Application of Bacillus Velezii Bv-6 in the prevention and control of plant viruses

Abstract

The present invention belongs to the technical field of microbial pesticides, and specifically relates to the application of Bacillus velezensis Bv‑6 in preventing and controlling plant viruses. The purpose of the present invention is to provide a new option for biological control of plant viral diseases. The technical solution of the present invention is the application of Bacillus velezensis Bv‑6 in preventing and controlling plant viral diseases, and the preservation number of Bv‑6 is CCTCC No: M20191106. The present invention first discovered that Bacillus velezensis Bv‑6 fermentation liquid and its wettable powder can effectively prevent and control plant viral diseases caused by tobacco mosaic virus and turnip mosaic virus.

Description

Technical Field

[0001] The invention belongs to the technical field of microbial pesticides, and particularly relates to application of Bacillus Velezii Bv-6 in preventing and controlling plant viruses. Background Art

[0002] Plant virus diseases have become the first major disease that endangers my country's agricultural production, seriously restricting the healthy and sustainable development of my country's agriculture. The outbreak of plant virus diseases is very widespread. There are more than 1,000 common plant virus diseases. Almost all vegetables, grain crops, fruit trees, etc. will be infected with virus diseases. The occurrence of plant virus diseases will reduce the quality of agricultural products and seriously promote the occurrence of other physiological diseases of plants (Yang Hongyuan et al., 2006). Among them, tobacco mosaic virus (TMV) is one of the most widely and deeply studied viruses. TMV has a wide range of hosts and can infect more than 310 species of plants in 30 families, including many important economic crops (Zhou Xiangping et al., 2024). Turnip mosaic virus (TuMV) belongs to the genus Potyirus and has a wide host range. It has become one of the most serious viruses that harm vegetables (Wang Fengting et al., 2023).

[0003] In field production, the prevention and control of plant virus diseases generally adopts measures such as pest control, strengthening field management, plant quarantine, isolation of infected plants, disease-resistant breeding, etc. to control the spread of viruses; or chemical agents are used for prevention and control, such as guanidine hydrochloride, copper sulfate, triazole compounds, etc. However, the current prevention and control of plant virus diseases is mainly reflected in the early prevention effect. Long-term single drug use will also lead to the development of virus resistance and cause pesticide residue problems (Xiao Peiying et al., 2005).

[0004] The use of microorganisms for biological control can not only play a good role in the prevention and control of plant viral diseases, but also reduce environmental pollution and is not easy to produce drug resistance. It has become a hot topic in the research of plant viral disease prevention and control at home and abroad (Li Xinglong et al., 2015). For example, Lin Zhixin et al. isolated a photosynthetic bacterium Rhodopseudomonas palustris from sewage sludge. The active substances in its fermentation liquid can induce broad beans and amaranth to produce resistance to cucumber mosaic virus (CMV) and carnation mottle virus (CaMV) (Lin Zhixin et al., 1992); Bi Jianhua et al. found that the fermentation liquid of Serratia marcescens 2A2 strain can significantly destroy the structure of TMV virus particles, inhibit the proliferation of TMV in the host, and induce the host to produce systemic resistance (Bi Jianhua et al., 2014). Zhang Chengsheng et al. studied the anti-TMV activity of the bacterial suspension of Bacillus subtilis Tpb55 strain and found that the bacterial suspension had a 96.15% inhibition rate on TMV (Zhang Chengsheng et al., 2019). Bacillus velezensis is a widely studied biocontrol bacterium. Currently, related reports mainly focus on promoting plant growth and preventing and controlling plant fungal and bacterial diseases. There are relatively few reports on the prevention and control of plant viral diseases by Bacillus velezensis. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a new option for biological control of plant viral diseases.

[0006] The technical scheme of the invention is application of Bacillus velezensis Bv-6 in preventing and controlling plant viruses, and the preservation number of Bacillus velezensis Bv-6 is CCTCC No: M20191106.

[0007] Specifically, the plant virus is one or more of tobacco mosaic virus or turnip mosaic virus.

[0008] Preferably, the host of the plant virus is a plant of the Solanaceae family.

[0009] Specifically, the Solanaceae plant is tobacco or tomato.

[0010] The invention also provides a biological preparation for preventing and controlling plant viruses, wherein the main component of the biological preparation is the fermentation liquid or wettable powder of Bacillus velezensis Bv-6; the preservation number of Bacillus velezensis Bv-6 is CCTCC No: M20191106.

[0011] Furthermore, the concentration of the wettable powder is 1×10 11 cfu / g.

[0012] The present invention also provides a method for improving the antiviral ability of plants, comprising the following steps: performing a passivation treatment or a preventive treatment on the plants by using Bacillus velezensis Bv-6; the preservation number of the Bacillus velezensis Bv-6 is CCTCC No: M20191106.

[0013] Particularly, the passivation treatment is: rubbing the plant with the fermentation liquid of Bacillus velezensis Bv-6 and the virus liquid for inoculation.

[0014] Wherein, the preventive treatment is: spraying plants with fermentation liquid of Bacillus velezensis Bv-6.

[0015] Furthermore, the Bacillus velezensis Bv-6 is prepared into a fermentation liquid or a wettable powder.

[0016] Specifically, the concentration of the wettable powder is 1×10 11 cfu / g.

[0017] Wherein, the virus is tobacco mosaic virus and / or turnip mosaic virus.

[0018] Preferably, the host of the virus is a plant of the Solanaceae family.

[0019] Specifically, the Solanaceae plant is tobacco or tomato.

[0020] The present invention also provides a method for preventing and controlling plant viruses, comprising the following steps: using Bacillus velezensis Bv-6 to irrigate roots and / or spray plants; the preservation number of the Bacillus velezensis Bv-6 is CCTCC No: M20191106.

[0021] Furthermore, the Bacillus velezensis Bv-6 is prepared into a fermentation liquid or a wettable powder.

[0022] Specifically, the concentration of the wettable powder is 1×10 11 cfu / g.

[0023] Specifically, the wettable powder was diluted 200 times.

[0024] Wherein, the plant virus is tobacco mosaic virus and / or turnip mosaic virus.

[0025] Preferably, the host of the plant virus is a plant of the Solanaceae family.

[0026] Specifically, the Solanaceae plant is tobacco or tomato.

[0027] Beneficial effects of the present invention: The present invention first discovered that the fermentation liquid of Bacillus velezensis Bv-6 and its wettable powder can effectively prevent and control tobacco mosaic virus and turnip mosaic virus. Among them, the preventive effect of tobacco plants treated with 200-fold dilution of Bv-6 fermentation liquid and its wettable powder on turnip mosaic virus was 48.33% and 40.32% respectively; the therapeutic effect was 16.96% and 15.11% respectively; the passivation effect was 99.90% and 100% respectively. The prevention effect of 200-fold dilution of Bv-6 wettable powder on tomato plants against tobacco mosaic virus was 9.54%, 66.66% and 76.19% respectively.

[0028] The Bacillus velezensis used in the present invention is specifically the Bacillus velezensis Bv-6 strain, which was deposited in the China Center for Type Culture Collection (address: Wuhan University, Wuhan, China) on December 25, 2019, with the collection number: CCTCC No: M20191106. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1The results of the inhibition of Turnip mosaic virus by the fermentation liquid of Bacillus Velez Bv-6 (3 dpi). Compared with the CK control, the fluorescence intensity of Turnip mosaic virus at the virus friction inoculation point of tobacco leaves was significantly weakened after 3 days of passivation treatment, prevention treatment and treatment with Bv-6 fermentation liquid. The inhibition rates of Bv-6 fermentation liquid on Turnip mosaic virus (3 dpi) were 98.58% (passivation treatment), 57.84% (prevention treatment) and 12.21% (treatment treatment), respectively.

[0030] Figure 2 The control effect of Bacillus Velez Bv-6 fermentation liquid on Turnip mosaic virus (7 dpi). Compared with the CK control, the systemic infection rate of Turnip mosaic virus on tobacco plants was significantly reduced after 7 days of passivation treatment, prevention treatment and treatment with Bv-6 fermentation liquid. The inhibition rates of Bv-6 fermentation liquid on Turnip mosaic virus (7 dpi) were 99.90% (passivation treatment), 48.33% (prevention treatment) and 16.96% (treatment treatment).

[0031] Figure 3 The results of the inhibition of Bacillus Velez Bv-6 wettable powder on Turnip mosaic virus (3 dpi). Compared with the CK control, the fluorescence intensity of Turnip mosaic virus at the virus friction inoculation point of tobacco leaves was significantly weakened after 3 days of passivation treatment, prevention treatment and treatment with Bv-6 wettable powder. The inhibition rates of Bv-6 wettable powder on Turnip mosaic virus (3 dpi) were 100.00% (passivation treatment), 54.32% (prevention treatment) and 5.80% (treatment treatment).

[0032] Figure 4 The control effect of Bacillus Velez Bv-6 wettable powder on Turnip mosaic virus (7 dpi). Compared with the CK control, the systemic infection rate of Turnip mosaic virus on tobacco plants was significantly reduced after 7 days of passivation, prevention and treatment with Bv-6 wettable powder. The inhibition rates of Bv-6 wettable powder on Turnip mosaic virus (7 dpi) were 100.00% (passivation treatment), 40.32% (prevention treatment) and 15.11% (treatment treatment).

[0033] Figure 5The control effect of Bacillus Velez Bv-6 wettable powder on tobacco mosaic virus (10 dpi). Compared with the CK control, the systemic infection rate of tobacco mosaic virus in tomato plants treated with 200-fold dilution of Bv-6 wettable powder by root irrigation, foliar spraying, root irrigation + foliar spraying was significantly reduced. The inhibition rates of Bv-6 wettable powder on tobacco mosaic virus (10 dpi) were 76.19% (root irrigation + foliar spraying), 66.66% (foliar spraying) and 9.54% (root irrigation).

[0034] Figure 6 The results of the inhibition of Turnip mosaic virus by fermentation broth of different Bacillus strains (3 dpi). The strains tested were Bacillus velezensis Bv-6, Bacillus velezensis Bv-10, Bacillus velezensis Bv-12, Bacillus subtilis Bs-1 and Bacillus paranthracis Bp1. The inhibition rates of spraying fermentation broth of each Bacillus on Turnip mosaic virus (3 dpi) were 99.60% (Bv-6), 57.02% (Bv-10), 65.51% (Bv-12), 71.00% (Bs-1) and 18.44% (Bp-1).

[0035] Figure 7 The control effect of fermented liquid of different Bacillus strains on Turnip mosaic virus (7 dpi). The strains tested were Bacillus velezensis Bv-6, Bacillus velezensis Bv-10, Bacillus velezensis Bv-12, Bacillus subtilis Bs-1 and Bacillus paranthracis Bp1. The control effect of spraying fermented liquid of each Bacillus on Turnip mosaic virus (7 dpi) was 99.93% (Bv-6), 41.10% (Bv-10), 57.62% (Bv-12), 55.15% (Bs-1) and 8.79% (Bp-1). DETAILED DESCRIPTION

[0036] Bacillus velezensis is a widely studied biocontrol bacterium. Current reports mainly focus on its growth promotion and resistance to fungal and bacterial diseases. Based on a new strain of Bacillus velezensis Bv-6 disclosed in the prior application, the applicant further studied its functions in various aspects. Therefore, relevant experiments were conducted from the perspective of biological control, and the results showed that the new strain had significant control effects on Turnip mosaic virus and Tobacco mosaic virus.

[0037] In order to better explain the present invention, the main contents of the present invention are further explained below in conjunction with specific examples, but the contents of the present invention are not limited to the following examples. The technical solutions involved in the embodiments of the present invention, if not otherwise specified, are all conventional solutions in the art; the reagents or materials, if not otherwise specified, are all derived from commercial channels.

[0038] The Bacillus velezensis described in the present invention is Bacillus velezensis Bv-6, with a deposit number of CCTCC No: M20191106, which has been disclosed in the patent document with application number 201911381534.2.

[0039] Fermentation broth preparation:

[0040] The Bv-6 strain stored in the laboratory was taken out from the -80°C refrigerator, and Bv-6 was streaked on the LB solid plate for activation. After culturing at 28°C for 24 h, a single colony of activated Bv-6 was picked and placed in a 250 mL conical flask containing 100 mL LB liquid medium with a pH of 7. The Bv-6 seed solution was obtained by shaking at 28°C and 180 rpm for 48 h. The seed solution was transferred to the 5% inoculum.

[0041] The culture was transferred into a 500 mL conical flask containing 250 mL of LB liquid medium with a pH of 7, and fermented in a shaking incubator at 28°C and 180 rpm for 48 h to obtain the Bv-6 shaking culture broth.

[0042] Preparation of LB liquid medium (1 L): Add 10 g tryptone, 5 g yeast extract, and 10 g sodium chloride to 950 mL ddH2O, adjust the pH to 7.0 with 1 mol / L NaOH, and make up to 1 L. Sterilize at 121°C and autoclave for 20 min, and store at 4°C.

[0043] Preparation of wettable powder:

[0044] 100 g of wettable starch was added to 1 L of the fermentation liquid of Bacillus Velez subtilis Bv-6 obtained above, and the mixture was stirred evenly. The mixture was spray-dried by a spray dryer to obtain a mother powder.

[0045] Spray drying indicators: inlet air temperature 180℃, outlet air temperature 65℃, pump speed about 3000 mL / h (real-time adjustment).

[0046] The collected mother powder was prepared according to the following formula ratio: 10 g mother powder, 5 g sodium butylnaphthalene sulfonate, 5 g calcium lignin sulfonate, and 80 g kaolin, and mixed well to obtain a wettable powder.

[0047] Dilute the above wettable powder sample with sterile water to 10 6 ~10 10 times, take 0.1 mL and evenly spread it on NA plate and culture at 28℃. After 48 h, observe and record the number of single colonies, repeat 3 times. The concentration of Bacillus Velezii Bv-6 wettable powder was 1×10 11 cfu / g, the wettable powder of the present invention or simply referred to as powder.

[0048] Example 1 Test on the efficacy of fermentation broth of Bacillus velez Bv-6 against Turnip mosaic virus

[0049] Take 0.1 g of GFP-tagged Turnip mosaic virus TuMV (NCBI accession number NC_002509) virus source and grind it thoroughly with 10 mL of 0.1 M PBS buffer to obtain TuMV virus inoculum for use. Detect the inactivation, prevention and treatment effects of Bacillus Velez Bv-6 fermentation broth on Turnip mosaic virus.

[0050] Passivation treatment: Bv-6 fermentation liquid and TuMV virus liquid were fully mixed in advance (20 min), and the control was mixed with the same volume of LB culture medium. After mixing, friction inoculation was performed on the same leaf position of a one-month-old Nicotiana benthamiana plant. The treatment and control were repeated for three tobacco plants each.

[0051] Preventive treatment: The leaves to be rubbed were evenly sprayed with LB culture medium and Bv-6 fermentation liquid respectively. After 24 hours, the TuMV virus liquid was frictionally inoculated on the same leaf position of a one-month-old Nicotiana benthamiana plant. The treatment and control were repeated for three tobacco plants each.

[0052] Treatment: First, friction inoculate the TuMV virus solution on the same leaf position of a one-month-old Nicotiana benthamiana plant. 24 hours after inoculation, evenly spray the friction leaves with LB culture medium and Bv-6 fermentation liquid, respectively. Repeat for three tobacco plants each for treatment and control.

[0053] Three days after the friction inoculation of TuMV virus, the inhibition rate of TuMV lesions on the friction leaves was counted, and the ultraviolet flashlight was placed at the same height (10 cm) above the friction inoculated leaves of N. benthamiana to take pictures, and then the GFP fluorescence brightness of the pictures was measured using Image J software. Seven days after the friction inoculation of TuMV virus, the TuMV system-infected leaves with GFP fluorescence were counted under the irradiation of the ultraviolet flashlight, and the TuMV system infection rate and control effect were calculated based on the proportion of TuMV system-infected leaves to the total leaves of tobacco plants.

[0054] Lesion inhibition rate (%) = (fluorescence intensity of control friction leaves - fluorescence intensity of treatment friction leaves) / fluorescence intensity of control friction leaves × 100%

[0055] System infection rate (%) = System infection leaf area / plant leaf total area × 100%

[0056] Control effect (%) = (system infection rate of control plants - system infection rate of treated plants) / system infection rate of control plants × 100%

[0057] The results are as follows Figure 1 , Figure 2 As shown in Table 1, 3 days after friction inoculation of Turnip mosaic virus, the lesion inhibition rates of Bv-6 fermentation broth for prevention, treatment and passivation were 57.84%, 12.21% and 98.58% respectively compared with the CK control; 7 days after friction inoculation of Turnip mosaic virus, the control effect was calculated by systemic infection rate. Compared with the CK control, the control effects of Bv-6 fermentation broth for prevention, treatment and passivation were 48.33%, 16.96% and 99.90% respectively.

[0058] Table 1. Control results of Bv-6 fermentation liquid against turnip mosaic virus (7 dpi)

[0059]

[0060] Example 2 Test on the efficacy of Bacillus Velezii Bv-6 wettable powder against Turnip mosaic virus

[0061] Take 0.1 g of TuMV virus source with GFP tag, grind it thoroughly with 10 mL 0.1 M PBS buffer to obtain TuMV virus inoculum, dilute Bv-6 wettable powder 200 times with sterile water and set aside. Detect the inactivation, prevention and treatment effects of 200-fold dilution of Bacillus Velezii Bv-6 wettable powder on Turnip mosaic virus.

[0062] Passivation treatment: 1×10 11 A 200-fold dilution of Bv-6 wettable powder (cfu / g) was thoroughly mixed with the TuMV virus solution (20 min), and the control was mixed with the same volume of sterile water. After mixing, the same leaf position of a one-month-old Nicotiana benthamiana plant was friction-inoculated, and the treatment and control were repeated for three tobacco plants each.

[0063] Preventive treatment: Spray the leaves to be rubbed evenly with sterile water and 200-fold diluted Bv-6 wettable powder, respectively. After 24 hours, rub the TuMV virus solution on the same leaf position of a one-month-old Nicotiana benthamiana plant. Repeat the treatment and control with three tobacco plants each.

[0064] Treatment: First, friction inoculate the TuMV virus solution on the same leaf position of a one-month-old Nicotiana benthamiana plant. 24 hours after inoculation, evenly spray the friction leaves with sterile water and 200-fold dilution of Bv-6 wettable powder, respectively. Repeat the treatment and control with three tobacco plants each.

[0065] Three days after the friction inoculation of TuMV virus, the TuMV lesion inhibition rate of the friction leaves was counted, and the ultraviolet flashlight was placed at the same height (10 cm) above the friction inoculated leaves of N. benthamiana to take pictures, and then the GFP fluorescence brightness of the pictures was measured using Image J software. Seven days after the friction inoculation of TuMV virus, under the irradiation of ultraviolet flashlight, the TuMV system-infected leaves with GFP fluorescence were counted, and the TuMV system infection rate was calculated based on the proportion of TuMV system-infected leaves to the total leaves of tobacco plants.

[0066] and calculation of control effects.

[0067] Lesion inhibition rate (%) = (fluorescence intensity of control friction leaves - fluorescence intensity of treated friction leaves) / fluorescence intensity of control friction leaves × 100%

[0068] System infection rate (%) = System infection leaf area / plant leaf total area × 100%

[0069] Control effect (%) = (systemic infection rate of control plants - systemic infection rate of treated plants) / systemic infection rate of control plants × 100%.

[0070] The results are as follows Figure 3 , Figure 4As shown in Table 2, 3 days after friction inoculation of Turnip mosaic virus, the lesion inhibition rates of 200-fold dilution of Bv-6 wettable powder on Turnip mosaic virus were 54.32%, 5.80% and 100.00% respectively compared with the CK control; 7 days after friction inoculation of Turnip mosaic virus, the control effect was calculated by systemic infection rate. Compared with the CK control, the control effects of 200-fold dilution of Bv-6 wettable powder on Turnip mosaic virus were 40.32%, 15.11% and 100.00% respectively.

[0071] Table 2. Control results of Bv-6 WP against Turnip Mosaic Virus (7 dpi)

[0072]

[0073] Example 3 Test on the efficacy of Bacillus Velezii Bv-6 wettable powder against tobacco mosaic virus

[0074] Take 0.1 g of tobacco mosaic virus TMV source, grind it thoroughly with 10 mL 0.1 M PBS buffer to obtain TMV virus inoculum, dilute Bv-6 wettable powder 200 times with sterile water and set aside. The control effect of 200-fold dilution of Bv-6 wettable powder on tobacco mosaic virus TMV was tested on tomato plants. The four treatments set in the experiment were:

[0075] (1) CK treatment: After each tomato plant was irrigated with 50 mL of sterile water, sterile water was sprayed on the front of the leaves until water dripped;

[0076] (2) Root irrigation with 200-fold dilution of Bv-6 powder: After irrigating the roots of each tomato plant with 50 mL of 200-fold dilution of Bv-6 powder, spray sterile water on the front of the leaves until water drops;

[0077] (3) Spraying treatment with 200-fold dilution of Bv-6 powder: After each tomato plant was irrigated with 50 mL of sterile water, 200-fold dilution of Bv-6 powder was sprayed on the front of the leaves until the drops fell;

[0078] (4) Treatment of root irrigation + spraying with 200-fold diluted Bv-6 powder: After each tomato plant was irrigated with 50 mL of 200-fold diluted Bv-6 powder, the front of the leaves was sprayed with 200-fold diluted CanL-30 powder until the drug drops fell.

[0079] After 24 hours of treatment, the TMV virus inoculum was taken and inoculated on the third branch leaves of the tomato plants by friction. Five tomato plants were repeated for each treatment. Ten days after friction inoculation, the TMV disease index was counted and the control effect was calculated.

[0080] Tomato TMV disease symptom grading standard: Level 0: no symptoms; Level 1: the veins of the heart leaves are clear, and 1-2 true leaves are mosaic; Level 3: the leaves in the middle and upper parts are mosaic; Level 5: most leaves are mosaic, and a few leaves are deformed; Level 7: most leaves are severely mosaic, deformed, and wrinkled; Level 9: almost all leaves are severely mosaic, deformed, and wrinkled, and the plant is obviously dwarfed.

[0081] Disease index = Σ (number of diseased plants at each level × corresponding level) / (total number of plants surveyed × highest representative value) × 100

[0082] Control effect (%) = (1-disease index of treatment group / disease index of control group) × 100%

[0083] The results are as follows Figure 5 As shown in Table 3, 10 days after friction inoculation of tobacco mosaic virus, the control effects of 200-fold dilution of Bv-6 wettable powder on tobacco mosaic virus by root irrigation, foliar spraying, and root irrigation + foliar spraying were 9.54%, 66.66%, and 76.19%, respectively, compared with the CK control.

[0084] Table 3. Control results of Bv-6 WP against tobacco mosaic virus (10 dpi)

[0085]

[0086] Example 4 Test on the protective effect of fermentation broth of different Bacillus strains against Turnip mosaic virus

[0087] Bacillus subtilis Bs1, Bacillus paranthracis Bp1, Bacillus velezensis strains Bv-10 and Bv-12, and Bacillus velezensis strain Bv-6 were used to compare the protective effects against Turnip mosaic virus. The LB shake culture fermentation broth of five Bacillus species, Bs1, Bp1, Bv-10, Bv-12 and Bv-6, was tested for its passivation activity against Turnip mosaic virus, and the control was treated with LB medium.

[0088] The LB shaking culture fermentation broth of Bs1, Bp1, Bv-10, Bv-12 and Bv-6 was fully mixed with the TuMV virus solution in advance (20 min), and the control was mixed with the same volume of LB culture medium. After mixing, the juice was rubbed and inoculated on the same leaf position of a one-month-old Nicotiana benthamiana plant. The control and each treatment were repeated for three tobacco plants.

[0089] Three days after the friction inoculation of TuMV virus, the inhibition rate of TuMV lesions on the friction leaves was counted, and the ultraviolet flashlight was placed at the same height (10 cm) above the friction inoculated leaves of N. benthamiana to take pictures, and then the GFP fluorescence brightness of the pictures was measured using Image J software. Seven days after the friction inoculation of TuMV virus, the TuMV system-infected leaves with GFP fluorescence were counted under the irradiation of the ultraviolet flashlight, and the TuMV system infection rate and control effect were calculated based on the proportion of TuMV system-infected leaves to the total leaves of tobacco plants.

[0090] Lesion inhibition rate (%) = (fluorescence intensity of control friction leaves - fluorescence intensity of treated friction leaves) / fluorescence intensity of control friction leaves × 100%

[0091] System infection rate (%) = System infection leaf area / plant leaf total area × 100%

[0092] Control effect (%) = (system infection rate of control plants - system infection rate of treated plants) / system infection rate of control plants × 100%

[0093] The results are as follows Figure 6 , Figure 7 As shown in Table 4, 3 days after friction inoculation with Turnip mosaic virus, the lesion inhibition rate of Bacillus Velez strain Bv-6 (99.60%) > Bacillus subtilis strain Bs-1 (71.00%) > Bacillus Velez strain Bv-12 (65.51%) > Bacillus Velez strain Bv-10 (57.02%) > Bacillus parathracis strain Bp1 (18.44%) compared with the CK control; 3 days after friction inoculation with Turnip mosaic virus, the lesion inhibition rate of Bacillus Velez strain Bv-6 (99.60%) > Bacillus subtilis strain Bs-1 (71.00%) > Bacillus Velez strain Bv-12 (65.51%) > Bacillus Velez strain Bv-10 (57.02%) > Bacillus parathracis strain Bp1 (18.44%) was higher than that of Bacillus parathracis strain Bp1 (18.44%). d later, the virus system infection rate CK (10.44%) > Bacillus paraanthrax strain Bp1 (9.39%) > Bacillus Velez strain Bv-10 (6.20%) > Bacillus subtilis strain Bs-1 (4.51%) > Bacillus Velez strain Bv-12 (4.28%) > Bacillus Velez strain Bv-6 (0.01%); 7 d after friction inoculation of Turnip mosaic virus, the control effect of each strain on Turnip mosaic virus after passivation was: Bacillus Velez strain Bv-6 (99.93%) > Bacillus Velez strain Bv-12 (57.62%) > Bacillus subtilis strain Bs-1 (55.15%) > Bacillus Velez strain Bv-10 (41.10%) > Bacillus paraanthrax strain Bp1 (8.79%).

[0094] Table 4. Control results of different strains against Turnip mosaic virus (7 dpi)

[0095]

Claims

1. Bacillus Velez Bacillus velezensis The application of Bv-6 in preventing and controlling plant viruses is characterized by: Bacillus Velez Bacillus velezensis The accession number of Bv-6 is CCTCC No:M20191106; The plant virus is Turnip mosaic virus; the host of the plant virus is tobacco.

2. A method for improving plant antiviral ability, characterized in that: The method comprises the following steps: using Bacillus Velez Bacillus velezensis Bv-6 is used to passivate or prevent plants; the Velez bacillus Bacillus velezensis The deposit number of Bv-6 is CCTCC No: M20191106; the plant virus is Turnip mosaic virus; and the host of the plant virus is tobacco.

3. The method according to claim 2, characterized in that: The passivation treatment is: using Bacillus Velezii Bacillus velezensis Bv-6 fermentation liquid and virus liquid rubbed plant inoculation; or, the preventive treatment is: using Bacillus Velez Bacillus velezensis Bv-6 fermentation liquid is sprayed on plants.

4. A method for preventing and controlling plant viruses, characterized in that: The method comprises the following steps: using Bacillus Velez Bacillus velezensis Bv-6 root irrigation and / or spraying plants; the Velez Bacillus Bacillus velezensis The accession number of Bv-6 is CCTCC No:M20191106; The virus is turnip mosaic virus; the host of the virus is tobacco; the Velez bacillus Bacillus velezensis Bv-6 is made into fermentation liquid or wettable powder, and the wettable powder is diluted 200 times.

5. The method according to claim 4, characterized in that: The concentration of the wettable powder is 1×10 11 cfu / g.

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