Application of small brown planthopper saliva gene LsSP and its dsRNA in prevention and treatment of spread of rice stripe virus RSV

Abstract

The application discloses an application of a Laodelphax striatellus saliva gene LsSP and dsRNA thereof in preventing and treating the spread of rice stripe virus RSV by the Laodelphax striatellus, and belongs to the field of biological control of pests.The dsRNA targeting the saliva gene LsSP of the Laodelphax striatellus is synthesized by an in vitro transcription method, and is introduced into the Laodelphax striatellus, so that the expression of the saliva gene LsSP of the Laodelphax striatellus can be effectively interfered, the ability of the Laodelphax striatellus to spread the rice stripe virus RSV can be reduced, and the virus can be prevented from damaging the rice production.The application is specifically directed to the link of the Laodelphax striatellus to spread the rice stripe virus RSV, is harmless to mammals, fish and shrimps, natural enemy insects and pollinating insects, has the advantages of quick effect, environmental friendliness and the like, and has a good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of genetic engineering technology, specifically relating to the application of the planthopper saliva gene LsSP and its dsRNA in preventing the spread of rice stripe virus (RSV) by planthoppers. Background Technology

[0002] Rice stripe virus (RSV), causing rice stripe leaf blight, is a significant disease in rice production, seriously threatening my country's food security. Under natural conditions, this virus cannot spread through soil or the sap of infected plants, but only through insect vectors, primarily planthoppers. Currently, control of rice stripe leaf blight mainly relies on chemical control of planthoppers. However, the widespread use of traditional pesticides not only causes serious environmental problems but also leads to pesticide resistance in planthoppers, hindering sustainable agricultural development. Therefore, developing a novel rice stripe leaf blight control technology is a good way to address the current overuse of chemical pesticides.

[0003] RNA interference (RNAi) technology has become a hot topic in life science research in recent years. It specifically degrades or inhibits the expression of target gene mRNA through small double-stranded RNA, thereby suppressing or shutting down specific genes. RNAi technology has advantages such as high specificity, high efficiency, and ease of operation. Currently, this technology is widely used in the control of various agricultural pests, that is, by introducing specific dsRNA into insects, it aims to control pest populations or reduce the ability of pests to transmit viruses.

[0004] Rice stripe virus (RSV) spreads cyclically within the planthopper (Gnaphalium affine), persistently transmitting the virus once infected. Infected females can also transmit the virus to the next generation via eggs, posing a significant challenge to virus control. Current research on blocking RSV transmission by planthoppers mainly focuses on inhibiting the virus's ability to cross the midgut barrier. However, due to RSV's transocular transmission characteristic, the virus can achieve vertical intergenerational transmission without passing through the midgut. Therefore, inhibiting RSV's ability to cross the salivary gland barrier and preventing its release into plant tissues is crucial for control. Summary of the Invention

[0005] In view of this, the purpose of this invention is to reduce the efficiency of rice stripe virus (RSV) transmission by the planthopper by targeting the key salivary gene (Laodelphax striatellus salivary protein, LsSP), thereby mitigating the damage of RSV to rice and providing a sequence and data basis for the prevention and control of rice viruses.

[0006] To achieve the above objectives, this invention cloned the protein sequence encoding the LsSP gene in the saliva of the planthopper, obtained the dsRNA of the LsSP gene through in vitro synthesis, and introduced it into the planthopper. Silencing the LsSP gene does not affect the survival rate of the planthopper, but significantly reduces the efficiency of the planthopper in transmitting RSV. Even if some planthoppers can still transmit the virus, the amount of virus carried by the infected rice is significantly reduced and the symptoms are weakened, ultimately achieving the goal of controlling rice stripe virus disease.

[0007] The present invention mainly adopts the following technical solutions:

[0008] The first aspect of this invention provides the application of the planthopper saliva gene LsSP as a target gene in the prevention and control of planthopper transmission of rice stripe virus (RSV).

[0009] The second aspect of the present invention provides a dsRNA targeting the saliva gene LsSP of the planthopper, wherein the dsRNA is synthesized by in vitro transcription after amplification using primers SEQ ID NO.6 and SEQ ID NO.7 and a nucleotide sequence shown in SEQ ID NO.1 or having at least 90% homology with SEQ ID NO.1 and encoding amino acids as shown in SEQ ID NO.2 as a template.

[0010] Preferably, the dsRNA consists of the nucleotide sequence shown in SEQ ID NO.14 and a nucleotide sequence that is inversely complementary to the nucleotide sequence shown in SEQ ID NO.14.

[0011] A third aspect of the present invention provides the application of the above-mentioned dsRNA in interfering with the expression of the LsSP gene in the saliva of the planthopper.

[0012] The fourth aspect of this invention provides the application of the above-mentioned dsRNA in controlling the spread of rice stripe virus (RSV) by planthoppers.

[0013] Preferably, the prevention and control of rice stripe virus (RSV) transmission by planthoppers includes reducing the susceptibility and / or viral load of healthy rice that has been fed on by planthoppers to RSV.

[0014] The fifth aspect of the present invention provides a biological agent for controlling the spread of rice stripe virus (RSV) by planthoppers, wherein the active ingredient of the biological agent comprises the aforementioned dsRNA.

[0015] The sixth aspect of the present invention provides a method for preventing the spread of rice stripe virus (RSV) by planthoppers, wherein a solution containing the above-mentioned dsRNA or the above-mentioned biological drug is introduced into the planthoppers by injection and / or feeding.

[0016] The beneficial effects of this invention are as follows:

[0017] (1) This invention discloses the LsSP saliva gene of the planthopper. By introducing the dsRNA of the obtained LsSP gene into the planthopper and silencing the LsSP gene, the ability of the planthopper to transmit rice stripe virus (RSV) can be significantly reduced, and the susceptibility and viral load of rice can be reduced. This indicates that the LsSP saliva gene of the planthopper plays a key role in the transmission of the virus by the planthopper and has important value in the biological control of planthopper and rice stripe virus (RSV).

[0018] (2) This invention specifically targets the rice stripe virus (RSV) transmission link of planthoppers, and is harmless to mammals, fish and shrimp, natural enemy insects and pollinating insects. It has the advantages of being fast-acting and environmentally friendly, and has good application prospects. Attached Figure Description

[0019] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the following figures are provided for illustration:

[0020] Figure 1 This is a diagram showing the PCR amplification results of the LsSP gene in the saliva of the planthopper in Example 1 of this invention;

[0021] Figure 2 This is a diagram showing the experimental results of dsRNA synthesis of the LsSP gene in the saliva of the planthopper in Example 2 of the present invention;

[0022] Figure 3 This is a graph showing the change in the expression level of the target gene after the dsRNA of the LsSP saliva gene of the planthopper was introduced into the planthopper in Example 4 of the present invention (dsGFP represents the dsRNA introduction group of the GFP gene, and dsLsSP represents the dsRNA introduction group of the LsSP gene).

[0023] Figure 4 This is a graph showing the efficiency of rice stripe virus (RSV) transmission by planthoppers after the dsRNA of the LsSP saliva gene of planthopper was introduced into planthoppers in Example 5 of the present invention (dsGFP represents the dsRNA introduction group of the GFP gene, and dsLsSP represents the dsRNA introduction group of the LsSP gene).

[0024] Figure 5 This is a comparison chart of viral load and symptoms of rice after infection with rice stripe virus (RSV) in Example 5 of the present invention (A: Rice leaves not infected with RSV; B: Rice leaves infected with RSV by planthoppers injected with GFP gene dsRNA; C: Rice leaves infected with RSV by planthoppers injected with LsSP gene dsRNA). Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0026] Example 1: Cloning of the LsSP gene in the saliva of the planthopper

[0027] 1. Amplification of the LsSP gene fragment in the planthopper

[0028] (1) Take the nymphs of the planthopper and anesthetize them on ice; add pre-cooled 1×PBS (37mM NaCl, 2.68mM KCl, 8.1mM Na2HPO4, 1.47mM KH2PO4, pH 7.4) to a glass slide and immediately dissect the salivary glands of the planthopper under a stereomicroscope.

[0029] (2) The dissected salivary glands were added to 1 ml of Trizol (Takara) and ground thoroughly; 400 μl of chloroform was added and mixed vigorously, then centrifuged at 12,000 rpm at 4°C for 15 minutes. The top aqueous phase was carefully aspirated and transferred to a new centrifuge tube; an equal volume of isopropanol was added, mixed, and allowed to stand at room temperature; after 10 minutes, the mixture was centrifuged at 12,000 rpm for 10 minutes, the supernatant was discarded, and 1 ml of 75% ethanol was added to the precipitate; after centrifugation at 9600 rpm for 5 minutes, the supernatant was discarded, and an appropriate amount of RNase-free water was added to the precipitate; the RNA concentration was determined using NanoDrop.

[0030] (3) The total RNA extracted from the salivary glands of the planthopper was reverse transcribed using the ReverTra Ace qPCR RT Master with gDNAremover kit: First, the total RNA was denatured at 65°C for 5 min; 1 μg of total RNA was added to 2 μl of 4×DNMaster Mix and brought to 8 μl with RNase-free water; after mixing, it was incubated at 37°C for 5 min to remove contaminating genomic DNA; then, 2 μl of 5×RT Master Mix was added to the system; after mixing, it was incubated at 37°C for 1 h; finally, it was denatured at 98°C for 5 min to inactivate the reverse transcriptase and finally obtain the cDNA from the salivary glands of the planthopper.

[0031] (4) Primers were designed based on the full-length LsSP gene sequence as shown in Table 1. The primers were synthesized by Hangzhou Youkang Biotechnology Co., Ltd.

[0032] Table 1 Primers for LsSP gene amplification

[0033]

[0034] (5) Using cDNA from the salivary glands of the planthopper as a template, the target gene was amplified by PCR using the primers shown in Table 1. The specific amplification system was as follows: Max Buffer 25μl, dNTP Mix (10mM each) 1μl, 1 μl of MaxSuper-Fidelity DNA Polymerase, 1 μl each of upstream and downstream primers, 1 μl of cDNA template from the salivary glands of the planthopper, and finally, bring the total volume to 50 μl with ddH2O. PCR amplification conditions were: 95℃ for 3 minutes; 95℃ for 15 seconds, 60℃ for 1 minute, 35 cycles; 72℃ for 10 minutes.

[0035] 2. Obtaining a single clone strain of the LsSP gene from the planthopper.

[0036] (1) Separate PCR products using 1% agarose gel electrophoresis. Figure 1 ), and cut the desired segment with a blade;

[0037] (2) DNA fragments containing the target fragment were recovered using a DNA agarose gel extraction kit (Shanghai Sangon Biotech, SK8131): The agarose gel containing the target fragment was cut from the agarose gel and placed into a centrifuge tube; 5 volumes of gel dissolving buffer B2 were added, and the mixture was incubated at 70°C for 10 minutes; the dissolved gel solution was added to the adsorption column, centrifuged at 8,000g for 30 seconds, and the waste liquid was discarded; 500 μl of wash solution was added, centrifuged at 9,000g for 30 seconds, and the waste liquid was discarded; the empty adsorption column was centrifuged at 9,000g for 1 minute; the adsorption column was placed into a new centrifuge tube, and 30 μl of ddH2O was added to the center of the adsorption column; the column was centrifuged at 10,000g for 2 minutes, and the purified LsSP gene DNA fragment of the planthopper was finally obtained.

[0038] (3) The DNA fragment of the LsSP gene of the planthopper was ligated into the pClone007 vector using the blunt-end cloning kit (Beijing Qingke Biotechnology Co., Ltd.): 1 μl of the LsSP gene DNA fragment of the planthopper, 1 μl of pClone007 Blunt simple vector, and 1 μl of 10× buffer were added sequentially to a 0.2 ml centrifuge tube. Finally, ddH2O was added to bring the total volume to 10 μl. The sample was mixed and reacted at 25 °C for 5 minutes.

[0039] (4) Add the ligation product to competent cells, gently tap the tube wall with your hand, and incubate on ice for 30 minutes; transfer the centrifuge tube to a 42°C water bath for 90 seconds, and quickly remove it and let it stand on ice for 2 minutes; add 500 μl of antibiotic-free LB medium to the centrifuge tube and shake at 180 rpm for 1 hour; take 100-200 μl of bacterial suspension and spread it on LB plates containing ampicillin resistance.

[0040] (5) Pick a single colony and add it to 1 ml of LB liquid medium containing ampicillin resistance. Shake at 180 rpm for 6 hours. Perform colony PCR on the bacterial culture. The reaction system is as follows: Max Buffer 12.5μl, dNTP Mix (10mM each) 0.5μl, Max Super-Fidelity DNA Polymerase 0.5 μl, forward and reverse primers (as shown in Table 1) 0.5 μl each, bacterial culture 1 μl, and finally ddH2O to bring the total volume to 25 μl. PCR amplification conditions were: 95℃ for 3 minutes; 95℃ for 15 seconds, 60℃ for 1 minute, 35 cycles; 72℃ for 10 minutes.

[0041] (6) The PCR products were separated by 1% agarose gel electrophoresis, recombinant clones were selected and sent to Hangzhou Youkang Biotechnology Co., Ltd. for sequencing. The 771bp LsSP gene sequence of the planthopper was obtained. The obtained sequence is shown in SEQ ID NO.1, and the encoded amino acid sequence is shown in SEQ ID NO.2.

[0042] ATGAAGGGTTTGGTATTGTGTGCGGTTTTCCTAGTTTTGGGCGGAAATCAATCATTCGGTGTTAATGTCAACTTGGACTTCTTAAAAGATCCTGATTTCCCAGGAAACGCAGGTTGGAATGCAAAATTGAACCAGCAAATCGCAGATACGGTAAATAATCCTGATTTCCCAGGAAATGCAGGTTGGAATGCAAAATTGGACCAGCAAATCAAAGATACGATGAATTCAGCTATGAACTCAGCTAATACGGGCAGCAGTGGATCAAATGTTGTGTCAAATAGCATGCAGAACATGGAGAACATAAATGTTGGAAATGATTATGTGACCAGTACTGCACCAACTTTGAATAGGCCTACACCTGTACCTGCCGTGCCAATGAAACCGAGTTTCAATATTCAAGGACCAAATCTGCAAAACATGAGGCTCCCACATGCCCCTCCAAACTTCCCCTTCCCCCCTGATTGTTCAGAGGTTGCAGATCCCGGCTACAAATTCCGTGATCCCTTGCAAATCAATTACGGAGATCAGAAACCAGAGATTCGACACCGTTCTTTCCTGTGCACTGATCCTGAATATGGTCAGGACAGTTTCTACATGCAGATGACAGAGGCTCGTAATCCCAATGGTTCTGGTAGTAGCCGAATAGCTGCCTATTACGACAAGACTGGCAATAGTATCGATTATTCTAGAAAGATGATATTCTTACCTCTAGGAGAGAAACTACCAGATATGCCGAGAAATGACTATTTGAAAATGGACGTTACGTTTTAA(SEQ ID NO.1)

[0043] MKGLVLCAVFLVLGGNQSFGVNVNLDFLKDPDFPGNAGWNAKLNQQIADTVNNPDFPGNAGWNAKLDQQIKDTMNSAMNSANTGSSGSNVVSNSMQNMENINVGNDYVTSTAPTLNRPTPVPAVPPMKPSF NIQGPNLQNMRLPHAPPNFPFPPDCSEVADPGYKFRDPLQINYGDQKPEIRHRSFLCTDPEYGQDSFYMQMTEARNPNGSGSSRIAAYYDKTGNSIDYSRKMIFLPLGEKLPDMPRNDYLKMDVTF(SEQ ID NO.2)

[0044] Example 2: dsRNA synthesis of the LsSP gene in the planthopper

[0045] 1. T7 primer PCR amplification and purification

[0046] (1) Using recombinant plasmids or bacterial cultures containing the LsSP gene of the planthopper as templates, the target gene was amplified using primers containing the T7 promoter sequence (shown in Table 2). The primers were synthesized by Hangzhou Youkang Biotechnology Co., Ltd., and the amplification system was as follows: Max Buffer 100μl, dNTP Mix (10mM each) 4μl, 4 μl of Max Super-Fidelity DNA Polymerase, 4 μl each of forward and reverse primers (SEQ ID NO.6 and SEQ ID NO.7), 4 μl of recombinant plasmid or bacterial culture, and finally, bring the total volume to 200 μl with ddH2O. PCR amplification conditions were: 95℃ for 3 minutes; 95℃ for 15 seconds, 60℃ for 1 minute, 35 cycles; 72℃ for 10 minutes.

[0047] Table 2 Primers with T7 promoter sequences

[0048]

[0049] (2) The amplification products were separated by agarose gel electrophoresis and recovered by a DNA agarose gel recovery kit to obtain a large number of single LsSP gene fragments containing the T7 promoter. The obtained sequence is shown in SEQ ID NO.5.

[0050] (SEQ IDNO.5)

[0051] 2. Synthesis and purification of dsRNA

[0052] The dsRNA of the LsSP gene was synthesized and purified using the T7 High Yield RNA transcription kit from Novizan Biotechnology Co., Ltd., as follows:

[0053] (1) Using the LsSP gene fragment obtained by PCR amplification as a DNA template, dsRNA was synthesized. The reaction system was: 2 μl 10×Reaction Buffer, 2 μl ATP solution, 2 μl UTP solution, 2 μl CTP solution, 2 μl GTP solution, 2 μl enzyme mix, 1 μg DNA template, and RNase-free water was added to make up to 20 μl. After the reaction system was prepared, it was mixed and reacted at 37°C overnight.

[0054] (2) Add 1 μl of TURBO DNase to the reaction system to eliminate DNA in the reaction system, and react at 37°C for 15 min;

[0055] (3) Denature the reacted sample at 65℃ for 5 min;

[0056] (4) The concentration of dsRNA was determined using Nanodrop, and the mass of dsRNA was determined by 1% agarose gel electrophoresis. Figure 2 );

[0057] (5) Store the dsRNA of the LsSP gene at 80℃ for later use; one of the nucleotide sequences of the dsRNA of the LsSP gene is shown in SEQ ID NO.14.

[0058] (SEQ ID NO.14)

[0059] Example 3: Introduction of dsRNA of LsSP gene into gray planthopper

[0060] The dsRNA of the LsSP gene was introduced into the planthopper using microinjection. The specific method is as follows:

[0061] (1) Select 3rd instar nymphs from a population of rice stripe virus RSV-carrying planthoppers and anesthetize them with CO2 for 10 seconds.

[0062] (2) Use a capillary puller (P 97, Sutter Instrument) to pull the glass capillary (Wuhan Micro-Exploration Scientific Instrument Co., Ltd.) to the appropriate size. The program parameters are set as follows: heat = 800, pull = 150, vel = 150, time = 80.

[0063] (3) The dsRNA of the GFP and LsSP genes was injected into the glass capillary using a micro-pipette (Eppendorf).

[0064] (4) Install the glass capillary tube with the sample added into the microinjector (Eppendorf) and introduce dsRNA into the planthopper under a stereomicroscope. The microinjector parameters are set as follows: injection pressure 800 Pah, injection time 0.3s, compensation pressure 10 Pah.

[0065] (5) Using the same method, the dsRNA of the Aequorea victoria green fluorescent protein (GFP) gene was introduced into the planthopper as a negative control.

[0066] (6) After the planthoppers that have been introduced with dsRNA have recovered, they are transferred to healthy rice plants and fed for another 6 days.

[0067] Example 4: Detection of dsRNA silencing efficiency of LsSP gene

[0068] Six days after introducing the dsRNA of the LsSP gene into the planthopper, the planthoppers were collected, and the expression level of the LsSP gene was measured. The specific method is as follows:

[0069] (1) The collected planthoppers were ground up, total RNA was extracted using the Trizol method, and cDNA of planthoppers was obtained by reverse transcription using the ReverTra Ace qPCR RTMaster with gDNA remover kit;

[0070] (2) Using Primer 6.0 software, quantitative primers for the LsSP gene (SEQ ID NO.8 and SEQ ID NO.9) and the Lsactin gene (SEQ ID NO.10 and SEQ ID NO.11) of the planthopper were designed, as shown in Table 3. The primers were synthesized by Nanjing Genscript Biotech Co., Ltd.

[0071] Table 3 Primers for quantitative PCR of LsSP and Lsactin genes.

[0072]

[0073] (3) Using cDNA from the planthopper as a template, iTaq was used. TM The expression levels of the LsSP gene and the Lsactin gene in the planthopper were determined using the Universal SYBR Green Supermix (Shanghai Yisheng Biotechnology Co., Ltd.) fluorescence quantitative detection reagent. The reaction system was prepared as follows: 6.8 μl H2O, 10 μl 2×SYBR Green Supermix, 0.6 μl forward primer, 0.6 μl reverse primer, and 2 μl cDNA template. The reaction was then analyzed using Roche Light. The 480 Real-Time PCR System was run with the following program: 95℃ pre-denaturation for 30 s, 95℃ denaturation for 5 s, 60℃ extension for 30 s, for a total of 40 cycles of denaturation and extension; a negative control without RNase water was set up for each primer pair.

[0074] (4)Use 2 -ΔΔCt The expression level of the LsSP gene in the planthopper was calculated using the method described above, and the Student's t-test was used to test the significance of differences between different treatment groups.

[0075] (5) Experimental results are as follows Figure 3 As shown, the LsSP gene expression level in the planthopper with introduced LsSP gene dsRNA was significantly lower than that in the control group, indicating that the LsSP gene dsRNA has a high silencing efficiency for the LsSP gene in the planthopper.

[0076] Example 5: Determination of the virus-transmitting ability of infected planthoppers with introduced dsRNA

[0077] The ability of rice leafhoppers injected with dsRNA and carrying rice stripe virus (RSV) to transmit the virus to rice was determined using the following method:

[0078] (1) Plant healthy rice plants with 1-2 leaves in plastic cups (10cm in diameter and 30cm in height), with one rice plant in each cup;

[0079] (2) Planthoppers injected with dsRNA (6 days) and carrying rice stripe virus RSV were introduced into plastic cups, with 6 planthoppers in each plastic cup;

[0080] (3) Planthoppers injected with dsRNA (6 days) and carrying rice stripe virus RSV were fed on healthy rice for 48 hours, and then the planthoppers were removed.

[0081] (4) Continue to cultivate the rice that has been fed on by the planthoppers for 21 days;

[0082] (5) After 21 days, total RNA was extracted from rice stems using the Trizol method and the first strand of cDNA was synthesized. Then, using cDNA as a template, the rice stripe virus RSV coat protein CP gene was amplified. The primers used, SEQ ID NO.12 and SEQ ID NO.13, are shown in Table 4. The primers were synthesized by Nanjing Genscript Biotech Co., Ltd.

[0083] Table 4 Primers for amplifying the CP gene of rice stripe virus (RSV) coat protein.

[0084]

[0085] (6) Calculate the efficiency of rice stripe virus transmission by planthoppers: v = number of infected rice plants / number of rice plants consumed by planthoppers. The experimental results are as follows: Figure 4 As shown, the proportion of healthy rice plants fed on by infected planthoppers with the LsSP gene dsRNA was significantly lower than that of the control group, indicating that introducing the LsSP gene dsRNA into planthoppers can effectively reduce the efficiency of planthoppers in transmitting rice stripe virus.

[0086] (7) Observe the phenotype of the virus-infected rice, and the results are as follows: Figure 5 As shown, compared with healthy rice leaves that were not infected with RSV ( Figure 5 Compared to A), rice leaf symptoms in planthoppers injected with GFP gene dsRNA and infected with RSV were significantly more pronounced. Figure 5 In the case of B), rice leaf symptoms were not obvious in planthoppers injected with LsSP gene dsRNA that were infected with RSV. Figure 5 The C in the figure indicates that although the planthopper with partial inhibition of the LsSP gene can still transmit the virus to rice, the viral load in the infected rice decreases and the symptoms are weakened.

[0087] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. Application of dsRNA of LsSP gene of Laodelphax striatellus to control the transmission of Rice stripe virus RSV by L. striatellus, characterized in that, The dsRNA consists of a nucleotide sequence as shown in SEQ ID NO. 14 and a nucleotide sequence reverse complementary to the nucleotide sequence as shown in SEQ ID NO.

14.

2. Use according to claim 1, characterized in that, The control of the spread of the rice stripe virus RSV by the planthopper includes reducing the infection rate and / or the virus-carrying amount of the rice stripe virus RSV on healthy rice plants that have been fed on by the planthopper.

3. A biological medicine for preventing and treating the spread of Laodelphax striatellus to rice stripe virus (RSV), characterized by, The active ingredient of the biological medicine comprises the dsRNA as claimed in claim 1.

4. A method for preventing the spread of rice stripe virus (RSV) by the small brown planthopper (SBPH) comprising, wherein The solution containing the dsRNA as claimed in claim 1 or the biological medicine as claimed in claim 3 is introduced into the planthopper by injection and / or feeding.

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