, the present invention provides an application of a rice OsLBD gene in improving the resistance of rice to rice bacterial blight.

[0006] The technical solution adopted in the present invention is:

[0007] A first aspect of the present invention provides a use of a rice OsLBD gene in improving resistance of rice to bacterial blight. The nucleotide sequence of the OsLBD gene is shown in SEQ ID No. 1.

[0008] The second aspect of the present invention provides an overexpression vector comprising the nucleotide sequence.

[0009] The third aspect of the present invention provides a method for preparing the overexpression vector, comprising the following steps:

[0010] A pair of primers were synthesized, wherein the sequences of the primers are shown in SEQ ID No. 3 and SEQ ID No. 4;

[0011] Extracting rice RNA, reverse transcribing it into cDNA, and using the cDNA as a template to amplify by PCR using the primers to obtain the OsLBD gene;

[0012] The OsLBD gene was connected to the expression vector after enzyme digestion, and transformed to obtain an overexpression vector.

[0013] Preferably, the expression vector includes any one of the pCAMBIA series vectors and the pBI series vectors.

[0014] Preferably, the pCAMBIA series vectors include any one of pCAMBIA3301, pCAMBIA1300 and pCAMBIA1305;

[0015] The pBI series vectors include any one of pBI121 and pBI101;

[0016] A fourth aspect of the present invention provides a use of the overexpression vector, wherein the overexpression vector is used to prepare rice plants overexpressing the OsLBD gene, and the preparation process comprises the following steps:

[0017] preparing an Agrobacterium bacterial solution containing the overexpression vector, and using the Agrobacterium bacterial solution to infect rice;

[0018] The infected rice was cultured to obtain rice plants overexpressing the OsLBD gene.

[0019] Preferably, when infecting rice, the rice variety used for infection is Nipponbare.

[0020] Preferably, the Agrobacterium bacterial solution is used to infect rice callus tissue.

[0021] A fifth aspect of the present invention provides an application of the overexpression vector, wherein the overexpression vector is used to improve the resistance of rice to bacterial blight.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention provides a use of a rice OsLBD gene for improving rice resistance to bacterial blight. The nucleotide sequence of the OsLBD gene is shown in SEQ ID No. 1. The present invention reveals the regulatory mechanism of rice disease resistance at the molecular level, identifies a new gene associated with disease resistance, and applies it to inhibiting rice bacterial blight, laying the foundation for breeding rice varieties resistant to bacterial blight.

[0024] Researchers have discovered that the rice genes OsLBD11 / OsLBD12 play a crucial role in rice resistance to bacterial blight. Deletion of the OsLBD11 / OsLBD12 genes reduces rice's basal defense against the pathogen, while overexpression of the OsLBD11 / OsLBD12 genes significantly enhances their basal defense against the pathogen. Therefore, the OsLBD11 / OsLBD12 genes can be used to regulate rice resistance to bacterial blight.

[0025] Disease-resistant breeding is currently the most cost-effective method for combating pathogens. Discovering new bacterial blight-resistance genes and resources, and cultivating broad-spectrum disease-resistant varieties, is a green and efficient strategy for ensuring crop yield and quality, and is of great significance to agricultural production. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Figure 2 shows the results of identifying the resistance of rice overexpression lines to bacterial blight. A is a greenhouse pot inoculation diagram, which shows, from left to right, three parallel samples of NIP, three parallel samples of OsLBD11 / 12-OE1, and three parallel samples of OsLBD11 / 12-OE2. B is a statistical diagram of the lesion length on diseased leaves, where *** indicates a significant difference at P < 0.001.

[0027] Figure 2 Figure 3 is the expression result of rice defense-related genes in rice overexpression lines. A is the relative expression level detection result of OsPR1b gene after flg22 treatment; B is the relative expression level detection result of OsPR10 gene after flg22 treatment; C is the relative expression level detection result of OsPR1b gene after chitin treatment; D is the relative expression level detection result of OsPR10 gene after chitin treatment, where a and b represent significant differences at P < 0.05.

[0028] Figure 3 Figure 2 shows the results of the resistance identification of rice knockout lines to bacterial blight. A is a greenhouse pot inoculation diagram, which includes three parallel samples of ZH11, three parallel samples of oslbd11 / 12-22, and three parallel samples of oslbd11 / 12-24 from left to right. B is a statistical diagram of the lesion length on diseased leaves, where *** indicates a significant difference at P < 0.001.

[0029] Figure 4These are the expression results of rice defense-related genes in rice knockout lines. A is the relative expression level detection result of OsPR1b gene after flg22 treatment; B is the relative expression level detection result of OsPR10 gene after flg22 treatment; C is the relative expression level detection result of OsPR1b gene after chitin treatment; D is the relative expression level detection result of OsPR10 gene after chitin treatment, where a and b represent significant differences at P < 0.05. DETAILED DESCRIPTION

[0030] The present invention will be further described below by way of specific examples, but the scope of the present invention is not limited thereto. The details and forms of the technical solution of the present invention may be modified or replaced without departing from the spirit and scope of the present invention, but such modifications or replacements fall within the scope of protection of the present invention.

[0031] The inventive concept of the present invention is as follows:

[0032] Rice bacterial blight is the world's leading bacterial disease of rice. Primarily caused by infection with Xanthomonas oryzae (Xoo), it is a major disease in rice production. Its prevalence leads to reduced seed set and 1000-grain weight. With changing climate conditions and planting practices, the frequency and severity of rice bacterial blight have increased annually, posing a significant challenge to rice yield and quality.

[0033] These diseases have the most serious impact on rice yield and quality. While the use of pesticides can mitigate the impact of the diseases, pesticide use can leave residues and negatively impact the natural environment. Therefore, there is an urgent need for a new strategy to combat rice bacterial blight.

[0034] Based on this, the present invention provides an application of the rice OsLBD gene in improving rice resistance to bacterial blight. The present invention reveals the regulatory mechanism of rice disease resistance at the molecular level, finds a new gene related to disease resistance regulation, and applies it to inhibit rice bacterial blight, laying the foundation for breeding rice varieties resistant to bacterial blight. The present invention has found through research that the rice genes OsLBD11 / OsLBD12 play an important role in the process of rice resistance to bacterial blight. Rice that overexpresses the OsLBD11 / OsLBD12 genes can significantly improve the basic defense ability of rice against bacterial blight pathogens, so the rice OsLBD11 / OsLBD12 genes can be used to regulate rice resistance to bacterial blight.

[0035] In order to make those skilled in the art better understand the technical solution of the present invention and be able to implement it, the present invention is further described below in conjunction with specific examples. In the description of the present invention, if not otherwise specified, the reagents used are all commercially available and the methods used are all conventional techniques in the art.

[0036] Example 1

[0037] The application of rice OsLBD gene in improving rice resistance to bacterial blight is as follows:

[0038] 1. Obtaining rice OsLBD gene overexpression mutants.

[0039] The CDS sequence of the rice OsLBD gene is shown in SEQ ID No. 1, and the amino acid sequence is shown in SEQ ID No. 2.

[0040] The OsLBD genes described in the present invention include OsLBD11 and OsLBD12. The gene number of OsLBD11 is LOC_Os11g01550; the gene number of OsLBD12 is LOC_Os12g01550. OsLBD11 and OsLBD12 are located on different chromosomes, but their CDS sequences are exactly the same. Therefore, the present invention constructs plants overexpressing OsLBD11 or OsLBD12 based on the sequence shown in SEQ ID No. 1.

[0041] The present invention utilizes the pCAMBIAI1305 vector to overexpress the sequence shown in SEQ ID No. 1 to obtain an overexpression vector, and further utilizes the overexpression vector to obtain an overexpression plant.

[0042] The steps for constructing the overexpression vector are as follows:

[0043] (1) Based on the sequence shown in SEQ ID No. 1, primers OEOsLBD11 / OsLBD12-F and OEOsLBD11 / OsLBD12-R were synthesized. The primer sequences are shown in SEQ ID No. 3 and SEQ ID No. 4:

[0044] SEQ ID No.3, OEOsLBD11 / OsLBD12-F:

[0045] TGTACAGAGCTCGGTACCATGCGAGTCTTAGGATTAAC.

[0046] SEQ ID No.4, OEOsLBD11 / OsLBD12-R:

[0047] GTCTTTGTAGTCAAGCTTGTTTGAGCTCATTACCCCTG.

[0048] (2) Amplification of target fragment: RNA was extracted from Nipponbare and reverse transcribed into cDNA. Using cDNA as a template, the reaction system was mixed in a 50 μL centrifuge tube and PCR amplified to obtain the target fragment. The reaction system is described in Table 1.

[0049] Table 1 PCR reaction system

[0050] Reagents 50 μL reaction system 2×PhantaMaxBuffer 25 μL dNTPMix, 10 mM each 1 μL Template DNA 400ng 10 μM Forward Primer 2μL 10 μM Verified Primer 2μL PhantaMax Super-FidelityDNA Polymerase, 1U / μL 1 μL <![CDATA[ddH2O]]> Add to 50 μL

[0051] The mixed reaction system was used for gene amplification in a PCR instrument, wherein the PCR reaction conditions were set as shown in Table 2.

[0052] Table 2 PCR reaction conditions

[0053]

[0054] (3) Enzyme digestion of the expression vector.

[0055] Double-digest the desired expression vector pCAMBIAI1305 with Kpn I and Hind III. Mix the reaction mixture in a 200 μL centrifuge tube and incubate at 37°C in a water bath for 3 h. See Table 3 for the enzyme digestion system.

[0056] Table 3 Enzyme digestion system

[0057] Reagents 50 μL reaction system Plasmid vector pCAMBIAI1305 3000ng KpN 3μL HindⅢ 3μL 10×rCutSmartbuffer 5μL <![CDATA[ddH2O]]> Add to 50 μL

[0058] (4) Obtaining glue recovery products.

[0059] After the reaction of (2) and (3) above was completed, 10× Loading Buffer was added to each tube, and the fragment size was verified by electrophoresis using 1% agarose gel at 150 V. The target fragment band in the gel was recovered and purified using a gel recovery kit, and the recovered product was stored in a -20°C refrigerator.

[0060] The experimental method refers to the agarose gel DNA recovery kit, which was purchased from Kangwei Century Biological Reagent Co., Ltd. The method of using the agarose gel DNA recovery kit is as follows:

[0061] ①Put the cut target gel into a 2mL centrifuge tube and weigh it. Add 1 volume of PG Buffer and place it in a 65℃ dry bath to dissolve the gel. Invert and mix until completely dissolved. Then take it out and cool it to room temperature.

[0062] ② Equilibration of adsorption column: Add 200 μL of LPS Buffer to the adsorption column and centrifuge at 12,000 rpm for 1 minute.

[0063] ③ Remove the waste liquid, add the gel solution to the adsorption column, place it at room temperature for 2 minutes, and centrifuge it at 12000 rpm for 1 minute.

[0064] ④ Remove the waste liquid and add 500 μL PW Buffer to the adsorption column for rinsing. Centrifuge at 12000 rpm for 1 min and rinse again.

[0065] ⑤ Remove the waste liquid and centrifuge the empty column at 12000rpm for 3min to remove the residual ethanol.

[0066] ⑥ Place the adsorption column in a new 1.5 mL centrifuge tube and open the lid. Leave it at room temperature for 5 minutes to evaporate the ethanol.

[0067] ⑦ Add 50 μL of 65 μL preheated EB Buffer to the adsorption column, let it stand for 1 minute, centrifuge at 12000 rpm for 1 minute to obtain the DNA solution, and store it at -20 ℃ for later use.

[0068] (5) Obtain overexpression vector using homologous recombination.

[0069] The experimental method refers to the cloning kit of Nanjing Novozyme Biotechnology Co., Ltd., and the steps are as follows:

[0070] ① Use DNA ligase to ligate the digested expression vector pCAMBIAI1305 and the target fragment. Mix the reaction system in a 200 μL centrifuge tube and incubate in a 37° water bath for 30 minutes to obtain the recombinant product. The ligation system is shown in Table 4.

[0071] Table 4 Connection system

[0072] Reagents 20 μL reaction system Expression vector after enzyme digestion 10 μL target gene 2μL ExnaseⅡ 2μL 5×Cell buffer 4 μL <![CDATA[ddH2O]]> Add to 20 μL

[0073] ② Thaw the cloning competent cells DH5α Competent cells on ice. DH5α Competent cells were purchased from Vazyme with the product number #C502.

[0074] ③ Add 10 μL of recombinant product to 100 μL of competent cells, gently tap the tube wall to mix, do not shake to mix, and let it stand on ice for 30 minutes.

[0075] ④After heat shock in a 42℃ water bath for 45s, immediately cool on ice for 3min.

[0076] ⑤ Add 900 μL of LB without antibiotics and shake at 37°C for 1 h at 250 rpm.

[0077] ⑥ Preheat the LB solid culture medium plate containing the corresponding antibody in a 37°C incubator.

[0078] ⑦ Centrifuge at 5000 rpm, 2400 g for 5 minutes. Remove 900 μL of supernatant in a clean bench. Resuspend the cells in the remaining culture medium and spread them evenly on a plate containing antibiotics using a sterile spreader.

[0079] ⑧Incubate inverted in a 37℃ constant temperature incubator for 16 hours.

[0080] ⑨ Pick a single clone of transformant colonies from the plate and place them in a test tube containing 5 mL of LB liquid medium supplemented with antibiotics. Place the tube at an angle in a constant temperature shaker at 37°C and 180 rpm for 12 hours.

[0081] ⑩ Take part of the bacterial liquid and use a plasmid mini-extraction kit to purify the plasmid. The plasmid purified by the plasmid mini-extraction kit was purchased from Tiangen Biochemical Technology (Beijing) Co., Ltd., product number DP103. Use PCR technology and first-generation sequencing technology to verify whether the target gene is successfully and correctly connected to the plasmid vector. If the construction is successful, mix the remaining bacterial liquid with 40% glycerol in a 1:1 ratio and place it in a -80℃ refrigerator for long-term storage.

[0082] The above process is as follows: Using the NIP genome as a template, the gene sequence was amplified using primers SEQ ID No. 3 and SEQ ID No. 4. After purification, the amplified product was ligated into the pCAMBIAI1305 vector via homologous recombination. The ligated plasmid was transformed into Escherichia coli using the heat shock method, and positive clones were selected for testing. After correct sequencing, the plasmid was sent to Wuhan Boyuan Biotechnology Co., Ltd.

[0083] The method for preparing an overexpression plant using the overexpression vector is as follows:

[0084] Agrobacterium EHA105 was used to prepare an Agrobacterium culture containing the above-mentioned overexpression vector, and rice callus tissue was infected through the Agrobacterium-mediated method using the Nipponbare NIP line as the background. The infected rice was cultured to obtain two rice plants overexpressing OsLBD11 / OsLBD12, namely OsLBD11 / 12-OE1 and OsLBD11 / 12-OE2.

[0085] 2. Obtaining rice OsLBD gene knockout mutants.

[0086] The present invention uses Crispr / Cas9 technology to perform targeted knockout of the target gene OsLBD, thereby obtaining a knockout mutant of the OsLBD11 / OsLBD12 gene.

[0087] The steps for constructing the knockout vector are as follows:

[0088] First, the reference sequence of OsLBD11 from Nipponbare was downloaded based on its gene ID LOC_Os11g01550.1. The gene ID of OsLBD12 is LOC_Os12g01550.1. Since the CDS sequence of OsLBD12 is exactly the same as that of OsLBD11, materials with mutations in both genes were constructed.

[0089] The position of target site 1 was determined to be CGTCAGCAGCCTCGTCTACGAGG, and the position of target site 2 was determined to be CTGCAGCTGGAGTTGCAGGGCGG, and linker primer F and linker primer R were designed. The primer sequences of linker primer F and linker primer R are shown in SEQ ID No. 5 and SEQ ID No. 6.

[0090] SEQ ID No.5:

[0091] cgcgctgtcgcttgtgtgGTCAGCAGCCTCGTCTACGGTTTTagagctagaaa.

[0092] SEQ ID No.6:

[0093] CTATTTCTAGCTCTAAAACCCCTGCAACTCCAGCTGCACGCCACGGAT CATCTGCA.

[0094] The construction of rice OsLBD gene knockout strains was completed by Weimi Biotechnology Co., Ltd., and two knockout strains, oslbd11 / 12-22 and oslbd11 / 12-24, were successfully obtained.

[0095] 3. Effects of rice OsLBD knockout and overexpression lines on resistance to bacterial blight.

[0096] To verify that the genes OsLBD11 / OsLBD12 are involved in rice's defense response to bacterial blight, we tested the resistance of OsLBD11 / OsLBD12 knockout and overexpression lines to bacterial blight. The specific procedures are as follows:

[0097] Reactivate the laboratory-maintained bacterial blight strain PXO99A. Incubate in NA liquid medium at 28°C with shaking at 200 rpm for 12 hours. Resuspend the collected PXO99A cells in 10 mM MgCl₂ solution and adjust the OD₀₀ to 0.8. Use sterilized scissors to inoculate the PXO99A bacterial suspension along the distal cuts of rice leaves from OsLBD11 / OsLBD12 knockout and overexpression lines. Measure and count the lesion lengths 14 days after inoculation.

[0098] The rice bacterial blight strain PXO99A is disclosed in the reference: Zeng Chen. Rice bacterial blight pathogen PXO99 A Construction of strain MCP-free mutant and study of chemotactic receptor genes[D]. Guangxi University, 2019.

[0099] Compared with the wild-type ZH11, the lesion lengths of the knockout lines oslbd11 / 12-22 and oslbd11 / 12-24 were significantly longer than those of the wild-type ZH11, indicating that the resistance to bacterial blight was significantly weakened. Figure 3 The lesion lengths of the overexpression lines OsLBD11 / 12-OE1 and OsLBD11 / 12-OE2 were significantly shorter than those of the wild-type NIP, indicating that OsLBD11 / OsLBD12 are positive regulators of rice resistance to bacterial blight. Figure 1 . Figure 1 A and Figure 3 In A, the upward red horizontal line indicates the location where the lesion appears.

[0100] 4. Detection of PR gene expression in rice OsLBD11 / OsLBD12 knockout and overexpression lines after inoculation with bacterial blight pathogen.

[0101] After sterilizing the rice seeds of wild type, knockout strain and overexpression strain, they were cultured on 1 / 2MS solid for 7 days, and then rice seedlings of uniform size were selected and transferred to 1 / 2MS liquid culture medium for 3 days. The liquid culture medium was quickly removed, and 1μM Flg22+0.01% surfactant by volume and 100μg / mL chitin+0.01% surfactant by volume were added to the new liquid culture medium. At the same time, an equal volume of sterile water was set as the MOCK group. After treating for 6 hours, the samples were immediately taken and stored at -80°C. The total RNA of the sample was extracted using Trizol reagent, and then 1μg was reverse transcribed and synthesized into cDNA using M-MLV reverse transcriptase and Olig (dT). The rice gene OsActin was used as an internal reference. Real-time fluorescence quantitative PCR was performed on rice defense-related genes, and 2- ΔΔCT The relative expression of genes was calculated by Figure 2 and Figure 4 As shown in the results, after treatment with 1 μM Flg22 or 100 μg / mL Chitin, the expression levels of OsPR1b and OsPR10 genes in the rice overexpression lines were significantly upregulated, while the expression levels of OsPR1b and OsPR10 genes in the rice knockout lines were significantly downregulated, indicating that OsLBD11 / OsLBD12 can positively regulate the innate basal immune response of rice.

[0102] The real-time fluorescence quantitative PCR reaction system is shown in Table 5, the reaction conditions of the real-time fluorescence quantitative PCR reaction system are shown in Table 6, and the real-time fluorescence quantitative PCR reaction primer sequences are shown in Table 7.

[0103] Table 5 Real-time fluorescence quantitative PCR reaction system

[0104] Reagents 20 μL reaction system 2×FastSYBR Mixture 10 μL 10 μM Forward Primer 0.4μL 10 μM Verified Primer 0.4μL Template DNA 2μL <![CDATA[ddH2O]]> 7.2μL

[0105] Table 6 Reaction conditions of real-time fluorescence quantitative PCR reaction system

[0106]

[0107] Table 7 Primer sequences

[0108]

[0109]

[0110] Figure 1 and Figure 3 *** represents P < 0.001.

[0111] Figure 2 and Figure 4 Different lowercase letters above the bars indicate significant differences in gene expression levels, P < 0.05.

[0112] SEQ ID No. 1:

[0113] ATGGCGGGAAGCGGGAGCGGGACACCGTGCGCGTCGTGCAAGCTGCTGCGGCGGCGGTGCACGTCGGAGTGCGTGTTCGCGCCCTACTTCCCGGCGGAGGAGGCGCAGCGGTTCGCCATGGTGCACCGGGTGTTCGGCGCCAGCAACGTCAGCAAGATGCTGCTCGATGTGCCGCCGCCGCAGAGGCCCGACGCCGTCAGCAGCCTCGTCTACGAGGCCAACGCCCGTATGAGGGA CCCCGTCTACGGCTGCGTCGCCGCCATCTCCTTCCTCCAGAACCAAGTCTCCCAGCTCCAGATGCAGCTCGCCCTCGCCCACGCCGAGACCGCCGCCCTGCAACTCCAGCTGCAGCAGCAGCACCAAGATCAAGATGACCACCACCAGCAGTGCATCCTGGAGAATGCTGCTGCTCATCACCAGCTGATGCTGCAGGAGGCATTCCTCAAGAAAGAGTCCATGTGGACATAA.

[0114] SEQ ID No. 2:

[0115] MAGSGSGTPCASCKLLRRRCTSECVFAPYFPAEEAQRFAMVHRVFGASNVSKMLLDVPPPQRPDAVSSLVYEANARMRDPVYGCVAAISFLQNQVSQLQMQLALAHAETAALQLQLQQQHQDQDDHHHQQCILENAAAHHQLMLQEAFLKKESMWT.

[0116] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0117] The above-described embodiments merely illustrate several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, and all such variations and improvements fall within the scope of protection of the present invention.

Claims

1. Application of rice OsLBD gene in improving rice resistance to bacterial blight, characterized in that: The nucleotide sequence of the OsLBD gene is shown in SEQ ID No.

1.

2. An application of an overexpression vector, characterized in that: The overexpression vector is used to improve the resistance of rice to bacterial blight; The overexpression vector comprises the nucleotide sequence of claim 1.

3. The use according to claim 2, characterized in that The preparation method of the overexpression vector comprises the following steps: A pair of primers were synthesized, wherein the sequences of the primers are shown in SEQ ID No. 3 and SEQ ID No. 4; Extracting rice RNA, reverse transcribing it into cDNA, and using the cDNA as a template to amplify by PCR using the primers to obtain the OsLBD gene; The OsLBD gene was connected to the expression vector after enzyme digestion, and transformed to obtain an overexpression vector.

4. The use according to claim 3, characterized in that The expression vector includes any one of the pCAMBIA series vectors and the pBI series vectors.

5. The use according to claim 4, characterized in that The pCAMBIA series vectors include any one of pCAMBIA3301, pCAMBIA1300 and pCAMBIA1305; The pBI series vectors include any one of pBI121 and pBI101.

6. The use according to claim 2, characterized in that The overexpression vector is used to prepare rice plants that overexpress the OsLBD gene, thereby improving the resistance of rice to bacterial blight. The process of preparing rice plants that overexpress the OsLBD gene includes the following steps: preparing an Agrobacterium bacterial solution containing the overexpression vector, and using the Agrobacterium bacterial solution to infect rice; The infected rice was cultured to obtain rice plants overexpressing the OsLBD gene.

7. The use according to claim 6, characterized in that When infecting rice, the rice variety used for infection is Nipponbare.

8. The use according to claim 6, characterized in that When infecting rice, the Agrobacterium bacterial solution is used to infect rice callus tissue.

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