Halomonas HRKJ-6 and application of zymocyte agent of halomonas HRKJ-6 in plant growth promotion

Abstract

The invention belongs to the technical field of microbial fermentation, and particularly relates to application of halomonas HRKJ-6 and a zymocyte agent thereof in plant growth promotion. The strain is preserved in the China General Microbiological Culture Collection Center (CGMCC), and the preservation number is CGMCC No.33015. The HRKJ-6 strain has relatively high alkali resistance and high-salt environment tolerance. Experimental results show that by applying the HRKJ-6 strain fermentation inoculant, the emergence rate and plant height of medicago sativa in a saline-alkali environment can be remarkably increased. Therefore, the strain provided by the invention has important economic value and ecological significance in the aspect of plant growth promotion.

Description

Technical Field

[0001] The present invention belongs to the technical field of microbial fermentation, and particularly relates to an application of a Halomonas strain HRKJ-6 and its fermentation inoculant in promoting plant growth. Background Art

[0002] Saline-alkali soil is a special type of soil formed by the combined action of natural environmental factors (such as climate, terrain, groundwater level, etc.) and human activities (such as unreasonable irrigation, overgrazing, etc.). Its main characteristic is that the soil contains a relatively high concentration of soluble salts, resulting in the deterioration of soil structure, the decline of soil fertility, and the inhibition of plant growth. In China, the area of saline-alkali land is approximately 99.13 million hectares. As important potential arable land resources, the comprehensive utilization of these lands is of great strategic significance for ensuring national food security and improving the ecological environment.

[0003] At present, the development and utilization of saline-alkali land face many challenges. The high-salt environment can cause plants to face problems such as osmotic stress, ion toxicity, and nutrient imbalance, thus restricting the normal growth and development of plants. Traditional methods for improving saline-alkali land mainly include physical measures such as drainage and salt washing, chemical measures such as applying gypsum or lime, and biological measures such as planting salt-tolerant plants. However, these methods usually have problems such as high costs, difficult-to-sustain effects, or possible secondary environmental pollution, which limit their large-scale promotion.

[0004] In recent years, the application of microbial technology in the agricultural field has opened up new ways for saline-alkali land improvement. Some microorganisms can enhance the stress resistance and growth ability of plants through mechanisms such as secreting plant hormones, promoting nutrient absorption, and alleviating salt stress. Therefore, exploring and developing saline-alkali-tolerant microbial resources is of great significance for promoting plant growth under saline-alkali conditions. Summary of the Invention

[0005] The purpose of the present invention is to provide an application of a Halomonas strain HRKJ-6 and its fermentation inoculant in promoting plant growth, so as to improve the stress resistance and growth ability of plants in a moderately saline-alkali environment.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] In the first aspect, the present invention provides a Halomonas strain. The strain name of the Halomonas strain is Halomonas bachuensis HRKJ-6, which has been deposited with the China General Microbiological Culture Collection Center (CGMCC), located at No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing. The deposit date is December 10, 2024, and the deposit number is CGMCC No. 33015.

[0008] Preferably, the 16S rDNA sequence of Halomonas HRKJ-6 is as shown in SEQ ID NO.1.

[0009] In a second aspect, the present invention provides the use of a fermentation inoculum of Halomonas in the preparation of a growth promoter for promoting the emergence rate and growth of plants in saline-alkali soil.

[0010] Preferably, the saline-alkali soil is moderately saline-alkali soil, the plant is alfalfa, and the concentration of Halomonas HRKJ-6 in the fermentation inoculum is greater than or equal to 0.1×10 8 CFU / mL.

[0011] Preferably, in the fermentation inoculum, the concentration of Halomonas HRKJ-6 is 0.1×10 8 CFU / mL to 1×10 8 CFU / mL.

[0012] In a third aspect, the present invention provides a growth promoter for promoting the emergence rate and growth of plants in saline-alkali soil, and the growth promoter includes a fermentation inoculum of Halomonas HRKJ-6 with the preservation number of CGMCC No.33015;

[0013] In the fermentation inoculum, the concentration of Halomonas HRKJ-6 is greater than or equal to 0.1×10 8 CFU / mL.

[0014] Preferably, the saline-alkali soil is moderately saline-alkali soil; the plant is alfalfa; in the fermentation inoculum, the concentration of Halomonas HRKJ-6 is 0.1×10 8 CFU / mL to 1×10 8 CFU / mL.

[0015] In a fourth aspect, the present invention provides a method for promoting the emergence rate and growth of alfalfa in saline-alkali soil, and the method includes the following steps:

[0016] (1) After surface disinfection and germination promotion treatment of alfalfa seeds, sow them into the saline-alkali soil;

[0017] (2) Apply the fermentation inoculum of Halomonas HRKJ-6 with the preservation number of CGMCC No.33015 on the day of sowing;

[0018] (3) Apply the fermentation inoculum of Halomonas HRKJ-6 once every 10 days after sowing.

[0019] Preferably, in the fermentation inoculum, the saline-alkali soil is moderately saline-alkali soil, and the concentration of Halomonas HRKJ-6 is 0.1×10 8 CFU / mL to 1×10 8CFU / mL.

[0020] Preferably, the pH of the moderately saline-alkali soil is 8.4, and the electrical conductivity of the moderately saline-alkali soil is 4.62 mS / cm;

[0021] The alfalfa is Gongnong No. 1 alfalfa.

[0022] The beneficial effects of the present invention are as follows:

[0023] First of all, the HRKJ-6 strain provided by the present invention exhibits excellent alkali tolerance and high-salt environment adaptability. The experimental results show that the strain can survive in a wide range of pH from 4.5 to 10.5, and shows a better growth state in a neutral to alkaline environment (pH 7-10); at the same time, it can also survive and maintain a certain activity in a high-salt environment with a NaCl concentration of 5%-15%. This characteristic makes it particularly suitable for application in the fields of saline-alkali soil improvement and promotion of salt-tolerant crop growth.

[0024] Secondly, under the conditions of moderately saline-alkali soil (pH 8.4, electrical conductivity 4.62 mS / cm), applying the HRKJ-6 strain fermentation inoculant can significantly improve the emergence rate and plant height of alfalfa. The experimental results show that as the concentration of the fermentation inoculant increases from 0.1×10 8 CFU / mL to 1×10 8 CFU / mL, the emergence rate and plant height of alfalfa show a dose-dependent increase. This indicates that the HRKJ-6 strain has a significant plant growth-promoting effect and can effectively alleviate the inhibitory effect of saline-alkali stress on plant growth.

[0025] In addition, the HRKJ-6 strain can not only be used for saline-alkali land improvement and plant growth promotion, but also be used as a biological pesticide for disease control, with multiple functions. Its survival ability in extreme environments and excellent growth-promoting characteristics make it have broad application prospects in the fields of saline soil remediation, salt-tolerant crop cultivation, and development of extreme environment microbial resources. Description of the Drawings

[0026] Figure 1 are the morphological characteristics of the HRKJ-6 strain on a conventional LB medium;

[0027] Figure 2 are the effects of different pH values on the growth of the HRKJ-6 strain;

[0028] Figure 3 are the effects of different salt concentrations on the growth of the HRKJ-6 strain;

[0029] Figure 4 are the antibacterial activities of the HRKJ-6 strain against different strawberry pathogens;

[0030] Figure 5 The control effects of HRKJ-6 strains with different concentrations on strawberry root rot;

[0031] Figure 6 The effects of HRKJ-6 strains with different concentrations on the emergence rate of alfalfa;

[0032] Figure 7 The effects of HRKJ-6 strains with different concentrations on the plant height of alfalfa. Specific implementation manners

[0033] The following non-limiting examples can enable those of ordinary skill in the art to more comprehensively understand the present invention, but do not limit the present invention in any way. The following content is merely an exemplary illustration of the scope claimed by the present invention. Those skilled in the art can make various changes and modifications to the invention of the present invention based on the disclosed content, and it should also fall within the scope claimed by the present application.

[0034] The culture media used in the present invention are as follows:

[0035] Conventional LB medium: 5 g of yeast extract, 10 g of tryptone, 10 g of sodium chloride, 1 L of distilled water (NaCl is 1%).

[0036] 1 / 2LB medium: 2.5 g of yeast extract, 5 g of tryptone, 5 g of sodium chloride, 1 L of distilled water.

[0037] LB media with different pH values: LB media with pH values of 4.5, 5, 6, 7, 8, 9, and 10 respectively.

[0038] LB medium with 5% NaCl: 5 g of yeast extract, 10 g of tryptone, 50 g of sodium chloride, 1 L of distilled water.

[0039] LB medium with 10% NaCl: 5 g of yeast extract, 10 g of tryptone, 100 g of sodium chloride, 1 L of distilled water.

[0040] LB medium with 15% NaCl: 5 g of yeast extract, 10 g of tryptone, 150 g of sodium chloride, 1 L of distilled water.

[0041] PDA solid medium: 200 g of peeled potatoes, 20 g of glucose, 20 g of agar, 1 L of distilled water.

[0042] Example 1

[0043] Isolation of strains

[0044] In 2021, several strains of bacteria were isolated from the greenhouse soil in Urumqi, Xinjiang. The process is as follows:

[0045] Add the obtained 1 g soil sample to a sterilized 300 mL Erlenmeyer flask containing small glass beads and 99 mL of sterile normal saline, and culture it on a shaker at 28 °C for 1 h.

[0046] Take 1 mL of the suspension, dilute it successively by the 10-fold gradient dilution method, and take 100 μL of the 10-6, 10-7, and 10-8 dilutions and spread them on the 1 / 2LB medium, and culture it upside down at 30 °C.

[0047] On the second and third days, pick single colonies into the conventional LB medium, perform three streaking purifications, and select a strain that can tolerate alkaline and high-salt environments, named HRKJ-6, and preserve the obtained strain with 20% glycerol.

[0048] Example 2

[0049] Strain identification

[0050] (1) Identification of strain morphological characteristics

[0051] Streak HRKJ-6 onto the conventional LB medium and culture it statically at 30 °C. Single colonies grow after 24 hours. As Figure 1 shown, the colonies are round, creamy yellow, with neat edges, and the colony surface is moist, smooth, and without wrinkles. After culturing for 48 hours, the colony color changes from creamy yellow to creamy pink, and the surface is smooth.

[0052] (2) Molecular identification

[0053] PCR amplify 16S rDNA using universal primers:

[0054] 27F: 5'-AGAGTTTGATCCTGGCTCAG-3';

[0055] 1492R: 5'-GGTTACCTTGTTACGACTT-3'.

[0056] The amplified fragment size is about 1473 bp.

[0057] The reaction system is: 10×Buffer 2 μL, 2.5 mM dNTP, 1.5 μL, Primer1 1 μL, Primer2 1 μL, template 1 μL, enzyme 0.3 μL, water 13.2 μL, with a total volume of 20 μL;

[0058] The PCR reaction program is: 95 °C for 5 min; 95 °C for 30 s, 56 °C for 90 s, 72 °C for 60 s (33 cycles); 72 °C for 10 min; 4 °C.

[0059] After purifying and sequencing the amplified sequence, send it to the company for sequencing.

[0060] The 16S rDNA sequence of this bacterium (SEQ ID No.1) was obtained by forward and reverse splicing followed by sequencing. The sequence was subjected to homology comparison using the Blastn program of NCBI. The comparison results showed that the highest homology was with Halomonas bachuensis, reaching 99.28%. Combining the morphological characteristics of the strain, the strain was named Halomonas bachuensis HRKJ-6.

[0061] Halomonas bachuensis HRKJ-6 was deposited on December 10, 2024 at the General Microbiological Center of the China National Culture Collection Center (CGMCC), located at No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing. The deposit number is CGMCC No. 33015.

[0062] Example 3

[0063] Detect the effect of pH value on strain HRKJ-6

[0064] Prepare LB media with pH values of 4.5, 5, 6, 7, 8, 9, 10, and 10.5 respectively.

[0065] Pick a single colony of strain HRKJ-6 into a conventional LB medium and culture it overnight in a shaker at 30°C to obtain a suspension. After diluting the suspension tenfold, pipette 10 μL and spot-inoculate it on LB petri dishes with different pH values, and incubate it upright at 30°C. Observe the results after 60 hours.

[0066] The experimental results are as Figure 2 shown. Strain HRKJ-6 can remain viable within a wide range of pH values from 4.5 to 10.5, demonstrating excellent broad-spectrum pH tolerance, verifying the stability and persistence of strain HRKJ-6 in extreme acid-base environments.

[0067] Further observation found that although HRKJ-6 can survive under extreme acidic (pH 4.5) and strong alkaline (pH 10.5) conditions, its growth is relatively limited in these two extreme environments. Comprehensive analysis shows that HRKJ-6 shows a more ideal growth state in neutral to weakly alkaline environments (pH 7-10). Within this range, the growth rate of the strain is relatively fast. At the same time, under non-optimal growth conditions (such as pH 4.5 or pH 10.5), HRKJ-6 can still survive for a long time, which provides an important guarantee for its application in complex and changeable actual scenarios.

[0068] Example 4

[0069] Detect the effect of salt concentration on strain HRKJ-6

[0070] Prepare LB media with NaCl concentrations of 5%, 10% and 15% respectively.

[0071] Pick a single colony of HRKJ-6 strain and transfer it to a conventional LB medium. Incubate it overnight in a shaker at 30 °C to obtain a suspension. After diluting the suspension tenfold, pipette 10 μL and spot-inoculate it onto LB plates with different NaCl concentrations. Incubate it upright at 30 °C and observe the results after 60 hours.

[0072] As Figure 3 shown, the HRKJ-6 strain can still survive after being cultured in LB media with 5%, 10% and 15% NaCl concentrations for 60 hours, demonstrating its strong adaptability to high-salt environments. This characteristic indicates that the HRKJ-6 strain has great survival potential in saline-alkali soils or high-salt stress environments, providing an important basis for its applications in fields such as saline soil improvement, promoting the growth of salt-tolerant crops, and developing microbial resources in extreme environments.

[0073] Further observation of the experimental data reveals that although HRKJ-6 can still survive in a high-salt environment with 15% NaCl, its survival ability and growth status are significantly reduced compared to the conditions of 5% and 10% NaCl. This shows that although HRKJ-6 has strong salt tolerance, its optimal tolerance range may be more inclined to medium and low salt concentrations (such as 5%-10% NaCl).

[0074] Example 5

[0075] Prepare a fermentation inoculant of HRKJ-6 strain

[0076] Prepare an LB liquid medium (formula: tryptone 10 g / L, yeast extract 5 g / L, sodium chloride 10 g / L). Dispense the prepared medium into sterilized bottles and sterilize it at 121 °C under high-pressure steam for 20 minutes, then cool it for standby.

[0077] Select single colonies with uniform morphology and good growth from freshly streaked and purified plates, and pick the single colonies;

[0078] Inoculate the picked single colonies into a 250 mL sterilized Erlenmeyer flask containing 50 mL of LB liquid medium, and place it in a constant-temperature shaker for cultivation. The cultivation conditions are 30 °C and 200 rpm, and the cultivation time is 16 hours.

[0079] After the preparation of the seed liquid is completed, use a spectrophotometer to measure the OD 600 value of the seed liquid. After determining that the OD value is between 0.8 and 1.2, proceed with the subsequent fermentation.

[0080] Dispense the LB liquid medium into fermentation Erlenmeyer flasks (1 L), sterilize it at 121 °C under high-pressure steam for 20 minutes, and then cool it for standby.

[0081] Inoculate the prepared seed liquid into the fermentation medium at an inoculation amount of 5% (i.e., inoculate 5 mL of the seed liquid into every 100 mL of the fermentation medium).

[0082] The inoculated fermentation Erlenmeyer flask is placed in a constant temperature shaker for cultivation under the conditions of 30 °C and 200 rpm, and the cultivation time is 48 hours.

[0083] After 48 hours of fermentation cultivation, centrifuge at 4000 rpm for 10 minutes, collect the thalli, and adjust to a fermentation broth with a viable bacteria concentration of 1×10 8 CFU / mL using sterile normal saline.

[0084] Example 6

[0085] Detect the antibacterial activity of HRKJ-6 strain against different strawberry pathogenic bacteria

[0086] Experimental group: Spread 100 μL of the fermentation broth obtained in Example 5 evenly on the surface of the PDA plate to ensure uniform distribution of the broth;

[0087] Control group: Similarly, use a sterile pipette to aspirate 100 μL of sterile water and spread it evenly on the surface of the PDA plate;

[0088] Place the spread PDA plate in a laminar flow hood and let it stand for 15 minutes to allow the liquid to be completely absorbed and dried.

[0089] Use a sterilized puncher to cut out a bacterial block with a diameter of 8 mm from a freshly cultured pathogenic bacteria plate, ensuring that each bacterial block is of the same size and has a neat edge. The pathogenic bacteria selected in the present invention (isolated and cultured by our company) are as follows:

[0090] Rhizoctonia solani of strawberry, Fusarium oxysporum of strawberry, Colletotrichum gloeosporioides of strawberry, Botrytis cinerea of strawberry;

[0091] Inoculate the prepared pathogenic bacteria blocks at the central position of the PDA plate in the experimental group, and gently press to make them fully contact with the surface of the medium. Set 3 replicates for each pathogenic bacteria.

[0092] Invert the inoculated plate and place it in a constant temperature incubator for cultivation at 28 °C for 7 days.

[0093] After the cultivation is completed, use a vernier caliper to measure the diameter of the pathogenic bacteria colonies, and calculate the colony expansion diameter and antibacterial rate.

[0094] Antibacterial rate (%) = [(colony expansion diameter of the control group - colony expansion diameter of the experimental group) / colony expansion diameter of the control group] × 100%.

[0095] Table 1 Antibacterial activity of HRKJ-6 strain against different strawberry pathogenic bacteria

[0096]

[0097]

[0098] From Table 1 and Figure 4 the results show that the HRKJ-6 strain obtained by the present invention has a certain inhibitory effect on the pathogenic bacteria causing strawberry damping-off, strawberry root rot, strawberry anthracnose and strawberry gray mold, including Rhizoctonia solani, Fusarium oxysporum, Colletotrichum gloeosporioides and Botrytis cinerea of strawberries, indicating that the HRKJ-6 strain has a broad-spectrum effect against plant fungi.

[0099] Further observation reveals that there are significant differences in the antibacterial effects of the HRKJ-6 strain. Among them, the HRKJ-6 strain shows an extremely strong inhibitory effect on Fusarium oxysporum of strawberries, a strong inhibitory effect on Rhizoctonia solani of strawberries, a medium inhibitory effect on Colletotrichum gloeosporioides of strawberries, and a relatively weak inhibitory effect on Botrytis cinerea of strawberries.

[0100] In summary, the antibacterial characteristics of the HRKJ-6 strain show its broad application prospects in the field of crop disease control. It has important value especially in the biological control field of strawberry root rot.

[0101] Example 7

[0102] Detect the control effect of fermentation broth of HRKJ-6 strain with different concentrations on strawberry root rot

[0103] The fermentation broth of the HRKJ-6 strain was prepared into fermentation broth of 0.1×10 8 CFU / mL, 0.5×10 8 CFU / mL and 1×10 8 CFU / mL.

[0104] Take the soil in the greenhouse, remove the hard lumps and stones, then sterilize the soil by high-pressure steam at 121 °C for 30 minutes, dry it and put it into pots, and add water to make it moist for standby.

[0105] In each pot, transplant a strawberry plant seedling of the same size (variety is Hongyan), and carry out conventional water and fertilizer management.

[0106] Seven days after strawberry transplantation, use the root-injuring method to inoculate 10 mL of the original solution of Fusarium oxysporum of strawberries. The control group is inoculated with 10 mL of sterile water at the same time. Experimental group a is inoculated with 10 mL of the fermentation broth of the HRKJ-6 strain (0.1×10 8 CFU / mL), and experimental group b is inoculated with 10 mL of the fermentation broth of the HRKJ-6 strain (0.5×10 8CFU / mL), Group c in the experimental group was inoculated with 10 mL of the fermentation broth of strain HRKJ-6 (1×10 8 CFU / mL), with 20 pots for each treatment.

[0107] After 30 days, 10 pots were randomly selected from each group, and the disease index of different treatments was statistically analyzed according to the following disease index grading:

[0108] Grade 0: The roots were not diseased; Grade 1: The incidence rate of roots ≤ 30%, and the leaves were normal; Grade 2: 30% < the incidence rate of roots ≤ 60%, and the leaves were normal; Grade 3: 60% < the incidence rate of roots ≤ 80%; the leaves turned yellow; Grade 4: The incidence rate of roots > 80%, and the leaves withered; Grade 5: The whole plant died, and the leaves were dry.

[0109] Meanwhile, the control effect of the strain was calculated.

[0110] Table 2 Control effect of fermentation broth of strain HRKJ-6 at different concentrations on strawberry root rot

[0111] Experimental grouping Disease index / % Control effect / % P value Control group 82.04±3.75 - - Experimental group a 53.55±2.35 34.73 ＜0.001 Experimental group b 29.63±2.14 63.89 ＜0.001 Experimental group c 9.08±1.84 88.93 ＜0.001

[0112] Combined with Table 2 and Figure 5 the results, it can be seen that fermentation broths of strain HRKJ-6 at different concentrations can all produce obvious control effects on strawberry root rot. Further observation shows that when the concentration is 0.1×10 8 CFU / mL, the control effect is relatively average, while when the concentration is 1×10 8 CFU / mL, it can significantly improve the control of strawberry root rot. Therefore, the fermentation broth of strain HRKJ-6 of the present invention can be used to prepare a drug for preventing and treating strawberry root rot to effectively reduce the occurrence of strawberry root rot.

[0113] Example 8

[0114] Since strain HRKJ-6 has excellent salt and alkali tolerance characteristics, the effect of its promoting the growth of alfalfa in saline-alkali environment was detected in this example.

[0115] Select moderately saline-alkali soil with pH 8.4 and electrical conductivity 4.62. After autoclaving at 121 °C for 30 minutes and drying, it was filled into pots and moistened with water for standby;

[0116] Select the seeds of Gongnong No. 1 alfalfa with general salt and alkali tolerance. After surface disinfection and germination promotion treatment, they were sown into the pots, with 30 seeds sown in each pot.

[0117] The treatments were carried out according to the following grouping:

[0118] Control group: 2 mL of sterile water was applied on the sowing day, the 10th day and the 20th day respectively;

[0119] Experimental group a: On the sowing day, on the 10th day, and on the 20th day, 2 mL of the fermentation broth of HRKJ-6 strain with a concentration of 0.1×10 8 CFU / mL was applied respectively;

[0120] Experimental group b: On the sowing day, on the 10th day, and on the 20th day, 2 mL of the fermentation broth of HRKJ-6 strain with a concentration of 1×10 8 CFU / mL was applied respectively;

[0121] The emergence experiment was carried out in an artificial climate chamber. The emergence conditions were a variable temperature of 15 / 25°C, 12 hours of darkness / 12 hours of light, and a light intensity of 54 μmol·m -2 ·s -1 , lasting for 6 days;

[0122] After the emergence ended, it was placed in a variable temperature of 25±2 / 20±2°C and a humidity of 30% and continued to be cultured until the 30th day ended, and the emergence rate and plant height were counted.

[0123] From Figure 6 and Figure 7 The experimental results show that compared with the control group without applying the fermentation broth of the strain (the emergence rate was 35.35% and the plant height was 0.83 cm), experimental group a (the emergence rate was 52.92% and the plant height was 1.35 cm) and experimental group b (the emergence rate was 80.29% and the plant height was 2.07 cm) both showed significant improvements in the emergence rate and plant height of alfalfa. Moreover, this promoting effect was further enhanced with the increase in the concentration of the fermentation broth of HRKJ-6 strain, showing an obvious dose-dependence. This result indicates that HRKJ-6 strain has a significant growth-promoting effect on the emergence and growth of alfalfa in moderately saline-alkali environments, demonstrating its great potential as a plant growth-promoting bacterium.

Claims

1. A strain of Halomonas, characterized in that: The strain name of the Halomonas is Halomonas bachuensis HRKJ-6, which has been deposited in the General Microbiology Center (CGMCC) of the China Microbiological Culture Collection Administration, located at No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing. The deposit date is December 10, 2024, and the deposit number is CGMCC No. 33015.

2. The Halomonas according to claim 1, characterized in that The 16S rDNA sequence of the Halomonas HRKJ-6 is shown in SEQ ID NO.

1.

3. Use of the fermentation agent of Halomonas as claimed in claim 1 in the preparation of a growth promoter for promoting the emergence rate and growth of plants in saline-alkali soil.

4. The use according to claim 3, characterized in that: The saline-alkali soil is moderate saline-alkali soil, the plant is alfalfa, and the concentration of Halomonas HRKJ-6 in the fermentation agent is greater than or equal to 0.1×10 8 CFU / mL.

5. The use according to claim 4, characterized in that: In the fermentation agent, the concentration of Halomonas HRKJ-6 is 0.1×10 8 CFU / mL to 1×10 8 CFU / mL.

6. A growth promoter for promoting the emergence rate and growth of plants in saline-alkali soil, characterized in that: The growth promoter includes a fermentation agent of Halomonas HRKJ-6 with a deposit number of CGMCC No.33015; In the fermentation agent, the concentration of Halomonas HRKJ-6 is greater than or equal to 0.1×10 8 CFU / mL.

7. The growth-promoting agent according to claim 6, characterized in that The saline-alkali soil is moderate saline-alkali soil; the plant is alfalfa; in the fermentation agent, the concentration of Halomonas HRKJ-6 is 0.1×10 8 CFU / mL to 1×10 8 CFU / mL.

8. A method for promoting the emergence rate and growth of alfalfa in saline-alkali soil, characterized in that: The method comprises the following steps: (1) After surface disinfection and germination treatment, alfalfa seeds are sown in saline-alkali soil; (2) Apply the fermentation agent of Halomonas HRKJ-6 with the deposit number of CGMCC No.33015 on the day of sowing; (3) Apply the Halomonas HRKJ-6 fermentation agent once every 10 days after sowing.

9. The method according to claim 8, characterized in that In the fermentation agent, the saline-alkali soil is moderate saline-alkali soil, and the concentration of the Halomonas HRKJ-6 is 0.1×10 8 CFU / mL to 1×10 8 CFU / mL.

10. The method according to claim 9, characterized in that The pH of the moderate saline-alkali soil is 8.4, and the conductivity of the moderate saline-alkali soil is 4.62 mS / cm; The alfalfa is Gongnong No. 1 alfalfa.

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