Bacillus velezensis and its application in inhibiting panax ginseng root rot

Abstract

The present application belongs to the field of microbial technology, and relates to a bacillus velezensis strain Ba25 and application thereof in inhibiting panax quinquefolium root rot. The preservation number of the strain Ba25 is CGMCC NO. 38979. The present application also relates to a microbial preparation and a microbial fertilizer containing the strain Ba25, a method for inhibiting panax quinquefolium root rot, application in improving plant growth potential, and use of the strain Ba25. The strain Ba25 can effectively inhibit panax quinquefolium root rot pathogen, has the ability of nitrogen fixation, ammonia production and proteinase production, and thus has the potential of improving plant growth.

Description

Technical Field

[0001] This invention belongs to the field of microbial technology and discloses a strain of Bacillus belye that inhibits root rot in American ginseng. Bacillus velezensis ) strains and their applications. Background Technology

[0002] American ginseng ( Panax quinquefolium Also known as American ginseng or Panax quinquefolius, it belongs to the genus Panax in the family Araliaceae. Panax Panax is a perennial herb, first recorded in my country in the "Illustrated Compendium of Materia Medica." Like traditional Chinese ginseng, it is a precious medicinal herb with a slightly bitter and sweet taste and cooling properties. It is believed to replenish qi and nourish yin, clear heat, and generate fluids. The name Panax originally means "panax" in Greek. It has a history of over 300 years in China. The "Seeking the Origins of Materia Medica" states: "Lung qi originates from the kidneys. Most medicines that benefit lung qi are slightly cold, but this one is bitter and cold. It is only beneficial for those suffering from qi deficiency due to excessive fire, cough with phlegm and blood, or fatigue and loss of essence." It is believed to replenish qi and nourish yin, clear heat, and generate fluids without causing dryness or heat.

[0003] American ginseng contains a variety of chemical components, mainly including saponins, polysaccharides, organic acids, sterols, flavonoids, polyacetylene, and volatile oils, as well as nutrients such as vitamins, amino acids, carbohydrates, and trace elements. Ginsenosides and polysaccharides are the most abundant and are the main active ingredients of American ginseng. Modern pharmacological studies have shown that American ginseng has anti-tumor, cardiovascular protective, anti-oxidative stress, insulin resistance-improving, lipid-lowering, anti-fatigue, and immune-enhancing effects.

[0004] In 2023, dried roots of American ginseng were included in the list of substances traditionally used as both food and medicinal materials. With the rapid development of my country's health industry, American ginseng, due to its dual nature as both food and medicine, has shown broad application prospects and market potential in the fields of food, health products, and cosmetics. The consumer base for American ginseng is gradually becoming younger, market demand is increasing daily, and the planting area is continuously expanding. Currently, China has become the world's largest consumer and second-largest producer of American ginseng.

[0005] American ginseng has a long growth cycle, typically 4-5 years. With increasing cultivation time, pathogens accumulate in the soil, primarily affecting the roots and threatening yield and quality. Root rot, often called "plant cancer," is one of the most destructive plant diseases impacting ginseng yield and quality. Normally, the incidence of root rot in medicinal plants is between 10% and 30%, but in severe cases, it can reach 70% to 80%, even causing complete crop failure. Research indicates that root rot in American ginseng is related to changes in rhizosphere soil microorganisms; a decrease in beneficial microorganisms leads to an increase in pathogens such as Fusarium spp. Fusarium ) and the genus *Ceratophyllum* ( IlyonectriaThe proliferation of fungi can lead to diseases affecting American ginseng, primarily damaging the roots and rhizomes of seedlings, with peak incidence occurring in July and August each year. In the early stages, the above-ground parts show no obvious symptoms; in later stages, the roots become dark brown and rotten, and the leaves wilt and die. Commonly used pesticides in production include metalaxyl-mancozeb, chlorobromoisocyanuric acid, thiophanate-methyl, methyl thiophanate, tebuconazole, and sennamycin. However, the overuse of pesticides is frequent, directly impacting the quality of American ginseng and its safety in clinical use.

[0006] Therefore, developing green, efficient, and safe biocontrol technologies has become an important research direction. By screening biocontrol strains with antagonistic effects, it is hoped that the use of chemical pesticides can be effectively replaced or reduced, the occurrence of pathogens can be inhibited, and the soil microecological balance can be maintained, thereby significantly improving the yield and quality of American ginseng. Summary of the Invention

[0007] In view of this, the present invention provides a strain of Bacillus belye that inhibits root rot in American ginseng and its application, so as to effectively inhibit root rot in American ginseng, replace or reduce the use of chemical pesticides, and maintain the soil microecological balance.

[0008] On one hand, this invention provides a Bacillus vesiculosus strain Ba25 that inhibits root rot in American ginseng. Strain Ba25 was obtained on November 18, 2023, from the rhizosphere soil of a four-year-old American ginseng plant collected in Wendeng District, Weihai City, Shandong Province. It was deposited on June 3, 2026, at the China General Microbiological Culture Collection Center (CGMCC), located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences, 100101, China; accession number: CGMCC No. 38979.

[0009] In an embodiment of the present invention, the 16S rRNA gene sequence of Bacillus vesiculosus strain Ba25 is shown in SEQ ID NO: 1.

[0010] In an embodiment of the present invention, strain Ba25 is streaked on a TSA (Tryptic Soy Agar) medium plate and incubated in the dark at 25°C for 2 days. The colonies of strain Ba25 are light yellow with irregular edges, raised and wrinkled surfaces, and opaque texture.

[0011] In a second aspect, the present invention provides a microbial preparation comprising Bacillus belye strain Ba25.

[0012] In a third aspect, the present invention provides a microbial fertilizer comprising the Bacillus berberis strain Ba25 described in the first aspect or the microbial preparation described in the second aspect.

[0013] In a fourth aspect, the present invention provides a method for inhibiting root rot in American ginseng, comprising applying to American ginseng the Bacillus berberis strain Ba25 described in the first aspect, the microbial preparation described in the second aspect, or the microbial fertilizer described in the third aspect.

[0014] In embodiments of the present invention, root rot is caused by fungi of the genus *Fusarium* or *Erythrophagus*. In a specific embodiment, the *Fusarium* fungus is *Fusarium oxysporum* (…). F. oxysporum ) or Fusarium solani ( F. solani In the specific implementation plan, *Cryptocoryne* fungi are... Ilyonectria mors-panacis or Ilyonectria destructans .

[0015] In a fifth aspect, the present invention provides a method for promoting plant growth, comprising applying to plants the Bacillus berberis strain Ba25 described in the first aspect, the microbial preparation described in the second aspect, or the microbial fertilizer described in the third aspect.

[0016] In embodiments of the invention, the plant may be, for example, American ginseng. In a fifth aspect, the invention provides the use of the *Bacillus vesiculosus* strain Ba25 described in the first aspect, the microbial preparation described in the second aspect, or the microbial fertilizer described in the third aspect in the following ways: 1) inhibiting root rot in American ginseng; 2) preparing a microbial preparation for inhibiting root rot in American ginseng; 3) fixing nitrogen; 4) producing ammonia; 5) producing proteases.

[0017] The *Bacillus belyssus* strain Ba25 provided by this invention can effectively inhibit *Fusarium* species such as *Fusarium oxysporum* and *Fusarium solanum*, as well as *Rhizoctonia solani* species such as... Ilyonectria mors-panacis and Ilyonectria destructans, This effectively inhibits root rot in American ginseng. The *Bacillus belye* strain of this invention also possesses the ability to promote plant growth, fix nitrogen, produce ammonia, and produce proteases, thus serving as a microbial preparation for promoting plant growth and development.

[0018] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0019] Figure 1 The morphology of four ginseng root rot pathogens was shown.

[0020] Figure 2 This demonstrates the pathogenicity of the pathogen causing root rot in American ginseng.

[0021] Figure 3The study demonstrated that strain Ba25 inhibited the growth of four ginseng root rot pathogens.

[0022] Figure 4 The colony morphology of strain Ba25 is shown.

[0023] Figure 5 The growth-promoting properties of strain Ba25 were demonstrated.

[0024] Figure 6 The biocontrol characteristics of strain Ba25 were demonstrated.

[0025] Bacillus belye strain Ba25 was obtained from the rhizosphere soil of a four-year-old American ginseng collected on November 18, 2023, in Wendeng District, Weihai City, Shandong Province. It was deposited on June 3, 2026, at the China General Microbiological Culture Collection Center (CGMCC), located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences, 100101, China; accession number: CGMCC No. 38979. The taxonomic name of strain Ba25 is Bacillus belye, and its Latin scientific name is... Bacillus velezensis . Detailed Implementation

[0026] The preferred embodiments of the present invention will now be described in detail with reference to examples. It should be understood that the following examples are given for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Those skilled in the art can make various modifications and substitutions to the present invention without departing from its spirit and intent, and all such modifications and substitutions fall within the scope of protection claimed in the present invention.

[0027] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0028] Unless otherwise specified, all examples were performed under standard experimental conditions, such as those described in Sambrook et al., Molecular Cloning: a Laboratory Manual (Sambrook J & Russell DW, 2012), or as recommended by the manufacturer’s instructions.

[0029] Unless otherwise specified or obvious from the context, the term "about" as used herein shall be understood to mean within the normal tolerance range in the art, such as within two standard deviations of the average. "About" may be understood to mean within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the specified value. Unless the context clearly indicates otherwise, all numerical values ​​provided in this specification and claims may be modified by the term "about".

[0030] The culture medium formulation used in the examples is as follows: PDA medium: Potato (peeled): 200 g, glucose: 20 g, agar powder: 12 g, deionized water: 1 L.

[0031] TSA medium: 17.0 g tryptone, 3.0 g plant peptone, 5.0 g NaCl, 2.5 g glucose, 2.5 g K2HPO4, 15 g agar, 1 L deionized water.

[0032] TSB medium: 17.0 g tryptone, 3.0 g plant peptone, 5.0 g NaCl, 2.5 g glucose, 2.5 g K2HPO4, 1 L deionized water.

[0033] Protease-producing culture medium: 3 g skim milk powder, 3 g agar powder, 200 mL deionized water.

[0034] The Assambe solid medium (catalog number: 12103) and peptone water medium (catalog number: 10180) used in the experiment were purchased from Qingdao Rishui Biotechnology Co., Ltd.; the inorganic phosphorus bacteria medium (catalog number: HB8670), organic phosphorus bacteria medium (catalog number: HB8549-1), siderophore detection medium (catalog number: HB9132), and cellulose Congo red medium (catalog number: HB8638) were purchased from Qingdao High-tech Industrial Park Haibo Biotechnology Co., Ltd. All media were prepared and sterilized according to the corresponding manufacturer's product instructions before use. L-Tryptophan (product number: 79767B) was purchased from Shanghai Adamas Reagent Co., Ltd.; Indoleacetic acid standard solution (batch number: 20250409) and Salkowski colorimetric solution (product number: PH1941) were purchased from Feijing Biotechnology Co., Ltd.; Skim milk powder (product number: 1172GR100) was purchased from BIOFROXX; Nessler solvent (product number: 110702070) was purchased from Hunan Bickman Holding Co., Ltd. Glucose (item number 10010518) and sodium chloride (item number 10019318) were purchased from Sinopharm Chemical Reagent Co., Ltd.; agar (item number A8190) was purchased from Beijing Solarbio Science & Technology Co., Ltd.; tryptone (item number LP0042B) was purchased from OXOID; and plant peptone (item number B874857) and K2HPO4 (item number P816382) were purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0035] Example 1. Isolation, purification, culture, identification, and pathogenicity testing of strains causing root rot in American ginseng. 1.1 Plant material: Four-year-old diseased American ginseng roots collected in Wendeng District, Weihai City, Shandong Province in November 2023.

[0036] 1.2 Isolation, purification, and culture of the pathogen causing root rot The pathogen was isolated, purified, and cultured using a tissue block isolation method. Diseased ginseng roots were taken and sequentially rinsed with sterile water, disinfected with 75% ethanol for 30 seconds, disinfected with 5% sodium hypochlorite for 3 minutes, rinsed once with sterile water, soaked in a solution of antibiotics (containing 100 µg / mL streptomycin sulfate and 100 µg / mL potassium penicillin) for 10 minutes, rinsed three times with sterile water, and dried with sterile filter paper. 0.5 cm × 0.5 cm tissue blocks were cut from the diseased ginseng root at the junction of diseased and healthy tissue using a sterile scalpel. These blocks were inoculated onto PDA circular agar plates (d = 1.5 cm) containing antibiotics (100 µg / mL streptomycin sulfate and 100 µg / mL potassium penicillin), with 9 blocks per plate. The plates were incubated at 25°C in the dark until mycelia grew around the tissue blocks. Mycelia were picked from the edge of the colonies and transferred to new PDA plates. Purification was continued until the colony morphology stabilized, and the plates were then stored.

[0037] Four bacterial strains were isolated and named C0701, C0795, C0849, and C0872, respectively. The colony morphology of the four pathogens on PDA medium was observed. The results showed that strain C0701 colonies were white with neat edges, a compact texture, and filamentous hyphae; strain C0795 colonies were purplish-red with well-developed, cottony hyphae; strain C0849 colonies were white with a compact texture and a velvety surface; and strain C0872 colonies were brownish-yellow with well-developed, felt-like hyphae. Figure 1 As shown.

[0038] 1.3 Molecular biological identification of pathogenic bacterial strains C0701, C0795, C0849, and C0872 Total DNA was extracted from four bacterial strains using the CTAB method. PCR amplification was performed on the extracted DNA using primers ITS1F (5'-CTTGGTCATTTAGAGGAAGTAA-3') and ITS4 (5'-TCCTCCGCTTATTGATATGC-3'). The PCR reaction mixture consisted of 8.5 μL ddH2O, 1 μL ITS1F, 1 μL ITS4, 12.5 μL Taq polymerase, and 2 μL DNA template, for a total reaction volume of 25 μL. PCR cycling consisted of: 95℃ pre-denaturation for 5 min, 1 cycle; 94℃ denaturation for 1 min, 52℃ annealing for 50 s, 72℃ extension for 1 min, 35 cycles; and a final extension at 72℃ for 7 min. The amplified products were sent to Suzhou Genewiz Biotechnology Co., Ltd. for sequencing. BLAST alignment of the sequences with the National Center for Biotechnology Information (NCBI) database was performed, and the taxonomic position of the pathogens was determined based on morphological characteristics.

[0039] The sequencing sequences of the four strains were compared with those in the GenBank database. Based on the morphological characteristics of the strains, strain C0701 was preliminarily identified as... Ilyonectria mors-panacis Strain C0795 is *Fusarium oxysporum*, strain C0849 is *Fusarium solanum*, and strain C0872 is... Ilyonectria destructans .

[0040] 1.4 Pathogenicity determination of pathogens Fresh American ginseng rootlets were collected, disinfected with 75% ethanol, and punctured with an inoculation needle. A 4 mm diameter mycelial cake was then taken from each of the four pathogenic strains obtained in section 1.2 of Example 1 and inoculated onto the punctured site. Simultaneously, blank PDA medium was inoculated as a control. Each treatment was repeated six times. The treated ginseng roots were placed on sterile filter paper containing culture dishes for moisturizing and incubated at 25°C. Results were observed after 5-10 days, and lesions and disease progression were recorded.

[0041] The results showed that, compared with the control sample that was not inoculated, all four tested pathogenic fungi could cause disease in the detached roots of American ginseng, resulting in obvious lesions, proving that these four fungi were the pathogens of root rot in American ginseng.

[0042] Example 2: Separation and Screening of Ba25 2.1 Materials Rhizosphere soil of a four-year-old American ginseng plant collected on November 18, 2023, from Wendeng District, Weihai City, Shandong Province.

[0043] 2.2 Isolation of strains Bacterial isolation was performed using a serial dilution method. 10 g of rhizosphere soil from American ginseng was weighed and placed in separate Erlenmeyer flasks. 90 mL of sterile water was added, and the flasks were shaken thoroughly for 10-30 min on a shaker to obtain a concentration of 10%. -1 Prepare a soil suspension at a concentration of g / mL. Mix well and allow to stand. After standing, dilute the soil suspension with sterile water in a gradient to 10 g / mL. -4 g / mL, 10 -5 g / mL, 10 -6 Four dilutions of bacterial suspension at g / mL were prepared. 100 μL of each dilution was evenly spread onto TSA (Tryptic Soy Agar) agar plates, with 100 μL of sterile water as a blank control. Each concentration gradient was repeated three times. The plates were incubated at 25°C inverted. After colonies grew, they were classified according to size, color, surface, and edge characteristics. Colonies of each class were randomly selected proportionally for streak purification until uniform single colonies appeared. These were then inoculated into TSB (Tryptic Soy Broth) agar and stored in 25% glycerol for later use.

[0044] 2.3 Screening of strains Eight candidate biocontrol bacteria were isolated from the rhizosphere soil of American ginseng, and numbered Ba1, Ba20, Ba25, Ba27, Ba38, Ba79, Ba138, and Ba171. The antibacterial effects of the candidate biocontrol bacteria on the four American ginseng root rot pathogens (C0701, C0795, C0849, and C0872) verified in Example 1 were determined using the plate confrontation method to screen for biocontrol bacteria. The pathogen strains C0701, C0795, C0849, and C0872 obtained in Example 1 were activated on PDA plates and incubated in the dark at 25°C for 7 days. Mycelial cakes were then collected from the edge of the pathogen colonies using a 6mm diameter punch and inoculated into the center of a new PDA plate. Simultaneously, 2μL of the biocontrol bacterial solution was spot-inoculated 2 mm from the center of the pathogen cake. The control was PDA medium containing only pathogen cakes. Each group had three replicates. Invert the plate and incubate until the control pathogen colonies reach 3 / 4 of the plate's height. Measure the inhibition radius and calculate the inhibition rate. Inhibition rate (%) = (Control group colony diameter - Treatment group colony diameter) / Control group colony diameter × 100%.

[0045] Eight bacterial strains were initially screened for their antibacterial activity against four pathogenic bacteria. The screening criterion was an inhibition rate ≥50% against all pathogens. Based on the principle of optimal overall inhibition rate, strain Ba25 was selected as the target strain from the qualified strains. The results of the plate confrontation experiment are shown in Table 1. Table 1 shows that strain Ba25 exhibited certain antagonistic activity against the four pathogenic bacteria causing root rot in American ginseng (C0701, C0795, C0849, and C0872), with inhibition rates of 72.17%, 65.81%, 61.76%, and 69.88%, respectively, with an average inhibition rate of 67.41%. Strain Ba25 showed the best antibacterial effect against these four pathogenic bacteria among all tested strains. This indicates that this strain has broad-spectrum antagonistic characteristics against the pathogenic bacteria causing root rot in American ginseng.

[0046] Table 1. Antimicrobial effects of different strains on four pathogens causing root rot in American ginseng.

[0047] 2.4 Identification of strain Ba25 2.4.1 Morphological identification Straw strain Ba25 was streaked on TSA medium plates and incubated in the dark at 25°C for 2 days. The morphological characteristics of the colonies were observed and recorded.

[0048] The results showed that after streaking the strain Ba25 on TSA medium plates and incubating it in the dark at 25°C for 2 days, the colonies of strain Ba25 were light yellow with irregular edges, raised and wrinkled surfaces, and opaque texture.

[0049] 2.4.2 Molecular biological identification Colony PCR was used to identify strain Ba25. Primers 27F (5'-AGAGTTTGATCCTGGCTCAG-3') and 1492R (5'-TACGGCTACCTTGTTACGACTT-3') were used for 16S rDNA PCR amplification of strain Ba25. The PCR reaction system consisted of 8.5 μL ddH2O, 1 μL ITS1F, 1 μL ITS4, 12.5 μL Taq enzyme, and 2 μL DNA template, with a total reaction volume of 25 μL. PCR cycling was as follows: 95℃ pre-denaturation for 5 min, 1 cycle; 94℃ denaturation for 1 min, 52℃ annealing for 50 s, 72℃ extension for 1 min, 35 cycles; and a final extension at 72℃ for 7 min. The amplified products were sent to Suzhou Genewiz Biotechnology Co., Ltd. for sequencing. BLAST alignment of the sequences in the National Center for Biotechnology Information (NCBI) database was performed, and the taxonomic position of strain Ba25 was determined based on morphological characteristics.

[0050] The 16S rRNA gene sequence of strain Ba25 is shown in SEQ ID NO: 1. Sequence comparison analysis revealed that strain Ba25, when compared with strains in the GenBank database, was preliminarily identified as *Bacillus belye*. Bacillus velezensis ).

[0051] Example 3. Growth-promoting characteristics of strain Ba25 In this embodiment, the growth-promoting properties of Bacillus belysae strain Ba25 were verified.

[0052] Nitrogen fixation: The antagonistic bacteria were inoculated onto Assumption solid medium and cultured at 30°C for 3 days. If the strain grew normally on the solid medium, it indicated that the strain had nitrogen fixation ability.

[0053] Phosphorus solubilization: Inoculate the antagonistic strain onto an inorganic phosphorus-containing bacterial culture medium and incubate at 30°C for 5–7 days. If a transparent phosphorus-solubilizing zone appears around the colony, it indicates that the strain has the ability to dissolve inorganic phosphorus. The strength of the phosphorus-solubilizing ability can be judged based on the diameter of the phosphorus-solubilizing zone.

[0054] Phosphorus solubilization: Inoculate the strain into an organophosphate bacteria culture medium and incubate at 30°C for 5–7 days. Observe whether a clear zone appears around the colony to determine its phosphorus solubilization ability.

[0055] Indoleacetic acid (IAA) production: Strain Ba25 was inoculated onto TSA medium. After single colonies grew, they were picked and transferred to TSB medium, then incubated in a constant temperature shaker (28 ℃, 180 r / min) for 24 h to prepare a bacterial suspension. 10 μL of the bacterial suspension was inoculated into TSB (Tryptic Soy Broth) medium containing 100 mg / L L-tryptophan and incubated at 28 ℃, 180 r / min for 4 days with shaking. 200 μL of the bacterial suspension was mixed with an equal volume of Salkowski colorimetric solution, and an indoleacetic acid standard solution was prepared as a control. The solution was incubated at room temperature in the dark for 30 min. If the solution turned pink, it indicated that the strain had the ability to produce indoleacetic acid.

[0056] Ammonia production: Strain Ba25 was inoculated onto TSA medium. After single colonies grew, they were picked and transferred to TSB medium. The culture was then incubated in a constant temperature shaker (28℃, 180 r / min) for 24 h to prepare a bacterial suspension. 50 μL of the suspension was inoculated into a test tube containing 10 mL of peptone water medium. After shaking and incubating at 30℃ for 48 h, 0.5 mL of Nessler solvent was added. The color changed from yellow to reddish-brown, and a precipitate formed, indicating that the strain possessed ammonia-producing ability.

[0057] The results are as follows Figure 5 As shown.

[0058] Depend on Figure 5 As shown in A, strain Ba25 can grow slowly on Assumption solid medium, indicating that strain Ba25 has a certain nitrogen-fixing function but low activity.

[0059] Depend on Figure 5 As shown in B, strain Ba25 did not produce a phosphate-solubilizing zone after 5 days of culture on an inorganic phosphorus-free bacterial culture medium, indicating that strain Ba25 does not have phosphate-solubilizing function.

[0060] Depend on Figure 5 As shown in C, after culturing strain Ba25 on an organophosphate bacteria culture medium for 5 days, strain Ba25 did not produce a clear zone, indicating that strain Ba25 does not have phosphorus solubilization function.

[0061] Depend on Figure 5 As shown in D, strain Ba25 did not show a significant pink reaction; its color was similar to the negative control, appearing pale yellow, indicating that strain Ba25 did not exhibit significant IAA synthesis ability under the current culture conditions.

[0062] Depend on Figure 5 E indicates that after strain Ba25 was cultured in peptone water medium for 48 hours, the addition of Nessler's reagent showed that the reaction solution of the Ba25 inoculated group changed from yellow to reddish-brown, indicating that Ba25 has a strong ammonia production capacity.

[0063] Example 3. Biocontrol characteristics of strain Ba25 In this embodiment, the biocontrol characteristics of strain Ba25 were tested.

[0064] Siderophore production: Inoculate strain Ba25 into the center of the siderophore detection medium and incubate at 30℃ for 5-7 days. If an orange-yellow halo appears around the strain, it indicates that it has the ability to produce siderophores. The siderophore production ability of antagonistic strains can be judged based on the size of the halo.

[0065] Protease production: Inoculate strain Ba25 onto protease-producing medium and incubate at 30°C for 5–7 days. If a clear zone or a distinct lysis zone appears around the colony, it indicates that the strain has the ability to secrete protease; the larger the zone, the stronger the enzyme activity.

[0066] Cellulase production: Inoculate strain Ba25 in the center of a cellulose Congo red medium and incubate at 30°C for 5–7 days. If a clear halo appears around the colony, it indicates that the strain has the ability to produce cellulase.

[0067] The results are as follows Figure 6 As shown.

[0068] Depend on Figure 6 As shown in A, after culturing strain Ba25 on the siderophore detection medium for 5 days, strain Ba25 did not produce a distinct orange-yellow halo, indicating that Ba25 does not have siderophore-producing activity.

[0069] Depend on Figure 6 As shown in B, after strain Ba25 was cultured on the protease detection medium for 5 days, a transparent halo appeared around the strain, indicating that strain Ba25 has the ability to produce protease.

[0070] Depend on Figure 6 As shown in C, strain Ba25 did not produce a clear zone after being cultured on cellulose Congo red medium for 5 days, indicating that strain Ba25 does not have the ability to produce cellulase.

Claims

1. Bacillus belye ( Bacillus velezensis strain Ba25, characterized in that, The preservation number of the strain Ba25 is CGMCC NO. 38979.

2. The Bacillus belyssus strain Ba25 according to claim 1, characterized in that, The 16S rRNA gene sequence of strain Ba25 is shown in SEQ ID NO:

1.

3. The Bacillus belyssus strain Ba25 according to claim 1, characterized in that, The strain Ba25 was streaked on a TSA medium plate and incubated in the dark at 25°C for 2 days. The colonies were light yellow with irregular edges, raised and wrinkled surfaces, and opaque texture.

4. A microbial preparation comprising the Bacillus berberis strain Ba25 as described in claim 1.

5. A microbial fertilizer comprising the Bacillus berberis strain Ba25 as described in claim 1 or the microbial preparation as described in claim 4.

6. A method for inhibiting root rot in American ginseng, characterized in that, This includes applying the Bacillus berberis strain Ba25 of claim 1, the microbial preparation of claim 4, or the microbial fertilizer of claim 5 to American ginseng.

7. The method according to claim 6, characterized in that, The root rot of American ginseng is caused by Fusarium ( ). Fusarium ) fungi or genus *Solanum* ( Ilyonectria Caused by fungi.

8. A method for promoting plant growth, characterized in that, This includes applying the Bacillus berberis strain Ba25 of claim 1, the microbial preparation of claim 4, or the microbial fertilizer of claim 5 to plants.

9. The method according to claim 8, characterized in that, The plant in question is American ginseng.

10. The use of the Bacillus berberis strain Ba25 of claim 1, the microbial preparation of claim 4, or the microbial fertilizer of claim 5 in the following: 1) Inhibit root rot in American ginseng; 2) Prepare microbial agents for inhibiting root rot in American ginseng; 3) Fix nitrogen; 4) Produce ammonia; 5) Produce protease.

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