Bacillus siamensis snpv-z6 and microbial agent as well as preparation method and application of bacillus siamensis snpv-z6 and microbial agent

Abstract

The invention belongs to the technical field of fermentation, and particularly relates to bacillus siamensis snpz-z6, a microbial agent and a preparation method and application of the bacillus siamensis snpz-z6 and the microbial agent. The invention provides a strain of bacillus siamensis snpv-z6, the Latin name of the bacillus siamensis snpv-z6 is bacillus siamensis snpv-z6, the bacillus siamensis snpv-z6 is preserved in the China General Microbiological Culture Collection Center, the address is No.3, No.1 yard, Beichen West Road, Chaoyang District, Beijing, the preservation date is September 12, 2024, and the preservation number is CGMCC No.31958. The bacillus siamensis snpv-z6 can be used for preparing the bacillus siamensis. The bacillus siamensis snpv-z6 and the microbial agent prepared by using the bacillus siamensis snpv-z6 not only can inhibit the growth of various plant pathogenic fungi, but also can promote the growth and development of rice.

Description

Technical Field

[0001] The invention belongs to the technical field of fermentation, and specifically relates to a siam bacillus SNPV-Z6 and a microbial agent, and a preparation method and application thereof. Background Art

[0002] Plants are the main source of human food. However, fungi, bacteria and other microbial pathogens seriously endanger agricultural production. These harmful organisms directly cause production reduction. At present, chemical pesticides are mainly used to control them. However, chemical pesticides not only affect crops and the ecological environment, but also have serious problems of drug resistance. In this case, green pesticides represented by biopesticides have become an important alternative to agricultural fungicides. Studies have shown that antagonistic microorganisms naturally present in the environment can reduce plant fungal diseases by directly killing fungi or inducing plant resistance. They are highly efficient and economical, non-toxic and non-resistant, environmentally friendly and safe.

[0003] For example, rice is one of the most important food crops in the world and the crop with the largest planting area in the world. The occurrence of rice diseases seriously affects its yield and quality. Rice sheath blight is one of the most serious diseases that cause rice production reduction. The sexual state of the pathogenic bacteria of rice sheath blight is Thanatephorus cucumeris (Frank) Domk, which belongs to the genus Thanatephorus in the subdivision Basidiomycetes. The asexual state is Rhizoctonia solani Kühn, which belongs to the genus Rhizoctonia in the subdivision Ascomycetes. Under natural conditions, only the asexual state is available. During the growth and development of rice, especially when the temperature is high and the humidity is high and the rice is closed in rows, it is very easy to induce a large-scale outbreak of rice sheath blight with symptoms of cloud-like lesions. Due to the lack of highly resistant varieties, the method of controlling rice sheath blight is still to use chemical pesticides. Although chemical pesticides have many advantages, their widespread use will lead to drug resistance and pesticide residues, posing a serious threat to food safety, environmental hygiene and human health.

[0004] Therefore, screening, developing and utilizing antagonistic microorganisms to control plant diseases and gradually replace chemical pesticides have broad development prospects. Summary of the invention

[0005] In view of this, in order to solve the problems raised in the above background technology, the purpose of the present invention is to provide a strain of Bacillus siamese SNPV-Z6 and a microbial agent and a preparation method and application thereof.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a strain of Bacillus siamensis SNPV-Z6, the Latin name of the Bacillus siamensis SNPV-Z6 is Bacillus siamensis SNPV-Z6, which is deposited in the General Microbiology Center of China Microorganism Culture Collection Administration, with the address of No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, the deposit date is September 12, 2024, and the deposit number is CGMCC No.31958.

[0008] The present invention also provides the use of the Siamese Bacillus SNPV-Z6 in preparing products for inhibiting fungal activity and promoting plant growth.

[0009] Preferably, the fungi include one or more of rice sheath blight, corn sheath blight, tobacco target spot pathogen, tobacco brown spot pathogen, rapeseed sclerotinia, potato late blight, tomato early blight pathogen, graminearum Fusarium, rice seedling pathogen, tomato gray leaf spot pathogen, rubber tree anthracnose, camellia anthracnose, tea oil anthracnose, tobacco black shank pathogen, pepper anthracnose, verticillium fusarium, apple ring rot pathogen, tobacco root rot pathogen, sweet potato root rot pathogen, melon wilt pathogen, wheat root rot pathogen, corn leaf blight pathogen, corn Curvularia leaf spot pathogen and celery leaf blight pathogen.

[0010] The present invention also provides a microbial agent, comprising a fermentation liquid or a sterile fermentation liquid obtained by fermenting the siam bacillus SNPV-Z6.

[0011] Preferably, the method for preparing the fermentation broth comprises the following steps:

[0012] (1) activating Bacillus siamese SNPV-Z6 at 35-39° C. for 10-14 hours to obtain an activated bacterial solution;

[0013] (2) Inoculate the activated bacterial solution into a liquid culture medium and culture at 35-39° C. for 20-28 h to obtain a fermentation solution.

[0014] Preferably, the method for preparing the aseptic fermentation broth comprises the following steps:

[0015] 1) activating Bacillus siamese SNPV-Z6 at 35-39° C. for 10-14 hours to obtain an activated bacterial solution;

[0016] 2) inoculating the activated bacterial solution into a liquid culture medium, culturing at 35-39° C. for 20-28 hours to obtain a fermentation liquid;

[0017] 3) Centrifuge the fermentation broth and take the supernatant; filter the supernatant and take the filtrate to obtain the sterile fermentation broth.

[0018] Preferably, in step 3), the centrifugal temperature is 2-6°C; the centrifugal speed is 8000-12000 rpm; and the centrifugal time is 15-25 min.

[0019] Preferably, in step 3), the filtration is membrane filtration; the pore size of the membrane is 0.20-0.24 μm.

[0020] The present invention also provides the use of the microbial agent in preparing products for inhibiting fungal activity and promoting plant growth.

[0021] Preferably, the fungi include one or more of rice sheath blight, corn sheath blight, tobacco target spot pathogen, tobacco brown spot pathogen, rapeseed sclerotinia, potato late blight, tomato early blight pathogen, graminearum Fusarium, rice seedling pathogen, tomato gray leaf spot pathogen, rubber tree anthracnose, camellia anthracnose, tea oil anthracnose, tobacco black shank pathogen, pepper anthracnose, verticillium fusarium, apple ring rot pathogen, tobacco root rot pathogen, sweet potato root rot pathogen, melon wilt pathogen, wheat root rot pathogen, corn leaf blight pathogen, corn Curvularia leaf spot pathogen and celery leaf blight pathogen.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention screens out a strain of Bacillus siamensis snpv-z6, the strain and the fermentation liquid or aseptic fermentation liquid obtained by fermenting the strain can significantly inhibit the growth of Rhizoctonia solani, the pathogen of rice sheath blight, and has a significant inhibitory effect on a variety of plant pathogenic fungi; the strain has simple culture conditions, is easy to preserve and industrially produce, and can be used as an ideal biocontrol agent;

[0024] The microbial agent prepared by using the strain and the fermentation liquid or aseptic fermentation liquid obtained by fermenting the strain can not only inhibit the growth of various plant pathogenic fungi, but also promote the growth and development of rice; the microbial agent can reduce pollution to agriculture and effectively improve the soil environment, thereby minimizing the harm to the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the morphological identification result of strain snpv-z6;

[0026] Figure 2 This is the result of oil microscope examination of strain snpv-z6;

[0027] Figure 3 is the phylogenetic tree;

[0028] Figure 4The inhibitory effect of Bacillus siameensis snpv-z6 on Rhizoctonia solani, the left picture is the control group, and the right picture is the treatment group;

[0029] Figure 5 The inhibitory effect of Bacillus siamese SNPV-Z6 on the growth of various fungi;

[0030] Figure 6 The inhibitory effect of the aseptic fermentation liquid on Rhizoctonia solani, where the left picture is the control group and the right picture is the treatment group;

[0031] Figure 7 The control effect of microbial agents on rice sheath blight, where A is the blank control group, B is the positive control group, C is treatment group 1, and D is treatment group 2;

[0032] Figure 8 This is a diagram showing the effect of microbial agents on promoting rice growth, where A is the control group and B is the treatment group.

[0033] Collection Instructions

[0034] A strain of Bacillus siamensis SNPV-Z6, the Latin name of the Bacillus siamensis SNPV-Z6 is Bacillussiamensis SNPV-Z6, which is deposited in the General Microbiology Center of China Microorganism Culture Collection Administration, the address of which is No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, the deposit date is September 12, 2024, and the deposit number is CGMCC No.31958. DETAILED DESCRIPTION

[0035] The present invention provides a strain of Bacillus siamensis SNPV-Z6, the Latin name of the Bacillus siamensis SNPV-Z6 is Bacillus siamensis SNPV-Z6, which is deposited in the General Microbiology Center of China Microorganism Culture Collection Administration, with the address of No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, the deposit date is September 12, 2024, and the deposit number is CGMCC No.31958.

[0036] The present invention also provides the use of the Siamese Bacillus SNPV-Z6 in preparing products for inhibiting fungal activity and promoting plant growth.

[0037] In the present invention, the fungi include one or more of rice sheath blight, corn sheath blight, tobacco target spot, tobacco brown spot, rape sclerotinia, potato late blight, tomato early blight, graminearum Fusarium, rice seedling pathogen, tomato gray leaf spot, rubber tree anthracnose, camellia anthracnose, tea oil anthracnose, tobacco black shank pathogen, pepper anthracnose, Fusarium verticillioides, apple ring spot, tobacco root rot, sweet potato root rot, melon wilt, wheat root rot, corn leaf spot, corn Curvularia leaf spot and celery leaf spot;

[0038] The plant is rice.

[0039] The present invention also provides a microbial agent, comprising a fermentation liquid or a sterile fermentation liquid obtained by fermenting the siam bacillus SNPV-Z6.

[0040] In the present invention, the method for preparing the fermentation broth comprises the following steps:

[0041] (1) activating Bacillus siamese SNPV-Z6 at 35-39° C. for 10-14 hours to obtain an activated bacterial solution;

[0042] (2) Inoculate the activated bacterial solution into a liquid culture medium and culture at 35-39° C. for 20-28 h to obtain a fermentation solution.

[0043] In the present invention, in step (1), the activation temperature is preferably 37° C.; the activation time is preferably 12 h; the activation speed is 150 to 210 rpm, preferably 180 rpm;

[0044] The activated culture medium is a liquid LB culture medium; the liquid LB culture medium uses water as a solvent and includes 1% tryptone, 0.5% yeast extract, and 0.5% NaCl;

[0045] In step (2), the liquid culture medium is liquid LB culture medium;

[0046] The culture temperature is preferably 37° C.; the culture time is preferably 24 h; and the culture rotation speed is 150 to 210 rpm, preferably 180 rpm.

[0047] In the present invention, the method for preparing the aseptic fermentation broth comprises the following steps:

[0048] 1) activating Bacillus siamese SNPV-Z6 at 35-39° C. for 10-14 hours to obtain an activated bacterial solution;

[0049] 2) inoculating the activated bacterial solution into a liquid culture medium, culturing at 35-39° C. for 20-28 hours to obtain a fermentation liquid;

[0050] 3) Centrifuge the fermentation broth and take the supernatant; filter the supernatant and take the filtrate to obtain the sterile fermentation broth.

[0051] In the present invention, in step 1), the activation temperature is preferably 37°C; the activation time is preferably 12h; the activation speed is 150-210rpm, preferably 180rpm;

[0052] The activated culture medium is a liquid LB culture medium; the liquid LB culture medium uses water as a solvent and includes 1% tryptone, 0.5% yeast extract, and 0.5% NaCl;

[0053] In step 2), the liquid culture medium is liquid LB culture medium;

[0054] The culture temperature is preferably 37°C; the culture time is preferably 24 hours; the culture speed is 150-210 rpm, preferably 180 rpm;

[0055] In step 3), the centrifugal temperature is 2-6°C, preferably 4°C; the centrifugal speed is 8000-12000 rpm, preferably 10000 rpm; the centrifugal time is 15-25 min, preferably 20 min;

[0056] In step 3), the filtration is membrane filtration; the pore size of the membrane is 0.20 to 0.24 μm, preferably 0.22 μm.

[0057] The present invention also provides the use of the microbial agent in preparing products for inhibiting fungal activity and promoting plant growth.

[0058] Preferably, the fungi include one or more of rice sheath blight, corn sheath blight, tobacco target spot, tobacco brown spot, rape sclerotinia, potato late blight, tomato early blight, graminearum Fusarium, rice seedling pathogen, tomato gray leaf spot, rubber tree anthracnose, camellia anthracnose, tea oil anthracnose, tobacco black shank pathogen, pepper anthracnose, Fusarium verticillioides, apple ring spot, tobacco root rot, sweet potato root rot, melon wilt, wheat root rot, corn leaf spot, corn curvature leaf spot and celery leaf spot;

[0059] The plant is rice.

[0060] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0061] Example 1 Screening of strains

[0062] The rice rhizosphere soil was collected from the experimental base of the Rice Research Institute of Shenyang Agricultural University, and the soil microorganisms were isolated by soil dilution plate method: 10 g of soil sample was added to 90 mL of sterile water, shaken for 20 min, 0.5 mL of the solution was added to a 4.5 mL sterile water test tube, and diluted in multiples to make 10 -1 , 10 -2 , 10 -3 , 10 -4 and 10 -5 g / mL five different dilutions of the sample solution; using the dilution plate method, the dilution of 10 -3 and 10 -4 The two concentrations were coated on LB solid medium (water as solvent, including 1% tryptone, 0.5% yeast extract, 0.5% NaCl, 1.5% agar); cultured at 37°C, and when bacterial colonies were formed on the plate, single colonies were picked and divided into zones and streaks on the plate, respectively, and cultured at 37°C to observe whether the colonies were single, and numbered after confirmation;

[0063] All bacterial strains isolated from the soil were inoculated on PDA plates with the sheath blight pathogen Rhizoctonia solani for confrontation culture. The culture was kept at 29°C for 2 days to observe whether there were strains that had an inhibitory effect on the hyphae growth of Rhizoctonia solani. The strains that were initially judged to have an inhibitory effect on Rhizoctonia solani were further screened by confrontation culture, with three replicates for each strain. Finally, it was found that the bacterium numbered snpv-z6 had a significant inhibitory effect on the hyphae growth of Rhizoctonia solani. The colonies of the strain snpv-z6 were light yellow. On the LB plate, the bacteria were round with regular edges, opaque surface, and a slight bulge in the middle. Figure 1 shown.

[0064] Example 2 Identification of strain snpv-z6

[0065] The strain snpv-z6 in Example 1 was inoculated into a liquid LB medium (with water as solvent, including 1% tryptone, 0.5% yeast extract, and 0.5% NaCl), and activated for 12 hours at 180 rpm in a constant temperature shaker at 37°C to obtain a snpv-z6 bacterial solution;

[0066] Gram staining was used to identify the species of the biocontrol strain SNPV-Z6. The specific steps are as follows: the SNPV-Z6 bacterial smear was flame-fixed, stained with crystal violet solution for 1 minute, and the stain was washed off with water; iodine solution was added for 1 minute, and then washed with water; 95% ethanol was added, and the slide was shaken from time to time for 20 seconds until no purple color fell off, and then washed with water; safranin counterstain was added, stained for 1 minute, and then washed with water; after drying, the slide was examined under an oil microscope. Figure 2 As shown;

[0067] from Figure 2 As can be seen, positive bacteria are purple and negative bacteria are light red. Strain SNPV-Z6 is a Gram-negative bacterium.

[0068] The strain SNPV-Z6 was tested for physiological and biochemical indicators. The test indicators and test results are shown in Table 1, where "+" represents positive and "-" represents negative.

[0069] Table 1 Detection results of physiological and biochemical indicators of strain snpv-z6

[0070]

[0071]

[0072] The gDNA of the bacterial strain snpv-z6 was extracted using a bacterial genomic DNA extraction kit from Nanjing Novozymes Biotechnology Co., Ltd.; then the extracted genomic DNA was amplified by PCR using the bacterial 16S rDNA gene universal primers 27-F (5'-AGAGTTTGATCCTGGCTCAG-3') (SEQ ID NO.1) and 1492-R (5'-GGTTACCTTGTTACGACTT-3') (SEQ ID NO.2), and the PCR reaction conditions were: 94°C pre-denaturation for 5 min; 94°C denaturation for 30 s, 56°C annealing for 40 s, 72°C extension for 40 s, 30 cycles, and then 72°C extension for 10 min; the resulting PCR product was sequenced by Sangon Biotech (Shanghai) Co., Ltd., and the measured 16S rDNA sequence of the bacterial strain snpv-z6 (SEQ ID NO.3) BLAST comparison was performed on the NCBI website, and it was found that it had the highest homology with Bacillus siamese, with a similarity of 99%; MEGA-X software was used for sequence analysis and a phylogenetic tree was constructed, such as Figure 3 shown.

[0073] Among them, SEQ ID NO.3 is: CGGCTGGCTCCTAAAAGGTTACCTCACCGACTTCGGGTGTTACAAACTCTCGTGGTGTGACGGGCGGTGTGTACAAGGCCCGGGAACGTATTCACCGCGGCATGCTGATCCGCGATTACTAGCGATTCCAGCTTCACGCAGTCGAGTTGCAGACTGCGATCCGAACTGAGAACAGATTTGTGGGATTGGCTTAACCTCGCGGTTTCGCTGCCCTTTGTTCTGTCCATTGTAGCACGTGTGTAGCCCAGGTCATAAGGGGCATGATGATTTGACGTCATCCCCACCTTCCTCCGGTTTGTCACCGGCAGTCACCTTAGAGTGCCCAACTGAATGCTGGCAACTAAGATCAAGGGTTGCGCTCGTTGCGGGACTTAACCCAACATCTCACGACACGAGCTGACGACAACCATGCACCACCTGTCACTCTGCCCCCGAAGGGGACGTCCTATCTCTAGGATTGTCAGAGGATGTCAAGACCTGGTAAGGTTCTTCGCGTTGCTTCGAATTAAACCACATGCTCCACCGCTTGTGCGGGCCCCCGTCAATTCCTTTGAGTTTCAGTCTTGCGACCGTACTCCCCAGGCGGAGTGCTTAATGCGTTAGCTGCAGCACTAAGGGGCGGAAACCCCCTAACACTTAGCACTCATCGTTTACGGCGTGGACTACCAGGGTATCTAATCCTGTTCGCTCCCCACGCTTTCGCTCCTCAGCGTCAGTTACAGACCAGAGAGTCGCCTTCGCCACTGGTGTTCCTCCACATCTCTACGCATTTCACCGCTACACGTGGAATTCCACTCTCCTCTTCTGCACTCGAGTTCCCCAGAT.

[0074] from Figure 3 It can be seen that the strain SNPV-Z6 is most closely related to Bacillus siamensis. Combined with the morphology of Example 1, it is judged that the strain SNPV-Z6 is Bacillus siamensis.

[0075] The Siamese Bacillus SNPV-Z6, whose Latin name is Bacillus siamensis SNPV-Z6, is deposited in the General Microbiology Center of China Microorganism Culture Collection Administration, located at No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing. The deposit date is September 12, 2024, and the deposit number is CGMCC No.31958.

[0076] Example 3

[0077] 1. Inhibitory effect of Bacillus siamensis SNPV-Z6 on the growth of Rhizoctonia solani

[0078] The Rhizoctonia solani was inoculated in PDA medium (1L PDA solid medium includes: 5g potato powder, 20g glucose, 2.7g agar powder, 1L sterile water) for activation; a bacterial cake with a diameter of 8mm was taken from the Rhizoctonia solani activated in the PDA medium for 48h and inoculated in the center of a new PDA medium, and 10μL of the snpv-z6 bacterial solution in Example 2 was streaked symmetrically on both sides of the bacterial cake, and the siam bacillus snpv-z6 bacterial solution was dried and sealed and stored in a constant temperature incubator at 29°C for culture (treatment group), and the control group was not added with the snpv-z6 bacterial solution; the results are as follows Figure 4 As shown;

[0079] from Figure 4 It can be seen that compared with the control group, Bacillus siameensis snpv-z6 has a significant inhibitory effect on Rhizoctonia solani.

[0080] 2. Inhibitory effect of microbial agents on the growth of Rhizoctonia solani

[0081] Preparation of microbial inoculants:

[0082] 1) The siam bacillus snpv-z6 in Example 1 was inoculated into 10 mL of liquid LB medium, and activated by shaking at 180 rpm in a constant temperature shaker at 37° C. for 12 h to obtain an activated bacterial solution;

[0083] 2) Take 1 mL of activated bacterial solution and inoculate it into 50 mL of liquid LB medium, shake and culture it at 180 rpm in a constant temperature shaker at 37°C for 24 h, and the OD value is 2.7 to obtain the fermentation liquid;

[0084] 3) Centrifuge the fermentation broth at 4°C and 10,000 rpm for 20 min, and take the supernatant; filter the supernatant with a 0.22 μm sterile filter membrane, take the filtrate to obtain the sterile fermentation broth, and store it in a 4°C refrigerator after aliquoting.

[0085] 1 mL of sterile fermentation liquid was added to 9 mL of PDA medium at 45°C, mixed with a gun, and inverted to obtain a PDA medium mixed with sterile fermentation liquid; after the PDA medium mixed with sterile fermentation liquid solidified, Rhizoctonia solani was inoculated in the center of the plate, and inverted at 29°C for culture (treatment group). After culturing for 48 hours, the growth diameter of Rhizoctonia solani was observed and measured, and the data was recorded to calculate the inhibition rate; at the same time, a mixture of 1 mL of sterile water and 9 mL of PDA medium was used as a control group; each treatment included three repetitions, and the entire experiment was repeated three times. The results are as follows: Figure 5 As shown;

[0086] The calculation formula of the antibacterial rate is as follows:

[0087]

[0088] from Figure 5 It can be seen that the aseptic fermentation broth has a significant inhibitory effect on the growth of Rhizoctonia solani, and the inhibition rate on Rhizoctonia solani is 79.16%.

[0089] Example 4 Inhibitory effects of Siamese Bacillus SNPV-Z6 and microbial agents on various plant pathogenic fungi

[0090] The inhibitory effects of Siamese Bacillus SNPV-Z6 and microbial agents on various plant pathogenic fungi were determined according to the steps of Example 3, wherein the fungal species are shown in Table 2. The inhibitory effects of Siamese Bacillus SNPV-Z6 on various plant pathogenic fungi are shown in Table 2. Figure 6 The inhibition rates of microbial agents on various plant pathogenic fungi are shown in Table 2.

[0091] Table 2 The inhibition results of Siamese Bacillus SNPV-Z6 on various plant pathogenic fungi

[0092]

[0093]

[0094]

[0095] From Table 2 and Figure 6 It can be seen that Bacillus siamese SNPV-Z6 and microbial agents have inhibitory effects on the growth of many plant pathogenic fungi.

[0096] Example 5: Control of Rice Sheath Blight by Microbial Agents

[0097] Zhonghua 11 was selected as the experimental rice variety.

[0098] Rice seeds were soaked in sterile water and waited for germination. The germinated seeds were planted in pots, with 15 rice seeds planted in each pot until the three-leaf and one-heart stage. Rhizoctonia solani was activated on a PDA plate with a diameter of 90 mm, and a bacterial cake with a diameter of 8 mm was taken from the edge of the plate and inoculated on the leaf sheath. After 7 days of inoculation, the whole plant was sprayed with the fermentation liquid described in Example 3 (3 mL per plant) as treatment group 1, and the sterile fermentation liquid described in Example 3 was sprayed as treatment group 2. Spraying sterile water was used as the positive control group, and no bacterial cake was used as the blank control group; each treatment group was treated 3 times.

[0099] After the rice became ill, the length of the lesions was observed. The results are shown in Table 3 and Figure 7 As shown; the control effect is calculated according to the length of the lesion, and the calculation formula is as follows:

[0100]

[0101] Table 3 Length of rice lesions

[0102] Group Lesion length (cm) Blank control group 0 Positive control group 8.94±1.72a Treatment Group 1 3.37±0.91b Treatment Group 2 2.33±0.57a

[0103] From Table 3 and Figure 7 It can be seen that compared with the positive control group, the fermentation liquid and the aseptic fermentation liquid have significant control effects on rice blast disease; the control effect of the fermentation liquid on rice blast disease is 62.30%, and the control effect of the aseptic fermentation liquid on rice blast disease is 73.94%.

[0104] Example 6 Effect of microbial agents on the growth promotion of rice

[0105] The fermentation liquid described in Example 3 was diluted 100 times to obtain a diluted agent; 50 mL of the diluted agent was added to a flower pot filled with 200 g of potted seedling soil (taken from the experimental field of Shenyang Agricultural University) as the treatment group, and a flower pot filled with 200 g of potted seedling soil (taken from the experimental field of Shenyang Agricultural University) without the addition of the diluted agent was set as the control group; rice seeds were placed in a beaker and planted at 30°C and soaked in sterile water for germination, and sown when the embryo of the rice seeds grew to 0.5 cm. Each treatment group had 10 pots and repeated 3 times. The rice was cultured in an artificial climate incubator, and each pot was irrigated with sterile water every day. The irrigation amount was 20 mL, the light time was 16 h, the dark time was 8 h, the temperature was 30°C, and the humidity was 30%. After 20 days, the aboveground height, stem diameter, aboveground dry weight and aboveground fresh weight of the rice were measured. The results are shown in Table 4 and Figure 8 shown.

[0106] Table 4 Related physiological indicators of rice

[0107] Physiological indicators Control group Treatment Group Height above ground (cm) 30.84±0.76a 35.61±0.38a Stem diameter (cm) 1.48±0.84b 1.80±0.47a Above ground dry weight (g) 0.029±0.004b 0.034±0.002b Fresh weight above ground (g) 0.17±0.005a 0.21±0.007b

[0108] From Table 4 and Figure 8 It can be seen that the aboveground height of the rice treated with the fermentation liquid increased by 15.47%, the stem diameter increased by 21.62%, the aboveground dry weight increased by 17.24%, and the aboveground fresh weight increased by 23.53% compared with the control group. It can be seen that the fermentation liquid described in Example 3 has a significant promoting effect on the growth of rice.

[0109] It can be seen from the above embodiments that the present invention provides a strain of Bacillus siamese SNPV-Z6 and a microbial agent and a preparation method and application thereof. Bacillus siamese SNPV-Z6 and the microbial agent prepared using the strain can not only inhibit the growth of various plant pathogenic fungi, but also promote the growth and development of rice.

[0110] Although the embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that several improvements and modifications may be made without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A strain of Bacillus siamese SNPV-Z6, characterized in that: The Latin name of the Siamese Bacillus SNPV-Z6 is Bacillus siamensis SNPV-Z6, which is deposited in the General Microbiology Center of the China Culture Collection Administration, located at No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing. The deposit date is September 12, 2024, and the deposit number is CGMCC No. 31958.

2. Use of the siam bacillus snpv-z6 according to claim 1 in the preparation of products for inhibiting fungal activity and promoting plant growth.

3. The use according to claim 2, characterized in that: The fungi include one or more of rice sheath blight, corn sheath blight, tobacco target spot pathogen, tobacco brown spot pathogen, rapeseed sclerotinia, potato late blight, tomato early blight pathogen, graminearum Fusarium, rice seedling pathogen, tomato gray leaf spot pathogen, rubber tree anthracnose, camellia anthracnose, tea oil anthracnose, tobacco black shank pathogen, pepper anthracnose, verticillium fusarium, apple ring rot pathogen, tobacco root rot pathogen, sweet potato root rot pathogen, melon wilt pathogen, wheat root rot pathogen, corn leaf blight pathogen, corn Curvularia leaf spot pathogen and celery leaf blight pathogen.

4. A microbial agent, characterized in that: It comprises the fermentation liquid or aseptic fermentation liquid obtained by fermenting the siam bacillus snpv-z6 according to claim 1.

5. The microbial agent according to claim 4, characterized in that: The method for preparing the fermentation broth comprises the following steps: (1) activating Bacillus siamese SNPV-Z6 at 35-39° C. for 10-14 hours to obtain an activated bacterial solution; (2) Inoculate the activated bacterial liquid into a liquid culture medium and culture at 35-39° C. for 20-28 h to obtain a fermentation liquid.

6. The microbial agent according to claim 5, characterized in that: The method for preparing the aseptic fermentation liquid comprises the following steps: 1) Activating Siamese Bacillus SNPV-Z6 at 35-39° C. for 10-14 hours to obtain an activated bacterial solution; 2) inoculating the activated bacterial solution into a liquid culture medium, culturing at 35-39° C. for 20-28 hours to obtain a fermentation liquid; 3) Centrifuge the fermentation broth and take the supernatant; filter the supernatant and take the filtrate to obtain the sterile fermentation broth.

7. The microbial agent according to claim 6, characterized in that: In step 3), the centrifugal temperature is 2-6°C; the centrifugal speed is 8000-12000 rpm; and the centrifugal time is 15-25 min.

8. The microbial agent according to claim 7, characterized in that: In step 3), the filtration is membrane filtration; the pore size of the membrane is 0.20-0.24 μm.

9. Use of the microbial agent according to any one of claims 4 to 8 in the preparation of products for inhibiting fungal activity and promoting plant growth.

10. The use according to claim 9, characterized in that: The fungi include one or more of rice sheath blight, corn sheath blight, tobacco target spot pathogen, tobacco brown spot pathogen, rapeseed sclerotinia, potato late blight, tomato early blight pathogen, graminearum Fusarium, rice seedling pathogen, tomato gray leaf spot pathogen, rubber tree anthracnose, camellia anthracnose, tea oil anthracnose, tobacco black shank pathogen, pepper anthracnose, verticillium fusarium, apple ring rot pathogen, tobacco root rot pathogen, sweet potato root rot pathogen, melon wilt pathogen, wheat root rot pathogen, corn leaf blight pathogen, corn Curvularia leaf spot pathogen and celery leaf blight pathogen.

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