Bacillus atrophaeus Q4 for promoting growth of lespedeza and improving abundance of probiotic microbial population and application of bacillus atrophaeus Q4

Abstract

The invention discloses a high-efficiency lespedeza growth-promoting bacillus Q4 (Bacillus atrophaeus) capable of improving the abundance of dominant bacteria and a preparation method of the high-efficiency lespedeza growth-promoting bacillus Q4. Belongs to the technical field of microorganisms. According to the bacillus atrophaeus Q4 provided by the invention, the conversion from total-effect nutrients to effective nutrients is improved, the consumption of lespedeza to soil nutrients is enhanced, and the abundance of dominant strain groups is increased, so that the effect of promoting the growth of lespedeza is achieved. After the bacillus atrophaeus Q4 provided by the invention is applied, the soil enzyme activity is remarkably improved, the conversion of available nutrients in soil is remarkably enhanced, and the nutrient consumption capability of lespedeza is enhanced. By applying the bacillus atrophaeus Q4, growth and development of lespedeza are promoted, the content of soil hydrolytic nitrogen and available phosphorus is remarkably increased, conversion to soil nutrients is improved, and the conductivity and organic carbon are increased to the maximum extent and are remarkably increased by 142.77% and 64.26% respectively. In the genus level, after being treated by the bacillus atrophaeus Q4, the bacillus (Bacillus) is obviously increased from 0.84% to 2.47%, and the average relative abundance of the pseudomonas (Fictibacillus) is obviously increased from 0.59% to 1.16%. By inoculating the Q4 inoculant, the structure of a soil colony is greatly improved, the relative abundance of a dominant flora is influenced, and the obvious increase of the relative abundance of Bacillus and Fictibacillus is possibly an important factor for promoting plant growth.

Description

Technical Field

[0001] The invention relates to Bacillus atrophaeus Q4 (Bacillus atrophaeus) which can promote the growth of Lespedeza and improve the abundance of probiotic microorganism population, and belongs to the technical field of microorganisms. Background Art

[0002] The pace of infrastructure construction such as mineral resource development, road network construction, water conservancy projects and industrial bases is accelerating, and the problem of exposed rock slopes has become increasingly prominent, exacerbating the local ecological environment soil erosion, air pollution and biodiversity reduction. If environmental governance is not strengthened in time, these damages will have an irreversible impact on the environment. The problem of exposed rock slopes is one of the environmental challenges that need to be solved urgently. Ecological environmental restoration is an important measure to protect the environment and maintain social stability, and it is a necessary condition for improving the ecological environment. At present, in order to improve the efficiency of restoration and consolidate the results of restoration, people inevitably need to use pesticides and fertilizers during plant growth. However, due to the long-term application of fertilizers, certain elements in the soil continue to accumulate, causing changes in its physical and chemical properties, thereby endangering food security. Therefore, efficient and greening restoration of exposed rock slopes is a major issue that urgently needs to be solved.

[0003] Microbial agents can degrade and inhibit the secretions of pathogens in the soil, effectively reduce the growth and spread of pathogens, provide a healthy growth environment for crops, and promote the proliferation of beneficial microorganisms in the soil. These beneficial microorganisms can compete with pathogens for nutrients and space, further inhibit the growth of pathogens, and thus achieve the effect of biological control; at the same time, the microorganisms in microbial agents can decompose organic matter in the soil, increase soil organic matter and porosity, break soil compaction, and promote the formation of aggregate structure, thereby improving soil structure and improving soil water retention and heat preservation capacity; in addition, some agents with phosphorus dissolving effect can increase the content of nutrients such as phosphorus in the soil that can be absorbed and utilized by plants. Therefore, in-depth exploration of microbial agents that have a positive role in promoting plant growth and development is of indispensable importance for enriching the research on microbial fertilizers.

[0004] Soil microorganisms are one of the most diverse and species-rich biological groups on land. They have a significant impact on ecosystems such as forests, grasslands, wetlands and farmlands, and play an important role in the entire biogeochemical cycle. The Qinghai-Tibet Plateau is one of the key areas for global biodiversity research due to its high altitude, strong radiation, low oxygen content, large temperature difference between day and night, and unique water and heat distribution pattern. Its strong topographic changes have formed a unique and diverse climate in the region, nurtured unique microbial resources, and promoted the research and development of microorganisms in extreme habitats.

[0005] Lespedeza has become an important candidate plant for ecological restoration of exposed slopes due to its strong tolerance and biological nitrogen fixation characteristics. However, the slope has poor three-dimensional conditions, insufficient nitrogen, phosphorus and potassium in the soil, and it is difficult for plants to grow. Although traditional fertilizer application methods can see results in the short term, they will damage the ecological environment in the long run, and excessive fertilization may also reduce the quality of forests. In contrast, PGPR microbial fertilizer, as a new type of environmentally friendly fertilizer in recent years, is pollution-free and quite popular.

[0006] Therefore, in-depth research and screening and configuration of PGPR microbial agents with significant growth-promoting effects on Lespedeza from the soil of the Qinghai-Tibet Plateau have important practical significance for promoting the development of pollution-free biological fertilizers, helping to give full play to the potential advantages of microbial fertilizers and thus promote the sustainable development of agricultural and forestry production. Summary of the invention

[0007] [Purpose of the invention]

[0008] The present invention aims to screen out a strain that promotes the growth of Lespedeza from the Qinghai-Tibet Plateau and prepare a bacterial agent that promotes the growth of Lespedeza, so as to provide a solution for improving the ecology of exposed slopes in my country.

[0009] [Technical solution]

[0010] In order to solve the above technical problems, the present invention discloses a method for promoting the growth of Lespedeza chinensis, using Bacillus atrophaeus Q4 as a bacterial fertilizer, and the preservation number is CCTCC NO:M 20241237.

[0011] The Bacillus atrophaeus Q4 of the present invention is isolated from a soil sample in Baqing County, Nagqu City, Tibet Autonomous Region, and is stored in a -80 degree Celsius refrigerator in the Soil and Water Conservation Laboratory of Nanjing Forestry University, and is deposited in the China Center for Type Culture Collection, address: Wuhan University, Wuhan, China. The deposit number is CCTCC NO: M20241237, and the deposit date is June 17, 2024.

[0012] The present invention also provides a method for improving the abundance of beneficial microorganisms, using Bacillus atrophaeus Q4 (Bacillus atrophaeus.Q4) as a bacterial fertilizer, and the preservation number is CCTCC NO:M 20241237.

[0013] The present invention also provides an application of Bacillus atrophaeus Q4 in promoting the production of Lespedeza plants. The Bacillus atrophaeus Q4 is used as a bacterial fertilizer and the deposit number is CCTCC NO:M 20241237.

[0014] The present invention also provides an application of Bacillus atrophaeus Q4 in enhancing the utilization of soil nutrients by Lespedeza and improving the abundance of beneficial microbial populations, and Bacillus atrophaeus Q4 is applied as a bacterial fertilizer.

[0015] Furthermore, the microbial agent of the present invention is prepared according to the following steps and applied to the Lespedeza potted plants:

[0016] 1) Pick a cell of Bacillus atrophaeus Q4 from the well-preserved slant and inoculate it into LB agar solid medium and activate it at 28°C for 48 hours.

[0017] 2) Use an inoculation loop to pick up a loop of bacterial slurry from the activated Bacillus atrophaeus Q4 strain and add it to LB liquid culture medium. Keep the culture medium at 28° C. and 200 rpm for 24 hours to prepare the seed solution.

[0018] 3) Inoculate the seed solution at a 5% inoculum into LB liquid medium for amplification culture, and culture at 28°C, 200 rpm on a shaker for 2-3 days. Dilute with sterile water or continue fermentation to ensure that the bacterial solution OD 600 When the pH is 0.8-1.2, the fermentation liquid is obtained.

[0019] 4) Dilute the above fermentation liquid 100 times with sterile water and add it to the soil at the root of Lespedeza potted plants, with 100 mL of the diluted liquid per pot.

[0020] 5) The control was treated with an equal volume of sterile water.

[0021] Beneficial Effects

[0022] The present invention provides a microbial agent that can promote the growth of Lespedeza serrata. The microbial agent is applied to Lespedeza serrata plants to effectively increase the biomass of the underground part of Lespedeza serrata and promote the rooting and development of Lespedeza serrata, and the development prospect is promising. Specifically:

[0023] On the growth index of Lespedeza

[0024] After the Lespedeza seedlings were inoculated with PGPR fungicide, compared with the CK group, the plant height increased by 62.50%, the ground diameter increased by 52.08%, the fresh weight of the aboveground part increased by 106.25%, the dry weight of the aboveground part increased by 181.44%, the fresh weight of the underground part increased by 260.87%, the dry weight of the underground part increased by 67.14%, and the total biomass increased by 133.53%; the root length, root surface area, average diameter, root volume, number of root tips, and number of tillers increased by 206.37%, 223.28%, 9.89%, 244.42%, 227.58%, and 461.25% respectively compared with the CK treatment.

[0025] On the physical and chemical properties of rhizosphere soil of Lespedeza

[0026] Compared with the CK group, the soil hydrolyzed nitrogen in the Q4 bacterial agent treatment group increased by 48.19%; the available phosphorus increased by 43.55%; the available potassium content increased by 9.15%; the soil electrical conductivity increased by 64.26%; and the organic matter content increased the most, up to 142.77%.

[0027] In the abundance of soil microbial populations in the roots of Lespedeza

[0028] At the phylum level, compared with the CK group, the abundance of Proteobacteria and Firmicutes in the Q4 group increased significantly, by 17.63% and 87.40%, respectively; at the genus level, the abundance of dominant species increased under the inoculation of Q4 strain, which reduced the diversity of soil microorganisms. Compared with CK, the average relative abundance of Bacillus increased significantly from 0.84% ​​to 2.47% under Q4 treatment, the average relative abundance of Flavobacterium increased from 1.03% to 1.63%, the average relative abundance of Pseudomonas increased significantly from 0.59% to 1.16%, and the Pseudomonas increased from 0.49% to 1.07%.

[0029] It can be seen from the above technical scheme that the present invention discloses a microbial agent for promoting the growth of Lespedeza and increasing the abundance of probiotic microbial populations. The technical effect achieved is that the microbial agent provided by the present invention promotes the growth of Lespedeza plants after application, especially promotes the underground biomass and root system of Lespedeza plants; increases the relative abundance of Bacillus and Fictibacillus in the soil roots of Lespedeza, so that the plant's rooting and soil fixing ability is effectively exerted. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the present invention are briefly introduced below.

[0031] Figure 1 This is an evolutionary tree diagram of the Bacillus atrophaeus Q4 strain provided by the present invention.

[0032] Figure 2 This is a colony diagram of Bacillus atrophaeus Q4 (LB solid culture medium) provided by the present invention.

[0033] Figure 3 This is a growth curve diagram of Bacillus atrophaeus Q4 provided by the present invention.

[0034] Figure 4 This is a schematic diagram of the phosphorus solubilization ability of Bacillus atrophaeus Q4 provided by the present invention for organic phosphorus and inorganic phosphorus at different temperatures.

[0035] Figure 5 This is a schematic diagram of the changes in plant height and ground diameter of Lespedeza chinensis after being treated with the control group and the Bacillus atrophaeus Q4 strain provided by the present invention.

[0036] Figure 6 This is a schematic diagram of the changes in biomass indicators of Lespedeza bicolor after being treated with the Bacillus atrophaeus Q4 strain provided by the present invention.

[0037] Figure 7 This is a schematic diagram of the changes in soil physical and chemical properties caused by Bacillus atrophaeus Q4 provided by the present invention.

[0038] Figure 8 This is a schematic diagram of the effects of the photosynthetic pigments of Lespedeza plants on the control group and the plants treated with Bacillus atrophaeus Q4 strain provided by the present invention.

[0039] Fig. 9 The invention discloses the effects of the control group provided by the invention and the soil treated with Bacillus atrophaeus Q4 strain on the enzyme activity of potted soil.

[0040] Fig.10 This is a schematic diagram of the composition of the microbial community at the family level in the control group and the potting soil treated with Bacillus atrophaeus Q4 provided by the present invention.

[0041] Fig.11 This is a schematic diagram of the composition of the microbial community at the genus level in the control group and the potting soil treated with Bacillus atrophaeus Q4 provided by the present invention.

[0042] FIG. 12 is a schematic diagram of the analysis of bacterial communities and environmental factors in Lespedeza potted plants in the control group and potted soil treated with Bacillus atrophaeus Q4 provided by the present invention.

[0043] Fig.13 The function of Lespedeza bicolor under different treatments is predicted based on the KEGG database in the control group provided by the present invention and the potting soil treated with Bacillus atrophaeus Q4.

[0044] Fig.14 This is a schematic diagram of Welch's t test for the control group provided by the present invention and the group treated with Bacillus atrophaeus Q4 strain. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] The raw materials and reagents involved in the examples are all obtained from commercial channels, and there is no requirement for their brands. All methods not mentioned are commonly used experimental methods. Bacillus atrophaeus Q4 was isolated and screened by this laboratory from the soil of the Qinghai-Tibet Plateau, and is preserved by the China Center for Type Culture Collection (CCTCC). The address of the preservation unit is Wuhan University, Luojia Mountain, Bayi Road, Wuchang District, Wuhan City, Hubei Province, China. The preservation number is CCTCC NO: M 20241237, and the preservation date is June 17, 2024.

[0047] Example 1

[0048] 1. Sample source

[0049] The strains were screened from soil samples from Baqing County, Nagqu City, Tibet Autonomous Region, China. After the samples were collected, they were placed in a 4°C incubator and brought back to the laboratory for storage in a -80°C refrigerator, and the soil microorganisms were isolated within 48 hours.

[0050] 2Separation and screening

[0051] (1) NA solid medium: peptone 10 g, beef extract powder 3 g, sodium chloride 5 g, agar 15 g, 1000 ml deionized water, pH 7.2-7.4.

[0052] (2) LB liquid medium: peptone 10 g, yeast extract powder 5 g, sodium chloride 5 g, deionized water 1000 mL, pH 7.2.

[0053] (3) Montana organophosphorus medium: glucose 10 g, ammonium sulfate 0.5 g, sodium chloride 0.3 g, potassium chloride 0.3 g, magnesium sulfate heptahydrate 0.3 g, ferrous sulfate heptahydrate 0.03 g, manganese sulfate tetrahydrate 0.03 g, calcium carbonate 5.0 g, lecithin 0.3 g, agar 20 g, pH 7.0-7.5, distilled water 1000 mL.

[0054] (4) Montana inorganic phosphate medium: glucose 10 g, ammonium sulfate 0.5 g, sodium chloride 0.3 g, potassium chloride 0.3 g, magnesium sulfate heptahydrate 0.3 g, ferrous sulfate heptahydrate 0.03 g, manganese sulfate tetrahydrate 0.03 g, tricalcium phosphate 5.0 g, agar 20 g, pH 7.0-7.5, distilled water 1000 mL.

[0055] Take 0.1g of soil and place it in a conical flask containing 100ml LB liquid medium and place it on a shaker. After 3 days, use the plate dilution method to culture in a 28℃ incubator with NA solid medium for about 2 to 5 days, pick a single colony, repeatedly streak and purify, and inoculate the obtained strains on solid medium plates and store them in a 4℃ refrigerator to obtain pure strains. According to the main biological characteristics, bacteria Q4, Q7 and YG1 were obtained.

[0056] Example 2

[0057] Investigate the growth-promoting effect of the fungus. Combined with potted plant experiments, the selected fungi were applied to the seedling soil to explore their potential effects in production applications.

[0058] 1. Preparation of inoculants

[0059] 1.1 Culture medium

[0060] (1) The composition and content of nutrient agar solid medium are as follows: peptone 10 g, beef extract powder 3 g, sodium chloride 5 g, agar 15 g, deionized water 1000 ml, pH 7.2-7.4.

[0061] (2) The composition and proportion of LB liquid culture medium are as follows: add 950 ml of deionized water, 10 g of tryptone, 5 g of yeast extract powder, and 5 g of sodium chloride into a container, shake the container until the solute is dissolved, adjust the pH of the solution to 7.4 with 5 mol / L sodium hydroxide, and make up to 1 L.

[0062] 1.2 Preparation of inoculants

[0063] (1) One cell of Bacillus atrophaeus Q4 was selected from each well-preserved slant and inoculated into nutrient agar solid medium and activated at 25°C for 48 h.

[0064] (2) Use an inoculation loop to pick up a loop of bacterial slurry from the activated strain and add it to LB liquid culture medium. Keep the culture medium at 25°C and 200 rpm for 24 h to prepare the seed solution.

[0065] (3) Dilute the seed solution by adding sterile water or continue fermenting until the fermentation liquid OD 600 The concentration is in the range of 0.8 to 1.2, and then sealed and stored in a refrigerator at 4°C for later use.

[0066] (4) The control group was treated with an equal volume of sterile water diluted 100 times.

[0067] 2. Planting of Lespedeza seedlings

[0068] The potted plants were made of the leguminous plant Lespedeza as the test object. After soaking the seeds of Lespedeza in pure water for 12 hours, the water was filtered and the seeds were soaked in 5% sodium hypochlorite solution for 10 minutes for disinfection, then washed with pure water until odorless, and placed in a seedling cup for germination for a week. After the seeds germinated into seedlings, the seedlings with similar height and growth were transplanted into potted plants, and one seedling was planted in each pot. The soil used for potted plants came from Baqing County, Nagqu City, Tibet Autonomous Region, China. After the Lespedeza seedlings grew well, the prepared bacterial agent was applied, with the application of the bacterial agent as the first day. After three months, the samples were destroyed and used for experiments.

[0069] Determination and methods of potted plant indicators

[0070] For plants: vernier calipers and tape measures were used to measure the diameter at breast height and plant height of the seedlings; the dry weight of Lespedeza was measured by drying and sterilizing; the photosynthetic data of Lespedeza leaves were measured using a LI-6400 portable photosynthetic meter (Li-Cor Inc. USA), and the chlorophyll content of plant leaves was measured using a mixed liquid extraction method; the root morphological indicators of the tree seedlings, such as root length, root surface area, root volume and average root diameter, were measured and analyzed using a root analysis system (WinRHIZO 2013).

[0071] For potting soil: soil available phosphorus was determined by acid dissolution-molybdenum antimony countercolorimetry; soil alkaline nitrogen was determined by alkaline diffusion method; available potassium content was determined by flame photometry after extraction with ammonium acetate; soil organic matter was determined by potassium dichromate volumetric method; soil hydrolysis content was determined by alkaline diffusion method; soil pH was determined by mettlertoledo pH meter (water-soil ratio was 5:1).

[0072] The results show that:

[0073] Effects of treatment with fungal agents on the growth of Lespedeza chinensis

[0074] Note: P<0.05.

[0075] Depend on Figure 5 , Figure 6 As shown in Table 1, compared with the control group, Q4 treatment significantly increased the plant height of Lespedeza (P < 0.05, the same below), and its plant height increased by 62.50%; from the perspective of the ground diameter of Lespedeza, Q4 was the optimal treatment, and it significantly increased by 52.08% compared with the control group. From the perspective of the underground part of Lespedeza, Q4 was the optimal treatment, and the dry weight significantly increased by 67.14% compared with the control group. Overall, each bacterial agent treatment can increase the plant height, ground diameter, and underground dry weight of Lespedeza, but the promotion effect is different.

[0076] Table 1 Effects of bacterial agent treatment on growth indicators of Lespedeza

[0077] Effects of bacterial strains on soil physical and chemical properties

[0078] Note: P<0.05.

[0079] Depend on Figure 7 As shown in Table 2, the application of Bacillus atrophaeus Q4 provided by the present invention significantly enhanced the conversion of soil available nutrients and enhanced the nutrient consumption capacity of Lespedeza. The application of Bacillus atrophaeus Q4 promoted the growth and development of Lespedeza, significantly increased the content of soil hydrolyzed nitrogen and available phosphorus, and increased the conversion to soil nutrients, among which organic carbon increased the most, significantly increasing by 64.26%. The pot experiment showed that Bacillus Q4 can effectively utilize nitrogen, phosphorus and potassium in the soil without changing the soil pH, increase the soil organic carbon content, thereby promoting the growth of Lespedeza and improving soil fertility.

[0080] Table 2 Effects of microbial treatment on soil physical and chemical properties

[0081] Example 3

[0082] Investigate the effect of strains on the composition of microbial communities.

[0083] The collected and sorted Lespedeza rhizosphere soil samples were sent to Guangzhou Kidio Co., Ltd. for sequencing. The microbial diversity in the potted soil was analyzed by high-throughput sequencing methods to explore the microbial community composition of the potted soil.

[0084] Depend on Fig.10 It can be seen that at the phylum level, the top ten dominant bacterial groups in terms of soil bacterial abundance in Lespedeza chinensis are Proteobacteria, Bacteroidota, Chloroflexi, Acidobacteriota, Planctomycetota, Verrucomicrobiota, Actinobacteriota, Firmicutes, Cyanobacteria, and Gemmatimonadota. Compared with the CK group, the abundance of Proteobacteria and Firmicutes in the Q4 group increased significantly, by 17.63% and 87.40%, respectively.

[0085] At the genus level, the abundance of dominant species at the genus level increased after inoculation with the Q4 strain, which reduced the diversity of soil microorganisms, which is consistent with the results of the α analysis shown in Table 3. Fig.11It can be seen that compared with CK, the use of Q4 microbial agent increased the relative abundance of Bacillus, Flavisolibacter, Terrimonas, Fictibacillus, Aquicella, and Pseudomonas. Under Q4 treatment, the average relative abundance of Bacillus increased significantly from 0.84% ​​to 2.47%, the average relative abundance of Flavisolibacter increased from 1.03% to 1.63%, the average relative abundance of Fictibacillus increased significantly from 0.59% to 1.16%, and Pseudomonas increased from 0.49% to 1.07%. In general, the inoculation of Q4 microbial agent greatly improved the soil colony structure and affected the relative abundance of the dominant bacterial community. The significant increase in the relative abundance of Bacillus and Fictibacillus may be an important factor in promoting plant growth.

[0086] Table 3 Alpha diversity index of rhizosphere soil bacterial community in potted plants

[0087] The present invention first uses CCA canonical correspondence analysis to construct a CCA diagram between the microbial community, samples and environmental factors at the genus level, and uses a correlation heat map to directly display the Pearson correlation between environmental factors and species, thereby explaining the impact of environmental factors on the structure of the microbial community.

[0088] Figure 12(a) shows the CCA analysis of rhizosphere soil bacterial communities, samples and environmental factors of Lespedeza chinensis. The two axes CCA1 and CCA2 explained 79.45% of the changes in bacterial community structure. At the genus level, environmental factors SOC, EC, pH, AK, AP, and HN were positively correlated with the Q4 inoculant treatment group, indicating that inoculation of inoculants helped to increase the release of soil nutrients; Figure 12(b) shows that the Bacillus genus was significantly positively correlated with AP and SOC (P<0.05), and was positively correlated with HN, AK, and EC, which significantly affected the relative abundance of the Bacillus genus.

[0089] Depend on Fig.13It can be seen that there are significant differences in the relative abundance of bacterial functional genes in Lespedeza soil samples under different treatments. Among them, the relative abundance of the four major categories of genes in the Q4 treatment group, namely metabolism, genetic information processing, cellular processing, and environmental information processing, are all higher than those in the sterile CK group, and the relative abundance of metabolites involved in metabolism accounts for the largest proportion.

[0090] Welch's t test ( Fig.14 ) found that the abundance of secondary functional genes such as Metabolism of cofactors and vitamins, Carbohydrate metabolism, and Amino acid metabolism increased under Q4 treatment compared with CK treatment.

[0091] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0092] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one 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 present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for promoting the growth of Lespedeza chinensis, characterized in that: Bacillus atrophaeus Q4 was used as bacterial fertilizer, and its deposit number is CCTCC NO:M 20241237.

2. A method for increasing the abundance of beneficial microorganisms, characterized in that: Bacillus atrophaeus Q4 was used as bacterial fertilizer, and its deposit number is CCTCC NO:M 20241237.

3. An application of Bacillus atrophaeus Q4 in promoting the production of Lespedeza plants, characterized in that: Bacillus atrophaeus Q4 was used as bacterial fertilizer, and its preservation number was CCTCC NO:M 20241237.

4. An application of Bacillus atrophaeus Q4 in enhancing the utilization of soil nutrients by Lespedeza and increasing the abundance of beneficial microbial populations. Bacillus atrophaeus Q4 was used as bacterial fertilizer.

5. The use according to claim 4, characterized in that: After treatment with Bacillus atrophaeus Q4, the contents of hydrolyzed nitrogen and available phosphorus in the soil increased significantly, and the conversion to soil nutrients was enhanced, among which the electrical conductivity and organic carbon increased the most, by 142.77% and 64.26% respectively.

6. The use according to claim 4, characterized in that: After treatment with Bacillus atrophaeus Q4, the abundance of beneficial microbial populations increased significantly. At the genus level, the Bacillus genus increased significantly from 0.84% ​​to 2.47%, and the average relative abundance of Fictibacillus genus increased significantly from 0.59% to 1.16%; at the family level, the abundance of Proteobacteria and Firmicutes increased significantly, increasing by 17.63% and 87.40%, respectively. The significant increase in the relative abundance of Bacillus and Fictibacillus is an important factor in promoting the growth of Lespedeza.

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