Short peptide capable of improving the ability of plants to resist viruses and application thereof

Abstract

The present application relates to the field of agricultural biology, and particularly relates to a short peptide capable of improving the plant antiviral ability and application thereof.The present application provides a short peptide capable of improving the plant antiviral ability, and the amino acid sequence of the short peptide is any one or several of the sequences as shown in SEQ ID NO.3-SEQ ID NO.8.The present inventors obtain six short peptides by extracting a large number of experiments using field infected virus disease cucumber, pepper, tomato and tobacco plants;then the leaves of Nicotiana benthamiana are externally sprayed with the six short peptides, and then inoculated with virus TMV, the results show that the external spraying of the six short peptides is not conducive to the infection of TMV;the leaves of cucumber are externally sprayed with the six short peptides, and then inoculated with virus CMV, the results show that the external spraying of the six short peptides is not conducive to the infection of CMV, which indicates that the six short peptides can inhibit the infection of viruses TMV and CMV to a certain extent.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of agricultural biology, and particularly relates to a short peptide capable of improving the anti-virus ability of plants and application thereof. BACKGROUND

[0002] Plant virus disease is the second largest plant disease after plant fungal disease, which is highly specialized, has various types, is mainly transmitted by insects, has a fast transmission speed, has a high virus mutation rate, and is difficult to control. In recent years, the economic loss caused by plant virus infection in agricultural production in China is as high as 60 billion US dollars, which seriously endangers the growth and development of crops and their economic value. The occurrence of plant virus disease is affected by many factors, such as strain type, host plant, transmission vector, environmental conditions and human operation. The method for preventing and controlling plant virus disease is still under exploration, and there is no specific drug for plant virus disease at present. At present, the comprehensive prevention and control method is widely used in agricultural production, including plant quarantine, resistant varieties, crop rotation, and control of infectious agents (aphids, etc.), but the harm caused by virus disease cannot be completely solved. Therefore, activating the immune response of plants by using certain means is still an important research direction for the prevention and control of plant virus disease in the future.

[0003] Small signaling peptides (SSPs) as a new type of important signaling molecules can not only transmit information between cells at a short distance, but also participate in the regulation of plant response to non-biological stress signals through long-distance information transmission. There are some plant endogenous secretory peptides in plants, which are released from cells attacked by fungi, bacteria and other pathogens into the extracellular space, and can trigger plant immune response. In addition, some secretory peptides can also regulate plant immunity through the hormone pathway. However, the function of plant endogenous short peptides in plant anti-virus response is still rarely studied. SUMMARY

[0004] The present application aims to provide a short peptide capable of improving the anti-virus ability of plants and application thereof to solve the problems existing in the prior art. The present application uses cucumber, pepper, tomato and tobacco plants infected with virus disease in the field to extract 6 short peptides. After spraying the 6 short peptides exogenously and inoculating viruses, the effects of the short peptides on plant resistance to virus disease are studied, and it is found that the 6 short peptides can enhance the resistance of plants to viruses and can be used for the preparation of anti-virus products.

[0005] To achieve the above object, the present application provides the following scheme:

[0006] The present application provides a short peptide capable of improving the anti-virus ability of plants, wherein the amino acid sequence of the short peptide is any one or several of the sequences as shown in SEQ ID NO. 3-SEQ ID NO. 8.

[0007] The virus is tobacco mosaic virus and / or cucumber mosaic virus.

[0008] The present application provides a nucleic acid molecule encoding the short peptide.

[0009] The present application provides the use of the short peptide or the nucleic acid molecule in the preparation of a product for improving the virus resistance of plants, the virus being tobacco mosaic virus and / or cucumber mosaic virus.

[0010] Preferably, the product comprises a virus inhibitor or an antiviral drug.

[0011] The present application provides a virus inhibitor comprising the short peptide; the virus being tobacco mosaic virus and / or cucumber mosaic virus.

[0012] Preferably, the virus inhibitor further comprises an excipient.

[0013] The present application provides the use of the short peptide, the nucleic acid molecule or the virus inhibitor in inhibiting the infection of a virus, the virus being tobacco mosaic virus and / or cucumber mosaic virus.

[0014] The present application provides a method for inhibiting the infection of a virus in plants, comprising the step of spraying the short peptide or the virus inhibitor on the plants to be treated; the virus being tobacco mosaic virus and / or cucumber mosaic virus.

[0015] Further preferably, the spraying position is the leaf of the plants to be treated.

[0016] Further preferably, the plants to be treated are tobacco and cucumber.

[0017] The present application provides the use of the short peptide, the nucleic acid molecule or the virus inhibitor in improving the virus resistance of plants, the virus being tobacco mosaic virus and / or cucumber mosaic virus.

[0018] The present application provides a method for improving the virus resistance of plants, comprising the step of spraying the short peptide or the virus inhibitor on the plants to be treated; the virus being tobacco mosaic virus and / or cucumber mosaic virus.

[0019] Further preferably, the spraying position is the leaf of the plants to be treated.

[0020] Further preferably, the plants to be treated are tobacco and cucumber.

[0021] The present application discloses the following technical effects:

[0022] The present application provides a kind of short peptide capable of improving the ability of plant to resist virus, the amino acid sequence of the short peptide is any one or several of the sequence described in SEQ ID NO.3-SEQ ID NO.8.The inventor obtains 6 short peptides by a large number of experiments using cucumber, pepper, tomato and tobacco plants infected with virus disease in the field extraction;Afterwards, respectively, the leaf of Nicotiana benthamiana is sprayed with 6 short peptides, and then inoculated with virus TMV, the results show that the infection of TMV is not conducive after spraying 6 short peptides;Afterwards, the leaf of cucumber is sprayed with 6 short peptides, and then inoculated with virus CMV, the results show that the infection of CMV is not conducive after spraying 6 short peptides, which indicates that the 6 short peptides can inhibit the infection of virus TMV and CMV to some extent.The results of the embodiments of the present application show that the plant defense response to viral disease is activated by spraying short peptides on plants, and the infection of virus on plants is inhibited, therefore, the 6 short peptides can be used to prepare antiviral products, so as to inhibit the infection of virus on plants, and compared with chemical pesticides, the short peptides provided by the present application are non-toxic and non-polluting, efficient and convenient, and have important application value. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced as follows, and obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0024] Figure 1 The infection situation diagram of Nicotiana benthamiana inoculated with TMV after spraying 8 short peptides, wherein A is the statistical diagram of system leaf virus fluorescence accumulation of Nicotiana benthamiana, and B is the result diagram of system leaf virus protein accumulation level of Nicotiana benthamiana;

[0025] Figure 2 The infection situation diagram of cucumber inoculated with CMV after spraying 8 short peptides, wherein A is the symptom diagram of cucumber infected by virus, and B is the result diagram of system leaf virus protein accumulation level of cucumber;

[0026] Figure 3 The disease occurrence diagram of Nicotiana benthamiana inoculated with TMV for 10 days after spraying 8 short peptides, wherein A is the statistical diagram of disease incidence of Nicotiana benthamiana inoculated with TMV for 10 days, and B is the statistical diagram of disease index of Nicotiana benthamiana inoculated with TMV for 10 days;

[0027] Figure 4Figures of disease incidence of cucumber inoculated with CMV 15 days after spraying 8 short peptides respectively; wherein, A is a statistical chart of the investigation results of the incidence of cucumber inoculated with CMV 15 days; B is a statistical chart of the investigation results of the disease index of cucumber inoculated with CMV 15 days. DETAILED DESCRIPTION

[0028] Various exemplary embodiments of the present application will now be described in detail, which should be considered to be illustrative of the application and not restrictive of the application. It will be appreciated that the detailed description is not intended to limit the application to certain aspects, features, and embodiments, but rather to provide a more thorough description of the various aspects, features and embodiments of the application.

[0029] It should be understood that the terms used in the specification of the present application are merely used to describe particular embodiments and are not intended to limit the present application. In addition, for numerical ranges in the present application, it should be understood that each intermediate value between the upper limit and the lower limit of the range is specifically disclosed. Each intermediate value within any stated value or stated range, and any other stated value or intermediate value within the stated range, is also included within the present application. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, the preferred methods and materials are described. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials in connection with which the documents are cited. In case of conflict between the content of the specification and that of any document incorporated herein by reference, the content of the specification prevails.

[0031] Various modifications and changes can be made to the specific embodiments of the present application described herein without departing from the scope or spirit of the application. Other embodiments of the application will be apparent to those of ordinary skill in the art from the description and examples presented herein. The description and examples are illustrative of the application and are not intended to limit the scope of the application.

[0032] As used herein, the terms "comprise", "comprising", "include", "including", "have", "having" and the like are open-ended and do not exclude additional, unrecited elements or method steps.

[0033] Discovery of 8 short peptides

[0034] The inventors of the present application found 8 short peptides from cucumber, pepper, tomato and tobacco infected with virus diseases in the field through a large number of experiments. The specific steps are as follows:

[0035] 1. Extraction of intercellular fluid proteins of cucumber, pepper, tomato and tobacco leaves

[0036] (1) Take the cucumber, pepper, tomato and tobacco leaves infected with virus disease in the field, clean the surface with ddH2O and dry the surface with a water-absorbing paper.

[0037] (2) After step (1) is completed, immerse the cleaned leaves in a solution containing 0.1% protease inhibitor, and use a vacuum pump to completely immerse the solution into the leaves.

[0038] (3) After step (2) is completed, dry the liquid on the surface of the leaves with a water-absorbing paper, place them in a syringe (20 mL) and then in a centrifuge tube (50 mL), centrifuge at 4°C and 1000g for 1 min, and collect the liquid phase.

[0039] (4) Add the liquid phase collected in step (3) to a Merck Millipore ultrafiltration tube (0.5 mL, 3KDa), centrifuge at 4°C and 6000g for 1 min; collect the effluent in a new centrifuge tube (2 mL), then use a freeze-drying instrument to concentrate the liquid to a dry powder; finally, dissolve the dry powder with 200 μL of a solution containing 0.1% protease inhibitor to obtain the intercellular liquid protein of cucumber, pepper, tomato and tobacco leaves.

[0040] 2. Desalination

[0041] Take a centrifuge tube (2 mL), add 100 μL of intercellular liquid protein of cucumber, pepper, tomato and tobacco leaves and 200 μL of a solution containing 0.5% TFA and 0.5% acetonitrile in water to obtain the sample.

[0042] First, activate the C 18 Desalination column, then use 400-600 μL of a solution containing 0.1% TFA and 1% acetonitrile in water to balance the desalination column; then add the sample (intercellular liquid protein of cucumber, pepper, tomato and tobacco leaves obtained in step "1, extraction of intercellular liquid protein of cucumber, pepper, tomato and tobacco leaves") to the C 18 Desalination column, and make the sample flow slowly into the C 18 Desalination column, and make the sample flow slowly into the C 18 Desalination column, and make the sample flow slowly into the C 18 Desalination column, and make the sample flow slowly into the C 18 Desalination column, and make the sample flow slowly into the C

[0043] 3. LCMS / MS analysis of polypeptides

[0044] The detection system is a Thermo Easy-nLC 1200 (Thermo Scientic, P / N LC140) coupled with an Orbitrap Exploris 480 (Thermo Scientic, P / N BRE725533). The dried powder from step “2, desalting” was dissolved using 10 pl of mobile phase A (0.1% formic acid in water) and 5 pL was injected. Peptides were trapped on a 10 pL / min flow rate for 3 min on a trap column (PepMap C 18 18, 100 pm x 2 cm) followed by gradient elution chromatography on a nanoflow analytical column (PepMap C 18 18, 75 pm x 25 cm). The separation gradient was 60 min with mobile phase B (0.1% formic acid in acetonitrile) rising from 5% to 30%. The flow rate was 200 nL / min and the column temperature was 55 °C. The ion source spray voltage was 2.0 kV, the mass spectrometer heated capillary was set to 320 °C and the data-dependent mode was used for automatic switching between MS and MS / MS acquisition. Full scan MS was performed using an Orbitrap for a single scan with a scan range of m / z 100-1600 and a resolution set to 70000 (at m / z 200). The maximum ion injection time was 50 ms and the automatic gain control (AGC) was set to 5 x 10 5 The top 15 precursor ions with intensity meeting the MS / MS fragmentation condition were fragmented using higher energy C-trap dissociation (HCD) and scanned using an orbitrap with a scan resolution set to 17500. The scan range was automatically controlled according to the mass-to-charge ratio of the precursor ion, with the lowest scan range fixed at m / z = 100 and the highest up to 2000. The minimum ion intensity value for MS / MS was set to 13000. The maximum ion injection time was 100 ms and the AGC control was set to 2.0 x 10 5 The precursor ion selection window was set to 1.6 Da. MS / MS acquisition was performed for ions with 1, 2, 3, and 4 charges, with dynamic exclusion set to 1 MS / MS per precursor ion within 10 seconds, followed by 40 s exclusion, with a 30% collision energy.

[0045] 4. Database searching and polypeptide identification

[0046] The raw data obtained from step "3, LCMS / MS analysis of polypeptide" was processed and spectrum analyzed by PEAKS software. PEAKS can perform De Novo sequencing, protein identification (PEAKSDB). The parameters were set as follows when performing De novo sequencing and database searching: Marinobacterium profundum protein database, non-enzyme digestion, the tolerance of primary mass spectrum was 10 ppm, the tolerance of secondary mass spectrum was 0.02 Da, no fixed modification, variable modification was set as methionine oxidation, N-terminal acetylation, the charge was set as +1, +2, +3, +4. The false discovery rate (FDR) of peptide identification was set as 1%. For the results of De novo sequencing, ALC (%) stands for average local confidence, the confidence of De novo sequencing data results, generally greater than 80% is more reliable, greater than 95% is very reliable. Finally, 8 short peptides SJPep1-SJPep8 were found, the amino acid sequences of short peptides SJPep1-SJPep8 are shown as SEQ ID NO. 1-SEQ ID NO. 8, and are as follows:

[0047] SJPep1: KHSGPSPSGDGH, SEQ ID NO. 1;

[0048] SJPep2: KHASGPSMRGPGH, SEQ ID NO. 2;

[0049] SJPep3: AVQSKPPSKRDPPKMQTD, SEQ ID NO. 3;

[0050] SJPep4: AVHSTPPSKRPPPKMQTD, SEQ ID NO. 4;

[0051] SJPep5: EAHLDY(SO3H)IY(SO3H)TQHHNHP, SEQ ID NO. 5;

[0052] SJPep6: HLDY(SO3H)IY(SO3H)TQSINNNHP, SEQ ID NO. 6;

[0053] SJPep7: ECLMRRTLEAHLDY(SO3H)IY(SO3H)TQRHK, SEQ ID NO. 7;

[0054] SJPep8: CLKRRMVAEAHLDY(SO3H)IY(SO3H)TQHKPK, SEQ ID NO. 8;

[0055] The structural formula of Y(SO3H)IY(SO3H)TQ (SEQ ID NO. 9) is [H-Tyr(SO3H)-Ile-Tyr(SO3H)-Thr-Gln-OH].

[0056] Application of eight short peptides SJPep1-SJPep8 in plant antiviral

[0057] Preparation of short peptide SJPep1-SJPep8 dilutions: The eight short peptides SJPep1-SJPep8 in this embodiment were synthesized by Shengong Bioengineering (Shanghai) Co., Ltd. The short peptide SJPep1-SJPep8 dilutions were obtained by diluting the short peptides SJPep1-SJPep8 with sterile water, and the concentration of the short peptides SJPep1-SJPep8 in the short peptide SJPep1-SJPep8 dilutions was 300 μg / mL.

[0058] 1. Take 30 Nicotiana benthamiana seedlings grown for 3 weeks, and randomly divide them into an experimental group and a control group, 15 seedlings in each group, with 3 replicates. Take 30 cucumber seedlings grown for 3 weeks, and randomly divide them into an experimental group and a control group, 15 seedlings in each group, with 3 replicates. Then, the above groups are treated as follows:

[0059] Experimental group: use one of the short peptide SJPep1-SJPep8 dilutions to spray the whole plant of the Nicotiana benthamiana seedlings or cucumber seedlings, spray until the whole plant is wet, and sequentially record as SJPep1-SJPep8. Then, spray the short peptide dilution again after 3-5 days, and spray a total of 3 times.

[0060] Control group: use sterile water to spray the whole plant of the Nicotiana benthamiana seedlings or cucumber seedlings, spray until the whole plant is wet, and record as CK. Then, spray sterile water again after 3-5 days, and spray a total of 3 times.

[0061] 2. After step 1 is completed, use Agrobacterium infiltration to inoculate TMV virus (tobacco mosaic virus) or CMV virus (cucumber mosaic virus), and the specific steps are as follows:

[0062] (1) TMV-GFP infectious clone (provided by Ningbo University Institute of Plant Virology, disclosed in the literature "Agroinoculation as a simple method of plant virus vector infection" (Jia Hongge, Pang Yongqi, Fang Rongxiang. Agroinoculation as a simple method of plant virus vector infection (English) [J]. Acta Botanica Sinica, 2003, (07): 770-773.), the TMV-GFP infectious clone in this application is named Agrobacterium containing p35S-30B: :GFP in the literature, and a commitment to issue 20 years) is inoculated into 10 mL YEP liquid medium (containing 100 μg / mL kanamycin sulfate and 20 μg / mL rifampicin), 28℃ oscillation culture for 12-16h, then 10000rpm centrifugal 1min, collect the precipitate. Then resuspend with tobacco immersion liquid (10mL tobacco immersion liquid is composed of 1mL 100mM concentration of MES solution, 0.1mL 1M concentration of MgCl2 solution, 20μL 2mM concentration of As solution and 8.88mL ddH2O), dilution to OD 600nm 0.0004 of TMV virus liquid.

[0063] According to the above steps, replace the TMV-GFP infectious clone with the CMV-GFP infectious clone (provided by Ningbo University Institute of Plant Virology, disclosed in the literature "Construction of Cucumber Mosaic Virus Transgenic Replication System", (Wang Lin, Cheng Xiaodong, Lu Ran, et al. Construction of Cucumber Mosaic Virus Transgenic Replication System [J]. Journal of Zhejiang University of Technology (Natural Science Edition), 2020, 43(02): 262-266.), specifically, mix the Agrobacterium containing plasmid pCB301-R1, Agrobacterium containing pCB301-R2 and Agrobacterium containing pCB301-R3-gfp in the literature according to the volume ratio of 1:1:1, and a commitment to issue 20 years), to obtain OD 600nm 0.06 of CMV virus liquid.

[0064] (2) Take the Nicotiana benthamiana seedlings and cucumber seedlings completed in step 1, and inject 0.2mL virus liquid (TMV-GFP virus liquid or CMV-GFP virus liquid) into the plant leaves with a sterile syringe, the injection area is about 1cm 2 , and the injection position is the second round of leaves of Nicotiana benthamiana or the cotyledon of cucumber seedlings.

[0065] 3. After completing step 2, place the Nicotiana benthamiana seedlings and cucumber seedlings in a 25℃ incubator for 10-15 days.

[0066] 4. After completing step 3, observe the viral infection status (TMV-GFP can be observed under a UV lamp for viral fluorescence; however, CMV-GFP fluorescence was not very obvious, so it was not observed under a UV lamp, and bright-field symptom photos were taken instead) and phenotype. The observation results are as follows: Figure 1 A and Figure 2 As shown in Figure A. The results showed that compared with the control group, the experimental group had significantly less fluorescent accumulation of tobacco virus, taller cucumber seedlings, and significantly weaker viral infection symptoms. Therefore, the application of short peptides SJPep1-SJPep8 can reduce the accumulation of tobacco virus and alleviate viral infection symptoms.

[0067] 5. After completing step 3, perform Western blotting on the tobacco seedlings and cucumber seedlings respectively, and determine the sample loading amount using Ponceau S (PSS) or Coomassie Brilliant Blue (CBB) staining. The specific steps are as follows:

[0068] (1) Extraction of total protein

[0069] After completing step 3, inoculation leaves or system leaves (system leaves are the upper leaves of the inoculation leaves) of three seedlings from the control group and the experimental group (tobacco Benedict seedlings and cucumber seedlings) were randomly selected and ground into powder in liquid nitrogen. Then, 0.2 g of powder was placed in a 2 mL sterile centrifuge tube, and 0.2 mL of cell lysis buffer (containing 200 mM NaCl, 1.0 mM EDTA, 1.0 mM DTT (pH 7.4) and 20 mM Tris-HCl buffer) was added. The mixture was vortexed and incubated on ice for 20 min. After that, the mixture was centrifuged at 4 °C and 14000 g for 10 min, and the supernatant was collected. 0.2 mL of the supernatant was mixed with 50 μL of loading buffer (GenScript, Beijing) in a 1.5 mL sterile centrifuge tube to obtain a mixture. The mixture was boiled in a water bath for 5 min, then incubated on ice for 5 min, and centrifuged at 4 °C and 14000 g for 10 min to obtain the processed protein mixture sample.

[0070] (2) Western blotting

[0071] (2-1) The protein mixture obtained in step (1) was electrophoresed in an SDS-PAGE gel (GenScript, Beijing) until the marker (Takara, Shanghai) showed the separation of the target band (GFP molecular weight is about 27kD).

[0072] (2-2) When using Coomassie Brilliant Blue staining method (CBB) to calibrate the loading amount, two pieces of SDS-PAGE gel with the same loading amount need to be electrophoresed in step (2-1), one for membrane transfer and the other for Coomassie Brilliant Blue staining. The gel to be stained is stained using a protein stainer (GenScript, Beijing), and after the staining is completed, the SDS-PAGE gel is taken out and photographed.

[0073] (2-3) After completing step (2-1), membrane transfer is performed. Before membrane transfer, the nitrocellulose membrane is soaked in the membrane transfer buffer, and in the membrane transfer instrument (GenScript, Beijing), a sponge pad, a protein gel, a nitrocellulose membrane, and a sponge pad are placed from the negative electrode to the positive electrode, respectively, and attention is paid to expel the air bubbles in the gap, and the membrane is transferred at a constant current of 0.3 A for 14 min.

[0074] (2-4) After the membrane transfer is completed, the nitrocellulose membrane is placed in the prepared Ponceau S dyeing solution (1L Ponceau S dyeing solution is prepared as follows: 0.1g Ponceau S, 5mL acetic acid and 95mL ddH2O are mixed, and then ddH2O is added to 1L), and shaken on a horizontal shaker until there are obvious red bands, the Ponceau S is discarded, and the membrane is washed with pure water until the red background disappears and the protein bands are clearly visible. The thickness of each sample is compared to ensure that the loading amount is consistent, and a photograph is taken. Then the membrane is washed with pure water until the red bands almost disappear, and the membrane is placed in 5% (m / V) skimmed milk prepared with 1×PBS for 1h on a horizontal shaker.

[0075] (2-5) After the blocking is completed, the blocking solution is discarded, and the membrane is washed with 1×PBS three times for 10 min each time; 5% (m / V) skimmed milk containing GFP antibody is added, and the antibody to skimmed milk ratio is 1:40000, and the mixture is incubated on a horizontal shaker for 1h; the primary antibody is discarded, and the membrane is washed with 1×PBS three times for 10 min each time; 5% (m / V) skimmed milk containing the corresponding secondary antibody is added, and the antibody to skimmed milk ratio is 1:40000, and the mixture is incubated on a horizontal shaker for 1h; the secondary antibody is discarded, and the membrane is washed with 1×PBS three times for 10 min each time.

[0076] (2-6) The PBS is discarded, the membrane is placed in a color developing bag, color developing solution is added, the color developing solution is evenly taken out, color development is performed in the dark, and exposure is performed in an AI600 instrument, and the detection results are shown in B of Figure 1 and B of Figure 2 The results show that compared with the control group, the accumulation amount of virus in the experimental group is significantly reduced.

[0077] 6、After completing step 3, the disease conditions of each group are counted, the disease index and the control effect are calculated.

[0078] (1) Virus disease classification standard According to the tobacco virus disease severity classification standard (national standard GB / T23222-2008), the classification investigation is carried out in units of strains, and the specific contents are as follows:

[0079] 0 level: no disease in whole plant;

[0080] 1 level: heart leaf vein is clear or leaf, distortion, and disease strain has no obvious dwarfing;

[0081] 3 level: 1 / 3 leaf mosaic, distortion, or disease strain dwarfing is more than 3 / 4 of normal plant height;

[0082] 5 level: 1 / 3 to 1 / 2 leaf mosaic, or a few leaf deformation, or main vein blackening, or slight wilting, or disease strain dwarfing is 2 / 3 to 3 / 4 of normal plant height;

[0083] 7 level: 1 / 2 to 2 / 3 leaf mosaic, or deformation or main lateral vein necrosis, wilting, and disease strain dwarfing is 1 / 2 to 2 / 3 of normal plant height;

[0084] 9 level: whole plant leaf mosaic, severe deformation, wilting or necrosis, or disease strain dwarfing is more than 1 / 2 of normal plant height.

[0085] (2) The control effect of each short peptide on TMV or CMV

[0086] The calculation is carried out according to the following formula.

[0087] Disease index = 100 x ∑ (number of strains of each level x relative level number) / (total number of strains investigated x 9);

[0088] Relative control effect (%) = 100 x (disease index of control group - disease index of treatment group) / disease index of control group.

[0089] The disease incidence investigation of Nicotiana benthamiana seedlings after TMV virus inoculation for 10 days in each treatment group is shown in A of Figure 3 . The results show that the TMV disease incidence after SJPep1 treatment decreases by 69.77%, the TMV disease incidence after SJPep2 and SJPep5 treatment decreases by 62.79%, the TMV disease incidence after SJPep3 and SJPep8 treatment decreases by 65.12%, the TMV disease incidence after SJPep4 treatment decreases by 72.09%, and the TMV disease incidence after SJPep6 and SJPep7 treatment decreases by 58.14%.

[0090] The disease index investigation of Nicotiana benthamiana seedlings after TMV virus inoculation for 10 days in each treatment group is shown in Figure 3The relative control effects of the short peptides on TMV were obtained by the disease index, as shown in B of FIG. 6B. The results show that the relative control effect of SJPep1 on TMV is 70.59%, the relative control effect of SJPep2 on TMV is 63.64%, the relative control effect of SJPep3 on TMV is 65.24%, the relative control effect of SJPep4 on TMV is 79.68%, the relative control effect of SJPep5 on TMV is 62.57%, the relative control effect of SJPep6 on TMV is 60.43%, the relative control effect of SJPep7 on TMV is 59.36%, and the relative control effect of SJPep8 on TMV is 60.96%.

[0091] The disease incidence of the cucumber seedlings after being inoculated with CMV for 15 days is shown in A of FIG. 7A. The results show that the CMV disease incidence after SJPep1 treatment is decreased by 69.05%, the CMV disease incidence after SJPep2 treatment is decreased by 64.29%, the CMV disease incidence after SJPep3 treatment is decreased by 52.38%, the CMV disease incidence after SJPep4 treatment is decreased by 61.90%, the CMV disease incidence after SJPep5 treatment is decreased by 59.52%, the CMV disease incidence after SJPep6 treatment is decreased by 54.76%, the CMV disease incidence after SJPep7 treatment is decreased by 57.14%, and the CMV disease incidence after SJPep8 treatment is decreased by 59.52%. Figure 4 The disease index of the cucumber seedlings after being inoculated with CMV for 15 days is shown in B of FIG. 7B. The relative control effects of the short peptides on CMV were obtained by the disease index. The results show that the relative control effect of SJPep1 on CMV is 71.35%, the relative control effect of SJPep2 on CMV is 66.15%, the relative control effect of SJPep3 on CMV is 55.21%, the relative control effect of SJPep4 on CMV is 63.54%, the relative control effect of SJPep5 on CMV is 63.02%, the relative control effect of SJPep6 on CMV is 59.90%, the relative control effect of SJPep7 on CMV is 61.46%, and the relative control effect of SJPep8 on CMV is 64.06%.

[0092] Figure 4 In summary, the short peptides SJPep1-SJPep8 can inhibit the infection of TMV when used for exogenous spraying of N. benthamiana. The short peptides SJPep1-SJPep8 can inhibit the infection of CMV when used for exogenous spraying of cucumber, i.e., the short peptides SJPep1-SJPep8 can inhibit the infection of viruses (such as TMV and CMV) to a certain extent.

[0093] In summary, the short peptides SJPep1-SJPep8 can inhibit the infection of TMV when used for exogenous spraying of N. benthamiana. The short peptides SJPep1-SJPep8 can inhibit the infection of CMV when used for exogenous spraying of cucumber, i.e., the short peptides SJPep1-SJPep8 can inhibit the infection of viruses (such as TMV and CMV) to a certain extent.

[0094] ​The above described embodiments are only to illustrate the preferred modes of the present application, and are not intended to limit the scope of the present application. Any modification and improvement made by those skilled in the art to the technical solutions of the present application without departing from the design spirit of the present application shall fall within the protection scope of the present application as defined by the claims.

Claims

1. Use of a short peptide for the preparation of a product for increasing the antiviral capacity of a plant, characterized in that, The amino acid sequence of the short peptide is shown as SEQ ID NO. 3; the improvement of the plant's ability to resist viruses is by spraying the plant; the virus is tobacco mosaic virus; the plant is Nicotiana benthamiana; or the virus is cucumber mosaic virus; the plant is cucumber.

2. Use according to claim 1, characterized in that, The product comprises a virus inhibitor or an antiviral drug.

3. Use of a short peptide for inhibiting viral infection, characterized in that, The amino acid sequence of the short peptide is shown as SEQ ID NO. 3; the inhibition of viral infection is by spraying the plant; the virus is tobacco mosaic virus; the plant is Nicotiana benthamiana; or the virus is cucumber mosaic virus; the plant is cucumber.

4. A method of inhibiting infection of a plant by a plant virus, characterized by, The product comprises a virus inhibitor or an antiviral drug.

5. Use of a short peptide for increasing the ability of a plant to resist viruses, characterized in that, The amino acid sequence of the short peptide is shown as SEQ ID NO. 3; the inhibition of viral infection is by spraying the plant; the virus is tobacco mosaic virus; the plant is Nicotiana benthamiana; or the virus is cucumber mosaic virus; the plant is cucumber.

6. A method for improving the ability of a plant to resist viruses, characterized by, The product comprises a virus inhibitor or an antiviral drug. The amino acid sequence of the short peptide is shown as SEQ ID NO. 3; the inhibition of viral infection is by spraying the plant; the virus is tobacco mosaic virus; the plant is Nicotiana benthamiana; or the virus is cucumber mosaic virus; the plant is cucumber.

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