Application of ospp2act gene and its encoded protein in improving rice sheath blight resistance

Abstract

The application discloses an OsPP2Act gene and application of a coded protein thereof in improving sheath blight resistance of rice, identifies a new sheath blight resistance regulating gene of rice, and finds that overexpression of one gene OsPP2Act in an OsPP2A family can reduce the sheath blight resistance of rice through sheath blight resistance identification and expression mode analysis of the OsPP2A family, and the sheath blight resistance of rice is enhanced by knocking out the gene by using a CRISPR / Cas9 gene editing technology. It is shown that the OsPP2Act gene negatively regulates the sheath blight resistance level of rice, and has a good application prospect in cultivating sheath blight resistant rice varieties, and lays an important foundation for sheath blight resistant rice breeding.

Description

Technical Field

[0001] This invention belongs to the field of plant genetic engineering technology, specifically relating to the improvement and application of a gene OsPP2Act and its encoded protein in rice sheath blight resistance. Background Technology

[0002] Rice sheath blight is one of the three major diseases affecting rice, primarily damaging the leaf sheath and leaves. It is characterized by its high susceptibility, widespread prevalence, and broad host range, severely impacting high and stable rice yields. Transgenic rice breeding technology has been widely applied, offering advantages such as short cycles and high efficiency. Manipulation of rice genes through transgenic technology has led to the development of numerous disease-resistant and high-yielding new rice varieties. However, due to the scarcity of sheath blight resistance genes and lagging research into the resistance mechanisms, progress in sheath blight resistance breeding has been slow. Discovering sheath blight resistance genes can provide genetic resources and a theoretical basis for molecular breeding for sheath blight resistance.

[0003] Protein phosphatase 2A (PP2A) is an important class of serine / threonine phosphatases that participate in protein dephosphorylation, helping to regulate various plant signal transduction, gene expression, metabolic pathways, and cell death, and playing a significant role in improving crop stress resistance. The PP2A holoenzyme is a heterotrimer composed of a structural subunit A, a regulatory subunit B, and a conserved catalytic subunit C. Each subunit exists either as a monomer or as a core enzyme composed of the catalytic and structural subunits. The diversity of the B subunit determines the wide variability in substrate recognition and subcellular localization of the holoenzyme. However, the relationship between rice protein phosphatase PP2A and rice sheath blight resistance has not yet been reported. Summary of the Invention

[0004] Objective: To address the shortcomings of existing technologies, this invention provides the application of the OsPP2Act gene in improving rice sheath blight resistance. This invention identifies a novel rice sheath blight resistance regulatory gene, OsPP2Act. Through sheath blight resistance identification and expression pattern analysis of the OsPP2A family, it was found that overexpression of the OsPP2Act gene reduces rice resistance to sheath blight, while knocking out this gene using CRISPR / Cas9 gene editing technology enhances rice resistance to sheath blight. This indicates that OsPP2Act negatively regulates rice resistance to sheath blight and has good application prospects in breeding sheath blight-resistant rice varieties, effectively improving rice resistance to sheath blight.

[0005] The present invention also provides the protein encoded by the gene and its applications.

[0006] Technical solution: In order to achieve the above objectives, the present invention relates to the application of the OsPP2Act gene in regulating the resistance of rice to sheath blight, wherein the sequence of the OsPP2Act gene is as shown in SEQ ID NO.1.

[0007] The overexpression of the gene OsPP2Act reduces rice's resistance to sheath blight, while knocking out the gene enhances rice's resistance to sheath blight.

[0008] The present invention relates to the application of the OsPP2Act protein encoded by the OsPP2Act gene in regulating the resistance of rice to sheath blight. The OsPP2Act protein is encoded by SEQ ID NO.1, and its amino acid sequence is shown in SEQ ID NO.2.

[0009] The present invention relates to the application of cDNA or genomic DNA molecules that have 75% or more identity with the OsPP2Act gene, or that hybridize with the OsPP2Act gene and encode the OsPP2Act protein, in regulating the resistance of rice to sheath blight.

[0010] The present invention relates to the application of recombinant vectors, recombinant microorganisms, or transgenic plant cell lines containing the OsPP2Act gene in regulating the resistance of rice to sheath blight.

[0011] The vector may be a plasmid, granule, bacteriophage, or viral vector; the microorganism may be yeast, bacteria, algae, or fungi, such as Agrobacterium; the transgenic plant cell line does not include propagation material.

[0012] The application of the OsPP2Act gene or OsPP2Act protein, or the recombinant vector, recombinant microorganism, or transgenic plant cell line described in this invention in the cultivation of transgenic rice with enhanced resistance to sheath blight.

[0013] The present invention discloses a method for cultivating transgenic rice with reduced or increased resistance to sheath blight, comprising enhancing or reducing the expression level and / or activity of OsPP2Act protein in recipient rice to obtain transgenic rice; the transgenic rice has lower or higher disease resistance than the recipient rice.

[0014] The disease resistance of the transgenic rice is higher / lower than that of the recipient rice, which is reflected in the fact that the length of the sheath blight lesions of the transgenic rice is smaller / higher than that of the recipient rice.

[0015] The method for enhancing or reducing the expression level and / or activity of OsPP2Act protein in recipient rice is achieved by overexpressing or knocking out the gene encoding OsPP2Act protein in the recipient rice.

[0016] The method for cultivating transgenic rice with reduced or increased resistance to rice sheath blight, as described in this invention, is applied in the creation of new rice germplasm resistant to rice sheath blight.

[0017] In this invention, the rice variety described above can specifically be Dongjin.

[0018] This invention identified a gene, OsPP2Act, through reverse genetics. OsPP2Act encodes a catalytic subunit of the PP2A family of rice type 2A protein phosphatases. Results of rice sheath blight resistance identification showed that OsPP2Act negatively regulates rice resistance to sheath blight; that is, knocking out the OsPP2Act gene increases rice resistance to sheath blight, while overexpression of OsPP2Act significantly weakens rice resistance to sheath blight. These results indicate that OsPP2Act, as a negative regulator of sheath blight, has significant potential applications in molecular breeding for resistance to sheath blight.

[0019] In the application described in this invention, the disease resistance can be sheath blight resistance; the regulation is specifically manifested in that: when the activity and / or content of OsPP2Act protein in the plant decreases, the plant's resistance to sheath blight increases; when the activity and / or content of OsPP2Act protein in the plant increases, the plant's resistance to sheath blight decreases.

[0020] Specifically, the plant breeding mentioned above may involve creating new germplasm resistant to rice sheath blight.

[0021] The main steps in the above method for reducing the expression level and / or activity of the OsPP2Act gene in recipient rice are as follows: (1) Obtaining the target gene fragment. In this invention, the target fragments of all candidate genes are amplified from the gene corresponding to Nipponbare cDNA by PCR technology. (2) Ligating the target gene fragment to an intermediate (cloning) vector. 8 / GW / TA Kit; (3) Select positive clones and confirm them by sequencing; mix positive clone plasmids and final vector plasmids for recombination reaction; (4) PCR and plasmid enzyme digestion to verify positive clones; (5) Transform recombinant positive plasmids into Agrobacterium; (6) Verification and preservation of positive Agrobacterium single clones. In the experimental operation, total RNA was extracted from whole tissues of Nipponbare seedlings at the 4-5 leaf stage (leaf as plant), and was performed according to the Trizol method (Invitrogen); total cDNA synthesis was performed using the PrimeScript RTreagent Kit With gDNA Eraser kit (TaKaRa); recombinant plasmid extraction was performed using the EZNATM Plasmid Midi Kit kit (OMEGA). To enhance the expression level and / or activity of the OsPP2Act gene in recipient rice, the full-length coding sequence of the rice protein phosphatase catalytic subunit (ser / thr-PP2A catalytic subunit, PP2Ac) gene (named OsPP2Act) was amplified using high-fidelity DNA polymerase. The target gene was then introduced into the overexpression vector pCAMBIA1390, which was started by the strong promoter Ubi, via PstI.

[0022] Real-time quantitative PCR results showed that OsPP2Act was highly expressed mainly in leaves and leaf sheaths, which is consistent with the characteristic that rice sheath blight mainly damages leaf sheaths (e.g., Figure 1 A), and the expression of the OsPP2Act gene can be induced to be upregulated after infection with *Rhizoctonia solani* (e.g., ...). Figure 1 (B) This suggests that the OsPP2Act gene is closely related to rice sheath blight resistance. Sheath blight resistance identification showed that the transgenic overexpression lines had significantly longer sheath blight lesions than the wild type, while the gene-edited lines had significantly shorter sheath blight lesion lengths than the wild type. These results indicate that the OsPP2Act gene can regulate rice sheath blight resistance.

[0023] This invention identified the rice leaf sheath-specific OsPP2A gene—OsPP2Act (LOC_Os02g12580)—using qRT-PCR expression analysis. Located on chromosome 2, the gene is 4850 bp in length and contains 5 introns, with the coding sequence (CDS) encoding 308 amino acids. Significant induction of this gene was observed after infection with *Rhizoctonia solani*, suggesting a close relationship between the OsPP2Act gene and rice resistance to *Rhizoctonia solani*. Furthermore, overexpression technology was used to enhance the expression level of the OsPP2Act gene, and gene editing technology was used to knock out the OsPP2Act gene, confirming that this gene negatively regulates rice resistance to *Rhizoctonia solani*. The resistance trait of transgenic lines to *Rhizoctonia solani* was investigated, resulting in new rice materials with significantly enhanced resistance to *Rhizoctonia solani*.

[0024] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0025] This invention identifies a novel gene regulating resistance to rice sheath blight, providing a new gene resource for improving rice resistance to sheath blight and obtaining new rice germplasm with enhanced resistance to the disease. The invention identifies a gene, OsPP2Act, that regulates rice resistance to sheath blight. Silencing or knocking out this gene significantly enhances rice resistance to sheath blight, while overexpression weakens it, indicating that this gene has important application value in molecular breeding for resistance to sheath blight. Attached Figure Description

[0026] Figure 1 The expression patterns of the OsPP2Act gene in rice are shown. A shows the expression patterns of the OsPP2Act gene at different parts of the rice during the heading stage; B shows the expression patterns of the OsPP2Act gene in different varieties after inoculation with sheath blight pathogen.

[0027] Figure 2 The results are for 11 T0 plants overexpressing the OsPP2Act gene. A shows the RT-PCR results of the 11 T0 overexpressing plants; B shows the Western PCR results of the 11 T0 overexpressing plants.

[0028] Figure 3 The greenhouse sheath blight resistance phenotypes of OsPP2Act gene overexpressing lines and wild-type controls are shown. A shows the lesion length 7 days after greenhouse inoculation; B shows the greenhouse inoculation phenotype; C shows the Western spectral analysis results of OsPP2Act protein in the overexpressing lines before inoculation.

[0029] Figure 4 The greenhouse sheath blight resistance phenotypes are shown for gene-edited lines of the OsPP2Act gene and wild-type controls. A represents the genotype of the gene-edited line; B represents the lesion length 7 days after in vitro inoculation in the climate chamber; C represents the in vitro inoculation phenotype in the climate chamber.

[0030] Figure 5 The phenotypes of OsPP2Act gene overexpressing lines and wild-type controls in climatology chambers for resistance to and susceptibility to sheath blight are shown. A represents the lesion length 7 days after in vitro inoculation in the climatology chamber; B represents the phenotype after in vitro inoculation in the climatology chamber; C represents the Western spectral analysis results of OsPP2Act protein in overexpressing lines before inoculation.

[0031] Figure 6 The phenotypes of gene-edited strains of the OsPP2Act gene and wild-type controls in vitro in vitro sheath blight resistance in climate chambers are shown. A is the genotype of the gene-edited strain; B is the lesion length 7 days after in vitro inoculation in the climate chamber; C is the phenotype after in vitro inoculation in the climate chamber. Detailed Implementation

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0033] The conventional rice varieties Dongjin, NIP, Minghui 63, Chenghui 727, Yangdao 6, and Taijing 394, as well as the rice sheath blight resistant germplasm YSBR1 (Zuo Shimin et al., Evaluation of resistance to rice sheath blight improved new resistance source YSBR1 [J]. Acta Agronomica Sinica, 2009, 35(04):608-614.) were provided by Yangzhou University;

[0034] The moderately pathogenic Rhizoctonia solanii strain YN-7 (Lee DY et al., Comparative genome analyses of four rice-infecting Rhizoctonia solaniisolates reveal extensive enrichment of homogalacturonan modification genes. BMC Genomics. 2021 Apr 7;22(1):242.) was provided by the Department of Plant Protection, Yangzhou University.

[0035] Example 1

[0036] Cloning of the CDS region of the OsPP2Act gene

[0037] Nipponbare (NIP) seeds were cultured into seedlings. Total RNA was extracted from the leaves of NIP seedlings at the 4-5 leaf stage using the Trizol method (Invitrogen). Total cDNA was synthesized using the PrimeScript RT reagent Kit With gDNA Eraser (TaKaRa). Primers were designed based on sequence information: OsPP2Act-CDS-F: 5'-ATGCCGTCGTCGCACGGG-3' and OsPP2Act-CDS-R: 5'-CAAAAAGTAGTCGGGAGTCT-3'. The gene was cloned and amplified using NIP cDNA as a template. The nucleotide sequence of the CDS of the rice OsPP2Act gene of this invention is shown in SEQ ID NO.1, and the amino acid sequence is shown in SEQ ID NO.2.

[0038] Example 2

[0039] Expression characteristics analysis of OsPP2Act gene

[0040] Samples of different organs (roots, stems, leaves, leaf sheaths, and panicles) of the rice variety Dongjin during the booting stage were collected and preserved in liquid nitrogen. NIP, YSBR1, Minghui 63, Chenghui 727, Yangdao 6, and Taijing 394 were cultured under normal conditions to the booting stage. Using the embedding method (Zuo Shimin et al., Establishment and Improvement of Field Rice Sheath Blight Resistance Identification System [J]. Journal of Yangzhou University: Agriculture and Life Sciences Edition. 2007(27):57-61), a piece of wood bark (1 cm long and 2 mm wide, covered with herbicide of Sheath Blight) was carefully embedded into the leaf sheath 1-2 cm below the second leaf from the bottom of the rice. The six different rice varieties were inoculated with the herath blight fungus YN-7 strain. Before inoculation (0 h) and 8 h and 16 h after inoculation, the leaf sheaths of rice in sections 1 cm above and below the inoculation were cut and preserved in liquid nitrogen.

[0041] Following the instructions in the manufacturer's manual (Invitrogen), total RNA was extracted from each rice sample using Trizol. The total RNA was then digested with DNase I (RNase-free, Promega) to remove genomic DNA contamination (see the DNase I manual for the method). Subsequently, the total RNA was reverse transcribed into the first strand of cDNA using reverse transcriptase (TaKaRa) (see the reverse transcriptase manual for the method). The reaction conditions were: 37°C for 30 min; 85°C for 5 sec; 4°C for forever. Using cDNA as a template and the rice Actin gene as an internal reference gene (Actin gene amplification primers F1: 5'-CTTCATAGGAATGGAAGCTGCGGGTA-3' and R1: 5'-CGACCACCTTGATCTTCATGCTGCTA-3'), real-time quantitative PCR was performed using OsPP2Act gene-specific quantitative primers (qRT-PP2Act-F: 5'-GTCTATCTCTCATCTCAAGGGC-3' and qRT-PP2Act-R: 5'-CATGTTACCACAGCGATAACAG-3'). The reaction conditions were: pre-denaturation at 95℃ for 2 min, followed by the following cycles: 95℃ for 15 sec, 60℃ for 10 sec, and 72℃ for 10 sec, for a total of 40 cycles. The results showed that OsPP2Act was expressed in roots, stems, leaves, leaf sheaths, and panicles, with relatively high expression levels in leaves and leaf sheaths, consistent with the main sites affected by rice sheath blight. At 8 and 16 hours post-inoculation, the expression level of OsPP2Act increased in different rice varieties induced by the rice sheath blight pathogen, suggesting that OsPP2Act may be involved in the rice sheath blight defense response. Figure 1 ).

[0042] Example 3

[0043] Vector construction, genetic transformation and detection

[0044] 1. Steps for constructing a CRISPR / Cas9 knockout vector using the rice OsPP2Act gene:

[0045] (1) Select a knockout target site with high efficiency; design and synthesize an sgRNA that recognizes the target site using the CDS of the OsPP2Act gene in Example 1. The sequence of sgRNA is: 5'-CCTTCACGGTGGTCTCTCTCCAT-3'.

[0046] (2) The specific restriction endonuclease Pst1 (Takara) was used to cleave the pCXUN-Cas9 vector (Chinese Patent CN108949805A) and bind to the sgRNA. The reaction system was as follows: 4 μL of sgRNA; 2 μL of linearized vector template after enzyme digestion; 1 μL of recombinase (Exnase II from Novizan Biosciences); 2 μL of recombinant buffer (5×CEⅡBuffer from Novizan Biosciences); 1 μL of H2O. The PCR instrument was run at 37℃ for 30 min and then stored on ice.

[0047] (3) Transform DH5α. After the competent DH5α cells are dissolved, add the ligation product from the previous step and spread it on an LB plate containing kanamycin. Incubate at 37°C for 1 day.

[0048] (4) Randomly select 12 single clones from the plate and place them into 2mL sterile EP tubes. Add 500μL of liquid LB containing kanamycin beforehand, and shake for 6h. Take 5μL of bacterial culture from each sample for PCR reaction. Select positive clones and sequence them for verification. The primer sequences for the PCR reaction are as follows:

[0049] pp2act-ko-F:5'-TGTAAAACGAGCGGCCAGT-3',

[0050] pp2act-ko-R: 5'-ATGGAGAGAGACCACCGTGAAGG-3';

[0051] For the correct positive clone, extract the plasmid and use the EZNATM Plasmid Midi Kit (OMEGA) to extract the recombinant plasmid.

[0052] (5) The recombinant positive plasmid was transformed into Agrobacterium EHA105. The system consisted of 20 μl Agrobacterium (EHA105) + 1 μL plasmid. The mixture was incubated on ice for 5 min, then flash-frozen in liquid nitrogen for 5 min, then incubated in water at 37°C for 5 min, and finally incubated on ice for 5 min. 100 μl of antibiotic-free LB was added, and the mixture was shaken at 200 rpm for 2 h at 28°C. The mixture was then directly plated on a kanamycin + rifampin plate and incubated at 28°C for two days.

[0053] (6) Verification of positive Agrobacterium monoclonal samples: Two days later, pick one monoclonal sample and place it in a 5ml sterile EP tube. Add 2ml of the corresponding bacterial antibiotic + rifampin beforehand and shake overnight. The next day, send the bacterial culture for sequencing. After the sequencing results are correct, the prepared Agrobacterium pCXUN-Cas9-OsPP2Act can be used for subsequent transformation experiments.

[0054] Agrobacterium-mediated transformation of conventional japonica rice variety Dongjin callus was performed, followed by screening with hygromycin to obtain 16 stable T0 transgenic seedlings. Sequencing verification revealed two knockout transgenic lines, named ospp2act-1 and ospp2act-4, respectively. Figure 4 ), where ospp2act-1 has an inserted C base, and ospp2act-4 has a missing 5 bases.

[0055] 2. The construction steps of the overexpression vector are as follows:

[0056] Primers were designed using the CDS of the OsPP2Act gene from Example 1: OsPP2Act-CDS-F: 5'-ATGCCGTCGTCGCACGGG-3' and OsPP2Act-CDS-R: 5'-CAAAAAGTAGTCGGGAGTCT-3'. The gene was cloned using NIP cDNA as a template. The CDS sequence of OsPP2Act was obtained by amplification with high-fidelity DNA polymerase. Its nucleotide sequence is shown in SEQ ID NO.1, and its amino acid sequence is shown in SEQ ID NO.2. The PCR program was as follows: pre-denaturation: 95℃ for 5 min; denaturation: 95℃ for 30 s; annealing: 58℃ for 30 s; extension: 72℃ for 3 min; 37 cycles; total extension 5 min. The product was stored at 4℃ after the reaction.

[0057] (2) The overexpression vector pCAMBIA1390 (Liu Xiuming et al., Study on transgenic cephalosporin AD (CAD) gene in alfalfa [J]. Journal of South China Agricultural University, 2012, 33(04):498-502.) with strong promoter Ubi was linearized by restriction endonuclease PstI (Takara).

[0058] (3) The target gene and the linearized vector digested by enzyme digestion were ligated using homologous recombinase (Novizan ClonExpress II One Step Cloning Kit reagent).

[0059] (4) The ligation product was introduced into competent DH5α cells, and positive single clones were selected and sequenced on LB medium containing kanamycin. After verification, the OsPP2Act-OE vector construction was successful. The above plant expression vector was transformed into the rice variety Dongjin using the Agrobacterium-mediated transformation method. Six independent T0 generation transgenic plants were obtained by Western blotting and qRT-PCR (using the same primers as in Example 2). Two transgenic lines were selected and named OsPP2ActOE-2 and OsPP2ActOE-4. Figure 2 (As shown).

[0060] Example 4

[0061] Identification of sheath blight resistance in genetically modified rice

[0062] Resistance to sheath blight was identified in wild-type (WT), gene-edited knockout lines (ospp2act-1, ospp2act-4), and overexpression lines (OsPP2ActOE-2, OsPP2ActOE-4) of this gene using both greenhouse inoculation and in vitro inoculation methods.

[0063] The method for identifying resistance to greenhouse sheath blight is as follows:

[0064] When the rice plants reach the 3-leaf stage, transplant them into rectangular pots, 5 plants per pot, and place them in a greenhouse with 14 hours of light (30℃) and 10 hours of darkness (24℃), and use a misting system for humidification. Inoculate the rice plants when they reach the early booting stage. Before inoculation, prune any naturally diseased or dead plants, as well as any small or excessive tillers. The inoculation method is manual embedding. Carefully place a 1cm long and 2mm wide piece of bark (covered with mycelium) containing *Rhizoctonia solani* hyphae into the leaf sheath 1cm below the second leaf from the bottom. Inoculate 5 seedlings per pot, and inoculate 5 stems from the same growth stage on each seedling. Inspect the length of lesions 14 days after inoculation.

[0065] The method for identifying resistance to in vitro sheath blight is as follows:

[0066] When rice plants in the field reached the early heading stage, detached stem samples were taken. The rice stems were cut off, leaving only the flag leaf and the second leaf from the top. The samples were then placed in water overnight to allow the rice to acclimate to the climatic chamber environment and prevent water loss. The next day, inoculation was performed using the same embedding method. A 1cm long and 2mm wide piece of bark (covered with mycelium) was carefully placed 1cm below the leaf sheath of the second leaf from the top. After inoculation, the stems were inserted into test tube racks containing floral foam and then transferred to a nutrient solution. The plants were then placed in an environment with 14 hours of light (30℃), 10 hours of darkness (24℃), and 90% humidity. The length of lesions was assessed 7 days after inoculation.

[0067] When using artificial inoculation in a greenhouse, such as Figure 3 and Figure 4 The average lesion length of the two transgenic overexpression lines shown (23.40 cm and 23.59 cm, respectively) was significantly longer than that of the wild type (20.09 cm). Figure 3 The average lesion length of the two gene-edited lines (15.24 cm and 15.81 cm, respectively) was significantly shorter than that of the wild type (20.09 cm). Figure 4 ).

[0068] When using in vitro inoculation, such as Figure 5 and Figure 6 The average lesion length of the two transgenic overexpression lines (15.37 cm and 15.31 cm, respectively) was significantly longer than that of the wild type (12.65 cm). Figure 5 The average lesion length of the two gene-edited lines (10.69 cm and 8.95 cm, respectively) was significantly shorter than that of the wild type (12.65 cm). Figure 6 These results indicate that the gene OsPP2Act negatively regulates rice sheath blight resistance, and that rice's resistance to sheath blight can be significantly enhanced through gene editing.

Claims

1. The application of the OsPP2Act gene in regulating rice resistance to sheath blight, characterized by: The nucleotide sequence of the OsPP2Act gene is shown in SEQ ID NO.1, and the amino acid sequence of the protein encoded by the OsPP2Act gene is shown in SEQ ID NO.

2. Overexpression of the OsPP2Act gene reduces rice resistance to sheath blight, while knocking out the gene enhances rice resistance to sheath blight. The length of sheath blight lesions in transgenic overexpression lines is significantly higher than that in wild-type lines, while the length of sheath blight lesions in gene-edited knockout lines is significantly lower than that in wild-type lines. The rice varieties mentioned are Dongjin, Nipponbare, YSBR1, Minghui 63, Chenghui 727, Yangdao 6, and Taijing 394.

2. The application of the OsPP2Act protein encoded by the OsPP2Act gene in regulating resistance to rice sheath blight, characterized by: The OsPP2Act protein is encoded by the OsPP2Act gene, the nucleotide sequence of which is shown in SEQ ID NO.1, and the amino acid sequence of the OsPP2Act protein encoded by the OsPP2Act gene is shown in SEQ ID NO.

2. Overexpression of the OsPP2Act gene reduces rice resistance to sheath blight, while knocking out the gene enhances rice resistance to sheath blight. The sheath blight lesion length of transgenic overexpression lines is significantly higher than that of wild type, while the sheath blight lesion length of gene-edited knockout lines is significantly lower than that of wild type. The rice varieties mentioned are Dongjin, Nipponbare, YSBR1, Minghui 63, Chenghui 727, Yangdao 6, and Taijing 394.

3. The application of a recombinant vector, recombinant microorganism, or transgenic plant cell line containing the OsPP2Act gene in regulating resistance to rice sheath blight, characterized in that: The nucleotide sequence of the OsPP2Act gene is shown in SEQ ID NO.1, and the amino acid sequence of the protein encoded by the OsPP2Act gene is shown in SEQ ID NO.

2. Overexpression of the OsPP2Act gene reduces rice resistance to sheath blight, while knocking out the gene enhances rice resistance to sheath blight. The length of sheath blight lesions in transgenic overexpression lines is significantly higher than that in wild-type lines, while the length of sheath blight lesions in gene-edited knockout lines is significantly lower than that in wild-type lines. The rice varieties mentioned are Dongjin, Nipponbare, YSBR1, Minghui 63, Chenghui 727, Yangdao 6, and Taijing 394.

4. The application of an OsPP2Act gene or OsPP2Act protein, or the recombinant vector, recombinant microorganism, or transgenic plant cell line as described in claim 3, in the cultivation of transgenic rice with enhanced resistance to sheath blight, characterized in that: The nucleotide sequence of the OsPP2Act gene is shown in SEQ ID NO.1, and the amino acid sequence of the protein encoded by the OsPP2Act gene is shown in SEQ ID NO.

2. Overexpression of the OsPP2Act gene reduces rice resistance to sheath blight, while knocking out the gene enhances rice resistance to sheath blight. The length of sheath blight lesions in transgenic overexpression lines is significantly higher than that in wild-type lines, while the length of sheath blight lesions in gene-edited knockout lines is significantly lower than that in wild-type lines. The rice varieties mentioned are Dongjin, Nipponbare, YSBR1, Minghui 63, Chenghui 727, Yangdao 6, and Taijing 394.

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