Synthetic microbial consortium for enhancing drought resistance of soybean and application thereof

Abstract

This invention discloses a synthetic microbial community for enhancing the drought resistance of cultivated soybeans and its application, belonging to the field of microbial technology. The synthetic microbial community disclosed in this invention is composed of equal parts of various immobilized microencapsulated bacterial agents. The synthetic microbial community disclosed in this invention can improve the drought resistance of cultivated soybeans and increase soybean biomass.

Description

Technical Field

[0001] This invention relates to the field of microbial technology, and more specifically to a synthetic microbial community that enhances the drought resistance of cultivated soybeans and its application. Background Technology

[0002] Drought stress is a major abiotic stress factor constraining global soybean production, severely impacting soybean growth, development, and final yield, and posing a persistent threat to agricultural sustainability and food security. Against this backdrop, exploring and utilizing plant microbiome resources has become a cutting-edge direction and key strategy for enhancing crop climate resilience.

[0003] Wild soybean, as a close wild relative of cultivated soybean, has developed remarkable drought resistance and environmental adaptability through long-term natural selection. Its unique rhizosphere and endophytic microbiome is considered a crucial biological component synergistically mediating this stress resistance, containing a wealth of beneficial microbial resources that have yet to be systematically explored and efficiently utilized. However, how to systematically analyze this specific microbial resource pool and, based on rational design, transform its dominant strains into stable, efficient, and field-suitable microbial preparations remains a current technological bottleneck in this field. Existing microbial inoculants generally suffer from outdated formulation processes, low cell survival rates, insufficient field colonization capacity, and unstable functional expression, resulting in their growth-promoting and stress-resistance effects failing to meet expectations in practical applications. Therefore, addressing the aforementioned technological gaps and industry needs, there is a need for a synthetic microbial community derived from wild soybean microbial resources that can effectively enhance the drought resistance of cultivated soybeans, along with its highly efficient preparation.

[0004] Therefore, providing a synthetic microbial community that enhances the drought resistance of cultivated soybeans and its application is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a synthetic microbial community for enhancing the drought resistance of cultivated soybeans and its application.

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

[0007] A synthetic microbial community for enhancing the drought resistance of cultivated soybeans, wherein the synthetic microbial community is composed of equal parts of immobilized microcapsule agents of Crossiella equiJCM12685, Pseudaminobacter granuli LMG 29567, Devosia sp. JCM 28289, Agromyces sp. JCM 28256, Bacillus mojavensis ATCC 51516, Streptomyces sp. ATCC 39343, Streptomyces sp. ATCC 25607, and Microbacterium yannicii LMG 25521; or is composed of Crossiella equiJCM 12685, Pseudaminobacter granuli LMG 29567, Devosia sp. JCM 28289, Agromyces sp. JCM 28256, and Bacillus arachidis GDMCC. An immobilized microcapsule bacterial agent consisting of 812564, Streptomyces tauricus ATCC 27470, Priestia megaterium DSM 110117, and Paenibacillus sp. DSM 110293 was prepared by mixing equal amounts of the microcapsule bacterial agent. The effective viable counts of the immobilized microcapsule bacterial agents containing *Crossiella equi* JCM 12685, *Pseudaminobacter granuli* LMG 29567, *Devosia* sp. JCM 28289, *Bacillus mojavensis* ATCC 51516, *Agromyces* sp. JCM 28256, *Streptomyces* sp. ATCC 39343, *Streptomyces* sp. ATCC 25607, *Microbacterium yannicii* LMG 25521, *Bacillus arachidis* GDMCC 812564, *Streptomyces tauricus* ATCC27470, *Priestia megaterium* DSM 110117, and *Paenibacillus* sp. DSM 110293 were 2.45 × 10⁻⁶. 9 2×10 8 8.5×10 8 8.5×10 8 1.5×10 81.55×10 9 1×10 8 7.5×10 8 1×10 9 2×10 8 2.1×10 9 2.5×10 8 CFU / g.

[0008] Furthermore, the preparation method of the immobilized encapsulated bacterial agent is as follows: The viable bacterial count reaches 1×10⁻⁶. 8 The bacterial culture was concentrated 14 times to obtain a concentrated culture medium of the strain. The concentrated culture medium of the strain, 3% sodium alginate solution, and skim milk were mixed in equal volumes to prepare an immobilization and embedding system. The immobilization and embedding system was added dropwise to a 0.15 mol / L sterile CaCl2 solution and sterilized at 4°C for 18 h. After washing three times with 0.85% sterile saline, the immobilized and embedded microcapsule bacterial agent was obtained.

[0009] Furthermore, the application of the synthetic microbial community in improving the drought resistance of cultivated soybeans.

[0010] Furthermore, the application of the synthetic microbial community in increasing soybean biomass.

[0011] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a synthetic microbial community and its application for enhancing the drought resistance of cultivated soybeans. The synthetic microbial community can improve the drought resistance of cultivated soybeans and increase soybean biomass. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0013] Figure 1Preparation of microcapsule agents for immobilizing various strains of synthetic bacteria. Synthetic bacterial group 1 is on the left, and synthetic bacterial group 2 is on the right. The first row on the left contains *Crossiella equi* JCM 12685, *Pseudaminobacter granuli* LMG 29567, and *Devosia* sp. JCM 28289; the second row contains *Agromyces* sp. JCM 28256, *Bacillus mojavensis* ATCC 51516, and *Streptomyces* sp. ATCC 39343; the third row contains *Streptomycess* sp. ATCC 25607 and *Microbacterium yannicii* LMG 25521. The first row on the right contains Crossiellaequi JCM 12685, Pseudaminobacter granuli LMG 29567, and Devosia sp. JCM 28289; the second row contains Agromyces sp. JCM 28256, Bacillus arachidis GDMCC 812564, and Streptomycestauricus ATCC 27470; the third row contains Priestia megaterium DSM 110117 and Paenibacillus sp. DSM 110293.

[0014] Figure 2 The images show the phenotypes of soybean plants in mushroom bags. The three bags on the left represent the watering treatment (W), and the three bags on the right represent the drought treatment (D). From left to right, the three bags represent CK, inoculation with SynCom1 (S1), and SynCom2 (S2), respectively.

[0015] Figure 3 The images show the phenological characteristics of soybean plants removed from mushroom bags for potted experiments, after the roots were washed and dried with absorbent paper. The left side shows the watering treatment (W), and the right side shows the drought treatment (D). The ruler is 50cm.

[0016] Figure 4 The SPAD value (a) and phenotypic index (bg) of the experimental soybean were used for re-inoculation. The statistical results were subjected to Tukey HSD test. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Culture medium formulation: R2A medium: tryptone 0.25 g / L, acid-hydrolyzed casein 0.5 g / L, yeast extract 0.5 g / L, soluble starch 0.5 g / L, dipotassium hydrogen phosphate 0.3 g / L, magnesium sulfate 0.1 g / L, sodium pyruvate 0.3 g / L, peptone 0.25 g / L, glucose 0.5 g / L, pH 7.2 ± 0.2.

[0019] Nitrogen-fixing medium: potassium dihydrogen phosphate 0.2 g / L, magnesium sulfate 0.2 g / L, sodium chloride 0.2 g / L, calcium carbonate 5.0 g / L, mannitol 10.0 g / L, calcium sulfate 0.1 g / L, pH 7.0 ± 0.1.

[0020] Inorganic phosphorus culture medium: glucose 10g / L, ammonium sulfate 0.5g / L, yeast extract 0.5g / L, sodium chloride 0.3g / L, potassium chloride 0.3g / L, magnesium sulfate 0.3g / L, ferrous sulfate 0.03g / L, manganese sulfate 0.03g / L, tricalcium phosphate 5g / L, pH 7.0-7.5.

[0021] Organophosphorus culture medium: glucose 10 g / L, ammonium sulfate 0.5 g / L, yeast extract 0.5 g / L, sodium chloride 0.3 g / L, potassium chloride 0.3 g / L, magnesium sulfate 0.3 g / L, ferrous sulfate 0.03 g / L, manganese sulfate 0.03 g / L, lecithin 0.2 g / L, calcium carbonate 1 g / L, pH 7.0-7.5.

[0022] Add 18 g / L of agar to the solid culture medium.

[0023] Example 1: Isolation of strains and identification of species classification information Soil samples were collected for extensive microbial analysis. These samples came from soybean rhizosphere soil obtained in field experiments and from wild soybean rhizosphere soil subjected to mild and moderate drought treatments in pot experiments. The field experiments were conducted in twelve districts and counties of Shaanxi Province, including Ansai District, Wuqi County, and Luochuan County in northern Shaanxi; Longxian County, Chengcheng County, Dali County, Yaozhou District, and Yijun County in Guanzhong Plain; and Lueyang County, Hantai District, Zhenping County, and Xunyang City in southern Shaanxi. Representative soybean-maize intercropping fields were selected, marked, and six 10 m × 10 m quadrats were randomly selected. Soil samples were collected during the soybean seeding and pod-filling stages.

[0024] Soil for the pot experiment was collected from the Caoxinzhuang Experimental Farm of Northwest A&F University. After passing through a 2 mm sieve, the soil was placed in flowerpots, with approximately 1.5 kg of soil in each pot. Each treatment was replicated 6 times, for a total of 108 pots. Three different varieties of wild soybean (Xi'an, Shaanxi; Xianyang, Shaanxi; Jinan, Shandong) and three different varieties of cultivated soybean (Zhonghuang 13, Jidou 12, and Jindou 21) were selected as experimental plant materials. After the soybeans sprouted, 1-2 plants with significantly different growth rates were removed. Watering was carried out daily during the growing season. For the control group (CK, soil relative humidity 65%-75%), sufficient water supply was maintained throughout the entire growth stage of the plants. For mild drought (L, soil relative humidity 50%-60%) and moderate drought (M, soil relative humidity 40%-50%), drought stress was introduced after the soybeans developed their first true leaves. Soil moisture was measured regularly using a soil moisture meter, and water was replenished to the corresponding drought gradient daily. Rhizosphere soil samples were collected from wild and cultivated soybeans during their branching and flowering stages for soil DNA extraction.

[0025] Rhizosphere soil samples collected from pot experiments of field soybeans and wild soybeans under mild and moderate drought treatments were uniformly mixed to prepare two soil samples. 1 g of soil sample was weighed from each sample and placed in a sterile 10 mL centrifuge tube. 9 mL of sterile water was added in a laminar flow hood to obtain 10... -1 Soil suspension at a specific concentration. Place the centrifuge tube on a shaker and shake for 30 minutes to mix thoroughly. Then, transfer 1 mL of the soil suspension into a centrifuge tube containing 9 mL of sterile water, and record this as 10 mL. -2 Repeat the above steps to obtain a dilution factor of 10. -6 10 -7 and 10 -8 Soil suspensions were prepared. 20 μL of each of the above-mentioned dilutions of soil suspension were transferred to R2A and LB solid media, and spread evenly using a sterile spreader. Three replicates were set for each dilution gradient. All plates were sealed with film and incubated at 28°C for 3 days. Colony growth morphology was observed daily. Colonies of different sizes and morphologies were then streaked to new R2A or LB media. Each strain was purified 2–3 times. For strain identification, purified single colonies were picked up with a pipette, dissolved in 10 μL of sterile water, and mixed thoroughly. 1 μL was used as a template for PCR amplification using primers 27F / 1492R. After amplification, the PCR product was sequenced in 16S, and the species information of the strain was determined by BLAST alignment.

[0026] A total of 147 bacterial strains were isolated from the soil of soybean-maize intercropping fields, including 44 strains of Actinobacteria, 73 strains of Bacillus, 5 strains of Bacteroidetes, and 25 strains of Pseudomonas, belonging to 9 classes, 16 orders, 26 families, and 38 genera. In pot experiments, 239 bacterial strains were isolated from mildly and moderately arid soils of wild soybean, including 116 strains of Actinobacteria, 58 strains of Bacillus, 6 strains of Bacteroidetes, and 59 strains of Pseudomonas, belonging to 8 classes and 64 genera.

[0027] Example 2 Screening of drought-resistant and growth-promoting bacteria Screening of drought-resistant bacteria. For screening drought-resistant strains, 20% PEG-6000 was used as the drought condition, with no PEG-6000 added as a control. Each treatment was performed in triplicate. Candidate bacteria were picked and added to 20 mL of LB liquid medium and cultured on a shaker at 28℃ and 180 rpm for 3 days. OD was then adjusted. 600 After reaching approximately 0.6, 1% of the culture medium was inoculated into 20 mL of LB liquid medium with and without PEG-6000, respectively, and cultured on a shaker for 3 days under the same conditions. OD was then measured. 600 Bacteria with a decrease in absorbance value of less than 30% are considered drought-resistant bacteria.

[0028] Screening of growth-promoting bacteria. Candidate bacteria were picked and added to 20 mL of LB liquid medium. After culturing for 3 days at 28°C and 180 r / min on a shaker, the OD was adjusted. 600 Adjust the concentration to approximately 0.6. After shaking to mix thoroughly, add 2.5 μL of the bacterial suspension to nitrogen-fixing, organic phosphorus, and inorganic phosphorus solid culture media, adding the suspension three times per plate. After the bacterial suspension has completely dried, incubate upside down in a 28°C incubator for 3 days, observing whether the strain has a clear zone. Strains with clear zones are considered growth-promoting strains; the larger the clear zone, the stronger the growth-promoting properties of the strain.

[0029] Drought resistance screening was conducted on strains isolated from wild soybean under mild and moderate drought conditions in pot experiments, resulting in 33 drought-resistant bacteria, including 5 strains with nitrogen-fixing capabilities, 7 strains capable of solubilizing organic phosphorus, and 25 strains capable of solubilizing inorganic phosphorus. Field experiments yielded 9 strains with nitrogen-fixing capabilities, 13 strains capable of solubilizing organic phosphorus, and 26 strains capable of solubilizing inorganic phosphorus.

[0030] Example 3 Construction of Synthetic Microbial Community Using the drought resistance of the strains as a fundamental condition, core microorganisms were screened based on Zi-Pi analysis, network node degree, and proximity centrality. Core bacteria were obtained by comparing them with isolated strains, and three key species from wild soybean were isolated, belonging to the genera *Crossiella*, *Pseudaminobacter*, and *Devosia*, respectively. *Crossiella* and *Devosia* showed relatively strong drought resistance. Following the principle of functional complementarity and synergy, and based on the drought-resistant and growth-promoting characteristics of the strains, two synthetic microbial communities, SynCom1 (S1) and SynCom2 (S2), were finally constructed. Antagonism tests were performed on eight strains from each of the two synthetic microbial communities, revealing no antagonistic interactions between them; therefore, they can be used for constructing synthetic microbial communities.

[0031] Table 1 Construction of synthetic microbial communities

[0032] Example 4 Preparation of microencapsulated bacterial agent 1) Preparation of microencapsulated bacterial agents The microencapsulated bacterial agent was prepared using a 3% sodium alginate solution, a 4.5 gauge (0.45 × 15 mm) syringe needle, a 0.15 mol / L CaCl2 solution, and 10 mL of skim milk. The preparation steps for the microencapsulated bacterial agent are as follows: (1) The candidate strain was inoculated into an Erlenmeyer flask containing 150 mL of LB liquid medium and cultured on a shaker at 28℃ and 180 r / min until the viable count reached 1×10⁻⁶. 8 The bacterial culture was prepared by dispersing CFU / mL.

[0033] (2) Take about 70 mL of bacterial culture into 100 mL round-bottom centrifuge tubes, balance them, centrifuge at 6000 r / min for 5 min, remove the supernatant, add fresh LB liquid medium and mix by pipetting, balance and centrifuge, repeat the above steps 3 times, remove the supernatant and add 5 mL of fresh LB liquid medium to each tube to obtain the concentrated culture medium of the strain.

[0034] (3) An immobilization and embedding system was prepared according to the volume ratio of concentrated culture medium of the strain, 3% sodium alginate solution and skim milk of 1:1:1. First, 10 mL of 3% sterile sodium alginate solution (sterilized at 121℃ for 30 min) was slowly added to 10 mL of concentrated culture medium of the strain obtained in the second step. After stirring evenly, 10 mL of sterile skim milk (sterilized at 115℃ for 15 min) was slowly added and stirred for 5 min to make it fully mixed, thus preparing the immobilization and embedding system.

[0035] (4) Using a 4.5 gauge sterile syringe needle, 30 mL of the immobilized encapsulation system was drawn and slowly added dropwise at a rate of 60-150 drops to 60 mL of 0.15 mol / L sterile CaCl2 solution (sterilized at 121℃ for 30 min) to obtain immobilized encapsulated particles. The immobilized encapsulated particles were sterilely stored at 4℃ for 18 h, and then washed three times with 0.85% sterile saline to complete the preparation of the immobilized encapsulated microcapsule bacterial agent (…). Figure 1 ).

[0036] 2) Method for testing the viable count of microencapsulated bacterial agents Weigh 1.0 g of the immobilized microcapsule bacterial agent into a sterile 10 mL centrifuge tube, and add 9 mL of 0.2 mol / L sterile sodium citrate solution. The dilution gradient is 10. -1 Shake the mixture on a shaker for 5-10 minutes to fully dissolve the embedded particles. After thorough mixing, transfer 1 mL of the bacterial solution to a sterile centrifuge tube and add 9 mL of sterile sodium citrate solution. The dilution gradient at this point is 10. -2 Repeat the above steps to obtain a dilution factor of 10. -6 Bacterial solution. Select 10 -6 The viable cell count was performed using a gradient method. 20 μL of bacterial suspension was pipetted into the center of LB solid medium and spread evenly. Three replicates were set up for each strain. The culture was sealed with sealing film and incubated upside down in a 28℃ incubator for 24–48 h. After incubation, the colonies were counted (Table 2). The average number of colonies from the three replicates for each strain was taken as the viable cell count. The formula for calculating the viable cell count is as follows: Effective viable count (CFU / g) = (number of colonies per mL of diluted bacterial culture medium x dilution factor) / sample mass (g).

[0037] Table 2 Effective viable bacterial counts for each immobilized encapsulated microcapsule agent

[0038] Note: Crossiella equi Taking JCM 12685 as an example, 49 single colonies represent the microorganisms contained in 20 μL of bacterial culture, diluted 10... -6 The next step should have been to take 1 mL to check the colony count, but only 20 μL was actually taken, a reduction of 50 times. Therefore, the number of viable bacteria per gram of microcapsule is 49. 50 10 6 =2.45×10 9 .

[0039] Example 5: Potted Plant Experiment Soil materials for the pot experiment were collected from the Caoxinzhuang Experimental Farm of Northwest A&F University. After passing the soil through a 2 mm sieve, it was packaged into mushroom bags at 500 g per bag and sterilized at 121℃ for 1 h. 1 g of microcapsule inoculum prepared from a single strain was weighed to form two synthetic bacterial groups. The two synthetic bacterial groups were mixed separately and then inoculated into the mushroom bags in a clean bench. The tops were sealed and incubated in a greenhouse for 3 days.

[0040] The drought-resistant soybean variety Jidou 12 was used as the plant material. During incubation, the seeds were sterilized and germinated. When the roots reached approximately 1 cm in length, they were inoculated into mushroom bags in a clean bench, with 3 seedlings planted per bag and 30 mL of sterile water added using a syringe. During greenhouse cultivation, a 16-hour light-8-hour dark cycle was maintained daily. When the seedlings developed their first pair of true leaves, two weaker seedlings were removed from the clean bench, leaving only one healthy seedling at a similar growth stage to the soybeans in the other mushroom bags for subsequent experiments.

[0041] Soil moisture control. Water treatment began after the soybeans developed their first true leaves, with irrigation (70%–80% relative soil moisture content) and drought treatment (40%–50% relative soil moisture content). Soil relative moisture content was measured every two evenings using a soil moisture meter, and the moisture level was replenished accordingly to maintain the desired gradient. Samples were collected after approximately 30 days when the plants reached their vigorous vegetative growth stage, and intact plants were used for phenotypic analysis. Results are shown below. Figure 2 and Figure 3 .

[0042] This experiment included two factors: water treatment and microbial inoculation. Water treatment included watering and drought. Microbial inoculation included synthetic microbial community S1 (SynCom1), synthetic microbial community S2 (SynCom2), and sterile water (CK). Each treatment was replicated six times, for a total of 36 bags.

[0043] Example 6: Determination of Soybean Indicators Plant growth indicators were determined. The chlorophyll content (SPAD) of soybean plants was measured using a portable chlorophyll meter (model: SPAD-502, Japan), with four replicates per plant. Soybean plants were removed from the mushroom bags, their roots were washed, and dried with absorbent paper. Plant height and root length were measured using a ruler. The soybean plants were divided into aboveground and belowground parts using scissors. The aboveground fresh weight and belowground fresh weight were accurately weighed using a balance, placed in envelopes, and blanched in an oven at 105℃ for 1 hour, followed by drying at 70℃ to constant weight. The aboveground dry weight and belowground dry weight were then measured.

[0044] Figure 4 The results of phenotypic analysis of maize plants; Figure 4 The results showed that, compared with the uninoculated control group, inoculation with synthetic microorganisms increased the SPAD value of maize leaves. Under drought conditions, the SPAD value increased by 5.08% and 8% after inoculation with SynCom1 and SynCom2, respectively; under normal irrigation conditions, the SPAD value increased by 3.86% and 4.29%, respectively. Figure 4 Results showed that inoculation with synthetic microbial communities increased maize plant height. Under drought conditions, inoculation with SynCom1 increased plant height by 4.32%; under normal irrigation conditions, inoculation with SynCom2 increased plant height by 1.94%. Figure 4 Results showed that inoculation with synthetic microbial communities increased root length in maize. Under drought conditions, root length increased by 18.03% and 27.88% after inoculation with SynCom1 and SynCom2, respectively. Figure 4 The results showed that inoculation with synthetic microbial communities increased the aboveground fresh weight of maize. Under drought conditions, the aboveground fresh weight increased by 28.26% and 17.20% after inoculation with SynCom1 and SynCom2, respectively; under normal irrigation conditions, the aboveground fresh weight increased by 63.13% and 53.73%, respectively. Figure 4 The results showed that inoculation with synthetic microbial communities increased the fresh weight of the underground parts of maize. Under drought conditions, the fresh weight of the underground parts increased by 29.12% and 32.51% after inoculation with SynCom1 and SynCom2, respectively. Under normal irrigation conditions, the fresh weight of the underground parts increased by 34.12% and 27.04%, respectively. Figure 4The results showed that inoculation with synthetic microbial communities increased the aboveground dry weight of maize. Under drought conditions, the aboveground dry weight increased by 35.36% and 29.91% after inoculation with SynCom1 and SynCom2, respectively; under normal irrigation conditions, the aboveground dry weight increased by 87.0% and 70.0%, respectively. Figure 4 The results showed that inoculation with synthetic microbial communities increased the underground dry weight of maize. Under drought conditions, the underground dry weight increased by 48.15% and 45.68% after inoculation with SynCom1 and SynCom2, respectively; under normal irrigation conditions, the underground dry weight increased by 38.89% and 40.0%.

[0045] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A synthetic microbial community that enhances the drought resistance of cultivated soybeans, characterized in that, The synthetic bacterial flora is composed of equal parts of immobilized microcapsule agents of Crossiella equi JCM 12685, Pseudaminobacter granuli LMG 29567, Devosia sp. JCM 28289, Agromyces sp. JCM 28256, Bacillus mojavensis ATCC 51516, Streptomyces sp. ATCC 39343, Streptomyces sp. ATCC 25607, and Microbacterium yannicii LMG 25521; or of Crossiella equi JCM 12685, Pseudaminobacter granuli LMG 29567, Devosia sp. JCM 28289, Agromyces sp. JCM 28256, Bacillus sarachidis GDMCC 812564, and Streptomyces tauricus ATCC. The microcapsule preparation was composed of equal amounts of immobilized microcapsules of 27470, Priestia megaterium DSM 110117, and Paenibacillus sp. DSM 110293; The effective viable counts of the immobilized microcapsule bacterial agents containing *Crossiella equi* JCM 12685, *Pseudaminobacter granuli* LMG 29567, *Devosia* sp. JCM 28289, *Bacillus mojavensis* ATCC 51516, *Agromyces* sp. JCM 28256, *Streptomyces* sp. ATCC 39343, *Streptomyces* sp. ATCC 25607, *Microbacterium yannicii* LMG 25521, *Bacillus arachidis* GDMCC 812564, *Streptomyces tauricus* ATCC27470, *Priestia megaterium* DSM 110117, and *Paenibacillus* sp. DSM 110293 were 2.45 × 10⁻⁶. 9 2×10 8 8.5×10 8 8.5×10 8 1.5×10 8 1.55×10 9 1×10 8 7.5×10 8 1×10 9 2×10 8 2.1×10 9 2.5×10 8 CFU / g.

2. The synthetic microbial community for enhancing drought resistance in cultivated soybeans according to claim 1, characterized in that, The method for preparing the immobilized encapsulated bacterial agent is as follows: The viable bacterial count reaches 1×10⁻⁶. 8 The bacterial culture was concentrated 14 times to obtain a concentrated culture medium of the strain. The concentrated culture medium of the strain, 3% sodium alginate solution, and skim milk were mixed in equal volumes to prepare an immobilization and embedding system. The immobilization and embedding system was added dropwise to a 0.15 mol / L sterile CaCl2 solution and sterilized at 4°C for 18 h. After washing three times with 0.85% sterile saline, the immobilized and embedded microcapsule bacterial agent was obtained.

3. The application of the synthetic microbial community as described in claim 1 or 2 in improving the drought resistance of cultivated soybeans.

4. The application of the synthetic microbial community as described in claim 1 or 2 in increasing soybean biomass.

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