Synthetic functional bacterial agent and application thereof in salt tolerance and growth promotion of wheat

Abstract

The invention discloses a synthetic functional bacterial agent and application of the synthetic functional bacterial agent in salt tolerance and growth promotion of wheat, the synthetic functional bacterial agent is prepared from five strains, namely, Gordonia hydrophora, Lysinibacillus oldseyi, planomicrobium okeanokites, Luteimonas huaabiensis and Brevibacterium epidermidis, and the bacterial agent has the remarkable characteristics of no antagonism among the strains, salt and alkali tolerance, high viable count and the like, and can be applied to salt tolerance and growth promotion of wheat. The germination rate, the seedling length and the root length of the spring wheat can be remarkably increased, and the seedling length and the root length of the winter wheat are also remarkably promoted. Under the condition of salt stress, the microbial inoculum can remarkably improve the activity of catalase, peroxidase and superoxide dismutase of wheat and the total content of chlorophyll, after microbial inoculum treatment, the content of malondialdehyde and proline of wheat is remarkably reduced, and the microbial inoculum plays a role in promoting and protecting spring wheat and winter wheat in the process of resisting saline-alkali stress and has a good application prospect. The method has an influence effect on agricultural development and sustainable development in the arid region.

Description

Technical Field

[0001] The invention belongs to the technical field of microorganisms, and specifically relates to a synthetic functional bacterial agent and a preparation method thereof, as well as application in salt-tolerant growth promotion of wheat. Background Art

[0002] Soil salinization affects soil health and environmental quality. It is a major ecological and environmental problem facing dryland agriculture in the world today, which seriously restricts and hinders agricultural development and sustainable development in arid areas. The global area of ​​saline-alkali soil is about 1.1×10 9 hm 2 , about 36 billion hectares of soil in China are salinized to varying degrees, accounting for 4.9% of the country's available arable land (Liu 2023). Xinjiang is known as the world's saline-alkali land museum, with the characteristics of coexistence of salinization and desertification, strong salt accumulation and surface aggregation, and complex soil salt composition. The area of ​​saline-alkali soil in Xinjiang accounts for 9913×10 4 hm 2 ) accounted for 22.01%; in Xinjiang, 407×10 4 hm 2 Among the cultivated land in Xinjiang, the area of ​​cultivated land affected by salinization to varying degrees accounts for 30.12% of the total cultivated land area (Zhang Wanyin et al. 2020). At the same time, Xinjiang is rich in halophytes, among which Chenopodiaceae is the largest family of halophytes in Xinjiang (Wang Lei et al., 2008). As a rare salt-type true halophyte of Chenopodiaceae (Kong Xianwu, 1979), the genus Halotrundae can continuously absorb a large amount of salt ions from the outside world in the salinized habitat, thereby improving the soil properties of saline-alkali land, reducing soil salt content and increasing soil organic matter. However, there are many shortcomings in the single plant remediation method, such as low remediation efficiency, low specificity, and only applicable to medium and low concentrations of environmental stress. Plant-microorganism combined remediation is a more effective remediation method that successfully makes up for these shortcomings.

[0003] In production applications, the practice of improving the plant growth environment and thus increasing crop yields by inoculating beneficial microorganisms has a long history (Baha and Bekki, 2015). However, due to the influence of various environmental factors, the effect of using a single strain is often inhibited, resulting in unstable functional effects. Therefore, the current focus of plant microbial function research has shifted from a single microbial strain to the population level of the microbiome. Synthetic microbial community refers to a microbial community artificially created by co-culturing two or more species under known culture conditions (Großkopf et al., 2014; de Roy et al., 2014). The advantages of synthetic functional bacterial communities over natural microbial communities and single strains are: reducing the complexity of microbial communities, the species in them are known, the composition is relatively simple and the controllability is high, the adaptability to the environment is stronger, and more complex functions can be achieved. More complex system models can be constructed and proved through mathematical models (Biliouris et al., 2012; Jagmann et al., 2014; Martins et al., 2023).

[0004] At present, synthetic functional microbiota has been widely used in agricultural production and biological control. For example, Hu et al. (2016) used 8 strains of Pseudomonas to form a synthetic microbiota to reduce the density of pathogens in the rhizosphere soil of tomatoes. Niu et al. (2017) used 7 bacterial species in corn roots to inhibit the colonization of plant pathogenic fungi. In terms of promoting plant growth, Durán et al. (2018) and Zhuang et al. (2020) screened strains that promote plant growth from the rhizosphere microbial communities of Arabidopsis roots and garlic, respectively. In terms of stress resistance, Castrillo et al. (2017) selected 35 strains from the roots of Arabidopsis and other cruciferous plants to construct a synthetic microbial community, which enhanced the activity of PHR1, the main regulator of phosphate stress response, and promoted the integration of phosphate stress and immunity. Li et al. (2021) constructed a synthetic community composed of 13 bacterial strains to rescue Astragalus root rot by activating plant-induced systemic resistance. Schmitz et al. (2022) used five bacterial strains from the roots of the desert plant Indigofera argentea to construct a synthetic microbial community to protect tomatoes from high salt stress. However, there are few reports on promoting wheat to resist salt stress. Summary of the invention

[0005] In view of the problem that there are few reports on synthetic microbial agents in the prior art to promote wheat to resist salt stress, the present invention provides a synthetic functional microbial agent and a preparation method. The present invention also provides the use of the synthetic functional microbial agent in promoting wheat growth under salt stress conditions. By implementing the technical scheme of the present invention, the germination rate, seedling length and root length of spring wheat can be significantly promoted, and the seedling length and root length of winter wheat can also be significantly promoted. Under salt stress conditions, the microbial agent can significantly promote and protect spring and winter wheat in the process of resisting salt-alkali stress, and has an impact on agricultural development and sustainable development in arid areas.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention provides a synthetic functional bacterial agent, wherein the bacterial agent is prepared from hydrophobic Gordonia ( Gordonia hydrophobic ), Lysinibacillus odysseyii ( Lysinibacillus odysseyi )、Seabed microbes( Planomicrobium okeanokoites )、Xanthomonas sphenanthera( Luteimonas huabeiensis )、Brexibacterium epidermidis( Brevibacterium epidermidis ) and mixed to obtain a resuspension.

[0007] Preferably, the bacterial agent is composed of hydrophobic Gordonia ( Gordonia hydrophobica ), Lysinibacillus odysseyii ( Lysinibacillus odysseyi )、Seabed microbes( Planomicrobium okeanokoites )、Xanthomonas sphenanthera( Luteimonas huabeiensis )、Brexibacterium epidermidis( Brevibacterium epidermidis ) The resuspension was obtained by mixing in a volume ratio of 1:1:1:1:1.

[0008] Preferably, the optical density OD600 of the resuspension of each strain in the bacterial agent is 0.2.

[0009] Preferably, the optical density OD600 of the bacterial agent is 0.02.

[0010] Furthermore, the present invention also provides a method for preparing a synthetic functional bacterial agent, which is prepared by the following steps: inoculating the strain in TSA containing 2% NaCl and culturing to the exponential growth phase, collecting the cells by centrifugation, washing once with 1×PBS, and resuspending in a 10 mM MgCl2 solution; adjusting the optical density OD600 of each cell solution to 0.2; mixing the selected strains at a ratio of 1:1:1:1:1 to obtain a synthetic bacterial agent, and then diluting the bacterial agent to an OD600 of 0.02 for use.

[0011] Furthermore, the present application also provides an application of a synthetic functional bacterial agent in promoting wheat growth under salt stress conditions.

[0012] The application adopts the following steps: wheat seeds are selected, and the surface is sterilized with 3% NaClO solution for 3 times, each time for 1 min, and then washed with sterile water for 3 times; sterile filter paper is pre-laid in a 100 mm×100 mm sterile culture dish and 1.2% NaCl is added to soak the filter paper; the wheat seeds are soaked with a synthetic functional bacterial agent, and after soaking for 8 hours, the seeds are placed in culture dishes containing 1.2% NaCl, with 20 seeds placed in each culture dish, and germinated at room temperature.

[0013] Preferably, a synthetic functional bacterial agent is used to promote wheat growth under salt stress conditions, and wheat seeds of Xinchun No. 26 and Xindong No. 18 are selected.

[0014] Compared with the prior art, the present invention has the following characteristics: (1) The synthetic functional bacterial agent provided by the present invention uses hydrophobic Gordonia ( Gordonia hydrophobica ), Lysinibacillus odysseyii ( Lysinibacillus odysseyi )、Seabed microbes( Planomicrobium oceanokoites )、Xanthomonas sphenanthera( Luteimonas huabeiensis )、Brexibacterium epidermidis( Brevibacterium epidermidis ) Five strains of bacteria, the bacterial agent has the remarkable characteristics of no antagonism between strains, salt and alkali resistance, and high number of viable bacteria.

[0015] (2) The synthetic functional bacterial agent provided by the present invention can significantly promote the germination rate, seedling length and root length of spring wheat by soaking wheat seeds, and also has a significant promoting effect on the seedling length and root length of winter wheat.

[0016] (3) The synthetic functional bacterial agent provided by the present invention can significantly increase the activities of catalase, peroxidase, superoxide dismutase and the total chlorophyll content of wheat under salt stress conditions. After treatment with the bacterial agent, the contents of malondialdehyde and proline in wheat are significantly reduced. The bacterial agent plays a promoting and protective role in the process of spring wheat and winter wheat resisting salt-alkali stress, and has an impact on agricultural development and sustainable development in arid areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The colony morphology observation results of five strains.

[0018] Figure 2 The effect of synthetic bacterial agents on the morphology of hydroponic wheat plants.

[0019] Figure A shows the observation picture of the hydroponic plant morphology of spring wheat; Figure B shows the observation picture of the hydroponic plant morphology of winter wheat.

[0020] Figure 3 Shown is the effect of synthetic bacterial agents on wheat germination rate, seedling length and root length.

[0021] Figure A shows the changes in the germination rate of spring wheat; Figure B shows the changes in the germination rate of winter wheat; Figure C shows the changes in the length of spring wheat seedlings; Figure D shows the changes in the length of winter wheat seedlings; Figure E shows the changes in the root length of spring wheat; and Figure F shows the changes in the root length of winter wheat.

[0022] Figure 4 Shown is the effect of synthetic bacterial agents on the activity of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), and total chlorophyll content, malondialdehyde (MDA) content, and proline (PRO) content of wheat.

[0023] Figure A shows the changes in catalase (CAT) activity of spring wheat; Figure B shows the changes in catalase (CAT) activity of winter wheat; Figure C shows the changes in superoxide dismutase (SOD) activity of spring wheat; Figure D shows the changes in superoxide dismutase (SOD) activity of winter wheat; Figure E shows the changes in peroxidase (POD) activity of spring wheat; Figure F shows the changes in peroxidase (POD) activity of winter wheat; Figure G shows the changes in chlorophyll content of spring wheat; Figure H shows the changes in chlorophyll content of winter wheat; Figure I shows the changes in malondialdehyde (MDA) content of spring wheat; Figure J shows the changes in malondialdehyde (MDA) content of winter wheat; Figure K shows the changes in proline (PRO) content of spring wheat; Figure L shows the changes in proline (PRO) content of winter wheat. DETAILED DESCRIPTION

[0024] The following examples are used to further illustrate the content of the present invention, but should not be construed as limiting the present invention. Without departing from the spirit and essence of the present invention, modifications or substitutions made to the method, steps or conditions of the present invention all belong to the scope of the present invention.

[0025] The hydrophobic Gordonia used in the present invention ( Gordonia hydrophobica ), Lysinibacillus odysseyii ( Lysinibacillus odysseyi )、Seabed microbes( Planomicrobium okeanokoites )、Xanthomonas sphenanthera( Luteimonas huabeiensis )、Brexibacterium epidermidis( Brevibacterium epidermidis ) All five strains were harmless and safe, among which the hydrophobic Gordonia ( Gordonia hydrophobica ), Lysinibacillus odysseyii ( Lysinibacillus odysseyi )、Brexibacterium epidermidis( Brevibacterium epidermidis ) can be purchased through other public channels such as the China General Microorganism Collection Center (CGMCC), and seabed microbes ( Planomicrobium oceanokoites ) can be purchased through other public channels such as the Weihai Marine Microbial Resources Center of Shandong University, and Xanthomonas sphaeroides ( Luteimonas huabeiensis) can be purchased through other public channels such as Beijing Biobowei Biotechnology Co., Ltd.

[0026] In this application, the following examples refer to “hydrophobic Gordonia ( Gordonia hydrophobica )" are all abbreviated as "hydrophobic Gordonia"; "Odyssey Lysinibacillus ( Lysinibacillus odysseyi )" are all abbreviated as "Odyssey Lysin Bacillus"; "Seabed Motile Microbes ( Planomicrobium okeanokoites )" are all abbreviated as "seabed mobile microbes"; "Yellow Mononas sphenanthera ( Luteimonas huabeiensis )" are abbreviated as "Yellow Mononas huabei", "Breibacillus epidermidis ( Brevibacterium epidermidis )" are abbreviated as "Brexibacillus epidermidis".

[0027] The New Spring No. 26 and New Winter No. 18 wheat seeds used in this application were donated by the Institute of Nuclear Technology and Biotechnology of the Xinjiang Academy of Agricultural Sciences. The general public can purchase them through the Institute of Nuclear Technology and Biotechnology of the Xinjiang Academy of Agricultural Sciences or seed companies.

[0028] The broth soy peptone agar medium TSA used in this application is a conventional culture medium in the art.

[0029] The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, etc. used in the following examples are all commercially available unless otherwise specified.

[0030] Example 1: A synthetic functional bacterial agent The invention provides a synthetic functional bacterial agent, which is obtained by mixing a heavy suspension of hydrophobic Gordonia hydrophobica, lysine Bacillus odyssey, seabed motile microbes, Xanthomonas sphaeroides, and Brevibacterium epidermidis.

[0031] The hydrophobic Gordonia used Gordonia hydrophobica ), Lysinibacillus odysseyii ( Lysinibacillus odysseyi )、Seabed microbes( Planomicrobium okeanokoites )、Xanthomonas sphenanthera( Luteimonas huabeiensis )、Brexibacterium epidermidis( Brevibacterium epidermidis ) For colony morphology, see Appendix Figure 1 shown.

[0032] The present invention also provides a method for preparing a synthetic functional bacterial agent, which is specifically prepared by the following steps: inoculating the strain in TSA containing 2% NaCl and culturing to the exponential growth phase, collecting the cells by centrifugation, washing once with 1×PBS, and resuspending in a 10 mM MgCl2 solution; adjusting the optical density OD600 of each cell solution to 0.2; mixing the selected strains at a ratio of 1:1:1:1:1 to obtain a synthetic bacterial agent, and then diluting the bacterial agent to an OD600 of 0.02 for standby use.

[0033] Furthermore, the present application also provides an application of a synthetic functional bacterial agent in promoting wheat growth under salt stress conditions, and the application adopts the following steps: selecting wheat seeds, surface sterilizing them with 3% NaClO solution for 3 times, each time for 1 min, and then washing them with sterile water for 3 times; pre-laying sterile filter paper in a 100 mm×100 mm sterile culture dish and adding 1.2% NaCl to soak the filter paper; soaking the wheat seeds with the synthetic functional bacterial agent, after soaking for 8 hours, placing the seeds in culture dishes containing 1.2% NaCl, placing 20 seeds in each culture dish, and germinating them at room temperature.

[0034] Example 2: Hemolytic detection The hydrophobic Gordonia, Lysinibacillus odyssey, Seabed Motile Microbacteria, Yellow Mononas spp., and Brevibacterium epidermidis strains were inoculated on a hemolytic medium and cultured at 30°C for 3-7 days. A 1-2 mm translucent hemolytic ring was observed around the colony, indicating that the strain was hemolytic. The test results showed that the selected hydrophobic Gordonia, Lysinibacillus odyssey, Seabed Motile Microbacteria, Yellow Mononas spp., and Brevibacterium epidermidis did not have a hemolytic reaction, indicating that the selected five strains are biosafety strains and can be used for the construction of synthetic bacterial agents in the future.

[0035] Example 3: Strain antagonism experiment For the obtained Gordonia hydrophobica, Lysine Bacillus odyssey, Seabed Motile Microbacteria, Yellow Mononas huabei, and Brevibacterium epidermidis, the selected strains were subjected to pairwise antagonism experiments, one strain was selected for liquid culture, and the other strains were cultured on solid culture. The cultured bacterial solution was evenly spread on the solid culture medium, the colony of the solid culture strain was punched with a hole puncher, and the colony agar block was clamped with tweezers and turned upside down on the plate coated with indicator bacteria; the plate was covered and cultured in an incubator, and the transparent inhibition zone was observed around the agar block, and the diameter of the inhibition zone was measured. The determination showed that no transparent inhibition zone was formed between the selected strains, indicating that there was no antagonistic reaction between the selected strains, and they could be used for the construction of synthetic bacterial agents in the future.

[0036] Example 4: Construction of synthetic functional bacterial agent Based on the records in the above examples to Example 3, strains that tolerate 5% NaCl, have no hemolytic activity, and have no antagonistic effects on each other were selected from the above results. The strains were inoculated in TSA containing 2% NaCl and cultured until the exponential growth phase. The cells were collected by centrifugation, washed once with 1× PBS, and resuspended in 10 mM MgCl2 solution. The optical density (OD) of each cell solution was calculated. 600 ) was adjusted to 0.2. The selected strains were mixed at a ratio of 1:1:1:1:1 to obtain a synthetic bacterial agent, and then the bacterial agent was diluted to an OD600 0.02 is reserved.

[0037] Example 5: Synthetic bacterial agent promotes wheat growth Based on the synthetic functional bacterial agents obtained according to the records of the above-mentioned Example 4, the wheat seeds of New Spring No. 26 and New Winter No. 18, which are commonly planted in Xinjiang, were selected and surface sterilized three times with 3% NaClO solution for 1 min each time, and then washed three times with sterile water. The experimental group used a mixed culture of synthetic bacteria to soak the wheat seeds, and the control group used sterile water to soak the seeds; sterile filter paper was pre-laid in a 100 mm × 100 mm sterile culture dish and 1.2% NaCl was added to soak the filter paper. After soaking for 8 hours, the seeds were placed in culture dishes containing 1.2% NaCl, with 20 seeds placed in each culture dish, and germinated at room temperature. About 10 days later, when the third true leaf appeared on the seedlings, growth indicators such as seed germination rate, root length and seedling length were measured to preliminarily evaluate the growth situation. In this experiment, 3 technical replicates and 3 biological replicates were set for each treatment. The observation and determination results of the hydroponic plant morphology of spring wheat and winter wheat in the determination results are shown in the attached Figure 2 As shown in the figure, the growth of spring wheat and winter wheat in the CM group treated with synthetic microorganisms was significantly better than that in the CK+NaCl group and CK+H2O group treated with salt stress. The germination rate, seedling length and root length of spring wheat and winter wheat were measured, see Appendix Figure 3 The results showed that under salt stress conditions, the mixed bacterial agent significantly promoted the germination rate, seedling length and root length of spring wheat. It also had a significant promoting effect on the seedling length and root length of winter wheat.

[0038] Example 6: Detection of Synthetic Bacterial Agents Promoting Enzyme Activity in Wheat Plants Based on the treatment of the synthetic bacterial agent in the above Example 5, wheat leaves were taken after 10 days and stored in a liquid nitrogen tank. The plant enzyme activity was detected using the BCA protein content assay kit, catalase (CAT) kit, superoxide dismutase (SOD) kit, peroxidase (POD) kit, malondialdehyde (MDA) content kit, proline (PRO) content assay kit and plant chlorophyll (chlorophyll) content kit of Suzhou Keming Biotechnology Co., Ltd.

[0039] The results of plant enzyme activity on hydroponic wheat are shown in the attached Figure 4As shown in, under salt stress conditions, the bacterial agent can significantly increase the activities of wheat catalase (CAT), peroxidase (POD), superoxide dismutase (SOD) and total chlorophyll content. At the same time, after treatment with the bacterial agent, the contents of malondialdehyde (MDA) and proline (PRO) in wheat are significantly reduced, indicating that the bacterial agent plays a promoting and protective role in the process of spring wheat and winter wheat resisting salt-alkali stress.

[0040] Comparative Example 1: Comparison of growth-promoting effects of different strains and combinations Based on the synthetic functional bacterial agent constructed in Example 4, the five selected strains were compounded in a single strain and two-by-two combination in a ratio of 1:1, and a wheat germination experiment was performed for comparison. The wheat seeds of New Spring No. 26 and New Winter No. 18, which are commonly planted in Xinjiang, were selected and surface sterilized 3 times with 3% NaClO solution, each time for 1 min, and then washed 3 times with sterile water. The wheat seeds were soaked in a mixed culture of synthetic bacteria, and sterile filter paper was pre-laid in a 100 mm × 100 mm sterile culture dish and 1.2% NaCl was added to soak the filter paper. After soaking for 8 hours, the seeds were placed in culture dishes containing 1.2% NaCl, 20 seeds were placed in each culture dish, and germinated at room temperature, with three replicates for each group. About 10 days later, the seed germination rate was measured when the third true leaf appeared on the seedling. The grouping treatment and wheat germination rate are shown in Table 1 below.

[0041] Table 1: Grouping treatment and wheat germination rate

[0042] By comparing the growth-promoting effects of the above-mentioned different strains and combinations, it can be seen that the growth-promoting effect of a single strain on spring wheat and winter wheat is lower than the growth-promoting effect obtained by combining the selected strains in pairs. The synthetic functional bacterial agent composed of the five strains selected in this application has the best effect on promoting the growth of spring wheat and winter wheat under saline-alkali stress, and the germination rate of spring wheat and winter wheat is significantly higher than that of other comparative treatment groups. It also confirms that the combination of five strains selected in the technical scheme provided in this application can exert an excellent synergistic effect, which has a significant impact on agricultural development and sustainable development in arid areas.

[0043] The above embodiments are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A synthetic functional bacterial agent, characterized in that: The bacterial agent is composed of hydrophobic Gordonia ( Gordonia hydrophobic ), Lysinibacillus odysseyii ( Lysinibacillus odysseyi )、Seabed microbes( Planomicrobium okeanokoites )、Xanthomonas sphenanthera( Luteimonas huabeiensis )、Brexibacterium epidermidis( Brevibacterium epidermidis ) and mixed to obtain a resuspension.

2. A synthetic functional bacterial agent according to claim 1, characterized in that: The bacterial agent is composed of hydrophobic Gordonia ( Gordonia hydrophobica ), Lysinibacillus odysseyii ( Lysinibacillus odysseyi )、Seabed microbes( Planomicrobium okeanokoites )、Xanthomonas sphenanthera( Luteimonas huabeiensis )、Brexibacterium epidermidis( Brevibacterium epidermidis ) The resuspension was obtained by mixing in a volume ratio of 1:1:1:1:

1.

3. A synthetic functional bacterial agent according to claim 1, characterized in that: The optical density OD600 of the resuspension of each strain in the bacterial agent is 0.

2.

4. A synthetic functional bacterial agent according to claim 1, characterized in that: The optical density OD600 of the bacterial agent is 0.

02.

5. The method for preparing a synthetic functional bacterial agent according to claim 1, characterized in that: The preparation was specifically carried out using the following steps: the strain was inoculated in TSA containing 2% NaCl and cultured to the exponential growth phase, the cells were collected by centrifugation, washed once with 1×PBS, and resuspended in 10 mM MgCl2 solution; the optical density OD600 of each cell solution was adjusted to 0.2; the selected strains were mixed at a ratio of 1:1:1:1:1 to obtain a synthetic bacterial agent, and then the bacterial agent was diluted to OD600 of 0.02 for use.

6. Use of a synthetic functional bacterial agent as claimed in any one of claims 1 to 5 in promoting wheat growth under salt stress conditions.

7. The use of a synthetic functional bacterial agent as claimed in claim 6 in promoting wheat growth under salt stress conditions, characterized in that: The application uses the following steps: Wheat seeds were selected and surface sterilized with 3% NaClO solution for 3 times, each time for 1 min, and then washed with sterile water for 3 times; sterile filter paper was pre-laid in a 100 mm×100 mm sterile culture dish and 1.2% NaCl was added to soak the filter paper; the wheat seeds were soaked with a synthetic functional bacterial agent. After soaking for 8 hours, the seeds were placed in culture dishes containing 1.2% NaCl, with 20 seeds placed in each culture dish, and germinated at room temperature.

8. The use of a synthetic functional bacterial agent as claimed in claim 6 in promoting wheat growth under salt stress conditions, characterized in that: Choose wheat seeds No. 26 for the new spring and No. 18 for the new winter.

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