Bacillus altitudinis with functions of dephosphorization, plant growth promotion and drought resistance improvement and application thereof

Abstract

This invention discloses a strain of *Bacillus hygroscopicus* with functions of phosphorus solubilization, promoting plant growth, and enhancing plant drought resistance, and its applications. The *Bacillus hygroscopicus* is *Bacillus hygroscopicus*. Bacillus height Strain B27, with its registration number CGMCC No. 36877 at the China General Microbiological Culture Collection Center, has been shown to exhibit significant improvements in several experiments. In tobacco inoculation experiments, compared to the control group, the B27-inoculated tobacco seedlings showed a significant increase in lateral root number, root hair length, and aboveground and belowground fresh weight. Similarly, in apple rootstock inoculation experiments, compared to the control group, the B27-inoculated apple plants showed significant increases in plant height, aboveground fresh weight, root surface area, root tip number, root hair length, root hair quantity, and phosphorus content. Finally, in Arabidopsis thaliana inoculation experiments, compared to the control group, the B27-inoculated Arabidopsis seedlings showed a significant improvement in drought resistance.

Description

Technical Field

[0001] This invention belongs to the field of biotechnology, specifically relating to a strain of Bacillus subtilis that has functions of phosphorus solubilization, promoting plant growth and improving plant drought resistance, and its applications. Background Technology

[0002] Phosphorus is one of the essential macronutrients for plant growth and development, participating in important physiological processes such as energy transfer, photosynthesis, cell division, and genetic information transmission. However, although the total phosphorus content in soil is high, the vast majority exists in the form of inorganic phosphorus (such as calcium phosphate, iron phosphate, and aluminum phosphate) or organic phosphorus (such as phytates, phospholipids, and nucleic acids), which are difficult for plants to directly absorb and utilize. As a result, the scarcity of available phosphorus in the soil has become one of the key factors limiting crop yield.

[0003] In traditional agricultural production, crops primarily rely on the large-scale application of chemical phosphate fertilizers to meet their phosphorus requirements. However, the utilization rate of chemical phosphate fertilizers during the current season is extremely low. Unused phosphate fertilizers are fixed and accumulated in the soil, leading not only to resource waste and increased production costs but also to environmental problems such as eutrophication of water bodies. Therefore, developing and utilizing inherent phosphorus resources in the soil and employing environmentally friendly bio-phosphorus solubilization technologies has become an urgent need for the sustainable development of modern agriculture.

[0004] Phosphate-solubilizing microorganisms (PSMs) can convert insoluble phosphorus in the soil into soluble phosphorus for plant absorption by secreting organic acids, protons, chelating agents, and phosphatases. Among them, Bacillus is a common type of phosphorus-solubilizing microorganism. Due to its simple cultivation conditions, strong resistance, ease of large-scale production and preservation, and generally considered safe for humans and the environment, it has shown good application potential in the field of microbial fertilizers and is gradually realizing industrial application. Examples include Bacillus polymyxa, Bacillus amyloliquefaciens, and Bacillus subtilis. While Bacillus altissima also belongs to the Bacillus genus, current reports on it mainly focus on its antagonistic function against plant pathogens, such as antagonism and control of rice blast, tea anthracnose, and tobacco black shank; there are few studies and reports on its effects on plant growth promotion, root architecture, and stress resistance.

[0005] Given that the currently isolated phosphorus-solubilizing strains have relatively limited functions and inconsistent application effects, and considering the scarcity of strains possessing multiple functions such as efficient phosphorus solubilization, systematic regulation of root architecture (root hairs, lateral roots, taproots), promotion of aboveground growth, and significant enhancement of plant drought resistance, isolating and screening novel Bacillus strains with multiple synergistic growth-promoting functions is of great significance for developing efficient and multifunctional microbial fertilizers and promoting green agriculture. Summary of the Invention

[0006] The purpose of this invention is to provide a highland Bacillus strain with functions of phosphorus solubilization, promoting plant growth and improving plant drought resistance, and its applications.

[0007] Firstly, this invention claims protection for a strain of Bacillus hygroscopicus. Altitude Bacillus .

[0008] The Bacillus hygroscopicus claimed in this invention Altitude Bacillus Highland Bacillus Altitude Bacillus B27, the registration number of this strain at the China General Microbiological Culture Collection Center is CGMCC No. 36877.

[0009] Secondly, this invention claims protection for bacteria containing the aforementioned Bacillus hygroscopicus. Altitude Bacillus Combinations of or their descendants.

[0010] In some embodiments, the composition is a culture; the culture is the *Bacillus hygroscopicus*. Altitude Bacillus The substance obtained by culturing its offspring in a microbial culture medium, including all substances within the culture vessel, i.e., fermentation products, such as those containing the aforementioned Bacillus hygroscopicus. Altitude Bacillus or its offspring and the substance secreted into the liquid culture medium, i.e., the fermentation broth, or such as containing the aforementioned Bacillus hygroscopicus. Bacillus height or its offspring and the substances secreted into solid culture media, namely solid fermentation products.

[0011] In some embodiments, the composition may be a microbial agent, a microecological preparation, or a bio-fertilizer. The active ingredient of the microbial agent, microecological preparation, or bio-fertilizer may be *Bacillus hygroscopicus* as described in the first aspect above. Bacillus height or its descendants, the aforementioned Bacillus hygroscopicus Altitude Bacillus Metabolites of or derived thereof and / or the aforementioned Bacillus hygroscopicus Altitude Bacillus The active ingredients of the microbial agent, microecological preparation, or biofertilizer, or its progeny, may also contain other biological and / or non-biological components. The other active ingredients of the microbial agent, microecological preparation, or biofertilizer can be determined by those skilled in the art based on the desired effect.

[0012] In addition to the active ingredients, the microbial agent, microecological preparation, or biofertilizer may also contain a carrier. The carrier may be a biologically inert carrier commonly used in the pesticide field. The carrier may be a solid carrier or a liquid carrier; the solid carrier may be a mineral material, plant material, or polymer compound; the mineral material may be at least one of clay, talc, kaolin, montmorillonite, white carbon, zeolite, silica, and diatomaceous earth; the plant material may be at least one of wheat flour, soybean flour, and starch; the polymer compound may be polyvinyl alcohol and / or polyethylene glycol; the liquid carrier may be an organic solvent, vegetable oil, mineral oil, or water; the organic solvent may be decane and / or dodecane.

[0013] The formulation of the microbial agent, microecological preparation, or bio-fertilizer can be of various forms, such as liquid, emulsion, suspension, powder, granules, wettable powder, or water-dispersible granules.

[0014] Depending on the requirements, surfactants (such as Tween 20, Tween 80, etc.), binders, stabilizers, pH adjusters, etc. may also be added to the microbial agents, microecological preparations, or biofertilizers.

[0015] In this invention, the composition has at least one of the following properties: A1) Phosphorus solubilization; A2) Promotes plant growth and development; A3) Improve plant drought resistance; A4) Promotes phosphorus absorption by plants.

[0016] In some specific embodiments, the composition is a B27 bacterial suspension, and the specific preparation method is as follows: 1) The above-mentioned Bacillus cereus Altitude Bacillus The B27 strain was cultured on LB solid medium for 12 hours to obtain the activated strain. 2) The activated strain was cultured in LB liquid medium for 12-24 hours to obtain B27 bacterial culture; 3) Centrifuge the B27 bacterial culture (e.g., at 6000 rpm for 6 min), collect the bacterial precipitate, and resuspend the precipitate in deionized water to obtain a B27 bacterial suspension; the OD of the B27 bacterial suspension... 600nm =0.6.

[0017] Furthermore, step 2) includes the following steps: 2-1) The activated strain was placed in a 1.5 mL centrifuge tube containing 1 mL of LB liquid medium and cultured in a shaker at 37 °C for 12 h to obtain a small shaken bacterial solution; 2-2) Pour the shaken bacterial solution into a 100mL Erlenmeyer flask containing 50mL LB liquid culture medium and incubate in a shaker at 37℃ for 12h to obtain the B27 bacterial solution.

[0018] Thirdly, this invention claims protection for the aforementioned Bacillus hygroscopicus. Altitude Bacillus or its descendants or the above compositions in any of the following applications: C1) Phosphorus solubilization; C2) Preparation of phosphorus-solubilized products; C3) Promotes plant growth and development; C4) Prepare products that promote plant growth and development; C5) Improves plant drought resistance; C6) Prepare products that improve plant drought resistance; C7) Promotes phosphorus absorption in plants; C8) to prepare products that promote phosphorus absorption in plants.

[0019] Fourthly, the present invention claims a method for promoting plant growth and development, improving plant drought resistance, or promoting plant phosphorus absorption.

[0020] The method for promoting plant growth and development, improving plant drought resistance, or promoting plant phosphorus absorption provided by this invention includes the following steps: using the above-mentioned Bacillus subtilis. Altitude Bacillus The plant root or its growth substrate, or its offspring or the above-mentioned composition, are used to treat the plant root or its growth substrate to promote plant growth and development, improve plant drought resistance, or promote plant phosphorus absorption.

[0021] In some embodiments, the treatment is carried out by spreading a suspension of B27 bacteria onto a tobacco seedling culture medium.

[0022] In some implementations, the treatment involves irrigating the apple plant's growing medium with a suspension of B27 bacteria. The irrigation can be performed four times, once every 10 days, with each irrigation consisting of 10 mL.

[0023] In some implementations, the treatment involves irrigating the Arabidopsis seedling substrate with a suspension of B27 bacteria. The irrigation can be performed three times a week, with each irrigation consisting of 10 mL.

[0024] The above-mentioned promotion of plant growth and development includes regulating plant root system architecture (such as root hairs, lateral roots, and taproot), increasing plant height, and increasing plant fresh weight.

[0025] The regulation of plant root architecture is manifested in any one of the following X1)-X6): X1) Increase the number of lateral roots in plants; X2) Increases the root surface area of ​​plants; X3) Increases the number of plant root tips; X4) Increases the length of plant root hairs; X5) Increases the number of plant root hairs; X6) Reduce the length of the plant's taproot (or inhibit the extension of the plant's taproot).

[0026] The increase in plant fresh weight is manifested in any one of the following Y1)-Y2): Y1) Increases the fresh weight of the aboveground parts of the plant; Y2) Increases the fresh weight of the underground parts of plants.

[0027] The improvement of plant drought resistance described above is manifested in increasing the chlorophyll content of plants under drought conditions.

[0028] The promotion of plant phosphorus absorption described above is manifested in increasing the phosphorus content (inorganic phosphorus content) of plants.

[0029] The plant mentioned above is any of the following: B1) Dicotyledons; B2) Plants of the Solanaceae family, Brassicaceae family, or Rosaceae family; B3) Plants of the genera *Nicotiana*, *Arabidopsis*, or *Malus*; B4) Tobacco, Arabidopsis, or apple.

[0030] In some implementations, the tobacco is Benzoic tobacco.

[0031] In some implementations, the Arabidopsis thaliana is the Colombian ecotype.

[0032] In some implementations, the apple is the rootstock of the Pingyi sweet tea apple.

[0033] This invention demonstrates through experiments using B27 inoculated tobacco that, compared to the control group, the taproot extension of tobacco seedlings in the B27 inoculated group was inhibited, while the number of lateral roots, root hair length, aboveground fresh weight, and underground fresh weight were all significantly increased. Experiments using B27 inoculated apple rootstock showed that, compared to the control group, the plant height, aboveground fresh weight, root surface area, number of root tips, root hair length, root hair quantity, and phosphorus content of apple plants in the B27 inoculated group were all significantly increased. Experiments using B27 inoculated Arabidopsis showed that, compared to the control group, the drought resistance of Arabidopsis seedlings in the B27 inoculated group was significantly improved. These results indicate that the *Bacillus thaliana* provided in this invention... Altitude Bacillus B27 has the functions of phosphorus solubilization, promoting plant growth and phosphorus absorption, and improving plant drought resistance.

[0034] Preservation Instructions Strain name: Bacillus hygroscopicus Latin name: Altitude Bacillus Strain number: B27 Preservation Institution: China General Microbiological Culture Collection Center, China Microbiological Culture Collection Committee Collection institution abbreviation: CGMCC Address: No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing Deposit date: December 3, 2025 CGMCC Registration Number: CGMCC No. 36877 Attached Figure Description Figure 1 Detection of phosphate-solubilizing ability of rhizosphere microorganisms in apple rootstock *Malus spectabilis*. A: Schematic diagram of phosphate-solubilizing bacteria producing phosphate-solubilizing zones on *Mongina* organic phosphorus medium; B: Quantitative determination of phosphate solubility.

[0035] Figure 2 Highland Bacillus Altitude Bacillus Morphology and growth characteristics of strain B27. A: Bacillus hygroscopicus. Altitude Bacillus Colony morphology of B27 on solid culture medium; B: Bacillus hygroscopicus Bacillus height Morphological image of B27 under a microscope; C: Bacillus hygroscopicus Altitude Bacillus Microbial growth curve of B27.

[0036] Figure 3 Highland Bacillus Altitude Bacillus Phenotypic and physiological parameters of B27-inoculated *Nicotiana benthamiana* plants. AB: Inoculated (B) and uninoculated (A) *Bacillus hygroscopicus*. Altitude Bacillus Phenotypic diagram of the effect of B27 on the growth and development of Tobacco Benzoenta plants; CD: Bacillus hygroscopicus inoculated (D) and uninoculated (C) Bacillus height Phenotypic diagram of root hair development in *Nicotiana benthamiana* using B27; EH: inoculated and uninoculated with *Bacillus glaber*. Bacillus height Effects of B27 on the aboveground fresh weight (E), underground fresh weight (F), taproot length (G), and number of lateral roots (H) of Nicotiana benthamiana.

[0037] Figure 4 Highland Bacillus Altitude Bacillus Phenotypic and physiological indicators of B27 apple rootstock-grafted Pingyi sweet tea plants were analyzed. AC: Inoculation and non-inoculation with *Bacillus hygroscopicus*. Altitude Bacillus Phenotypic diagram of Pingyi sweet tea plants on apple rootstock B27; D: Inoculated and uninoculated with Bacillus hygroscopicus. Altitude Bacillus Phenotypic diagram of root hairs on B27 apple rootstock, Pingyi sweet tea; EL: inoculated and uninoculated with Bacillus hygroscopicus. Altitude BacillusThe following parameters were measured for the plant height (E), aboveground fresh weight (F), taproot length (G), underground fresh weight (H), root surface area (I), root volume (J), number of root tips (K), and plant phosphorus content (L) of the apple rootstock B27, *Pingyi sweet tea*. In AC, Bar = 5 cm; in D, Bar = 0.5 mm.

[0038] Figure 5 Highland Bacillus Altitude Bacillus B27 showed relief of drought stress after inoculation with Arabidopsis thaliana. A: Inoculation with Bacillus subtilis. Altitude Bacillus Phenotypic diagram of Arabidopsis thaliana under drought stress (B27); B: Arabidopsis thaliana inoculated with Bacillus subtilis under drought stress. Altitude Bacillus The SPAD value of leaf chlorophyll in B27. Detailed Implementation

[0039] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way.

[0040] Unless otherwise specified, the experimental methods in the following embodiments are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following embodiments are commercially available. Unless otherwise specified, the experimental methods in the following embodiments are performed at least three times.

[0041] The following is a method for preparing LB solid culture medium (1L) in the following examples: Take 10g peptone, 5g yeast extract, 10g NaCl, and 15g agar powder, dissolve them in deionized water and bring the volume to 1L, then sterilize at 121℃ for 20 min.

[0042] The following is a method for preparing LB liquid culture medium (1L) in the following examples: Take 10g peptone, 5g yeast extract, and 10g NaCl, dissolve them in deionized water and bring the volume to 1L, then sterilize at 121℃ for 20 min.

[0043] The following is a method for preparing the Monkina organophosphate medium (1L) in the following examples: Take 10g glucose, 0.5g (NH4)2SO4, 0.3g NaCl, 0.3g KCl, 0.03g FeSO4·7H2O, 0.03g MnSO4·4H2O, 0.3g MgSO4·7H2O, 0.4g yeast powder, 15g agar powder and 2g phytate (calcium phytate), dissolve and bring the volume to 1L with deionized water, adjust the pH to 7.0, and sterilize at 121℃ for 20 min.

[0044] Example 1: Bacillus subtilis Altitude Bacillus Isolation, Identification and Preservation of B27 Strain I. Isolation and Purification of Phosphate-Solubilizing Bacteria Using a dilution coating method, iron-rich apple rootstock, Malus spectabilis (Malus spectabilis), was applied. Apple tree xiaojinensis Rhizosphere soil suspensions were spread onto Monkina organic phosphorus medium with calcium phytate as the sole phosphorus source and incubated at 37°C for 3-5 days. Single colonies that produced transparent phosphate-solubilizing zones were selected and purified by repeated streaking on LB solid medium, yielding 11 pure cultures (numbered #3, #4, #9, #11, #20, #21, #22, #24, #27, #29, and #30).

[0045] II. Identification of strain B27 1. Determination of phosphorus solubility Eleven pure cultures of bacterial strains were inoculated into LB liquid medium and cultured on a shaker at 200 rpm for 14 h to obtain corresponding bacterial solutions. These solutions were then inoculated onto Monkina organic phosphorus agar plates and incubated upside down at 37°C for 2-3 days. The phosphorus solubilization ability of the strains was observed and photographed. Each strain was repeated 3 or 4 times. Through observation of the phosphorus solubilization zone and measurement of the phosphorus solubilization rate, it was found that strain #27 exhibited a larger phosphorus solubilization zone and a higher phosphorus solubilization rate. Figure 1 (Table 1) indicates that it performs well in terms of phosphorus solubility.

[0046] Table 1. Detection data on the phosphate-solubilizing ability of phosphate-solubilizing bacteria

[0047] 2. Morphological identification Strawberry strain #27 was spread onto LB solid medium using a zigzag pattern and incubated upside down in a 37°C incubator for 12 hours. The morphological characteristics of the colonies were then observed. Further, a portion of the cultured strain was picked from the colonies and placed in a 1.5 mL centrifuge tube containing 1 mL of LB liquid medium. The tube was incubated at 28°C in a shaker for 12 hours. The bacterial culture was then aspirated and observed under a regular microscope to determine the bacterial morphology.

[0048] The colony morphology of strain #27 on LB solid medium is shown in the figure below. Figure 2 As shown in Figure A, morphological observation revealed that the colony edges of strain #27 exhibited a serrated pattern, indicating the presence of a distinct biofilm. Furthermore, conventional microscopic observation revealed that the strain's morphology was rod-shaped. Figure 2 B). The microbial growth curve of strain #27 is shown below. Figure 3 As shown in C.

[0049] 3. Molecular identification Genomic DNA was extracted from strain #27 and amplified by PCR using primers 27F and 1492R to obtain the PCR product. The primer sequences are as follows: 27F: 5'-AGAGTTTGATCCTGGCTCAG-3'.

[0050] 1492R: 5'-TACCTTGTTACGACTT-3'.

[0051] PCR products were subjected to electrophoresis. After passing the test, the samples were sent to Beijing Ruiboxingke Biotechnology Co., Ltd. for 16S rRNA sequencing analysis. Sequencing results showed that the 16S rRNA sequence of strain #27 is shown in Sequence 1. Sequence alignment analysis identified strain #27 as belonging to the genus *Bacillus*. Bacillus Highland Bacillus Altitude Bacillus And named it B27.

[0052] III. Highland Bacillus Altitude Bacillus B27 Preservation Strain B27 was deposited on December 3, 2025, at the China General Microbiological Culture Collection Center (CGMCC, No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences, 100101, China), and its taxonomical name is *Bacillus hygroscopicus*. Altitude Bacillus The accession number is CGMCCNo.36877.

[0053] Example 2, Bacillus subtilis Altitude Bacillus Preparation of B27 bacterial agent 1. Activation of the strain Bacillus subtilis Altitude Bacillus B27 CGMCC No.36877 strain was inoculated onto LB solid medium and cultured in a 37°C incubator for 12 hours to obtain the activated strain.

[0054] 2. Xiaoyao After activation, the strain was picked and placed in a 1.5 mL centrifuge tube containing 1 mL of LB liquid medium. The culture was then incubated in a shaker at 37 °C for 12 h to obtain the bacterial culture after shaking.

[0055] 3. Big Shake Pour the bacterial culture after small shaking into a 100mL Erlenmeyer flask containing 50mL of LB liquid medium and incubate in a shaker at 37℃ for 12h to obtain the bacterial culture after large shaking.

[0056] 4. Adjusting the OD of the bacterial solution Transfer the shaken bacterial culture to a 50 mL centrifuge tube and centrifuge at 6000 rpm for 6 min. After centrifugation, discard the supernatant and collect the bacterial pellet. Resuspend the bacterial pellet in deionized water and adjust the OD of the bacterial culture using a spectrophotometer. 600nm =0.6, to obtain B27 bacterial suspension, which is the bacterial agent used for seedling treatment.

[0057] Example 3: Highland Bacillus Altitude Bacillus Effects of B27 on tobacco root architecture and growth Tobacco (Nicotiana benthamiana) seedlings (same age, 7 days old) grown in normal MS medium were inoculated with 100 μL of the B27 bacterial suspension prepared in Example 2 (B27 inoculation group). The inoculation method was as follows: the B27 bacterial suspension was evenly spread on the MS medium (approximately 3 / 4 of the entire square medium) using a spreading stick, and then the seedlings were transferred to the boundary. The inoculation was performed only once, and the seedlings were then placed under normal light conditions for cultivation. An equal volume of sterile water was used as a control group. After 21 days of cultivation, the growth phenotypes of the tobacco plants and root hairs were observed, and the aboveground fresh weight, underground fresh weight, taproot length, and number of lateral roots were recorded.

[0058] The results are as follows Figure 3 As shown in Table 2, the results indicate that, compared with the control group, the extension of the taproot of tobacco seedlings in the B27 inoculation group was inhibited, but the number of lateral roots and the length of root hairs increased, and the aboveground growth was more vigorous.

[0059] Table 2. Phenotypic data of tobacco plants inoculated with Bacillus hygroscopicus B27

[0060] Example 4: Bacillus subtilis Altitude Bacillus Effects of B27 on growth, development and phosphorus absorption of apple rootstock Pingyi sweet tea Seeds of Pingyi sweet tea (a type of apple rootstock) were washed and stratified in a 4°C refrigerator for approximately 40 days until germination, at which point they were planted in nutrient soil. About two weeks later, plants of uniform size and growth were selected and transplanted into the nutrient soil. After a one-week recovery period, the nutrient soil was irrigated with the B27 bacterial suspension prepared in Example 2, once every 10 days for a total of four irrigations, each time using 10 mL. Forty days after B27 inoculation, the growth phenotype of the plants and root hairs was observed and photographed. Simultaneously, plant height, aboveground fresh weight, taproot length, underground fresh weight, root surface area, root volume, number of root tips, and phosphorus content (total phosphorus content of the plant, including both aboveground and underground parts) were measured. An equal volume of sterile water was used as a control group. The phosphorus content was determined according to the method described in the literature "Peng Xiaoxia et al., A rapid and simple method for extracting multiple elements from plant samples using hydrochloric acid, Analytical Instruments, 2008, No. 4".

[0061] The results are as follows Figure 4As shown in Table 3, the results indicated that, compared with the control group, the B27 inoculated group of *Pingyi sweet tea* apples exhibited significantly increased plant height and above-ground fresh weight. Root scanning analysis revealed no significant changes in taproot length, root fresh weight, and root volume, but a significant increase in root surface area and root tip number. Microscopic examination also revealed a significant increase in root hair length and quantity. Furthermore, ICP-MS analysis showed a significant increase in phosphorus content in the B27 inoculated group compared to the control group.

[0062] Table 3. Phenotypic data of apple plants inoculated with Bacillus hygroscopicus B27

[0063] Example 5: Highland Bacillus Altitude Bacillus The effect of B27 on drought resistance in Arabidopsis thaliana Arabidopsis thaliana (Columbia ecotype) seeds were sown in sterilized nutrient soil. After true leaves emerged, seedlings of uniform size were selected for transplanting. After transplanting, the seedlings were divided into two groups according to different treatment methods: Group B27: After transplanting, water the soil with B27 bacterial suspension once a week for a total of 3 times, with each watering being 10 mL. Stop watering and allow the soil to dry naturally for 3 weeks.

[0064] Control group: After transplanting, the soil was watered with the same amount of sterile water as the "dry treatment + B27 group", once a week for a total of 3 times, with each watering being 10 mL. Additional watering was then stopped, and the plants were allowed to dry naturally for 3 weeks.

[0065] Observe the phenotypes of each group, take photos, and test the chlorophyll content of the leaves (based on SPAD-502 to determine the SPAD value of leaf chlorophyll).

[0066] The results are as follows Figure 5 As shown in the results, the Arabidopsis thaliana inoculated with B27 exhibited vigorous growth, while the plants in the control group showed relatively weak growth. Furthermore, the chlorophyll SPAD value of the B27 inoculated group was significantly higher than that of the control group. These results indicate that B27 bacterial suspension can improve plant drought resistance.

[0067] The present invention has been described in detail above. For those skilled in the art, the invention can be practiced in a wide range of ways with equivalent parameters, concentrations, and conditions without departing from its spirit and scope, and without requiring unnecessary experiments. Although specific embodiments have been given, it should be understood that further modifications can be made to the invention. In summary, according to the principles of the invention, this application is intended to include any changes, uses, or improvements to the invention, including changes made using conventional techniques known in the art that depart from the scope disclosed herein. Some of the essential features can be applied within the scope of the following appended claims.

Claims

1. Highland Bacillus Bacillus altitudinis Its features are: The Highland Bacillus Bacillus altitudinis Highland Bacillus Bacillus altitudinis Strain B27 has the registration number CGMCCNo.36877 at the China General Microbiological Culture Collection Center.

2. Containing the Bacillus hygroscopicus of claim 1 Bacillus altitudinis Combinations of or their descendants.

3. The composition according to claim 2, characterized in that: The composition is a culture; the culture is composed of the *Bacillus hygroscopicus*. Bacillus altitudinis Substances obtained by culturing their offspring in a microbial culture medium.

4. The composition according to claim 2, characterized in that: The composition is a microbial agent, a microecological preparation, or a bio-fertilizer.

5. The composition according to claim 4, characterized in that: The composition has at least one of the following properties: A1) Phosphorus solubilization; A2) Promotes plant growth and development; A3) Improve plant drought resistance; A4) Promotes phosphorus absorption by plants.

6. The composition according to claim 5, characterized in that: The plant is any one of the following: B1) Dicotyledons; B2) Plants of the Solanaceae family, Brassicaceae family, or Rosaceae family; B3) Plants of the genera *Nicotiana*, *Arabidopsis*, or *Malus*; B4) Tobacco, Arabidopsis, or apple.

7. The Bacillus hygroscopicus of claim 1 Bacillus altitudinis The use of the composition thereof or its derivatives or any of claims 2-6 in any of the following: C1) Phosphorus solubilization; C2) Preparation of phosphorus-solubilized products; C3) Promotes plant growth and development; C4) Prepare products that promote plant growth and development; C5) Improves plant drought resistance; C6) Prepare products that improve plant drought resistance; C7) Promotes phosphorus absorption in plants; C8) to prepare products that promote phosphorus absorption in plants.

8. The application according to claim 7, characterized in that: The plant is any one of the following: B1) Dicotyledons; B2) Plants of the Solanaceae family, Brassicaceae family, or Rosaceae family; B3) Plants of the genera *Nicotiana*, *Arabidopsis*, or *Malus*; B4) Tobacco, Arabidopsis, or apple.

9. A method for promoting plant growth and development, improving plant drought resistance, or promoting plant phosphorus absorption, comprising the following steps: using the *Bacillus hygroscopicus* as described in claim 1. Bacillus altitudinis The composition thereof or its derivatives or any of claims 2-6 is used to treat the roots of the plant to be treated or its growth substrate, thereby promoting plant growth and development, improving plant drought resistance, or promoting plant phosphorus absorption.

10. The method according to claim 9, characterized in that: The plant is any one of the following: B1) Dicotyledons; B2) Plants of the Solanaceae family, Brassicaceae family, or Rosaceae family; B3) Plants of the genera *Nicotiana*, *Arabidopsis*, or *Malus*; B4) Tobacco, Arabidopsis, or apple.

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