Salt-tolerant bacillus Sneb2652 and application thereof

Abstract

The invention provides a salt-tolerant bacillus strain Sneb2652 and application thereof, and belongs to the technical field of microorganisms. The salt-tolerant bacillus sp. Sneb2652 is preserved in China General Microbiological Culture Collection Center (CGMCC), the address is No.3, No.1 yard, Beichen West Road, Chaoyang District, Beijing, the preservation date is June 18, 2025, and the preservation number is CGMCC No.34935. The salt-tolerant bacillus sp. Sneb2652 has the advantages that the salt-tolerant bacillus sp. Sneb2652 can be used for preparing the salt-tolerant bacillus sp. Sneb2652, and the salt-tolerant bacillus sp. Sneb2652 can be used for preparing the salt-tolerant bacillus sp. According to the invention, a strain of salt-tolerant bacillus with a good prevention and treatment effect on the soft rot of Chinese cabbage is screened, and the salt-tolerant bacillus also has the effects of inhibiting pectobacterium carotovorum, muskmelon bacterial fruit blotch, apple ring spot, cucumber target leaf spot, apple valsa mali, tomato early blight and sweet melon fruit rot pathogen; the germination of Chinese cabbage seeds and the growth of radicles are facilitated, and the method has good use potential and application prospect in production practice.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of microbial technology, and particularly relates to a salt-tolerant Bacillus sp. Sneb2652 and application thereof. BACKGROUND

[0002] Chinese cabbage soft rot is also known as rot disease, rot or off, and is combined with Chinese cabbage virus disease and downy mildew to be called three major diseases of Chinese cabbage. Chinese cabbage soft rot can occur during the growth, storage and transportation of Chinese cabbage, resulting in rot and deterioration of Chinese cabbage, and even leading to absolute production in severe cases. Pectobacterium carotovorum subsp. Carotovorum (Pcc) is a common pathogenic bacterium of Chinese cabbage soft rot. Studies have found that Pcc can destroy and degrade the parenchyma cells in plant tissues by producing plant cell wall-degrading enzymes, biofilms, motility and other pathogenic factors, resulting in the occurrence of various plant soft rots.

[0003] The prevention and control methods of Chinese cabbage soft rot mainly include planting disease-resistant varieties, biological control, chemical control and the like. Compared with each other, the biological control means is more and more favored by scientific researchers for preventing and controlling soft rot, is friendly to ecological environment, livestock and agriculture, and has a broad prospect. At present, the biological control fungi for preventing and controlling Chinese cabbage soft rot mainly include two kinds: Trichoderma koningiopsis and Phoma herbarica. Trichoderma koningiopsis SMF2 can effectively prevent and control Chinese cabbage soft rot by secreting antibacterial peptide koningin, and can improve the protective enzyme activity in Chinese cabbage and promote plant growth. Phoma herbarica F217-1 can effectively inhibit the growth of Chinese cabbage soft rot bacteria on LB agar plates, and the control efficiency under the condition of in vitro leaf is as high as 75%.

[0004] Bacillus sp. is a kind of gram-positive bacteria capable of producing spores, being aerobic or facultative anaerobic, and widely existing in nature. Bacillus sp. is a kind of non-pathogenic bacteria friendly to natural environment. Bacillus sp. can inhibit various pathogenic bacteria by secreting metabolites, so as to achieve the purpose of preventing and controlling various diseases and pests, and is a kind of safe, non-toxic, green and beneficial microorganism with broad development prospect. Based on this, the present application aims to provide a Bacillus sp. having a biocontrol effect on Chinese cabbage soft rot. SUMMARY

[0005] The present application aims to provide a salt-tolerant Bacillus sp. Sneb2652 and application thereof, and to provide a new biocontrol fungus for preventing and controlling Chinese cabbage soft rot.

[0006] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0007] The application provides a strain of Bacillus halotolerans Sneb2652, which is preserved in the China General Microbiological Culture Collection Center, 1st Courtyard, Beichen West Road, Chaoyang District, Beijing, on June 18, 2025, and has a preservation number of CGMCC No.34935.

[0008] The application provides a preparation containing the Bacillus halotolerans.

[0009] The application provides application of the Bacillus halotolerans or the preparation in prevention and treatment of Chinese cabbage soft rot.

[0010] Preferably, the Chinese cabbage soft rot is caused by Pectobacterium carotovorum subsp.carotovorum.

[0011] The application provides application of the Bacillus halotolerans or the preparation in prevention and treatment of plant pathogenic bacteria, including Pectobacterium carotovorum subsp.carotovorum, Physalospora piricola, Clavibacter michiganensis, Botryosphaeria dothidea, Alternaria solani, Pseudomonas lachrymans and Pseudomonas meliae.

[0012] The application provides application of the Bacillus halotolerans Sneb2652 or the preparation in promotion of plant growth.

[0013] Preferably, the plant includes Chinese cabbage.

[0014] The application provides application of the Bacillus halotolerans or the preparation in degradation of protein, degradation of polysaccharide or biological phosphorus decomposition.

[0015] Compared with the prior art, the application has the following beneficial effects:

[0016] The application screens a strain of Bacillus halotolerans with good prevention and treatment effect on Chinese cabbage soft rot, and the Bacillus halotolerans also has effects of inhibiting Pectobacterium carotovorum subsp.carotovorum, Pseudomonas meliae, Physalospora piricola, Clavibacter michiganensis, Botryosphaeria dothidea, Alternaria solani and Pseudomonas lachrymans, is beneficial to promotion of Chinese cabbage seed germination and radicle growth, and has good use potential and application prospect in production practice. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only belong to the embodiments of the application, and those skilled in the art can also obtain other drawings according to the provided drawings without any creative effort.

[0018] Figure 1 Figure 2 is a morphological diagram of strain Sneb2652 after being cultured in LB solid medium for 48 h in Example 2, A is the back of the colony, and B is the front of the colony;

[0019] Figure 2 Figure 3 is a phylogenetic tree of strain Sneb2652 constructed in Example 2, 1 is a phylogenetic tree of strain Sneb2652 based on 16s rDNA gene, and 2 is a phylogenetic tree of strain Sneb2652 based on gyrB gene;

[0020] Figure 3 Figure 4 is the antibacterial effect of salt-tolerant Bacillus on different pathogenic bacteria in Example 4;

[0021] Figure 4 Figure 5 is the detection result of salt-tolerant Bacillus related enzyme activity in Example 5;

[0022] Figure 5 Figure 6 is the effect of salt-tolerant Bacillus on cabbage seed germination and radicle growth in Example 6;

[0023] Figure 6 Figure 7 is the in vitro control effect determination result of salt-tolerant Bacillus on cabbage soft rot in Example 7, wherein 1 is a ddH2O treatment group, 2 is an LB treatment group, 3 is a pathogenic bacteria treatment group, and 4 is a salt-tolerant Bacillus treatment group;

[0024] Figure 7 Figure 8 is the control effect of salt-tolerant Bacillus on cabbage soft rot under potting experiment conditions in Example 8.

[0025] Deposit Description

[0026] The salt-tolerant Bacillus Sneb2652 is deposited with the China General Microbiological Culture Collection Center, located at No. 1, Beichen West Road, Yard 3, Chaoyang District, Beijing, on June 18, 2025, and has the accession number CGMCC No. 34935. DETAILED DESCRIPTION

[0027] The technical solutions provided by the present application will be described in detail below in combination with examples, but they should not be understood as limiting the scope of protection of the present application.

[0028] The strains Sneb2652, the test pathogenic bacteria [Pectobacterium carotovorum subsp. carotovorum, Acidovorax citrulli] and the test pathogenic fungi [Botryosphaeria dothidea, Corynespora cassiicola, Valsa mali, Alternaria solani (Ellis et Martin) Jones et Grout, Fusarium rosesum Link] used in the following examples were provided by the Institute of Northern Nematodes, Shenyang Agricultural University. The test Chinese cabbage variety was Zhenong Zaoshu No. 5, which has a certain resistance to Chinese cabbage soft rot and is widely planted in the areas south of the Yangtze River.

[0029] Example 1 Obtaining of strain Sneb2652

[0030] A soybean field soil sample was taken from Lüliang City, Shanxi Province (longitude 111.475°, latitude 37.1438°), 5 g of the soil sample was added to a 250 mL triangular flask containing 45 mL of sterile water, gradient diluted, and 25 μL of the soil suspension with dilution degrees of 10 -2 , 10 -3 , and 10 -4 was respectively coated on LB solid culture medium, and incubated at 37°C for 12 h. The strain was isolated and purified by plate dilution method, the strain fermentation broth was mixed with 30% glycerol, and stored in a freezer at -80°C. The strain Sneb2652 was obtained.

[0031] Example 2 Identification of strain Sneb2652

[0032] The strain was identified by morphological, physiological and biochemical characteristics and molecular biology methods to determine the taxonomic status of the strain.

[0033] 1. Morphological observation

[0034] The strain Sneb2652 was incubated in LB solid culture medium for 48 h, and the colony morphology was observed in terms of color, shape, presence or absence of luster, whether the edge was neat, and whether there was a protrusion.

[0035] The results are shown in Figure 1 (A is the back of the colony, and B is the front of the colony). The colony is protruding, milky white, opaque and smooth, the colony is round or oval, wet, wrinkled, and the edge is neat.

[0036] 2. Physiological and biochemical characteristics identification

[0037] According to the eighth edition of Bergey's Manual of Determinative Bacteriology and Handbook of Common Bacteria and related literatures, physiological and biochemical characteristics were identified from the aspects of gram staining reaction, malonate utilization, sorbitol, hydrogen sulfide, lactose, gelatin liquefaction, rhamnose, lysozyme, maltose, etc.

[0038] The gram staining result of strain Sneb2652 under optical microscope was purple, which was a gram-positive bacterium.

[0039] As shown in Table 1, maltose, malonate utilization, H2S production, lactose, lysozyme, xylose, L-rhamnose, lysine decarboxylase, raffinose, galactose, inositol, rhamnose and proteose peptone water were negative, sorbitol, fructose, glucose, mannitol and gelatin liquefaction were positive, and strain Sneb2652 met the physiological and biochemical characteristics of Bacillus.

[0040] Table 1 Identification results of physiological and biochemical characteristics

[0041] Item Item Maltose - Malonate utilization - Sorbitol + Fructose + HS production - Glucose + Lactose - Lysozyme - Xylose - Mannitol + L-rhamnose - Gelatin liquefaction + Lysine decarboxylase - Raffinose - Galactose - Myo-inositol Rhamnose - Peptone water -

[0042] Note: "+" in the table indicates positive, "-" indicates negative

[0043] 3. Molecular biology identification

[0044] The genomic DNA of the biocontrol bacteria was extracted according to the instructions of the bacterial DNA extraction kit. The genomic DNA of the strain was subjected to PCR amplification using bacterial 16S rDNA universal primers 27F / 1492R and gyrB primers gyrB-F / gyrB-R. The primer sequences are shown in Table 2, the PCR reaction system is shown in Table 3, and the PCR amplification program is shown in Tables 4 and 5.

[0045] Table 2 Primer sequences

[0046] As shown in SEQ ID NO. 1-SEQ ID NO. 4, Y represents C or T, N represents A, G, C or T, and R represents A or G

[0047] Table 3 PCR reaction system

[0048] Ingredient Amount Upstream primer 1 μL Downstream primer 1 μL DNA 2 μL 2 x Taq Master Mix (Dye olus) 12.5 μL ddH2O 8.5 μL Total 25 μL

[0049] Table 4 PCR amplification program of bacterial 16S rDNA gene

[0050]

[0051] Table 5 PCR amplification program of bacterial gyrB gene

[0052]

[0053] PCR products were detected by 1.2% agarose gel electrophoresis. After the PCR products were verified, they were sent to Shenguo Bioengineering (Shanghai) Co., Ltd. for PCR product sequencing. The sequencing results were analyzed by BLAST comparison in the NBCI database, and the phylogenetic tree was constructed by the Neighbor-joining method using MEGA7 software.

[0054] The results show that the bands with the expected size are obtained by PCR amplification with 27F / 1492R and gyrB-F / gyrB-R as primers, respectively, using the genomic DNA of strain Sneb2652 as a template. The constructed phylogenetic tree is shown in Figure 2 Figure 1, in which 1 is the phylogenetic tree of strain Sneb2652 based on 16s rDNA gene, and 2 is the phylogenetic tree of strain Sneb2652 based on gyrB gene. It can be seen that the 16s rDNA sequence and the gyrB sequence of strain Sneb2652 both have high homology with Bacillus halotolerans. The 16S rDNA and gyrB gene sequences of strain Sneb2652 have been submitted to the GenBank database, with the 16S rDNA gene sequence number being PV750832 and the gyrB gene sequence number being PV916014.

[0055] Therefore, through morphological characteristics, physiological and biochemical characteristics identification and molecular biology identification results, strain Sneb2652 is named Bacillus halotolerans Sneb2652, which is preserved in the China General Microbiological Culture Collection Center, located at No. 1, Beichen West Road, Yard 3, Chaoyang District, Beijing, with the preservation date being June 18, 2025, and the preservation number being CGMCC No. 34935.

[0056] Example 3 Inhibition effect of Bacillus halotolerans Sneb2652 on Xanthomonas campestris

[0057] 1. Preparation of fermentation broth of Bacillus halotolerans Sneb2652

[0058] The frozen Bacillus halotolerans Sneb2652 was streaked on LB solid medium, and the dried bacterial liquid was placed in a 28°C incubator for 12h. The activated single colony was picked into a test tube containing 3mL LB liquid medium, and was placed in a 37°C, 200r / min shaking incubator for 12h. The concentration was adjusted to 1×10 8 CFU / mL with LB liquid medium.

[0059] 2. Preparation of fermentation broth of Xanthomonas campestris

[0060] Take the frozen Chinese cabbage soft rot pathogen [Pectobacterium carotovorum subsp. carotovorum] on LB solid medium, dry the bacterial liquid and place it in a 28℃ incubator for 12h. The activated pathogen was picked into a test tube containing 3mL LB liquid medium, and placed in a 37℃, 200r / min shaker for 12h. Adjust to 1x10 8 CFU / mL with LB liquid medium.

[0061] 3. Plate antagonism experiment

[0062] Add 150μL of Chinese cabbage soft rot pathogen fermentation broth to 150mL of 50℃ LB solid medium and mix well to make a pathogen-containing plate.

[0063] Take 1μL of salt-tolerant Bacillus Sneb2652 fermentation broth and add it to 4 positions 2cm from the center of the plate, with 3 replicates. Set up a blank control group (CK) without adding salt-tolerant Bacillus Sneb2652 fermentation broth. Incubate in a 28℃ constant temperature incubator for 24h, observe and measure the diameter of the inhibition zone. The results are shown in Table 6, indicating that salt-tolerant Bacillus Sneb2652 has a significant inhibitory effect on Chinese cabbage soft rot pathogen.

[0064] Table 6 Plate antagonism ability of salt-tolerant Bacillus Sneb2652 against Chinese cabbage soft rot pathogen

[0065] Treatment Inhibition zone diameter (cm) CK 0.00±0.00b Sneb2652 1.08±0.09a

[0066] Example 4 Inhibitory effect of salt-tolerant Bacillus Sneb2652 on other pathogenic bacteria

[0067] 1. Preparation of salt-tolerant Bacillus Sneb2652 fermentation broth

[0068] Take the frozen salt-tolerant Bacillus Sneb2652 on LB solid medium, dry the bacterial liquid and place it in a 28℃ incubator for 12h; pick the activated single colony into a test tube containing 3mL LB liquid medium, and place it in a 37℃, 200r / min shaker for 12h. Adjust to 1x10 8 CFU / mL with LB liquid medium.

[0069] 2. Inhibitory activity of salt-tolerant Bacillus Sneb2652 on pathogenic fungi

[0070] Activation of pathogenic fungi: Take the frozen 5 pathogenic fungi cakes to 2% PDA plates and place them in a 28℃ incubator for 5d.

[0071] Plate confrontation experiment: A 5mm diameter puncher was used to punch a bacterial cake along the outer edge of the pathogenic bacteria colony, and the bacterial cake was inoculated in the center of a 2% PDA plate. 1 μL of salt-tolerant Bacillus Sneb2652 fermentation broth was dropped at a distance of 2.5 cm from the center of the plate with a pipette, and the bacterial liquid was blown dry and sealed. A 2% PDA plate inoculated with only the pathogenic bacterial cake was used as a control (CK), and each group had 3 replicates. The plates were placed in a 28°C incubator and cultured for 7 days.

[0072] When the control group of pathogenic bacteria grew on the culture dish, the radii of the control and treatment pathogenic bacterial colonies were recorded and the inhibition rate was calculated.

[0073] Inhibition rate (%) = [(control colony diameter - treatment colony diameter) / control colony diameter] x 100%

[0074] 3. Inhibition activity of salt-tolerant Bacillus Sneb2652 on pathogenic bacteria

[0075] Preparation of Acidovorax citrulli fermentation broth: The frozen bacteria were streaked on LB solid medium, and the bacterial liquid was blown dry and placed in a 28°C incubator for 12 h. The activated pathogenic bacteria were picked into a test tube containing 3 mL of LB liquid medium, and were placed in a 37°C, 200 r / min shaker for 12 h. The LB liquid medium was adjusted to 1 x 10 8 CFU / mL.

[0076] Plate confrontation experiment: 150 μL of Acidovorax citrulli fermentation broth was added to 150 mL of 50°C LB solid medium and mixed well to prepare a plate containing pathogenic bacteria. 1 μL of salt-tolerant Bacillus fermentation broth (1 x 10 8 CFU / mL) was added to 4 positions at a distance of 2 cm from the center of the plate with a pipette, and each dish was inoculated with one bacterium to be tested. Each bacterium to be tested was set up in triplicate, and a plate containing pathogenic bacteria without the addition of the bacterium to be tested was used as a blank control. The plates were incubated in a 28°C constant temperature incubator for 24 h, and the inhibition zone diameter was observed and measured.

[0077] 4. Results

[0078] The inhibition effect of salt-tolerant Bacillus Sneb2652 on the above-mentioned 5 kinds of pathogenic fungi and 1 kind of pathogenic bacteria was as shown in Table 6, and the inhibition rate on pathogenic fungi was as shown in Table 7. The inhibition zone diameter of Acidovorax citrulli was 1.00 ± 0.13 cm, and the CK was 0.00 ± 0.00 cm. It can be seen that salt-tolerant Bacillus has an inhibitory effect on the above-mentioned 5 kinds of pathogenic fungi and 1 kind of pathogenic bacteria. Figure 3

[0079] ​Table 7 Inhibition effect of salt-tolerant Bacillus on pathogenic fungi

[0080]

[0081] Example 5 Detection of salt-tolerant Bacillus Sneb2652 related enzyme activity

[0082] 1 μL of the fermentation broth of salt-tolerant Bacillus Sneb2652 was dropped in the center of the prepared amylase detection plate, protease detection plate, cellulase detection plate, phosphatase detection plate and HCN detection plate, respectively. After the bacteria liquid was blown dry, it was sealed and placed in a 37°C incubator for 7 days. Whether transparent circles appeared around the colonies was observed. Each treatment was repeated 3 times.

[0083] As shown in Table 8, salt-tolerant Bacillus Sneb2652 can produce protease, amylase, phosphatase and HCN, and does not produce cellulase. It is shown that salt-tolerant Bacillus Sneb2652 has excellent degradation performance, can decompose protein substances, polysaccharides such as starch and phosphorus-containing organic matter, and inhibit the growth of soil pathogenic bacteria. Figure 4

[0084] The culture medium and components used in this example are as follows (all culture media are sterilized at 121°C for 30 min):

[0085] Amylase detection plate: soluble starch 20.0 g, potassium nitrate 1.0 g, potassium phosphate dibasic 5.0 g, ferrous sulfate heptahydrate 0.01 g, sodium chloride 0.5 g, manganese sulfate heptahydrate 0.5 g, agar powder 20.0 g, deionized water 1000 mL, pH adjusted to 7.2-7.4.

[0086] Protease detection plate: skimmed milk 100 mL, agar powder 20.0 g, deionized water 1000 mL.

[0087] Cellulase detection plate: cellulose powder 5 g, sodium nitrate 1 g, potassium chloride 0.5 g, magnesium sulfate 0.5 g, yeast extract powder 0.5 g, congo red 0.2 g, acid hydrolyzed casein 0.5 g, sodium phosphate dibasic 1.2 g, potassium phosphate monobasic 0.9 g, agar powder 15 g, deionized water 1000 mL.

[0088] Phosphatase detection plate: yeast extract powder 0.5 g, ammonium sulfate 0.5 g, calcium phosphate 5 g, magnesium chloride 0.1 g, glucose 10 g, manganese sulfate monohydrate 0.1 mg, ferrous sulfate 0.1 mg, agar powder 15 g, deionized water 1000 mL.

[0089] HCN detection plate: potato 200 g, glucose 20 g, glycine 4.4 g, agar 15 g, deionized water 1000 mL.

[0090] ​Effect of Bacillus halodurans Sneb2652 on seed germination and radicle growth of Brassica chinensis

[0091] Healthy and full Brassica chinensis seeds were selected, soaked in 1% NaClO solution for 3 min, washed with sterile water for 3 times, and dried on sterile filter paper for standby. The Brassica chinensis seeds were soaked in the fermentation broth of Bacillus halodurans Sneb2652 (1×10 8 CFU / mL) for 10 min, placed in a culture dish covered with sterile moist filter paper, 10 seeds were evenly placed in each culture dish, the control group (CK) was treated with the same amount of ddH2O, and the LB group was treated with the same amount of LB liquid medium, each treatment was repeated 3 times. The culture dishes were incubated in a 25°C incubator for 2 days. The number of germinated seeds, radicle length, fresh weight and dry weight of each treatment were recorded, and the germination rate was calculated.

[0092] Germination rate (%) = number of germinated seeds / number of treated seeds × 100%

[0093] The results are shown in Table 8 and Figure 5 Compared with the LB group, the fresh weight and dry weight of Brassica chinensis seeds treated with Bacillus halodurans Sneb2652 significantly increased. It can be seen that the use of Bacillus halodurans Sneb2652 fermentation broth for seed soaking and coating treatment can promote the growth of Brassica chinensis plants and has no inhibitory effect on seed germination, which has good potential and application prospect in production practice.

[0094] Table 8 Effect of Bacillus halodurans on seed germination and radicle growth of Brassica chinensis

[0095]

[0096] Example 7 In vitro control effect of Bacillus halodurans Sneb2652 on Brassica chinensis soft rot

[0097] Healthy and full Brassica chinensis seeds were selected, soaked in 1% NaClO solution for 3 min, washed with sterile water for 3 times, and dried on sterile filter paper for standby. The Brassica chinensis seeds were soaked in the fermentation broth of Bacillus halodurans Sneb2652 (1×10 8 CFU / mL) for 10 min, placed in a culture dish covered with sterile moist filter paper, 10 seeds were evenly placed in each culture dish, the control group (CK) was treated with the same amount of ddH2O, and the LB group was treated with the same amount of LB liquid medium, each treatment was repeated 3 times. The culture dishes were incubated in a 25°C incubator for 2 days. The number of germinated seeds, radicle length, fresh weight and dry weight of each treatment were recorded, and the germination rate was calculated. 8CFU / mL) was inoculated onto leaf wounds, with treatments of pathogen inoculation without biocontrol bacteria and treatment with only ddH2O and LB medium serving as controls. Each treatment was replicated in triplicate. The leaves were wrapped in aluminum foil and incubated at 28°C for 48 hours. The presence of lesions was then observed. The size of lesions in both the control and treatment areas was measured using the cross-sectional method, and the control effect was calculated.

[0098] Control efficacy (%) = (Diameter of lesions in control group - Diameter of lesions in treatment group) / Diameter of lesions in control group × 100%

[0099] The results are as follows Figure 6 As shown, group 1 represents the ddH2O treatment group, group 2 the LB treatment group, group 3 the pathogen treatment group, and group 4 the halophilic Bacillus Sneb2652 treatment group. It can be seen that halophilic Bacillus Sneb2652 has a good control effect on the soft rot pathogen of detached cabbage leaves. 48 hours after inoculation with the pathogen, the pathogen-treated group showed larger lesions with a foul odor, with a lesion diameter of 1.50 cm (average). The halophilic Bacillus Sneb2652 treatment resulted in smaller lesions on the cabbage leaves, with a lesion diameter of 0.63 cm (average), and the control effect on the detached soft rot pathogen of cabbage was 57.89%.

[0100] Example 8: Pot experiment on the control of soft rot in Chinese cabbage using halophilic Bacillus Sneb2652

[0101] Select uniformly sized Chinese cabbage seeds, place them in 55℃ warm water and stir for 10 minutes. After the water cools naturally to room temperature, continue soaking for 6 hours. Remove the seeds, wrap them in sterile cotton cloth, and place them in a 28℃ incubator for 48 hours to germinate. Once the seeds show white sprouts, they can be sown in 50-cell trays. After the Chinese cabbage has grown 3 true leaves, inoculate using a spray method with a 1×10⁻⁶ concentration of [unspecified agent]. 8 The pathogen fermentation broth at CFU / mL was evenly sprayed onto the leaves of three-leaf Chinese cabbage seedlings of roughly the same size, with 10 mL applied to each seedling. Seedling trays were cultured in a greenhouse (14 hours light, 10 hours dark). One day later, the seedlings were evenly sprayed with 1×10⁻⁶ CFU / mL of halophilic Bacillus Sneb2652 fermentation broth. 8 CFU / mL), 10 mL per seedling was sprayed. The treatment with pathogen inoculation only served as a control, and the treatment with ddH2O and LB liquid medium but without pathogen inoculation served as a blank control. Each treatment was replicated three times. Disease incidence was assessed after 3 days, and the disease index and control effect were calculated. Disease severity was graded according to the disease grading standards in the "Guidelines for Field Efficacy Trials of Pesticides" based on the proportion of lesion area to leaf area (Table 9). Results are shown in Table 10 and... Figure 7 As shown.

[0102] Disease index =∑[(number of diseased leaves of each grade × grade number) / (total number of leaves surveyed × highest grade number)] × 100 Control effect (%) = [(disease index of control group - disease index of treatment group) / disease index of control group] × 100%

[0103] Table 9 Disease grading standard

[0104] Disease classification Leaf area ratio of lesion area 0 level 0 1 level 1％～5％ 3 level 6％～10％ 5 level 11％～25％ 7 level 26％～50％ 9 level 50% or more

[0105] Table 10 Pot experiment of salt-tolerant Bacillus against Chinese cabbage soft rot

[0106]

[0107] It can be seen from Table 10 and Figure 7 It can be seen from Table 10 and

[0108] The above only describes the preferred embodiments of the present application, and it should be noted that those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A strain of Bacillus halotolerans Sneb2652, which is deposited with the China General Microbiological Culture Collection Center, located at No.1, Yihuangyuan, Beichenxi Road, Chaoyang District, Beijing, on June 18, 2025, and has the accession number of CGMCC No.34935. 2.A preparation comprising the Bacillus halotolerans Sneb2652 of claim 1. 3.Use of the Bacillus halotolerans Sneb2652 of claim 1 or the preparation of claim 2 in preventing and treating Chinese cabbage soft rot.

4. The use according to claim 3, wherein the compound is ###0002### The Chinese cabbage soft rot is caused by Pectobacterium carotovorum subsp.carotovorum.

5. Use of the salt-tolerant Bacillus of claim 1 or the preparation of claim 2 for controlling plant pathogenic fungi, characterized in that, The plant pathogens include Pectobacterium carotovorum subsp.carotovorum, Physalospora piricola, Clavibacter michiganensis, Botryosphaeria dothidea, Alternaria solani, Aspergillus flavus and Pseudomonas lachrymans. 6.Use of the Bacillus halotolerans Sneb2652 of claim 1 or the preparation of claim 2 in promoting plant growth.

7. Use according to claim 6, wherein The plants include Chinese cabbage. 8.Use of the Bacillus halotolerans Sneb2652 of claim 1 or the preparation of claim 2 in degrading protein, degrading polysaccharide or biologically dephosphorizing.

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