Bacillus siamensis and application thereof

Abstract

The invention relates to the technical field of biological control, and discloses bacillus siamensis and application thereof. The bacillus siamensis disclosed by the invention is preserved in the China General Microbiological Culture Collection Center (CGMCC), and the preservation number is CGMCC NO.32576. The bacillus siamensis has a good control effect on pepper phytophthora blight, the field control effect can reach 71.69 + / -8.00%, meanwhile, the bacillus siamensis can antagonize various plant pathogenic fungi in a broad spectrum, and the bacillus siamensis can be used for preventing and treating various plant diseases.

Description

Technical Field

[0001] The invention belongs to the field of biological control, and specifically relates to siam bacillus and application thereof. Background Art

[0002] Pepper (Capsicum annuum L.) is one of the largest vegetable industries in my country. During production, pepper is harmed by a variety of diseases, among which pepper blight is the most serious. Pepper blight is a typical soil-borne disease caused by Phytophthora capsici. It can infect pepper roots, stems, leaves, and fruits at both the seedling and adult stages, causing symptoms such as root rot, stem rot, and sudden wilting. Because pepper blight has a wide host range, spreads quickly, and has a variety of transmission methods, it is very difficult to prevent and control pepper blight.

[0003] In terms of the prevention and control of pepper blight, chemical control has become the most widely used control method because chemical agents are low in price, highly effective, and are not limited by time, space, soil type, and environmental conditions. Commonly used agents on the market include dimethomorph, azoxystrobin, flumorph, fosetyl-aluminum, chlorothalonil, mancozeb, metalaxyl, and metalaxyl-M, but the mechanism of action of these agents is to target a single link in the metabolism of pathogens. Once the action site mutates, the pathogens will develop drug resistance, thereby reducing the control effect. In addition, the use of a large number of chemical pesticides will lead to a series of problems such as excessive pesticide residues, destruction of soil microbial balance, and environmental pollution.

[0004] Biological control is a method of using biocontrol bacteria or their metabolites to control the occurrence, reproduction or reduce the harm of pest populations. The mechanism of action of biocontrol bacteria mainly includes competition, antibacterial effect, inducing plant systemic resistance and promoting plant growth. Therefore, biological control has the advantages of safety, effectiveness, no residue, environmental protection and sustainability, and is an effective measure to ensure the sustainable development of agriculture and food production. At present, there are many research reports on the application of pepper blight control bacteria to control pepper blight. Wang Rongbo et al. (2022) screened Bacillus subtilis BS193 by plate confrontation method, and the inhibition rate of pepper blight was 66.70%. Both in vitro leaf and indoor pot tests showed good control effect. In addition, the bacteria showed a good growth-promoting effect on pepper plants, with plant height, root length, fresh weight and dry weight increased by 48.16-73.27%, respectively. Zou Xiuwei (2022) and others screened Bacillus Velezii Y4-39 using the plate confrontation method, which mainly exerts antibacterial activity by producing antimicrobial peptides. Pot experiments showed that its fermentation liquid had a 67.78% prevention effect on pepper phytophthora, and has the potential to develop biological fertilizer.

[0005] Screening and obtaining highly effective pepper blight control bacteria is an important strain resource and prerequisite for the development of microbial fungicides. By the end of April 2024, there were only two microbial pesticides effectively registered in my country for the prevention and treatment of pepper blight (500 million CFU / ml Brevibacillus laterosporus A60 suspension and 10 billion CFU / ml Bacillus subtilis suspension). Therefore, the current number and effect of pepper blight control bacteria are far from meeting the production needs of research and development of microbial agents. Summary of the invention

[0006] In view of this, the present invention provides a biocontrol bacterium Bacillus siamensis SD23LJ1314 for preventing and controlling pepper blight, which provides high-quality strain resources for green prevention and control of pepper blight and research and development of microbial agents.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The invention provides a Siamese bacillus, which is BacillussiamensisSD23LJ1314 and has a preservation number of CGMCC NO.32576.

[0009] In the present invention, the 16S rDNA gene sequence of the siam bacillus is shown as SEQ ID NO: 1, and the gyrB gene sequence is shown as SEQ ID NO: 2.

[0010] In the present invention, the single colony formed by the reproduction and growth of the Siamese Bacillus on the LB medium has irregular edges, is milky white, has wrinkles on the surface of the colony, is rod-shaped under microscopic examination, has flagella, is Gram-positive, and produces spores.

[0011] The present invention also includes a culture of the above-mentioned Siamese Bacillus, which is obtained by culturing the above-mentioned Siamese Bacillus in a microbial culture medium.

[0012] As an embodiment, the microbial culture medium is LB solid culture medium or LB liquid culture medium.

[0013] As an embodiment, the culture includes a bacterial suspension, a fermentation broth and / or a metabolite thereof of Bacillus siamese.

[0014] Another object of the present invention is to provide the use of the above-mentioned Bacillus siamensis and / or its culture in any of the following:

[0015] 1) inhibiting plant pathogens; the plant pathogens are at least one of the following: Phytophthora capsici, Fusarium oxysporum, Fusarium graminearum, Fusarium pseudograminearum, Fusarium pseudoverticillium, Fusarium laminarum, Fusarium fusogenum, Fusarium fusogenum, Colletotrichum siamese, Colletotrichum capsici, Botrytis cinerea and Alternaria solani;

[0016] 2) preparing the inhibitor of plant pathogenic bacteria described in 1);

[0017] 3) preventing and controlling plant diseases caused by the plant pathogens mentioned in 1);

[0018] 4) preparing the inhibitor of plant diseases described in 3).

[0019] As an embodiment, the Fusarium oxysporum includes the watermelon-specific type of Fusarium oxysporum, the tomato-specific type of Fusarium oxysporum, the cotton-specific type of Fusarium oxysporum, the bitter melon-specific type of Fusarium oxysporum, the melon-specific type of Fusarium oxysporum, the bean-specific type of Fusarium oxysporum, the strawberry-specific type of Fusarium oxysporum and the cabbage-specific type of Fusarium oxysporum.

[0020] As an embodiment, the plant diseases include pepper blight, crop wilt, wheat fusarium wilt, wheat stem base rot, corn ear rot, corn stalk rot, rice seedling blight, strawberry root rot, strawberry anthracnose, pepper anthracnose, pepper gray mold and pepper early blight.

[0021] As an embodiment, the method for controlling plant diseases with Siamese Bacillus comprises: soaking the roots of plants with Siamese Bacillus or its culture before transplanting, and irrigating the roots with Siamese Bacillus or its culture after transplanting.

[0022] The present invention also provides a microbial agent containing the above-mentioned Siamese Bacillus and / or culture.

[0023] Compared with the prior art, the present invention has the following advantages and effects:

[0024] The Siamese Bacillus of the present invention has a good prevention effect on pepper blight, and the field prevention effect can reach 71.69±8.00%, which is better than the existing registered microbial pesticides for preventing and controlling pepper blight and is equivalent to the prevention effect of chemical pesticides. The Siamese Bacillus of the present invention has a broad spectrum of antagonistic effects on plant pathogenic fungi and can be used for the prevention and control of various plant diseases.

[0025] Collection Instructions

[0026] Bacillus siamensis SD23LJ1314 was deposited in the General Microbiology Center of China Microorganism Culture Collection Administration on November 11, 2024, with the deposit number CGMCC NO.32576; address: Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the phylogenetic tree of strain SD23LJ1314 obtained based on the gyrB gene sequence. DETAILED DESCRIPTION

[0028] The invention separates and purifies a strain of Bacillus siamensis SD23LJ1314 from rhizosphere soil of robust pepper plants. The strain has high prevention effect on pepper phytophthora and a wide prevention spectrum.

[0029] At present, the siamese Bacillus SD23LJ1314 has been deposited in the General Microbiology Center of the China Microorganism Culture Collection Administration, with the deposit number: CGMCC NO.32576; address: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences; deposit date: November 11, 2024, classified as Bacillus siamensis.

[0030] The single colony formed by the siam bacillus propagating and growing on the LB culture medium has irregular edges, is milky white, has wrinkles on the colony surface, is rod-shaped under microscopic examination, has flagella, is Gram-positive, and produces spores.

[0031] The 16S rDNA gene sequence of the siam bacillus of the present invention is shown in SEQ ID NO: 1. The 16S rDNA is compared with NCBI blast, and the result shows that the homology similarity with Bacillus is greater than 99%, indicating that the SD23LJ1314 strain is of the genus Bacillus. The gyrB gene sequence of the siam bacillus of the present invention is shown in SEQ ID NO: 2. A phylogenetic tree is constructed based on the gyrB gene sequence and the gyrB gene sequence of the model strain with high homology to the sequence of the strain to be tested downloaded from NCBI, and the SD23LJ1314 strain is identified as Bacillus siamensis.

[0032] The present invention also includes the culture of the above-mentioned Siamese Bacillus, which refers to the substance obtained by culturing Siamese Bacillus in a microbial culture medium, including but not limited to the bacterial suspension, fermentation broth and / or its metabolites of Siamese Bacillus. The microbial culture medium here refers to a culture medium that can achieve the growth and expansion of Siamese Bacillus, including but not limited to LB solid culture medium or LB liquid culture medium, and an improved culture medium on LB culture medium to achieve better growth or metabolism of Siamese Bacillus. Those skilled in the art can adjust or improve the culture medium and culture conditions according to the actual culture situation. As an embodiment, the culture method of Siamese Bacillus includes inoculating Siamese Bacillus in LB liquid culture medium, shaking and culturing at 150-180rpm and 30-35℃ for 10-12h, and then transferring to LB liquid culture medium at a ratio of 1-2%, shaking and culturing at 150-180rpm and 30-35℃ for 48h, and obtaining Siamese Bacillus fermentation broth. The content of Siamese Bacillus in the Siamese Bacillus fermentation broth is 1×109 -2×10 9 cfu / mL.

[0033] The siam bacillus and the culture thereof have the function of inhibiting various plant pathogens and can be used as the sole or partial active ingredient of the plant pathogen inhibitor. Preferably, the siam bacillus and its culture of the present invention are effective against Phytophthora capsici, Fusarium oxysporum f.sp. niveum, F.oxysporum f.sp. lycopersici, F.oxysporum f.sp. vasinfectum, F.oxysporum f.sp. momordicae, F.oxysporum f.sp. melonis, F.oxysporum f.sp. phaseoli, F.oxysporum f.sp. fragariae, F.oxysporum f.sp. cabbage, and F.oxysporum It has inhibitory effects on many plant pathogenic fungi, including F.sp.conglutinans, F.graminearum, F.pseudograminearum, F.sporotrichioides, F.proliferatum, F.fujikuroi, Pestalotiopsis, Colletotrichum sisamense, C.capsici, Botrytis cinerea, and Alternaria solani.

[0034] The Siamese Bacillus and its culture of the present invention achieve the effect of preventing and controlling plant diseases by inhibiting plant pathogens, and can be used as the sole or partial active ingredient of plant disease inhibitors. As an embodiment, the plant diseases of the present invention include pepper blight caused by Phytophthora capsici, crop wilt caused by various specialized types of Fusarium oxysporum, wheat head blight caused by Fusarium graminearum, wheat stem base rot caused by Pseudomonas graminearum, corn ear rot caused by Pseudomonas verticillata, corn stem rot caused by Fusarium laminarum, rice seedling blight caused by Fusarium fusarifolium, strawberry root rot caused by Pseudomonas spp., strawberry anthracnose caused by Siamese anthracnose, pepper anthracnose caused by Colletotrichum capsici, pepper gray mold caused by Botrytis cinerea, and pepper early blight caused by Alternaria solanacea. As an optional embodiment, before transplanting pepper seedlings, the seedlings are root-soaked in the original solution of Siamese Bacillus fermentation liquid, and after the peppers are planted, the roots are irrigated with a bacterial suspension of Siamese Bacillus or a diluted solution of the fermentation liquid. Experiments have shown that the Siamese bacillus of the present invention can have a good control effect on pepper blight, and the field control effect reaches 71.69±8.00%.

[0035] The present invention also provides a microbial agent, comprising the siam bacillus and / or its culture of the present invention. The microbial agent of the present invention can be produced according to methods well known to those skilled in the art. The preparation type of the microbial agent can be in the form of a solution, a dispersant, a suspension, a powder, etc. The use method can be spraying, broadcasting, furrow application or irrigation with water.

[0036] In one embodiment, the microbial agent of the present invention further comprises a microorganism type different from the siam Bacillus of the present invention, and the different microorganisms are used in combination to expand the host spectrum of the microbial agent, improve the control effect on plant pathogens, and delay the development of drug resistance.

[0037] In one embodiment, the siam bacillus or its culture of the present invention can be freeze-dried or dissolved in a suitable solvent to prepare a microbial agent. Freeze-drying is performed using conventional methods in the art. The solvent can be water, microbial culture medium, etc.

[0038] The present invention is further described below in conjunction with specific examples, but the present invention is not limited to the following examples. The plant pathogens used in the following examples are derived from plant pathogenic bacteria species preserved in the laboratory and are known types of plant pathogens. The experimental methods used in the examples are conventional methods unless otherwise specified, and the materials, reagents, etc. used can be obtained from commercial sources unless otherwise specified.

[0039] Example 1

[0040] Screening of Antagonistic Bacteria against Phytophthora capsici

[0041] Select healthy pepper plants, collect their rhizosphere soil, dry in the shade, mix well, take 1g and add it to a triangular flask containing 100mL sterile water and sterilized glass beads, place the triangular flask in a 30℃ shaker, shake at 180rpm for 30min, and then stand at room temperature for 30min. Take 1mL of supernatant and add it to 9mL sterile water for serial dilution, take 100μL of dilution to spread on LB solid medium, stand at 30℃ for 24h, and select different types of colonies for purification and culture.

[0042] Take pepper phytophthora as the target bacteria, inoculate in the middle of the PDA plate, inoculate the test bacteria 2cm away from the pathogen, and inoculate 3 test bacteria per plate. Take the plate inoculated with pepper phytophthora only as the blank control to indicate the growth of pepper phytophthora. Culture at 25℃, when pepper phytophthora on the blank control plate grows all over the culture plate, measure the control growth of pepper phytophthora (colony radius d1), treatment growth (inhibition growth radius d2 after inoculation of bacteria) and the growth edge of pepper phytophthora to the growth edge of the test bacteria d3 (i.e., the inhibition zone), calculate the inhibition rate, and screen the strains with antagonistic effects.

[0043] Antibacterial rate (%) = (d1-d2) / d1×100.

[0044] From 11458 pepper rhizosphere and endophytic bacteria, 190 strains antagonistic to pepper Phytophthora were obtained by plate confrontation.

[0045] Example 2

[0046] Screening of highly effective strains against Phytophthora capsici

[0047] Preparation of antagonistic bacteria fermentation broth: The antagonistic bacteria of Example 1 were inoculated in a test tube containing 5 mL of LB liquid culture medium, and cultured at 180 rpm and 30°C for 12 h, then transferred to 200 mL of LB liquid culture medium at a ratio of 1%, and cultured at 180 rpm and 30°C for 48 h to obtain antagonistic bacteria fermentation broth. The content of antagonistic bacteria in the antagonistic bacteria fermentation broth was 1×10 9 -2×10 9 cfu / mL.

[0048] Pepper seeds were sown in a plug tray filled with vermiculite for seedling cultivation. When the peppers emerged and grew to 4 leaves and 1 heart, they were transplanted into a pot filled with nutrient soil. When the pepper seedlings grew to about 20 cm in height and had about 15 leaves, they were inoculated with pathogens and watered with antagonistic bacteria fermentation liquid. The operation was as follows: the seedlings were watered with 40 mL of 10-fold diluted antagonistic bacteria fermentation liquid one day before inoculation of pathogens, and the seedlings were inoculated with a suspension of Phytophthora spores (concentration of 5×10 4Each seedling was inoculated with 3 mL of the antagonistic bacteria fermentation solution and watered again after 3-5 days. Three replicates were set for each treatment, with 45 seedlings in each replicate, and the control effect was investigated after 15 days.

[0049] Disease investigation standards:

[0050] Dead seedlings: There are spots at the base of the stem, the lower leaves fall off, the upper part of the plant loses water and wilts, and the whole plant dies.

[0051] Health: No symptoms.

[0052] Seedling death rate (%) = (number of dead seedlings / total number of trees surveyed) × 100

[0053] Control effect (%) = [(control seedling death rate - treatment seedling death rate) / control seedling death rate] × 100

[0054] Under greenhouse conditions, pot experiments were used to conduct primary and secondary screening of antagonistic strains against pepper blight. From 190 antagonistic bacteria, the strain SD23LJ1314 with the best control effect on pepper blight was obtained, with a control efficiency of 78.53%.

[0055] Table 2 Indoor bioassay evaluation of the efficacy of biocontrol bacteria SD23LJ1314 against pepper blight

[0056]

[0057]

[0058] Example 3

[0059] Identification of the taxonomic status of strain SD23LJ1314

[0060] The genome of strain SD23LJ1314 was extracted by the improved CTAB method. Primers of 16s rDNA and gyrB gene sequences were used to amplify SD23LJ1314 DNA, and the PCR products were detected by 1% agarose gel electrophoresis. The products were sequenced by Shanghai Sangon Biotechnology Co., Ltd. The sequencing results were subjected to homology analysis and multiple sequence alignment in the GenBank database of NCBI, and a phylogenetic tree was constructed based on the alignment results using MEGA software.

[0061] The universal primers for 16S rDNA sequences are:

[0062] 27F: 5'-AGAGTTTGATCCTGGCTCAG-3',

[0063] 1492R: 5'-CTACGGCTACCTTGTTACGA-3'.

[0064] PCR reaction system: 10×Easy Tap Mix 25μL, 27-F 1μL, 1492-R 1μL, DNA 1μL, ddH2O22μL.

[0065] PCR amplification program: 94°C for 5 min, 94°C for 45 s, 58°C for 45 s, 72°C for 1 min, 35 cycles, 72°C for 10 min, 4°C∞.

[0066] The universal primers for the gyrB gene are:

[0067] gyrB-F: 5'-TTGRCGGHRGYGGHTATAAAGT-3',

[0068] gyrB-R: 5'-TCCDCCSTCAGARTCWCCCTC-3'.

[0069] PCR reaction system: 10×Easy Tap Mix 25μL, gyrB-F 1μL, gyrB-R 1μL, DNA 1μL, ddH2O22μL.

[0070] PCR amplification program: 94°C for 5 min, 95°C for 30 s, 58°C for 45 s, 72°C for 1 min, 35 cycles, 72°C for 5 min, 4°C∞.

[0071] The 16S rDNA universal primers 27F / 1492R were used to amplify the SD23LJ1314 strain, and the size was 1445bp. After NCBI blast comparison, the results showed that its homology with Bacillus was greater than 99%, and the SD23LJ1314 strain belonged to the genus Bacillus. The universal primers gyrB-F and gyrB-R were used for PCR amplification, and the size was 1000bp. The gyrB gene sequence of the model strain with high homology to the strain sequence was downloaded from NCBI, and the phylogenetic tree was constructed. The SD23LJ1314 strain was identified as Bacillus siamese ( Figure 1 ).

[0072] Example 4

[0073] Field evaluation of SD23LJ1314 strain

[0074] Field evaluation was conducted on the biocontrol bacteria SD24LJXF1314. The field evaluation was completed in the diseased nursery using the microbial agent Bacillus subtilis 10 billion CFU / ml suspension and the chemical pesticides formazan and cymoxanil as controls.

[0075] The preparation method of SD23LJ1314 fermentation broth was the same as that in Example 2. The bacterial content of SD23LJ1314 in the fermentation broth was 1×109 cfu / mL. The experiment set up four treatments: root irrigation with biocontrol bacteria SD23LJ1314, root irrigation with commercial bacterial agents, root irrigation with chemical agents and blank control, with three replicates for each treatment and random distribution of plots.

[0076] Before transplanting pepper seedlings, the seedlings were soaked in the original solution of SD23LJ1314 fermentation liquid for 30 minutes. After planting, the first application of 1-fold dilution of SD23LJ1314 fermentation liquid was applied to the roots (100 mL / tree) on the same day. The second irrigation (100 mL / tree) was carried out 3-5 days after planting, and the third irrigation was carried out 7 days later. This was used three times in succession. The root irrigation treatment was treated with a five-fold dilution of Bacillus subtilis 10 billion CFU / ml suspension as a biocontrol bacteria control, and the root irrigation treatment was treated with a 2000-fold dilution of 25% carbendazim·cymoxanil wettable powder as a chemical control. The treatment method was the same as SD23LJ1314. Each treatment was repeated 3 times, with 60 trees in each repeat, and a disease survey was conducted 15 days later.

[0077] Disease investigation standards:

[0078] Dead seedlings: There are spots at the base of the stem, the lower leaves fall off, the upper part of the plant loses water and wilts, and the whole plant dies.

[0079] Health: No symptoms.

[0080] Seedling death rate (%) = (number of dead seedlings / total number of trees surveyed) × 100

[0081] Control effect (%) = [(control seedling death rate - treatment seedling death rate) / control seedling death rate] × 100

[0082] The results showed that the field control effect of SD24LJXF1314 was 71.69%; the field control effects of Bacillus subtilis 10 billion CFU / ml suspension and chemical pesticides formazan and cymoxanil were 49.05% and 77.36%, respectively (Table 3).

[0083] Table 3 Field trials evaluating the efficacy of biocontrol bacteria against pepper blight

[0084]

[0085]

[0086] Example 5

[0087] Determination of the antibacterial spectrum of SD23LJ1314 strain

[0088] The plate confrontation method was used to determine the antibacterial spectrum of the biocontrol strain SD23LJ1314.

[0089] The specific method is: use a hole puncher (Φ=6mm) to punch holes on the edge of the newly activated pathogen colony to make a bacterial cake, transfer it to the center of a new PDA plate, and then inoculate the newly activated SD23LJ1314 strain 2cm to the left and right of the bacterial cake. The plate inoculated with only pathogens is used as a blank control to indicate the growth of pathogens. Culture at a constant temperature of 25℃, and when the blank control is about to grow all over the culture dish, measure the control growth of pathogens (colony radius d1), treatment growth (inhibition growth radius d2 after inoculation of bacteria) and the distance d3 from the growth edge of pathogens to the growth edge of the bacteria to be tested (i.e., the inhibition zone), and calculate the inhibition rate.

[0090] Antibacterial rate (%) = (d1-d2) / d1×100.

[0091] The results showed that the biocontrol strain SD23LJ1314 had an effective effect on Fusarium oxysporum

[0092] (Fusarium oxysporum f.sp.niveum), Fusarium oxysporum f.sp.lycopersici), Fusarium oxysporum f.sp.vasinfectum, Fusarium oxysporum f.sp.mospermum, Fusarium oxysporum f.sp.

[0093] momordicae), Fusarium oxysporum f.sp.melonis, Fusarium oxysporum f.sp.phaseoli, Fusarium oxysporum f.sp.fragariae, Fusarium oxysporum f.sp.conglutinans, Fusarium graminearum, Fusarium pseudograminearum, Fusarium pseudoverticillioides, Fusarium oxysporum f.sp.

[0094] sporotrichioides, F.proliferatum, F.fujikuroi, Pestalotiopsis, Colletotrichumsisamense, C.capsici, Botrytis cinerea and Alternaria solani all showed good antibacterial ability, with the inhibition rate ranging from 61.19% to 81.73%.

[0095] Table 4 Inhibitory effect of biocontrol bacteria SD23LJ1314 on different pathogens

[0096]

[0097]

[0098] The above embodiments are the best implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A siam bacillus, characterized in that The Siamese Bacillus is Bacillus siamensisSD23LJ1314, and its deposit number is CGMCC NO.32576.

2. The siam bacillus according to claim 1, characterized in that The 16S rDNA gene sequence of the siam bacillus is shown in SEQ ID NO: 1, and the gyrB gene sequence is shown in SEQ ID NO:

2.

3. The culture of Bacillus siamensis according to claim 1 or 2, characterized in that The culture is obtained by culturing the siam Bacillus according to any one of claims 1 to 2 in a microbial culture medium.

4. The culture according to claim 3, characterized in that The microbial culture medium is LB solid culture medium or LB liquid culture medium.

5. The culture according to claim 3, characterized in that The culture comprises a bacterial suspension, a fermentation liquid and / or a metabolite thereof of Bacillus siamese.

6. Use of the siam bacillus according to claim 1 or 2 and / or the culture according to any one of claims 3 to 5 in any of the following: 1) inhibiting plant pathogens; the plant pathogens are at least one of the following: Phytophthora capsici, Fusarium oxysporum, Fusarium graminearum, Fusarium pseudograminearum, Fusarium pseudoverticillium, Fusarium laminarum, Fusarium fusogenum, Fusarium fusogenum, Colletotrichum siamese, Colletotrichum capsici, Botrytis cinerea and Alternaria solani; 2) preparing the inhibitor of plant pathogenic bacteria described in 1); 3) preventing and controlling plant diseases caused by the plant pathogens mentioned in 1); 4) preparing the inhibitor of plant diseases described in 3).

7. The use according to claim 6, characterized in that: The Fusarium oxysporum includes Fusarium oxysporum watermelon-specific type, Fusarium oxysporum tomato-specific type, Fusarium oxysporum cotton-specific type, Fusarium oxysporum bitter melon-specific type, Fusarium oxysporum melon-specific type, Fusarium oxysporum bean-specific type, Fusarium oxysporum strawberry-specific type and Fusarium oxysporum cabbage-specific type.

8. The use according to claim 6, characterized in that: The plant diseases include pepper blight, crop wilt, wheat head blight, wheat stem base rot, corn ear rot, corn stalk rot, rice seedling blight, strawberry root rot, strawberry anthracnose, pepper anthracnose, pepper gray mold and pepper early blight.

9. The use according to claim 6, characterized in that: The method for preventing and controlling plant diseases with Siamese bacillus comprises the following steps: soaking the roots of plants with Siamese bacillus or its culture before transplanting, and irrigating the roots with Siamese bacillus or its culture after transplanting.

10. A microbial agent, characterized in that: Containing the siam bacillus according to any one of claims 1 to 2, and / or the culture according to any one of claims 3 to 5.

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