Saline-alkali tolerant rhizosphere growth-promoting strain and application thereof

Abstract

The invention provides a saline-alkaline tolerant rhizosphere growth promoting strain, which is named as Bacillus sp.A015, is preserved in the China Center for Type Culture Collection (CCTCC), has the preservation number of CCTCC NO: M20242724, and is preserved on December 4, 2024; the nucleotide sequence of the 16S rRNA of the growth-promoting rhizosphere strain is as shown in SEQ ID NO. 1. The invention also provides application of the strain, and the strain is used for improving the soil environment of saline-alkali soil and promoting crop growth. The strain has strong functions of fixing nitrogen, dissolving organic phosphorus and inorganic phosphorus, decomposing insoluble potassium and the like, can promote germination and growth of soybeans, lays an important foundation for research of saline-alkali soil bio-fertilizers, biological improvement microbial agents and bacterial fertilizers, and has wide application prospects. The method is of great significance in improvement and utilization of saline-alkali soil, expansion of reserve cultivated land resources in China, guarantee of national grain safety and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of salt-alkali tolerant rhizosphere growth-promoting bacteria, and specifically relates to a salt-alkali tolerant rhizosphere growth-promoting bacteria strain and an application thereof. Background Art

[0002] Saline-alkali land has the characteristics of high soil salt content, low soil fertility, nutrient imbalance, low agricultural productivity and production efficiency, and difficulty in improvement. As the "second genome" of plants and the raw material of saline-alkali land biological improvement agents, rhizosphere microorganisms have great application potential in improving crop resistance to salt-alkali stress and promoting crop growth. Plant Growth Promoting Rhizobacteria (PGPR), as an important component of microbial fertilizers, can colonize in plant roots, not only activating nutrients such as phosphorus and potassium in saline-alkali soil to promote direct absorption and utilization of crops, but also secreting probiotics such as indoleacetic acid (IAA) to promote crop growth and development and increase crop yields. In addition, the composition and content of root secretions are affected by PGPR recruited by the microbial flora, and conversely, the rhizosphere microbial community of plants is affected by root secretions. Therefore, screening rhizosphere growth promoting bacteria of plants in specific habitats is of great significance for improving soil environment and increasing the yield of specific crops. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a salt-alkali tolerant rhizosphere growth-promoting strain in view of the deficiencies of the above-mentioned prior art. The strain has strong functions of nitrogen fixation, dissolution of organic phosphorus and inorganic phosphorus, and potassium dissolution, and can promote soybean growth, laying an important foundation for the research on biological improvement bacteria and bacterial fertilizers for saline-alkali land, and is of great significance for the improvement and utilization of saline-alkali land, the expansion of my country's reserve arable land resources and the guarantee of national food security.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: a salt-alkali tolerant rhizosphere growth-promoting strain, the salt-alkali tolerant rhizosphere growth-promoting strain is named Bacillus sp.A015, preserved in the China Center for Type Culture Collection, the preservation address is Wuhan University, Wuhan, China, the preservation number is CCTCC NO: M20242724, and the preservation date is December 4, 2024; the nucleotide sequence of 16S rRNA of the rhizosphere growth-promoting strain is shown in SEQ ID NO.1.

[0005] The present invention also provides an application of the above-mentioned salt-alkali tolerant rhizosphere growth-promoting strain, wherein the salt-alkali tolerant rhizosphere growth-promoting strain is used to improve the soil environment of saline-alkali land and promote crop growth.

[0006] Preferably, the salt-alkali tolerant rhizosphere growth-promoting strain is used for biological nitrogen fixation, dissolving organic phosphorus and inorganic phosphorus, and decomposing insoluble potassium; the salt-alkali tolerant rhizosphere growth-promoting strain is used for promoting soybean growth.

[0007] Preferably, the salt-alkali tolerant rhizosphere growth-promoting strain is used to improve the germination rate of soybean seeds and increase the length of soybean embryos.

[0008] Compared with the prior art, the present invention has the following advantages:

[0009] The strain Bacillus sp.A015 of the invention has the functions of strong nitrogen fixation, dissolving organic phosphorus and inorganic phosphorus, decomposing insoluble potassium, etc., and can promote soybean growth, thus laying an important foundation for the research of biological improvement bacteria agent and bacterial fertilizer for saline-alkali land, and having great significance for carrying out the improvement and utilization of saline-alkali land, expanding my country's reserve arable land resources, and ensuring national food security, etc.

[0010] The present invention is further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is the determination of the nitrogen fixation function of strain A015 in Example 1 of the present invention.

[0012] Figure 2 This is the determination of the potassium solubilizing ability of the A015 strain in Example 1 of the present invention.

[0013] Figure 3 This is the determination of the phosphorus dissolving capacity of the A015 strain in Example 1 of the present invention.

[0014] Figure 4 This is the determination of the ability of the A015 strain to dissolve organic phosphorus in Example 1 of the present invention.

[0015] Figure 5 This is the result of the salt tolerance experiment of strain A015 in Example 1 of the present invention.

[0016] Figure 6 This is the result of the alkali resistance experiment of strain A015 in Example 1 of the present invention.

[0017] Figure 7 This is the colony morphology of the A015 strain in Example 1 of the present invention on the improved LB medium.

[0018] Figure 8 It is the growth curve measurement result of strain A015 in Example 1 of the present invention.

[0019] Fig. 9 This is the Gram staining result of strain A015 in Example 1 of the present invention under an optical microscope.

[0020] Fig.10 It is a phylogenetic tree diagram of the A015 strain in Example 1 of the present invention based on 16S rRNA phylogeny.

[0021] Fig.11 This is a test diagram of the soybean seed germination rate using strain A015 in Example 1 of the present invention. DETAILED DESCRIPTION

[0022] Example 1

[0023] The test culture medium formulas in this embodiment are as follows:

[0024] Improved LB medium (isolation and purification, salt-alkali tolerance experiment): tryptone 10.0 g / L, yeast extract 5.0 g / L, NaCl 50.0 g / L (5%), agar 18 g / L, pH 7.0-7.2.

[0025] LB liquid medium: tryptone 10.0 g / L, yeast extract 5.0 g / L, NaCl 10.0 g / L, pH 7.0-7.2.

[0026] Ashby nitrogen-free medium (for determination of nitrogen fixation function): mannitol 10.0 g / L, KH2PO4 0.2 g / L, MgSO4·7H2O 0.2 g / L, NaCl 0.2 g / L, CaCO3 5.0 g / L, CaSO4 0.1 g / L, pH 6.8-7.0.

[0027] Montgina organophosphorus medium (used for verification of solubilized organophosphorus function): MnSO4·H2O 0.03 g / L, FeSO4·7H2O 0.03 g / L, CaCO3 5.0 g / L, glucose 10.0 g / L, (NH4)2SO4 0.5 g / L, lecithin 0.2 g / L, NaCl 0.3 g / L, KCl 0.3 g / L, yeast extract 0.4 g / L, agar 18 g / L, pH 7.0-7.2.

[0028] Inorganic phosphorus culture medium: glucose 10g / L, MgCl2·6H2O 5g / L, MgSO4·7H2O 0.25g / L, KCL0.2g / L, (NH4)2SO40.1 g / L, Ca3(PO4)25g / L, pH 6.8-7.0.

[0029] Potassium-dissolving culture medium: sucrose 10.0 g / L, yeast extract 0.5 g / L, (NH4)2SO4 1.0 g / L, Na2HPO4 2.0 g / L, MgSO4·7H2O 0.5 g / L, CaCO3 1.0 g / L, potassium feldspar 1.0 g / L, agar 18 g / L, pH 7.0-7.2.

[0030] (I) Isolation and purification of strains

[0031] Soil samples: Soil samples of cotton root system from saline-alkali land in Tailan River Irrigation Area, Wensu County, Aksu Prefecture, Xinjiang (80°21′44″-81°10′14″E, 40°41′41″-42°15′13″N).

[0032] The soil suspension was prepared using saline-alkali soil samples from the Tailan River irrigation area in Wensu County, Aksu Prefecture, Xinjiang, and then diluted to a concentration of 10 -4 , spread on modified LB medium for culture, pick single colonies, repeatedly streak and isolate until purified, and obtain strain A015.

[0033] The specific separation and purification method is as follows: weigh 10 g of soil sample into a conical flask filled with 90 mL of sterile water, shake at 200 r / min for 20 min, take the soil suspension and perform -1 , 10 -2 , 10 -3 , 10 -4 , 10 -5 Gradient dilution, select the appropriate dilution gradient (10 -4 ) is evenly spread on a modified LB medium plate and cultured in a 30°C incubator for 2-3 days. When a single colony grows, it is purified multiple times on the plate by streaking to obtain a pure culture. The strain is inoculated into a slant medium and cultured at a constant temperature of 30°C for 4-5 days. It is then stored in a 4°C refrigerator for later use.

[0034] (II) The isolated strains were inoculated into different functional culture media

[0035] The different strains (J-100-3, A-0-4, A-0-5, A-0-8, A-0-15, J-200-6) obtained by separation were inoculated on different functional culture media. The specific determination methods are as follows (1)-(4), and a strain A015 with the functions of nitrogen fixation, dissolution of organic and inorganic phosphorus, and potassium solubilization was screened out. The organic phosphorus solubilization index of strain A015 was 0.5, and the quantitative experimental results showed that its conversion of lecithin reached 3.77 mg / L; the inorganic phosphorus solubilization index was 1.3, and the quantitative experimental results showed that its conversion of calcium phosphate reached 24.79 mg / L; the potassium solubilization index was 0.9, and the conversion of potassium feldspar powder reached 5.16 mg / L. The specific results are shown in Table 1. Figures 1 to 4 shown.

[0036] Table 1 Functional assay results of different strains

[0037] Strain number Separation source Nitrogen fixation capacity Solution of inorganic phosphorus Organic phosphorus solution Potassium-releasing function J-100-3 Jinghe County - - - D / d=1.1 A-0-4 Ebby Lake - - D / d=0.7 - A-0-5 Ebby Lake + - - D / d=0.8 A-0-8 Ebby Lake - - - D / d=0.7 A015 Tailan River ++ D / d=1.3 D / d=0.5 D / d=0.9 J-200-6 Jinghe County - - - -

[0038] Note: "+" means the strain has the corresponding function, the more the number, the stronger the ability; "-" means it does not have the corresponding function. "D" represents the diameter of the transparent circle, and "d" represents the growth diameter of the strain. The larger the D / d ratio, the stronger the corresponding function.

[0039] (1) Determination of nitrogen fixation function:

[0040] Ashby nitrogen-free medium was used to determine the nitrogen fixation ability of bacterial isolates. The purified strains were inoculated on Ashby nitrogen-free medium and cultured at 28°C for 7 days. Whether the bacteria could grow normally on the Ashby nitrogen-free medium was used to determine whether the bacteria had the ability to fix nitrogen, and the size of the nitrogen fixation ability was determined based on the diameter of the colony growth.

[0041] The results of the nitrogen fixation experiment are as follows Figure 1 As shown, strain A015 grew well on Ashby nitrogen-free medium after constant temperature culture, indicating that strain A015 has nitrogen fixation function.

[0042] (2) Determination of the ability to decompose insoluble potassium:

[0043] Qualitative experiment: The purified strain was inoculated on the potassium-dissolving medium, cultured in a constant temperature incubator at 28°C for 5-7 days, and its transparent zone diameter (D) and colony diameter (d) were measured. The potassium-dissolving transparent zone is formed when the strain secretes organic acids and other minerals to dissolve the insoluble potassium minerals in the medium when growing on the medium. Therefore, the size of the potassium-dissolving transparent zone diameter reflects the strain's ability to release potassium ions. The larger the ratio of the potassium-dissolving zone transparent diameter (D) to the colony diameter (d) of potassium-dissolving and degrading bacteria, the higher the potassium-dissolving activity of the strain per unit growth area, and the better the potassium-dissolving effect of the strain.

[0044] Quantitative experiment: Inoculate the prepared bacterial suspension at a 1% (v / v) inoculation volume into 50 mL of potassium-dissolving liquid culture medium without agar, culture at 30°C, 180 r / min for 3 days, centrifuge at 6000 r / min for 20 min, take the supernatant, and determine the potassium content in the supernatant using a flame spectrophotometer.

[0045] like Figure 2 As shown in the figure, the qualitative experimental results showed that the potassium-solubilizing index of strain A015 was 0.9, and the quantitative test results showed that the conversion amount of potassium feldspar powder by strain A015 reached 5.16 mg / L after 3 days of cultivation.

[0046] (3) Dissolution of organic phosphorus experiment:

[0047] Qualitative determination method for organic phosphorus decomposition: Inoculate the purified strain on the Montana organic phosphorus medium, culture it in a constant temperature incubator at 28°C for 5-7 days, and measure its phosphorus dissolution circle diameter (D) and colony diameter (d). Since the strain with phosphorus dissolution function can convert the lecithin in the culture medium into substances such as choline and glycerol during the culture process, and choline will be further decomposed into amines, organic acids, carbon dioxide, etc., and finally form a transparent circle. Therefore, the larger the ratio of the phosphorus dissolution circle diameter (D) of the organic phosphorus degrading bacteria to the colony diameter (d), the better the organic phosphorus degradation effect.

[0048] Quantitative experiment of dissolved organic phosphorus: The bacterial suspension was inoculated at a 1% (v / v) inoculation rate into 50 mL of organic phosphorus liquid culture medium at 30°C and 180 r / min for 3 days. The supernatant was collected after centrifugation at 10,000 r / min for 15 min, and the effective phosphorus content in the supernatant was determined by molybdenum blue colorimetry.

[0049] like Figure 3 As shown, the qualitative experimental results showed that the organic phosphorus decomposition index of strain A015 was 0.5; according to the quantitative experimental results, the conversion amount of phosphatidylcholine was 3.77 mg / L after 3 days of cultivation.

[0050] (4) Dissolution of inorganic phosphorus experiment:

[0051] Qualitative determination method for inorganic phosphorus dissolution: Inoculate the purified strain on inorganic phosphorus culture medium, culture in a constant temperature incubator at 28℃ for 5-7 days, and measure its phosphorus dissolution circle diameter (D) and colony diameter (d). Since phosphorus dissolution bacteria can convert Ca3(PO4)2 in the culture medium from an insoluble state to a soluble state through secretion acidification, chelation and other pathways, the phosphate in the culture medium can be released and diffused, thus forming a transparent circle. Therefore, the larger the ratio of the phosphorus dissolution circle diameter (D) to the colony diameter (d) of inorganic phosphorus degrading bacteria, the better the inorganic phosphorus degradation effect.

[0052] Quantitative experiment of dissolved inorganic phosphorus: The bacterial suspension was inoculated at a 1% (v / v) inoculation rate into 50 mL of inorganic phosphorus liquid culture medium at 30°C and 180 r / min for 3 days. The supernatant was collected after centrifugation at 10,000 r / min for 15 min, and the effective phosphorus content in the supernatant was determined by molybdenum blue colorimetry.

[0053] like Figure 4 As shown, the qualitative experimental results showed that the inorganic phosphorus decomposition index of strain A015 was 1.3; the quantitative experimental results showed that the amount of calcium phosphate converted by A015 was 24.79 mg / L after 3 days of cultivation.

[0054] (III) Salt and alkali resistance test:

[0055] 1. Preparation of Bacterial Suspension

[0056] Under sterile operation, pick a single colony after purification and inoculate it into a 250mL conical flask containing 100mL liquid LB medium. Incubate at 180r / min, 30°C, shake and culture for 2 days until the late logarithmic growth phase. Centrifuge at 8000r / min for 10min, pour off the supernatant to collect the bacteria, and adjust the OD with sterile water. 600 = about 0.5 for standby use.

[0057] 2. Salt tolerance test

[0058] LB liquid culture medium with pH=7.0 and NaCl content of 0%, 3%, 5%, 10%, 15%, and 20% was prepared respectively. The prepared bacterial suspension was inoculated into LB liquid culture medium with different NaCl concentration gradients at an inoculum volume of 1%. The shaking conditions were set at 30°C and 180r / min. The OD was measured after 7 days. 600 The salt tolerance of the strain was determined.

[0059] 3. Determination of alkali resistance

[0060] Based on the results of the salt tolerance test, the alkali tolerance of the strain was further determined. The bacterial suspension was inoculated at a 1% inoculum into LB liquid culture medium with a NaCl concentration of 5% and different pH gradients (pH = 3, 5, 6, 8, 10, 11, 12, 13). The shaking conditions were set at 30°C and 180r / min. After 7 days, the OD 600 The acid-base tolerance of the strain was determined.

[0061] The salt-alkali resistance experiment showed that strain A015 could tolerate an alkaline environment of 20% (w / v) NaCl concentration and pH = 10, and grew best in a medium containing 5% (w / v) NaCl and pH 8. Figure 5 , Figure 6 shown.

[0062] (IV) Morphological and physiological and biochemical identification of strains

[0063] Morphological identification method: When the strains on the culture medium are clearly visible and growing well, refer to the Bergey's Bacterial Identification Manual to observe the morphological characteristics of the strains on the culture medium, such as colony color, shape, transparency, etc. Take a small amount of the strains and streak them on the modified LB medium, and pick the purified single colonies for Gram staining.

[0064] Determination of growth curve: A single colony of A015 was picked and placed in a 500 mL conical flask containing 350 mL LB liquid medium. After culturing in a shaker at 30°C and 180 r / min for 2 days, the bacteria were centrifuged at 10000 r / min and 4°C for 10 min. The collected bacteria were made into OD 600= 0.5 bacterial suspension, and then transferred to 350mL LB liquid medium at a 5% inoculation volume. The sampling time was 0, 12, 24, 36, 48, 72, 96, and 120 hours, and the absorbance value at 600nm on the UV spectrophotometer was used to reflect the cell concentration. Figure 8 shown.

[0065] Catalase test: Use a sterilized inoculation loop to pick up an appropriate amount of activated bacteria and smear them on a glass slide. Add 2-3 drops of 3% hydrogen peroxide solution to perform a catalase test and observe whether bubbles are generated. If bubbles are generated, it proves that the catalase reaction is positive, otherwise it is negative.

[0066] The above experimental results show that the colony morphology of the target strain A015 in the improved LB solid medium is as follows Figure 7 As shown, the strain is light yellow, opaque, with nearly rounded edges, flat, and a rough and wrinkled surface. Figure 8 The growth curve shows that strain A015 reaches the late logarithmic growth stage at about 48 hours of growth. Fig. 9 As shown in the figure, the Gram staining result is red, indicating a Gram-negative strain. The catalase reaction result is positive.

[0067] (V) Molecular identification of strains

[0068] Molecular identification method: Pick a single colony with a sterile inoculation loop, add 200 μL of 5% (w / v) BT-chelex100 resin (prepared with distilled water, sterilized at 121°C for 30 min), boil in a boiling water bath for 15 min, quickly freeze at -20°C, thaw at room temperature, and spin at 4°C, 6000 r / min. -1 Centrifuge for 3 minutes, and take 2 μL of the supernatant as template DNA. The template DNA was amplified using the universal primers 27F (5'-AGAGTTTGATCCTGGCTCAG-3) and 1492R (5'-GGTTACCTTGTTACGACT T-3') of the bacterial 16S rRNA gene.

[0069] The total volume of the PCR reaction was 25 μL, including 2.0 μL DNA template, 0.5 μL upstream and downstream primers, 9.5 μL ddH2O, and 12.5 μL Green tapMix enzyme. The PCR reaction program was: 95°C, 5 min pre-denaturation; 94°C, 1 min denaturation, 55°C, 1 min annealing, 72°C, 1.5 min extension, 35 cycles; 72°C, 10 min extension, and 4°C storage. After 1.0% agarose gel electrophoresis, the PCR product was sent to Shanghai Sangon Biotechnology Co., Ltd. for sequencing. The sequencing results were compared and analyzed on the bacterial and archaeal 16SrRNA gene database EZBioCloud (https: / / www.ezbiocloud.net / ), and the phylogenetic evolutionary tree was constructed using Mega11.0 software.

[0070] The 16S rRNA gene fragment of strain A015 obtained by sequencing was 1440 bp. Homology comparison analysis of the 16S rRNA sequence of the strain A015 in the EZBioCloud database (https: / / www.ezbiocloud.net / ) showed that the strain belonged to the genus Bacillus and was similar to Bacillus zhangzhouensis DW5-4. T (JOTP01000061) showed a similarity of 99.17%. Based on the homology comparison results, MEGA 11.0 was used to construct a phylogenetic tree. The results are as follows Fig.10 shown.

[0071] (VI) Growth promotion test of strains

[0072] Preparation of bacterial suspension: After the test strain is activated, it is inoculated into a 250 mL conical flask containing 150 mL LB liquid medium, and cultured at 30 ° C and 180 r / min for 72 h; centrifuged at 8000 r / min for 10 min, the supernatant is discarded, the bacteria are collected, washed with sterile water twice, and resuspended in sterile water, and the OD of the bacterial suspension is adjusted. 600 =0.5, for standby use.

[0073] Seed germination test: Select Heinong 87 soybean seeds with full grains and the same size, and carry out surface disinfection (soak in 70% alcohol for 10 minutes, rinse with sterile water 3 times). The experiment has two treatments: CK (blank control group) and A015 (inoculated with A015 bacterial suspension), with 3 replicates for each treatment and 20 seeds for each replicate. Place 2 layers of sterilized filter paper in each sterile culture dish, and spread the sterilized and air-dried soybean seeds on the filter paper. Add 5 mL of sterile water to each culture dish of the CK (control group), and add 5 mL of the prepared bacterial suspension to each culture dish of the A015 treatment group. Culture at 28°C in the dark for 3 days. During the culture process, add an appropriate amount of sterile water to keep the filter paper moist, and then calculate the germination rate and sprout length of the seeds. The specific results are shown in Table 2. Fig.11 shown.

[0074] Table 2 Effects of different treatments on soybean seed germination

[0075] deal with Germination rate (%) Germ length (cm) CK 70.0％ 1.60±0.36 A015 95.0％ 2.93±0.40

[0076] The results of the seed germination test showed that compared with CK, the germination rate of seeds inoculated with A015 increased by 26.3%, and the embryo length increased by 45.4%, with a significant growth-promoting effect.

[0077] The salt-alkali tolerant rhizosphere growth-promoting strain A015 screened by the present invention was named Bacillus sp.A015, and was deposited in the China Center for Type Culture Collection, with the deposit address being Wuhan University, Wuhan, China, with the deposit number being CCTCC NO: M20242724, and the deposit date being December 4, 2024; the nucleotide sequence of its 16S rRNA is shown in SEQ ID NO.1.

[0078] The salt-alkali tolerant rhizosphere growth-promoting strain A015 of the present invention can be used for nitrogen fixation, dissolving organic phosphorus and inorganic phosphorus, and decomposing insoluble potassium. These functions play an important role in increasing the yield and quality of crops in saline-alkali land, reducing the use of chemical fertilizers, improving the soil environment, and the sustainable utilization and development of agricultural soil.

[0079] The strain A015 of the present invention has strong functions of nitrogen fixation, phosphorus dissolution, decomposition of insoluble potassium, and promotion of seed germination. The dissolution amount of lecithin is 3.77 mg / L, the dissolution amount of insoluble calcium phosphate reaches 24.79 mg / L, and the conversion amount of potassium feldspar powder reaches 5.16 mg / L. It can grow normally in a saline-alkali environment of 5% NaCl and pH=8, and the germination rate of soybean seeds is increased by 26.3%. The multiple growth-promoting functions of the strain can help plants decompose and utilize insoluble silicate inorganic minerals such as insoluble phosphorus and potassium feldspar in the soil, convert them into soluble nutrients, increase the content of effective nutrients in the soil, improve the utilization rate of chemical fertilizers, and are conducive to cultivating and exerting soil ecological fertility and maintaining agricultural ecological balance. The excavation of strain resources with salt-alkali tolerance and excellent growth-promoting functions lays an important foundation for the research of biological improvement bacteria and bacterial fertilizers for saline-alkali land, and is of great significance for carrying out saline-alkali land improvement and utilization, expanding my country's reserve arable land resources, and ensuring national food security.

[0080] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A salt-alkali tolerant rhizosphere growth-promoting strain, characterized in that: The salt- and alkali-tolerant rhizosphere growth-promoting strain is named Bacillus sp. A015, deposited in the China Center for Type Culture Collection, with a deposit number of CCTCC NO: M20242724 and a deposit date of December 4, 2024; the nucleotide sequence of 16S rRNA of the rhizosphere growth-promoting strain is shown in SEQ ID NO.

1.

2. An application of the salt-alkali tolerant rhizosphere growth-promoting strain as claimed in claim 1, characterized in that: The salt-alkali tolerant rhizosphere growth-promoting strain is used for improving the soil environment of saline-alkali land and promoting crop growth.

3. The use according to claim 2, characterized in that: The salt-alkali tolerant rhizosphere growth-promoting strain is used for biological nitrogen fixation, dissolving organic phosphorus and inorganic phosphorus, and decomposing insoluble potassium; the salt-alkali tolerant rhizosphere growth-promoting strain is used for promoting soybean growth.

4. The use according to claim 3, wherein the salt-alkali tolerant rhizosphere growth-promoting strain is used to improve the germination rate of soybean seeds and increase the length of soybean embryos.

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