Aphis gossypii Armet protein and coding gene and application thereof

Abstract

The invention relates to the technical field of insect genetic engineering, in particular to an aphid gossypii gossypii Armet protein and a coding gene and application thereof. The nucleotide sequence of the separated cotton aphid Armet gene is as shown in SEQ ID NO: 1, and the sequence of the protein coded by the cotton aphid Armet gene is as shown in SEQ ID NO: 2. The invention further provides application of the cotton aphid Armet gene RNA interference sequence. The sequence has a good silencing effect on the cotton aphid Armet gene. According to the Armet interference sequence-transformed VIGS cotton plant, the number of offspring of the cotton aphid is remarkably reduced, and the population development can be effectively controlled. Furthermore, the gene and the protein disclosed by the invention can be used for developing transgenic insect-resistant plants and biologically preventing and controlling cotton aphids.

Description

Technical Field

[0001] The invention relates to the technical field of insect genetic engineering, in particular to cotton aphid Armet protein and its encoding gene and application. Background Art

[0002] Cotton aphid (Aphis gossypii Glover) belongs to the order Hemiptera, family Aphididae, and is a piercing-sucking insect widely distributed in tropical, subtropical, and temperate regions. It is an insect with a wide ecological range. Cotton aphid has become a global pest that harms cotton, a variety of vegetables, and ornamental plants. It is reported that in the world, cotton aphid hosts as many as 75 families and 285 species. High fecundity, short reproductive cycle, and strong flight muscles enable aphids to adapt to a variety of environments, making prevention and control difficult. Long-term use of chemical pesticides has led to aphids' resistance to many pesticides, reducing the sensitivity of pests to pesticides. Excessive use of pesticides can also lead to a reduction in beneficial insects. The development and use of pollution-free prevention and control measures that conform to the concepts of environmental protection, health, and sustainable development have become the current hotspots of prevention and control.

[0003] RNAi can be triggered by exogenous double-stranded RNA (dsRNA) and induce specific and efficient mRNA degradation. RNAi technology is a commonly used technology to study insect gene function. It also has the potential to be developed as an insect control strategy by targeting genes related to growth and development.

[0004] During feeding, insects that feed on phloem secrete saliva into the plant body. The insect saliva contains salivary proteins that inhibit the plant's defense response. Aphid salivary proteins enter the plant through the piercing-sucking mouthparts. These salivary proteins can act as effectors to inhibit the plant's defense response, such as Ca 2+ Binding protein, by binding to Ca 2+ , preventing the host plant from blocking the reaction, thereby inhibiting the host plant's defense response. In addition, aphid saliva contains detoxification effectors such as polyphenol oxidase, which can oxidize phenolic substances in plants and degrade their toxicity. Therefore, salivary glands are crucial to the biological success of aphids. At present, many salivary proteins have been found in aphids and planthoppers, such as C002, Armet (Arginine rich, mutated in early stage of tumours), Mp55, Me47, MIF, and DNase II.

[0005] If a salivary protein that plays an important role in the adaptability of cotton aphids can be discovered, it will provide new ideas for controlling the development of cotton aphid populations. Summary of the invention

[0006] The invention provides cotton aphid Armet protein and its encoding gene and application.

[0007] The present invention provides an Armet protein, wherein the Armet protein has any of the following amino acid sequences:

[0008] (1) the amino acid sequence shown in SEQ ID NO.2;

[0009] (2) an amino acid sequence having at least 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% identity with the amino acid sequence shown in SEQ ID NO. 2, wherein the protein has the function of affecting the reproduction of cotton aphids;

[0010] (3) An amino acid sequence obtained by replacing and / or deleting and / or adding one or more amino acid residues in the amino acid sequence shown in SEQ ID NO. 2, wherein the protein has the function of affecting the reproduction of cotton aphids.

[0011] Preferably, the protein encoded by the cotton aphid Armet gene of the present invention has a protein sequence as shown in SEQ ID NO: 2, encoding 173 amino acid residues.

[0012] The present invention also provides a gene encoding the Armet protein, wherein the Armet gene contains the nucleotide sequence at positions 38 to 559 shown in SEQ ID NO.1.

[0013] Preferably, the cDNA sequence of the cotton aphid Armet gene of the present invention is shown in SEQ ID NO: 1, and the full length of the cDNA sequence is 522 bp.

[0014] Preferably, the Armet gene contains the nucleotide sequence shown in SEQ ID NO.1.

[0015] The present invention also includes biological materials containing the Armet gene, wherein the biological materials are expression cassettes, vectors, host cells or recombinant bacteria;

[0016] Preferably, the host cell is a host cell that can develop into a plant individual and / or a host cell that cannot develop into a plant individual.

[0017] The present invention also provides a dsRNA for inhibiting the reproduction of cotton aphids, which is a dsRNA of the Armet gene;

[0018] Preferably, the nucleotide sequence of the dsRNA includes the nucleotide sequence amplified by primers SEQ ID NO.5-6.

[0019] The present invention also provides a primer for amplifying the dsRNA;

[0020] Preferably, it includes SEQ ID NO. 5-6.

[0021] The present invention also provides the use of the Armet protein, the gene encoding the Armet protein, the biological material containing the Armet gene, or the dsRNA for inhibiting the reproduction of cotton aphids in any of the following:

[0022] 1) Control insects;

[0023] Preferably, reducing the litter size of cotton aphids;

[0024] 2) Transgenic plant breeding;

[0025] 3) Preparation of pesticides;

[0026] Preferably, the insect is an Aphididae animal, more preferably an Aphididae animal, and even more preferably a cotton aphid;

[0027] Preferably, it is preferably used in transgenic plants resistant to cotton aphid.

[0028] According to the application, it is used to inhibit the reproduction of cotton aphids and reduce the population of cotton aphids.

[0029] According to the application, the plant is cotton.

[0030] The invention also provides the use of the primer in preparing the RNA interference sequence of the cotton aphid gene. Through biological verification, the RNA interference sequence of the cotton aphid Armet gene of the invention can be used for the development of transgenic insect-resistant plants.

[0031] The present invention also provides a method for creating a cotton aphid-resistant plant strain, comprising inhibiting or silencing the expression of the Armet gene;

[0032] Preferably, the plant is cotton.

[0033] According to the method for creating the cotton aphid-resistant plant strain, the dsRNA and / or the primer for inhibiting the reproduction of cotton aphid are used.

[0034] The present invention provides an isolated cotton aphid Armet (Arginine rich, mutated in early stage of tumors) gene and a protein encoded by the gene, including an RNA interference sequence of the gene. After designing and synthesizing the dsRNA of the Armet gene interference sequence, the dsRNA is delivered into the cotton aphid by using the virus-induced gene silencing (VIGS) technology. The dsRNA, as a key elicitor of gene silencing, is first cut into 21-24 nt small interfering RNA (Small interfering RNA, siRNA) by a specific nuclease Dicer analog in the cell. The siRNA combines with the RNA recognition complex (RISC) to form a siRNA-RISC complex. Finally, the siRNA-RISC complex causes the degradation or translation inhibition of the mRNA through complementary pairing with the targeted mRNA, thereby achieving gene silencing. The inventors found that the expression level of the Armet gene in cotton aphids that fed on VIGS cotton plants was significantly reduced. They also found that after interfering with this gene, the number of offspring of cotton aphids was significantly reduced, ultimately leading to the decline of the population. This provides new ideas for controlling the development of cotton aphid populations and also provides a basis for achieving green control of cotton aphids and other Hemiptera insects.

[0035] Armet is crucial to the host adaptability of aphids. By interfering with the Armet gene of cotton aphids, the population of cotton aphids can be controlled, thereby achieving the purpose of preventing and controlling cotton aphids. At the same time, it provides an important molecular target for the green prevention and control of cotton aphids. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art.

[0037] Figure 1 It is a flow chart of the verification of the function of the Armet gene provided by the present invention.

[0038] Figure 2 It is a schematic diagram of the structure of the pEASY-T1 cloning vector provided by the present invention.

[0039] Figure 3This is the detection of the silencing efficiency of the target gene Armet of cotton aphids by VIGS cotton plants provided in Example 3 of the present invention. Virus-induced gene silencing (VIGS) technology was used to transfect cotton with a vector to knock down the expression of Armet. Armet represents cotton plants transfected with target gene disruptors, P1+P2 represents cotton plants transfected with empty vectors (pTRV1+pTRV2), and CK represents wild-type cotton plants. According to Tukey's HSD test, different letters indicate significant differences (P<0.05).

[0040] Figure 4 This is the functional analysis of Armet provided in Example 3 of the present invention. After VIGS knocked down the expression of Armet, the changes in the number of cotton aphid progeny were recorded. In the figure, Armet represents cotton plants transfected with target gene disruptors, P1+P2 represents cotton plants transfected with empty vectors (pTRV1+pTRV2), and CK represents wild-type cotton plants. According to Tukey's HSD test, different letters indicate significant differences (P<0.05). DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] The techniques used in the embodiments, including TRIzol method for RNA extraction, cDNA cloning, PCR amplification and detection, plasmid extraction, and VIGS plant construction, are all conventional techniques known to those skilled in the art. The instruments, equipment, reagents, etc. used can be obtained by those skilled in the art through public relations channels or commercial channels.

[0043] Based on the isolation and cloning of the Armet gene, the present invention also uses specific primers to synthesize the dsRNA of the Armet gene in vitro, and delivers the dsRNA to the cotton aphid by VIGS technology. Real-time fluorescence quantitative PCR (qPCR) detection found that the expression of the Armet gene was significantly inhibited. At the same time, the number of offspring of the F1 progeny after 7 days of VIGS treatment was counted, and the results showed that inhibiting the expression of the Armet gene significantly reduced the number of offspring of the cotton aphid, ultimately affecting the reproductive capacity and population development of the cotton aphid. The Armet gene can be used as an alternative gene for the cultivation of transgenic plants resistant to cotton aphids.

[0044] Example 1: Cloning and analysis of the cotton aphid Armet gene

[0045] 1. TRIzol RNA extraction

[0046] 1) Tissue lysis: Take 30 mg of cotton aphid tissue sample and place it in a 1.5 ml enzyme-free tube, pre-cool it with liquid nitrogen, and grind it with a grinding rod until it is ground into powder. Add 1000 μl of RNAiso plus lysis solution into the tube and let it stand at room temperature for 5 minutes.

[0047] 2) Centrifuge at 12000×g at 4℃ for 5 min.

[0048] 3) Transfer the supernatant to a new 1.5 ml RNA enzyme-free tube, add 200 μl chloroform, and shake vigorously to mix.

[0049] 4) Let stand at room temperature for 5 minutes.

[0050] 5) Centrifuge at 12000×g at 4℃ for 15 min.

[0051] 6) Transfer the supernatant to a new 1.5 ml RNA enzyme-free tube and add isopropanol equal to the volume of the supernatant. Invert and mix.

[0052] 7) Let stand at room temperature for 10 minutes.

[0053] 8) Centrifuge at 12000×g at 4℃ for 10 min.

[0054] 9) Discard the supernatant and keep the precipitate.

[0055] 10) Prepare 750 μl of anhydrous ethanol and 250 μl of RNase-free H2O to make 75% alcohol. Add to the tube. Invert.

[0056] 11) Centrifuge at 7900×g for 5 min at 4°C.

[0057] 12) Discard the supernatant and keep the precipitate.

[0058] 13) Open the centrifuge tube cover and dry it at room temperature in a clean bench for 4 minutes.

[0059] 14) Add an appropriate amount of RNase-free H2O water to dissolve, and store at -80°C after it is fully dissolved.

[0060] 2. cDNA cloning

[0061] Using PrimeScript from Takara Japan TM The total RNA extracted in step 1 was synthesized into a cDNA template using the RT Master Mix (perfect real time) kit (the specific steps were in accordance with the kit instructions).

[0062] 3. Primer Design

[0063] The Armet gene nucleic acid sequence (see SEQ ID NO. 1) was obtained based on genome sequencing, and primers were designed using Primer Premier 5.0 to verify the predicted open reading frame.

[0064] The nucleotide sequence of SEQ ID NO.1 is shown below, totaling 717 bp; the nucleotide sequence of CDS is 38-559 bp, totaling 522 bp.

[0065]

[0066] The primers designed and synthesized are as follows:

[0067] Upstream primer sequence Armet-F:

[0068]

[0069] Downstream primer sequence Armet-R:

[0070]

[0071] The primers were synthesized by Shanghai Shenggong Bioengineering Technology Service Co., Ltd.

[0072] 4. PCR Amplification

[0073] Using cotton aphid cDNA as a template, PCR amplification was performed using the above primers Armet-F and Armet-R. The PCR system was prepared according to the instructions of Ex Taq enzyme of Takara Company of Japan. PCR reaction conditions: 95℃ pre-denaturation for 3min; 95℃ denaturation for 30s, 58℃ annealing for 30s, 72℃ renaturation extension for 1min, 35 cycles; 72℃ extension for 10min, and the product was stored at 4℃. 1% agarose gel electrophoresis was used to detect the PCR product, and the electrophoresis results were observed under ultraviolet light. The correct fragment was cut and the target fragment was purified and recovered using the DNA gel recovery kit of AxyGen Company.

[0074] 5. Cloning of PCR Products

[0075] The recovered PCR product was connected to the pEASY-T1 vector according to the Beijing Quanshijin pEASY-T1 vector instructions (see Figure 2 ), the recombinant vector was transformed into Beijing Quanshijin competent cell T1, and cultured overnight in ampicillin (amp) resistant LB medium. After overnight culture, 8 positive clones were selected for PCR verification (system and conditions are the same as above), and fresh bacterial culture of clones that were positive for colony PCR amplification was sent to Shanghai Shenggong Bioengineering Technology Service Co., Ltd. for sequencing.

[0076] 6. Sequence Analysis

[0077] The Armet gene nucleotide sequence returned by the sequencing company was compared with the nucleotide sequence obtained by transcriptome sequencing using NCBI (https: / / www.ncbi.nlm.nih.gov / ) to verify its correctness. The comparison results showed that the sequencing nucleotide sequence was consistent with the transcriptome nucleotide sequence. The protein sequence of the gene was predicted and analyzed using ExPASy (http: / / web.expasy.org / translate / ) (see SEQ ID NO.2). The Armet gene open reading frame is 522bp in length, encoding 173 amino acid residues, with a predicted molecular mass of 20.3kDa and a theoretical isoelectric point of 6.6. The present invention further compares it with the four Armet amino acid sequences of alfalfa aphid, peach aphid, pea aphid and wheat bitail aphid, confirming that the protein isolated by the present invention has typical Armet protein characteristics.

[0078] The amino acid sequence of Armet protein (SEQ ID NO.2) is shown below, encoding 173 amino acids in total:

[0079]

[0080] Example 2: VIGS cotton plant construction

[0081] According to the Armet gene sequence obtained in Example 1, the dsRNA region was predicted by siDirect version 2.0 (http: / / sidirect2.rnai.jp / ), and specific amplification primers were designed using Primer Premier 5.0 for amplification of the dsRNA fragment of the Armet gene. The designed specific primers are as follows:

[0082] Upstream primer sequence dsArmet-F:

[0083]

[0084] Downstream primer sequence dsArmet-R:

[0085]

[0086] Using cotton aphid cDNA as a template, PCR amplification was performed using the above primers dsArmet-F and dsArmet-R. The PCR reaction system was prepared according to the instructions for use of Ex Taq enzyme from Takara, Japan. PCR reaction procedure: 95°C pre-denaturation for 3 min; 95°C denaturation for 30 s, 58°C annealing for 30 s, 72°C renaturation extension for 30 s, 35 cycles; 72°C extension for 10 min, and the product was stored at 4°C. PCR products were detected by 1% agarose electrophoresis, and the electrophoresis results were observed under ultraviolet light. The gel was cut and the target fragment was purified and recovered using the DNA gel recovery kit of AxyGen.

[0087] 1. Connect

[0088] (1) Enzyme digestion of PTRV2 vector

[0089] First, use endonuclease to perform single restriction digestion on the vector. The reaction system is as follows:

[0090]

[0091]

[0092] After mixing and centrifugation, incubate the enzyme digestion at 37℃ for ≥4h.

[0093] (2) Use AxyGen's DNA gel recovery kit to recover and purify the vector after enzyme digestion.

[0094] (3) Processing of carriers.

[0095] First, prepare the reaction solution ① according to the table below.

[0096]

[0097] Then, the purified vector was mixed with reaction solution ① at a ratio of 1:1 to prepare reaction solution ②.

[0098] (4) Treatment of purified PCR products.

[0099] Prepare the reaction solution ③ according to the table below.

[0100]

[0101] (5) Place two tubes of reaction solution: reaction solution ② and reaction solution ③, in a PCR instrument. The reaction procedure is: 37℃ for 30 min, 75℃ for 20 min. Then 70℃ for 3 min. During this process, open the PCR instrument and take 5 μl of reaction solution ② and add it to the centrifuge tube of reaction solution ③, that is, mix them in a 1:1 ratio. Then, cover the PCR instrument and react at 22℃ for 10 min, and then at 22℃∞.

[0102] 2. Transformation of E. coli

[0103] (1) Take 5 μl of the ligation product and add it to 50 μl of Trans1-T1 Phage Resistant competent cells.

[0104] (2) Mix by flicking gently, place on ice for 30 min, heat shock at 42°C for 30 s, and place on ice again for 2 min.

[0105] (3) Add 500 μl of LB liquid culture medium without antibiotics and place in a constant temperature shaker at 200 rpm and 37°C for 1 h.

[0106] (4) Spread 200 μl of bacterial solution onto LB solid medium containing kana and incubate at 37°C for 12-16 hours.

[0107] 3. Identification and sequencing of positive recombinants

[0108] In a clean bench, single clones were picked and placed in 500 μl of LB liquid culture medium containing kana, and the culture was shaken at 200 rpm and 37°C for 4-6 hours, and positive recombinants were identified by bacterial liquid PCR. The reaction system and procedure of bacterial liquid PCR were the same as those in Example 1.

[0109] After colony PCR identification, 200 μl of fresh bacterial solution was sent to GeneWeichi Biotechnology Co., Ltd. for sequencing.

[0110] 4. Plasmid Extraction

[0111] Plasmid extraction was performed using the TIANprep Mini Plasmid Kit from Tiangen.

[0112] (1) Add 500 μl of balancing solution BL to the adsorption column CP3 placed in the collection tube, centrifuge at 12,000 rpm for 1 min, discard the waste liquid, and put the adsorption column back into the collection tube for later use.

[0113] (2) Take 5 μl of overnight cultured bacterial solution, centrifuge at 12,000 rpm for 1 min, and discard the supernatant.

[0114] (3) Add 250 μl of solution P1 and vortex to fully suspend the precipitate.

[0115] (4) Add 250 μl of solution P2 and slowly and gently invert the centrifuge tube up and down 6-8 times.

[0116] (5) Add 350 μl of solution P3, immediately and gently invert the tube upside down 6-8 times to mix the solution thoroughly, and then centrifuge at 12000 rpm for 10 min.

[0117] (6) Use a pipette to transfer the supernatant to the adsorption column CP3, centrifuge at 12000 rpm for 1 min, discard the waste liquid, and put the adsorption column CP3 back into the collection tube.

[0118] (7) Add 600 μl of rinse solution PW to the column, centrifuge at 12,000 rpm for 1 min, and discard the waste solution.

[0119] (8) Repeat step (7).

[0120] (9) Incubate at 12,000 rpm for 2 min, discard the collection tube, open the lid of the adsorption column, and air dry at room temperature for 30 min.

[0121] (10) Place the adsorption column CP3 in a new centrifuge tube, add 50 μl of EB to the center of the adsorption membrane, leave at room temperature for 2 min, and centrifuge at 12,000 rpm for 2 min. Store the extracted plasmid in a -20°C refrigerator.

[0122] 5. Transformation of Agrobacterium

[0123] (1) Add 2.5 μl of plasmid to 100 μl of Agrobacterium tumefaciens, flick to mix, place on ice for 30 min, freeze in liquid nitrogen for 2 min, heat shock at 37°C for 1 min 30 s, and place on ice again for 5 min.

[0124] (2) Add 600 μl of LB liquid culture medium without antibiotics and culture at 28°C and 190 rpm for 4 h.

[0125] (3) Take 200 μl of the bacterial solution and spread it on LB solid medium containing kana, Rif, and SM. Incubate it upside down at 28°C for 48 h until colonies are visible.

[0126] (4) Pick a single clone and place it in 1 ml of LB liquid culture medium. Culture it for 16 h until the liquid becomes turbid.

[0127] (5) Identification of positive clones by colony PCR.

[0128] 6. Infection of cotton

[0129] (1) Shake the culture medium in a 1:100 ratio until OD600 ≈ 1.0.

[0130] (2) pTRV1 was mixed with pTRV2 and pTRV2 derivatives at a ratio of 1:1, and centrifuged at 3000 rpm for 5 min at room temperature.

[0131] (3) Discard the supernatant and use an equal volume of staining buffer (to maintain OD600≈1.0). Incubate at room temperature for 2-4 hours. (Preparation of staining buffer: dissolve 1 ml 1M MgCl2, 1 ml 1M MES, 100 μl 200 mM acetosyringone in 100 ml ddH2O, prepare and use immediately).

[0132] (4) Select cotton with two flattened cotyledons (about 7-10 days old) for infection. Use a needle to scratch the epidermis on the back of the cotyledons, leaving 3-4 "X" marks on each cotyledon. Place your hand against the front of the leaf, draw the bacterial solution with a syringe, and inject it from the position marked with "X" on the back of the leaf.

[0133] (5) The dyed cotton was dark-treated for 24 hours and cultured in an artificial climate room at a temperature of (26±1)°C, a humidity of 70% to 80%, and a photoperiod of L:D=14:10. When the cotton grew to the 6-leaf stage, it was used for the bioassay test.

[0134] Example 3: Interference efficiency detection and bioassay test

[0135] Twenty adult aphids were placed on the second leaf in the 6-leaf stage of cotton as a group, and a micro-insect cage was fixed on the leaf to prevent aphids from escaping. When the adult aphids produced 25 nymphs, the adult aphids were removed. After 7 days, the litter birth rate was counted and the T1 generation of cotton aphids were collected for RT-qPCR. Six groups were repeated, with a total of 3 replicates.

[0136] Test results and analysis:

[0137] (1) Armet silencing efficiency

[0138] Compared with the control group (cotton aphids feeding on wild-type cotton plants), the expression of the Armet gene in cotton aphids feeding on VIGS cotton plants decreased significantly by 22%, indicating that the interference sequence of the Armet gene in cotton aphids and VIGS technology can significantly inhibit the expression of the Armet gene ( Figure 3 ).

[0139] (2) The number of offspring of cotton aphids feeding on VIGS cotton plants was significantly reduced by 38% ( Figure 4 ). This indicates that the reduction of Armet expression can significantly inhibit the reproduction of cotton aphids and reduce the cotton aphid population. Therefore, the RNA interference sequence provided by the present invention can be applied to the development of transgenic cotton aphid-resistant plants. Further development of its protein can be applied to the biological control of cotton aphids.

[0140] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. Armet protein, characterized in that The Armet protein has any of the following amino acid sequences: (1) the amino acid sequence shown in SEQ ID NO.2; (2) an amino acid sequence having at least 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% identity with the amino acid sequence shown in SEQ ID NO. 2, wherein the protein has the function of affecting the reproduction of cotton aphids; (3) An amino acid sequence obtained by replacing and / or deleting and / or adding one or more amino acid residues in the amino acid sequence shown in SEQ ID NO. 2, wherein the protein has the function of affecting the reproduction of cotton aphids.

2. A gene encoding Armet protein, characterized in that: The Armet gene contains the nucleotide sequence at positions 38-559 shown in SEQ ID NO.1; Preferably, the Armet gene contains the nucleotide sequence shown in SEQ ID NO.

1.

3. A biological material containing the Armet gene, characterized in that: The biological material is an expression cassette, a vector, a host cell or a recombinant bacterium; Preferably, the host cell is a host cell that can develop into a plant individual and / or a host cell that cannot develop into a plant individual.

4. A dsRNA for inhibiting the reproduction of cotton aphids, characterized in that: It is the dsRNA of the Armet gene; Preferably, the nucleotide sequence of the dsRNA includes the nucleotide sequence amplified by primers SEQ ID NO.5-6.

5. A primer for amplifying the dsRNA according to claim 4; Preferably, it includes SEQ ID NO. 5-6.

6. Use of the Armet protein according to claim 1, the gene encoding the Armet protein according to claim 2, the biological material containing the Armet gene according to claim 3, or the dsRNA for inhibiting the reproduction of cotton aphid according to claim 4 in any of the following: 1) Control insects; Preferably, reducing the litter size of cotton aphids; 2) Transgenic plant breeding; 3) Preparation of pesticides; Preferably, the insect is an Aphididae animal, more preferably an Aphididae animal, and even more preferably a cotton aphid; Preferably, it is preferably used in transgenic plants resistant to cotton aphids; Preferably, it is used to inhibit the reproduction of cotton aphids and reduce the population of cotton aphids.

7. The use according to claim 6, characterized in that: The plant is cotton.

8. Use of the primers according to claim 5 in preparing RNA interference sequences of cotton aphid genes.

9. A method for creating a cotton aphid-resistant plant strain, characterized in that: Including inhibiting or silencing the expression of Armet gene; Preferably, the plant is cotton.

10. The method for creating a cotton aphid-resistant plant strain according to claim 9, characterized in that: Using the dsRNA for inhibiting the reproduction of cotton aphids as described in claim 4 and / or the primers as described in claim 5.

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