Bacteria that promote plant recruitment of beneficial microbes and uses thereof

Abstract

The application belongs to the field of agricultural microorganism technology, and relates to a kind of bacteria for promoting plant recruitment of beneficial microorganisms and application thereof.The bacteria are Halomonas hydrossis Halomonas neptunia , which were preserved in China General Microbiological Culture Collection Center on May 11, 2026, with a preservation number of CGMCC NO.38626.The strain obtained in the application is isolated from the rhizosphere of reed growing at 119°20'17.80''E, 37°0'3.48''N, can promote the growth of wheat in natural saline-alkali soil, alleviate the harm of salt stress, increase the relative abundance of beneficial microorganisms in the rhizosphere of wheat, and thus be beneficial to improving the adaptability of wheat to salt-alkali stress.

Description

Technical Field

[0001] This invention belongs to the field of agricultural microbiology technology, and relates to a bacterium that promotes the recruitment of beneficial microorganisms by plants and its application. Background Technology

[0002] Saline-alkali soil is an important potential arable land resource, but its excessively high salt content makes it difficult for crops such as corn and wheat to grow normally. Improving the soil through various physical and biological methods, while also enhancing the crop's own salt tolerance, is an important way to increase the utilization rate of saline-alkali soil.

[0003] An increasing number of salt-tolerant plant growth-promoting rhizobacteria (ST-PGPRs) are being discovered in the rhizospheres of various plants in different habitats. ST-PGPRs mostly possess one or more growth-promoting properties, which can promote plant growth to a certain extent, even control pests and diseases, and increase crop yields, making them an important source of microbial inoculants. Simultaneously, the effective utilization of microbial inoculants can reduce the application of chemical fertilizers and improve soil quality, representing a highly efficient, low-cost, and sustainable remediation technology. However, the survival and successful colonization of microbial inoculants in the crop rhizosphere is one of the limiting factors for their development and utilization. The microbial composition in natural saline-alkali soils is complex and diverse, with a certain degree of competition between invasive species and native microorganisms. Reports on ST-PGPRs that enhance the ability of crops to recruit beneficial microorganisms are scarce. Summary of the Invention

[0004] This invention provides a bacterium that enhances the ability of wheat to recruit beneficial microorganisms and its application, so as to promote the recruitment of beneficial microorganisms by wheat and improve the growth of wheat in natural saline-alkali soil.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a bacterium that promotes the recruitment of beneficial microorganisms by plants, the bacterium being *Haloxylon ammodendron*. Halomonas neptunia It was deposited on May 11, 2026 at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC NO.38626.

[0006] Furthermore, the present invention provides a microbial inoculant containing the aforementioned Haloxylon ammodendron. Halomonas neptunia .

[0007] Preferably, the microbial agent contains *Haloxylon ammodendron*. Halomonas neptunia OD 600 The value is ≥0.4.

[0008] Furthermore, the present invention provides a method for preparing the microbial inoculant, wherein the *Haloxylon ammodendron* is used. Halomonas neptuniaMicrobial agents are obtained by culturing in a culture medium.

[0009] Preferably, in the preparation method, the culture temperature is 25-36℃ and the culture time is 16-18h; the culture process is accompanied by rotation, and the rotation speed is 120-150rpm.

[0010] Furthermore, the present invention provides the application of the bacteria in promoting plant growth and / or improving plant salt tolerance, wherein the bacteria promote plant growth and / or improve plant salt tolerance by promoting the recruitment of beneficial microorganisms by plants.

[0011] Preferably, the plant includes wheat.

[0012] Preferably, promoting plant growth includes improving one or more of the following indicators (1) to (4): (1) Fresh weight; (2) Superoxide dismutase activity; (3) Catalase activity; (4) Proline content.

[0013] Preferably, improving plant salt tolerance includes mitigating the damage of salt stress to plants and / or enhancing the plant's ability to tolerate salt stress.

[0014] Furthermore, the present invention provides a method for promoting plant growth and / or improving plant salt tolerance, comprising: applying a microbial agent containing the bacteria after the plant has sprouted.

[0015] The beneficial effects of this invention are: This invention provides a Haloxylon ammodendron bacterium. Halomonas neptunia The bacterium, with accession number CGMCC NO.38626, enhances the salt stress tolerance of plants, alleviates the damage caused by salt stress, promotes plant growth in saline-alkali land, and thus helps increase crop yields in saline-alkali areas. Experiments have demonstrated that this bacterium significantly increases the fresh weight and catalase activity of wheat under salt stress conditions and increases the number of beneficial bacteria in the wheat rhizosphere. Planococcus The abundance of these bacteria promotes wheat growth under salt stress and alleviates the damage caused by salt stress. The bacteria provided by this invention are beneficial for improving the salt stress tolerance of crops in saline-alkali land and for increasing crop yields in such land. Attached Figure Description

[0016] Figure 1 The *Haloxylon ammodendron* strain of the present invention Halomonas neptunia ( Halomonas Phylogenetic tree of B2); Figure 2 The *Haloxylon ammodendron* strain of the present inventionHalomonas neptunia ( Halomonas Colony morphology of B2); Figure 3 To study the effects of different salt concentrations on Haloxylon ammodendron Halomonas neptunia ( Halomonas B2) Effects on growth; Figure 4 This is a comparative diagram showing the effect of inoculation with the microbial agent of the present invention on wheat growth in natural saline-alkali soil; where CK is the control group, without any inoculation treatment, and group B2 is the inoculated strain. Halomonas B2 processing group; Figure 5 The effects of the microbial agent of the present invention on the fresh weight and antioxidant enzyme activity of wheat under different treatments; wherein, (a) fresh weight; (b) superoxide dismutase (SOD) activity; (c) proline (Pro) content; (d) catalase (CAT) activity; CK is the control group, without any inoculation treatment, and B2 is the inoculated strain. Halomonas B2 processing group; Figure 6 The beneficial bacteria genus in the rhizosphere of wheat after inoculation with the inoculant of the present invention ( Planococcus The impact of ). Detailed Implementation

[0017] To facilitate understanding of the present invention, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and specific examples. The following examples or drawings are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0018] Example 1: Isolation, Screening and Identification of Strains The inventors of this application collected rhizosphere soil samples from reeds in a saline-alkali area of ​​Dongying City, Shandong Province, and used a gradient dilution method to isolate and purify microorganisms. 10g of soil sample was weighed and placed in 100mL of sterile water. The sample was shaken at 150rpm and 30℃ for 20min to ensure thorough dispersion. Aseptically, 100μL of the supernatant was added to 900μL of sterile water and diluted with sterile water to prepare a 10 μL gradient dilution method. -2 -10 -5 Diluents of various concentrations were prepared. 100 μL of each diluent was spread onto LB agar plates containing 2% NaCl using the standard spread plate method. The plates were incubated at 30°C for 48 hours. After colonies grew on the plates, single colonies were picked and purified until no contaminating colonies were observed. One strain, designated B2, was selected and transferred to LB agar containing 2% NaCl for preservation and identification. The phylogenetic tree and colony morphology are shown in the appendix. Figure 1 Appendix Figure 2 .

[0019] Comparative analysis revealed that strain B2 was similar to the standard model strain. Halomonas neptunia Eplume1 is the most closely related species, with its 16S rDNA sequence (SEQ ID NO.1) showing 99.52% homology to this genus. A phylogenetic tree was constructed using the Neighbor-Joining method with MEGA X software, a commonly used tool in this field. Comparative analysis revealed that strain B2 is closely related to... Halomonas neptunia The Eplume1 cluster is on one branch with a confidence level of 67%.

[0020] The *Haloxylon ammodendron* strain provided in this embodiment of the invention Halomonas neptunia strain number is Halomonas B2 was deposited on May 11, 2026, at the China General Microbiological Culture Collection Center (CGMCC), Institute of Microbiology, Chinese Academy of Sciences, No. 3, Beichen West Road, Chaoyang District, Beijing, with accession number CGMCC NO.38626.

[0021] Example 2, strain Halomonas B2 Optimal Salinity Determination 100 μL of logarithmic-phase B2 bacterial culture was inoculated into liquid LB medium with NaCl concentrations of 0%, 1%, 2%, 5%, 8%, and 10%, respectively. The cultures were incubated at 30°C with shaking for 8 hours at 120 rpm. OD values ​​were then measured. 600 The effect of salinity on B2 growth is shown in the appendix. Figure 3 B2 has an optimal salt concentration of 2% NaCl and is a mildly halophilic bacterium.

[0022] Example 3, bacterial strain Halomonas Vitamin B2's effect on wheat growth Saline-alkali soil with a salt content of 1.35 g / kg was collected from Dongying area, air-dried and sieved, and then spring wheat (Jinchun No. 6) was sown. The soil was kept at about 70% field capacity, with natural temperature and light. Sowing was carried out on April 7, 2025, and harvesting was carried out on May 22, 2025. Each treatment was replicated in three groups, and a total of 5 inoculations were carried out. The OD value was about 0.3, and 50 mL was inoculated each time.

[0023] like Figure 4 and Figure 5 As shown, Halomonas Compared with the control group, the B2 treatment significantly promoted wheat growth, increasing fresh weight by 105%, and significantly improved CAT enzyme activity in the aboveground parts, while also showing some improvement in SOD activity. CAT activity was determined using a kit method, the main steps of which were extraction of crude enzyme solution and measurement of absorbance after terminating the reaction with ammonium molybdate. SOD activity was determined using a double-antibody sandwich method, where the homogenized sample, standards, and colorimetric reagent were added sequentially according to the kit instructions. After the reaction was completed, the absorbance value was measured, and the activity was calculated based on the mark.

[0024] Example 4, strain Halomonas Effects of B2 on wheat rhizosphere bacteria Based on the 16S diversity sequencing results of rhizosphere soil, the top 100 abundant ASVs (amplicon sequence variants) were selected for co-occurrence network analysis, as shown in the attached figure. Figure 6 As shown, compared with CK (blank control group), vaccination Halomonas B2 added high-abundance ASVs Planococcus The proportion of genera increased Planococcus Belonging to Halomonas The association of genera.

[0025] In this example, the rhizosphere soil comes from... Figure 4 The potted plant experiments shown are CK and B2 treatment groups.

[0026] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A bacterium that promotes the recruitment of beneficial microorganisms by plants, characterized in that: The bacterium is *Haloxylon ammodendron*. Halomonas neptunia It was deposited on May 11, 2026 at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC NO.38626.

2. A microbial inoculant, characterized in that, Bacteria that promote the recruitment of beneficial microorganisms by plants, as described in claim 1.

3. The microbial agent according to claim 2, characterized in that, The microbial agent contains Haloxylon ammodendron. Halomonas neptunia OD 600 The value is ≥0.

4.

4. A method for preparing the microbial inoculant according to claim 2 or 3, characterized in that: Halomonas tectorum Halomonas neptunia Microbial agents are obtained by culturing in a culture medium.

5. The preparation method according to claim 4, characterized in that, The culture temperature is 25–36℃, and the culture time is 16–18 h; the culture process is accompanied by rotation, and the rotation speed is 120–150 rpm.

6. The application of the bacteria according to claim 1 in promoting plant growth and / or improving plant salt tolerance, characterized in that: The bacteria promote plant growth and / or enhance plant salt tolerance by encouraging the recruitment of beneficial microorganisms by the plant.

7. The application according to claim 6, characterized in that, The plant mentioned includes wheat.

8. The application according to claim 6, characterized in that, The promotion of plant growth includes promoting the improvement of any one or more of the following indicators (1) to (4): (1) Fresh weight; (2) Superoxide dismutase activity; (3) Catalase activity; (4) Proline content.

9. The application according to claim 6, characterized in that, Improving plant salt tolerance includes mitigating the damage caused by salt stress to plants and / or enhancing their ability to tolerate salt stress.

10. A method for promoting plant growth and / or improving plant salt tolerance, characterized in that, include: After the plants germinate, apply a microbial inoculant containing the bacteria described in claim 1.

Images