Bacillus velezensis B127 and application thereof

Abstract

The invention discloses bacillus velezensis B127 and application thereof, the bacillus velezensis is preserved in China Center for Type Microbiological Culture Collection, the preservation number is CCTCC NO: M 20252878, the preservation date is December 15, 2025, the classification name is bacillus velezensis B127, and the preservation address is Wuhan University, Hubei Province. The bacillus velezensis B127 has a remarkable inhibition effect on various tobacco fusarium pathogenic bacteria, has good phosphorus and potassium solubilizing capacity, generates hydrolase related to inhibition of pathogenic bacteria and generates siderophore and indoleacetic acid for promoting plant growth, is a biocontrol bacterium with excellent comprehensive performance, and can be widely applied to the field of biological control. The method has good development and application prospects in the fields of agricultural disease control, soil improvement, microbial fertilizers and the like.

Description

Technical Field

[0001] This invention belongs to the field of microbial technology, specifically relating to Bacillus belye B127 and its applications. Background Technology

[0002] Tobacco Fusarium root rot is caused by the genus Fusarium (… Fusarium Bacillus spp. is a significant soil-borne disease caused by fungi, seriously threatening tobacco yield and quality. Traditional chemical control methods suffer from problems such as pesticide residues, environmental pollution, and pathogen resistance, while biological control has become a research hotspot due to its high efficiency, environmental friendliness, and sustainability. Bacillus Due to its advantages such as strong sporulation resistance, secretion of antibacterial substances, and growth-promoting effects, it is widely used in the control of plant diseases. Currently, further research is needed on the screening of biocontrol strains and the mechanisms of biocontrol against tobacco Fusarium root rot. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a Bacillus belyssus B127 and its application, solving problems such as insufficient resources of biocontrol strains for Fusarium root rot in tobacco, unsatisfactory strain activity, and unstable application effects.

[0004] The technical solution provided by this invention is as follows:

[0005] This invention provides a Bacillus belye Bacillus velezensis B127, the described *Bacillus belyes*, is deposited at the China Center for Type Culture Collection (CCTCC) with accession number CCTCC NO: M 20252878, on December 15, 2025, and is classified as *Bacillus belyes*. Bacillus velezensis B127, deposited at Wuhan University, Hubei Province.

[0006] This invention also provides the use of the above-described Bacillus belyssus B127 in any of the following: (A1) Inhibits Fusarium oxysporum; (A2) Prepare a product for inhibiting Fusarium oxysporum; (A3) Control of rhizopus diseases caused by Fusarium oxysporum; (A4) Prepare products for the prevention and control of rhizopus diseases caused by Fusarium oxysporum.

[0007] The present invention also provides a method for preventing and / or treating rhizopus disease caused by Fusarium oxysporum, the method comprising applying the above-described Bacillus belesiensis B127 to tobacco.

[0008] This invention also provides the use of the above-described Bacillus belyssus B127 in any of the following: (B1) Promotes tobacco growth and development; (B2) Prepare products for promoting the growth and development of tobacco.

[0009] Furthermore, the promotion of tobacco growth includes increasing root activity, plant height, and stem diameter.

[0010] This invention also provides the use of the above-described Bacillus belyssus B127 in any of the following: (C1) Production of IAA and / or ferrocarriers; (C2) Prepare products for the production of IAA and / or ferrocarriers; (C3) Application in the breakdown of starch and / or protein; (C4) Application in the preparation of products that break down proteins and / or starches; (C5) Applications in phosphorus solubilization and / or potassium solubilization; (C6) Application in the preparation of products that can solubilize phosphorus and / or potassium.

[0011] The present invention also provides a microbial agent comprising a bacterial suspension of Bacillus belye B127 as described above, wherein the bacterial concentration in the bacterial suspension is 1 × 10⁻⁶. 7 ~1×10 9 CFU / mL.

[0012] The present invention also provides a method for preparing a microbial agent, wherein the above-mentioned Bacillus belye B127 is inoculated into a fermentation medium for fermentation culture to obtain a microbial agent.

[0013] Furthermore, the fermentation culture temperature was 28~40℃, the rotation speed was 180~220 rpm, and the time was 72~90 h.

[0014] The present invention also provides a method for promoting tobacco growth, which involves applying the above-mentioned microbial agent to the roots of tobacco plants.

[0015] Beneficial effects

[0016] The strain B127 of this invention has a significant inhibitory effect on various Fusarium oxysporum pathogens, especially on... F. grasses The inhibition rate reached 33.79%; by producing protease, phosphatase, IAA and other substances, it significantly improved the growth vigor of tobacco plants, and the control effect was better than single chemical control, with no pesticide residue risk, making it suitable for sustainable green agriculture; pot experiments showed that it could significantly reduce the incidence of Fusarium oxysporum (69.44%→0%) and disease index (74.43→28.11), with a control efficacy of 61.72%, and also had a growth-promoting effect. LCMS analysis detected 36 major components (≥0.5%), the top three of which were: C 53 H99 NO6, molecular weight 845.7476, accounting for 16.47%; C 24 H 44 N4O4, molecular weight 452.3364, accounting for 7.89%; C 55 H 103 NO6, with a molecular weight of 873.7782, accounts for 6.42%. This invention provides a highly efficient strain and technical support for the biological control of tobacco Fusarium root rot. Attached Figure Description

[0017] Figure 1 The colony morphology (A) and single colony morphology (B) of strain B127 on NA medium are shown.

[0018] Figure 2 This is a phylogenetic tree analysis of strain B127 based on 16S rDNA;

[0019] Figure 3 The antibacterial effect of strain B127 on Fusarium oxysporum (plate confrontation).

[0020] Figure 4 This describes the control effect of strain B127 on Fusarium root rot in potted tobacco. Detailed Implementation

[0021] To better understand the technical solution of this application, the above technical solution will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Unless otherwise specified, the instruments and equipment involved in the following embodiments are all conventional instruments and equipment; unless otherwise specified, the reagents and culture media involved are all commercially available conventional reagents and culture media; unless otherwise specified, the experimental methods involved are all conventional methods.

[0023] Example 1: Isolation and Identification of Strain B127

[0024] 1. Strains Isolation

[0025] Soil samples from the rhizosphere of tobacco plants in western Hunan Province were collected and placed in a 55°C oven overnight to reduce interference from other microorganisms. Subsequently, the soil samples were diluted to appropriate concentrations using a serial dilution method, spread onto NA (nutrient agar) plates, and incubated at 30°C for approximately 48 hours. Single colonies exhibiting typical Bacillus morphology were selected and purified through multiple streak platings to obtain a pure culture strain, named B127.

[0026] 2. Morphological observation

[0027] The purified strain B127 was inoculated into NA medium and cultured at 30°C for 24 hours. Colony morphology was observed and recorded. Simultaneously, the strain was stained using Gram staining, and cell morphology and staining characteristics were observed under a light microscope. The results showed that strain B127 was a Gram-positive bacillus, with round colonies, regular edges, smooth surfaces, and a milky-white color, exhibiting typical Bacillus morphological characteristics. Figure 1 ).

[0028] 3. Physiological and biochemical identification

[0029] Following the identification methods in the *Handbook of Systematic Identification of Common Bacteria*, strain B127 underwent multiple physiological and biochemical characterization tests, including sugar fermentation test, VP test, methyl red (MR) test, gelatin liquefaction test, and starch hydrolysis test. The results of these tests are detailed in Table 1. Comprehensive analysis indicates that the physiological and biochemical characteristics of strain B127 are similar to those of *Bacillus belye* (…). Bacillus velezensis They are highly consistent.

[0030] Table 1. Physiological and biochemical characteristics of strain B127

[0031]

[0032] 4. Molecular biological identification

[0033] Genomic DNA was extracted from strain B127 using a bacterial genomic DNA extraction kit. The 16S rDNA sequence was amplified using universal primers 27F (5′-AGAGTTTGATCMTGGCTCAG-3′ (SEQ ID NO.2)) and 1492R (5′-TACGGYTACCTTGTTACGACTT-3′ (SEQ ID NO.3)). PCR system: 35 μL; PCR conditions: 98℃, 5 min; 98℃, 25 s, 56℃, 25 s, 72℃, 55 s, 34 cycles; 72℃, 10 min, 4℃, 2 min. The PCR product was purified and sent to Changsha Qingke Biotechnology for sequencing (SEQ ID NO.1). The obtained sequence was analyzed by BLAST comparison using the NCBI database. A phylogenetic tree was constructed based on the neighbor-joining method. The results showed that strain B127 is related to Bacillus belye (…). Bacillus velezensis The standard strains clustered into the same evolutionary branch, with sequence similarity exceeding 99%, ultimately identifying strain B127 as *Bacillus belyes*. Bacillus velezensis () Figure 2 This strain Bacillus velezensisB127 was deposited at the China Center for Type Culture Collection on December 15, 2025, with accession number CCTCC NO:M 20252878. The deposit address is located at No. 299 Bayi Road, Wuchang District, Wuhan City, Hubei Province, inside Wuhan University (opposite to the First Affiliated Primary School of Wuhan University).

[0034] Example 2: Determination of antibacterial activity

[0035] To evaluate Bacillus belesiensis ( Bacillus velezensis The inhibitory potential of B127 fermentation broth against the main pathogenic Fusarium moniliforme in tobacco was determined by plate confrontation method, which was used to determine its antagonistic activity against eight Fusarium species.

[0036] Preparation of B127 fermentation broth: Glycerol tubes of the preserved B127 strain were streaked onto LB solid medium for activation. After incubation at 37℃ for 24 h, a single colony was picked and inoculated into 5 mL of LB liquid medium. The culture was then incubated at 37℃ and 200 r / min with shaking for 12 h to prepare the seed culture. The seed culture was then inoculated into fresh LB liquid medium at a 1:100 (v / v) inoculation rate and incubated at 37℃ and 200 r / min with shaking for 84 h (3.5 d). After fermentation, the culture was centrifuged at 10000 rpm for 5 min, and the supernatant was filtered through a 0.22 μm sterile filter membrane to obtain sterile B127 fermentation broth.

[0037] The specific method is as follows: After activation, the pathogenic fungal strain to be tested is used to cut a mycelial cake from the edge of the colony using an 8 mm diameter punch (or a blue pipette tip), and inoculated into the center of a PDA (potato dextrose agar) medium plate. B127 fermentation broth is inoculated at equidistant points in four directions (up, down, left, and right) at a distance of 25 mm from the center. Each treatment is repeated four times, with a blank control (no B127 fermentation broth inoculation). The plates are incubated at 28℃ for 7 days. The mycelial growth of the pathogenic fungus is observed, and the growth radius of the pathogenic fungus mycelium from the edge of the mycelial cake to the center of the B127 fermentation broth inoculation point is measured.

[0038] The antibacterial rate is calculated using the following formula: Inhibition rate (%) = (Mycelial growth radius of control group - Mycelial growth radius of treatment group) ÷ Mycelial growth radius of control group × 100%

[0039] The measurement results are as follows Figure 3 As shown in Table 4, the fermentation broth of *Bacillus belye* B127 exhibited varying degrees of inhibitory effects on all seven tested *Fusarium* species, but the inhibitory effects varied among species (18.98% - 33.79%). Specifically, the inhibitory effects on... F. grasses The disease suppression rate was the highest, reaching 33.79% ± 8.32%; while for... F. asiaticumThe inhibition rate was the lowest, at 18.98% ± 2.70%. This indicates that the fermentation broth of strain B127 has a good effect on inhibiting certain Fusarium species, but its effect on other species is relatively weak.

[0040] The above results indicate that strain B127 has broad-spectrum antibacterial activity against various Fusarium species, especially against... F. proliferated and F. graminearum The inhibitory effect was quite significant, demonstrating its potential as a biological control strain. These results provide laboratory evidence for the application of strain B127 in the control of tobacco Fusarium root rot, but its field control efficacy, stability, and environmental adaptability still require further verification.

[0041] Table 2. Inhibition rate of strain B127 fermentation broth against Fusarium wilt (plate confrontation)

[0042]

[0043] Example 3: Determination of biocontrol characteristics of strain B127

[0044] To systematically evaluate Bacillus belesiensis ( Bacillus velezensis To assess the biocontrol potential of strain B127, this example determined several key physiological characteristics related to its biocontrol functions. The specific methods are as follows: 2 μL of the activated fermentation broth of strain B127 from Example 2 was inoculated into the center of specific functional test media for protease, phosphatase, amylase, chitinase, cellulase, phosphorus solubilization, potassium solubilization, nitrogen fixation, siderophore production, and IAA production. Each test was performed in triplicate to ensure the reliability of the results. The inoculated plates were placed in a 28°C incubator for 7 days, and the formation of a clear zone or other characteristic reactions around the colonies was observed periodically. If a clear zone or color reaction appeared in the culture medium, it was considered positive (+), indicating that the strain possessed the corresponding function; if no significant change was observed, it was considered negative (-). The results are shown in Table 3.

[0045] Table 3 Biocontrol characteristics of Bacillus belyssus B127

[0046]

[0047] As shown in Table 3, after 7 days of culture, strain B127 showed positive results in all tests, including protease, phosphatase, amylase, phosphorus solubilization, potassium solubilization, siderophore production, and IAA production. This indicates that it has the ability to secrete a variety of hydrolases, dissolve inorganic phosphorus and potassium, synthesize siderophores, and synthesize indoleacetic acid (IAA).

[0048] These functional characteristics play an important role in plant disease control and growth promotion: (i) the secretion of proteases, amylases and phosphatases can participate in the degradation of pathogenic fungal cell wall components or organophosphorus compounds, inhibiting their infection and spread; (ii) the ability to solubilize phosphorus and potassium helps to improve the bioavailability of insoluble phosphorus and potassium in the soil, promoting crop nutrient absorption and growth; (iii) the production of siderophores can chelate iron ions in the environment, limiting the pathogen's acquisition of iron through competitive inhibition, thereby inhibiting its reproduction; (iv) the ability to produce IAA indicates that the strain can synthesize plant growth hormones, which helps to stimulate root development and enhance the host plant's resistance and colonization ability.

[0049] However, strain B127 tested negative for chitinase, cellulase, and nitrogen fixation, indicating that it lacks the ability to degrade chitin or cellulose and has no autonomous nitrogen fixation function. Despite lacking the ability to directly degrade the main component of fungal cell walls (chitin), it still exhibits strong comprehensive biocontrol potential through the synergistic effect of various other mechanisms.

[0050] In summary, although strain B127 does not possess all biocontrol-related traits, it demonstrates outstanding performance in enzyme production, phosphorus and potassium solubilization, siderophore synthesis, and plant growth promotion, thus possessing the core functional basis for use as a biocontrol agent. These results further validate its promising application prospects in the control of tobacco Fusarium root rot and provide important experimental evidence for its subsequent development into an environmentally friendly biopesticide.

[0051] Example 4: Verification of the disease prevention effect of potted plants

[0052] To verify Bacillus belesiensis ( Bacillus velezensis To investigate the control effect of B127 on tobacco Fusarium root rot and its promoting effect on tobacco growth, a pot experiment was conducted to systematically evaluate the disease incidence and agronomic traits of tobacco under different treatment conditions.

[0053] Preparation of Bacillus belye B127 bacterial suspension: The activated strain was inoculated into LB liquid medium and cultured at 37℃ and 200 r / min for 84 h (3.5 d) with shaking. The bacterial suspension concentration was adjusted to 1×10⁻⁶ with sterile water. 8 CFU / mL available for use.

[0054] The specific procedures for the pot experiment were as follows: Four-leaf tobacco seedlings (Yunyan 87 variety) were transplanted into pots with a diameter of 11 cm and a height of 9 cm, each containing 200 g of cultivation substrate. Ten pots were used for each treatment. A 14h / 10h light / dark treatment was applied, with a light intensity of 6000 lx. After 7 days of greenhouse cultivation, inoculation with the pathogen and a suspension of Bacillus belyssus B127 was initiated. The pathogen was inoculated first (spore suspension 1×10⁻⁶). 820 mL of spore / mL was inoculated, followed by inoculation with Bacillus belye B127 (1 × 10⁻⁶ bacterial suspension). 8 CFU / mL * 20mL). The specific inoculation method is as follows: Inoculate the bacterial suspension (1×10... 8 The inoculated tobacco seedlings were filled with sterile water (20 mL) and then evenly applied to the root soil, with each seedling receiving 20 mL of sterile water as a control. Specific treatments are shown in Table 4. The inoculated tobacco seedlings were then placed in a greenhouse for further cultivation, managed in the same way as normal cultivation. After 21 days of cultivation, the incidence of tobacco root rot was assessed.

[0055] 1. Experimental Design:

[0056] The experiment consisted of four treatment groups, with three replicates in each group. The specific treatments are as follows (Table 4):

[0057] Table 4 Pot Experiment Treatments

[0058]

[0059] 2. Evaluation of the effectiveness of disease prevention and control

[0060] Twenty-one days after vaccination, the incidence and disease index of each treatment group were statistically analyzed, and the results are shown in Table 5.

[0061] Table 5. Incidence rate and disease index of each treatment group in the pot experiment.

[0062]

[0063] Table 5 shows that the incidence rate in group G2 (inoculated with the pathogen only) was as high as 97.22%, and the disease index was 73.43, significantly higher than other treatment groups (P<0.05), indicating that Fusarium is highly pathogenic to tobacco. In contrast, the incidence rate and disease index in group G3 (inoculated with B127 first, then with the pathogen) decreased to 69.44% and 28.11, respectively, significantly lower than group G2 (P<0.05), indicating that Bacillus belycei B127 can effectively alleviate the symptoms of root rot caused by Fusarium and has a significant disease prevention effect. No disease was observed in groups G1 and G4, indicating that B127 itself is not pathogenic to tobacco and does not induce abnormal reactions under the absence of pathogen stress.

[0064] 3. Agronomic trait determination and analysis

[0065] Meanwhile, agronomic traits such as plant height, stem circumference, biomass, and fresh weight of aboveground / underground parts of tobacco in each treatment group were measured, and the results are shown in Table 6.

[0066] Table 6. Agronomic traits of tobacco plants after 21 days in pots

[0067]

[0068] Agronomic trait analysis showed that: a. Plant height: Group G4 had the highest height (12.53 cm), which was significantly higher than other groups (P<0.05), while Group G2 had the lowest height (5.70 cm), indicating that the pathogen severely inhibited growth, while B127 had a significant growth-promoting effect; b. Biomass fresh weight and aboveground fresh weight: Group G4 was significantly higher than other treatment groups, indicating that B127 can effectively promote the overall growth of tobacco. c. Stem circumference: Group G4 had the largest (3.10 cm), which was significantly better than Group G2, reflecting an improvement in plant vigor; d. Fresh weight of underground parts: Group G3 had the highest weight (3.33 g), which was significantly higher than Group G2 (0.74 g), indicating that B127 can still promote root development and enhance stress resistance under pathogen stress.

[0069] 4. Comprehensive Analysis and Conclusion

[0070] The comprehensive data on disease control and agronomic traits show that: (1) Bacillus belye B127 has a significant control effect on Fusarium root rot of tobacco, which can reduce the disease index to 38.3% of the control group; (2) B127 itself is safe and harmless to tobacco, and can still significantly promote plant height, biomass, stem circumference and aboveground growth under pathogen-free conditions, demonstrating its good plant growth-promoting ability. (3) Under pathogen stress, pre-inoculation with B127 can effectively alleviate the inhibition of root and aboveground growth by the disease, and in particular significantly increase the biomass of the underground parts, which helps to maintain plant vigor; (4) Comparing groups G1 and G4, it was confirmed that the growth-promoting effect of B127 is independent of disease control and has the potential to directly promote tobacco growth.

[0071] Therefore, Bacillus belye B127 not only has the ability to inhibit Fusarium infection, but also improves tobacco growth through multiple pathways, possessing both "disease prevention" and "growth promotion" functions, making it a biological control strain with great application prospects.

[0072] Example 5: Identification of active ingredients in the fermentation broth of the strain

[0073] To clarify the identity of Bacillus belysinus ( Bacillus velezensis This study investigates the composition of active substances produced by strain B127 during its growth and metabolism, revealing its potential antibacterial and growth-promoting mechanisms. In this embodiment, the active components of the fermentation broth of strain B127 were systematically identified. The specific steps are as follows:

[0074] 1. Preparation of fermentation broth

[0075] The preserved B127 strain glycerol tubes were streaked onto LB solid medium for activation. After incubation at 37°C for 24 h, a single colony was picked and inoculated into 5 mL of LB liquid medium. The culture was then incubated at 37°C with shaking at 200 rpm for 12 h to prepare the seed culture. The seed culture was then inoculated into fresh LB liquid medium at a 1:100 (v / v) inoculation rate and incubated at 37°C with shaking at 200 rpm for 84 h (3.5 d). After fermentation, the culture was centrifuged at 10,000 rpm for 5 min, and the supernatant was filtered through a 0.22 μm sterile filter to obtain sterile fermentation filtrate for subsequent chemical composition analysis.

[0076] 2. High-performance liquid chromatography-mass spectrometry (LC-MS) analysis

[0077] High-performance liquid chromatography-mass spectrometry (HPLC-MS) was used for qualitative and quantitative analysis of the active components in the fermentation filtrate of B127. The chromatographic conditions were as follows: a Kromasil ODS reversed-phase column (4.6 mm × 250 mm, 5 μm); mobile phase: acetonitrile (A) and water (B), with a gradient elution program: 0–20 min, 10% A → 80% A; 20.01–30 min, 80% A → 100% A; 30.01–40 min, 100% A; flow rate: 1.0 mL / min; column temperature: 25℃; detection wavelength: 254 nm. High-resolution mass spectrometry (HRMS) was used for molecular weight determination, and the structures of the major components were analyzed by combining ¹H NMR and ¹³C NMR spectra.

[0078] 3. Results of active ingredient analysis

[0079] LC-MS analysis identified 36 compounds with an abundance ≥0.5%, with molecular weights ranging from 148.016 to 1035.6838 Da and retention times (RT) ranging from 2.884 to 41.672 min. The total volume percentage of the 36 main active substances was 74.66%, indicating that they were the main metabolites in the fermentation broth.

[0080] Table 7. LCMS Detection Table of Active Substances in Bacillus belyssus B127 Fermentation Broth (Abundance ≥ 0.5%)

[0081]

[0082] 4. Preliminary analysis of component functions

[0083] Based on comparison with existing literature, the molecular formula is C. 24 H 44The N4O4 compound may be a cyclic dipeptide (diketopiperazine) derivative, possessing certain antifungal and signal-regulating activities; while C 53 H 99 NO6 and C 55 H 103 High molecular weight nitrogen-containing compounds such as NO6 likely belong to the lipopeptide antibiotic class (e.g., the fengycin or iturin family) or their derivatives. These substances have been shown to inhibit various plant pathogenic fungi. Considering the strong inhibitory activity of this strain against Fusarium, it is speculated that its disease-preventing mechanism may be closely related to these lipopeptide metabolites.

[0084] 5. Summary

[0085] This embodiment used LC-MS technology to systematically identify the main active metabolites in the fermentation broth of *Bacillus belyssiensis* B127, clarifying its chemical diversity and structural characteristics of dominant components. The results show that B127 can produce a variety of potentially bioactive secondary metabolites, especially rich in lipopeptides and cyclic dipeptides that may have antifungal activity, providing an important chemical basis and theoretical support for its mechanism of action in controlling *Fusarium oxysporum* root rot in tobacco. These results further support the development potential of B127 as a novel microbial pesticide.

[0086] 16S rDNA sequence (SEQ ID NO.1): (1438bp)

[0087] Information on the preservation of biological materials: strain Bacillus velezensis B127 was deposited at the China Center for Type Culture Collection on December 15, 2025, with accession number CCTCC NO:M 20252878. The deposit address is located at No. 299 Bayi Road, Wuchang District, Wuhan City, Hubei Province, on the campus of Wuhan University (opposite to the First Affiliated Primary School of Wuhan University).

Claims

1. A strain of Bacillus belye Bacillus velezensis B127, characterized in that, The described *Bacillus belyssus* is deposited at the China Center for Type Culture Collection (CCTCC) with accession number CCTCC NO: M 20252878, on December 15, 2025, and is classified as *Bacillus belyssus*. Bacillus velezensis B127, deposited at Wuhan University, Hubei Province.

2. The use of Bacillus belyssus B127 according to claim 1 in any of the following: (A1) Inhibits Fusarium oxysporum; (A2) Prepare a product for inhibiting Fusarium oxysporum; (A3) Control of rhizopus diseases caused by Fusarium oxysporum; (A4) Prepare products for the prevention and control of rhizopus diseases caused by Fusarium oxysporum.

3. A method for preventing and / or treating rhizopus disease caused by Fusarium oxysporum, characterized in that, The method includes applying the Belize B127 of claim 1 to tobacco.

4. The use of Bacillus belyssus B127 according to claim 1 in any of the following: (B1) Promotes tobacco growth and development; (B2) Prepare products for promoting the growth and development of tobacco.

5. The application according to claim 4, characterized in that, The promotion of tobacco growth includes improving root vitality, increasing plant height and stem diameter.

6. The use of Bacillus belyssus B127 according to claim 1 in any of the following: (C1) Production of IAA and / or ferrocarriers; (C2) Prepare products for the production of IAA and / or ferrocarriers; (C3) Application in the breakdown of starch and / or protein; (C4) Application in the preparation of products that break down proteins and / or starches; (C5) Applications in phosphorus solubilization and / or potassium solubilization; (C6) Application in the preparation of products that can solubilize phosphorus and / or potassium.

7. A microbial inoculant, characterized in that, The microbial agent comprises a bacterial suspension of Bacillus belye B127 as described in claim 1, wherein the bacterial concentration in the bacterial suspension is 1 × 10⁻⁶. 7 ~1×10 9 CFU / mL.

8. A method for preparing a microbial inoculant, characterized in that, The Bacillus berreatus B127 of claim 1 is inoculated into a fermentation medium for fermentation culture to obtain a microbial agent.

9. The method for preparing the microbial inoculant according to claim 8, characterized in that, The fermentation culture temperature was 28~40℃, the rotation speed was 180~220 rpm, and the time was 72~90 h.

10. A method for promoting tobacco growth, characterized in that, The microbial agent described in claim 7 was used to treat the roots of tobacco plants by drenching.

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