Bacillus velezensis HP26 with salt-tolerant growth-promoting effect, microbial agent and application

Abstract

The invention belongs to the technical field of agricultural microorganisms, and particularly relates to bacillus velezensis HP26 with salt-tolerant and growth-promoting effects, a microbial agent and application. The bacillus velezensis HP26 is preserved in the China General Microbiological Culture Collection Center on September 16, 2025, and the preservation number of the bacillus velezensis HP26 is CGMCC (China General Microbiological Culture Collection Center) No.35936; the bacillus velezensis HP26 has excellent salt tolerance, strong crop growth promoting property and remarkable soil improvement capability at the same time; the strain plays a role in salt tolerance and growth promotion mainly by activating a molecular pathway related to a Ca < 2 + > signal in a'plant-pathogenic bacterium interaction 'pathway, and specifically, the expression of related genes such as CNGC2, CML23, CAM7, CDPK20 and WRKY33 is up-regulated. The separated bacillus velezensis overcomes the defect of single function of the existing bacillus velezensis, and can stably exert multiple effects in a saline-alkali soil environment.

Description

Technical Field

[0002] This invention belongs to the field of agricultural microbial technology, specifically relating to a strain of Bacillus belye HP26 with salt-tolerant growth-promoting effects, microbial agents, and their applications. Background Technology

[0003] With the intensification of global climate change and unreasonable agricultural production activities, soil salinization has become an increasingly prominent problem. Saline-alkali land, due to its high salt concentration and high pH value, inhibits the ability of crop roots to absorb water and nutrients, disrupts crop cell structure and physiological metabolic balance, leading to slow crop growth and reduced yields, severely restricting sustainable agricultural development. Statistics show that the global area of ​​saline-alkali land exceeds 950 million hectares, with approximately 100 million hectares in my country. The potential for usable saline-alkali land resources is enormous, but scientific methods are needed for its improvement and utilization.

[0004] Traditional methods for improving saline-alkali land include physical methods (such as deep plowing and salt leaching) and chemical methods (such as applying gypsum and humic acid), but these methods have drawbacks such as high cost, long cycle time, and potential for secondary pollution. Microbial improvement technology, due to its advantages of being environmentally friendly, low-cost, and highly sustainable, has become a research hotspot in saline-alkali land management in recent years. Among these, Bacillus subtilis, with its strong resilience, rapid reproduction rate, and ability to secrete various growth-promoting substances (such as auxins and antibacterial substances), is widely used in agricultural production.

[0005] While some Bacillus strains have been reported to possess certain salt tolerance or growth-promoting functions in existing technologies, most strains suffer from a single prominent function and insufficient overall effectiveness. For example, some strains can only promote crop growth but cannot survive stably in high-salt environments; others, while salt-tolerant, have insignificant growth-promoting effects and limited improvement on soil physicochemical properties. For instance, the invention patent CN119662468A discloses a Bacillus berghei strain with salt tolerance and growth-promoting functions, a bio-organic fertilizer, and its application. This Bacillus berghei strain exhibits salt tolerance and growth-promoting functions, but it cannot improve soil physicochemical properties. Furthermore, currently, there is a scarcity of microbial resources that can be practically applied to social production, especially strains that can not only adapt to high-salt environments but also effectively promote the salt-tolerant growth of plants in saline-alkali land and improve soil for soil remediation purposes, and their applications are still rare. Therefore, screening a Bacillus strain that combines excellent salt tolerance, strong growth-promoting properties, and soil improvement capabilities is of great significance for promoting the efficient utilization of saline-alkali land in agriculture. Summary of the Invention

[0006] The first objective of this invention is to provide a strain of Bacillus berleis HP26 with salt-tolerant growth-promoting effects. This Bacillus berleis HP26 not only promotes crop growth and enhances crop salt tolerance, but also improves the physical and chemical properties of the soil.

[0007] A second objective of this invention is to provide a microbial agent whose active ingredient includes the aforementioned salt-tolerant and growth-promoting Bacillus berreatus HP26.

[0008] The third objective of this invention is to provide an application of Bacillus belye HP26 with salt-tolerant growth-promoting effects.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A strain of *Bacillus belye* HP26 exhibiting salt-tolerant growth-promoting effects was deposited at the China General Microbiological Culture Collection Center on September 16, 2025, with accession number CGMCC No. 35936. This *Bacillus belye* HP26 activates the plant-pathogen interaction pathway, specifically the pathway involving calcium... 2+ Signal-related molecular pathways exert salt tolerance-promoting effects.

[0010] Furthermore, the Bacillus belyss HP26 exerts its salt tolerance-promoting effect by upregulating the expression of the CNGC2, CML23, CAM7, CDPK20, and WRKY33 genes.

[0011] Furthermore, the Bacillus belye HP26 is tolerant to sodium chloride solutions with a mass fraction ≤6%.

[0012] A microbial agent, wherein the active ingredient of the microbial agent includes Bacillus belye HP26, which has a salt-tolerant growth-promoting effect.

[0013] Furthermore, the dosage form of the microbial agent includes, but is not limited to, liquid agents, solid powders, or granules; the effective viable count of *Bacillus belyssima* HP26 in the liquid agent is ≥1×10⁻⁶. 7 CFU / mL; the effective viable count of Bacillus vesiculus HP26 in the solid powder is ≥1×10⁻⁶. 7 CFU / g; The effective viable count of Bacillus vesiculus HP26 in the granules is ≥1×10⁻⁶. 7 CFU / g.

[0014] The application of Bacillus vesiculosus HP26 or microbial agents with salt-tolerant growth-promoting effects in promoting crop growth and enhancing crop salt tolerance, as mentioned above; the Bacillus vesiculosus HP26 or microbial agents with salt-tolerant growth-promoting effects activate the "plant-pathogen interaction" pathway and the interaction with Ca... 2+ Signal-related molecular pathways, thereby promoting crop growth and enhancing crop salt tolerance.

[0015] Furthermore, as mentioned above, Bacillus berreatus HP26 or microbial agents with salt-tolerant growth-promoting effects can promote crop growth and enhance crop salt tolerance by upregulating the expression of CNGC2, CML23, CAM7, CDPK20, and WRKY33 genes.

[0016] Furthermore, the promotion of crop growth refers to promoting crop growth in normal soil or saline-alkali soil.

[0017] The application of Bacillus berberis HP26 or microbial agents with salt-tolerant growth-promoting effects in improving soil physical and chemical properties, as mentioned above.

[0018] The beneficial effects of this invention are: 1) The Bacillus belye isolated by this invention has excellent salt tolerance, strong crop growth promotion and significant soil improvement ability, overcoming the shortcomings of existing Bacillus strains with single function, and can stably exert multiple effects in saline-alkali environments.

[0019] 2) The Bacillus belye of the present invention can significantly increase the plant height, root length and biomass of crops such as tomatoes and wheat. Especially under salt stress conditions, it can effectively alleviate the inhibition of crop growth by salt damage and improve crop resistance.

[0020] 3) Microbial agents containing Bacillus vesiculosus of the present invention can significantly improve soil fertility and enzyme activity, improve the soil micro-ecological environment, and provide good soil conditions for crop growth.

[0021] 4) The preparation process of Bacillus belye and microbial agents of the present invention is simple, low-cost and environmentally friendly, and applicable to the planting of various crops in saline-alkali land. It has important practical significance for promoting the development and utilization of saline-alkali land resources and ensuring the sustainable development of agriculture. Attached Figure Description

[0022] Figure 1 This is a colony morphology diagram of Bacillus belyss HP26. Figure 2 Phylogenetic tree diagram of Bacillus belyss HP26; Figure 3 Figure showing the growth of Bacillus belye HP26 in media with different salt concentrations; Figure 4 The diagram shows the effect of Bacillus belyss HP26 on tomato growth and salt tolerance in Example 3. In the diagram, A is the growth status of tomatoes in the four treatment groups, B is the plant height of tomatoes in the four treatment groups, C is the root length of tomatoes in the four treatment groups, D is the aboveground fresh weight of tomatoes in the four treatment groups, E is the underground fresh weight of tomatoes in the four treatment groups, F is the aboveground dry weight of tomatoes in the four treatment groups, and G is the underground dry weight of tomatoes in the four treatment groups. Figure 5 The diagram shows the effect of Bacillus belyss HP26 on wheat growth and salt tolerance in Example 3. In the diagram, A is the growth status of wheat in the four treatment groups, B is the plant height of wheat in the four treatment groups, C is the root length of wheat in the four treatment groups, D is the aboveground fresh weight of wheat in the four treatment groups, E is the underground fresh weight of wheat in the four treatment groups, F is the aboveground dry weight of wheat in the four treatment groups, and G is the underground dry weight of wheat in the four treatment groups. Figure 6 The graph shows the effect of Bacillus belyss HP26 on the biochemical indicators of tomatoes in Example 3. In the graph, A is the H2O2 content of tomatoes in the four treatment groups, B is the MDA content of tomatoes in the four treatment groups, C is the POD content of tomatoes in the four treatment groups, D is the CAT content of tomatoes in the four treatment groups, E is the PRO content of tomatoes in the four treatment groups, and F is the SS content of tomatoes in the four treatment groups. Figure 7 The graph shows the effect of Bacillus belyss HP26 on wheat biochemical indicators in Example 3. In the graph, A is the H2O2 content of wheat in the four treatment groups, B is the MDA content of wheat in the four treatment groups, C is the CAT content of wheat in the four treatment groups, D is the POD content of wheat in the four treatment groups, E is the PRO content of wheat in the four treatment groups, and F is the SS content of wheat in the four treatment groups. Figure 8 To induce the "plant-pathogen interaction" pathway and Ca2+ in Bacillus belyss HP26 2+ The graph shows the expression of genes related to the signaling pathway. A represents the transcriptome sequencing results of tomato seedlings inoculated with and uninoculated with HP26 under normal conditions; B represents the transcriptome sequencing results of tomato seedlings inoculated with and uninoculated with HP26 under salt stress; C represents the transcriptome sequencing results of tomato seedlings under normal and salt stress conditions; D represents the transcriptome sequencing results of tomato seedlings inoculated with HP26 under salt stress and under normal conditions; E represents the expression of genes related to the signaling pathway. 2+ Signal pathway diagram, F represents the calcium level of tomato seedlings under different treatment conditions. 2+ A graph showing the expression of genes related to the signaling pathway, where G represents the calcium content in tomato seedlings under different treatments. 2+ Concentration graph; Figure 9 For Ca 2+ The effect of channel / signal inhibitors on the salt tolerance and growth-promoting effect of Bacillus belyssus HP26 is shown in the figure. A is the growth status of tomato seedlings in different treatment groups, B is the plant height of tomatoes in different treatment groups, C is the root length of tomatoes in different treatment groups, D is the aboveground fresh weight of wheat in the four treatment groups, E is the underground fresh weight of wheat in the four treatment groups, F is the aboveground dry weight of wheat in the four treatment groups, and G is the underground dry weight of wheat in the four treatment groups. Figure 10 The diagram shows the effects of Bacillus belyss HP26 on the physical and chemical properties of field soil. Detailed Implementation

[0023] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0024] The mock in the figure represents the control group without HP26.

[0025] Example 1 Bacillus belesiensis ( Bacillus velezensis Isolation, identification and preservation of HP26 1. Culture medium components Nutrient Agar (NA) medium: 10 g peptone, 3 g beef extract, 5 g sodium chloride, 15 g agar, 1 L distilled water, pH 7.2-7.4.

[0026] 2. Sample dilution and coating Take 0.5 g of naturally fermented pig manure organic fertilizer, suspend and shake it in 4.5 mL of sterile physiological saline, and that is 10. -1 For gradient (10-fold dilution), take 0.5 mL of this dilution and suspend it in 4.5 mL of sterile physiological saline with shaking. This yields a 10-fold dilution. -2 Gradient dilution (100x dilution), and so on, until diluted to 100x. -6 Gradients. Take 100 μL of each of the six dilution gradients and spread it on NA solid medium plates. Prepare two parallel aliquots, invert them, and incubate them in a 30 ℃ constant temperature incubator for 24-36 h, observing them at irregular intervals.

[0027] 3. Strains Isolation and Purification Remove all plates from the same sample that have grown colonies, select dilution plates with clear single colonies and appropriate numbers, transfer colonies with different morphologies from the plates to new NA plates, and perform partitioned purification. Repeat the purification until single colonies appear, and then repeat the streak culture at least 5 times.

[0028] 4. Dyeing and Preservation Colonies of the bacterial strain to be tested were picked and placed in the central area of ​​a glass slide. After four steps of primary staining with ammonium oxalate-crystal violet solution, mordant staining with iodine solution, destaining with 75% ethanol, and counterstaining with safranin, the colonies were observed under a microscope and the staining results were recorded. The purified and stained single colonies were picked from NA solid medium plates and transferred to sterile NA liquid medium. They were incubated at 180 r / min and 30 ℃ for 24±2 h. After shaking and mixing, 60% sterile glycerol and bacterial solution were mixed at a ratio of V:V=1:1, dispensed into sterile preservation tubes, labeled, and stored in a -80 ℃ refrigerator.

[0029] 5. Strain identification Morphological identification: The strain was incubated on NA medium plates at 30 °C for 12 h, such as... Figure 1 As shown, the colony surface is rough, white and opaque, with intact edges and uniform texture.

[0030] Molecular biological identification: Plates containing the corresponding numbered strains were removed from the 4 ℃ freezer, and single colonies were picked as DNA templates for PCR amplification and 16S rDNA sequencing and sequence alignment. The specific procedures are as follows: (1) Amplification system: 50 μL system, consisting of five parts: Taq enzyme Mix (25 μL, purchased from Sangon Biotech Co., Ltd.), upstream primer 27F (1 μL), downstream primer 1492R (1 μL), DNA template (1 μL), ddH2O (22 μL). The sequence of 27F is: 5'-AGAGTTTGATCMTGGCTCAG-3', and the sequence of 1492R is: 5'-GGYTACCTTGTTACGACTT-3'; (2) Amplification conditions: First step pre-denaturation 95 ℃, 7 min; second step denaturation 95 ℃, 30 s; third step annealing 55 ℃, 30 s; fourth step extension 72 ℃, 90 s, for a total of 30 cycles; fifth step final extension 72 ℃, 5 min. (3) Agarose gel electrophoresis: Weigh 1 g of agarose and dissolve it in 100 mL of TBE electrophoresis buffer. Microwave heat until the solution is clear and transparent. Add 1‰ of GelRed nucleic acid dye, shake well, and let stand until there are no bubbles. Slowly pour it into the gel plate and let it stand for about 1 h. Take out the solidified gel block and place it in the electrophoresis tank. Add 4 μL of PCR amplification product to each gel well. Run the gel at 120 V for 20 min. Take out the gel block and place it in the gel imaging instrument. Select UV light and take a picture. Record the sample number corresponding to the clear band at 1500 bp on the gel block. Place the remaining PCR amplification product of the sample in a 4 ℃ refrigerator. (4) DNA purification: Take out the PCR amplification products stored in the 4 ℃ refrigerator and purify the PRC products using the AxyPrep™ PCRCleanup Kit.

[0031] (5) Sequence identification: The resuspended DNA obtained in the above steps was sent to Sangon Biotech Co., Ltd. for sequencing. The 16S rRNA gene sequence obtained by sequencing was 1400bp (SEQ ID NO.1). Figure 2 The phylogenetic tree of the strain provided in this invention shows that it is *Bacillus belye* (…). Bacillus velezensisThe sample, named HP26, was deposited at the China General Microbiological Culture Collection Center on September 16, 2025, with accession number CGMCC No. 35936.

[0032] SEQ ID NO. 1: Salt tolerance identification of the strain: NB liquid medium with NaCl concentrations of 0%, 1%, 2%, 3%, 4%, 5%, and 6% was prepared. Activated Bacillus belyss HP26 strain was inoculated into each concentration of NB liquid medium at a 1% inoculation rate. After incubation at 30℃ and 180 r / min for 24 h, the OD of each group was measured using a UV spectrophotometer. 600 Values, with 3 repetitions per group. From Figure 3 It can be seen that Bacillus belye HP26 can grow in the range of NaCl concentration from 0 to 6%, with the best growth at a NaCl concentration of 0 to 2%. It still maintains good growth activity at a NaCl concentration of 3 to 4%. Even at a high salt concentration of 5 to 6%, it can still maintain a certain growth capacity, indicating that the Bacillus belye HP26 strain of the present invention has excellent salt tolerance and can meet the application requirements of saline-alkali land environment.

[0033] Example 2 Bacillus belesi ( Bacillus velezensis Preparation of HP26 microbial inoculants 1. Preparation of liquid bacterial agent Xanthan gum was added to sterile distilled water and stirred until a uniform, particle-free gel was formed. Potassium sorbate and polysorbate were added to the gel, and stirring was continued to obtain an adjuvant mixture. The HP26 bacterial suspension from Example 1 was added to the adjuvant mixture at a ratio of 20% (v / v), and stirring was continued to ensure that the HP26 bacterial suspension and the adjuvant mixture were mixed evenly, resulting in microbial aqueous suspensions containing different amounts of the target strain. The viable count of the bacterial agent was detected by plate counting and stored in a cool, dry place. 0.15 g of xanthan gum was added to every 100 mL of sterile water, and 0.1 g of potassium sorbate and 0.3 g of polysorbate were added to every 100 mL of gel.

[0034] 2. Preparation of solid powders First, dry the peat moss, vermiculite, and humic acid separately in a 60°C oven, then sterilize them with ultraviolet light for 30 minutes, and cool them to room temperature for later use. Next, according to the formula ratio of peat moss:vermiculite:humic acid = 5:3:1 by mass, add the peat moss, vermiculite, and humic acid to a double-helix mixer and mix for 15 minutes. Then add HP26 microbial powder, at 5% of the total mass of the peat moss, vermiculite, and humic acid, and continue mixing for 30 minutes to ensure uniform mixing. Package the qualified solid powder and store it in a dry, ventilated place.

[0035] 3. Preparation of granules Prepare a 1.5% (w / w) CMC-Na solution by dissolving sodium carboxymethyl cellulose (CMC-Na) in sterile distilled water. Then, add HP26 powder to a disc granulator, turn on the granulator, and slowly spray the CMC-Na solution at a rate of 15%-20% of the HP26 powder mass, controlling the spraying speed to gradually form granules with a diameter of 1-2 mm. Next, place the prepared wet granules in a forced-air drying oven to dry them uniformly. Finally, sieve the dried granules using a 10-mesh standard sieve, and sample the granules for testing the viable bacteria count, moisture content, and granule strength, then store them in a cool, dry place.

[0036] Example 3 Bacillus belesiensis ( Bacillus velezensis Application of HP26 in promoting crop growth and improving crop salt tolerance Using the Bacillus berberis HP26 suspension from Example 1 (viable count ≥1×10⁻⁶) 7 The test product was (CFU / mL), and experiments were conducted in an artificial climate chamber using tomatoes and wheat as subjects. Four experimental treatment groups were set up for each: Treatment 1 was under normal conditions; Treatment 2 was under 200 mM NaCl salt stress; Treatment 3 was under normal conditions plus HP26 suspension; and Treatment 4 was under 200 mM NaCl salt stress plus HP26 suspension.

[0037] Select plump, pest-free tomato and wheat seeds and disinfect them in a 75% alcohol solution for 1 minute, then rinse thoroughly with distilled water to ensure no residue. Soak the seeds in sterile water for 24 hours, then evenly arrange them on petri dishes lined with filter paper. Continue culturing in a constant temperature incubator for 48-72 hours to allow germination. Finally, select tomatoes and wheat seeds with uniform germination and growth to transplant into planting pots (5×5×8 cm). Each treatment has 3 replicates, with 5 seedlings per replicate. When the tomato seedlings have 2 true leaves and the wheat seedlings have 3 true leaves, treatments 1 and 3 are treated with equal volumes of sterile water and 1×10⁻⁶ oz. 7 Treatments 2 and 4 were irrigated with a solution of Bacillus belye HP26 containing CFU / mL. Equal volumes of solutions containing 200 mM NaCl and 1×10⁻⁶ CFU / mL were used for irrigation. 7 The plant was irrigated with 200 mM NaCl solution containing CFU / mL Bacillus belye HP26. The treatment was repeated one week later, and plant growth and biochemical indicators were assessed two weeks later.

[0038] like Figure 4 and 5As shown, under normal conditions, compared with the uninoculated group, the tomato plant height (PH), root length (RL), aboveground fresh weight (SFW), belowground fresh weight (RFW), aboveground dry weight (SDW), and belowground dry weight (RDW) inoculated with HP26 increased by 15.95%, 14.71%, 32.58%, 37.52%, 38.13%, and 24.37%, respectively; while the wheat plant height, root length, aboveground fresh weight, belowground fresh weight, aboveground dry weight, and belowground dry weight inoculated with HP26 increased by 18.53%, 11.39%, 25.48%, 15.91%, 13.95%, and 21.52%, respectively. Under salt stress conditions, compared with the uninoculated HP26 experimental group, the plant height, root length, above-ground fresh weight, below-ground fresh weight, above-ground dry weight, and below-ground dry weight of HP26-inoculated tomatoes increased by 25.98%, 15.69%, 29.66%, 45.71%, 24.04%, and 25.00%, respectively; while the plant height, root length, above-ground fresh weight, below-ground fresh weight, above-ground dry weight, and below-ground dry weight of HP26-inoculated wheat increased by 10.53%, 14.29%, 23.91%, 24.49%, 13.43%, and 22.38%, respectively.

[0039] like Figure 6 and 7 As shown, under normal conditions, there were no significant differences in biochemical indicators between HP26-inoculated and uninoculated tomatoes and wheat. Under salt stress, compared with the uninoculated experimental group, HP26-inoculated tomatoes showed increases of soluble sugar (SS), proline (PRO), catalase (CAT), and peroxidase (POD) activities of 15.84%, 23.76%, 37.05%, and 33.53%, respectively, while hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents decreased by 18.95% and 19.13%, respectively. HP26-inoculated wheat showed increases of soluble sugar, proline, catalase, and peroxidase activities of 32.59%, 31.93%, 35.99%, and 27.71%, respectively, while hydrogen peroxide and MDA contents decreased by 28.63% and 35.05%, respectively.

[0040] Example 4 Bacillus belesiensis ( Bacillus velezensis Analysis of the mechanism by which HP26 enhances crop salt tolerance Using tomatoes as the research subject, transcriptome sequencing was performed on tomato seedlings inoculated and uninoculated with HP26 under normal and salt stress conditions. Figure 8AD analysis showed that HP26 enhanced tomato salt tolerance by activating multiple molecular pathways, among which the plant-pathogen interaction pathway was significantly induced by salt stress, and its inducibility was further enhanced after HP26 inoculation. Most of the HP26-induced plant-pathogen interaction pathways are related to Ca2+. 2+ This is related to signaling pathways, specifically manifested as upregulation of the expression of genes related to CNGC2, CML23, CAM7, CDPK20, and WRKY33. Figure 8 As can be seen from EG, regardless of whether under normal conditions or salt stress conditions, the Ca2+ levels in tomato seedlings inoculated with HP26 were significantly lower. 2+ The contents of all samples increased significantly, indicating that Ca... 2+ Signaling pathways play a crucial role in HP26's enhancement of salt tolerance in tomatoes. From Figure 9 It can be seen that using Ca 2+ Treatment of tomato seedlings with the channel / signal inhibitors LaCl3 and W-7 revealed that the growth-promoting and salt-tolerance effects of HP26 were suppressed. These results indicate that HP26 is dependent on plant calcium. 2+ Signaling pathways enhance the salt tolerance of tomatoes.

[0041] Example 5 Bacillus belesiensis ( Bacillus velezensis Application of HP26 in improving soil physical and chemical properties Using the Bacillus berberis HP26 suspension from Example 1 (viable count ≥1×10⁻⁶) 7 The test product was Bacillus vesiculosus (CFU / mL), and experiments were conducted in normal field wheat planting areas. Two experimental treatments were set up: Treatment 1 received no fertilizer, and Treatment 2 received Bacillus vesiculosus HP26 suspension. Each experimental plot was 1.5 × 1.5 m, with three replicates per treatment. Bacillus vesiculosus HP26 suspension was applied to each plot at the tillering, jointing, and heading stages, with 10 L applied at each stage. Rhizosphere soil samples were collected at the grain-filling stage to determine soil organic matter, available nitrogen, available phosphorus, and available potassium content, as well as the activities of β-glucosidase, urease, neutral phosphatase, and catalase. Figure 10 It can be seen that the application of Bacillus vesiculosus HP26 suspension significantly increased the contents of soil organic matter, available nitrogen, available phosphorus, and available potassium by 11.72%, 25.37%, 22.70%, and 23.62%, respectively. It also improved the activities of β-glucosidase, urease, neutral phosphatase, and catalase in the soil by 46.67%, 23.68%, 18.54%, and 17.38%, respectively.

[0042] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This disclosure is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the claims.

[0043] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. The scope of patent protection of the present invention shall be determined by the claims. Similarly, any equivalent structural changes made based on the content of the present invention's specification shall also be included within the scope of protection of the present invention.

Claims

1. A strain of Bacillus belye HP26 exhibiting salt-tolerant growth-promoting effects, characterized in that, Bacillus belye HP26 was deposited at the China General Microbiological Culture Collection Center on September 16, 2025, with accession number CGMCC No. 35936. This Bacillus belye HP26 activates the plant-pathogen interaction pathway, specifically the pathway involving Ca2+. 2+ Signal-related molecular pathways exert salt tolerance-promoting effects.

2. The Bacillus belye HP26 with salt-tolerant growth-promoting effect according to claim 1, characterized in that, The Bacillus belyss HP26 exerts its salt tolerance-promoting effect by upregulating the expression of the CNGC2, CML23, CAM7, CDPK20, and WRKY33 genes.

3. The *Bacillus belye* HP26 with salt-tolerant growth-promoting effect according to claim 1, characterized in that, The Bacillus berreatus HP26 is resistant to sodium chloride solution with a mass fraction ≤6%.

4. A microbial inoculant, characterized in that, The active ingredient of the microbial agent includes Bacillus belye HP26, which has a salt-tolerant growth-promoting effect as described in claim 1.

5. The microbial agent according to claim 4, characterized in that, The dosage form of the microbial agent includes, but is not limited to, liquid agents, solid powders, or granules; the effective viable count of *Bacillus berberis* HP26 in the liquid agent is ≥1×10⁻⁶. 7 CFU / mL; the effective viable count of Bacillus vesiculus HP26 in the solid powder is ≥1×10⁻⁶. 7 CFU / g; The effective viable count of Bacillus vesiculus HP26 in the granules is ≥1×10⁻⁶. 7 CFU / g.

6. The application of *Bacillus vesiculosus* HP26 with salt-tolerant growth-promoting effect as described in any one of claims 1-3, or the microbial agent as described in any one of claims 4-5, in promoting crop growth and enhancing crop salt tolerance; wherein the *Bacillus vesiculosus* HP26 with salt-tolerant growth-promoting effect or the microbial agent activates the "plant-pathogen interaction" pathway with Ca... 2+ Signal-related molecular pathways, thereby promoting crop growth and enhancing crop salt tolerance.

7. The application of Bacillus belye HP26 or microbial inoculant with salt-tolerant growth-promoting effect according to claim 6, characterized in that, The salt-tolerant Bacillus berreatus HP26 or microbial agents that promote growth by upregulating the expression of CNGC2, CML23, CAM7, CDPK20, and WRKY33 genes can promote crop growth and enhance crop salt tolerance.

8. The application of Bacillus belye HP26 or microbial inoculant with salt-tolerant growth-promoting effect according to claim 6, characterized in that, The promotion of crop growth refers to promoting the growth of crops in normal soil or saline-alkali soil.

9. The application of Bacillus berreatus HP26 with salt-tolerant growth-promoting effect as described in any one of claims 1-3, or the microbial agent as described in any one of claims 4-5, in improving soil physical and chemical properties.

Images