Application and method for inducing synthesis of secondary cell wall of thick-wall tissue of rice leaf sheath and expression of phenolic polymer in improving resistance of rice to brown planthopper

Abstract

The invention provides application and a method for inducing synthesis of a secondary cell wall of a rice leaf sheath thick-wall tissue and expression of a phenolic polymer in improving resistance of rice to brown planthopper, and belongs to the technical field of gene engineering. Chemical elicitors are utilized to excite rice in different growth periods to induce synthesis of cell walls in rice leaf sheaths and expression of phenolic polymers, so that resistance to brown planthoppers is generated; the chemical exciton is trifluorobenzene pyrimidine; the base sequences of the genome I participating in the synthesis of the rice leaf sheath cell wall are respectively as shown in SEQ ID NO: 7 to SEQ ID NO: 24; the phenolic polymer is formed by consuming flavonoid by peroxidase by taking hydrogen peroxide as an electron acceptor; the base sequences of the genome II participating in peroxidase expression are respectively shown as SEQ ID NO: 25 to SEQ ID NO: 42.

Description

Technical Field

[0001] The invention relates to an application and method of inducing secondary cell wall synthesis of rice sheath sclerenchyma tissue and expression of phenolic polymers in improving rice resistance to brown planthoppers, belonging to the technical field of genetic engineering. Background Art

[0002] Brown planthopper is one of the important pests in rice production. Traditional chemical control methods are often accompanied by the risk of environmental pollution and increased resistance of pests. As a piercing-sucking insect, brown planthopper uses its stylet to pierce the phloem tissue of plants and absorb sap nutrients. Stylet is an organ that pierces and absorbs sap from the phloem of plants. In order to absorb the sap from the rice phloem, the stylet of brown planthopper must pass through the sclerenchyma and parenchyma of rice leaf sheaths before reaching the phloem. Sclerenchyma refers to the part composed of multiple thickened and hardened cell layers. It is mainly composed of polysaccharides such as leaf sheath cellulose, hemicellulose, lignin and pectin. The cell walls of sclerenchyma cells are thicker and contain a higher proportion of cellulose and a lower proportion of cytoplasm, which gives the cells greater mechanical strength. In sclerenchyma, cells are usually closely arranged with small intercellular spaces, and their cell walls are tightly connected to form a strong structure. The thickening and hardening of the sclerenchyma cell walls help prevent the penetration of the stylets of piercing-sucking insects such as brown planthoppers, thereby protecting the internal tissues of plants such as phloem from damage. Therefore, the thickened sclerenchyma provides an effective physical defense barrier for the plant, hindering the brown planthopper's mouth needle from piercing into the phloem to feed. In the plant body, peroxidase and hydrogen peroxide react with flavonoids to form phenolic polymers in the leaf sheath. These polymers, as a physical barrier, can hinder the feeding of pests with piercing-sucking mouthparts (such as white-backed planthoppers, brown planthoppers, etc.), thereby enhancing the resistance of rice to piercing-sucking mouthparts pests. However, in the prior art, there are few reports on methods for increasing the expression of plant leaf sheath sclerenchyma and the aggregation of phenolic polymers by induction. Therefore, there is an urgent need for a method to increase the synthesis of secondary cell walls and the expression of phenolic polymers in rice leaf sheath sclerenchyma by induction, so as to further improve the resistance of plants to pests with piercing-sucking mouthparts. Summary of the invention

[0003] In order to solve the above-mentioned defects and shortcomings in the prior art, the present invention provides an application and method of inducing the synthesis of secondary cell walls of rice leaf sheath sclerenchyma and the expression of phenolic polymers in improving the resistance of rice to brown planthoppers. Rice is stimulated at different growth stages to increase the synthesis of secondary cell walls of rice leaf sheath sclerenchyma and the expression of phenolic polymers, so as to improve the resistance of rice to brown planthoppers throughout the entire growth period.

[0004] To solve the above technical problems: The first object of the present invention is to provide an application of inducing the synthesis of secondary cell walls of rice leaf sheath sclerenchyma tissue and the expression of phenolic polymers in improving the resistance of rice to brown planthoppers, using chemical elicitors to stimulate rice at different growth stages to induce the synthesis of secondary cell walls of rice leaf sheath sclerenchyma tissue and the expression of phenolic polymers, thereby producing resistance to brown planthoppers; The chemical elicitor is trifluorophenylpyrimidine; The genome I involved in rice sheath cell wall synthesis includes OsBC15 , OsCESA3 , OsCESA4 , OsCESA6 , OsCESA7 , OsCESA8 , OsCESA9 , OsCSLF2 , OsCSLH1 , OsIRX9 , OsIRX10 , OsIRX14 , OsTBL8 , OsCslF8 , OsCslE1 , OsCSLF6 , OsCslE6 and OsCesA1 , whose base sequences are shown in SEQ ID NO:7 to SEQ ID NO:24 respectively; Phenolic polymers are formed by peroxidases using hydrogen peroxide as an electron acceptor to consume flavonoids. The gene set II involved in the expression of phenolic polymers in rice leaf sheaths includes PRX41 , PRX45 , Os1bglu2 , prx138 , prx65 , prx115 , prx32 , CYP84A5 , OsHCT2 , prx75 , prx26 , prx117 , Os03g0749500 , prx77 , Os9bglu33 , poxA , OsCCR17 and OsPOD , and their base sequences are shown in SEQ ID NO:25 to SEQ ID NO:42, respectively.

[0005] Furthermore, different growth stages of rice include sowing stage and heading stage; among them, the sowing stage excitation treatment is used to induce and increase the synthesis of secondary cell walls in the thick wall tissue of rice sheaths; the heading stage excitation treatment is used to induce and increase the expression of phenolic polymers in rice sheaths.

[0006] The second object of the present invention is to provide a method for improving the resistance of rice to brown planthoppers, comprising the following steps: Using chemical elicitors to treat rice seeds, improve the synthesis of secondary cell walls in rice leaf sheath thick wall tissue, and promote rice resistance to brown planthoppers during the seedling stage to tillering stage; or / and using chemical elicitors to spray stems and leaves, increase the expression of phenolic polymers in rice leaf sheaths, and promote rice resistance to brown planthoppers during the heading stage; the chemical elicitor is triflupromide; The genome I involved in the synthesis of secondary cell walls in the thick wall tissue of rice sheaths includes OsBC15 , OsCESA3 , OsCESA4 , OsCESA6 , OsCESA7 , OsCESA8 , OsCESA9 , OsCSLF2 , OsCSLH1 , OsIRX9 , OsIRX10 , OsIRX14 , OsTBL8 , OsCslF8 , OsCslE1 , OsCSLF6 , OsCslE6 and OsCesA1 , whose base sequences are shown in SEQ ID NO:7 to SEQ ID NO:24 respectively; Phenolic polymers are formed by peroxidases using hydrogen peroxide as an electron acceptor, consuming flavonoids; Gene set II involved in peroxidase expression includes PRX41 , PRX45 , Os1bglu2 , prx138 , prx65 , prx115 , prx32 , CYP84A5 , OsHCT2 , prx75 , prx26 , prx117 , Os03g0749500 , prx77 , Os9bglu33 , poxA , OsCCR17 and OsPOD , and their base sequences are shown in SEQ ID NO:25 to SEQ ID NO:42, respectively.

[0007] Furthermore, the specific process of inducing rice resistance to brown planthoppers by dressing seeds with triflubenzuron is as follows: S1.1 Soak the rice seeds for 48 hours and then dry them in the shade for 12 hours; S1.2 The triflubenzuron and rice were stirred and mixed in a seed mixer for 10 min to obtain treated rice seeds. The mass ratio of triflubenzuron to rice seeds was (0.5-6) ​​g: 1 kg; S1.3 The treated rice seeds were sown in seedling trays and transplanted to the field after 25 days.

[0008] The specific process of inducing rice resistance to brown planthoppers by spraying triflumuron on stems and leaves is as follows: For rice seedlings at the heading stage, a diluted solution of triflumuron was used for stem and leaf spraying. The dosage of triflumuron was 7.5 to 90 g of active ingredient per hectare.

[0009] Preparation process of triflumuron dilution: 10% triflumuron suspension, add water to prepare triflumuron dilution with a concentration of 100~10000ppb.

[0010] The beneficial technical effects achieved by the present invention are as follows: the present invention provides an application and method of inducing the synthesis of secondary cell walls of rice sheath sclerenchyma and the expression of phenolic polymers in improving the resistance of rice to brown planthoppers, and carries out resistance stimulation and induction on rice at different growth stages, thereby increasing the high expression of secondary cell walls of rice sheath sclerenchyma and phenolic polymer-related substances, increasing the synthesis of sheath cell walls and the formation of phenolic polymers that resist brown planthoppers, further improving the resistance of rice to brown planthoppers throughout the growth period, and reducing the use of chemical agents. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 Statistical diagrams of different components in rice after 30 and 60 days of growth after seed dressing treatment according to Example 1 of the present invention; wherein 1A to 1C are the test results of cellulose, hemicellulose, lignin and sclerenchyma in rice leaf sheaths after 30 days of growth, and 1D to 1F are the test results of cellulose, hemicellulose, lignin and sclerenchyma in rice leaf sheaths after 60 days of growth; Figure 2 The results of rice sclerenchyma detection after 30 and 60 days of growth after the seed dressing treatment of Example 1 of the present invention, wherein 2A is a microscope picture, 2B and 2C are statistical results of sclerenchyma thickness and sclerenchyma cell wall thickness at 30 days, and 2D and 2E are statistical results of sclerenchyma thickness and sclerenchyma cell wall thickness at 60 days; Figure 3 After the triflubenzuron seed dressing treatment of Example 1 of the present invention, the cross-section of the rice leaf sheath was stained and photographed with a laser confocal microscope after 30 days and 60 days of growth; Figure 4 The results of the detection of the content of metabolites in rice sheaths after 60 days of growth after the triflubenzuron seed dressing treatment in Example 1 of the present invention, wherein 4A to 4H are the statistical contents of peroxidase, apigenin, genistein, genistin, hydrogen peroxide, cohenin, naringenin and naringenin, respectively; Figure 5The survival rate statistics of brown planthoppers on rice seedlings grown for 30 days and 60 days after the trifluanid seed dressing treatment in Example 1 of the present invention are shown in Figure 5A, which are the statistical data for 30 days and 5B, which are the statistical data for 60 days. Figure 6 The residual amount of trifluanid in rice leaf sheaths at different growth stages after the trifluanid seed dressing treatment according to Example 1 of the present invention is detected; Figure 7 The results of the stomach toxicity test and contact toxicity test of rice sheath extract on brown planthopper after 30 and 60 days of growth after the triflubenzuron seed dressing treatment in Example 1 of the present invention are shown in Figures 7A and 7B, respectively, are the stomach toxicity test results of rice sheath extract on brown planthopper after 30 and 60 days of growth, and 7C and 7D are the contact toxicity test results of rice sheath extract on brown planthopper after 30 and 60 days of growth, respectively; Figure 8 This is a picture of the thick wall tissue after spraying triflubenzuron on stems and leaves in Example 2 of the present invention; Fig. 9 These are pictures of leaf sheath phenolic polymer detection 30 days, 45 days, and 60 days after rice was sprayed with different concentrations of trifluanid on stems and leaves in Example 2 of the present invention; Fig.10 The statistical results of the survival rates of brown planthoppers on rice seedlings grown for 30 days and 60 days after seed dressing with different concentrations of triflupromide in Example 3 of the present invention are shown, wherein 10A is the statistical data for 30 days, and 10B is the statistical data for 60 days; Fig.11 The expression level of the genome I involved in the synthesis of secondary cell walls of leaf sheath sclerenchyma tissue of rice grown for 30 days after the seed dressing treatment in Example 1 of the present invention; Fig.12 This is the expression level of genome II involved in the synthesis of secondary cell walls of leaf sheath sclerenchyma tissue in rice grown for 60 days after the seed dressing treatment of Example 1 of the present invention. DETAILED DESCRIPTION

[0012] The present invention will be further described below in conjunction with specific examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention.

[0013] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0014] Example 1: Seed dressing with triflubenzuron improves rice resistance to brown planthopper According to the ratio of 2.0 g of effective dose of triflubenzuron per 1 kg of rice seeds, triflubenzuron and rice seeds were mixed evenly and sown; the seeds were mixed with water as the control group. Including: Control group 1: rice grown to 30 days without seed dressing; Control group 2: rice grown to 60 days without seed dressing; Experimental group 1: rice grown to 30 days after seed dressing with trifluanid; Experimental group 2: Rice grown to 60 days after seed dressing with triflubenzuron. Total RNA was extracted from rice leaf sheaths of the above different groups according to the operation method of SteadyPure Plant RNA Extraction Kit (Accurate Biology, Hunan, China). Sequencing was performed on the Illumina NovaSeq high-throughput sequencing platform. The BENAGEN platform (Wuhan, China) was used to analyze the RNA. https: / / www.benagen.com ) The sequencing results were analyzed, and the results are shown in Table 1. Fig.11 and Fig.12 Leaf sheaths of three rice plants were collected for each biological replicate, and each treatment was repeated three times.

[0015] From Table 1 and Fig.11 It can be seen that after the chemical elicitor triflupromide induction treatment, the expression levels of genes involved in the synthesis of secondary cell walls in the thick wall tissue of the leaf sheath of rice increased after 30 days, especially OsCSLF2 , OsTBL8 and OsCslF8 , the expression levels increased by more than 1.5 times. Table 1

[0016] 1. Detection of different components of leaf sheath tissue: Leaf sheath tissue was collected at 30 days and 60 days after rice sowing, and the contents of cellulose, hemicellulose and lignin in the leaf sheath were detected respectively. The detection process is as follows: 1.1. Determination of plant cellulose content: Cellulose was extracted using a cellulose determination kit (BC4280, Solarbio Science & Technology Co., Ltd.) according to the instructions, and its absorbance at 620 nm was detected by visible light spectroscopy. 1.2. Detection of hemicellulose: Hemicellulose was extracted from rice leaf sheath samples that were dried and ground into powder using a hemicellulose determination kit (BC4440, Solarbio Science & Technology Co., Ltd.) according to the instructions. Its absorbance at 540 nm was detected. 1.3. Detection of lignin: The determination of lignin content was performed using a microplate kit (D799081-0100, Sangon Biotech) according to the instructions. The rice leaf sheath samples that were dried and ground into powder were acetylated and converted into a form that can be quantified by spectrometry. The absorbance at 280 nm was measured using a UV-visible spectrometer.

[0017] The results are as follows Figure 1 As shown: Compared with the control group, the contents of cellulose, hemicellulose and lignin in rice leaf sheaths were significantly increased 30 and 60 days after seed dressing with triflupromide. These substances are the main components of thick wall tissue, indicating that triflupromide seed dressing induced the expression of these substances.

[0018] 2. Detection of thick wall tissue: embed the leaf sheath tissue in paraffin, slice it, dewax it and then stain it. Observe the leaf sheath tissue under a microscope and measure the thickness of the thick wall tissue. Figure 2 As shown: Compared with the control group, the thickness of the sclerenchyma and the thickness of the cell wall of the sclerenchyma increased significantly 30 days after seed dressing. The thickness of the cell wall of the sclerenchyma also increased significantly 60 days after seed dressing.

[0019] 3. Detection of phenolic polymers in leaf sheaths: The aggregation of phenolic polymers in the thin wall tissue of leaf sheaths was observed by laser confocal microscopy. Figure 3 and Figure 4 As shown: No particles were produced 30 days after seed dressing, but obvious particles were produced in the rice leaf sheaths at 60 days. Compared with the control group, the peroxidase content in the rice leaf sheaths increased, the hydrogen peroxide content decreased, and the content of the six flavonoids decreased 60 days after seed dressing with triflubenzuron. Fig.12 It can be further seen from Table 1 that for 60-day-old rice, the expression of peroxidase in the leaf sheath increased significantly, e.g. PRX45 The gene expression level increased by 9.45 times. Figure 3 and Figure 4 Based on the results, it can be inferred that peroxidase in rice sheath uses hydrogen peroxide as an electron acceptor to consume flavonoids to form phenolic polymers, thereby inducing physical resistance of rice to brown planthoppers.

[0020] 4. Statistics of survival rate of brown planthoppers: Cover the rice seedlings with glass cylinders, select third-instar brown planthopper nymphs to feed on the rice seedlings, and release 60 third-instar brown planthopper nymphs into each cylinder. Record the number of surviving brown planthopper nymphs in each cylinder every day, and calculate the survival rate of brown planthoppers. Figure 5 As shown, treatment with trifluanid significantly reduced the survival of brown planthoppers in rice seedlings 30 days after seed dressing.

[0021] 5. Toxicity elimination experiment of triflufenazine residues in rice to brown planthoppers: In order to eliminate the toxicity of triflufenazine residues in rice to brown planthoppers, 0.5 g ai kg -1 , 1 g ai kg -1 , 1.5 g ai kg -1 , 2.0 ga.i. kg -1The rice seedlings planted in the field were sprayed with trifluanid and the residual amount of trifluanid in the leaf sheath was tested when the rice was grown to 30 days and 60 days: The rice seedlings planted in the field were sprayed with trifluanid, and the level of trifluanid during the entire growth period of rice (from 3 days after sowing to 120 days) was tested. The rice leaf sheath tissues in the field were randomly collected as test samples. The samples were first dried at 50°C for 12 hours and then crushed using a crusher (model: RS-FS150, Royalstar). 0.5 g of the crushed sample was mixed with 20 mL of 60% acetonitrile, incubated in a 50°C water bath for 30 minutes, and then centrifuged at 6,000 rpm for 5 minutes. 1 mL of the supernatant was collected, dried under a nitrogen stream, re-dissolved in 60% acetonitrile, and filtered through a 13 mm × 0.22 μm polyvinylidene fluoride syringe filter. The filtrate was the sample to be tested, which was transferred to a sample bottle for ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS) analysis. The specific process was as follows: 1 μL of the sample solution to be tested was injected into an Agilent Eclipse Plus C18 column (2.1×50 mm inner diameter, 1.7 μm), and the column temperature was maintained at 40°C. The mobile phase consisted of solvent A (0.1% formic acid solution) and solvent B (acetonitrile) with a flow rate of 0.2 mL / min. The UPLC analysis used a gradient elution program as follows: 0-1 min, 95% A; 1-4.5 min, linear gradient from 95% to 10% A; 4.5-6 min, 10% A; 6-6.1 min, linear gradient from 10% to 95% A; 6.1-10 min, 95% A. The analysis was performed in positive ion multiple reaction monitoring mode. The specific fragment ion mass-to-charge ratio (m / z) values ​​monitored were 399.0 / 121.0 and 399.0 / 287.9. Declustering potential and collision energy were set to 80 V and 25 V, respectively. Mass spectra were recorded on an AB Sciex 4500 instrument operating in positive ion mode with an electrospray ion source. The system was controlled and data were acquired by MultiQuant 3.0.2 software (AB Sciex Co.). Triflubenzuron standards were obtained from Jiangsu Agricultural Product Quality Inspection Center (Jiangsu Academy of Agricultural Sciences, China). UPLC analysis was performed using an Agilent 1290 UPLC system. The results of the detection of triflubenzuron residues in rice are shown in Figure 2. Figure 6 As shown. Figure 6 It can be seen that: 0.5~2.0 g ai kg -1 After the rice was treated with the same dose of trifluanid, the residue in the leaf sheath dropped to 60.3-234.6 ppb when the rice grew to 30 days old. 50The values ​​are generally 500-1644 ppb. This indicates that the residues of triflubenzuron in rice seeds are not enough to cause the mortality difference of brown planthoppers or even other planthoppers during the growth period of 30 days and beyond after the rice seeds are treated with triflubenzuron.

[0022] The concentration was 2.0 g ai kg -1 0.1 g of rice leaf sheath tissue samples grown to 30 / 60 days in the triflubenzuron seed dressing treatment and the control group were mixed and extracted with 1 mL of methanol. The samples were vortexed for 5 minutes and ultrasonically extracted for 20 minutes. Then, they were centrifuged at 4°C and 12,000 rpm for 20 minutes. The supernatant was collected and concentrated to 50 μL, and added to artificial feed at a final concentration of 50 μL / mL for stomach toxicity test and contact toxicity test.

[0023] 5.1. Stomach poison test: Add the above triflubenzuron methanol extract to the artificial diet of brown planthoppers. The preparation method of artificial diet is the existing technical formula and will not be repeated here. Use a glass tube with a diameter of 2 cm and a length of 9 cm, put 15 3rd-instar rice planthopper nymphs, seal the tube mouth with a sealing film, and drip 200 μL of artificial diet containing methanol extract on the outside of the first layer of sealing film. Change it every day and monitor the survival number of brown planthoppers for 7 days. Calculate the survival rate. The results are as follows: Figure 7 7A and 7B.

[0024] 5.2. Contact test: 40 3rd-instar brown planthopper nymphs were placed in each culture dish (12 cm in diameter, 2.5 cm in height). The inside of the culture dish was lined with filter paper soaked with different methanol extracts. After continuous exposure for 2 hours, the nymphs were transferred to healthy rice seedlings, with 15 nymphs placed on each plant. The survival rate of brown planthoppers was monitored and recorded every day for 7 days. The results are as follows: Figure 7 7C and 7D in FIG.

[0025] from Figure 7 It can be seen that compared with the methanol control group, the rice methanol extract group 30 days and 60 days after triflubenzuron seed dressing and the rice methanol extract group in the control group had no significant effect on the survival rate of brown planthoppers. Therefore, it shows that the residual amount of triflubenzuron on rice is not enough to cause lethality to brown planthoppers.

[0026] In summary, seed dressing treatment with triflubenzuron can induce the thickening of the sclerenchyma in the rice leaf sheath and the aggregation of phenolic polymers, reducing the survival rate of brown planthoppers feeding on rice seedlings, thereby improving resistance to brown planthoppers.

[0027] Example 2: Spraying triflufenazine on stems and leaves improves rice resistance to brown planthoppers The rice plants without seed treatment were sprayed with 100, 500, 1000, and 10000 ppb of trifluanid on their stems and leaves for 10 and 30 days. When the rice seedlings grew to 30 and 60 days, the leaf sheath tissues were collected for paraffin embedding, sectioning, dewaxing, and staining. The leaf sheath tissues were observed under a microscope and the thickness of the sclerenchyma was measured. Figure 8 As shown, the thick wall tissue of rice leaf sheath was significantly thickened after spraying trifluanid on stems and leaves.

[0028] Rice seedlings grown for 30, 45, and 60 days without seed treatment were selected, and trifluanid was sprayed on the stems and leaves. After 30 days, the aggregation of phenolic polymers in the leaf sheath parenchyma was observed using a laser confocal microscope. Fig. 9 As shown in the figure, when the concentration of trifluanid was 100 ppb, it was found that the particles in the rice sheath tissue were obviously aggregated. With the increase of trifluanid concentration, the degree of particle aggregation became more and more obvious.

[0029] Example 3 Effect of the dosage of triflufenazine for seed dressing on improving rice resistance to brown planthopper Rice seeds were treated with triflubenzuron (g) / rice seeds (kg) at the following dosages: 0.5 g / kg, 1.0 g / kg, 1.5 g / kg, 2 g / kg, 3 g / kg, 4.5 g / kg, and 6 g / kg. When the rice grew to 30 and 60 days, third-instar brown planthopper nymphs were selected to feed on rice seedlings. The nymphs were covered with glass cylinders, and 30 third-instar brown planthopper nymphs were released in each cylinder. The number of surviving brown planthopper nymphs in each cylinder was recorded every day, and the survival rate of brown planthoppers was calculated. The results are as follows: Fig.10 As shown in the data, the survival rate of brown planthoppers in rice treated with seed dressing decreased significantly after 30 and 60 days of growth, and with the increase of the dosage of trifluanid seed dressing, the survival rate of brown planthoppers gradually decreased, that is, the dosage of trifluanid seed dressing was positively correlated with the brown planthopper resistance of rice.

[0030] The present invention has been disclosed above with preferred embodiments, but they are not intended to limit the present invention. Any technical solutions obtained by adopting equivalent replacement or equivalent transformation solutions fall within the protection scope of the present invention.

Claims

1. Application of inducing secondary cell wall synthesis and phenolic polymer expression in rice sheath sclerenchyma to improve rice resistance to brown planthopper, characterized in that: Chemical elicitors were used to stimulate rice at different growth stages to induce the synthesis of secondary cell walls in the thick wall tissue of rice sheaths and the expression of phenolic polymers, thereby producing resistance to brown planthoppers. The chemical elicitor is trifluorophenylpyrimidine; The genome I involved in the synthesis of secondary cell walls in the thick wall tissue of rice sheaths includes OsBC15 , OsCESA3 , OsCESA4 , OsCESA6 , OsCESA7 , OsCESA8 , OsCESA9 , OsCSLF2 , OsCSLH1 , OsIRX9 , OsIRX10 , OsIRX14 , OsTBL8 , OsCslF8 , OsCslE1 , OsCSLF6 , OsCslE6 and OsCesA1 , whose base sequences are shown in SEQ ID NO:7 to SEQ ID NO:24 respectively; Phenolic polymers are formed by peroxidases using hydrogen peroxide as an electron acceptor, consuming flavonoids; Gene set II involved in peroxidase expression includes PRX41 , PRX45 , Os1bglu2 , prx138 , prx65 , prx115 , prx32 , CYP84A5 , OsHCT2 , prx75 , prx26 , prx117 , Os03g0749500 , prx77 , Os9bglu33 , poxA , OsCCR17 and OsPOD , and their base sequences are shown in SEQ ID NO:25 to SEQ ID NO:42, respectively.

2. The use according to claim 1, characterized in that: The different growth stages of rice include the sowing stage and the heading stage; the sowing stage stimulation treatment is used to induce and increase the synthesis of secondary cell walls of the thick wall tissue of the rice sheath; the heading stage stimulation treatment is used to induce and increase the expression of phenolic polymers in the rice sheath.

3. A method for improving rice resistance to brown planthoppers, characterized in that The following steps are involved: Using chemical elicitors to treat rice seeds, improve the synthesis of secondary cell walls in rice leaf sheath thick wall tissue, and promote rice resistance to brown planthoppers during the seedling stage to tillering stage; or / and using chemical elicitors to spray stems and leaves, increase the expression of phenolic polymers in rice leaf sheaths, and promote rice resistance to brown planthoppers during the heading stage; the chemical elicitor is triflupromide; The genome I involved in rice sheath cell wall synthesis includes OsBC15 , OsCESA3 , OsCESA4 , OsCESA6 , OsCESA7 , OsCESA8 , OsCESA9 , OsCSLF2 , OsCSLH1 , OsIRX9 , OsIRX10 , OsIRX14 , OsTBL8 , OsCslF8 , OsCslE1 , OsCSLF6 , OsCslE6 and OsCesA1, The base sequences thereof are shown in SEQ ID NO:7 to SEQ ID NO:24 respectively; Phenolic polymers are formed by peroxidases using hydrogen peroxide as an electron acceptor, consuming flavonoids; Gene set II involved in peroxidase expression includes PRX41 , PRX45 , Os1bglu2 , prx138 , prx65 , prx115 , prx32 , CYP84A5 , OsHCT2 , prx75 , prx26 , prx117 , Os03g0749500 , prx77 , Os9bglu33 , poxA , OsCCR17 and OsPOD , and their base sequences are shown in SEQ ID NO:25 to SEQ ID NO:42, respectively.

4. The method according to claim 3, characterized in that: The specific process of inducing rice resistance to brown planthoppers by dressing seeds with triflumuron is as follows: S1.1 Soak the rice seeds for 48 hours and then dry them in the shade for 12 hours; S1.2 The triflubenzuron and rice were stirred and mixed in a seed mixer for 10 min to obtain treated rice seeds. The mass ratio of triflubenzuron to rice seeds was (0.5-6) ​​g: 1 kg; S1.3 The treated rice seeds were sown in seedling trays and transplanted to the field after 25 days.

5. The method according to claim 3, characterized in that: The specific process of inducing rice resistance to brown planthoppers by spraying triflumuron with stems and leaves is as follows: For rice seedlings at the heading stage, a diluted solution of triflumuron was used for stem and leaf spraying. The dosage of triflumuron was 7.5 to 90 g of active ingredient per hectare.

6. The method according to claim 5, characterized in that: Preparation process of triflumuron dilution: 10% triflumuron suspension, add water to prepare triflumuron dilution with a concentration of 100~10000 ppb.

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