Streptomyces ZX181 and application thereof in plant drought resistance

Abstract

The invention relates to the technical field of microorganisms, in particular to streptomyces ZX181 and application thereof in plant drought resistance. The preservation number of the streptomyces sp. ZX181 is CGMCC (China General Microbiological Culture Collection Center) No.35647; tests prove that the strain can play an obvious role in promoting plant growth and can also obviously promote plant growth under drought stress, so that the strain has an application prospect in the aspects of improving plant stress resistance and the like.

Description

Technical Field

[0001] This invention relates to the field of microbial technology, specifically to Streptomyces ZX181 and its application in plant drought resistance. Background Technology

[0002] Drought is one of the major abiotic stress factors restricting global crop production. Under drought conditions, plants face a series of physiological damages, including water deficit, decreased photosynthetic efficiency, and accumulation of reactive oxygen species (ROS), leading to cell membrane structure damage, metabolic disorders, and even plant death, seriously threatening the stability of agricultural production. Traditional drought-resistant measures (such as irrigation and chemical regulation) have some effect, but they have limitations such as high cost and significant environmental risks. Therefore, developing green and sustainable drought-resistant technologies has become an important direction for agricultural research.

[0003] In recent years, the interaction mechanism between soil microorganisms and plants has attracted much attention. Soil microorganisms participate in key physiological processes such as nutrient transformation, hormone regulation, and stress response by establishing a symbiotic relationship with plant roots. This interaction not only enhances the plant's adaptability to environmental stress but also improves soil structure and fertility, forming a virtuous cycle of synergistic survival between plants and microorganisms, providing a natural bioregulatory pathway for improving plant stress resistance. Plant rhizosphere growth-promoting bacteria, as a key functional microbial group around plant roots, play an important role in enhancing plant stress resistance. They promote growth by secreting plant hormones such as auxins and cytokinins, synthesize siderophores to improve nutrient utilization, or induce the activity of plant antioxidant systems to alleviate stress damage. Among them, Streptomyces have attracted much attention due to their unique metabolic characteristics. This group can produce abundant bioactive secondary metabolites, including antibacterial substances, siderophores, and growth regulators, which can effectively regulate plant physiological metabolism and enhance its drought resistance.

[0004] Therefore, discovering Streptomyces that can improve crop drought resistance has practical application value for the sustainable development of ecological agriculture and animal husbandry in arid and semi-arid regions. Summary of the Invention

[0005] The purpose of this invention is to provide a Streptomyces sp. ZX181 that can promote plant growth and, in addition, reduce the impact of extreme environments on plants, especially in drought conditions, increase plant stress resistance.

[0006] In a first aspect, the present invention provides Streptomyces strain ZX181, with accession number CGMCC No. 35647.

[0007] The strain ZX181 was isolated from soil samples from arid and saline-alkali environments in Haixi Prefecture, Qinghai Province.

[0008] Secondly, this invention provides the application of Streptomyces ZX181 in promoting plant growth.

[0009] In this invention, the Streptomyces ZX181 can promote seed germination and / or the growth of one or more of the following: roots, stems, leaves, or flowers and fruits. For example, it can promote or inhibit root length, stem diameter, plant height, leaf width, leaf length, number of leaves, leaf area, biomass, relative water content, chlorophyll content, yield, photosynthesis, etc.

[0010] In a third aspect, the present invention provides the application of Streptomyces ZX181 in regulating plant stress resistance.

[0011] Plant stress resistance refers to certain traits that enable plants to resist adverse environments, such as cold resistance, drought resistance, salt and alkali resistance, and high temperature resistance.

[0012] In this invention, the stress resistance includes, but is not limited to, resistance to salinity and alkalinity, resistance to cold, resistance to drought, and resistance to high temperatures.

[0013] In some specific embodiments of the present invention, the stress resistance is drought resistance.

[0014] In this invention, Streptomyces ZX181 can regulate the activity of antioxidant enzymes and the level of osmotic regulators to reduce oxidative damage and osmotic disturbances caused by drought stress, thereby alleviating drought stress damage to plants.

[0015] In this invention, when used, a single agent of Streptomyces ZX181 or an agricultural product made from it is used to treat seeds, spray on leaves, or drench roots.

[0016] In this invention, the plants include those used in agriculture and animal husbandry.

[0017] In some embodiments of the present invention, the plant is selected from grasses, legumes, asteraceae, chenopodiaceae, sedges, polygonum, or cruciferous grasses.

[0018] In some specific embodiments of the present invention, Streptomyces ZX181 is used to promote the growth of forage plants, particularly for highland forage.

[0019] Fourthly, the present invention provides a microbial preparation containing the aforementioned Streptomyces ZX181.

[0020] The beneficial effects of this invention are:

[0021] (1) The Streptomyces ZX181 provided by the present invention can effectively promote the germination of plant seeds and the growth of organs such as roots, stems and leaves, improve biomass and photosynthetic efficiency, and can maintain the normal growth and development of plants, especially under drought stress.

[0022] (2) The Streptomyces ZX181 provided by the present invention significantly reduces oxidative damage and osmotic imbalance caused by drought stress by regulating the activity of antioxidant enzymes (such as CAT, SOD, POD) and the level of osmotic regulators (such as proline, soluble sugars), thereby improving the salt tolerance of plants.

[0023] (3) Streptomyces ZX181 has growth-promoting and stress-resistant effects on a variety of forage grasses such as grass and legume, and has a wide range of applications.

[0024] The following abbreviations have the following meanings:

[0025] MDA stands for malondialdehyde;

[0026] SOD stands for superoxide dismutase.

[0027] POD stands for peroxidase;

[0028] CAT stands for catalase. Attached Figure Description

[0029] Figure 1 Morphological observation of strain ZX181 (A: morphological characteristics in culture; B: microscopic observation (100×)).

[0030] Figure 2 Test of the iron-carrier production capacity of ZX181;

[0031] Figure 3 Effects of Streptomyces ZX181 on the growth of red clover seedlings under drought stress;

[0032] Figure 4 Effects of Streptomyces ZX181 on the phenotypic and physiological parameters of *Lysimachia foenum-graecum* seedlings under drought stress (A: leaf area; B: plant height; C: root length; D: biomass; E: chlorophyll content; F: maximum photochemical efficiency Fv / Fm; G: relative water content; H: relative electrical conductivity; different lowercase letters indicate the significance level p<0.05).

[0033] Figure 5 Effects of Streptomyces ZX181 on peroxide content, antioxidant and osmotic regulation levels in *Lysimachia foenum-graecum* seedlings (A: hydrogen peroxide content; B: malondialdehyde content; C: superoxide dismutase activity; D: peroxidase activity; E: catalase activity; F: glutathione content; G: soluble sugar content; H: proline content; different lowercase letters indicate the significance level p<0.05). Detailed Implementation

[0034] To enable those skilled in the art to better understand the present invention, the invention will be further described in detail below with reference to specific embodiments. It should be understood by those skilled in the art that this should not be construed as limiting the scope of the claims of the present invention. Unless otherwise defined, the technical and scientific terms used in the following embodiments have the same meaning as commonly understood by those skilled in the art. It should also be noted that, unless otherwise specified, the reagents or instruments used in the present invention are all conventional biochemical reagents or instruments, which can be purchased commercially.

[0035] Example 1

[0036] 1 Experimental Methods

[0037] 1.1 Experimental strains

[0038] Streptomyces sp. ZX181 was isolated from soil samples from an arid and saline-alkali environment in Haixi Prefecture, Qinghai Province. This strain was deposited on August 15, 2025, at the China General Microbiological Culture Collection Center (CGMCC, address: No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences, 100101, China), with accession number CGMCC No. 35647.

[0039] 1.2 Observation and identification of microbial morphology

[0040] The bacterial seed culture was streaked on MS solid medium (20.0 g soybean meal, 20.0 g mannitol, 20.0 g agar dissolved in 1 L tap water, pH 7.0), and the morphological characteristics of the colonies were observed and recorded. These characteristics included color, shape, colony size, transparency, gloss, texture, colony edge features, and ridge shape. The mycelial morphology was observed under an optical microscope using Gram staining.

[0041] 1.3 Determination of growth-promoting characteristics of strain ZX181

[0042] 1.3.1 Determination of Ferrocarrier Generation Capacity

[0043] The ZX181 strain was activated by inoculating 1% (v / v) into 3 mL of tryptone soybean broth (TSB) liquid medium and incubating at 28°C (180 rpm) for 48 h. Then, it was inoculated into Chromium Azurite S (CAS) detection medium and incubated at 28°C for 72 h. The appearance of an orange-yellow halo around the colony indicated siderophore production. The siderophore production capacity was then assessed by measuring the diameter of the clear halo (D) of a single colony and the colony diameter (d), using the D / d ratio.

[0044] 1.3.2 Assay for Auxin (IAA) Production Capacity

[0045] The ability of the strain to secrete indoleacetic acid (IAA) was determined by colorimetric assay. The test strain was inoculated with a solution containing 100 mg·L⁻¹ of [a specific solution]. -1 Tryptophan was cultured in TSB medium at 28°C with shaking for 48 h. 2 mL of the supernatant after centrifugation was taken, and 50 μL of 83% phosphate and 4 mL of Salkowski's reagent were added for reaction. If the solution turned pink, it indicated the presence of IAA. For IAA content determination, an IAA standard curve was first established. 10 mg of IAA was accurately weighed, dissolved in anhydrous ethanol, and diluted to 100 mL to prepare a 100 μg / mL solution. -1 The stock solution was diluted sequentially to 20, 40, 60, 80, and 100 μg·mL. -1 The standard solution was prepared. 2 mL of the standard solution and 2 mL of Salkowski colorimetric solution were mixed and reacted in the dark for 30 min, followed by a measurement of the A530 value. A standard curve was established with absorbance as the independent variable and IAA concentration as the dependent variable to calculate the IAA content in the sample.

[0046] 1.3.3 Determination of Extracellular Polysaccharide (EPS) Production Capacity

[0047] The bacterial culture medium of the strain, cultured for 48 hours, was diluted with an equal volume of deionized water, and centrifuged at 8000 rpm for 15 min to remove bacterial cells. The supernatant was collected, and two volumes of 95% ethanol were added. After mixing, the mixture was centrifuged again under the same conditions. The resulting precipitate was the crude polysaccharide, and its content was determined using the phenol-sulfuric acid method. Standard curve establishment: 20 mg of glucose was accurately weighed and diluted to 500 ml. A series of gradients were prepared: 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, and 1.8 ml of glucose solution. Distilled water was added to bring the volume to 2.0 ml. 1.0 ml of 6% phenol and 5.0 ml of concentrated sulfuric acid were added, and the mixture was allowed to stand for 30 minutes before measuring the absorbance at 490 nm. A standard curve was constructed using glucose content (μg) as the independent variable. 1.0 ml of the sample was taken, and 1.0 ml of distilled water was added. The colorimetric determination was performed using the same method, and the polysaccharide content was calculated based on the standard curve.

[0048] 1.3.4 Determination of biofilm formation capacity

[0049] Quantitative assessment of in vitro biofilm formation was performed using a microtiter plate method. 100 μL of bacterial culture was inoculated into 96-well plates and incubated at 37°C for 36 h. After washing three times with PBS buffer, the plates were fixed with methanol for 15 min, air-dried, stained with crystal violet for 5 min, rinsed with running water to remove excess dye, dried, and then dissolved in 33% glacial acetic acid. The absorbance at 590 nm was measured. Uninoculated culture medium served as a negative control, with the threshold (Dc) set at twice the negative OD value. Based on the experimental results, the plates were classified according to the following criteria: OD 590 > 2Dc is determined to be a strong biofilm, Dc < OD 590 ≤2Dc indicates a weak biofilm, OD 590 If Dc ≤ , no biofilm will form.

[0050] 1.4 Amplification and Sequencing Based on 16S rRNA Gene Sequence

[0051] A 5% bacterial seed culture was cultured in TSB medium at 28 °C and 180 r / min for 3 days. The bacterial cells were collected by centrifugation at 4 °C and 6000 r / min for 10 min. After washing three times with sterile water, chelation resin was added, and the mixture was placed in a PCR instrument at 99 °C for 30 min to extract DNA. The mixture was then centrifuged at 4 °C and 12000 r / min for 5 min, and the supernatant was used as a PCR template. The 16S rRNA gene sequence was amplified using universal bacterial amplification primers 27F (5′-AGAGTTTGATCCTGGCTCAG-3′) and 1492R (5′-TACGGCTACCTTGTTACGACTT-3′). PCR reaction system (25 μL): 0.3 μL each of forward and reverse primers (10 μmol / L), 0.3 μL of high-fidelity PCR polymerase (0.05 U / μL), 2.5 μL of 10*Buffer, 2 μL of dNTPs, 1.5 μL of template (56 ng / μL), and 18.1 μL of sterile ddH2O. PCR reaction conditions: 95 ℃ for 5 min; 95 ℃ for 30 s, 59 ℃ for 30 s, 72 ℃ for 1 min, 35 cycles; 72 ℃ for 5 min. PCR products were detected by 1% agarose gel electrophoresis and then sequenced.

[0052] 1.5 Study on the growth-promoting effect of fungal agent ZX181 on *Agrostis pilosa* under drought stress

[0053] 1.5.1 Preparation of bacterial suspension

[0054] The bacterial strain was streaked onto MS medium and incubated at 28°C for 96 h. Single colonies were picked and incubated in TSB medium at 28°C and 180 rpm for 72 h. Cells were collected by centrifugation at 5000 rpm for 10 min, and then resuspended in sterile deionized water. The bacterial suspension was adjusted to 1.0 × 10⁻⁶. 8 CFU / mL was used for subsequent inoculation experiments on red bean grass seedlings.

[0055] 1.5.2 Potted plants and drought stress treatment

[0056] The potted plant used was *Ormosia henryi*, and the test soil was a 1:1:1 mixture of sand, peat moss, and vermiculite. Plump *Ormosia henryi* seeds were selected, soaked in 75% ethanol for 30 seconds, rinsed five times with sterile water, then disinfected with 10% sodium hypochlorite for 5 minutes, rinsed five times with sterile water, and evenly sown in flowerpots with nine seedlings per pot. The seedlings were then cultured in an artificial climate chamber under the following conditions: 16 h light / 8 h darkness, 24°C, and a light intensity of 8000 LUX. After 21 days of culture, drought and inoculation treatments were applied. Four groups were set up for the pot experiment: the uninoculated and normally watered group (NC), the normally watered group inoculated with ZX181 (NC+ZX181), the drought stress group (DR), and the drought stress group inoculated with ZX181 (DR+ZX181). The NC and NC+ZX181 groups were watered every three days, while the DR and DR+ZX181 groups were not watered for 14 days. The inoculation treatment was performed by root irrigation, with 5 mL of bacterial suspension being applied to the rhizosphere of the plants in the NC+ZX181 and DR+ZX181 treatment groups for three consecutive days. The drought stress group (DR) was treated with an equal volume of distilled water instead of bacterial suspension. After 14 days of drought treatment, plant phenotypes were photographed and observed, and plant tissues were collected to determine relevant physiological and biochemical indicators.

[0057] 1.5.3 Measurement of physiological and biochemical indicators

[0058] Plant growth indicators were measured as follows: plant height and root length were measured with a tape measure, biomass was measured with an electronic balance, and leaf area was measured using ImageJ software. Five replicates were performed for each indicator.

[0059] Relative water content of leaves (RWC): 0.2 g of unfolded leaves of the same plant height were selected, blanched in an oven at 105℃ for 15 minutes, and dried at 80℃ to constant weight. The leaves were weighed and the relative water content was calculated according to the following formula: relative water content (%) = (FW-DW) / (TW-DW)×100, where FW, TW and DW represent fresh weight, saturated fresh weight and dry weight, respectively.

[0060] Chlorophyll fluorescence: Chlorophyll fluorescence index of the same tissue part of plants in different treatment groups was measured using a chlorophyll fluorescence meter (FluorPen FP110, Czech Photonic Systems Instruments Co., Ltd.). The maximum photochemical efficiency (Fv / Fm) was measured after the samples were dark adapted for 30 min.

[0061] Chlorophyll content: The relative chlorophyll content of the leaves was determined by measuring the difference in optical density at two wavelengths (650 nm and 940 nm) in the same tissue of the plants under different treatments using a chlorophyll meter (SPAD-502Plus, Konica Minolta, Japan).

[0062] Relative electrical conductivity (REC) of leaves: Weigh 0.5 g of plant leaves and place them in a 50 mL centrifuge tube. Add 30 mL of ultrapure water and shake at room temperature for 3 h. Then, measure the relative electrical conductivity of the plant seedlings using a conductivity meter. Next, boil the leaves for 15 min and, after cooling to room temperature, measure the conductivity again after boiling. The formula for calculating the conductivity is: Relative electrical conductivity of leaves = (Conductivity before boiling / Conductivity after boiling) * 100%.

[0063] Other biochemical indicators were determined: 0.1 g of fresh leaf samples from *Eriocaulon buergerianum* seedlings were collected, first ground with liquid nitrogen, and then the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), as well as the contents of soluble sugars, proline, malondialdehyde (MDA), hydrogen peroxide (H2O2), and glutathione (GSH) were determined according to the instructions using a biochemical reagent kit (purchased from Suzhou Keming Biotechnology Co., Ltd.). Three biological replicates were performed for each indicator. All data are expressed as mean ± standard error (mean ± SEM). One-way ANOVA was used to test for differences between groups. When ANOVA showed a significant difference (p < 0.05), Tukey's HSD test was used for multiple comparison analysis.

[0064] 2 Results Analysis

[0065] 2.1 Amplification and sequencing of the 16S rRNA gene of strain ZX181

[0066] A 1400 bp sequence was obtained by amplifying and sequencing the 16S rRNA gene of strain ZX181 (SEQ ID NO:1).

[0067] 2.2 Morphological analysis of strain ZX181

[0068] Morphological observation of strain ZX181 grown on MS medium revealed that the strain grew well on the medium, with white, dry, opaque colonies with relatively neat edges, and were round or oval in shape. Figure 1 The colony morphology of the strain ZX181 was consistent with that of Streptomyces. Single colonies were picked from the culture medium and subjected to Gram staining and microscopic observation. The results showed that strain ZX181 stained purple, indicating it was a Gram-positive bacterium with distinct hyphae, further confirming that it belonged to the Streptomyces genus.

[0069] 2.3 Growth-promoting characteristics of Streptomyces ZX181

[0070] Strain ZX181 can form a distinct orange-yellow halo on CAS medium ( Figure 2 The D / d ratio was 1.85, indicating that this strain has a strong siderophore-producing capacity. Furthermore, strain ZX181 can produce IAA and EPS, with contents of 4.011 μg·mL⁻¹, respectively. -1 and 0.816 mg·mL -1 Furthermore, it exhibits strong biofilm formation ability, with a Dc value of 0.232. These results indicate that Streptomyces ZX181 possesses strong potential plant growth-promoting properties.

[0071] 2.4 Effects of Streptomyces ZX181 on the growth promotion of *Sedum aizoon* and its enhancement of drought resistance.

[0072] (1) Streptomyces ZX181 has the effects of promoting plant growth and alleviating plant drought stress.

[0073] like Figure 3 As shown, compared to the drought stress group (DR group), ZX181 significantly promoted the plant growth and root development of *Alopecurus aequalis*. Plants inoculated with the fungicide exhibited superior growth and development under both drought and normal water supply conditions. The inoculated seedlings produced significantly more tillers than the DR group, and their underground root systems were more developed. These results indicate that ZX181 possesses typical plant growth-promoting characteristics and can significantly promote the growth and development of *Alopecurus aequalis* under drought stress.

[0074] (2) Effects of Streptomyces ZX181 on plant growth and physiological functions under drought stress

[0075] like Figure 4As shown in the AD diagram, under drought stress, the leaf area, plant height, root length, and biomass of *Lysimachia foenum-graecum* seedlings all decreased significantly. Inoculation with *Streptomyces* ZX181 significantly improved the growth phenotype and physiological condition of *Lysimachia foenum-graecum*. Under normal water conditions, compared with the NC group, inoculation with ZX181 (NC+ZX181 group) increased seedling height and root length by 4.24% and 6.17%, respectively, leaf area by 13.21%, and biomass by 31.96%. Compared with the drought stress group (DR), inoculation with ZX181 (DR+ZX181 group) significantly increased the plant height, root length, leaf area, and biomass of *Lysimachia foenum-graecum* seedlings, by 13.81%, 80.17%, 194.39%, and 72.90%, respectively.

[0076] Under drought conditions, seedlings inoculated with growth-promoting bacteria showed greener leaves. Compared to the DR group, the chlorophyll content of *Hedysarum heterotropoides* inoculated with ZX181 increased by 45.18%, while the maximum photochemical efficiency (Fv / Fm) significantly increased by 30.62%. Furthermore, ZX181 inoculation significantly improved the plant's water status, increasing the relative water content of *Hedysarum heterotropoides* by 35.13%. Drought stress damages cell membrane structure, leading to increased conductivity; after inoculation, plant cell integrity was significantly restored, with the relative conductivity of *Hedysarum heterotropoides* decreasing by 23.42% compared to the DR group. Compared to the NC group seedlings, ZX181 inoculation increased chlorophyll content, maximum photochemical efficiency, and relative water content by 10.77%, 7.00%, and 11.08%, respectively, while decreasing relative conductivity by 3.75%. Figure 4 EH). Pot experiments confirmed that Streptomyces ZX181 has a strong ability to improve plant growth and drought resistance.

[0077] (3) Effects of Streptomyces ZX181 on peroxide levels, antioxidant enzyme activity and osmotic regulation substance content

[0078] like Figure 5 As shown, drought stress leads to the accumulation of peroxides such as hydrogen peroxide (H2O2) and malondialdehyde (MDA). Figure 5 (A, B) may lead to severe oxidative stress in seedlings; however, inoculation with Streptomyces ZX181 significantly reduced the accumulation of these oxygen metabolites. Compared with the DR group, the H2O2 and MDA contents of seedlings inoculated with ZX181 decreased by 28.28% and 19.41%, respectively; under normal moisture conditions, compared with uninoculated NC, the H2O2 content of *Lysimachia nummularia* seedlings inoculated with ZX181 decreased by 52.36%, and the MDA content decreased by 25.29%. Figure 5 (A, B). The above indicates that the fungal agent ZX181 can effectively alleviate drought stress-induced oxidative damage, and by reducing the accumulation of lipid peroxidation products, it maintains the integrity and functional stability of the cell membrane, providing a potential protective mechanism for the growth of *Gnaphalium affine* under drought conditions.

[0079] Drought stress induced the accumulation of peroxides, further activating the activity of antioxidant enzymes in *Agrostis pilosa*. Under normal moisture conditions, compared with the uninoculated NC group, seedlings inoculated with ZX181 showed increased activities of antioxidant enzymes such as SOD, POD, and CAT by 45.18%, 16.43%, and 398.88%, respectively; under drought stress conditions, inoculation with ZX181 increased the activities of SOD, POD, and CAT by 29.03%, 52.32%, and 22.44%, respectively. Figure 5 CE). Furthermore, compared to the NC and DR treatment groups, the content of the non-enzymatic antioxidant GSH in seedlings of the inoculated groups NC+ZX181 and DR+ZX181 was significantly increased, by 83.68% and 22.05%, respectively. Figure 5 F). These results indicate that drought stress activates the plant's antioxidant defense system, increasing the enzymatic and non-enzymatic antioxidant activity of *Lysimachia foenum-graecum* seedlings and aggravating membrane lipid damage, thereby alleviating oxidative damage caused by drought stress. Soluble sugars and proline, osmotic regulators, play important roles in regulating cell osmotic pressure under drought stress. Compared to the NC group, drought stress significantly induced the accumulation of soluble sugars and proline in *Lysimachia foenum-graecum* seedlings. Under normal water conditions, compared with the NC group without inoculation, inoculation with *Streptomyces ZX181* increased the contents of soluble sugars and proline by 16.97% and 64.42%, respectively; under drought stress, inoculation increased the contents of soluble sugars and proline by 11.90% and 82.57%, respectively. Figure 5 G, H).

[0080] The above results indicate that Streptomyces ZX181 can effectively promote the biosynthesis and accumulation of osmotic regulators, especially proline, in *Ormosia henryi* seedlings under drought stress, thereby enhancing their osmotic regulation capacity. This mechanism helps maintain intracellular water balance, mitigates drought-induced damage to cell structure, and thus improves the plant's drought resistance.

[0081] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the accompanying drawings are merely examples and do not limit the present invention. The objectives of the present invention have been fully and effectively achieved. The functions and structural principles of the present invention have been demonstrated and explained in the embodiments, and any variations or modifications may be made to the implementation of the present invention without departing from the stated principles.

Claims

1. Streptomyces strain ZX181, characterized in that, The accession number is: CGMCC No. 35647.

2. The application of Streptomyces ZX181 as described in claim 1 in promoting plant growth.

3. The application according to claim 2, characterized in that, The Streptomyces ZX181 can promote seed germination and / or the growth of one or more of the roots, stems, leaves, or flowers and fruits.

4. The application of Streptomyces ZX181 as described in claim 1 in regulating plant stress resistance.

5. The application according to claim 4, characterized in that, The stress resistance is at least one of drought resistance, salinity resistance, cold resistance, and high temperature resistance.

6. The application according to claim 5, characterized in that, The aforementioned resistance refers to drought resistance.

7. The application according to claim 2 or 4, characterized in that, When using, treat seeds, spray leaves, or drench roots with a single agent of Streptomyces ZX181 or agricultural products made from it.

8. The application according to any one of claims 2-7, characterized in that, The plants mentioned include those used in agriculture and animal husbandry.

9. The application according to claim 8, characterized in that, The plants are selected from grasses, legumes, asteraceae, chenopodiaceae, sedges, polygonum, or cruciferous grasses.

10. A microbial preparation, characterized in that, Contains the Streptomyces ZX181 as described in claim 1.

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