A salt-alkali tolerant rhizobium strain GLJ-SYP-2 and its application

Abstract

The invention provides a salt-alkali tolerant rhizobium GLJ-SYP-2 and an application thereof, belonging to the technical field of microorganisms. The rhizobium GLJ-SYP-2 provided by the invention can tolerate a high alkaline environment of pH 13, a NaCl salt environment of 4.0%, and a drought environment of PEG6000 of 25%. A rhizobium agent is prepared based on the rhizobium GLJ-SYP-2, which can adapt to the high salt-alkali environment of saline-alkali land, has a good effect of promoting plant nodulation, and is beneficial to the improvement of the yield and quality of plants grown in saline-alkali land.

Description

Technical Field

[0001] The invention belongs to the technical field of microorganisms, and in particular relates to a salt-alkali resistant rhizobium GLJ-SYP-2 and an application thereof. Background Art

[0002] Alfalfa, a legume forage, is known as the "king of forage" because it is rich in protein, various amino acids and vitamins required by animals and other nutrients. It can effectively improve milk production and quality. However, most alfalfa is planted on saline-alkali land and sloping land, most of which do not meet the high-standard requirements for grass planting. As the main arable land for alfalfa production, saline-alkali land has poor soil nutrients, unbalanced soil microbial community structure, and a small number of indigenous rhizobia. The root nodulation rate of alfalfa after planting is extremely low, resulting in low alfalfa yield, poor quality, and poor planting benefits.

[0003] Rhizobia, which coexists with legumes, will coexist with legumes to form nodules after entering the root system of legumes, converting molecular nitrogen in the air into ammonia nitrogen that can be used by legumes. It is the most efficient biological nitrogen fixation system, which can provide 1 / 3 to 1 / 2 of the required nitrogen for legumes. For the perennial legume alfalfa, the nitrogen fixation amount can reach 100 to 150 kg per hectare per year. The number of effective rhizobia in the soil is an important factor in determining alfalfa yield. The symbiotic system of rhizobia and alfalfa can effectively improve the nitrogen fixation efficiency of nodules, promote the growth of alfalfa, and increase the dry matter and crude protein content of alfalfa; it can improve the osmotic regulation and antioxidant capacity of alfalfa under low temperature stress, maintain normal photosynthesis of alfalfa under low temperature conditions, and enhance the stress resistance of alfalfa; it can improve the distribution of microorganisms in the roots of alfalfa, increase soil enzyme activity, and improve the soil fertility of the root soil environment. At present, it is necessary to screen out rhizobia suitable for saline-alkali soil, so as to develop saline-alkali reserve arable land to plant alfalfa, enhance the stress resistance of alfalfa, increase the yield and improve the quality of alfalfa, and at the same time promote the ecological reform and green and sustainable development of the alfalfa industry. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a salt-alkali tolerant rhizobium GLJ-SYP-2 and its application. The rhizobium GLJ-SYP-2 can tolerate high alkaline environment, high salt environment, and drought environment, and has a good nodulation effect on plants grown in saline-alkali soil (especially moderate to severe saline-alkali land).

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a salt-alkali tolerant rhizobium (Sinorhizobium meliloti) GLJ-SYP-2,

[0007] The deposit number of the rhizobium GLJ-SYP-2 is CCTCC NO:M 2020470.

[0008] Preferably, the nucleotide sequence of 16S rRNA of the rhizobium GLJ-SYP-2 is shown in SEQ ID No.1.

[0009] The invention provides application of the rhizobium GLJ-SYP-2 in promoting the growth of plants in saline-alkali land, wherein the plants include alfalfa.

[0010] The invention provides application of the rhizobium GLJ-SYP-2 in improving the nodulation rate of plants, wherein the plants include alfalfa.

[0011] The invention provides application of the rhizobium GLJ-SYP-2 in improving saline-alkali land.

[0012] The present invention provides a rhizobium agent, comprising the following components in parts by weight:

[0013] The rhizobium GLJ-SYP-2 comprises 5 to 10 parts, pseudomonas comprises 5 to 10 parts, a protective agent comprises 5 to 10 parts, and a carrier comprises 70 to 85 parts.

[0014] Preferably, the protective agent is gelatin or skimmed milk powder.

[0015] Preferably, the carrier is straw powder and peat soil, and the mass ratio of the straw powder to the peat soil is 1:3-10.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The rhizobium GLJ-SYP-2 provided by the present invention can tolerate a high alkaline environment of pH 13, a NaCl salt environment of 4.0%, and a drought environment of PEG6000 of 25%. The rhizobium agent is prepared based on the salt-alkali tolerant rhizobium, can adapt to the high saline-alkali environment of saline-alkali land, has a good effect of promoting plant nodulation, and is beneficial to the improvement of the planting yield and quality of plants in saline-alkali land. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The effect of different pH on the growth of rhizobium GLJ-SYP-2;

[0019] Figure 2 The effect of different salt stresses on the growth of rhizobium GLJ-SYP-2;

[0020] Figure 3 The effects of different drought stresses on the growth of rhizobium GLJ-SYP-2;

[0021] Figure 4The growth of alfalfa in the rhizobium-treated group and the control group;

[0022] Figure 5 The data graphs of root length and stem length of different treatment groups;

[0023] Figure 6 It is the nodulation data graph of different treatment groups;

[0024] Figure 7 This is a data chart showing the total nitrogen content of alfalfa plants in different treatment groups determined using the Kjeldahl method.

[0025] Biological Deposit Description

[0026] The rhizobium Sinorhizobium meliloti GLJ-SYP-2 provided by the present invention was deposited in the China Center for Type Culture Collection on September 7, 2020, with the deposit address being Wuhan University, Wuhan, China, and the deposit number being CCTCC NO:M2020470. DETAILED DESCRIPTION

[0027] The present invention provides a salt- and alkali-tolerant rhizobium (Sinorhizobium meliloti) GLJ-SYP-2, which was deposited in the China Center for Type Culture Collection on September 7, 2020, with the deposit address being Wuhan University, Wuhan, China, and the deposit number being CCTCC NO:M 2020470.

[0028] The rhizobium GLJ-SYP-2 provided by the present invention has transparent, convex, smooth, moist and round colonies on a YMA plate. The strain can tolerate a high alkaline environment of pH 13, a NaCl salt environment of 4.0%, and a drought environment of PEG6000 of 25%.

[0029] In the present invention, the nucleotide sequence of 16S rRNA of the rhizobium GLJ-SYP-2 is shown in SEQ ID No. 1;

[0030] SEQ ID No.1:

[0031]

[0032] The present invention provides the use of the rhizobium GLJ-SYP-2 in promoting the growth of plants in saline-alkali land, wherein the plants preferably include alfalfa, and the rhizobium GLJ-SYP-2 can significantly increase the yield and crude protein content of the plants.

[0033] The present invention provides the use of the rhizobium GLJ-SYP-2 in improving the nodulation rate of plants. The plants preferably include alfalfa. The rhizobium GLJ-SYP-2 can significantly increase the nodulation amount of the plants.

[0034] The present invention provides the application of the rhizobium GLJ-SYP-2 in improving saline-alkali land. The rhizobium GLJ-SYP-2 promotes plant growth and enables the plant to secrete more organic acids and the like to form a complex with sodium salt in the soil, thereby improving the soil structure. The rhizobium GLJ-SYP-2 can also utilize the transpiration effect of the plant to reduce the salt concentration in the soil, thereby achieving the effect of improving the soil.

[0035] The invention provides a rhizobium agent, which comprises the following components in parts by weight: 5 to 10 parts of the rhizobium GLJ-SYP-2, 5 to 10 parts of pseudomonads, 5 to 10 parts of a protective agent, and 70 to 85 parts of a carrier.

[0036] In the present invention, the rhizobium GLJ-SYP-2 is 5 to 10 parts, preferably 6 to 9 parts, and more preferably 7 parts, and the rhizobium GLJ-SYP-2 can significantly increase the amount of plant nodules;

[0037] 5 to 10 parts of Pseudomonas, preferably 6 to 9 parts, more preferably 7 parts, with a live bacterial concentration of 5.0 to 10.0×10 8 cfu / mL; the Pseudomonas PYX-1 strain was deposited in the China Center for Type Culture Collection on October 30, 2023, with a deposit number of CCTCC No: M20232078, and has been disclosed in patent CN202410933773.9. The strain has the functions of solubilizing phosphate and producing siderophores, with a phosphate solubilizing efficiency of 303.51 mg / L and a relative content of siderophores of 58.70%. It can significantly regulate the microecological environment of plants and enhance the colonization ability of rhizobia in plants, especially in the rhizosphere of alfalfa.

[0038] 5 to 10 parts of protective agent, preferably 6 to 9 parts, more preferably 7 parts; in the present invention, the protective agent is preferably gelatin or skimmed milk powder; Rhizobium and Pseudomonas are both negative bacteria with low cell survival rate, gelatin and skimmed milk powder have a large number of hydroxyl groups, as well as many carboxyl groups and amino groups, and have good colloid protection, surface activity, viscosity, film-forming property and stability. Under the protection of gelatin and skimmed milk powder, the survival rate of Rhizobium and Pseudomonas can be prolonged.

[0039] The carrier is 70-85 parts, preferably 75-80 parts, and more preferably 77 parts. The carrier is preferably straw powder and peat soil, and the mass ratio of the straw powder to peat soil is preferably 1:3-10, more preferably 1:5-8, and even more preferably 1:6.

[0040] On the one hand, the carrier is rich in organic matter and humic acid. The addition of the carrier can not only improve the survival rate of rhizobia and pseudomonas, but also improve the colonization ability of rhizobia and pseudomonas in the soil. On the other hand, the liquid rhizobia agent needs to be dried after mixing with alfalfa seeds, which increases the application cost, but the solid rhizobia powder can be applied immediately after mixing with alfalfa seeds.

[0041] The straw powder is rice or wheat straw, and the grinding mesh is above 60 mesh. The peat soil is commercially available, and the mesh of the carrier is above 60 mesh. The straw powder and the peat soil are mixed according to a certain proportion, sterilized in a sterilizing pot and set aside.

[0042] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0043] Sources

[0044] Gelatin was purchased from Sinopharm Group, CAS No. 9000-70-8;

[0045] The genome extraction kit was purchased from Tiangen Company;

[0046] Methyl red was purchased from Sinopharm Group, CAS No. 493-52-7;

[0047] Skim milk powder was purchased from JD Supermarket, the brand is Yili;

[0048] Rice and wheat straw powder were purchased from Taobao Huifeng Straw Agricultural Products Deep Processing Store;

[0049] The peat soil was purchased from the Changbai Mountain Forest Store on Taobao.

[0050] Example 1 Isolation and identification of rhizobium GLJ-SYP-2 strain

[0051] (1) Strain source

[0052] The Congo red YMA culture medium is separated from saline-alkali soil in Inner Mongolia. The composition of the Congo red YMA culture medium is 10 g / L of mannitol, 0.1 g / L of NaCl, 0.2 g / L of MgSO4·7H2O, 1 g / L of yeast powder, 0.5 g / L of K2HPO4, 15-20 g / L of agar, 4 ml / L of 0.5% Congo red solution and 1000 ml / L of distilled water. The pH value of the Congo red YMA culture medium is 7.0-7.2.

[0053] (2) Separation

[0054] 8 to 10 large, pink nodules were selected from fresh nodules of alfalfa planted in saline-alkali land of Inner Mongolia, the soil was rinsed off with water, and the nodules were soaked in 75% ethanol for 1 min, rinsed with water 3 to 4 times, soaked in 5% sodium hypochlorite solution for 1 min, rinsed with water 5 to 6 times, ground in a sterilized mortar, and a small amount of nodule juice was picked out with an inoculation needle. The nodule was inoculated onto Congo red YMA plate culture medium in a 90 mm culture dish by streaking or smearing method, and cultured upside down in a 30°C biochemical incubator. The colonies grown on the YMA medium were separated according to their size, color and shape. Colonies with the same size, color and shape were selected and a ring was picked up with an inoculation needle and inoculated onto the Congo red YMA flat medium. The plates were then placed in a 30°C biochemical incubator and inverted for culture for 2-3 days. After several selections, separations and purifications, the size, color and shape of the rhizobia colonies on the medium in each culture dish were consistent. After screening for physiological and biochemical characteristics and different stress conditions, the purified strain GLJ-SYP-2 was obtained and inoculated onto a test tube slant for storage.

[0055] (3) Identification

[0056] Gene sequencing was used to classify and identify the GLJ-SYP-2 strain. The specific steps are as follows:

[0057] (3.1) Preparation of bacterial total DNA: The genomic DNA of the GLJ-SYP-2 strain was extracted using a genome extraction kit and used as a template for the PCR reaction.

[0058] (3.2) PCR amplification of genes:

[0059] The following amplification primers were used:

[0060] First primer 27F:

[0061] SEQ ID NO:2:

[0062] 5'-AGAGTTTGATCMTGGCTCAG-3'[M=C,A];

[0063] Second primer 1492R:

[0064] SEQ ID NO:3:

[0065] 5'-CGGYTACCTTGTTACGACTT-3'[Y=T,C].

[0066] The PCR reaction system is shown in Table 1.

[0067] Table 1 PCR reaction system

[0068]

[0069] The PCR reaction conditions were: (pre-denaturation at 95°C for 5 minutes)-(denaturation at 94°C for 1 minute, annealing at 55°C for 30 seconds, extension at 72°C for 2 minutes)×35 cycles-(extension at 72°C for 10 minutes).

[0070] (3.3) Purification, cloning, sequencing and analysis of PCR products:

[0071] The PCR product was sent to Shanghai Sangon Biotechnology Co., Ltd. for sequencing, and the 16S rRNA gene sequence was determined. The gene sequence was logged into the website of the National Center for Biotechnology Information (http: / / www.ncbi.nlm.nih.gov) of the United States, and a nucleotide sequence Blast comparison was performed to obtain several nucleotide sequences homologous to the 16S rRNA gene sequences of related strains. The results showed that the homology of the 16S rRNA gene sequences of the GLJ-SYP-2 strain and Sinorhizobium meliloti was more than 99%, and the isolated strain was identified as Sinorhizobium meliloti.

[0072] (4) The morphological identification characteristics of the rhizobium GLJ-SYP-2 strain are as follows:

[0073] The GLJ-SYP-2 strain belongs to the Gram-negative bacteria. The colonies on the YMA plate are transparent, raised, smooth, moist, sticky and round.

[0074] Example 2 Physiological and biochemical characteristics of Sinorhizobium meliloti GLJ-SYP-2 strain

[0075] (1) Detection of glucose metabolites of strains using VP test

[0076] Culture medium preparation: 5 g peptone, 5 g glucose, 5 g NaCl, 1000 ml distilled water, adjust pH to 7.0-7.2, divide into test tubes, 4-5 ml per tube, sterilize at 121°C for 20 min.

[0077] Reagents: 40% KOH, 6% α-naphthol pure alcohol solution.

[0078] Under aseptic operation, inoculate the test strain into the above culture medium, culture at 30℃ for 4 days, take 2.5ml of culture medium, first add 0.6ml of α-naphthol pure alcohol solution, then add 0.2ml of 40% KOH aqueous solution, shake for 2-5min, if it turns red immediately, the strain has the ability to produce diacetyl, which is positive. If no red color appears, place it in a 30℃ constant temperature box. If no red color appears within 2h, it can be judged as negative.

[0079] (2) Using the methyl red test to detect the acid production ability of the strain

[0080] Culture medium preparation: same as step (1) of Example 2.

[0081] Reagents: 0.02 g methyl red, 60 ml 95% alcohol, 40 ml distilled water, to prepare methyl red solution.

[0082] Under aseptic operation, inoculate the test bacteria into the above culture medium and culture at 30℃ for 4 days. Add a few drops of methyl red solution to the culture medium. If the culture medium turns red, it is positive and the strain has the ability to produce acid. If the culture medium turns yellow, it is negative.

[0083] (3) Using gelatin hydrolysis test to detect the ability of strains to produce gelatinase

[0084] Medium preparation: 0.5 g peptone, 12 g gelatin, 100 ml distilled water, pH: 7.2-7.4. Dispense into test tubes, 4-5 ml per tube, sterilize at 121°C for 20 min.

[0085] Under aseptic operation conditions, pick the test bacteria and puncture inoculate them into the gelatin layer at about 2 / 3 of its depth. Culture at 20℃ for 7 to 14 days and observe the experimental results every day. If the gelatin itself is liquefied due to the high culture temperature, it should not be shaken. Let it stand in the refrigerator until it solidifies and observe whether the bacteria are liquefied by the bacteria. If so, the gelatin hydrolysis is positive and the bacteria can produce gelatinase. Otherwise, it is negative.

[0086] (4) Catalase activity

[0087] Add 1 drop of 3% H2O2 on a clean slide, pick up 1 loop of test bacteria with an inoculation loop, smear it in the H2O2, if bubbles are produced it is positive, otherwise it is negative.

[0088] (5) Qualitative test for indoleacetic acid (IAA) production: The strains were inoculated into YMA liquid culture medium (containing 100 mg / L L-tryptophan) and cultured on a shaker at 37°C and 180 r / min for 1 day. 50 μL of the supernatant of the bacterial suspension after centrifugation at 8000 r / min was taken, 50 μL of Salkowski colorimetric solution was added, and the suspension was dropped onto a white porcelain plate in the dark for 30 min. If a pink color appeared, it was positive, indicating that the strain was able to secrete IAA. The darker the color, the stronger the secretion intensity. No color change was negative, indicating that the strain could not secrete IAA.

[0089] The results of steps (1) to (5) are shown in Table 2.

[0090] Table 2 Physiological and biochemical characteristics of GLJ-SYP-2 strain

[0091]

[0092] +: positive reaction; -: negative reaction

[0093] After testing, the rhizobium VP reaction, methyl red test, and gelatin hydrolysis test were negative, and catalase and indoleacetic acid production were positive. The negative results of VP reaction and methyl red test indicate that the rhizobium GLJ-SYP-2 does not produce pyruvate by using the glucose metabolic pathway; the negative results of gelatin hydrolysis indicate that the rhizobium GLJ-SYP-2 does not produce extracellular gelatinase; the positive results of catalase indicate that the rhizobium GLJ-SYP-2 can catalyze hydrogen peroxide to produce water and new ecological oxygen, which can help crops improve their stress resistance. The rhizobium GLJ-SYP-2 has a significant ability to produce indoleacetic acid, and secreting indoleacetic acid in the soil can promote crop growth.

[0094] Example 3 Resistance determination of rhizobium GLJ-SYP-2 under different stress conditions

[0095] (1) Alkali resistance: YMA medium was used as the base medium. NaOH or HCl solution was used to adjust the initial pH value of YMA liquid medium to 7.0, 8.0, 9.0, 10.0, 11.0, 12.0, and 13.0. The seed solution was prepared with YMA liquid medium at pH 7.0. The seed solution was inoculated with 2% of the inoculum into YMA liquid medium at different pH values. The seed solution was cultured at 30°C and 200 rpm for 48 h. The OD600 of the culture solution was detected. The results are shown in Table 1. Figure 1 .

[0096] Depend on Figure 1 It can be seen that with the increase of pH, the OD600 value of the GLJ-SYP-2 strain showed a trend of first increasing and then decreasing. The optimal pH value was 11, and the strain could tolerate alkaline stress of pH 13.

[0097] (2) Salt tolerance: YMA medium was used as the base medium, and YMA culture fluids containing 1.0%, 2.0%, 3.0%, 4.0%, and 5.0% NaCl were prepared. The seed solution was prepared using YMA liquid medium with a pH of 7.0. The inoculum was inoculated with 2% of the seed solution into YMA liquid medium with different NaCl concentrations, and cultured at 30°C and 200 rpm for 48 h. The OD600 of the culture fluid was detected. The results are shown in Table 1. Figure 2 .

[0098] Depend on Figure 2It can be seen that with the increase of NaCl concentration, the OD600 value of the GLJ-SYP-2 strain showed a trend of first increasing and then decreasing. The optimal NaCl concentration was 1%, and the strain could tolerate a salt stress of 4.0% NaCl concentration.

[0099] (3) Drought resistance: YMA medium was used as the base medium, and liquid culture solutions containing 10%, 15%, 20%, 25%, and 30% PEG6000 were prepared. The seed solution was prepared using YMA liquid culture medium with a pH of 7.0, and the inoculum was inoculated with 2% into YMA liquid culture medium with different concentrations of PEG6000. The culture was cultured at 30°C and 200 rpm for 48 h, and the OD600 of the culture solution was detected. The results are shown in Table 1. Figure 3 .

[0100] Depend on Figure 3 It can be seen that with the increase of PEG6000 concentration, the growth of GLJ-SYP-2 strain showed a decreasing trend, and the strain could tolerate drought stress at a maximum PEG6000 concentration of 25%.

[0101] Example 4: Nodulation and nitrogen fixation ability of rhizobium GLJ-SYP-2

[0102] Soak alfalfa seeds in 95% ethanol solution for 30 seconds. After the ethanol solution is poured off, add 5% sodium hypochlorite solution and soak the seeds for 5 minutes. Then wash with sterile water 5 times for later use. Sow the treated alfalfa seeds in sterilized vermiculite basins and divide them equally into SYP-2 group and control group. Add bacterial suspension of GLJ-SYP-2 fermentation liquid diluted with distilled water to the SYP-2 group, and add distilled water to the control group. Repeat 10 times. Alfalfa is cultured in a greenhouse with a light intensity of 10,000 lx and 12 hours of light per day. Nitrogen-free culture solution is added during this period. Plant samples are taken for determination after 20 days of culture. The growth of different treatment groups is shown in Figure 4 ; Data on root and stem length of different treatment groups are shown in Figure 5 ; Nodulation data of different treatment groups are shown in Figure 6 The total nitrogen content of alfalfa plants in different treatment groups was determined by Kjeldahl method. Figure 7 .

[0103] Depend on Figure 5 It can be seen that compared with the control group, the root length increased by 57.62% and the stem length increased by 57.53% after inoculation with rhizobia. Figure 6 It can be seen that compared with the control group, the total nodule number of alfalfa increased by 144.44% and the effective nodule number increased by 168.96% after inoculation with rhizobia. Figure 7 It can be seen that compared with the control group, the nitrogen content of alfalfa plants increased by 17.75% after inoculation with rhizobia.

[0104] Example 5: Preparation of Rhizobium Agent of Rhizobium GLJ-SYP-2

[0105] The rhizobium GLJ-SYP-2 fermentation liquid, the pseudomonas fermentation liquid, the protective agent and the organic carrier are mixed together in a certain proportion to prepare a rhizobium agent, the specific components of which are: 10 parts of rhizobia, 10 parts of pseudomonas, 10 parts of protective agent, 10 parts of straw powder and 60 parts of peat soil, wherein the straw powder and peat soil are sterilized at high temperature.

[0106] Example 6: Field test of rhizobium GLJ-SYP-2 fermentation liquid and rhizobium inoculant for alfalfa cultivation in saline-alkali land

[0107] The field experiment was conducted by setting no bacterial agent as CK, alfalfa seeds coated with GLJ-SYP-2 rhizobium fermentation liquid as T1, and alfalfa seeds coated with rhizobium agents as T2. Three parallels were set for each treatment, and the area of ​​each plot was 1 mu. The alfalfa seeds in the T1 and T2 treatment groups were coated with rhizobia: seeds = 1:20 and then dried in the shade and sown. The alfalfa variety was bright alfalfa, and the planting site was Alukeerqin Banner, Inner Mongolia. Soil was collected before planting for analysis. The physical and chemical properties of the soil are shown in Table 3. The soil alkalinity ESP was 26.68%, and the pH was 8.79, which was a medium to severe saline-alkali land.

[0108] Table 3 Physical and chemical properties of soil in the test plots

[0109]

[0110] After one planting season, the alfalfa yield and quality of each treatment group in the field experiment are shown in Table 4.

[0111] Table 4 Nodulation, yield and crude protein content of alfalfa under different experimental treatments

[0112]

[0113] It can be seen that inoculation with rhizobium fermentation liquid or rhizobium agent can significantly increase the nodulation rate of alfalfa, by 60.0% and 72.3% respectively; inoculation with rhizobium fermentation liquid or rhizobium agent can significantly increase the dry weight of alfalfa, by 19.03% and 22.72% respectively; inoculation with rhizobium fermentation liquid or rhizobium agent can significantly increase the crude protein content of alfalfa, by 17.61% and 26.83% respectively.

[0114] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A salt-alkali tolerant rhizobium (Sinorhizobium meliloti) GLJ-SYP-2, characterized in that: The deposit number of the rhizobium GLJ-SYP-2 is CCTCC NO:M 2020470.

2. The rhizobium GLJ-SYP-2 according to claim 1, characterized in that The nucleotide sequence of 16SrRNA of the rhizobium GLJ-SYP-2 is shown in SEQ ID No.

1.

3. Use of the rhizobium GLJ-SYP-2 according to claim 1 or 2 in promoting the growth of plants in saline-alkali land, characterized in that: The plants include alfalfa.

4. Use of the rhizobium GLJ-SYP-2 according to claim 1 or 2 in improving plant nodulation rate, characterized in that: The plants include alfalfa.

5. Use of the rhizobium GLJ-SYP-2 according to claim 1 or 2 in improving saline-alkali land.

6. A rhizobium agent, characterized in that: The composition includes the following components in parts by weight: 5 to 10 parts of the rhizobium GLJ-SYP-2 of claim 1, 5 to 10 parts of Pseudomonas, 5 to 10 parts of a protective agent, and 70 to 85 parts of a carrier.

7. A rhizobium agent according to claim 6, characterized in that: The protective agent is gelatin or skimmed milk powder.

8. A rhizobium agent according to claim 6, characterized in that: The carrier is straw powder and peat soil, and the mass ratio of the straw powder to the peat soil is 1:3-10.

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