Saline-alkali soil plant growth promoting paenibacillus and application thereof

Abstract

The invention relates to the field of microbial technology and ecological restoration of saline-alkali soil, in particular to plant growth-promoting paenibacillus for saline-alkali soil and application of the plant growth-promoting paenibacillus. The microbial inoculum comprises paenibacillus sp. XJ-1, P.megatherium Y-39, Endophytic glutamicum G-30 and Enterobacter C-29, and is prepared by mixing the paenibacillus sp. XJ-1, the P.megatherium Y-39, the Endophytic glutamicum G-30 and the Enterobacter C-29 according to a ratio of 1: 1: 1: 1: 1 and carrying out co-culture domestication, function synergistic induction and adaptability synchronous reinforcement. The viable count of the microbial agent is larger than or equal to 1 * 10 cfu / mL, the microbial agent can tolerate 15% NaCl, the pH value of the microbial agent is 9.5, the pH value of soil can be remarkably reduced through root irrigation or seed dressing application, the soil enzyme activity and the crop biomass can be improved, and the microbial agent is suitable for saline-alkali soil crops such as oilseed rape and wheat, has the advantages of being high in stress tolerance, synergistic in function, safe in ecology and the like and has wide application prospects.

Description

Technical Field

[0001] The present invention relates to the fields of microbial technology and saline-alkali land ecological restoration, and in particular to a saline-alkali land plant growth-promoting Paenibacillus sp. and applications thereof. Background Art

[0002] Soil salinization is one of the biggest constraints on crop production. Saline soil has the characteristics of high electrical conductivity, low water potential, and excessive ionic salt. Most plants find it difficult to survive. Land salinization seriously affects the growth and development of plants, reducing plant biomass and yield. Neutral salt stress in plants is mainly caused by NaCl and Na2SO4. Neutral saline-alkali stress triggers plant ion imbalance, leading to nutrient deficiency, disordered carbon and nitrogen assimilation pathways, reduced photosynthesis rate, excessive generation of reactive oxygen species (ROS), and osmotic and oxidative stress, resulting in crop growth stunting and reduced yield. Salt and alkali also have a negative impact on the soil formation process, pH value, nutrient composition, decomposition rate, microbial diversity and water availability, thus causing saline-alkali stress and drought stress to plants.

[0003] Salt-alkali stress is mainly caused by Na2CO3, which includes Na + Poisoning and HCO3 - or CO3 2- The main anion poisoning is Na + Excessive concentrations cause ion concentration and potential differences to form inside and outside the plant cell membrane. + Inflow and K + The balance is destroyed by efflux, causing Na + Toxic, causing cell damage. + Ca bound to cell membranes 2+ Forming a competitive effect, resulting in Ca 2 + The concentration decreases and the membrane system is damaged. - or CO3 2- This can alter the soil's pH and colloidal structure, affecting plant absorption of carbon, nitrogen, iron, phosphorus, and other elements. Existing technologies include physical amendments, which are costly and disrupt soil microbial homeostasis. Chemical amendments can easily cause secondary contamination. Single microbial agents often have limited growth-promoting effects in highly saline and alkaline environments due to their limited functionality and lack of salt tolerance.

[0004] Plant growth-promoting rhizobacteria (PGPR) promote plant growth through phosphate solubilization, nitrogen fixation, secretion of the auxin IAA, and production of ACC deaminase. However, their application under saline-alkali stress is limited by strain tolerance and functional synergy. For example, a single strain may only be capable of phosphate solubilization or IAA production, while antagonistic interactions between strains in a composite microbial agent can reduce its effectiveness. Therefore, screening for strain combinations with strong salt tolerance, complementary functions, and no antagonism is key to improving saline-alkali land.

[0005] Therefore, based on the above-mentioned related technologies, there is an urgent need to develop a saline-alkali soil plant growth-promoting Bacillus and its application. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to propose a saline-alkali land plant growth-promoting Bacillus and its application, so as to solve the problems of limited function and insufficient salt tolerance of single bacterial agents in the existing technology, and to provide a composite bacterial agent with strong salt tolerance and synergistic functions to achieve the dual effects of saline-alkali land soil improvement and crop growth promotion.

[0007] Based on the above objectives, the present invention provides a saline-alkali soil plant growth-promoting Paenibacillus sp. and its application.

[0008] A bacillus sporogenes for promoting plant growth in saline-alkali soil comprises a bacillus mixture and a compound bacteria mixture.

[0009] Preferably, the preparation process of the saline-alkali soil plant growth-promoting Paenibacillus is as follows: Step S1. Co-culture acclimation; Step S2. Functional synergistic induction; Step S3: Adaptive synchronization reinforcement.

[0010] Preferably, the co-cultivation acclimation process in step S1 is as follows: Step S101. Single bacteria pretreatment; Step S102: Gradient co-culture acclimation.

[0011] Preferably, the process of single bacteria pretreatment in step S101 is as follows: Priesteria gigantea, endophytic glutamicum and Enterobacter were cultured to the logarithmic phase (OD 600 ≈0.8), the cells were collected by centrifugation, washed twice with sterile saline, and resuspended in a buffer solution containing 5% saline-alkali rhizosphere extract.

[0012] Preferably, the gradient co-culture acclimation process in step S102 is as follows: Step S1021. Generations 1-5: Add 10% sterile filtrate of Bacillus subtilis filtered through a 0.22 μm filter to the basal medium of Priesteria megaterium, endophytic glutamicum, and Enterobacter, incubate at 30°C and 180 rpm, and subculture once every 24 hours to gradually adapt to each other's metabolites. Step S1022. Generations 6-10: Increase the concentration of the Bacillus subtilis filtrate to 30%, simultaneously reduce the proportion of the single carbon source, and add 0.5% betaine (a characteristic osmoprotectant for saline-alkali soils) to induce metabolic synergy; Step S1023. Generations 11-15: Priesteria megaterium, endophytic Bacillus glutamicum, Enterobacter, and Bacillus subtilis were mixed in a ratio of 1:1:1:1, using saline-alkali soil extract with a pH of 9.0 and a salt content of 5 g / kg as the sole culture medium. The dominant coexistence system was screened by plate count method to ensure that the survival rate of each bacteria was ≥85%.

[0013] Step S1024. The cross-hatch method was used to detect that there was no inhibition zone on the same plate after the acclimation of the strain, indicating that the antagonistic effect was eliminated. After 72 hours of mixed culture, the total number of viable bacteria increased by 40% compared with that before acclimation.

[0014] Preferably, the Priesteria gigantea in step S1021 is Priesteria gigantea Y-39, and the screening process of the Priesteria gigantea Y-39 is as follows: Weigh 10 g of saline-alkali reed rhizosphere soil sample with a pH of 9.0-9.5 and a salt content of 5-8 g / kg, add 90 mL of sterile water containing 10% NaCl, shake for 30 min, and bathe in 80 °C water for 10 min to remove non-spore-forming bacteria, and then dilute to 10 -6 , the silicate phosphate-solubilizing medium (sodium silicate 5 g / L + glucose 10 g / L) containing 10% NaCl was shake-cultured at 37°C for 48 h to selectively enrich the salt-tolerant silica-solubilizing strains, and then spread on a TSA plate (tryptone 15 g / L + soy peptone 5 g / L + NaCl 100 g / L) containing 10% NaCl and cultured at 37°C for 24 h. The single colony with a transparent circle around the colony was picked to obtain Priesterla gigantea Y-39.

[0015] Preferably, the endophytic glutamicum bacteria is endophytic glutamicum bacteria G-30, and the screening process of the endophytic glutamicum bacteria G-30 is as follows: The rhizosphere soil of saline-alkali land with a pH of 8.5-9.0 and a salt content of 3-5 g / kg was used as the source, and the culture medium was Montgina inorganic phosphorus medium (containing 5 g / LCa3 (PO4)2) + 5% NaCl + 50 μg / mL tetracycline (for fungal inhibition) and cultured at 30 ° C for 72 h. 10 mmol / L NaHCO3 was added and HCO3 was used. -stress, selectively enrich the alkali-resistant phosphate-solubilizing strains, then pick the colonies with the transparent circle (D / d ≥ 1.8) after coating the plates, inoculate them into urease medium (containing 10 g / L urea), culture at 30 ° C for 48 h, and screen the strains with urease activity ≥ 40 U / mL by sodium phenol colorimetry to obtain endophytic glutamicum Bacillus G-30.

[0016] Preferably, the Enterobacter is Enterobacter C-29, and the screening process of Enterobacter C-29 is as follows: The rhizosphere soil sample with a salt content of 8-10 g / kg and a pH of 9.5 was used as the source. LB medium containing 12.5% ​​NaCl + 0.1% calcium phytate (organic phosphorus source) was used as the culture medium. The culture was anaerobically cultured at 37°C for 48 h. The Montgena organophosphate medium transparent circle method was used to pick colonies with D / d ≥ 2.0. HPLC determination of soluble phosphorus ≥ 30 μg / mL was performed. The iron carrier was detected by CAS method, As / Ar ≤ 0.1. Salt tolerance was verified using 12.5% ​​NaCl medium, and OD was obtained. 600 ≥0.6, that is, Enterobacter C-29 is obtained.

[0017] Preferably, the Paenibacillus is Paenibacillus XJ-1, and the screening process of the Paenibacillus XJ-1 is as follows: Rhizosphere soil samples of alkaline desert Althaea thornii with a pH of 9.5 and a salt content of 10 g / kg were used as the source. The soil samples were suspended in 10% NaCl solution and incubated in an 80°C water bath for 20 min to kill vegetative cells and enrich spores. High-salt medium (10% NaCl) containing 5 g / L lecithin was used for primary screening to select bifunctional strains that could solubilize phosphate (transparent circle) and produce IAA (red by Salkowski color development). ACC deaminase activity (≥20 U / mg) was measured under saline-alkali stress (15% NaCl + pH 9.5) for secondary screening. A stress-resistant strain, namely Paenibacillus sp. XJ-1, was obtained.

[0018] Preferably, the process of functional synergistic induction in step S2 is as follows: Step S201. Adding 0.1 mmol / L of phosphoenolpyruvate to the culture medium of Priesteria megaterium and Enterobacter to induce the expression of genes involved in phosphate solubilization and promote metabolic coupling with nitrogen fixation genes of Bacillus subtilis, thereby increasing the combined nitrogen-phosphorus conversion efficiency by 25%. Adding 10 μmol / L of 1-aminocyclopropane-1-carboxylic acid to the culture medium of endophytic Bacillus glutamicum to induce the production of ACC deaminase, thereby jointly reducing ethylene accumulation in plant roots. Step S202. Add 2mmol / LCa to the culture medium at the late stage of acclimation 2+and 0.1% humic acid, promoted the strains to secrete extracellular polysaccharides and lipopeptides, and increased the biofilm formation of the four bacteria by 53%. The biofilm can enhance the adsorption ability of the strains on the root surface.

[0019] Preferably, the process of adaptive synchronization reinforcement in step S3 is as follows: Step S301. Salt-alkali gradient acclimation: Priesteria gigantea, endophytic glutamicum, and Enterobacter were serially passaged in a gradient medium containing 8%-15% NaCl and a pH of 8.5-9.5, increasing the NaCl concentration by 0.5% or the pH by 0.2 units each generation. Ultimately, at 15% NaCl and a pH of 9.5, the survival rate increased from an initial 35% to 78%, closely matching the stress tolerance range of Bacillus subtilis. Step S302. Metabolite cross-protection: Metabolite fluids from Bacillus subtilis grown in a high-salt environment containing osmotic protectants such as proline and betaine are collected and used to culture Priesteria gigantea, endophytic glutamicum, and Enterobacter, inducing them to accumulate compatible solutes and enhancing the cells' ability to regulate osmotic pressure. The intracellular ATP content under saline-alkali stress is 32% higher than that of the untreated group.

[0020] An application of a bacillus for promoting plant growth in saline-alkali soil, wherein the bacillus for promoting plant growth in saline-alkali soil is used in a rapeseed field, and the specific process is as follows: Step T1. Soil pretreatment (20 days before sowing): Salt-alkali regulation: For severely saline-alkali land with pH>9.0, spread humic acid (200kg / mu) + gypsum (50kg / mu) 15 days in advance, till the soil to 20cm and mix to reduce the exchangeable sodium content; Activation of the microbial agent: The prepared saline-alkali soil plant growth-promoting Paenibacillus microbial agent (1:1:1:1 mixture) was mixed with the saline-alkali soil extract (salt content 5g / kg + pH 9.0) in a ratio of 1:10, and cultured at 30°C with shaking for 24h. The number of viable bacteria was increased to 2×10 9 CFU / mL; Mixed basal fertilizer application: Mix activated microbial agent (2L / mu) with decomposed sheep manure (1.5 tons / mu) and superphosphate (30kg / mu), spread and till the soil 15cm deep to form a microorganism-organic fertilizer composite layer; Step T2. Intensive application during key growth period: Seedling stage (4-5 leaves): Dilute the inoculant: Take 2 mL / kg of the prepared saline-alkali soil plant growth-promoting Paenibacillus inoculant stock solution and add 5 times the volume of saline-alkali soil extract (8% salt content + pH 9.5) to prepare 10 mL / kg of root irrigation solution; Precision root irrigation: Drill holes 5 cm around the rapeseed root system (8-10 cm deep), inject 100 mL of root irrigation solution into each plant, and simultaneously drip irrigate with 0.5% humic acid solution (50 L / mu) to promote establishment; Bolting stage (stem height 10-15cm): foliar spray: dilute the agent to 1×10 8 CFU / mL, add 0.1% alginic acid + 0.05% ammonium molybdate, spray evenly in the evening on a sunny day (water consumption 40L / mu), focusing on the back of leaves and stems; Rhizosphere supplementation: Combined with tillage and soil loosening, apply the bacterial agent-biochar complex (bacterial agent 1L / mu + biochar 50kg / mu) in a ring ditch at the base of the plant, cover with soil and water 5cm.

[0021] Step T3. Post-harvest restoration: When returning straw to the field, spray the bacterial agent concentrate on the crushed straw at a ratio of 1:100 and press it into the soil to promote the formation of saline-alkali soil aggregates (stability increased by 29%).

[0022] An application of a bacillus for promoting plant growth in saline-alkali soil, wherein the bacillus for promoting plant growth in saline-alkali soil is used in a wheat field, and the specific process is as follows: Step U1. Co-processing during the sowing period: Seed coating: Mix the prepared saline-alkali soil plant growth-promoting Paenibacillus agent stock solution (2 mL / kg seed) with 0.5% chitosan solution, mix with seeds, dry in the shade and then sow; Soil inoculation: Three days before sowing, mix the prepared saline-alkali soil plant growth-promoting Paenibacillus agent (2L / mu) with 20kg / mu of decomposed fungus residue (a byproduct of Bacillus subtilis fermentation) and evenly inject it into the 0-20cm soil layer along with bottom water (50m³ / mu) through a drip irrigation system to promote rhizosphere colonization. Step U2. Dynamic Regulation of Growth Period: Tillering Period (30-40 days after emergence): Root irrigation scheme: 2 mL / kg of the prepared saline-alkali soil plant growth-promoting Paenibacillus inoculant stock solution was diluted in a 10% saline solution (containing 0.5% betaine + 0.1% CaCl2). Furrows (10 cm deep) were dug along the sowing rows for irrigation, and then the soil was covered with film to increase temperature and retain moisture. Foliar supplementation: When spraying imidacloprid to prevent aphids, add the diluted bacterial agent (1×10 8 CFU / mL), achieving the synergy of “insect prevention + growth promotion”; Greening period (mid-March): Combine microbial agent and fertilizer application: Dissolve microbial agent (1L / mu) with urea (15kg / mu) and potassium dihydrogen phosphate (5kg / mu) in irrigation water (30m³ / mu) and apply through the sprinkler irrigation system, while simultaneously lowering the soil pH by 0.8-1.0 units; Biological regulation: spraying 0.1mmol / L salicylic acid solution (30L / mu) to induce wheat systemic resistance and enhance the growth-promoting effect of the microbial agent; Step U3. Stress resistance strengthening during grouting period: Microbial agent-micro fertilizer composite spraying: dilute the microbial agent to 1×10 7 CFU / mL, add 0.2% zinc sulfate + 0.1% borax, spray 7 days after flowering (water consumption 45L / mu), can increase the thousand-grain weight by 3-5g; Root protection: In the late filling stage, use a diluted solution of a 12% salt-containing bacterial agent (2 mL / kg soil) for foliar fertilization, combined with drip irrigation of 0.3% potassium humate (20 L / mu) to alleviate premature aging caused by salt stress.

[0023] Beneficial effects of the present invention: The present invention provides a saline-alkali soil plant growth-promoting Paenibacillus and its application. The saline-alkali soil plant growth-promoting Paenibacillus provided by the present invention has the following advantages: Outstanding stress resistance: Through salt-alkali gradient acclimation and metabolite protection, the bacterial agent can survive more than 75% in an environment of 15% NaCl and pH 9.5, solving the problem of insufficient salt tolerance of existing bacterial agents.

[0024] Functional synergy: The four strains have the functions of solubilizing phosphate, producing IAA, increasing urease activity, and producing siderophores. After induction, the combined phosphate solubilization ability is increased by 30%, and the nitrogen-phosphorus conversion efficiency is 1.5 times that of the existing single bacterial agent.

[0025] Significant soil improvement: Continuous application can reduce soil pH by 0.7-0.8 units, increase urease and sucrase activities by 40%-60%, increase the proportion of aggregates >0.25mm by 28%, and improve soil structure and fertility.

[0026] Highly effective in promoting crop growth: the above-ground fresh weight of rapeseed and the thousand-grain weight of wheat increased by 110%-130% compared with the control, the MDA content in leaves decreased by 57%, and the SOD activity increased by 72%, thereby enhancing crop stress resistance and yield.

[0027] High ecological safety: Pure microbial compound, no chemical residue, can increase soil microbial diversity, avoid secondary pollution, and meet the needs of green agricultural development. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to specific embodiments.

[0029] Example 1: A method for preparing a saline-alkali soil plant growth-promoting bacillus, comprising the following steps: S1. Weigh 10 g of saline-alkali reed rhizosphere soil sample with a pH of 9.0 and a salt content of 5 g / kg, add 90 mL of sterile water containing 10% NaCl, shake for 30 minutes, and bathe in 80°C water for 10 minutes to remove non-spore-forming bacteria. Then, dilute the sample to 10 -6, a silicate phosphate-solubilizing medium (5 g / L sodium silicate + 10 g / L glucose) containing 10% NaCl was shake-cultured at 37°C for 48 h to selectively enrich salt-tolerant silica-solubilizing strains, which were then spread on TSA plates (15 g / L tryptone + 5 g / L soy peptone + 100 g / L NaCl) containing 10% NaCl and cultured at 37°C for 24 h. Single colonies with clear zones around them were picked to obtain Priesterla gigantea Y-39; S2. Using saline-alkali soil with a pH of 8.5 and a salt content of 3 g / kg of Suaeda salsa rhizosphere soil as the source, using Montgina inorganic phosphorus medium (containing 5 g / LCa3 (PO4)2) + 5% NaCl + 50 μg / mL tetracycline (for fungal inhibition) as the culture medium, cultured at 30°C for 72 h, adding 10 mmol / L NaHCO3, and using HCO3 - stress, selectively enriching alkaline phosphate-tolerant strains, then picking colonies with transparent circles (D / d ≥ 1.8) after plating on plates, inoculating them into urease medium (containing 10 g / L urea), culturing at 30°C for 48 h, and screening strains with urease activity ≥ 40 U / mL using the sodium phenol colorimetric method to obtain endophytic glutamicum Bacillus G-30; S3. Using saline rhizosphere soil samples with a salt content of 8-10 g / kg and a pH of 9.5 as the source, using LB medium containing 12.5% ​​NaCl + 0.1% calcium phytate (organic phosphorus source) as the culture medium, anaerobically cultured at 37°C for 48 h, using the Montana organophosphate medium clear zone method, picking colonies with D / d ≥ 2.0, HPLC determination of soluble phosphorus ≥ 30 μg / mL, CAS method for siderophore detection, As / Ar ≤ 0.1, using 12.5% ​​NaCl medium for salt tolerance verification, and obtaining the OD 600 ≥0.6, that is, Enterobacter C-29 is obtained; S4. Using rhizosphere soil samples from a saline-alkali desert algae thorn (Althaea thorn) with a pH of 9.5 and a salt content of 10 g / kg, the soil samples were suspended in 10% NaCl solution and incubated at 80°C for 20 min to kill vegetative cells and enrich spores. Initial screening was performed using a high-salt medium (10% NaCl) containing 5 g / L lecithin to identify strains that exhibited both phosphate solubilization (transparent zone) and IAA production (red color development using Salkowski colorimetry). Secondary screening was performed under saline-alkali stress (15% NaCl, pH 9.5) by measuring ACC deaminase activity (≥20 U / mg). A stress-resistant strain, Paenibacillus sp. XJ-1, was identified. S5. Cultivate Priesteria gigantea, endophytic glutamicum and Enterobacter to the logarithmic phase (OD 600 ≈0.8), the cells were collected by centrifugation, washed twice with sterile saline, and resuspended in a buffer solution containing 5% saline-alkali rhizosphere extract; S6. Gradient co-culture acclimation: Generations 1-5: Add 10% of the sterile filtrate of Bacillus subtilis filtered through a 0.22 μm filter membrane to the basal culture medium of Priesteria megaterium, endophytic glutamicum, and Enterobacter, culture at 30°C and 180 rpm, and subculture once every 24 hours to gradually adapt to each other's metabolites; Generations 6-10: Increase the concentration of the Bacillus subtilis filtrate to 30%, simultaneously reduce the proportion of the single carbon source, and add 0.5% betaine (a characteristic osmotic protectant for saline-alkali land) to induce metabolic coordination. Same; 11th-15th generations: Priesteria gigantea, endophytic glutamicum, Enterobacter, and Bacillus subtilis were mixed in a ratio of 1:1:1:1, using saline-alkali soil leachate with a pH of 9.0 and a salt content of 5 g / kg as the sole culture medium. The dominant coexistence system was screened by plate count to ensure that the survival rate of each bacteria was ≥85%. The cross-streaking method was used to detect the absence of inhibition zones on the same plate after acclimation, indicating that the antagonistic effect was eliminated. After 72 hours of mixed culture, the total viable bacterial count increased by 40% compared with the pre-acclimation level. S7. Add 0.1mmol / L phosphoenolpyruvate to the culture medium of Priesteria gigantea and Enterobacter to induce the expression of phosphate-solubilizing genes and promote metabolic coupling with nitrogen-fixing genes of Bacillus subtilis, thereby increasing the combined nitrogen-phosphorus conversion efficiency by 25%. Add 10μmol / L 1-aminocyclopropane-1-carboxylic acid to the culture medium of endophytic Bacillus glutamicum to induce the production of ACC deaminase, thereby jointly reducing the accumulation of ethylene in plant roots. Add 2mmol / L CaCl2 to the culture medium in the late stage of acclimation. 2+ and 0.1% humic acid, promoted the secretion of extracellular polysaccharides and lipopeptides by the strains, and increased the amount of biofilm formed by the four bacteria by 53%. The biofilm can enhance the adsorption capacity of the strains on the root surface; S8. The process of simultaneous adaptive enhancement is as follows: Salt-alkali gradient acclimation: Priesteria gigantea, endophytic glutamicum, and Enterobacter were serially passaged in a gradient culture medium containing 8%-15% NaCl and a pH of 8.5-9.5, with an increase of 0.5% NaCl or 0.2 pH units per generation. Ultimately, under the conditions of 15% NaCl and pH 9.5, the survival rate increased from the initial 35% to 78%, which is highly consistent with the stress tolerance range of Bacillus subtilis. Metabolite cross-protection: The metabolic fluid of Bacillus subtilis grown in a high-salt environment containing osmotic protectants such as proline and betaine was collected and used to culture Priesteria gigantea, endophytic glutamicum, and Enterobacter, inducing them to accumulate compatible solutes and enhancing the cell's ability to regulate osmotic pressure. The intracellular ATP content under salt-alkali stress was 32% higher than that of the untreated group.

[0030] Example 2: A method for preparing a saline-alkali soil plant growth-promoting bacillus, comprising the following steps: S1. Weigh 10 g of saline-alkali reed rhizosphere soil sample with a pH of 9.5 and a salt content of 8 g / kg, add 90 mL of sterile water containing 10% NaCl, shake for 30 minutes, and bathe in 80°C water for 10 minutes to remove non-spore-forming bacteria. Then, dilute the sample to 10 -6 , a silicate phosphate-solubilizing medium (5 g / L sodium silicate + 10 g / L glucose) containing 10% NaCl was shake-cultured at 37°C for 48 h to selectively enrich salt-tolerant silica-solubilizing strains, which were then spread on TSA plates (15 g / L tryptone + 5 g / L soy peptone + 100 g / L NaCl) containing 10% NaCl and cultured at 37°C for 24 h. Single colonies with clear zones around them were picked to obtain Priesterla gigantea Y-39; S2. The rhizosphere soil of Suaeda salsa with a pH of 9.0 and a salt content of 5 g / kg was used as the source, and the culture medium was Montgina inorganic phosphorus medium (containing 5 g / LCa3 (PO4)2) + 5% NaCl + 50 μg / mL tetracycline (for fungal inhibition) and cultured at 30°C for 72 h. 10 mmol / L NaHCO3 was added and HCO3 - stress, selectively enriching alkaline phosphate-tolerant strains, then picking colonies with transparent circles (D / d ≥ 1.8) after plating on plates, inoculating them into urease medium (containing 10 g / L urea), culturing at 30°C for 48 h, and screening strains with urease activity ≥ 40 U / mL using the sodium phenol colorimetric method to obtain endophytic glutamicum Bacillus G-30; S3. Using a saline rhizosphere soil sample with a salt content of 10 g / kg and a pH of 9.5 as the source, LB medium containing 12.5% ​​NaCl + 0.1% calcium phytate (organic phosphorus source) was used as the culture medium. Anaerobically cultured at 37°C for 48 h, the Montana organophosphate medium transparent zone method was used to pick colonies with D / d ≥ 2.0. HPLC determination of soluble phosphorus ≥ 30 μg / mL was performed, and siderophore detection was performed using the CAS method, with As / Ar ≤ 0.1. Salt tolerance was verified using 12.5% ​​NaCl medium, and the OD was obtained. 600 ≥0.6, that is, Enterobacter C-29 is obtained; S4. Using rhizosphere soil samples from a saline-alkali desert algae thorn (Althaea thorn) with a pH of 9.5 and a salt content of 10 g / kg, the soil samples were suspended in 10% NaCl solution and incubated at 80°C for 20 min to kill vegetative cells and enrich spores. Initial screening was performed using a high-salt medium (10% NaCl) containing 5 g / L lecithin to identify strains that exhibited both phosphate solubilization (transparent zone) and IAA production (red color development using Salkowski colorimetry). Secondary screening was performed under saline-alkali stress (15% NaCl, pH 9.5) by measuring ACC deaminase activity (≥20 U / mg). A stress-resistant strain, Paenibacillus sp. XJ-1, was identified. S5. Cultivate Priesteria gigantea, endophytic glutamicum and Enterobacter to the logarithmic phase (OD 600 ≈0.8), the cells were collected by centrifugation, washed twice with sterile saline, and resuspended in a buffer solution containing 5% saline-alkali rhizosphere extract; S6. Gradient co-culture acclimation: Generations 1-5: Add 10% of the sterile filtrate of Bacillus subtilis filtered through a 0.22 μm filter membrane to the basal culture medium of Priesteria megaterium, endophytic glutamicum, and Enterobacter, culture at 30°C and 180 rpm, and subculture once every 24 hours to gradually adapt to each other's metabolites; Generations 6-10: Increase the concentration of the Bacillus subtilis filtrate to 30%, simultaneously reduce the proportion of the single carbon source, and add 0.5% betaine (a characteristic osmotic protectant for saline-alkali land) to induce metabolic coordination. Same; 11th-15th generations: Priesteria gigantea, endophytic glutamicum, Enterobacter, and Bacillus subtilis were mixed in a ratio of 1:1:1:1, using saline-alkali soil leachate with a pH of 9.0 and a salt content of 5 g / kg as the sole culture medium. The dominant coexistence system was screened by plate count to ensure that the survival rate of each bacteria was ≥85%. The cross-streaking method was used to detect the absence of inhibition zones on the same plate after acclimation, indicating that the antagonistic effect was eliminated. After 72 hours of mixed culture, the total viable bacterial count increased by 40% compared with the pre-acclimation level. S7. Add 0.1mmol / L phosphoenolpyruvate to the culture medium of Priesteria gigantea and Enterobacter to induce the expression of phosphate-solubilizing genes and promote metabolic coupling with nitrogen-fixing genes of Bacillus subtilis, thereby increasing the combined nitrogen-phosphorus conversion efficiency by 25%. Add 10μmol / L 1-aminocyclopropane-1-carboxylic acid to the culture medium of endophytic Bacillus glutamicum to induce the production of ACC deaminase, thereby jointly reducing the accumulation of ethylene in plant roots. Add 2mmol / L CaCl2 to the culture medium in the late stage of acclimation. 2+ and 0.1% humic acid, promoted the secretion of extracellular polysaccharides and lipopeptides by the strains, and increased the amount of biofilm formed by the four bacteria by 53%. The biofilm can enhance the adsorption capacity of the strains on the root surface; S8. The process of simultaneous adaptive enhancement is as follows: Salt-alkali gradient acclimation: Priesteria gigantea, endophytic glutamicum, and Enterobacter were serially passaged in a gradient culture medium containing 8%-15% NaCl and a pH of 8.5-9.5, with an increase of 0.5% NaCl or 0.2 pH units per generation. Ultimately, under the conditions of 15% NaCl and pH 9.5, the survival rate increased from the initial 35% to 78%, which is highly consistent with the stress tolerance range of Bacillus subtilis. Metabolite cross-protection: The metabolic fluid of Bacillus subtilis grown in a high-salt environment containing osmotic protectants such as proline and betaine was collected and used to culture Priesteria gigantea, endophytic glutamicum, and Enterobacter, inducing them to accumulate compatible solutes and enhancing the cell's ability to regulate osmotic pressure. The intracellular ATP content under salt-alkali stress was 32% higher than that of the untreated group.

[0031] Example 3: Application of Paenibacillus sp. for promoting plant growth in saline-alkali soil. The application of Paenibacillus sp. for promoting plant growth in saline-alkali soil in rapeseed fields is as follows: S1. Soil pretreatment (20 days before sowing): Salt-alkali adjustment: For severely saline-alkali soil with a pH greater than 9.0, apply humic acid (200 kg / mu) and gypsum (50 kg / mu) 15 days in advance, plowing the soil to a depth of 20 cm to reduce the exchangeable sodium content. S2. Activation of the bacterial agent: The saline-alkali soil plant growth-promoting Paenibacillus bacterial agent prepared in Example 1 (1:1:1:1 mixture) was mixed with the saline-alkali soil extract (5 g / kg salt content + pH 9.0) in a ratio of 1:10, and cultured with shaking at 30°C for 24 h. The number of viable bacteria was increased to 2 × 10 9 CFU / mL; S3. Base fertilizer: Mix the activated microbial agent (2 L / mu) with decomposed sheep manure (1.5 tons / mu) and superphosphate (30 kg / mu). Spread the application and then till the soil 15 cm deep to form a microbial-organic fertilizer composite layer. S4. Intensive application during key growth stages: Seedling stage (4-5 leaves): Dilute the inoculant: Take 2 mL / kg of soil of the saline-alkali soil plant growth-promoting Paenibacillus inoculant prepared in Example 1 and add 5 times the volume of saline-alkali soil extract (8% salt content, pH 9.5) to prepare a 10 mL / kg root irrigation solution; S5. Precision root irrigation: Drill holes 5 cm around the rapeseed root system (8-10 cm deep) and inject 100 mL of root irrigation solution per plant. Simultaneously drip irrigate with 0.5% humic acid solution (50 L / mu) to promote establishment. S6. Bolting stage (stem height 10-15 cm): Foliar spray: dilute the agent to 1×10 8 CFU / mL, add 0.1% alginic acid + 0.05% ammonium molybdate, spray evenly in the evening on a sunny day (water consumption 40L / mu), focusing on the back of leaves and stems; S7. Rhizosphere supplementation: Combined with tillage and soil loosening, apply the bacterial agent-biochar complex (bacterial agent 1L / mu + biochar 50kg / mu) in a ring ditch at the base of the plant, cover with soil and water 5cm.

[0032] S8. Post-harvest restoration: When returning straw to the field, spray the bacterial agent concentrate on the crushed straw at a ratio of 1:100, and press it into the soil to promote the formation of saline-alkali soil aggregates (stability increased by 29%).

[0033] Example 4: Application of a bacillus sp. for promoting plant growth in saline-alkali soil. The bacillus sp. for promoting plant growth in saline-alkali soil is used in wheat fields. The specific process is as follows: S1. Co-treatment at sowing time: Seed coating: Mix the saline-alkali soil plant growth-promoting Paenibacillus inoculant solution (2 mL / kg seed) prepared in Example 2 with 0.5% chitosan solution, dry in the shade, and sow; S2. Soil inoculation: Three days before sowing, the saline-alkali soil plant growth-promoting Paenibacillus inoculant prepared in Example 2 (2 L / mu) was mixed with 20 kg / mu of decomposed fungus residue (a byproduct of Bacillus subtilis fermentation). The mixture was evenly injected into the 0-20 cm soil layer along with subsoil water (50 m³ / mu) via a drip irrigation system to promote rhizosphere colonization. S3. Dynamic Control of the Growth Period: Tillering Stage (30-40 days after emergence): Root Irrigation: 2 mL / kg of soil of the Paenibacillus spp. inoculant prepared in Example 2 was diluted with a 10% salinity-enhancing solution (containing 0.5% betaine and 0.1% CaCl2). Furrows (10 cm deep) were opened along the sown rows for irrigation, followed by mulching with film to increase temperature and retain moisture. S4. Foliar supplementation: When spraying imidacloprid to prevent aphids, add the diluted bacterial agent (1×10 8 CFU / mL), achieving the synergy of “insect prevention + growth promotion”; S5. Greening period (mid-March): Combine microbial inoculant and fertilizer application: Dissolve the microbial inoculant (1L / mu) with urea (15kg / mu) and potassium dihydrogen phosphate (5kg / mu) in irrigation water (30m³ / mu) and apply through a sprinkler irrigation system, simultaneously lowering the soil pH by 0.8-1.0 units. S6. Biological regulation: Spray 0.1mmol / L salicylic acid solution (30L / mu) to induce systemic resistance of wheat and enhance the growth-promoting effect of bacterial agents.

[0034] S7. Strengthening stress resistance during the filling period: spraying the bacterial agent and micronutrient fertilizer: dilute the bacterial agent to 1×10 7 CFU / mL, add 0.2% zinc sulfate + 0.1% borax, spray 7 days after flowering (water consumption 45L / mu), can increase the thousand-grain weight by 3-5g; S8. Root protection: In the late stage of filling, use a diluted solution of 12% salt-containing bacterial agent (2mL / kg soil) for foliar fertilization, combined with drip irrigation of 0.3% potassium humate (20L / mu) to alleviate premature aging caused by salt stress.

[0035] Comparative Example 1: Omitting the co-cultivation acclimation step: Differences from Example 1: Priesteria megaterium Y-39, endophytic Bacillus glutamicum G-30, Enterobacter C-29, and Paenibacillus XJ-1 were directly mixed at a ratio of 1:1:1:1, without gradient co-culture acclimation (i.e., no Bacillus subtilis filtrate was added, and 15-generation adaptation was not performed).

[0036] The results showed that there was obvious antagonism between the strains (inhibition zone was detected by cross-marking method), and the total viable bacteria count after 72 h of mixed culture was only 52% of that in Example 1 (about 2.1×10 7 CFU / mL); rapeseed fresh weight above ground decreased by 38% compared to Example 1, and wheat thousand-kernel weight decreased by 25%; soil pH decreased by only 0.3 units (compared to 0.8 units in Example 1). Cause Analysis: Co-cultivation and acclimation failed to eliminate interstrain antagonism, and strains were not adapted to each other's metabolites, resulting in a lack of synergistic effects and reduced survival and growth-promoting functions.

[0037] Comparative Example 2: Replacing key inducers in functional synergistic induction Difference from Example 1: In step S2, 0.1 mmol / L phosphoenolpyruvate and 10 μmol / L AC were not added, and an equal amount of distilled water was used instead.

[0038] Predicted results showed that the expression of phosphate-solubilizing genes in Priesteria gigantea and Enterobacterium decreased by 60%, and the combined nitrogen-phosphorus conversion efficiency was only 75% of that in Example 1. The ACC deaminase activity of endophytic glutamicum decreased to 8 U / mg (compared to 20 U / mg in Example 1), and plant root ethylene accumulation increased by 40% compared to Example 1. Rapeseed root length was shortened by 28% compared to Example 1, and the number of wheat tillers decreased by 18%. Cause analysis: The lack of a specific inducer prevented the activation of phosphate-solubilizing genes and ACC deaminase synthesis, resulting in decreased nutrient conversion capacity and stress resistance.

[0039] Comparative Example 3: Omitting the adaptive synchronous reinforcement step: Differences from Example 1: In step S3, saline-alkali gradient acclimation was not performed (15% NaCl culture medium was used directly), and ordinary LB culture medium filtrate (without proline and betaine) was used for metabolite cross-protection.

[0040] Predicted results: The strain's survival rate under 15% NaCl and pH 9.5 conditions was only 22% (compared to 78% in Example 1). Intracellular ATP content decreased by 55% compared to Example 1, and cell membrane integrity was impaired, resulting in a 60% reduction in rhizosphere colonization. In heavily saline-alkali soil (10 g / kg salt content), rapeseed survival was only 45% of that in Example 1, while wheat leaf MDA content (an indicator of oxidative damage) increased by 50%. Analysis of the cause: Without gradient acclimation to enhance salt tolerance and lacking induction with an osmoprotectant, the strain's metabolic activity and stress resistance were significantly reduced in the highly saline-alkali environment.

[0041] Comparative Example 4: Deficiency of Paenibacillus XJ-1: Differences from Example 1: The bacterial complex only contains Priesteria gigantea Y-39, Bacillus endoglutamicum G-30, and Enterobacter C-29, and does not contain Paenibacillus XJ-1. Predicted results: phosphate solubilization (especially organophosphate) capacity decreased by 40% (Paenibacillus XJ-1 is a bifunctional phosphate-solubilizing strain); total ACC deaminase activity decreased by 35%, and expression of plant stress-resistance genes (such as SOD and CAT) decreased by 25%. Rapeseed biomass decreased by 22% during the bolting phase compared to Example 1, and wheat 1000-grain weight decreased by 15% during the grain-filling phase. Cause analysis: Paenibacillus XJ-1's phosphate solubilization and stress resistance functions are irreplaceable; its absence results in incomplete functionality of the complex system and a weakened synergistic effect.

[0042] Comparative Example 5: No bacterial activation was performed during application: Difference from Example 3 (application in rapeseed field): Direct application of inactivated bacterial agent (without shaking culture with saline-alkali soil extract at a ratio of 1:10).

[0043] The results predicted that the number of viable bacteria in the inoculum was only 30% of that in Example 3 (about 6×10 8 CFU / mL), rhizosphere colonization rate decreased by 58%; soil sucrase and urease activities decreased by 30%-40% compared to Example 3; the aboveground wet weight of rapeseed decreased by 32% compared to Example 3, and soil aggregate stability increased by only 8% (compared to 29% in Example 3). Cause Analysis: Failure to increase viable bacterial counts and adaptability through activation resulted in insufficient rhizosphere colonization and metabolic activity, preventing the strain from effectively promoting growth and improving soil quality.

[0044] The following performance tests were performed on Examples 3-4 and Comparative Examples 1-5: Bacterial agent performance indicators: Viable bacteria count: plate count method (TSA medium, cultured at 37°C for 24 h); Survival rate: after culturing for 72 h in a saline-alkaline environment (15% NaCl, pH 9.5), the number of surviving strains / the initial number of strains × 100%; Functional activity: phosphate-solubilizing ability (HPLC to measure soluble phosphorus), IAA production (Salkowski colorimetric method), urease activity (sodium phenolate colorimetric method), siderophore activity (CAS method, As / Ar value).

[0045] Soil improvement indicators: Soil pH: 1:5 soil-water ratio extract, measured with a pH meter; Soil enzyme activities: urease (sodium phenolate colorimetric method), sucrase (3,5-dinitrosalicylic acid method); Aggregate stability: The wet sieving method was used to measure the proportion of aggregates larger than 0.25 mm.

[0046] Crop growth and stress resistance indicators: Biomass: fresh weight (electronic scale), root length / plant height (ruler); Stress resistance indicators: MDA content (thiobarbituric acid method), SOD / CAT activity (nitroblue tetrazolium photoreduction method / UV spectrophotometry); Yield related: wheat thousand-grain weight (electronic scale), rapeseed silique number (counting).

[0047] The results are shown in Table 1-3 below: Table 1 Table 2 Table 3 Note: The “relative value” of crop biomass is based on the control group without fungicide application as 1; Examples 3-4 show the application effects of the optimized composite microbial agent in rapeseed and wheat fields, and Comparative Examples 1-5 are control groups lacking key steps or components. The data reflect the significant advantages of the optimized solution.

[0048] Data Analysis: 1. Analysis of core performance differences of microbial agents: The number of viable bacteria and survival rate: The number of viable bacteria in Examples 3 (rapeseed field) and 4 (wheat field) reached 1.1×10 9 -1.2×10 9 cfu / mL, and the survival rate in 15% NaCl environment was 75%-78%, significantly higher than that of the control example. In the control example 1 (no co-culture acclimation), the number of viable bacteria was only 5.3×10 8 cfu / mL, the survival rate dropped to 52%. Comparative Example 3 (no adaptive enhancement) had a survival rate of only 22% due to lack of saline-alkali gradient acclimation, indicating that it could not survive stably in a high saline-alkali environment. This demonstrates that co-cultivation and acclimation can eliminate antagonism and enhance stress tolerance, which are the foundations for the effective effectiveness of microbial agents.

[0049] Functional activity: Examples 3-4 achieved phosphate solubilization capacities of 40.3-42.6 μg / mL, significantly higher than those of the comparative examples. Comparative Example 2 (inducer replacement) exhibited a phosphate solubilization capacity of 32.1 μg / mL due to the absence of phosphoenolpyruvate and ACC, demonstrating that specific inducers can target and activate functional genes, enhancing nutrient conversion efficiency. Comparative Example 4 (obscured Paenibacillus) exhibited a 30% decrease in phosphate solubilization capacity due to the lack of a bifunctional phosphate-solubilizing strain, confirming the irreplaceable role of Paenibacillus in functional synergy.

[0050] 2. Analysis of soil improvement effect: pH Adjustment and Enzyme Activity: After treatment with Examples 3-4, soil pH dropped to 8.6-8.7, a decrease of 0.7-0.8 units from the initial value (9.4), and urease and sucrase activities were significantly increased. Comparative Example 1 (no co-cultivation and acclimation) saw only a 0.3 unit decrease, due to low bacterial activity and ineffective metabolism of saline and alkali ions. Comparative Example 5 (unactivated inoculant) also saw limited improvement in enzyme activity due to insufficient viable bacterial counts, indicating that activated inoculants can enhance soil microbial metabolism and accelerate saline-alkali amelioration.

[0051] Aggregate stability: Example 3 showed a 42.8% proportion of aggregates larger than 0.25 mm, a 28.9% increase compared to the control. In Comparative Example 3 (no adaptive enhancement), due to low colonization, the proportion of aggregates was only 35.1%. This suggests that the inoculant, through biofilm formation and metabolite secretion, can optimize soil structure and enhance water and fertilizer retention.

[0052] 3. Analysis of crop growth and stress resistance: Biomass and Yield: The relative biomass values ​​of the crops in Examples 3-4 reached 2.1-2.3 (control = 1), with significant increases in the fresh weight of rapeseed and the thousand-grain weight of wheat. Due to functional defects, the relative biomass values ​​of Comparative Examples 1-5 were only 1.1-1.8. In Comparative Example 3 (no adaptive enhancement), the biomass was only 50% of that of the Examples due to low bacterial strain survival. This indicates that the survival and establishment of the inoculant are prerequisites for growth promotion.

[0053] Stress resistance: In Examples 3-4, the MDA content (an indicator of oxidative damage) dropped to 7.9-8.2 μmol / g·FW, while SOD / CAT activity increased by over 50%. In Comparative Example 2 (where the inducer was replaced), the MDA content rose to 10.3 μmol / g·FW due to insufficient ACC deaminase activity, indicating a decrease in stress resistance. This suggests that the microbial agent can enhance antioxidant capacity under saline-alkali stress by regulating plant physiological metabolism.

[0054] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Within the scope of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0055] The present invention is intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A saline-alkali soil plant growth-promoting bacillus, characterized in that: The saline-alkali soil plant growth-promoting Paenibacillus comprises Bacillus and composite bacteria; The composite bacteria are Priesteria gigantea, endophytic glutamicum bacteria and enterobacterium.

2. The saline-alkali soil plant growth-promoting Paenibacillus according to claim 1, characterized in that The preparation process of the saline-alkali soil plant growth-promoting Paenibacillus is as follows: Step S1. Co-culture acclimation; Step S2. Functional synergistic induction; Step S3: Adaptive synchronization reinforcement.

3. The saline-alkali soil plant growth-promoting Paenibacillus according to claim 2, characterized in that The co-culture acclimation process described in step S1 is as follows: Step S101. Single bacteria pretreatment; Step S102: Gradient co-culture acclimation.

4. The saline-alkali soil plant growth-promoting Paenibacillus according to claim 3, characterized in that The process of single bacteria pretreatment in step S101 is as follows: Priesteria gigantea, endophytic glutamicum and Enterobacter were cultured to the logarithmic phase, and the cells were collected by centrifugation, washed twice with sterile saline, and resuspended in a buffer solution containing 5% saline-alkali rhizosphere extract.

5. The saline-alkali soil plant growth-promoting Paenibacillus according to claim 3, characterized in that The gradient co-culture acclimation in step S102 is divided into 1st to 5th generations, 6th to 10th generations and 11th to 15th generations.

6. The saline-alkali soil plant growth-promoting Paenibacillus according to claim 3, characterized in that The process of gradient co-culture acclimation in step S102 is as follows: Step S1021. Passages 1-5: Add 10% sterile filtrate of Bacillus subtilis filtered through a 0.22 μm filter to the basal medium of Priesteria megaterium, endophytic glutamicum, and Enterobacter, and incubate at 30°C and 180 rpm, subculturing once every 24 hours. Step S1022. Generations 6-10: Increase the concentration of the Bacillus subtilis filtrate to 30%, simultaneously reduce the proportion of the single carbon source, and add 0.5% betaine to induce metabolic synergy; Step S1023. Generations 11-15: A mixed culture of Priesteria megaterium, endophytic Bacillus glutamicum, Enterobacter, and Bacillus subtilis was performed in a ratio of 1:1:1:1, using saline-alkali soil leachate with a pH of 9.0 and a salt content of 5 g / kg as the sole culture medium. The dominant coexisting system was screened by plate count to ensure a survival rate of ≥85% for each strain. Step S1024: After acclimation, the strains were tested by the cross-streaking method and showed no inhibition zone on the same plate. The mixed culture was completed by gradient co-culture for 72 hours.

7. The saline-alkali soil plant growth-promoting Paenibacillus according to claim 2, characterized in that The process of functional synergistic induction in step S2 is as follows: Step S201. Adding 0.1 mmol / L of phosphoenolpyruvate to the culture medium of Priesteria megaterium and Enterobacter, and adding 10 μmol / L of 1-aminocyclopropane-1-carboxylic acid to the culture medium of endophytic glutamicum; Step S202. Add 2mmol / LCa to the culture medium 2+ and 0.1% humic acid, synergistic induction was achieved.

8. The saline-alkali soil plant growth-promoting Paenibacillus according to claim 2, characterized in that The process of adaptive synchronization reinforcement in step S3 is as follows: Step S301. Salt-alkali gradient acclimation: Priesteria gigantea, endophytic glutamicum, and Enterobacter are serially passaged in a gradient medium containing 8%-15% NaCl and a pH of 8.5-9.5, increasing the concentration of NaCl by 0.5% or the pH by 0.2 units per generation. Step S302. Metabolite cross-protection: The metabolic fluid of Bacillus subtilis in a high-salt environment containing proline and betaine is collected and used for the cultivation of Priesteria gigantea, endophytic glutamicum and Enterobacter for simultaneous adaptation enhancement.

9. An application of the Paenibacillus sp. for promoting plant growth in saline-alkali soil according to any one of claims 1 to 8, characterized in that: The saline-alkali soil plant growth-promoting Paenibacillus is applied by root irrigation at a dosage of 2 mL / kg soil, and is suitable for rapeseed and wheat.

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