Brown planthopper nlp21 protein and its coding gene in regulating plant resistance to brown planthopper

Abstract

This invention provides the application of the NlP21 protein and its encoding gene in regulating plant resistance to brown planthoppers, belonging to the field of genetic engineering technology. This invention provides the sequence of the NlP21 protein and its encoding gene in brown planthoppers. This gene is of great significance for regulating plant resistance to brown planthoppers and regulating the growth of brown planthoppers. Inhibiting the expression of the NlP21 gene in brown planthoppers can effectively reduce their survival ability, while overexpressing the NlP21 gene in plants can effectively improve plant resistance to brown planthoppers. The NlP21 protein and its encoding gene provided by this invention have excellent application prospects and significant application value for reducing pesticide use, maintaining ecological balance, and promoting sustainable development.

Description

Technical Field

[0001] This invention relates to the field of genetic engineering technology, specifically to the application of the NlP21 protein of brown planthopper and its encoding gene in regulating plant resistance to brown planthopper. Background Technology

[0002] Brown planthoppers are highly contagious and destructive migratory pests that migrate long distances. They typically congregate at the base of rice plants, sucking sap and causing the plants to wilt and die, leading to reduced yields or even total crop failure. This severely impacts rice production and quality, making it the leading pest in rice cultivation. Brown planthoppers cause approximately 1 to 1.5 billion kilograms of rice yield loss annually, equivalent to billions of yuan in economic losses. Currently, insecticides are commonly used to control brown planthoppers. However, the long-term excessive use of chemical insecticides not only worsens the environment but also produces pesticide residues, seriously endangering human health and causing severe environmental pollution. Therefore, actively developing and applying biological control technologies for brown planthoppers is of great significance for the scientific and effective control of their damage and for ensuring food and environmental safety.

[0003] RNA interference (RNAi) is a molecular biological phenomenon characterized by gene silencing induced by double-stranded RNA (dsRNA). Because RNAi technology can specifically knock out or shut down the expression of specific genes, it has been widely used in gene function research and disease treatment. Since its discovery, RNAi technology has developed rapidly and is now widely used in insect gene research. Microinjection is a method of injecting in vitro synthesized dsRNA into specific sites on insects using a microinjection apparatus. Microinjection is one of the most commonly used introduction methods, offering the advantage of precise control over the injection volume. It allows for specific observation of the effects of reduced expression levels of specific genes on the brown planthopper, greatly aiding theoretical research on gene function. Its application in brown planthopper gene research is of significant importance for ensuring my country's food and environmental security. Summary of the Invention

[0004] To address the shortcomings of the existing technologies, this invention provides the application of the brown planthopper NlP21 protein and its encoding gene in regulating plant resistance to brown planthopper.

[0005] To achieve the above objectives, the specific technical solution of the present invention is as follows:

[0006] In a first aspect, the present invention provides the application of the brown planthopper NlP21 protein or its encoding gene or a repressor of the encoding gene of the brown planthopper NlP21 protein in regulating plant resistance to brown planthopper, wherein the amino acid sequence of the NlP21 protein is (a) or (b):

[0007] (a) The amino acid sequence shown in SEQ ID NO. 1;

[0008] (b) An amino acid sequence of SEQ ID NO. 1 that has been substituted, deleted and / or added with one or more amino acids, and that has the same function as a protein composed of the amino acid sequence of SEQ ID NO. 1;

[0009] The gene encoding the NlP21 protein includes the nucleotide sequence shown in SEQ ID NO. 2; or, it includes a nucleotide sequence that expresses the same protein as the nucleotide sequence shown in SEQ ID NO. 2 by substitution, deletion and / or addition of one or more nucleotides.

[0010] Furthermore, the method of enhancing plant resistance to brown planthoppers involves overexpressing the gene encoding the NlP21 protein of the brown planthopper in the plant.

[0011] Secondly, the present invention provides the application of a repressor of the gene encoding the NlP21 protein of the brown planthopper in inhibiting the growth of the brown planthopper, wherein the repressor of the gene encoding the NlP21 protein of the brown planthopper is a dsRNA capable of inhibiting the expression of the gene encoding the NlP21 protein of the brown planthopper; the nucleotide sequence of the dsRNA is shown in SEQ ID NO. 3.

[0012] Furthermore, the inhibition of brown planthopper growth is achieved by inhibiting the expression of the gene encoding the NlP21 protein in brown planthoppers.

[0013] Thirdly, the present invention provides a dsRNA for inhibiting the expression of the gene encoding the NlP21 protein of the brown planthopper, wherein the gene encoding the NlP21 protein comprises the nucleotide sequence shown in SEQ ID NO. 2; or, comprises a nucleotide sequence that expresses the same protein as the nucleotide sequence shown in SEQ ID NO. 2 by substitution, deletion and / or addition of one or more nucleotides.

[0014] The dsRNA comprises a nucleotide sequence as shown in SEQ ID NO. 3.

[0015] Fourthly, the present invention provides a method for improving the resistance of rice to brown planthopper, comprising: overexpressing a gene encoding the brown planthopper NlP21 protein in the rice; the gene encoding the NlP21 protein comprising the nucleotide sequence shown in SEQ ID NO. 2; or, comprising a nucleotide sequence comprising one or more nucleotides substituted, deleted, and / or added to the nucleotide sequence shown in SEQ ID NO. 2, and expressing the same protein as the nucleotide sequence shown in SEQ ID NO. 2.

[0016] Fifthly, the present invention provides a method for preparing transgenic rice with resistance to brown planthoppers, wherein the method for improving the resistance of rice to brown planthoppers is used to cultivate transgenic rice with resistance to brown planthoppers.

[0017] In a sixth aspect, the present invention provides a method for inhibiting the growth of brown planthoppers, comprising: inhibiting the expression of the gene encoding the NlP21 protein of brown planthoppers; wherein the gene encoding the NlP21 protein comprises the nucleotide sequence shown in SEQ ID NO. 2; or, comprises a nucleotide sequence that expresses the same protein as the nucleotide sequence shown in SEQ ID NO. 2 by substitution, deletion and / or addition of one or more nucleotides.

[0018] Furthermore, the method for inhibiting the growth of brown planthoppers is to inhibit the expression of the gene encoding the NlP21 protein of brown planthoppers by means of dsRNA; the dsRNA includes the nucleotide sequence shown in SEQ ID NO.3.

[0019] In a seventh aspect, the present invention provides a biological material, which is an expression cassette, a vector, or a transgenic cell; the biological material includes the encoding gene of the brown planthopper NlP21 protein, or includes the dsRNA.

[0020] Compared with the prior art, the advantages of the present invention are:

[0021] 1. This invention discloses the nucleotide sequence of the NlP21 gene of brown planthopper for the first time. Currently, there are no reports on the function of inhibiting its expression to significantly affect the growth and development of brown planthopper.

[0022] 2. Based on the cDNA sequence of the NlP21 gene of the brown planthopper, this invention uses RNAi technology of microinjection of dsRNA to silence the NlP21 gene of the brown planthopper, resulting in a lethal effect in the brown planthopper. As time goes on, the survival rate becomes lower and lower. Obviously, the dsRNA of this gene and its corresponding expression cassette, recombinant vector or recombinant bacteria have important application value in the field of brown planthopper control.

[0023] 3. This invention constructs an overexpression genetic transformation vector targeting the NlP21 gene of the brown planthopper. Experiments have shown that when this vector is transferred into rice plants, the host of the brown planthopper, the resistance of rice to the brown planthopper is greatly improved. After the brown planthoppers feed on the transgenic material, their weight gain and survival rate decrease, indicating that this vector plays an important role in improving the resistance of the brown planthopper. This invention is of great significance for cultivating insect-resistant plants, has excellent application prospects, and has significant application value for reducing pesticide use, maintaining ecological balance, and promoting sustainable development. Attached Figure Description

[0024] Figure 1 The image shows the cloning results of the NlP21 gene provided in Example 1 of this invention; wherein, the first lane is the marker, the second lane is the NlP21 ORF, and the third lane represents the NlP21 ORF sequence after removing the signal peptide;

[0025] Figure 2 This is an agarose gel electrophoresis image of dsNlP21 and dsGFP provided in Example 2 of the present invention;

[0026] Figure 3 The results of the relative expression of the NlP21 gene after microinjection provided in Example 3 of the present invention are shown; where CK is uninjected brown planthopper, dsGFP is brown planthopper injected with dsGFP, and 1-5 are brown planthoppers injected with NlP21 for different days; different lowercase letters (a, b, c) indicate that P < 0.05, reaching a significant difference;

[0027] Figure 4 The results of the microinjection analysis of brown planthopper survival rate and weight gain provided in Example 4 of this invention; wherein, Figure 4 A represents the results of daily survival rate statistics of brown planthoppers after microinjection onto rice plants. Figure 4 B represents the brown planthopper after injection. After the planthopper emerges into an adult, the weight gain of the female planthoppers over two days is measured.

[0028] Figure 5 The brown planthopper feeding controls provided in Example 6 of this invention are Nipponbare and Nipponbare. NlP21 Results of plant phenotypic analysis; among which, Figure 5 A represents wild-type Nipponbare and Nipponbare. NlP21 Results of NlP21 expression analysis in plants; Figure 5 B represents the seedling stage identification results of the NlP21 overexpressing transgenic T2 generation positive strain against brown planthopper; Figure 5 C represents the genetically modified parent plants, Nipponbare and Nipponbare, which are fed on by brown planthoppers. NlP21 Analysis of insect weight gain in transgenic plants two days later; Figure 5 D represents the genetically modified parent plants, Nipponbare and Nipponbare, that were fed on by brown planthoppers.NlP21 Results of brown planthopper survival rate analysis within ten days after transgenic plants. Detailed Implementation

[0029] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] In a first aspect, the present invention provides the application of the brown planthopper NlP21 protein or its encoding gene or a repressor of the encoding gene of the brown planthopper NlP21 protein in regulating plant resistance to brown planthopper, wherein the amino acid sequence of the NlP21 protein is (a) or (b):

[0031] (a) The amino acid sequence shown in SEQ ID NO. 1;

[0032] (b) An amino acid sequence of SEQ ID NO. 1 that has been substituted, deleted and / or added with one or more amino acids, and that has the same function as a protein composed of the amino acid sequence of SEQ ID NO. 1;

[0033] The gene encoding the NlP21 protein includes the nucleotide sequence shown in SEQ ID NO. 2; or, it includes a nucleotide sequence that expresses the same protein as the nucleotide sequence shown in SEQ ID NO. 2 by substitution, deletion and / or addition of one or more nucleotides.

[0034] Secondly, the present invention provides the application of a repressor of the gene encoding the NlP21 protein of the brown planthopper in inhibiting the growth of the brown planthopper, wherein the repressor of the gene encoding the NlP21 protein of the brown planthopper is a dsRNA capable of inhibiting the expression of the gene encoding the NlP21 protein of the brown planthopper; the nucleotide sequence of the dsRNA is shown in SEQ ID NO. 3.

[0035] Example 1

[0036] Cloning of the NlP21 gene in brown planthopper

[0037] Twenty brown planthoppers of biotype 1 were collected, and total RNA was extracted and reversed to cDNA. Primers were designed based on this sequence, and the 5' and 3' end sequences of the candidate gene were obtained using the TaKaRa 5' and 3' RACE kit. The transcription start and termination sites of the candidate gene were determined, and the full-length cDNA sequence of the gene was assembled. Primers NlP21-F and NlP21-R were resynthesized based on the full-length cDNA sequence, and the full-length cDNA of NlP21 was amplified. The ORF was predicted, and its ORF sequence is shown in SEQ ID NO. 1 of the sequence listing. Figure 1 ).

[0038] NlP21-F:5'-ATGGTTACTCAGATCAGTTG-3'; as shown in SEQ ID NO. 4;

[0039] NlP21-R:5'-TTAGGGACACATAACAACGT -3'; as shown in SEQ ID NO. 5.

[0040] Example 2

[0041] Preparation of dsRNA (dsNlP21) for silencing the NlP21 gene in brown planthoppers and dsGFP gene for control.

[0042] 1. Using the cDNA obtained in Example 1 as a template, PCR amplification was performed using dsNlP21-F and dsNlP21-R as primers to obtain the PCR amplification product.

[0043] dsNlP21-F (forward primer): 5'-TAATACGACTCACTATAGGGAGATTCTGGGCCCGCACCGGTTGC-3'; as shown in SEQ ID NO. 6;

[0044] dsNlP21-R (reverse primer): 5'-TAATACGACTCACTATAGGGAGAGTCCTTGGCGTAGCTGTAGGC-3'; as shown in SEQ ID NO. 7;

[0045] The underlined area is the T7 RNA polymerase promoter sequence.

[0046] 2. Using a GFP-containing plasmid as a template, PCR amplification was performed using dsGFP-F and dsGFP-R primers to obtain the PCR amplification product.

[0047] dsGFP-F (forward primer): 5'-TAATACGACTCACTATAGGGCGGACT-3'; as shown in SEQ ID NO. 8;

[0048] dsGFP-R (reverse primer): 5'-TAATACGACTCACTATAGGGCGATGC-3'; as shown in SEQ ID NO. 9;

[0049] The underlined area is the T7 RNA polymerase promoter sequence.

[0050] 3. Recover the amplification product, add A, and ligate it into the pMD18-T (TAKARA) vector. Send the positive clone for sequencing. Once the correct clone is obtained, use this clone plasmid as a template to amplify it again using the primers described above. Purify and concentrate the amplification product to a concentration of 1 μg / μL. This product serves as the template for dsRNA synthesis.

[0051] 4. Add the following reagents to a 200 μL centrifuge tube according to the specified ratio. The system is as follows:

[0052]

[0053] Gently tap to mix, then briefly centrifuge. Place in a PCR apparatus and program: 37 ℃, 4 h; 75 ℃, 5 min; store at 16 ℃. Aspirate 1 μL and perform gel electrophoresis. Once the target band is detected, proceed to the next step.

[0054] 5. Add the following reagents to the centrifuge tubes above to remove DNA and ssRNA:

[0055]

[0056] Mix thoroughly, centrifuge briefly, and place in a PCR instrument at 37 °C for 30 min. Then remove and add 1 μL of EDTA (Fementas), return to the PCR instrument, and incubate at 65 °C for 5 min to terminate the reaction. Pipette 1 μL, dilute 10-fold, and use 2 μL for gel electrophoresis and 2 μL for concentration determination using a Nanodrop UV spectrophotometer. If the detection band is a single, bright band, such as... Figure 2 As shown, if the OD260 / 280 ratio is between 1.8 and 2.0, it indicates that the dsRNA quality is good and the next step can be carried out: RNA phenol-chloroform extraction.

[0057] 6. Perform routine phenol-chloroform extraction to remove proteins. Adjust the concentration of dsRNA to 5 μg / μL, aliquot into 10 μL tubes, and store at -80 ℃.

[0058] Example 3

[0059] Microinjection of dsNlP21 and dsGFP and its efficacy assay

[0060] 1. Brown planthopper preparation: Take 30 females and 10 males and place them in a cup containing TN1 seedlings. After 24 hours, remove the adults. Let them hatch; after 20 days, they will become fourth instar nymphs, which can then be injected.

[0061] 2. Plate preparation: Weigh 1.5 g of agar powder and add it to 100 mL of water, boil, pour into a glass petri dish, and let it solidify for later use.

[0062] 3. Injection: Place 5-8 similarly sized worms in a test tube and anesthetize them with CO2 for 20 seconds. Then, pour the worms onto a 1.5% agar plate, abdomen facing upwards. Inject using a Nanoliter 2010 microinjector according to the instructions. The injection site is between the anterior and mesothorax. The injection volume is 46 nL (5 μg / μL).

[0063] 4. After injecting brown planthoppers with dsRNA, samples were taken starting from the first day after injection, with three samples taken each day for five days. Brown planthoppers that were not injected and those injected with dsGFP were taken as controls. The changes in gene expression levels were verified by qRT-PCR.

[0064] The specific procedures are as follows: After sampling, RNA was extracted and reversed using the TAKARA PrimeScript RT reagent Kit with gDNA Eraser (catalog number RR047A) according to the instructions to obtain the reversed product. 5 μL of the obtained cDNA was diluted 10-fold with TE buffer and subjected to real-time quantitative PCR as follows. The PCR reaction was performed on a CFX96 Touch™ Real-Time PCR Detection System (Bio-Rad) instrument, following the reaction system:

[0065]

[0066] Reaction conditions: 95 ℃ pre-denaturation for 2 min, 95 ℃ denaturation for 5-10 s, TM (55-65 ℃) annealing extension for 30 s, repeating the last two steps for 40 cycles, and finally 65 ℃-95 ℃, increasing by 0.5 ℃ per step, performing melting curve analysis for 5 s to determine the specificity of the amplified products. Three technical replicates were performed for each sample, and amplification efficiency was analyzed for each PCR plate. Results were analyzed using Bio-Rad CFXManager. First, melting curves and QC (quality control) were analyzed to remove unqualified data. Gene expression analysis was performed using the software's built-in Gene Study function (1+E). -ΔΔCt Algorithm analysis.

[0067] internal reference gene actin primers:

[0068] Actin-F: 5'-GACAGGATGCAGAAGGAAATCA-3'; as shown in SEQ ID NO. 10;

[0069] Actin-R: 5'-GACTCGTCGTACTCCTGCTTTG-3'; as shown in SEQ ID NO. 11;

[0070] NlP21 quantitative primers:

[0071] NlP21-1F: 5'-ATCCAACCGACCAACAACCA-3'; as shown in SEQ ID NO. 12;

[0072] NlP21-1R: 5'-CAGTACAAGTCTCCGCCGAA-3'; as shown in SEQ ID NO. 13.

[0073] 5. Results attached Figure 3 As shown, compared with uninjected brown planthoppers and the control group injected with dsGFP, the relative expression level of the NlP21 gene in the microinjection group was significantly reduced from the first day of injection, showing a significant difference compared with the control (P<0.05). The results indicate that microinjection of dsNlP21 can induce the RNAi effect of the salivary gland secretion gene NlP21 in brown planthoppers, leading to a significant decrease in gene expression.

[0074] Example 4

[0075] Phenotypic detection of brown planthoppers after microinjection

[0076] Brown planthopper survival experiment: Brown planthoppers were divided into three groups: uninjected, injected with dsGFP, and injected with dsNlP21. After injection, they were allowed to recover and then released back onto rice. Ten planthoppers were tested each time, repeated 5 times. The results are as follows: Figure 4 As shown in A, the survival rate of brown planthoppers injected with dsNlP21 was significantly lower than that of brown planthoppers injected with dsGFP and those not injected from the third day after injection.

[0077] Brown planthopper weight gain experiment: After injection, brown planthoppers were placed back on rice plants and allowed to emerge as adults. On the first day, each emerging planthopper was weighed individually and then placed in a wax bag tied to a rice seedling. Two days later, the surviving planthoppers were removed and weighed again. The difference between the two weights was recorded as the planthopper's weight gain. Ten planthoppers were tested each time, and the experiment was repeated five times. Figure 4 As shown in Figure B, the weight gain of newly emerged brown planthoppers within 48 hours was analyzed, and it was found that the weight gain decreased after injection of dsNlP21. The results indicate that the reduced expression of the dsNlP21 gene after injection affected the feeding of brown planthoppers, thus impacting their survival rate.

[0078] Example 5

[0079] Construction of a genetic transformation vector for overexpressing the NlP21 gene in brown planthopper

[0080] 1. ORF sequence amplification (removal of the signal peptide region): using the high-fidelity enzyme KOD Plus Neo (TOYOBO) and primer NLP21. -SP -F and NlP21 -SP -R, the template is a plasmid containing the NlP21 gene, amplifying the ORF sequence of the NlP21 gene.

[0081] NlP21 -SP -F: 5'-ATGGTGAAACTCTCGATAGT-3'; as shown in SEQ ID NO. 14;

[0082] NlP21 -SP -R: 5'-GGGACACATAACAACGTCGT-3'; as shown in SEQ ID NO. 15.

[0083] 2. After PCR, take 2 μL for agarose gel electrophoresis. If the band is single, recover it directly; if there are extraneous bands, cut the gel and recover the fragment of the target size, approximately 0.7 kb. Since the KOD PLUS NEU amplification fragment does not have an A tail at the end, an A tail needs to be added before ligation into the vector.

[0084] 3. The pCXUN vector was digested and recovered using Xcm I enzyme to form a T-terminus, which was then ligated to the A-added product at 16 °C overnight. Transformation was performed, and single clones were selected. The vector primers were UBIS and UBIA. PCR was used to verify the insert size; fragments approximately 1 kb in size were sent to the sequencing company.

[0085] UBIS: 5'-TGTTTCTTTTGTCGATGCTCACCC-3'; as shown in SEQ ID NO. 16;

[0086] UBIA: 5'-TTCTATCGCGGCTTAACGTAATTCA-3'; as shown in SEQ ID NO. 17.

[0087] 4. Transform the correctly sequenced vector plasmid into Agrobacterium strain EHA105 using conventional electroporation.

[0088] Example 6

[0089] Functional verification of transgenes after NlP21 overexpression

[0090] 1. Obtaining NlP21 overexpression transgenic plants mediated by Agrobacterium

[0091] Genetic transformation mediated by Agrobacterium EHA105 was employed (Hiei et al., 1994, Efficient transformation of rice). Oryza sativa L.) mediated by Agrobacterium (and sequence analysis of the boundaries of the T-DNA. Plant Journal 6:271-282) The above NlP21 overexpression genetic transformation vector was introduced into Nipponbare.

[0092] 2. Brown planthoppers feeding on Japanese scorching sun NlP21 Phenotypic verification of transgenic plants

[0093] After harvesting the seeds, the T2 generation homozygous transgenic plants of Nipponbare were subjected to... NlP21 , Nipponbare NlP21 Quantitative PCR was used to detect the expression of the NlP21 gene. Primers were NlP21-1F and NlP21-1R, and the internal control was Osactin, with primers Osactin-F and Osactin-R. The results are as follows: Figure 5 As shown in A, the NlP21 gene accumulates in large quantities in transgenic plants.

[0094] NlP21-1F: 5'-ATCCAACCGACCAACAACCA-3'; as shown in SEQ ID NO. 18;

[0095] NlP21-1R: 5'-CAGTACAAGTCTCCGCCGAA-3'; as shown in SEQ ID NO. 19;

[0096] Osactin-F: 5'-GATCACTGCCTTGGCTCCTA-3'; as shown in SEQ ID NO. 20;

[0097] Osactin-R: 5'-GTACTCAGCCTTGGCAATCC-3'; as shown in SEQ ID NO. 21;

[0098] The resistance of positive transgenic lines to brown planthopper was identified using the seedling group method. Ten days after inoculation with brown planthoppers, the control variety Nipponbare died completely, while the transgenic positive lines overexpressing the NlP21 gene still survived, indicating that the NlP21 gene has the function of enhancing rice resistance to brown planthoppers. Figure 5 (B in the text). Therefore, the brown planthopper gene NlP21 can be applied in rice to breed rice varieties with resistance to brown planthoppers.

[0099] Twenty second-instar brown planthoppers of biotype I fed on Nipponbare and Nipponbare. NlP21 The survival rate of the insects was determined by the number of days, and the experiment was repeated five times. The results are as follows: Figure 5 As shown in C, due to the transgenic plant Nipponbare... NlP21 Increased resistance affected the feeding of brown planthoppers, significantly reducing their survival rate on day 10.

[0100] Newly emerged female brown planthoppers of biotype I were reared in Nipponbare. NlP21 and Nippon Haru NlP21 Two days later, weigh the worms, 10 worms each time. Repeat three times. Results are as follows. Figure 5 As shown in D, the weight of brown planthoppers was also significantly reduced. All of the above results indicate that the NlP21 gene can improve the resistance of rice to brown planthoppers.

[0101] The above detailed embodiments describe the implementation of the present invention; however, the present invention is not limited to the specific details described in the above embodiments. Within the scope of the claims and technical concept of the present invention, various simple modifications and changes can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. The application of the brown planthopper NlP21 protein or its encoding gene in improving rice resistance to brown planthopper, characterized in that, The amino acid sequence of the NlP21 protein is the amino acid sequence shown in SEQ ID NO. 1; The gene encoding the NlP21 protein has the nucleotide sequence shown in SEQ ID NO.

2.

2. The application of the brown planthopper NlP21 protein or its encoding gene according to claim 1 in improving rice resistance to brown planthopper, characterized in that, The method of improving the resistance of rice to brown planthopper is to overexpress the gene encoding the NlP21 protein of brown planthopper in the rice.

3. The application of a repressor of the gene encoding the NlP21 protein of the brown planthopper in inhibiting the growth of the brown planthopper, characterized in that, The repressor of the gene encoding the brown planthopper NlP21 protein is a dsRNA that can inhibit the expression of the gene encoding the brown planthopper NlP21 protein; the nucleotide sequence of the dsRNA is shown in SEQ ID NO.

3.

4. A method for improving the resistance of rice to brown planthopper, characterized in that, include: The gene encoding the NlP21 protein of the brown planthopper was overexpressed in the rice. The gene encoding the NlP21 protein has the nucleotide sequence shown in SEQ ID NO.

2.

5. A method for preparing transgenic rice resistant to brown planthoppers, characterized in that, Using the method described in claim 4 for improving the resistance of rice to brown planthoppers, transgenic rice with resistance to brown planthoppers was bred.

6. A method for inhibiting the growth of brown planthoppers, characterized in that, include: Inhibit the expression of the gene encoding the NlP21 protein in brown planthopper; The gene encoding the NlP21 protein has the nucleotide sequence shown in SEQ ID NO.

2.

7. The method for inhibiting the growth of brown planthoppers according to claim 6, characterized in that, The expression of the gene encoding the brown planthopper PIB14 protein in brown planthopper was inhibited by dsRNA; the nucleotide sequence of the dsRNA is shown in SEQ ID NO. 3.

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