Saline-alkali tolerant actinomycete JC and application thereof in saline-alkali resistance and growth promotion of crops

Abstract

The invention provides a strain of halotolerant bacteria of Kocuria (Kocuria) and application of the halotolerant bacteria of Kocuria to growth promotion of corn and wheat under the stress of salt, and particularly provides a strain of halotolerant bacteria of Kocuria (Kocuria) and application of the halotolerant bacteria of Kocuria (Kocuria) to growth promotion of corn and wheat under the stress of salt. The salt-tolerant actinomycete JC is separated from drought saline-alkali soil in Longzhong Gansu Province, grows well in an LB culture medium with the pH value of 8 and containing 30 g / L of NaCl, and is preserved in the China General Microbiological Culture Collection Center on March 17, 2025, and the preservation number is CGMCC No. 33847. The strain has multiple functions of resisting salt and alkali, reducing salt and alkali, producing IAA, fixing nitrogen, dissolving inorganic phosphorus, promoting growth of corn and wheat seedlings and the like. Experiments prove that the strain can reduce salt and alkali by 7.54% and 6.55%, and can significantly relieve saline-alkali stress of crops and promote growth. The method has important application value in the aspects of improving the production capacity of plants in a saline-alkali environment, improving saline-alkali soil and the like.

Description

Technical Field

[0001] The present invention relates to the field of agricultural biotechnology, and in particular to application of salt-alkali tolerant actinomycetes (Kocuriahimachalensis) in salt-alkali resistance and growth promotion of crops. Background Art

[0002] Soil salinization disrupts soil structure, causing soil compaction and impairing aeration and water permeability. Furthermore, salinity-alkalinity stress severely inhibits soil microbial growth, reduces soil enzyme activity, limits aboveground crop growth, and reduces organic carbon input, thereby reducing soil fertility. Soil salinization is particularly severe in arid and semi-arid regions, leading to the degradation of large tracts of arable land and inefficient agricultural production, becoming a major constraint to sustainable agricultural development. Therefore, effectively improving saline-alkaline soils and enhancing crop growth under salinity-alkalinity stress have become critical issues that need to be addressed in global agricultural research and production.

[0003] At present, the improvement methods of saline-alkali land include physical, chemical and biological methods. Among them, biological methods have the advantages of being environmentally friendly, green and sustainable, and low cost. In recent years, salt-alkali tolerant microbial agents can effectively alleviate salt stress and promote crop growth under saline-alkali stress. On the one hand, microbial improvers can release active substances such as organic acids and polysaccharides, thereby reducing the salinity of the soil. At the same time, certain specific metabolites produced by microorganisms can induce plants to produce antioxidants and osmotic protective substances, alleviating the saline-alkali stress suffered by plants. On the other hand, microbial functional agents can promote plant growth by secreting plant growth hormones. Related research mainly focuses on the isolation and application of bacterial strains. There is very little research on the application of actinomycetes to the growth-promoting effect of plants in saline-alkali environments. The present invention discloses an actinomycete strain with multiple functions such as salt-alkali tolerance, salt-alkali reduction, IAA production, nitrogen fixation, inorganic phosphorus decomposition, and promotion of wheat and corn seedling growth. It has important application value in alleviating plant salt-alkali stress and saline-alkali land restoration. Summary of the Invention

[0004] The primary purpose of the present invention is to provide an actinomycete JC that is salt- and alkali-tolerant and can promote the growth of corn and wheat.

[0005] The inventors isolated a salt-tolerant actinomycete (Kocuriahimachalensis) JC from the surface soil of arid saline-alkali loess. The strain grew well in LB medium at pH 8 containing 30 g / L NaCl, and had multiple functions, including salt-alkali tolerance, salt-alkali reduction, IAA production, nitrogen fixation, inorganic phosphorus solubilization, and growth promotion of wheat and corn seedlings. The strain was deposited in the General Microbiology Center of the China Culture Collection Administration, at the Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, with the deposit number CGMCC No. 33847.

[0006] A second object of the present invention is to provide at least one application in salt-alkali tolerance, salt-alkali reduction, nitrogen fixation, phosphate solubilization, and IAA production. The JC strain can tolerate a salt concentration of 10-100 g / L and a pH range of 7-12 at a temperature range of 18-38°C.

[0007] The third object of the present invention is to provide a formulation of a liquid inoculum of salt-tolerant actinomycetes JC.

[0008] Preferably, the formula of the salt-tolerant actinomycete JC liquid inoculant is: JC bacterial suspension, and the auxiliary agent includes one or more of glycerol, trehalose, sodium benzoate, potassium sorbate, sodium chloride, γ-polyglutamic acid, sodium dodecylbenzenesulfonate, and chitin.

[0009] The fourth object of the present invention is to provide the use of a salt-tolerant actinomycete JC liquid inoculant in promoting the growth of saline-alkali soil crops and improving saline-alkali land.

[0010] Preferably, the salt-tolerant actinomycete JC liquid inoculant can promote the growth of the above-ground parts and underground roots of wheat and corn, and can promote the accumulation of chlorophyll and soluble sugar.

[0011] Preferably, the method for using the salt-tolerant actinomycetes JC liquid inoculant is as follows: before planting, dilute the salt-tolerant actinomycetes JC liquid inoculant with sterile water to OD 600 =1.0 Soak the seeds for 24 hours to germinate before sowing, and then apply bacterial suspension regularly.

[0012] Compared with existing technologies, a salt-tolerant actinomycete JC and its application in crop resistance to salt and alkali and growth promotion have the following advantages:

[0013] (1) The salt-tolerant actinomycete JC of the present invention grows well in a culture environment of pH=8 and 30 g / L NaCl, and exhibits high salt-alkali tolerance.

[0014] (2) The salt-tolerant actinomycete JC can reduce the salt and alkali levels by 7.54% and 6.55%, respectively, which can significantly alleviate the salt-alkali stress of crops.

[0015] (3) Salt-tolerant actinomycetes JC can provide nitrogen and phosphorus nutrients that can be absorbed by plants by fixing nitrogen and solubilizing phosphorus, and stimulate root development by secreting IAA, effectively promoting plant growth.

[0016] (4) The salt-tolerant actinomycete JC of the present invention can promote the growth of the aerial parts and root systems of corn and wheat, as well as the accumulation of chlorophyll and soluble sugar content in plants, and has broad application prospects in the research and development of agricultural microbial fertilizers for saline-alkali land. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is the phylogenetic tree of JC strains based on 16s rDNA sequences.

[0018] Figure 2 Figure 3 is the colony morphology of JC strain.

[0019] Figure 3 This is the growth curve of JC strain.

[0020] Figure 4 This is the result of IAA production by JC strain.

[0021] Figure 5 The nitrogen fixation results of JC strain

[0022] Figure 6 The results of inorganic phosphorus decomposition by JC strain

[0023] Figure 7 The growth-promoting effect of JC strain on corn

[0024] Figure 8 This is a statistical bar chart showing the results of JC strain promoting corn growth.

[0025] Figure 9 Statistical bar chart of the effect of JC strain on corn chlorophyll

[0026] Figure 10 Statistical bar chart showing the effect of JC strain on soluble sugar in corn

[0027] Figure 11 The growth-promoting effect of JC strain on wheat

[0028] Figure 12 This is a statistical bar chart showing the results of wheat growth promotion by JC strains.

[0029] Figure 13 Statistical bar chart showing the effect of JC strain on wheat chlorophyll

[0030] Figure 14 Statistical bar chart showing the effect of JC strain on wheat soluble sugar DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention, but the implementation manner of the present invention is not limited thereto.

[0032] The present invention provides a salt-tolerant strain and its application, the deposit number of the strain is CGMCC No. 33847

[0033] The gene is deposited in the General Microbiology Center of China Culture Collection Administration, and the deposit address is Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing.

[0034] Example 1: Isolation, purification and identification of strains

[0035] 1. Isolation and purification of strains

[0036] The topsoil was collected from the bare land of Yanchigou, Anning District, Lanzhou, and transported back to the laboratory after removing impurities. 1g of soil was added to 9ml of sterile water to prepare a soil suspension, which was diluted 10 times to 10 -7 g / ml. Spread 100 μL of each suspension onto a LB solid medium (pH 8, 6% NaCl) plate and incubate at 30°C for 3 days. Pick colonies and purify them by transfer three times. Add 50 μL of the pure culture to 30% glycerol and store at -80°C.

[0037] 2. Identification of strains

[0038] The genomic DNA of strain HF was extracted and amplified by PCR using the universal primers for bacterial 16S rDNA (27F / 1492R) to obtain a sequence of approximately 1500 bp in length. The sequence was aligned in the NCBI database (https: / / blast.ncbi.nlm.nih.gov / Blast.cgi), and a phylogenetic tree was constructed using MEGA X64 ( Figure 1 The sequence has the highest similarity (99.86%) with Actinomycetes (Kocurias p.) JCM 13326.

[0039] Example 2: Colony morphology and growth characteristics

[0040] 1. Colony morphology characteristics

[0041] Pick a single colony and inoculate it on solid LB medium with pH=8 and 6% NaCl. Observe the colony morphology: the colony is spherical, orange-yellow, with a moist surface, a single colony with raised edges and smooth and neat edges. Figure 2 shown.

[0042] 2. Colony Growth Curve

[0043] JC colonies were picked up and placed in LB liquid medium (pH = 8, NaCl 6%), and cultured at 30°C and 180 rpm until OD 600 Transfer 1 ml to fresh LB medium and culture at 30°C with shaking. Use empty LB as control and measure OD every 2 h. 600 Draw a growth curve ( Figure 3 The results showed that the logarithmic growth period was 28-48 h, which provided a reference for the application and large-scale production of this strain.

[0044] Example 3, JC strain function

[0045] 1. Salt and alkali tolerance of JC strain

[0046] (1) Salt tolerance of the strain

[0047] Table 1 Results of salt tolerance test of JC strain

[0048] NaCl concentration (g / L) 0 10 20 30 40 50 60 70 80 90 100 + + + + + + + + + + +

[0049] Note: + indicates that the colony can grow, - indicates that the colony cannot grow

[0050] Pick a single colony of the strain and inoculate it into LB liquid medium (pH = 8, NaCl 6%). Cultivate at 30°C and 180 rpm until the OD value is approximately 1.0. Take 500 μL of the bacterial solution and inoculate it into LB liquid medium with pH = 8 and salt concentration of 0-100 g / L (gradient of 10 g / L). Measure the OD value after 24 hours. 600 The results showed that the strain had excellent salt tolerance.

[0051] (2) Alkali resistance of JC strain

[0052] Pick a single colony of JC strain and inoculate it into LB liquid medium (pH=8, NaCl 6%), and culture it at 30℃ and 180r / min until the OD value is about 1.0. Take 500μL of bacterial solution and inoculate it into LB liquid medium with a salt concentration of 60g / L, pH7-14, and culture under the same conditions. Use blank medium as control and measure OD after 24 hours. 600 The results were repeated three times and the average values ​​were taken as Table 2. The strain can grow normally in the pH range of 7-12 and has excellent alkaline resistance, which provides a basis for the application of this strain in saline-alkali land.

[0053] Table 2 Alkali resistance of JC strain

[0054] pH 7 8 9 10 11 12 13 14 + + + + + + - -

[0055] Note: + indicates that the colony can grow, - indicates that the colony cannot grow

[0056] According to the experimental results of (1) and (2) above, it is shown that the JC strain can grow under high-salt and high-alkali conditions, laying the foundation for the subsequent application of this strain.

[0057] 2. Salt- and alkali-reducing function of JC strain

[0058] (1) Salt-lowering function of JC strain

[0059] Single colonies of the JC strain were inoculated into different LB liquid media (pH 7-12, 6% NaCl) and cultured at 30°C and 180 rpm until the OD value reached approximately 1.0. Every 12 hours, 1 mL of the culture medium was sampled, 5 μL of 10% potassium chromate indicator was added, and the culture was titrated with 0.1 mol / L AgNO₃ until a stable brick-red precipitate appeared.

[0060] According to the formula: C2= (C1 × V1) / V2, calculate Cl - The concentration of C2.

[0061] Where, C1 = concentration of AgNO3 solution (mol / L); V1 = volume of AgNO3 solution consumed during titration (mL); V2 = volume of bacterial solution during titration (mL);

[0062] The C1 content is obtained and the salt reduction rate η is calculated according to the formula 盐

[0063] Calculation formula: η 盐 =(C 2最高 -C 2最低 ) / C 2最高 ×100%

[0064] Among them, C 2最高 is Cl in the culture medium - Concentration before degradation (mol / L); C 2最低 CI in the culture medium - Concentration after degradation (mol / L)

[0065] Table 3 Salt reduction rate results of JC strain

[0066] pH 7 8 9 10 11 12 <![CDATA[Desalination rate η 盐 (%)]]> 0 2.51 7.54 0.26 0 0

[0067] When the initial pH values ​​were 8, 9, and 10, the salt reduction rates of the JC strain were 2.51%, 7.54%, and 0.26%, respectively, indicating that the JC strain had a salt reduction function, thereby alleviating salt stress on plants and promoting plant growth.

[0068] (II) Alkali-reducing function of JC strain

[0069] A single colony of the JC strain was picked and inoculated into LB liquid medium (pH = 8, NaCl 6%) and cultured in a constant temperature shaking incubator at 30°C and 180 r / min. The absorbance of the bacterial solution at 600 nm was measured and the OD value was adjusted to about 1.0. Every 12 h, 0.5 mL of the bacterial solution was taken and centrifuged at 4000 rpm for 5 min. The supernatant was taken to measure the pH value of the bacterial solution before and during the culture. The results are shown in Table 4.

[0070] The alkali reduction rate η is calculated according to the following formula 碱

[0071] Calculation formula: η 碱 =(pH 前 —pH 后 ) / pH 前 ×100%

[0072] Among them, pH 前 is the pH value of the culture medium before fermentation; pH 后 is the pH value of the culture medium after fermentation.

[0073] Table 4 Results of alkali reduction rate of JC strain

[0074] pH 7 8 9 9.5 10 <![CDATA[Alkali reduction rate η 碱 (%)]]> 0.25 0.12 3.11 5.35 6.56

[0075] The alkalinity reduction rates of the JC strain obtained according to the above method are shown in Table 4. As can be seen from the table, the alkalinity reduction rates of the JC strain at initial pH values ​​of 7, 8, 9, 9.5, and 10 were 0.25%, 0.12%, 3.11%, 5.35%, and 6.56%, respectively, indicating that the JC strain has a significant alkalinity reduction function, thereby alleviating the stress of the high alkaline environment on plants and promoting plant growth.

[0076] According to the experimental results of the salt-reducing and alkali-reducing functions of the above-mentioned strain, it is shown that the strain has excellent alkali-reducing and salt-reducing functions, can effectively improve the soil properties of saline-alkali land, alleviate the stress of plants under saline-alkali conditions, and can be used to improve saline-alkali land and promote the growth of plants in saline-alkali land.

[0077] (III) IAA production function of the strain

[0078] Inoculate JC bacteria at an OD600 of approximately 1.0 in LB liquid medium (sterilized at 121°C for 20 minutes) containing 0.5 g / L L-tryptophan and incubate at 30°C and 180 rpm for 24 hours. Take 2 mL of the bacterial solution and centrifuge at 10,000 rpm for 15 minutes. Take 1 mL of the supernatant and add 1 mL of Salkowski colorimetric solution. Incubate in the dark for 30 minutes. Three repeated experiments showed that the solution turned red ( Figure 4 ), indicating that the JC strain has the ability to produce IAA.

[0079] (IV) Nitrogen-fixing function of JC strain

[0080] Select JC colonies and incubate them in LB liquid medium (pH = 8, NaCl 6%) at 30°C and 180 rpm for 24 hours. The bacterial suspension was inoculated onto Axubei nitrogen-free solid medium (three wells per dish: bacterial suspension, uninoculated medium control, and sterile water control) and incubated at 30°C for 7 days. Each treatment was repeated three times. Observe colony formation and, if present, purify and transfer to the third generation. Those that can grow stably in this medium have the ability to fix nitrogen. The results are shown in Figure 1. Figure 5 As shown, the JC strain can grow normally, indicating that it has the ability to fix nitrogen.

[0081] (V) Inorganic phosphorus decomposition ability of JC strain

[0082] Take the JC bacterial suspension and inoculate it into inorganic phosphorus identification medium (three wells per dish: bacterial suspension, uninoculated medium control, sterile water control), add 50 μL to each well, and culture at 30℃ for 7-9 days. Observe the formation of transparent zone. The results show ( Figure 6 ): transparent zone diameter D = 11.61 mm, bacterial liquid well diameter d = 7.95 mm, and D / d = 1.46, indicating that the JC strain has the ability to solubilize inorganic phosphorus. This ability can convert phosphorus in the soil that is difficult for plants to absorb and utilize into a form that can be absorbed and utilized, which is of great significance for improving soil phosphorus availability, promoting plant growth, and improving soil fertility.

[0083] Example 4: Growth-promoting effect of strain JC on crops

[0084] 1. The growth-promoting function of the strain on corn

[0085] Preparation of bacterial suspension: JC strain was inoculated into LB liquid medium (pH = 8, NaCl 6%), cultured at 30 ° C, 180 rpm for 24 h, and resuspended in sterile water after centrifugation to OD 600 =1.0.

[0086] Seed treatment: After disinfecting the "Jin Zhangye 301" corn seeds with 75% ethanol and 2% sodium hypochlorite, rinse with sterile water and immerse in bacterial suspension at 26°C in the dark for 24 hours to germinate.

[0087] Pot experiments were conducted by filling pots with sterilized perlite and vermiculite (2:1) and adding saline-alkali solutions of varying salt concentrations (0, 3, 6, 9, and 12 g / L, pH 8). Eight seeds were sown per pot, with three replicates. The bacterial suspension was applied regularly after seedlings emerged from the soil, while a control group was treated with sterile water. Fresh weight, plant height, and root length were measured after 14 days of incubation.

[0088] The results showed that under the condition of salt concentration of 0-12 g / L, the application of JC strain had a good growth-promoting effect on corn growth. Figure 7 As shown, inoculation with JC strain significantly promoted corn growth. Figure 8 A, B, and C represent the effects of five salt stress treatments on fresh weight, plant height, and root length, respectively. Figure 8 The results showed that the addition of the bacteria increased corn fresh weight (A), plant height (B), and root length (C) under different salt stresses (0-12 g / L). The growth-promoting effect was most significant at a salt concentration of 6 g / L, with fresh weight, plant height, and root length increasing by 31.15%, 78.57%, and 37.21%, respectively.

[0089] Chlorophyll content determination: 2.5 g of corn seedling leaves were placed in a mortar and 5 ml of 95% (v / v) ethanol were added to the slurry. The leaves were then centrifuged at 10,000 rpm for 10 min, and the supernatant was collected. The absorbance of the extract at 665 nm and 649 nm was measured using a UV spectrophotometer. The chlorophyll content was calculated according to the following formula:

[0090] C a =13.95OD 665 -6.88OD 649

[0091] C b =24.96OD 649 -7.32OD 665

[0092] Total chlorophyll content: (mg g -1 FW) = (C a +C b )×V / (1000×FW)

[0093] Among them C a is the chlorophyll a content; C b is the chlorophyll b content, V is the volume of the extract (mL), and FW is the fresh weight of the leaves (g).

[0094] The results are as follows Figure 9 As shown, it can be seen that the addition of JC strains has a positive effect on the increase of chlorophyll content. Under the salt stress conditions of 6 g / L, 9 g / L, and 12 g / L, the chlorophyll content of corn increased by 28.65%, 43.64%, and 57.96%, respectively, after inoculation with the bacterial suspension of the strain.

[0095] Take 0.5-1.0 g of fresh sample, grind it, add 15 mL of distilled water and boil it in a boiling water bath for 20 minutes. After cooling, filter it into a 100 mL volumetric flask, wash the residue and make up the volume. Take 1.0 mL of the extract and add 5 mL of anthrone reagent, boil it in boiling water for 10 minutes, and measure the OD after cooling. 620 The experiment was repeated 3 times. The soluble sugar content was calculated according to the following formula:

[0096] Soluble sugar content (%) = sugar amount obtained from the standard curve (μg) × extract volume (ml) × dilution factor / [volume of sample solution for determination (ml) × sample weight (g) × 10 6 ]×100

[0097] The results of the test are as follows Figure 10 As shown in the results, after adding the bacterial suspension, the soluble sugar content of corn was lower than that of the control group under the five salt concentration gradients, indicating that the addition of bacteria can alleviate the salt stress on corn plants, thereby reducing the soluble sugar content. Among them, under the salt stress conditions of 3 g / L, 6 g / L, 9 g / L, and 12 g / L, after inoculation with the JC strain suspension, the soluble sugar content of corn decreased by 49.30%, 31.26%, 31.76%, and 32.30%, respectively.

[0098] In summary, under saline-alkali stress conditions, the JC strain has a significant growth-promoting effect on corn seedlings.

[0099] 2. The growth-promoting function of the strain on wheat

[0100] Preparation of JC strain bacterial suspension: the same preparation method as the corn experiment.

[0101] Processing of wheat seeds: Select complete, plump and consistent "Longchun 23" wheat seeds, and the rest of the steps are the same as corn.

[0102] The pot experiment and sowing method are the same as corn. The results show that ( Figure 11 ) Under the conditions of salt concentration of 0-12 g / L, the application of JC strain has a good growth-promoting effect on wheat. Figure 12 As shown in the figure, the fresh weight (A), plant height (B) and root length (C) of wheat inoculated with fungi increased under the five salt stress conditions. Under the salt stress conditions of 6 g / L and 12 g / L, the fresh weight of wheat increased by 26.32% and 48.84%, the plant height increased by 51.04% and 22.32%, and the root length increased by 48.03% and 66.55%, respectively.

[0103] The chlorophyll content determination method is the same as that of corn. Figure 13As shown, it can be seen that the addition of bacterial suspension has a promoting effect on the accumulation of wheat chlorophyll content. Under the salt stress conditions of 3 g / L and 12 g / L, the chlorophyll content of wheat increased by 13.61% and 7.23% respectively after inoculation with the bacterial suspension of the strain.

[0104] The method for determining soluble sugar content is the same as that for corn. Figure 14 As shown in the figure, the addition of the bacterial suspension reduced the soluble sugar content of wheat under all five salt concentration gradients compared to the control group, indicating that the addition of the JC strain can alleviate salt stress in wheat plants, thereby reducing the soluble sugar content. Under salt stress conditions of 3 g / L and 6 g / L, the soluble sugar content in wheat seedlings decreased by 42.6133% and 36.0962%, respectively, after inoculation with the JC strain suspension.

[0105] In summary, under saline-alkali stress conditions, the strain has a significant growth-promoting effect on wheat seedlings.

Claims

1. A salt- and alkali-tolerant actinomycete strain ( Kocuriahimachalensis sp.) JC, characterized by, The deposit number of the strain is CGMCC No. 33847, and the deposit address is Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing. The contact number is: 010-64807355.

2. The strain JC according to claim 1, characterized in that The 16S rDNA gene sequence is shown in SEQ ID NO:

1. The 16S rRNA gene sequence of the JC strain provided by the present invention is a naturally obtained mutated structural gene, and the mutated structural gene and the 16S rRNA gene sequence of the JC strain are derived from the same species.

3. The JC strain according to claim 1 or 2, characterized in that The JC strain can tolerate a salt concentration of 10-100 g / L and a pH range of 7-12 in a temperature range of 18-38°C.

4. Use of the strain JC according to any one of claims 1 to 3 in at least one of salt-alkali tolerance, salt-alkali reduction, nitrogen fixation, phosphate solubilization, and IAA production.

5. A liquid bacterial agent prepared using the actinomycete JC as described in any one of claims 1 to 3, and its progeny, mutants, and derivatives.

6. The bacterial agent according to claim 5, characterized in that The bacterial agent is a bacterial agent for promoting plant growth, and the bacterial agent can be used to promote the growth of corn and wheat under saline-alkali stress conditions.

7. The liquid bacterial agent according to claim 6, wherein The bacterial agent includes auxiliary agents; the auxiliary agents include one or more of glycerol, trehalose, sodium benzoate, potassium sorbate, sodium chloride, gamma-polyglutamic acid, sodium dodecylbenzene sulfonate, and chitin.

8. The use of the microbial agent according to claim 7, characterized in that: The bacterial agent promotes the growth of plants under salt stress and / or alkali stress conditions, and the effects of improving plant growth include increasing chlorophyll content, root length, fresh weight and plant height, and is particularly useful in corn and wheat.

9. Use of the bacterial agent according to claim 8 in improving and repairing saline-alkali soil, promoting plant seedling growth, and improving plant tolerance to saline-alkali stress.

Images