Bacillus velezensis BR-1 and application thereof in prevention and treatment of economic crop diseases

Abstract

The invention discloses bacillus velezensis BR-1 and application of the bacillus velezensis BR-1 in prevention and treatment of economic crop diseases. The preservation number of the bacillus velezensis BR-1 is CCTCC NO: M 20251379. The bacillus velezensis BR-1 disclosed by the invention is high in adaptability and wide in growth condition range, and is more beneficial to application in agricultural production. Meanwhile, the bacillus velezensis BR-1 has a remarkable inhibition effect on the growth of various phytopathogens such as verticillium dahliae, fusarium oxysporum, sclerotinia sclerotiorum and ralstonia solanacearum, can remarkably reduce the morbidity of cotton verticillium wilt, fusarium wilt and tomato bacterial wilt under a greenhouse condition, and has a wide agricultural application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of biological pesticides, in particular to Bacillus velezensis BR-1 and its application in the prevention and treatment of diseases of economic crops. BACKGROUND

[0002] Cotton, rapeseed and tomato are important economic crops in the world, and play an important role in agricultural production. However, these crops are often harmed by some plant pathogens, causing huge economic losses, such as cotton verticillium wilt, cotton fusarium wilt, rapeseed sclerotinia rot, tomato bacterial wilt and so on.

[0003] In cotton, cotton verticillium wilt and cotton fusarium wilt are two main diseases in cotton production, both of which are soil-borne vascular diseases, and show symptoms of leaf yellowing, wilting, shedding and even early decline of the plant after the disease occurs. 1. Cotton verticillium wilt: caused by Verticillium dahliae, the pathogen can survive in soil for a long time, the pathogen invades the stem of the plant through the root system, and finally leads to significant reduction in yield and quality, which is the most common and serious disease in global cotton production. Verticillium dahliae

[0004] 2. Cotton fusarium wilt: caused by Fusarium oxysporum, often causes plant wilting and death at seedling stage or early growth stage, and is less harmful than cotton verticillium wilt in general. Fusarium oxysporum

[0005] Rapeseed sclerotinia rot and rapeseed alternaria blight are two important fungal diseases of rapeseed: 1. Rapeseed sclerotinia rot (caused by Sclerotinia sclerotiorum) is one of the most harmful diseases in rapeseed production. The pathogen can infect stems, leaves and silique, causing large area of plant lodging and significant yield reduction. Sclerotinia sclerotiorum can produce persistent sclerotia, which exist in soil for a long time, making it extremely difficult to control. Sclerotinia sclerotiorum 2. Rapeseed alternaria blight (caused by Alternaria alternata) is an important leaf disease of rapeseed, which often causes black-brown necrotic spots on leaves, and can cause early leaf senescence, affecting photosynthetic efficiency and kernel fullness when severe.

[0006] Alternaria brassicae Tomato bacterial wilt is caused by Ralstonia solanacearum, which is a devastating soil-borne bacterial disease. The pathogen can invade through root wounds or natural openings, rapidly spread to the vascular bundle, causing plant wilting and death. This disease not only occurs universally in tomato producing areas, but also can infect more than 50 families and 250 species of plants.

[0007] Tomato bacterial wilt is caused by Ralstonia solanacearum, which is a devastating soil-borne bacterial disease. The pathogen can invade through root wounds or natural openings, rapidly spread to the vascular bundle, causing plant wilting and death. This disease not only occurs universally in tomato producing areas, but also can infect more than 50 families and 250 species of plants. Ralstonia solanacearum

[0008] ​​​​Cotton Verticillium wilt, Fusarium wilt, Sclerotinia sclerotiorum and Alternaria brassicae of oilseed rape and tomato bacterial wilt and other such diseases of economic crops have strong soil-borne, strong variability of pathogenic bacteria, long incubation period, wide host range, and are difficult to control, which have caused serious threat to crop production. At present, the control measures for these diseases mainly include disease-resistant variety breeding, crop rotation, soil disinfection and chemical pesticide control. However, these measures have different degrees of limitations: the resistance of disease-resistant varieties is easy to lose and the breeding cycle is long; crop rotation is limited by labor and land resources in large-scale application; soil disinfection technology is complex, high in cost and unstable in effect; and long-term application of chemical pesticides will cause environmental pollution and increase of pathogenic bacteria resistance. In recent years, biological control as a green and sustainable control approach has gradually attracted attention. The use of antagonistic microorganisms to inhibit or compete with pathogenic bacteria can not only effectively reduce the incidence of diseases, but also be conducive to ecological environment protection. In the research of cotton Verticillium wilt, Fusarium wilt, Sclerotinia sclerotiorum of oilseed rape, Alternaria brassicae of oilseed rape and tomato bacterial wilt, many types of antagonistic microorganisms such as Bacillus, Pseudomonas and Streptomyces have shown good application potential. Among them, Bacillus has the advantages of strong environmental adaptability, easy preservation and preparation due to the formation of spores resistant to adversity, and is the focus of current research and application.

[0009] However, the existing antagonistic strains still have deficiencies in adaptability, inhibition spectrum and field application stability, and are difficult to meet the stable control needs in complex farmland environment. Therefore, it is urgent to screen and develop new antagonistic strains with stronger environmental adaptability, wider inhibition spectrum and better control effect, to provide a new technical approach for the green control of important plant diseases such as cotton Verticillium wilt and Fusarium wilt, Sclerotinia sclerotiorum and Alternaria brassicae of oilseed rape, and tomato bacterial wilt. SUMMARY

[0010] The purpose of the present application is to overcome the deficiencies of the prior art, and provide a Bacillus velezensis BR-1 and its application in the control of diseases of economic crops. The Bacillus velezensis BR-1 of the present application has strong adaptability, a wide range of growth conditions (including temperature, pH value, etc.), and is more conducive to application in agricultural production. At the same time, the Bacillus velezensis BR-1 has a significant inhibitory effect on the growth of many plant pathogenic bacteria such as Lecanicillium giganteum, Fusarium oxysporum, Sclerotinia sclerotiorum and Ralstonia solanacearum, and can significantly reduce the incidence of cotton Verticillium wilt and tomato bacterial wilt under greenhouse conditions, and has a wide agricultural application prospect.

[0011] To achieve the above-mentioned purpose, the technical scheme designed by the present application is as follows: The present application provides a Bacillus velezensis (Bacillus velezensis) BR-1, whose preservation number is CCTCC NO: M 20251379. Bacillus velezensis )BR-1, whose preservation number is CCTCC NO: M 20251379.

[0012] The strain has been preserved in China Center for Type Culture Collection (CCTCC, Wuhan University, Wuhan, China, Postcode: 430072) on June 16, 2025, and the preservation number is CCTCC NO: M 20251379.

[0013] The application also provides application of the above-mentioned Bacillus velezensis BR-1 in resisting plant pathogenic fungi.

[0014] Further, the plant pathogenic fungi are any one of Plasmodiophora brassicae (P. Verticillium dahliae ), Fusarium oxysporum (P. Fusarium Oxysporum ), Alternaria brassicae (P. Alternaria brassicae ), Sclerotinia sclerotiorum (P. Sclerotinia sclerotiorum ) and Ralstonia solanacearum (P. Ralstonia solanacearum ). Alternaria brassicae ) and Ralstonia solanacearum (P.

[0015] Further, the plant pathogenic fungi are any one of Plasmodiophora brassicae (P. Verticillium dahliae ) and Ralstonia solanacearum (P. Ralstonia solanacearum ).

[0016] The application also provides application of the above-mentioned Bacillus velezensis BR-1 in preparing a biocontrol agent for preventing and treating diseases of economic crops.

[0017] Further, the diseases of economic crops are cotton verticillium wilt, cotton fusarium wilt, brassica sclerotinia disease, brassica alternaria disease and tomato bacterial wilt.

[0018] The Bacillus velezensis BR-1 can inhibit the growth of Plasmodiophora brassicae (P. Verticillium dahliae ), Fusarium oxysporum (P. Fusarium Oxysporum ), Alternaria brassicae (P. Alternaria brassicae ), Sclerotinia sclerotiorum (P. Sclerotinia sclerotiorum ) and Ralstonia solanacearum (P. Ralstonia solanacearum ), and reduce the activity of each pathogenic fungus.

[0019] The Bacillus velezensis BR-1 can inhibit the activity of Plasmodiophora brassicae (P. Verticillium dahliae ) and Ralstonia solanacearum (P. Ralstonia solanacearum ), and effectively reduce the incidence of cotton verticillium wilt or tomato bacterial wilt.

[0020] The application also provides a biocontrol agent for preventing and treating cotton verticillium wilt and tomato bacterial wilt, wherein the biocontrol agent contains the Bacillus velezensis BR-1.

[0021] Further, in the biocontrol agent, the concentration of the Bacillus velezensis BR-1 is 1x10 8~9 CFU / mL.

[0022] Further, in the biocontrol preparation, the concentration of Bacillus velezensis BR-1 is 1×10 8~9 CFU / mL.

[0023] The application further provides a preparation method of the biocontrol preparation, which comprises the following steps: firstly, picking a single colony of Bacillus velezensis BR-1 into a test tube containing 2 mL of NA culture medium, and culturing at 180 rpm / min and 28 DEG C overnight; secondly, taking 1 mL of the culture solution into a conical flask containing 100 mL of NA culture medium, and culturing at 180 rpm / min and 28 DEG C for 48 h; and thirdly, adjusting the cell concentration to 1×10 8~9 CFU / mL.

[0024] The application further provides application of the biocontrol preparation in prevention and treatment of diseases of economic crops.

[0025] Further, the diseases of economic crops are cotton verticillium wilt, cotton fusarium wilt, brassica black spot, brassica sclerotinia disease and tomato bacterial wilt.

[0026] The Bacillus velezensis BR-1 provided by the application is a plant endophyte strain, has strong plant tissue colonization ability, can stably survive in a plant body and continuously play an antagonistic role. Compared with the existing common prevention and treatment measures, the strain has the following beneficial effects: 1. The prevention and treatment effect is remarkable: the strain BR-1 shows good prevention and treatment effect on cotton verticillium wilt (the pathogenic bacteria are verticillium dahliae klebahn), especially in the mode of spraying treatment, which can effectively reduce the incidence of cotton verticillium wilt. The strain BR-1 shows excellent prevention and treatment effect on tomato bacterial wilt (the pathogenic bacteria are ralstonia solanacearum), and the prevention and treatment effect is equivalent to that of the commonly used chemical agent proleukin, which can effectively reduce the incidence of tomato bacterial wilt.

[0027] 2. Wide application range: in addition to being effective on tomato bacterial wilt and cotton verticillium wilt, the strain BR-1 cotton fusarium wilt (the pathogenic bacteria are fusarium oxysporum), brassica black spot and brassica sclerotinia disease all show obvious inhibitory activity, and have broad-spectrum antagonistic properties.

[0028] 3. Strong environmental adaptability: the strain BR-1 has strong adaptability to growth environment conditions (including temperature, pH, etc.), is convenient to popularize and apply in different ecological environments, and overcomes the problem of insufficient stability of some existing biocontrol strains in the application process.

[0029] 4. Safe and environmentally friendly: as a biological control strain, the strain BR-1 avoids the environmental pollution and pathogenic bacteria resistance problems caused by chemical pesticides, and meets the development direction of green agriculture.

[0030] In conclusion, the bacillus velezensis BR-1 has excellent application prospects in the prevention and treatment of tomato bacterial wilt, cotton yellow wilt and wilt, and oilseed rape black spot and oilseed rape sclerotinia disease, and various plant diseases, and has significant economic value and popularization value. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 Figure 1 is a colony morphology diagram of bacillus velezensis BR-1 after 48h culture.

[0032] Figure 2 Figure 4 is a schematic diagram of PCR amplification of the 16S rRNA sequence of the strain BR-1.

[0033] Figure 3 Figure 5 is a phylogenetic tree of the strain BR-1 based on 16S rRNA.

[0034] Figure 4 Figure 6 is the bacteriostatic effect of the strain BR-1 on plamopora delavayi; In the figure, the plamopora delavayi treatment is the bacteriostatic effect of the strain BR-1 on plamopora delavayi, and the plamopora delavayi control is the bacteriostatic effect of sterile water on plamopora delavayi.

[0035] Figure 5 Figure 7 is the bacteriostatic effect of the strain BR-1 on cotton fusarium wilt, oilseed rape sclerotinia, and alternaria alternata of oilseed rape; In the figure, A represents the bacteriostatic effect of the strain BR-1 on fusarium oxysporum; B represents the bacteriostatic effect of sterile water on fusarium oxysporum; C represents the bacteriostatic effect of the strain BR-1 on sclerotinia sclerotiorum; D represents the bacteriostatic effect of sterile water on sclerotinia sclerotiorum; E represents the bacteriostatic effect of the strain BR-1 on alternaria alternata; F represents the bacteriostatic effect of sterile water on alternaria alternata; Figure 6 Figure 8 is the inhibition effect diagram of the strain BR-1 on ralstonia solanacearum; In the figure, the ralstonia solanacearum treatment is the bacteriostatic effect of the strain BR-1 on ralstonia solanacearum, and the ralstonia solanacearum control is the bacteriostatic effect of sterile water on ralstonia solanacearum.

[0036] Figure 7 Figure 9 is a greenhouse control effect diagram of the strain BR-1 on plamopora delavayi; In the figure, A represents the effect diagram of BR-1 spraying treatment + plamopora delavayi, B represents the effect diagram of BR-1 root irrigation treatment + plamopora delavayi, C represents the effect diagram of sterile water control (blank control), D represents the effect diagram of carbendazim root irrigation treatment + L. laxus, E represents the effect diagram of sterile water root irrigation treatment + L. laxus.

[0037] Figure 8 Figure (10th day after inoculation) of the greenhouse control effect of strain BR-1 on R. solanacearum; The figures respectively represent: A represents BR-1 (concentration 1 x 10 8 CFU / mL) + R. solanacearum strain effect diagram, B represents BR-1 (concentration 1 x 10 9 CFU / mL) + R. solanacearum effect diagram, C represents the effect diagram of sterile water + R. solanacearum, D represents the effect diagram of kasugamycin + R. solanacearum (pesticide control), E represents the effect diagram of strain BR-1 alone root irrigation treatment, F represents the effect diagram of sterile water root irrigation treatment (blank control). DETAILED DESCRIPTION

[0038] The present application will be further described in conjunction with specific embodiments so as to be understood by those skilled in the art.

[0039] Example 1 Isolation, purification and identification of Bacillus velezensis BR-1 1. Isolation and purification of Bacillus velezensis BR-1 a. The healthy cotton tissues collected from the field were surface sterilized according to the following procedure: 70% (v / v) alcohol sterilization for 1 min, then 5% (v / v) sodium hypochlorite sterilization for 5 min, 70% (v / v) alcohol sterilization for 30 s, and finally rinsed with sterile water for 5 times, 1 min each time.

[0040] b. The sterilized tissues were dried with sterile dry filter paper to remove surface moisture, placed in a sterile mortar, and 1 mL of sterile distilled water was added to grind them into a homogenate. The supernatant homogenate was evenly coated on NA medium with a coating rod, and incubated in a 28°C constant temperature incubator. The colonies that grew were observed, c. Different morphological colonies were picked and plated for purification, and the purified colonies were picked into single colonies on NB medium and shaken for 48 h.

[0041] The above NA medium formula is as follows: bacterial protein peptone 5 g, beef extract 3 g, sodium chloride 5 g, distilled water to 1000 mL, 121°C sterilization for 30 min. Solid medium needs to add 12 g of agar powder.

[0042] Colony morphology as shown in Fig. 1: strain BR-1 was proved to be gram-positive bacteria by gram staining, and the colony morphology of strain BR-1 on NA medium was round or oval, the color was opaque ivory, the single colony was large, the colony surface was wrinkled, and the center was convex. Figure 1

[0043] 2. Identification of the strain The bacterial liquid of strain BR-1 was streaked on NA medium, and the colony morphology was observed after 24h culture. Molecular identification was carried out by 16S rRNA gene sequence analysis. The genomic DNA of the strain was extracted, and 16S rRNA universal primers 27F and 1492R were used, as follows: 27F: 5'-AGAGTTTGATCCTGGCTCAG-3', 1492R: 5'-GGTTACCTTGTTACGACTT-3'; PCR amplification was carried out.

[0044] The PCR reaction program was 95℃ pre-denaturation for 3min; 94℃ denaturation for 30s, 50℃ annealing for 1min, 72℃ extension for 1min, repeated for 35 cycles, and finally extended at 72℃ for 10min. The PCR product was sent to Shanghai Sangon Biotech Co., Ltd. for sequencing, and sequence homology comparison was completed by NCBI Blastn. The PCR amplification schematic diagram of the 16S rRNA sequence of strain BR-1 is shown in Fig. 2. Figure 2 .

[0045] After the PCR product of the 16S rRNA sequence of strain BR-1 was purified and recovered, 20ul of the purified product was sent to Shanghai Sangon Biotech Co., Ltd. for sequencing. The sequencing result showed that the length of the 16S rRNA sequence of the strain BR-1 described in the application was 1438bp, and the specific sequence was shown as SEQ ID NO: 1: ​ Sequence homology comparison results showed that it was related to Bacillus ( Bacillus The 16S rRNA gene sequence of the strain BR-1 showed 99.9% homology, indicating that the strain belonged to the genus Bacillus.

[0046] 3. Construction of a phylogenetic tree based on 16S rRNA The 16S rRNA sequences predicted by the gene were compared with the NCBI 16S rRNA sequence database using Blast, with the parameter identify>95. Then, the top 30 16S rRNA sequences with the highest identify were selected (all were selected if there were fewer), and multiple sequence alignment and pruning were performed using maft software. Finally, a phylogenetic tree was constructed using FastTree / iqtree / raxml software.

[0047] Phylogenetic tree such as Figure 3 As shown: strain BR-1 and Bacillus belesiensis ( Bacillus velezensis The closest genetic distance between BR-1 and Bacillus belesii indicates that BR-1 is a direct descendant of Bacillus belesii. Bacillus velezensis ). The above-screened strain was named *Bacillus belyssae* after morphological and 16S RNA gene sequence analysis. Bacillus velezensis BR-1. This strain was deposited on June 16, 2025, at the China Center for Type Culture Collection (CCTCC, Wuhan University, Wuhan, China 430072, China), with accession number CCTCC NO: M 20251379.

[0048] Example 2 Antibacterial test of Bacillus belyssus BR-1 1. Antibacterial test of Bacillus belye BR-1 against Ralstonia solanacearum The antibacterial activity of strain BR-1 against *Ralstonia solanacearum* was determined using the plate well diffusion method, as detailed below: After activation on NA plates, single colonies of strain BR-1 were picked and inoculated into NA liquid medium and cultured at 180 r / min and 28℃ for 24 h. The concentrations of the Ralstonia solanacearum and strain BR-1 bacterial suspensions were adjusted to 1×10⁻⁶. 8 CFU / mL. Ralstonia solanacearum bacterial suspension and NA medium (cooled to approximately 60°C) were mixed at a ratio of 1:100 (V:V) and poured into 90 mm diameter Petri dishes. After the medium solidified, two holes were punched 20 mm from the center using a 6 mm diameter punch. The medium was removed from the holes, and 5 µL of BR-1 bacterial suspension was added to each hole. 5 µL of sterile water was used as a control. Each treatment was repeated three times. After incubation at 28°C for 24 h, the diameter of the inhibition zone was measured.

[0049] As shown in Figure 4 : Strain BR-1 has significant antibacterial effect on Ralstonia solanacearum, and the inhibition zone diameter is 18.4±2.5 mm.

[0050] 2. Inhibition test of Bacillus velezensis BR-1 on Plasmodiophora brassicae The inhibition activity of strain BR-1 on Plasmodiophora brassicae was determined by plate confrontation method, as follows: After strain BR-1 was activated by NA plate, single colony was inoculated in NA liquid medium and cultured at 180 r / min and 28℃ for 24 h. The concentration of strain BR-1 was adjusted to 1×10 8 CFU / mL. The mycelial block of Plasmodiophora brassicae was inoculated in a 90 mm diameter culture dish, and then cultured in a 25℃ incubator for 2d. 5 μL of BR-1 bacterial liquid was added at 4 points 15 mm away from the edge of the colony, and 5 μL of sterile water was added as control. Each treatment was repeated 3 times. They were placed in a 25℃ incubator. After 5d, the diameter of the inhibition zone was measured.

[0051] As shown in Figure 5 : Strain BR-1 has significant antibacterial effect on Plasmodiophora brassicae, and the inhibition rate is 36.6%.

[0052] Table 1 Inhibition of strain BR-1 on Plasmodiophora brassicae 3. Inhibition test of Bacillus velezensis BR-1 on other plant pathogenic fungi The inhibition activity of strain BR-1 on Fusarium oxysporum, Alternaria brassicae and Sclerotinia sclerotiorum was determined by plate confrontation method, as follows: After strain BR-1 was activated by NA plate, single colony was inoculated in NA liquid medium and cultured at 180 r / min and 28℃ for 24 h. The concentration of strain BR-1 was adjusted to 1×10 8 CFU / mL. The mycelial block of Fusarium oxysporum, Alternaria brassicae and Sclerotinia sclerotiorum was inoculated in a 90 mm diameter culture dish, and then streaked with strain BR-1 liquid on both sides of the mycelial block, and streaked with sterile water as control. Each treatment was repeated 3 times. They were placed in a 25℃ incubator. After 7d, the colony diameter of treatment and control was measured, and the inhibition rate was calculated.

[0053] As shown in Figure 6 : Strain BR-1 has significant antibacterial effect on Fusarium oxysporum, Alternaria brassicae and Sclerotinia sclerotiorum, and the inhibition rates are 56.2%, 69.0% and 74.3%, respectively.

[0054] Table 2 Inhibition of different plant pathogenic fungi by strain BR-1 Example 3 A biocontrol preparation includes Bacillus velezensis BR-1, wherein the concentration of Bacillus velezensis BR-1 is 1 x 10 8 CFU / mL.

[0055] Example 4 Test of biocontrol preparation for inhibiting cotton Verticillium wilt 1. Material preparation a. Adjust the concentration of L. cylindracea spore solution to 5 x 10 6 spores / mL for standby.

[0056] b. Sow the seeds of cotton variety Jimian 11 into plastic pots with nutrient medium, prepare 30-35 cotton seedlings for each treatment, and wait until the cotton seedlings grow to 4-5 leaf ages for standby.

[0057] 2. Treatment method First, treat the cotton seedlings with strain BR-1 by root irrigation or spraying, with an average of 3 mL per cotton seedling or 1 mL per cotton seedling, and use 3 mL per cotton seedling of sterile water and 3 mL per cotton seedling of carbendazim (concentration of 0.1%) as controls. After 3 days, gently pull out the cotton seedlings from the medium, treat the roots with L. cylindracea spore solution for 5 minutes, and then transplant them into the nutrient medium in a 25-28°C greenhouse, with sterile water as a control. 20 days after inoculation with L. cylindracea, count the number of diseased plants and disease levels of different treatments, calculate the disease index and control effect, and repeat the test 3 times. Different treatments and controls include BR-1 spraying + L. cylindracea, BR-1 root irrigation + L. cylindracea, carbendazim + L. cylindracea, sterile water + L. cylindracea, and sterile water.

[0058] Table 3 Greenhouse control effect of strain BR-1 on L. cylindracea (20 days after inoculation) As shown in Tables 3 and Figure 7 : 20 days after inoculation with L. cylindracea, the control effect of strain BR-1 spraying treatment on L. cylindracea was 62.9%, the control effect of strain BR-1 root irrigation treatment on L. cylindracea was 40.6%, and the control effect of carbendazim on L. cylindracea was 22.3%. It is shown that the control effect of strain BR-1 on L. cylindracea is better than that of carbendazim, and thus the biocontrol preparation can inhibit cotton Verticillium wilt caused by L. cylindracea.

[0059] Example 5 Greenhouse test of biocontrol preparation for inhibiting tomato bacterial wilt 1. Material preparation a. Adjust the concentration of R. solanacearum bacterial solution to 1 x 108 CFU / mL, standby.

[0060] b. Tomato variety used is Dahong tomato 903, 2 tomato seedlings per pot, 15 pots per treatment, when the tomato seedlings grow to 5-6 leaf age, standby.

[0061] 2. Treatment method First, the above biocontrol agent two concentrations (1×10 8 CFU / mL and 1×10 9 CFU / mL) were used to irrigate the tomato seedlings, 10 mL per pot, 3 days later, Ralstonia solanacearum bacterial liquid was used to irrigate the treatment, 10 mL per pot, sterile water + Ralstonia solanacearum bacterial liquid irrigation, spring thunder + Ralstonia solanacearum bacterial liquid irrigation, strain BR-1 alone irrigation treatment and sterile water irrigation as control, the plants after inoculation were placed in a 28~30℃ greenhouse, 10 days after inoculation of Ralstonia solanacearum, the number of diseased plants and disease index of tomato plants in different treatments were counted, and the incidence, disease index and control effect were calculated.

[0062] As shown in Figure 8 : 10 days after inoculation of Ralstonia solanacearum, the control effect of strain BR-1 (concentration of 1×10 8 CFU / mL) on tomato bacterial wilt reached 72.6%, which was equivalent to the control effect of spring thunder (73.0%).

[0063] Table 4 Greenhouse control effect of strain BR-1 on tomato Ralstonia solanacearum (10 days after inoculation) The other parts not specifically described are prior art. Although the above examples make a detailed description of the present application, it is only a part of the embodiments of the present application, not all the embodiments, and other embodiments can be obtained according to the present embodiments without creativity, which all belong to the protection scope of the present application.

Claims

1. A type of Bacillus belesii ( Bacillus velezensis BR-1, its accession number is: CCTCC NO: M20251379.

2. The application of Bacillus brevis BR-1 as described in claim 1 in the treatment of plant pathogens.

3. The application according to claim 2, characterized in that: The plant pathogen is Verticillium dahliae ( ) Verticillium dahliae Fusarium oxysporum ( Fusarium Oxysporum ), Sclerotium sclerotiorum ( Sclerotinia sclerotiorum Alternaria alternata, the fungus causing black spot disease in rapeseed ( Alternaria brassicae ) and Ralstonia solanacearum ( Ralstonia solanacearum Any one of them.

4. The use of Bacillus berleis BR-1 as described in claim 1 in the preparation of biocontrol agents for the prevention and control of diseases of economic crops.

5. The application according to claim 1, characterized in that: The diseases of the economic crops mentioned are cotton Verticillium wilt, cotton Fusarium wilt, rapeseed sclerotinia stem rot, rapeseed black spot, and tomato bacterial wilt.

6. A biocontrol agent for controlling diseases of economic crops, characterized in that: The biocontrol agent contains Bacillus berleis BR-1.

7. The biocontrol agent according to claim 6, characterized in that: The biocontrol agent contains Bacillus belyceta BR-1 at a concentration of 1×10⁻⁶. 8~9 CFU / mL.

8. The biocontrol agent according to claim 6 or 7, characterized in that: The biocontrol agent contains Bacillus belyceta BR-1 at a concentration of 1×10⁻⁶. 8 CFU / mL.

9. A method for preparing the biocontrol agent according to claim 6, characterized in that: The method begins by picking a single colony of Bacillus belye BR-1 into a test tube containing NA medium and culturing it overnight. Then, 1 mL of the culture is inoculated into an Erlenmeyer flask containing 100 mL of NA medium and cultured for 48 hours. The cell concentration is then adjusted to 1 × 10⁻⁶ cells using a hemocytometer. 8~9 CFU / mL.

10. The application of the biocontrol agent according to claim 6 in the control of diseases of economic crops.

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