Paenibacillus-like strain fhyl and application thereof

Abstract

This invention discloses a strain of Bacillus subtilis FHY1 and its applications, belonging to the field of microbiology. The present invention obtained a strain of Bacillus subtilis FHY1 from the juice of Populus euphratica in Xinjiang. Experimental verification shows that the liquid culture of the Bacillus subtilis FHY1 strain provided by this invention has a significant inhibitory effect on rice blast fungus, with an inhibition rate of 84% and an inhibition rate of 92% on rice blast fungus spore germination. It can promote rice growth under conditions of 150mM NaCl and 250mM NaCl. Simultaneously, this strain also has good inhibitory effects on rice blast fungus, Fusarium oxysporum, Fusarium graminearum, Sclerotinia sclerotiorum, and Anthracnose fungus. Therefore, this invention provides a new strain with good control effect against pathogenic fungi, and significantly promotes rice growth and development under salt stress.

Description

Technical Field

[0001] This invention relates to the field of microbiology, and in particular to a Bacillus subtilis strain FHY1 and its applications. Background Technology

[0002] Rice blast is a fungal disease caused by the asexual generation of *Pyrhodotorula oryzae* or the sexual generation of *Gnaphalium affine*. As one of the three major diseases of rice, it is widely distributed and can occur at all growth stages, posing a serious threat to food security. Currently, field control of this disease mainly relies on chemical pesticides. Although these can control the disease in the short term, long-term application leads to increasingly prominent problems such as pesticide residues, environmental pollution, and pathogen resistance. At the same time, soil salinization is intensifying, with the area of ​​saline-alkali land continuously expanding. Saline-alkali land significantly inhibits normal rice growth through osmotic stress and ion toxicity, further increasing the pressure on grain production. While some progress has been made in microbial control research targeting single problems, such as developing strains with biocontrol or growth-promoting functions, multifunctional microbial resources capable of simultaneously addressing rice blast and saline-alkali stress remain extremely scarce, making it difficult to meet the comprehensive needs of green and sustainable rice development.

[0003] Current technologies primarily focus on single-function microbial agents, such as strains specifically antagonistic to rice blast fungus or microorganisms with only salt tolerance and growth-promoting properties. These strains have limited functionality and cannot simultaneously address both disease and abiotic stress in rice production. This necessitates the separate application of different agents, increasing costs and management complexity, and potentially affecting control efficacy due to competition or mutual exclusion between strains. Furthermore, the complex infection process of rice blast, with conidial germination being a crucial step in pathogenicity, requires high levels of inhibitory spectrum and stress resistance from antagonistic bacteria. In contrast, the harsh environment of saline-alkali soils makes it difficult for ordinary microorganisms to colonize and exert their effects under high pressure and ion toxicity. Therefore, the lack of multifunctional strains possessing both broad-spectrum antibacterial activity and high salt tolerance is a major bottleneck hindering the coordinated development of biological control and saline-alkali soil improvement.

[0004] To address the limitations of existing technologies in terms of single-function and insufficient adaptability, the development of microbial strains capable of simultaneously antagonizing rice blast fungus and enhancing crop salt tolerance has become an urgent need. However, the discovery of such multifunctional strains faces numerous challenges: on the one hand, the strains need to possess highly efficient and broad-spectrum antibacterial capabilities, especially targeting key infection stages such as conidial germination of rice blast fungus; on the other hand, the strains also need to maintain strong survival and metabolic activity in saline-alkali environments to mitigate the effects of salt stress on crops through colonization and growth promotion. Currently, no Bacillus-like strains that simultaneously meet these requirements have been reported in existing technologies. Summary of the Invention

[0005] The purpose of this invention is to provide a strain of Bacillus subtilis FHY1 and its applications to solve the problems existing in the prior art. The liquid culture of the Bacillus subtilis FHY1 strain provided by this invention has a significant inhibitory effect on rice blast fungus, and also shows good inhibitory effects on rice blast fungus, Fusarium oxysporum, Fusarium graminearum, Sclerotinia sclerotiorum, and Bacillus anthracis. Simultaneously, this strain significantly promotes rice growth and development under salt stress.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] This invention provides a strain of Paenibacillus cathormii FHY1, which was deposited on October 16, 2025, at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 36200.

[0008] The present invention also provides a microbial inoculant, the active ingredients of which include the aforementioned Bacillus spp. FHY1 and / or its fermentation products.

[0009] The present invention also provides the application of the aforementioned Bacillus spp. FHY1 or the aforementioned microbial agent in the prevention and control of rice blast.

[0010] The present invention also provides a method for preventing and controlling rice blast disease, comprising the step of treating rice with the aforementioned Bacillus subtilis FHY1 or the aforementioned microbial agent.

[0011] The present invention also provides the application of the aforementioned Bacillus spore-forming FHY1 or the aforementioned microbial agent in inhibiting pathogens, characterized in that the pathogens include rice blast fungus, Fusarium oxysporum, Fusarium graminearum, Sclerotinia sclerotiorum, and Bacillus anthracis.

[0012] The present invention also provides the application of the aforementioned Bacillus spp. FHY1 or the aforementioned microbial agent in improving the salt resistance of rice.

[0013] Furthermore, improving the salt stress resistance of rice includes enhancing the seed germination and seedling growth capabilities of rice under salt stress.

[0014] The present invention also provides a method for improving the salt resistance of rice, comprising the step of treating rice seeds and / or seedling roots with the aforementioned Bacillus subtilis FHY1 or the aforementioned microbial agent.

[0015] Furthermore, improving rice's salt tolerance includes enhancing seed germination and / or seedling growth under salt stress.

[0016] The present invention discloses the following technical effects:

[0017] This invention obtained a Bacillus-like bacterium, FHY1, from the juice of Populus euphratica in Xinjiang. Experimental verification showed that the liquid culture of this Bacillus-like bacterium FHY1 strain significantly inhibited the growth of rice blast fungus, achieving an inhibition rate of 84% and a 92% inhibition rate on spore germination. It promoted rice growth under conditions of 150 mM NaCl and 250 mM NaCl. Simultaneously, this strain also showed good inhibitory effects against rice blast fungus, Fusarium oxysporum, Fusarium graminearum, Sclerotinia sclerotiorum, and Anthracnose. Therefore, this invention provides a novel strain with good control effects against pathogenic fungi, while significantly promoting rice growth and development under salt stress. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 The morphology of Bacillus subtilis strain FHY1;

[0020] Figure 2 This is a graph showing the results of Bacillus subtilis strain FHY1 and rice blast fungus strain confronting each other on a 28°C plate for 8 days.

[0021] Figure 3 The image shows the results of 8-day plate confrontation between Bacillus subtilis FHY1 strain and Fusarium graminearum, Sclerotinia sclerotiorum, Bacillus anthracis, and Fusarium oxysporum strains at 28°C; from left to right, the pathogens are Fusarium graminearum, Fusarium oxysporum, Sclerotinia sclerotiorum, and Bacillus anthracis.

[0022] Figure 4 The diagram shows the inhibitory effect of liquid culture of Bacillus oryzae FHY1 on spore germination of rice blast fungus strain;

[0023] Figure 5 Phenotypic diagram of rice seed germination promoted by liquid culture of Bacillus subtilis FHY1 strain;

[0024] Figure 6 Phenotypic diagram of the effect of liquid culture of Bacillus spp. FHY1 on rice growth. Detailed Implementation

[0025] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0026] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included within the scope of this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0027] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0028] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0029] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0030] Example 1: Isolation and identification of Bacillus subtilis strain FHY1

[0031] 1. Isolation of strains

[0032] Populus euphratica sap collected from Xinjiang, China, was used as the isolation source. The sap samples were serially diluted with sterile physiological saline (10⁻⁶ ppm). -1 10 -2 10 -3 10 -4 10 -5 Take 100 μL of each dilution gradient solution and spread it on the surface of LB solid medium plates. Incubate in an inverted incubator at 30°C for 24-48 h.

[0033] 2. Functional screening and purification

[0034] The colony growth on the plates was observed, and single colonies of different morphologies, sizes, and colors were selected and purified multiple times on new LB agar plates using the streak method until pure cultures were obtained. Subsequently, the plate confrontation culture method was used, and the purified bacterial strains were co-cultured with *Bacillus oryzae*, *Fusarium graminearum*, *Fusarium oxysporum*, *Sclerotinia sclerotiorum*, and *Bacillus anthracis* on PDA plates to screen for strains with significant inhibitory effects against multiple pathogens.

[0035] As a result, a bacterial strain that showed significant antagonistic effects against rice blast fungus, Fusarium graminearum, Fusarium oxysporum, Sclerotinia sclerotiorum, and anthracnose fungus was selected and named FHY1.

[0036] 3. Molecular biological identification

[0037] Genomic DNA was extracted from strain FHY1. Using this DNA as a template, PCR amplification was performed using universal primers for the bacterial 16S rRNA gene. The amplified product was sequenced to obtain the full-length 16S rRNA gene sequence, as shown in SEQ ID NO.1.

[0038] SEQ ID NO.1:

[0039]

[0040] The 16S rRNA gene sequence obtained from sequencing was submitted to the GenBank database of the National Center for Biotechnology Information (NCBI), and homology comparison was performed using its BLAST program. Simultaneously, multiple sequence alignment was performed using ClustalX software, and a phylogenetic tree was constructed using the Neighbor-Joining method in MEGA 7.07 software. Sequence alignment and phylogenetic analysis results showed that this strain shared 99.79% homology with the type strain of the genus *Paenibacillus cathormii*. Therefore, strain FHY1 was preliminarily identified as belonging to the genus *Paenibacillus cathormii*.

[0041] 4. Identification by morphological characteristics

[0042] The FHY1 strain was inoculated onto LB solid medium containing 10% (w / v) sodium chloride (NaCl) and cultured at 30°C for 8 days. Colony morphology was then observed. Figure 1 As shown, FHY1 colonies are white, round, smooth, moist, and slightly raised, and are opaque. This result indicates that the FHY1 strain has the ability to grow and metabolize in a high-salt environment.

[0043] 5. Strain identification and preservation

[0044] Based on the above-mentioned colony morphology characteristics, physiological and biochemical properties (salt tolerance) and 16S rRNA gene sequence analysis results, the FHY1 strain provided by this invention is identified as Paenibacillus cathormii, and named Paenibacillus cathormii FHY1.

[0045] This strain was deposited on October 16, 2025, at the China General Microbiological Culture Collection Center (CGMCC) of the Institute of Microbiology, Chinese Academy of Sciences, located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, China, with accession number CGMCC No. 36200.

[0046] Example 2: Plate confrontation between Bacillus subtilis strain FHY1 and rice blast fungus strain

[0047] In this embodiment, the plate confrontation culture method was used to determine the inhibitory effect of Bacillus subtilis FHY1 on Magnaporthe oryzae, the causal agent of rice blast.

[0048] The specific steps are as follows:

[0049] Pathogen preparation: The preserved rice blast fungus strain was activated and cultured on a PDA plate at 28°C for 7 days. A 5mm diameter mycelial cake was cut from the edge of the colony using a sterile punch for later use.

[0050] Preparation of antagonistic bacteria: Bacillus subtilis FHY1 was cultured in LB liquid medium at 30°C and 180 rpm for 48 h to prepare a bacterial suspension. The concentration of the bacterial suspension was adjusted to approximately 1 × 10⁻⁶ using sterile physiological saline. 8 CFU / mL.

[0051] Confrontation culture: Prepare fresh PDA plates. Place one rice blast fungus mycelium cake prepared in step 1 at the center of the plate. Then, at equal intervals along the circumference of the central mycelium cake with a radius of 2.5 cm, inoculate 5 μL of Bacillus subtilis FHY1 suspension prepared in step 2 at each inoculation point. A plate inoculated only with the rice blast fungus mycelium cake at the center without inoculating with Bacillus subtilis FHY1 suspension serves as a control group.

[0052] Culture and observation: All inoculated plates were placed in a 28℃ constant temperature incubator and cultured in the dark for 8 days.

[0053] Results: After cultivation, the colony diameter of rice blast fungus in the control and treatment groups was measured. Results are as follows: Figure 2 As shown, compared with the control group, the growth of rice blast fungus in the treatment group was significantly inhibited by the surrounding Bacillus subtilis strain FHY1. After a period of time, the mycelium stopped growing and showed obvious signs of aging. Calculations showed that Bacillus subtilis FHY1 had an inhibition rate of 85% against rice blast fungus, indicating that it has a strong antagonistic effect on this pathogen.

[0054] Example 3: Determination of the antagonistic effect of Bacillus subtilis FHY1 against various plant pathogenic fungi.

[0055] In this embodiment, the plate confrontation culture method was used to further determine the inhibitory effect of Bacillus subtilis FHY1 on Fusarium graminearum, Sclerotinia sclerotiorum, Colletotrichumspp., and Fusarium oxysporum.

[0056] The specific steps are as follows:

[0057] Pathogen preparation: Fusarium graminearum, Sclerotinia sclerotiorum, Bacillus anthracis, and Fusarium oxysporum were activated and cultured on their respective target PDA plates at 28°C for 7 days. A 5mm diameter mycelial cake was cut from the edge of each colony using a sterile punch for later use.

[0058] Preparation of antagonistic bacteria: Bacillus subtilis FHY1 was cultured in LB liquid medium at 30°C and 180 rpm for 48 h to prepare a bacterial suspension. The concentration of the bacterial suspension was adjusted to 1×10⁻⁶ using sterile physiological saline. 8 CFU / mL.

[0059] Confrontation culture: Prepare fresh PDA plates. At the center of each plate, place one *Fusarium graminearum*, *Sclerotinia sclerotiorum*, *Anthracis*, or *Fusarium oxysporum* mycelium prepared in step 1 (each pathogen has its own independent confrontation culture plate). Then, at equal intervals along a 2.5 cm radius circle centered on the central mycelium, inoculate 5 μL of *Bacillus spp. FHY1* suspension prepared in step 2 at each inoculation point. A control group was prepared by inoculating only the corresponding pathogen mycelium without inoculating the FHY1 suspension.

[0060] Culture and observation: All plates were placed in a 28℃ constant temperature incubator and cultured in the dark for 8 days.

[0061] After incubation, the colony diameter of the pathogens in each group was measured and recorded. The results are as follows: Figure 3 As shown, the Bacillus subtilis FHY1 strain exhibited varying degrees of inhibitory activity against the four tested pathogenic fungi. The calculated inhibition rates of Bacillus subtilis FHY1 against each pathogen were as follows:

[0062] The inhibition rate against Fusarium graminearum was 60%.

[0063] The inhibition rate against Sclerotinia sclerotiorum was 73%.

[0064] The inhibition rate against anthrax bacteria was 69%.

[0065] The inhibition rate against Fusarium oxysporum was 47%.

[0066] The above results indicate that Bacillus spp. FHY1 has broad-spectrum antibacterial activity and good control potential against a variety of important plant pathogenic fungi.

[0067] Example 4: Inhibitory effect of liquid culture of Bacillus subtilis strain FHY1 on spore germination of rice blast fungus strain

[0068] This embodiment uses a spore germination inhibition test to determine the direct effect of the liquid fermentation product of Bacillus subtilis FHY1 on the germination of conidia of rice blast fungus.

[0069] 1. Preparation of rice blast fungus spore liquid

[0070] The rice blast fungus strain was inoculated onto OMA solid medium plates. The OMA medium formula was: 30g of oats, 150mL of tomato juice, water to a final volume of 1L, 15g (i.e., 1.5% w / v) of agar powder, sterilized, and then poured into plates.

[0071] The inoculated plates were placed in an incubator at 28°C and incubated for 8 days.

[0072] Gently scrape the mycelium from the surface of the culture medium with a sterile cotton swab and incubate it upside down at room temperature for 2 days to induce sporulation.

[0073] Add an appropriate amount of sterile water (about 5-10 mL) to the plate, and gently scrape the surface of the culture medium with a sterile cotton swab to ensure that the conidia are fully suspended in the water.

[0074] Filter this suspension using double-layered sterile lens paper or filter paper to remove hyphal debris.

[0075] The concentration of the filtrate was adjusted using a hemocytometer under a microscope, ultimately preparing a spore concentration of 1×10⁻⁶. 5 A suspension of rice blast fungus spores per mL was prepared for later use.

[0076] 2. Preparation of liquid culture of Bacillus subtilis FHY1

[0077] Bacillus subtilis FHY1 was inoculated into LB liquid medium and cultured at 30°C with shaking at 180 rpm for 48 h to obtain a liquid culture of Bacillus subtilis FHY1. This culture can be used directly or stored briefly at 4°C for later use.

[0078] 3. Spore germination inhibition test

[0079] Treatment group: The Bacillus spore-forming liquid culture FHY1 prepared in step 2 was thoroughly mixed with the rice blast fungus spore liquid prepared in step 1 at a volume ratio of 1:1.

[0080] Control group: Equal volumes of sterile LB liquid culture medium and rice blast fungus spore liquid were mixed at a volume ratio of 1:1.

[0081] Take 50 μL of the mixture and drop it onto a sterile hydrophobic membrane.

[0082] The hydrophobic film was placed in a petri dish (as a humidified chamber) lined with moistened filter paper to maintain a relative humidity of nearly 100%.

[0083] Each process is set to 3 repetitions.

[0084] Place the humidified box in a 28°C incubator and incubate in the dark for 4 hours.

[0085] 4. Results Observation and Calculation

[0086] After cultivation, multiple fields of view were randomly observed under an optical microscope, and the germination status of at least 200 spores was recorded. Germination was defined as when the germ tube length exceeded half the spore diameter.

[0087] The results are as follows Figure 4 As shown, spore germination in the treatment group was significantly inhibited compared to the control group.

[0088] The spore germination inhibition rate is calculated using the following formula:

[0089] Germination inhibition rate (%) = [(germination rate of control group - germination rate of treatment group) / germination rate of control group] × 100%.

[0090] Calculations showed that the liquid culture of Bacillus subtilis FHY1 inhibited the germination of rice blast fungus spores by up to 92%.

[0091] This embodiment demonstrates that Bacillus spp. FHY1 can efficiently inhibit the germination of conidia of rice blast fungus through its metabolites, which is one of the key mechanisms by which it exerts its biological control effect.

[0092] Example 5: The promoting effect of Bacillus subtilis FHY1 on rice seed germination under salt stress

[0093] This embodiment verifies the alleviating effect of Bacillus subtilis FHY1 on rice seed germination under salt stress through a seed germination experiment.

[0094] 1. Preparation of bacterial suspension and solution

[0095] Preparation of Bacillus subtilis FHY1 bacterial suspension: Bacillus subtilis FHY1 was inoculated into LB liquid medium and cultured at 30℃ with shaking at 180 rpm for 48 h. The culture was centrifuged at 8000 rpm for 10 min to collect the bacterial cells. The bacterial cells were washed twice with sterile physiological saline, and finally resuspended in 150 mM NaCl solution and 250 mM NaCl solution, respectively, to prepare a suspension with a concentration of 1×10⁻⁶. 7 CFU / mL of Bacillus spp. FHY1 suspension (labeled as 150mM NaCl+FHY1, 250mM NaCl+FHY1).

[0096] Preparation of control solutions: Prepare the following control solutions: sterile water (normal control), Bacillus subtilis FHY1 bacterial culture, 150mM NaCl solution (mild salt stress control), and 250mM NaCl solution (severe salt stress control).

[0097] 2. Seed treatment and culture

[0098] Select plump and uniform rice seeds, and after surface disinfection, immerse them in the following six treatment solutions prepared in step 1:

[0099] Sterile water, Bacillus spp. FHY1 bacterial suspension, 150mM NaCl solution, 250mM NaCl solution, 150mM NaCl + FHY1 bacterial suspension, 250mM NaCl + FHY1 bacterial suspension.

[0100] Each treatment was set up in 3 replicates, and all treatments were immersed in the dark at 28°C for 72 h.

[0101] 3. Results Observation and Calculation

[0102] After 72 hours of cultivation, the number of rice seeds germinated in each treatment group was counted (germination was calculated based on the germination length reaching half the seed length), and the germination rate was calculated.

[0103] The results are as follows Figure 5 As shown: the germination rate of both the sterile water treatment group (normal conditions) and the Bacillus spp. FHY1 bacterial suspension treatment group was 100%; the germination rate of the 150mM NaCl and 250mM NaCl treatment groups (salt stress control) was 0%, indicating that this salt concentration completely inhibited seed germination. However, after treatment with FHY1 bacterial suspension, the seed germination rate under 150mM NaCl and 250mM NaCl stress recovered to 27%.

[0104] This embodiment demonstrates that Bacillus subtilis FHY1 can effectively alleviate the inhibition of rice seed germination by salt stress and significantly restore its germination ability under salt stress.

[0105] Example 6: The promoting effect of Bacillus subtilis FHY1 on the growth of rice seedlings under salt stress

[0106] This embodiment uses a pot experiment to systematically evaluate the promoting effect of Bacillus subtilis FHY1 on the growth of rice seedlings under salt stress.

[0107] 1. Preparation of test materials

[0108] Preparation of Bacillus subtilis FHY1 suspension: Same as step 1 in Example 5, using 150mM and 250mM NaCl solutions to prepare suspensions with a concentration of 1×10⁻⁶. 7 CFU / mL of Bacillus hygroscopicus FHY1 suspension.

[0109] Control solutions: Prepare 150 mM and 250 mM NaCl solutions as salt stress controls.

[0110] Plant materials: After disinfecting the surface of rice seeds, germinate them in sterile water until they show white sprouts, and then sow them in flower pots containing sterilized substrate.

[0111] 2. Experimental treatment and culture

[0112] When the rice seedlings reach the three-leaf stage, select seedlings with uniform growth and treat them as follows:

[0113] Irrigation with 150mM NaCl solution (salt stress control 1);

[0114] Irrigation with a suspension of Bacillus subtilis FHY1 prepared with 150mM NaCl (150mM NaCl + FHY1).

[0115] Irrigation with 250mM NaCl solution (salt stress control 2);

[0116] Irrigation with a suspension of Bacillus subtilis FHY1 prepared with 250mM NaCl (250mM NaCl + FHY1).

[0117] All treatments should be watered with the appropriate solution every 7 days, with each application just enough to thoroughly moisten the substrate. During this period, replenish any evaporation losses with an appropriate amount of sterile water.

[0118] All potted plants were placed in an artificial climate chamber for standardized cultivation under the following conditions: photoperiod of 14h / 10h (day / night), day / night temperature of 28℃ / 25℃, and relative humidity of 70%.

[0119] The treatment lasted 21 days.

[0120] 3. Result Measurement and Analysis

[0121] On day 21 of treatment, growth indicators such as plant height, stem diameter and leaf width of rice seedlings in each treatment group were measured.

[0122] The results are as follows Figure 6 As shown, under 150 mM NaCl stress, rice plants inoculated with Bacillus subtilis FHY1 suspension (150 mM NaCl + FHY1) exhibited significantly better plant height, stem diameter, and leaf width than the non-inoculated control group (150 mM NaCl) under the same salinity. Similarly, under high salt stress of 250 mM NaCl, rice plants inoculated with Bacillus subtilis FHY1 (250 mM NaCl + FHY1) also showed significantly better growth performance than the corresponding salt stress control group (250 mM NaCl).

[0123] This embodiment demonstrates that Bacillus subtilis FHY1 can effectively promote the vegetative growth of rice seedlings under salt stress and enhance the crop's tolerance to saline-alkali adversity.

[0124] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A strain of Bacillus subtilis Paenibacillus cathormii FHY1, characterized in that, The Bacillus spp. FHY1 was deposited on October 16, 2025, at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 36200.

2. A microbial inoculant, characterized in that, The active ingredient includes the Bacillus hygroscopicus FHY1 as described in claim 1.

3. The application of the Bacillus subtilis FHY1 as described in claim 1 or the microbial agent as described in claim 2 in the control of rice blast, characterized in that, The rice blast disease is caused by a pathogen. Magnaporthe oryzae cause.

4. A method for preventing and controlling rice blast, characterized in that, The process includes treating rice with the Bacillus spp. FHY1 as described in claim 1 or the microbial agent as described in claim 2; the rice blast disease is caused by a pathogen. Magnaporthe oryzae cause.

5. The application of the Bacillus spp. FHY1 as described in claim 1 or the microbial agent as described in claim 2 in inhibiting pathogenic bacteria, characterized in that, The pathogens include rice blast fungus, Fusarium oxysporum, Fusarium graminearum, Sclerotinia sclerotiorum, and anthracnose fungus.

6. The application of the Bacillus spp. FHY1 as described in claim 1 or the microbial agent as described in claim 2 in improving the salt resistance of rice.

7. The application according to claim 6, characterized in that, Improving rice's salt tolerance includes enhancing seed germination and seedling growth under salt stress.

8. A method for improving the salt tolerance of rice, characterized in that, The method includes the step of treating rice seeds and / or seedling roots with Bacillus spp. FHY1 as described in claim 1 or the microbial agent as described in claim 2.

9. The method according to claim 8, characterized in that, Improving rice's salt tolerance includes enhancing seed germination and / or seedling growth under salt stress.

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