Glutamicobacterium halogenes for improving salt tolerance of crops and application of glutamicobacterium halogenes

Abstract

The invention belongs to the technical field of microorganism application, and particularly relates to glutamicobacterium halogenes capable of improving the salt tolerance of crops and application of the glutamicobacterium halogenes, the glutamicobacterium halogenes are Glutamicobacterium halogenes G37-2, the preservation number is CCTCC NO: M 20242581, and the glutamicobacterium halogenes are preserved in the China Center for Type Culture Collection on November 18, 2024. The glutamicobacter halophila G37-2 disclosed by the invention has the growth promoting characteristics of producing auxin and forming a biological membrane, and also can be used for remarkably promoting seedling emergence and seedling growth of soybeans under salt stress, and promoting germination of rape seeds and growth of radicles and buds. Furthermore, the glutamicobacterium halogenes can obviously improve the emergence rate of soybeans, increase the area of functional leaves of the soybeans, promote the growth of seedlings and relieve the inhibition effect of salt stress on emergence and growth of the seedlings of the soybeans, so that the adaptive capacity of the soybeans to the salt stress is enhanced; the germination of rape seeds can be promoted, and the inhibition effect of salt stress on the growth of rape embryonic root systems and buds is relieved.

Description

Technical Field

[0001] The invention belongs to the technical field of microbial application, and particularly relates to a haloglutamate bacillus capable of improving the salt tolerance of crops and an application thereof. Background Art

[0002] China ranks third in the world in terms of saline-alkali land area, covering approximately 1.5 billion mu (approximately 1.5 billion hectares), of which 500 million mu (approximately 1.5 billion hectares) has potential for development and utilization, accounting for over 10% of China's total arable land. Effective development of saline-alkali land is crucial for alleviating the imbalance between land supply and population and ensuring food security. In recent years, growing salt-tolerant crops on saline-alkali land has become an important means of effectively utilizing this land.

[0003] Soybeans and rapeseed are field crops that are particularly well-suited for saline-alkali soils. Soybeans are not only an important source of high-quality protein in the local diet, but are also moderately salt-tolerant, capable of growing in mildly to moderately saline-alkali soils, expanding their cultivation range. As a legume, soybeans can symbiotically fix nitrogen with rhizobia, enhancing soil fertility, improving the nutrient status of saline-alkali soils, and reducing reliance on chemical fertilizers. Rapeseed is an important oilseed crop and a major wintering crop in many provinces. Rapeseed also exhibits a degree of salt-alkali tolerance, absorbing water and nutrients from deep soil layers through its deep root system, further enhancing its adaptability to saline-alkali soils. Rapeseed flowers also offer ornamental value. Therefore, cultivating soybeans and rapeseed in saline-alkali soils offers unique advantages for utilizing and improving saline-alkali soils, potentially generating both economic and ecological benefits, and holds broad prospects.

[0004] However, high concentrations of salt-based ions in the soil can cause osmotic stress, oxidative stress, ion poisoning, etc. to plants, seriously affecting plant growth. Existing technologies have found that the key traits of soybeans grown in saline-alkali soils are significantly reduced, including a 25% decrease in plant height, a 26.6% decrease in the number of pods, a 33% decrease in seed yield, and a 13% decrease in 100-grain weight. The salt stress caused by NaCl causes soybean yield to drop by up to 40%, or even complete failure. The seed germination and seedling stage are critical periods for plant growth and are also the stages most sensitive to saline-alkali stress. In saline-alkali soils, there are common prominent problems such as difficulty in seed emergence after sowing, dead seedlings after emergence, and weak growth, which have a serious adverse effect on yield formation. Therefore, there is an urgent need to provide a new strategy that can significantly alleviate the stress of salt on crop growth. Summary of the Invention

[0005] The purpose of the present invention is to provide a haloglutamate bacillus that improves the salt tolerance of crops, so as to alleviate the influence of salt stress on the growth of crops.

[0006] The technical solution adopted in the present invention is:

[0007] The present invention provides a glutamic acid bacillus halophytocola for improving the salt tolerance of crops. The glutamic acid bacillus halophytocola is Glutamicibacter halophytocola G37-2, with a preservation number of CCTCC NO: M 20242581, and was deposited in the China Center for Type Culture Collection on November 18, 2024.

[0008] A second aspect of the present invention provides a bacterial suspension, which is obtained by culturing the halogenated glutamicum bacteria, wherein the culturing process is as follows:

[0009] Inoculate glutamicum salinarum into LB medium, culture at 28℃~30℃, 180rpm for 16h~18h, collect bacteria, and adjust the viable bacteria count of glutamicum salinarum to 10 with sterile water. 9 CFU / mL, and the bacterial suspension is obtained.

[0010] Preferably, the culturing process is as follows:

[0011] Inoculate glutamicum salinarum into LB medium and culture at 28°C and 180 rpm for 17 h. Collect the cells and adjust the viable count of glutamicum salinarum to 10 with sterile water. 9 CFU / mL, and the bacterial suspension is obtained.

[0012] The third aspect of the present invention provides the use of the halogenated glutamicum bacteria or the bacterial suspension, characterized in that the use refers to any one of the following:

[0013] 1) Promote crop emergence;

[0014] 2) Promote the growth of crops in seedling stage;

[0015] 3) Promote crop seed germination;

[0016] 4) Improve crop salt tolerance.

[0017] Preferably, the crop includes any one of soybean and rapeseed.

[0018] The fourth aspect of the present invention provides a microbial growth promoter, which comprises the halogenated glutamicum bacillus, and the number of viable bacteria of the halogenated glutamicum bacillus in the microbial growth promoter is 10 9 CFU / mL.

[0019] The fifth aspect of the present invention provides a microbial germination promoter, characterized in that the microbial germination promoter comprises the halogenated glutamicum bacillus, and the number of viable bacteria of the halogenated glutamicum bacillus in the microbial germination promoter is 10 9 CFU / mL.

[0020] Preferably, the microbial growth promoter or microbial germination promoter further comprises a microbiologically acceptable auxiliary material.

[0021] Preferably, the microbiologically acceptable excipients include at least one of a filler, a binder, a disintegrant, a lubricant and an antacid.

[0022] Preferably, the filler includes any one of sodium alginate, polyacrylamide and zeolite.

[0023] Preferably, the binder comprises any one of starch slurry, hydroxypropyl methylcellulose and povidone.

[0024] Preferably, the disintegrant includes any one of starch, microcrystalline cellulose and low-substituted hydroxypropyl cellulose.

[0025] Preferably, the lubricant comprises any one of a microalgae-based biolubricant, mucin and tannic acid.

[0026] Preferably, the antacid comprises any one of phosphate buffer, bicarbonate buffer and Tris buffer.

[0027] Preferably, the application method of the microbial growth promoter or microbial bud promoter includes any one of root irrigation and seed soaking.

[0028] The biomaterial sample preservation information involved in the present invention is as follows:

[0029] Glutamicibacter halophytocola G37-2 was deposited with the China Center for Type Culture Collection on November 18, 2024. The proposed taxonomic name is Glutamicibacter halophytocola G37-2, and the deposit number is CCTCC NO: M 20242581. The deposit address is Wuhan University, No. 299, Bayi Road, Wuchang District, Wuhan City, Hubei Province. For the convenience of description in this invention, Glutamicibacter halophytocola G37-2 is referred to as G37-2.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The present invention provides a salt-tolerant glutamic acid bacillus for improving the salt tolerance of crops. The salt-tolerant glutamic acid bacillus is Glutamicibacter halophytocola G37-2, with a deposit number of CCTCC NO: M20242581, and was deposited in the China Center for Type Culture Collection on November 18, 2024. The present invention isolated for the first time a salt-tolerant glutamic acid bacillus Glutamicibacter halophytocola G37-2 with salt-tolerant growth-promoting function from the root system of Salicornia herbacea in the coastal saline-alkali land of Jiangsu. The bacterium has the growth-promoting properties of producing IAA and biofilm, which can significantly promote the emergence and growth of soybean seedlings under salt stress, and promote the germination of rapeseed seeds, and the growth of radicles and buds. The microbial germination and growth promoters further prepared using this Glutamicibacter halophytocola G37-2 can significantly improve the soybean emergence rate, increase the functional leaf area of ​​soybeans, promote seedling growth, alleviate the inhibitory effects of salt on soybean seed germination and root growth, and thus enhance the soybean's adaptability to salt stress; they can also promote rapeseed seed germination and alleviate the inhibitory effects of salt stress on the rapeseed embryonic root system and bud growth. Therefore, the Glutamicibacter halophytocola G37-2 and the microbial germination and growth promoters containing G37-2 show broad application prospects in promoting seed germination, emergence, and growth of crops such as soybeans and rapeseed in saline-alkali farmland. This provides important resource and technical support for the development of microbial agents or fertilizers suitable for saline-alkali land, and also lays a material and technical foundation for creating significant ecological and economic benefits.

[0032] The present invention also discloses the use of the halobacterium glutamicum in promoting soybean seedling emergence under salt stress. Soil pot experiments show that under salt stress with a NaCl concentration of 1.5‰, the inoculation of strain G37-2 doubles the seedling emergence rate compared to the uninoculated control.

[0033] In addition, the present invention also discloses the application of the haloglutamicum in promoting soybean growth under salt stress. The soil pot experiment showed that when 1.5‰ NaCl was added to the soil to simulate salt stress, the soybean seeds were immersed in OD 600 The G37-2 suspension was diluted to 1.0 to achieve seed inoculation. The G37-2 suspension was inoculated into the soil before soybean sowing. Seven days after soybean sowing, the soybean roots were again irrigated with an OD of 1.0. 600 The G37-2 bacterial suspension with a value of 1.0 was cultured for 25 days. The G37-2 strain was able to significantly alleviate the inhibitory effect of NaCl stress on soybean growth, restoring indicators such as plant height, aboveground fresh weight, upper third leaf area, and root fresh weight to levels close to or exceeding those of the control without NaCl.

[0034] The present invention also discloses the use of the G37-2 bacterium in promoting rapeseed germination under salt stress. Inoculation with the G37-2 strain completely eliminated the inhibitory effect of NaCl stress on rapeseed germination. Under 150 mM NaCl stress, inoculation with 10% G37-2 bacterial solution increased radicle length and shoot length by 2.19 times and 1.03 times, respectively, compared to the uninoculated control. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a photo of the colony morphology of Salinobacterium Glutamycin G37-2 on LB solid medium.

[0036] Figure 2 This is the phylogenetic tree of the 16S rRNA gene of Salinobacterium glutamicum G37-2.

[0037] Figure 3 These are diagrams showing the effect of Halobacterium glutamicum G37-2 on promoting soybean emergence under 1.5‰ NaCl stress, A: growth status 5 days after sowing; B: growth status 9 days after sowing.

[0038] Figure 4 Soybean emergence rate under original soil, 1.5‰ NaCl stress, 1.5‰ NaCl stress and G37-2 inoculation treatment.

[0039] Figure 5 This is a diagram showing the effect of Halobacterium glutamicum G37-2 on promoting soybean seedling growth under 1.5‰ NaCl stress, A: 4 parallel samples of the CK group; B: 4 parallel samples of the NaCl group; C: 4 parallel samples of the NaCl+G37-2 group.

[0040] Figure 6 The soybean plant heights under original soil, 1.5‰ NaCl stress, and 1.5‰ NaCl stress and G37-2 inoculation treatments, A: soybean plant height after 11 days of cultivation; B: soybean plant height after 25 days of cultivation.

[0041] Figure 7 These are the growth indicators under original soil, 1.5‰ NaCl stress, and 1.5‰ NaCl stress and inoculation with G37-2. A: soybean aboveground fresh weight; B: root fresh weight; C: inverted third leaf area.

[0042] Figure 8 This is a diagram showing the effect of G37-2 on promoting rapeseed seed germination under salt stress. A to E are the results of H2O, 150NaCl, 150NaCl+1%G37-2, 150NaCl+10%G37-2, and 150NaCl+50%G37-2, respectively. The three rows represent three parallel experiments in the corresponding groups. DETAILED DESCRIPTION

[0043] The present invention will be further described below by way of specific examples, but the scope of the present invention is not limited thereto. The details and forms of the technical solution of the present invention may be modified or replaced without departing from the spirit and scope of the present invention, but such modifications or replacements fall within the scope of protection of the present invention.

[0044] The inventive concept of the present invention is as follows:

[0045] Plants and microorganisms have undergone hundreds of millions of years of co-evolution to form a close symbiotic functional body. Root-associated microorganisms have evolved a variety of mechanisms to improve the host's salt tolerance, playing an important and irreplaceable role in alleviating the damage of salt stress to plants. Some plant growth-promoting bacteria can promote plant growth by producing auxins, or reduce the level of harmful ethylene in plants by secreting ACC deaminase, thereby alleviating the negative effects of salt stress on plants. In addition, they can also reduce the damage of salt stress to plants by producing siderophores, secreting extracellular polysaccharides, etc. Currently, the most widely used salt-tolerant plant growth-promoting bacteria are mainly concentrated in the genera Bacillus and Pseudomonas. Regarding Glutamicibacter halophytocola, Chinese patent CN202210024727.8 discloses the application of Glutamicibacter halophytocola G2 in organic waste composting, biogas slurry, eutrophic water bodies, and black and odorous water treatment; Chinese patent CN202411073717.9 discloses the application of Glutamicibacter halophytocola DL1 in carbon fixation. However, there are currently no reports on the growth-promoting effect of Glutamicibacter halophytocola on crops such as soybeans and rapeseed under salt stress, and on its improvement of their adaptability to salt stress.

[0046] The purpose of the present invention is to provide a halotrophic glutamicum strain that can promote the growth of soybeans and rapeseed under salt stress, and by using the bacteria to improve the soybean emergence rate, promote the growth of soybeans in the seedling stage, and alleviate the inhibition of salt on rapeseed germination and root growth, thereby enhancing the tolerance of the two crops to salt stress.

[0047] In order to make those skilled in the art better understand the technical solution of the present invention and be able to implement it, the present invention is further described below in conjunction with specific examples. In the description of the present invention, if not otherwise specified, the reagents used are all commercially available and the methods used are all conventional techniques in the art.

[0048] The preparation method of the reagents used in the present invention is as follows:

[0049] Each liter of LB medium contains: 10 g of tryptone, 5 g of yeast extract, 10 g of sodium chloride, 1000 mL of distilled water, and a pH value of 7.0, which is a liquid medium. 20 g of agar powder is added to the liquid medium to form a solid medium, and sterilized at 121°C for 20 minutes.

[0050] Salkowski colorimetric solution: Mix 1 part 0.5 mol / LFeCl3 and 49 parts 35% by volume HClO4 according to the volume ratio and store in the dark.

[0051] 0.1% by mass crystal violet staining solution: Weigh 0.1 g of crystal violet, add it to 10 mL of anhydrous ethanol, stir thoroughly until completely dissolved, add water to make up to 100 mL, mix well, and set aside.

[0052] PBS buffer: Weigh 8 g of sodium chloride, 0.2 g of potassium chloride, 3.63 g of disodium hydrogen phosphate, and 0.24 g of potassium dihydrogen phosphate, dissolve in 900 mL of distilled water, add water to make up to 1000 mL, and store at room temperature until used.

[0053] Example 1

[0054] A haloglutamate bacillus capable of improving the salt tolerance of crops, specifically as follows:

[0055] 1. Isolation, identification and growth-promoting properties of strain G37-2.

[0056] Strain G37-2 was isolated and screened from the root system of Salicornia herbacea in the saline-alkali land of Binhai, Jiangsu. On June 15, 2022, the present invention collected three healthy Salicornia herbacea plants from a severely saline-alkali land in Binhai, Jiangsu, and brought them back to the laboratory in sterile bags. Carefully cut the roots of the plant with scissors, wash the roots with tap water, remove the soil attached to the surface, and then rinse with sterile water three times. After disinfecting with 75% ethanol by volume for 5 minutes, wash once with sterile water, and then disinfect with 2.5% sodium hypochlorite by volume for 5 minutes, and wash three times with sterile water to disinfect the surface of the root system. 100 μL of water after the last elution was absorbed and spread on an LB solid plate. After culturing for 5 days, no colonies grew on the plate, indicating that the disinfection was thorough. Use sterilized scissors to cut about 1.5 g of root tissue, place it in a sterile mortar, add 1.5 mL of sterile water, and grind until a homogenate is formed. 100 μL of homogenate was taken from each sample and evenly spread on an LB plate, which was then cultured in a 28°C incubator for 4 days. After the culture was completed, colonies with different morphology and color were picked, purified, numbered, and stored.

[0057] The purified strain was tested for its indole-3-acetic acid (IAA) production and biofilm formation characteristics.

[0058] The IAA assay is as follows: the purified strain is inoculated into LB liquid medium containing 100 mg / L L-tryptophan and cultured with shaking at 28°C and 180 rpm for 48 hours. After the culture is complete, 100 μL of the bacterial culture is mixed with 100 μL of Salkowski colorimetric solution and added to a 96-well plate. A blank control is also set up, consisting of 100 μL of uninoculated culture mixed with 100 μL of Salkowski colorimetric solution. The 96-well plate is placed in the dark for 30 minutes, and then the color of the mixture is observed in a bright environment. If the strain produces IAA, the mixture will appear pink, and a darker pink color indicates a higher IAA production capacity.

[0059] The biofilm formation ability of the strain was determined as follows: the strain was inoculated into LB liquid medium and cultured at 28°C and 180 rpm for 17 h. The bacterial solution was diluted with LB medium at a volume ratio of 1:100. At this time, the OD 600 ≈0.1. Add 200 μL of the diluted bacterial solution to a 96-well culture plate and incubate at 28°C for 24 hours. Wash away unattached bacteria with PBS buffer. Stain adherent cells with 100 μL of 0.1% crystal violet for 30 minutes. Rinse with PBS buffer to remove any excess color. After air-drying, add 200 μL of 95% ethanol by volume. Once the crystal violet is completely dissolved, measure the absorbance at 595 nm and record it as As. Use LB medium as a control and record it as Ac. Assess bacterial biofilm formation ability: an As / Ac ratio < 1 indicates no biofilm formation; an As / Ac ratio > 1 indicates biofilm formation.

[0060] Based on the strain's ability to produce IAA and biofilm, a strain was selected. After 48 hours of culture, the strain produced 13.8 μg / mL of IAA and had a biofilm production As / Ac ratio of 1.77 after 24 hours of culture. The strain was named G37-2. Its colony morphology on LB solid medium is as follows: Figure 1 shown.

[0061] The G37-2 strain was cultured in LB liquid medium. A small amount of fresh G37-2 cells was dipped into the PCR reaction system with a sterile toothpick. The 16S rRNA gene was amplified by PCR using universal primers 27F and 1492R. The PCR product was then sent to Beijing Liuhe BGI Genomics Co., Ltd. for sequencing. The sequencing result of the PCR product is shown in SEQ ID NO.3. The obtained 16S rRNA gene sequence was uploaded to EzBioCloud for homology comparison. The strain sequences with high similarity to the sequence of G37-2 were downloaded, and the phylogenetic tree was constructed using MEGA 5.0. The results are shown in Figure 3. Figure 2As shown, the 16S rRNA gene sequence of the strain was clustered on the same branch as that of Glutamicibacter halophytocola KLBMP 5180 (Type), and the sequence similarity of the strain was 100%. The strain was identified as Glutamicibacter halophytocola.

[0062] The primer sequences of 27F and 1492R are shown in SEQ ID NO.1 and SEQ ID NO.2.

[0063] 27F, SEQ ID NO. 1: 5'-AGAGTTTGATCMTGGCTCAG-3'.

[0064] 1492R, SEQ ID NO. 2: 5'-TACGGYTACCTTGTTACGACTT-3'.

[0065] The website of EzBioCloud is https: / / www.ezbiocloud.net / .

[0066] >G37-2, SEQ ID NO. 3:

[0067]

[0068] Example 2

[0069] An application of halobacterium glutamicum for improving the salt tolerance of crops is as follows:

[0070] 1. Strain G37-2 promotes soybean emergence under salt stress.

[0071] Test soil: Soil from the 0 cm to 20 cm farmland topsoil of Xinyang Experimental Station, Yancheng City, Jiangsu Coastal Agricultural Research Institute, Jiangsu Academy of Agricultural Sciences, was collected. The soluble salt content of the soil was 0.5‰.

[0072] Potted plant setup: Based on dry soil, weigh 150g of test soil into a culture cup. Set up three treatments: ①NaCl treatment, that is, add 1.5‰NaCl to the test soil; ②NaCl+G37-2 treatment, that is, add 1.5‰NaCl to the test soil and inoculate strain G37-2; ③Control treatment CK, that is, no NaCl is added to the test soil and no bacteria are inoculated. The NaCl+G37-2 treatment is specifically as follows: inoculate strain G37-2 into LB liquid culture medium, shake and culture at 28℃ and 180rpm for 17h, collect the bacteria by centrifugation, and adjust the bacteria to OD with sterile water. 600 =1, the number of viable bacteria is about 10 9 CFU / mL, and obtain a bacterial suspension. This bacterial suspension was inoculated into the soil to make the inoculation concentration of the bacteria in the soil 10 9 CFU / g soil. Soybean seeds were disinfected with 75% alcohol by volume for 1 minute, washed once with sterile water, and then disinfected with 2.5% NaClO by volume for 2 minutes, washed three times with sterile water, and the last wash water was used to spread on a plate and cultured for 5 days to confirm that no bacteria grew, indicating that the disinfection was complete. The disinfected soybean seeds were immersed in OD 600 = 1 bacterial suspension for 2 minutes, stirring thoroughly to allow the bacteria to evenly adhere to the seed surface. After the soybean leaves have unfolded, inoculate the strain again to enhance the colonization effect of the strain.

[0073] Sowing and cultivation of soybeans in the three treatments: 5 soybean seeds were sown in each culture cup. The culture cups were placed in a glass greenhouse with a daytime temperature of 28°C and a nighttime temperature of 22°C. Water was added regularly to maintain the soil moisture content at 60% of the soil's maximum water holding capacity. After the single leaf expanded after 7 days of cultivation, the seedling emergence rate was calculated. Thinning was performed, with 2 seedlings per cup showing consistent growth. Root irrigation was used to maintain the soil moisture content at 10°C. 9 The strain was inoculated again at an inoculum rate of CFU / g soil to enhance the colonization effect of the strain. Figure 3 and Figure 4As shown, the addition of 1.5‰ NaCl significantly inhibited soybean seedling emergence, while the G37-2 strain completely eliminated the inhibitory effect of NaCl stress on soybean seedling emergence. Specifically, NaCl treatment reduced the soybean seedling emergence rate from 85% in the control treatment to 45%. After inoculation with the G37-2 strain, the emergence rate in the NaCl+G37-2 treatment returned to 90%, comparable to the control treatment, indicating that the G37-2 strain completely eliminated the inhibitory effect of NaCl stress on soybean seedling emergence.

[0074] Figure 4 Different lowercase letters in the bar graphs indicate significant differences, P < 0.05.

[0075] 2. The effect of strain G37-2 in promoting soybean seedling growth under salt stress.

[0076] The test soil, potting setup, bacterial suspension preparation and inoculation, soybean sowing, and cultivation methods were the same as previously described. Twenty-five days after soybean sowing, plant height, aboveground fresh weight, root fresh weight, and functional leaf area (functional leaf area was defined as the inverted third leaf) were measured.

[0077] The results are as follows Figure 5 、 Figure 6 and Figure 7 As shown, compared with the control without NaCl addition, NaCl addition significantly inhibited soybean growth, manifested by significant decreases in plant height, aboveground fresh weight, upper third leaf area, and root fresh weight. Inoculation with the G37-2 strain effectively eliminated the inhibitory effects of NaCl on soybean growth, even exceeding the control in some indicators. Specifically, 11 days after sowing, NaCl treatment reduced soybean plant height by 54.9% compared with the control. However, inoculation with G37-2 restored plant height to levels comparable to the control. 25 days after sowing, NaCl treatment reduced soybean plant height by 12.8% compared with the control. Inoculation with G37-2 not only eliminated the inhibitory effects of NaCl on plant height, but also increased plant height to exceed that of the control without NaCl addition. 25 days after sowing, NaCl treatment reduced aboveground fresh weight and upper third leaf area by 27.8% and 31.4% compared with the control. However, inoculation with G37-2 restored aboveground fresh weight and upper third leaf area to levels comparable to the control. NaCl treatment reduced root fresh weight to 46.2% of the control, but inoculation with G37-2 restored root fresh weight to 73.7% of the control. These studies demonstrate that the G37-2 strain significantly alleviates the inhibitory effects of NaCl stress on soybean growth, restoring indicators such as plant height, aboveground fresh weight, upper third leaf area, and root fresh weight to levels approaching or exceeding those of the control.

[0078] Figure 6 and Figure 7 Different lowercase letters in the bar graphs indicate significant differences, P < 0.05.

[0079] 3. Under salt stress, the G37-2 strain stably colonizes the soybean rhizosphere.

[0080] The test soil, potting setup, bacterial suspension preparation and inoculation, soybean sowing and culture conditions were the same as above. After 25 days of soybean culture, the rhizosphere soil of soybeans in the three treatments was collected by shaking the roots. For the treatment with NaCl addition and inoculation with G37-2, 1 g of soil was weighed and placed in a test tube containing 9 mL of sterile water, marked as 10 -1 Dilution, shake at 28°C and 180 rpm for 30 min, use a sterile pipette to draw 100 μL of suspension into a centrifuge tube containing 900 μL of sterile water, mix well and mark as 10 -2 Repeat the above steps to prepare 10 -3 , 10 -4 , 10 -5 , 10 -6 Use a sterile pipette to draw 100 μL of the suspension with a dilution of 10 -4 , 10 -5 and 10 -6 The soil suspension was added dropwise to the surface of the LB solid culture medium and spread evenly. The plate was inverted and incubated at 28°C for 72 hours. A plate with a moderate number of colonies was selected, usually 30 to 300 colonies per plate. Based on the colony morphology of G37-2, the G37-2 colonies were counted to detect the number of colonization of the inoculated strain G37-2 in the rhizosphere soil. A single colony with the same colony morphology as the inoculated strain G37-2 was picked with a toothpick and placed in a 50 μL PCR reaction system. The 16S rRNA gene was amplified by PCR using universal bacterial primers 27F and 1492R. The PCR product was sent to Beijing Liuhe BGI Genomics Technology Co., Ltd. for sequencing. The 16S rRNA gene sequence obtained by sequencing was uploaded to EzBioCloud for homology comparison. The results showed that the 16S rDNA sequences of the colonies on the test plates shared 99.78% to 99.93% similarity with Glutamicibacter halophytocola KLBMP 5180 (Type), as shown in Table 1. This indicates that the colonies belong to Glutamicibacter halophytocola, consistent with the biological taxonomic status of the inoculated strain G37-2. Counting individual colonies with identical morphology to the inoculated G37-2 strains revealed that G37-2 was still able to colonize the soybean rhizosphere soil at harvest time, 25 days after sowing, reaching a colony size of 1.38 ± 0.16 × 10 7 CFU / g soil.

[0081] Table 1 Colonization test of soybean G37-2 in rhizosphere soil 25 days after sowing under salt stress

[0082]

[0083] 4. The effect of strain G37-2 on promoting rapeseed seed germination under salt stress.

[0084] Preparation of bacterial solution: G37-2 strain was inoculated into LB liquid medium, cultured at 28°C and 180 rpm for 17 h, centrifuged and collected, resuspended in 150 mM NaCl solution, and adjusted the bacterial solution OD 600 A value of 1.0 indicates a viable count of 10 9 CFU / mL, set aside.

[0085] Preparation of Petri dishes: Place two layers of sterile filter paper in 9 cm diameter Petri dishes, making a total of 15 Petri dishes.

[0086] Seed disinfection: Soak the rapeseed seeds in 75% ethanol by volume for 30 seconds and rinse once with sterile water; then soak the seeds in 15% H2O2 by mass for 30 seconds and rinse three times with sterile water to ensure that the seed surface is sterile.

[0087] The salt concentration settings are shown in Table 2.

[0088] Table 2 Salt concentration treatment of rapeseed seeds

[0089]

[0090]

[0091] Each treatment group in Table 2 was repeated three times.

[0092] Seed sowing: Add 10 mL of the solution from Table 2 to each Petri dish. Sow 15 sterilized rapeseed seeds per dish. Place the dishes in a 25°C incubator. After 5 days of incubation, measure radicle and shoot lengths.

[0093] The results in Table 3 show that 150 mM NaCl stress significantly inhibited rapeseed germination, radicle, and shoot growth. Compared to the sterile water control, 150 mM NaCl reduced rapeseed germination by 11.1%, shoot length by 87.0%, and radicle length by 97.6%. Inoculation with 1%, 10%, and 50% concentrations of the G37-2 bacterial solution restored germination to levels comparable to the control. Inoculation with a certain concentration of the G37-2 bacterial solution significantly alleviated the inhibitory effects of NaCl stress on root and shoot growth. Specifically, under NaCl stress, the radicle length of rapeseed was only 8.1mm, and the shoot length was only 21.3mm; inoculation with 10% G37-2 bacterial solution significantly increased the radicle length and shoot length to 25.9mm and 43.3mm, respectively, which were 2.19 times and 1.03 times higher than those in the NaCl treatment; in addition, inoculation with 50% G37-2 bacterial solution also significantly increased the radicle length of rapeseed, which was 51.8% higher than that in the NaCl treatment. In summary, inoculation with G37-2 bacterial solution can significantly alleviate the inhibitory effect of NaCl stress on rapeseed germination, and inoculation with 10% G37-2 bacterial solution is particularly effective in alleviating the inhibitory effect of NaCl on radicle and shoot growth. The effect of strain G37-2 on promoting rapeseed seed germination under NaCl stress is shown in the figure. Figure 8 .

[0094] Table 3 Radicle length and shoot length of rapeseed under different treatments

[0095] deal with Germination rate / % Radicle length / mm Bud length / mm <![CDATA[H2O]]> 90.0±4.7a 342.9±10.8a 164.3±21.1a 150NaCl 80.0±6.7b 8.1±0.7d 21.3±4.2c 150NaCl+1%G37-2 91.1±3.8a 15.8±2.7cd 37.3±3.7bc 150NaCl+10%G37-2 91.1±3.8a 25.9±4.1b 43.3±2.9b 150NaCl+50%G37-2 91.1±3.8a 19.3±1.4bc 32.4±5.3bc

[0096] Note: In Table 3, different lowercase letters in the same column of germination rate, radicle length and shoot length indicate significant differences, P < 0.05.

[0097] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0098] The above-described embodiments merely illustrate several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, and all such variations and improvements fall within the scope of protection of the present invention.

Claims

1. A glutamic acid bacillus salt-tolerant plant, characterized in that: The halophytic glutamicum bacillus is Glutamicibacter halophytocola G37-2, with a preservation number of CCTCC NO: M20242581, and was deposited in the China Center for Type Culture Collection on November 18, 2024.

2. A bacterial suspension, characterized in that The bacterial suspension is obtained by culturing the halogenated glutamicum according to claim 1, and the culturing process is as follows: Inoculate glutamicum salinarum into LB medium, culture at 28℃~30℃, 160rpm~200rpm for 16h~18h, collect bacteria, and adjust the viable bacteria count of glutamicum salinarum to 10 with sterile water. 9 CFU / mL, and the bacterial suspension is obtained.

3. The bacterial suspension according to claim 2, wherein The process of the cultivation is as follows: Inoculate glutamicum salinarum into LB medium and culture at 28°C and 180 rpm for 17 h. Collect the cells and adjust the viable count of glutamicum salinarum to 10 with sterile water. 9 CFU / mL, and the bacterial suspension is obtained.

4. The use of the bacillus salinarum as claimed in claim 1 or the bacterial suspension as claimed in claim 2, characterized in that, The application refers to any of the following: 1) Promote crop emergence; 2) Promote the growth of crops in seedling stage; 3) Promote crop seed germination; 4) Improve crop salt tolerance.

5. The use according to claim 4, characterized in that The crop includes any one of soybean and rapeseed.

6. A microbial growth promoter, characterized in that: The microbial growth promoter comprises the halogenated glutamicum according to claim 1, and the number of viable bacteria of the halogenated glutamicum in the microbial growth promoter is 10 9 CFU / mL.

7. A microbial germination promoter, characterized in that: The microbial germination promoter comprises the halogenated glutamicum according to claim 1, and the number of viable bacteria of the halogenated glutamicum in the microbial germination promoter is 10 9 CFU / mL.

8. The microbial growth-promoting agent according to claim 6 or the microbial germination-promoting agent according to claim 7, characterized in that: The microbial growth-promoting agent or microbial bud-promoting agent further comprises microbiologically acceptable auxiliary materials.

9. The microbial growth-promoting agent or microbial bud-promoting agent according to claim 8, characterized in that: The microbiologically acceptable excipients include at least one of a filler, a binder, a disintegrant, a lubricant and an antacid.

10. The microbial growth-promoting agent according to claim 6 or the microbial germination-promoting agent according to claim 7, characterized in that: The application method of the microbial growth-promoting agent or the microbial bud-promoting agent includes any one of spraying, root irrigation, seed dressing and seed soaking.

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