Streptomyces oryzae, bacterial agents and their applications

Abstract

This invention relates to the field of microbial technology, disclosing a strain of *Streptomyces oryzae*, its inoculant, and its applications. The *Streptomyces oryzae* strain provided by this invention exhibits excellent abilities to degrade benzoic acid, solubilize organophosphates, secrete auxin (IAA), and possess broad-spectrum inhibition against various pathogens. Application of this strain and related preparations to the plant rhizosphere can effectively improve soil quality, control soil-borne diseases, and promote plant growth. Furthermore, since this bacterium originates from the Wuliang Mountain Nature Reserve in Yunnan Province and is a natural rhizosphere fungus, it possesses good colonization capabilities. Moreover, as it originates from virgin forest soil, it has a greater ability to adapt to complex environments than general strains, thus enabling it to control the occurrence and spread of soil-borne diseases and promote plant growth.

Description

Technical Field

[0001] The invention relates to the technical field of microorganisms, and in particular to a strain of Streptomyces oryzae, a bacterial agent and applications thereof. Background Art

[0002] With the development of modern agriculture towards large-scale, intensive and monoculture, continuous cropping is very common, resulting in frequent cropping problems such as crop growth inhibition, high incidence of soil-borne diseases and sharp decline in yield. The secretion of autotoxic substances by plant roots is one of the main factors leading to this phenomenon. With the development of society and economy, people are in urgent need of more green, environmentally friendly and sustainable ways to carry out agricultural production.

[0003] Beneficial rhizosphere microorganisms can provide plants with more available nutrients and effectively inhibit or even kill plant pathogens by solubilizing phosphorus, secreting plant hormones, and producing antibacterial active substances during their growth and metabolism. Beneficial rhizosphere microorganisms can also use self-toxic substances in the soil to reduce or eliminate the adverse effects of the accumulation of self-toxic substances on the soil or plants. Therefore, it has great application value and potential in the biological control of plant diseases. In addition, the application of beneficial rhizosphere microorganisms can reduce the use of pesticides and fertilizers, which can reduce production costs on the one hand, and meet the requirements of modern agriculture for sustainable development on the other hand, which is of great significance to the development and transformation of modern agricultural production.

[0004] However, the number of rhizosphere beneficial strains that can be used for actual production is still very limited, and the effects of existing strains need to be improved. Moreover, the development of most plant rhizosphere beneficial strains now relies on artificial mutagenesis and screening, and the obtained strains are prone to problems of being difficult to colonize or the effects far below the laboratory detection level in actual production. In order to meet the needs of agricultural production, it is urgent to develop new rhizosphere beneficial strains with better and more stable growth-promoting effects, which are easier to colonize and can be applied to actual production. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned problems existing in the prior art, and to provide a strain of Streptomyces oryzae, a bacterial agent and their applications. The Streptomyces oryzae provided by the present invention is a rhizosphere fungus collected from a primeval forest, has good colonization ability after application, and after testing, the strain can efficiently degrade benzoic acid, and has good auxin secretion and organic phosphorus decomposition ability, has a broad-spectrum antibacterial activity against a variety of pathogens and has a significant promoting effect on plant growth.

[0006] In order to achieve the above-mentioned object, the first aspect of the present invention provides a strain of Streptomyces oryzae, the deposit number of which is CCTCC NO:M 20231643.

[0007] The second aspect of the present invention provides a bacterial agent, wherein the bacterial agent comprises the Streptomyces oryzae described in the first aspect.

[0008] The third aspect of the present invention provides the use of the Streptomyces oryzae described in the first aspect, or the bacterial agent described in the second aspect, in degrading benzoic acid, solubilizing phosphate, secreting auxin, antagonizing pathogens or alleviating the inhibitory effect of benzoic acid on seed germination.

[0009] A fourth aspect of the present invention provides a method for preparing an auxin, the method comprising culturing the Streptomyces oryzae described in the first aspect, and collecting the culture product.

[0010] The fifth aspect of the present invention provides the use of the rice blastomyces described in the first aspect, or the bacterial agent described in the second aspect in improving soil, and / or promoting plant growth, and / or promoting plant seed germination, and / or preventing and controlling the occurrence of soil-borne diseases, and / or preventing and controlling the spread of soil-borne diseases.

[0011] The sixth aspect of the present invention provides a method for preventing and controlling soil-borne plant diseases and / or promoting plant growth, the method comprising applying the blastomyces oryzae and / or its metabolites described in the first aspect, or the bacterial agent described in the second aspect, to the rhizosphere soil of the plant.

[0012] Through the above technical solution, the present invention can at least achieve the following beneficial effects:

[0013] (1) The rice blast mycelium provided by the present invention has excellent effects of degrading benzoic acid and degrading organic phosphorus, and can also produce growth hormone. In addition, the bacteria can also have a broad-spectrum inhibitory effect on a variety of pathogens, can effectively improve soil quality, and increase the content of nutrients that can be used by plants in the soil, thereby having a good effect of promoting plant growth and preventing and controlling plant diseases.

[0014] (2) The rice blast mycelium provided by the present invention is a natural forest rhizosphere fungus isolated from the unique habitat of the original forest. Compared with the strains screened by laboratory mutagenesis, it has better adaptability to the planting environment and can better colonize in the soil, thereby more stably exerting the effect of promoting growth and preventing diseases. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is the colony morphology of strain YNK-FS0018 in Example 1.

[0016] Figure 2 It is the phylogenetic tree of strain YNK-FS0018 in Example 1.

[0017] Figure 3 This is a diagram showing the effect of strain YNK-FS0018 in Example 2 on degrading organic phosphorus.

[0018] Figure 4 This is a diagram showing the broad-spectrum antibacterial effect of strain YNK-FS0018 in Example 2.

[0019] Figure 5 This is a diagram showing the effect of strain YNK-FS0018 in Example 6 in alleviating the inhibition of seed germination by benzoic acid.

[0020] Biological Deposit

[0021] The rice blast mycin Streptomyces provided by the present invention is classified and named Streptomyces blastmyceticus YNK-FS0018, which has been preserved in the China Center for Type Culture Collection on September 7, 2023, with the address of No. 299, Bayi Road, Wuchang District, Wuhan City, Hubei Province, Wuhan University, and the preservation number is CCTCC NO: M 20231643. DETAILED DESCRIPTION

[0022] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0023] In the present invention, unless otherwise specified, "Streptomyces oryzae / strain CCTCC NO: M20231643", "Streptomyces oryzae / strain YNK-FS0018", "Streptomyces oryzae of the present invention (provided)" and the like all refer to the same strain, i.e., the Streptomyces oryzae strain with a deposit number of CCTCC NO: M20231643. The above expressions have the same meaning and can be used interchangeably.

[0024] In the present invention, "phosphorus solubilization" means that the P content available to plants in the soil is increased through the action of the strain provided by the present invention, for example, organic phosphorus components in the soil (such as lecithin, inositol hexaphosphate, etc.) are converted into a form that can be used by plants, thereby promoting the absorption and utilization of phosphorus in the soil by plants; for example, after continuous planting of crops such as tomatoes, tobacco, and cucumbers, phenolic acid self-toxic substances such as benzoic acid will be secreted. The accumulation of these phenolic acid self-toxic substances in the soil can easily cause problems such as germination and growth inhibition of crop seeds, which is not conducive to the continued planting of crops. "Benzoic acid degradation" means that the benzoic acid self-toxic substances secreted by plant roots can be degraded through the action of the strain provided by the present invention, thereby reducing or eliminating the adverse effects of the accumulation of self-toxic substances on the soil or plants.

[0025] The inventor of the present invention accidentally isolated a strain of Streptomyces oryzae from the rhizosphere soil of trees in Wuliangshan National Nature Reserve during the research process. It was found through testing that the strain has the functions of efficiently degrading benzoic acid, dissolving phosphorus, producing long hormones and antagonizing multiple pathogens. The strain can not only degrade phenolic acid autotoxic substances secreted by plant roots, but also convert organic phosphorus (such as lecithin, etc.) into effective phosphorus that can be absorbed by plants. After further research, the inventor also found that applying the fermentation liquid of the strain to the rhizosphere soil of plants can effectively promote plant growth, prevent and control the occurrence of tomato wilt, improve the soil environment, increase agricultural productivity, and promote the green and sustainable development of ecological agriculture.

[0026] Based on the above findings, the present invention provides a strain of Streptomyces blastmyceticus, the deposit number of which is CCTCC NO: M 20231643.

[0027] The second aspect of the present invention provides a bacterial agent, which comprises the Streptomyces oryzae described in the first aspect (as an active ingredient).

[0028] In the bacterial agent provided by the present invention, Streptomyces oryzae CCTCC NO: M20231643 can be used as the only active ingredient, or other strains can be added to form a common active ingredient.

[0029] The microbial agent provided by the present invention can be used for degrading benzoic acid, alleviating the inhibition of benzoic acid on the germination of crop seeds (preferably at least one of tomatoes, peppers and cucumbers), solubilizing phosphorus (especially organic phosphorus), preventing and controlling plant diseases caused by microbial infection, and producing auxins.

[0030] According to some preferred embodiments of the present invention, the microbial agent may also contain optional excipients. "Optional" means that in the microbial agent, the excipients can be added according to actual conditions and needs, and are not essential components of the microbial agent. The excipients may be any excipients that can be used for the preparation of microbial agents in the art, and may protect Streptomyces oryzae, improve the activity and survival rate of live bacteria in the microbial agent during long-term storage or transportation, and may include, for example, various culture media that can be used for the cultivation, storage and transportation of Streptomyces oryzae; microbial protective agents (such as freeze-drying protective agents, etc.); buffers, etc.

[0031] According to some preferred embodiments of the present invention, the bacterial agent may be a liquid bacterial agent.

[0032] In the present invention, there is no particular limitation on the content of Streptomyces oryzae CCTCC NO: M 20231643 in the bacterial agent, as long as the above-mentioned purpose can be achieved.

[0033] According to some preferred embodiments of the present invention, the content of Streptomyces oryzae in the bacterial agent is not less than 1×10 6 CFU / mL, preferably 1×10 7 -1×10 10 CFU / mL.

[0034] The third aspect of the present invention provides the use of the Streptomyces oryzae described in the first aspect, or the bacterial agent described in the second aspect, in degrading benzoic acid, solubilizing phosphate, secreting auxin, antagonizing pathogens or alleviating the inhibitory effect of benzoic acid on seed germination.

[0035] The present invention further provides a method for degrading benzoic acid, which comprises contacting benzoic acid with Streptomyces oryzae CCTCC NO: M 20231643.

[0036] According to some preferred embodiments of the present invention, the method may include evenly sprinkling Streptomyces oryzae CCTCC NO:M 20231643 (bacterial agent or culture solution) into the soil to alleviate the problem of benzoic acid accumulation caused by continuous cropping or soil pollution, thereby causing adverse effects on continued crop planting.

[0037] The present invention further provides a method for alleviating the inhibition of benzoic acid on crop seed germination, which comprises contacting the seeds with Streptomyces oryzae CCTCC NO: M 20231643 during the germination process.

[0038] According to a preferred embodiment of the present invention, the method may include:

[0039] i. Soak the seeds in water for 2-4 hours to obtain soaked seeds;

[0040] ii. contacting Streptomyces oryzae CCTCC NO: M 20231643 with the soaked seeds obtained in step i to obtain soaked seeds with alleviated germination inhibition.

[0041] Preferably, in step ii, the contacting method comprises immersing the soaked seeds in a culture solution of Streptomyces oryzae CCTCC NO:M 20231643. Preferably, the concentration of Streptomyces oryzae CCTCC NO:M 20231643 in the culture solution is 10 7 -10 8 CFU / mL (i.e., the content of Streptomyces oryzae in the culture medium reaches 10 7 -10 8 CFU / mL level, that is, the content of Streptomyces oryzae in the culture solution can be greater than or equal to 1×10 7 CFU / mL to less than 1×109 CFU / mL range).

[0042] Preferably, the method may further include:

[0043] iii. placing the soaked seeds with alleviated germination inhibition obtained in step ii under seed germination conditions to germinate them.

[0044] More preferably, step iii can be carried out by soaking the soaked seeds with relieved germination inhibition in water to make them germinate. Step iii can also be carried out by burying the soaked seeds with relieved germination inhibition in soil to make them germinate.

[0045] In the above method provided by the present invention, "immersion" refers to a process in which the seeds are contacted with water or a culture solution of Streptomyces oryzae CCTCC NO: M20231643, so that the seeds are in a moist state to promote seed germination. In order to prevent the seeds from germinating due to lack of oxygen, the "immersion" treatment can usually be performed by not completely immersing the seeds in the soaking liquid, or placing the seeds on a paper material such as absorbent paper, and then soaking the paper material with the soaking liquid.

[0046] According to a preferred embodiment of the present invention, the crop is at least one of tomato, pepper and cucumber.

[0047] A fourth aspect of the present invention provides a method for preparing an auxin, the method comprising culturing the Streptomyces oryzae described in the first aspect, and collecting the culture product.

[0048] Any method and conditions that can ferment and culture Streptomyces oryzae to produce auxin can be applied to the present invention.

[0049] According to a preferred embodiment of the present invention, the culture conditions include: culture temperature 28-32°C, culture time 72-96h.

[0050] According to a preferred embodiment of the present invention, when the fermentation culture is carried out in a shake flask fermentation manner, a shaking culture at a rotation speed of 100-200 rpm can be used during the fermentation process.

[0051] The fifth aspect of the present invention provides the use of the rice blastomyces described in the first aspect, or the bacterial agent described in the second aspect in improving soil, and / or promoting plant growth, and / or promoting plant seed germination, and / or preventing and controlling the occurrence of soil-borne diseases, and / or preventing and controlling the spread of soil-borne diseases.

[0052] In the present invention, "soil improvement" refers to increasing the content of nutrients in the soil that can be absorbed and utilized by plants, thereby improving soil quality and making the soil more suitable for plant growth. The soil quality can be determined by measuring the physical and chemical properties of the soil, such as the pH value of the soil, the content of nutrients, etc. The conversion of effective nutrients in the soil (i.e., nutrients that can be absorbed and utilized by plants, such as effective phosphorus, effective nitrogen, effective potassium, etc.) can also be determined by measuring the content of enzymes such as soil sucrose invertase, urease, acid phosphatase, and catalase in the soil, thereby determining the change in soil quality. Generally, the higher the content of nutrients in the soil, especially effective nutrients, the higher the content of the above enzymes in the soil, which means that the soil quality is better.

[0053] In the present invention, "promoting plant growth" refers to promoting the absorption of nutrients in the soil by plants and increasing the growth rate of plants, such as increasing the plant height, diameter, root length, plant weight, fruit weight and quality, etc., or shortening the plant growth cycle and promoting the growth and development of the plant root system.

[0054] In the present invention, "preventing and controlling the occurrence of soil-borne plant diseases" and "preventing and controlling the spread of soil-borne plant diseases" can be collectively referred to as "preventing and controlling soil-borne plant diseases". "Preventing and controlling soil-borne plant diseases" means having a control effect on soil-borne plant diseases (such as tomato wilt), which can significantly reduce the incidence of soil-borne plant diseases in fields where soil-borne plant diseases have occurred, avoid the occurrence of soil-borne plant diseases in fields where soil-borne plant diseases have not occurred, and ensure the healthy growth of plants. Usually, the control effect of soil-borne plant diseases can be tested by crop planting experiments.

[0055] According to some preferred embodiments of the present invention, the soil-borne plant diseases include diseases caused by at least one of tomato wilt pathogen (Fusarium oxysporum), corn leaf spot pathogen (Exserohilum turcicum), tobacco anthracnose pathogen (Colletotrichum micotianae), grass fruit stem spot pathogen (Phoma matteuciicola), tobacco black shank pathogen (Phytophthora parasitica) and banana wilt pathogen (Fusarium oxysporum fsp.Cubenserace4 (Foc4)).

[0056] Preferably, the soil-borne plant diseases include tomato wilt.

[0057] The present invention further provides a method for inhibiting plant pathogens, which comprises contacting the Streptomyces oryzae described in the first aspect or the bacterial agent described in the second aspect with the plant pathogens.

[0058] Preferably, the plant pathogen is selected from at least one of tomato wilt pathogen, corn leaf blight pathogen, tobacco anthracnose pathogen, tsaoko leaf spot pathogen, tobacco black shank pathogen and banana wilt pathogen.

[0059] The sixth aspect of the present invention provides a method for preventing and controlling soil-borne plant diseases and / or promoting plant growth, the method comprising applying the blastomyces oryzae and / or its metabolites described in the first aspect, or the bacterial agent described in the second aspect, to the rhizosphere soil of the plant.

[0060] According to a preferred embodiment of the present invention, the application amount of Streptomyces oryzae is not less than 1×10 8 CFU / strain / time, preferably 1×10 9 -1×10 12 CFU / strain / time.

[0061] According to a preferred embodiment of the present invention, the amount of the bacterial agent is such that the amount of Streptomyces oryzae applied is not less than 1×10 8 CFU / strain / time, preferably 1×10 9 -1×10 12 CFU / plant / time. Preferably, the application frequency of the Streptomyces oryzae or the bacterial agent is 1-3 times per crop.

[0062] According to a preferred embodiment of the present invention, the dosage of the metabolite is not less than 100 mL / plant / time, preferably 100-200 mL / plant / time.

[0063] Preferably, the frequency of application of the metabolite is 1 to 3 times per crop.

[0064] More preferably, the metabolite comprises auxin.

[0065] According to a preferred embodiment of the present invention, the metabolites are provided by the fermentation broth of the Streptomyces oryzae. The fermentation broth can be obtained by the fermentation culture method as described above, and the specific method and conditions are not repeated here.

[0066] Preferably, the content of auxin in the metabolites may be 20-40% (w / v), preferably 30-37% (w / v).

[0067] More preferably, the content of auxin (indoleacetic acid) in the metabolites may be 10-30 μg / mL. Preferably, it may be 15-25 μg / mL. For example, it may be 15 μg / mL, 16 μg / mL, 17 μg / mL, 18 μg / mL, 19 μg / mL, 20 μg / mL, 21 μg / mL, 22 μg / mL, 23 μg / mL, 24 μg / mL, 25 μg / mL, or it may be a range consisting of any two of the above values, or any intermediate value in the range.

[0068] In the present invention, the fermentation broth can be directly applied (after dilution / concentration to make the auxin content reach the above level), or the auxin in the fermentation broth can be purified and then prepared into a separate preparation for application. The purification method can be any method in the art that can be used to separate and purify auxin.

[0069] Preferably, the seeds are selected from the Solanaceae family, preferably Solanum spp., most preferably Tomato; and / or, selected from the Solanaceae family, preferably Capsicum spp., most preferably Capsicum spp.; and / or, selected from the Cucurbitaceae family, preferably Cucumis spp., most preferably Cucumber.

[0070] According to some preferred embodiments of the present invention, the method further comprises applying halotolerant Bacillus CCTCC NO: M20232276 in the rhizosphere soil of the plant.

[0071] Preferably, the application amount of the salt-tolerant Bacillus CCTCC NO: M20232276 is not less than 1×10 8 CFU / strain / time, preferably 1×10 9 -1×10 12 CFU / strain / time.

[0072] More preferably, the application frequency of the halodurable Bacillus CCTCC NO: M20232276 is 1-3 times per crop.

[0073] In the method provided by the present invention, the Streptomyces oryzae and the halotolerant Bacillus CCTCC NO: M20232276 provided by the present invention can be applied to the rhizosphere soil of the plant together, or can be applied in batches and sequentially.

[0074] Furthermore, the present invention also provides a composite bacterial agent comprising the aforementioned Streptomyces oryzae and Bacillus halodurans CCTCC NO: M20232276.

[0075] Furthermore, the present invention also provides the use of the above-mentioned bacterial agent in promoting plant growth, improving soil (improving soil quality), enhancing plant disease resistance, preventing and controlling plant diseases (especially soil-borne diseases), and promoting plant growth.

[0076] The present invention will be described in detail below by way of examples. It should be understood that the following examples are only used to further explain and illustrate the content of the present invention by way of example, and are not intended to limit the present invention.

[0077] In the following examples, unless otherwise specified, the reagents and materials used were all commercial products purchased from regular chemical / biological reagent or material suppliers, and the reagents were all analytical grade.

[0078] In the following examples, unless otherwise specified, the operating temperature is room temperature (25±5° C.).

[0079] Example 1

[0080] This example is used to illustrate the acquisition, identification and preservation of Streptomyces oryzae CCTCC NO: M 20231643.

[0081] (I) Strain isolation and purification

[0082] Gao's medium No. 1 was used in the strain isolation and purification process. The preparation method was as follows: weigh soluble starch (20.00 g), KNO3 (1.00 g), K2HPO4 (1.00 g), MgSO4·7H2O (0.50 g), NaCl (0.50 g), and FeSO4·7H2O (0.50 g), add to 1000 mL of water to dissolve, adjust the pH to 7.3±0.1, add 20.00 g of agar, sterilize with high-pressure steam at 121°C for 20 min, and set aside.

[0083] An actinomycete was isolated and purified from the rhizosphere soil samples of Pinus armandii collected from Wuliangshan National Nature Reserve by using the dilution spread plate method and the plate streak method, and was named YNK-FS0018.

[0084] (II) Strain identification

[0085] 1. Identification of bacterial morphological, physiological and biochemical characteristics

[0086] Physiological and biochemical tests were performed on strain YNK-FS0018 according to the Bergey's Manual of Bacterial Identification and the Manual of Identification of Common Bacterial Systems, and the colony morphology characteristics were described.

[0087] Colony & Cell Morphology: Figure 1 The colony morphology of strain YNK-FS0018 on Gao's medium No. 1 is shown. It can be seen from the figure that the colony of this strain is nearly circular, with irregular edges, light yellow, and a bulge in the middle of the colony.

[0088] Physiological and biochemical characteristics: The strain YNK-FS0018 is Gram-positive, with a salt tolerance range of 0-5% (w / v) and a pH tolerance range of 4-8, indicating that the strain has a certain salt and acid resistance. The colony of YNK-FS0018 is light yellow-white with slight protrusions. It is a Gram-positive bacterium that can hydrolyze starch and weakly use citrate.

[0089] 2. Molecular identification

[0090] The total DNA of strain YNK-FS0018 was extracted by Chelex extraction method as a template, 27F (5'-AGAGTTTGATCCTGGCTCAG-3') was used as the upstream primer, 1492R (5'-TAC GGCTACCTTGTTACGACTT-3') was used as the downstream primer, and 16S rRNA was amplified using the reaction system and conditions in Table 1.

[0091] Table 1 PCR system and conditions

[0092]

[0093] The amplified product was purified and recovered by 1% agarose gel electrophoresis using a gel recovery and purification kit produced by Guangzhou Meiji Biotechnology Co., Ltd., and then sent to Beijing Qingke Biotechnology Co., Ltd. for sequencing. The sequencing results were compared and analyzed in the NCBI database (https: / / www.ncbi.nlm.nih.gov / ) and the EZBiocloud database (https: / / www.ezbiocloud.net / ). The phylogenetic analysis method was used, and the 16S rRNA sequence of the model strain with high homology was selected as the reference object. The Clustal X 1.8 software was used for multiple sequence alignment to calculate the similarity between the test strain and the reference strain sequence. The base deletion sites were excluded during the phylogenetic analysis, and the neighbor-joining analysis was used to construct the phylogenetic tree between the test strain and the reference strain using MEGA 7.0. Among them, the Bootstrap value was set to 1000, and the rest were the default values.

[0094] Figure 2 The phylogenetic tree of strain YNK-FS0018 is shown, from which it can be seen that YNK-FS0018 has the highest homology with Streptomyces blastmyceticus NRRLB-5480.

[0095] 3. Identification results

[0096] Combining the molecular detection results of strain YNK-FS0018 with the bacterial morphological characteristics and physiological and biochemical characteristics, the strain was identified as Streptomyces blastmyceticus.

[0097] 3. Strain preservation

[0098] The Streptomyces blastmyceticus YNK-FS0018 obtained above was deposited in the China Center for Type Culture Collection on September 7, 2023, at 299 Bayi Road, Wuchang District, Wuhan City, Hubei Province, Wuhan University, with the deposit number of CCTCC NO: M 20231643.

[0099] Example 2

[0100] This example is used to illustrate the effects of Streptomyces oryzae CCTCC NO: M 20231643 in degrading organic phosphorus and antagonizing pathogens.

[0101] (I) Solution of organic phosphorus

[0102] Preparation method of organophosphorus solid culture medium: weigh 10g glucose, 0.5g ammonium sulfate, 0.5g yeast extract powder, 0.3g sodium chloride, 0.3g potassium chloride, 0.3g magnesium sulfate, 0.03g ferrous sulfate, 0.03g manganese sulfate, 0.2g lecithin, 1g calcium carbonate, add to 1000mL water to dissolve, adjust pH to 7.3±0.2, add 18±2g agar, and sterilize at 121℃ for 20min.

[0103] The strain YNK-FS0018 obtained in Example 1 was inoculated on an organophosphate culture plate using the four-point plate inoculation method, and the inoculation was repeated for 3 plates. After the inoculation was completed, the plate was placed in a 30°C constant temperature incubator for 5 days, and the bacterial growth and the formation of transparent circles around the colonies were observed every day during the incubation period.

[0104] Figure 3 The figure shows the effect of strain YNK-FS0018 on degrading organic phosphorus. It can be seen from the figure that strain YNK-FS0018 can produce transparent circles when cultured on organic phosphorus culture plates. The size of the transparent circle was measured by the cross method, and the ratio of the transparent circle diameter (D) to the colony diameter (d) was calculated to be D / d = 2.925 ± 0.87. This shows that the strain has a good ability to degrade organic phosphorus.

[0105] (II) Broad-spectrum antibacterial activity of YNK-FS0018

[0106] Use an inoculation needle to pick up the mycelium block of the pathogen, place it in a PDA culture dish and culture it for 5 days, use a puncher to punch a 0.50 cm pathogen cake on the edge of the pathogen, place it in the center of a new PDA culture dish, use an inoculation needle to pick up the activated YNK-FS0018 from the culture dish, cross-inoculate the strain 2.50 cm away from the pathogen, use the culture dish inoculated with only the pathogen as a control, and culture it in a 28°C incubator for 3-5 days (the specific culture time is determined according to the growth of the pathogen and YNK-FS0018, and the culture can be stopped when the plate inoculated with only the pathogen is full of mycelium). The inhibitory effect on pathogens is expressed by inhibition rate, and the calculation method is as follows. Table 2 and Figure 4 The inhibitory effect of strain YNK-FS0018 on various pathogens is shown in FIG.

[0107] Inhibition rate = [(control colony diameter - treated colony diameter) / control colony diameter] × 100%

[0108] Table 2 Inhibition rate of YNK-FS0018 against different pathogens

[0109] Pathogens YNK-FS0018 antibacterial rate (%) Tomato wilt pathogen Fusarium oxysporum 79.52 Exserohilum turcicum 82.75 Tobacco Anthracnose Pathogen Colletotrichum micotianae 75.34 Phoma matteuciicola 86.48 Phytophthora parasitica 80.45 Banana wilt pathogen Fusarium oxysporum fsp. Cubense race4 (Foc4) 70.47

[0110] From the data in the table, it can be seen that the inhibition rate of YNK-FS0018 against the tested pathogens is as high as over 70%, among which the inhibition rate against the leaf spot pathogen of the genus Amomi is as high as 86.48%, indicating that the rice blast fungus Streptomyces has a good application prospect in biological control.

[0111] Example 3

[0112] This example is used to illustrate the effect of secretion of auxin by Streptomyces oryzae CCTCC NO: M 20231643.

[0113] The activated Streptomyces oryzae YNK-FS0018 was inoculated into KB medium and cultured at 30°C and 180 rpm for 24 h. 1 mL of the fermentation liquid was aseptically pipetted into a centrifuge tube and quickly mixed with 4 mL of Sackowcki's color developer. The tube was incubated at room temperature in the dark for 40 min to develop color. The color change was observed and recorded. If pink appeared, it was positive, indicating that the strain could secrete IAA.

[0114] After the strain was cultured in Gao's medium No. 1 for 1 day, the seed solution was prepared and inoculated into KB liquid medium containing L-tryptophan at a 1% inoculum (the initial content of YNK-FS0018 in the culture system after inoculation was about 1.8×10 6CFU / mL), placed in a 30°C constant temperature shaker with 180r / min shaking culture, 4mL of supernatant was taken every day and mixed with 4mL of Sackowcki's colorimetric reagent, and after standing for 40min in a dark environment, the OD value was measured at a wavelength of 535nm. The obtained absorbance value was substituted into the standard curve for calculation to obtain the indoleacetic acid content of the strain. It was determined that the indoleacetic acid content of strain YNK-FS0018 was the highest at 20.57±0.21μg / mL on the third day.

[0115] Example 4

[0116] This example is used to illustrate the effect of Streptomyces oryzae CCTCC NO: M 20231643 in degrading benzoic acid.

[0117] Benzoic acid inorganic salt culture medium: MgSO4·7H2O 0.20g; (NH4)2SO4 1g; KH2PO4 0.50g; NaCl0.50g; K2HPO4 1.50g, benzoic acid 0.1g, distilled water 1000mL, natural pH; sterilize at 121℃ for 20min.

[0118] The YNK-FS0018 screened in Example 1 was activated and inoculated into 20 mL of Gao's No. 1 liquid culture medium, and cultured in a shaker at 30°C and 180 r / min for 24 h as a seed solution. 1 mL of the seed solution was inoculated into 50 mL of an inorganic salt liquid culture medium with benzoic acid as a substrate, and the substrate concentration was 0.10 g / L. The zero-time sample and the end-time sample of 4 days of shaking culture at 37°C and 180 r / min were taken respectively, and the residual amount of the substrate (benzoic acid) was detected by HPLC after filtration, so as to calculate the substrate degradation efficiency.

[0119] The conditions of HPLC were as follows: the fermentation broth to be tested was added into a 50 mL centrifuge tube, centrifuged at 4°C and 8000 rpm for 10 min, 1.00 mL of the supernatant was filtered through a 0.22 μm microporous filter membrane as the input sample, and the chromatographic column used was an Agillent C18 column (250 mm × 4.0 mm × 5 μm); the column temperature was 35°C; the UV detection wavelength was 230 nm; the mobile phase was methanol: 0.02 mol / L, ammonium acetate = 5:95; the flow rate was 1.00 mL / min; the injection volume was 10.00 μL, and the elution was isocratic.

[0120] Degradation rate = [(substrate amount at zero time - substrate amount at the end of time) / substrate amount at zero time] × 100%

[0121] The results showed that after YNK-FS0018 was cultured in benzoic acid inorganic salt medium for four days, no benzoic acid was detected in the culture medium, indicating that the strain completely degraded and utilized benzoic acid with a degradation rate of 100%.

[0122] Example 5

[0123] This example is used to illustrate the effect of Streptomyces oryzae CCTCC NO: M 20231643 on alleviating the inhibition of seed germination by benzoic acid.

[0124] The experiment set up three treatments: 1) clean water control (CK1); 2) 1.00 g / L benzoic acid treatment (CK2); 3) YNK-FS0018 bacterial suspension (experimental group).

[0125] Preparation method of bacterial suspension in experimental group: YNK-FS0018 strain was inoculated into Gao's liquid medium No. 1 at a 1% inoculation rate, and cultured in a constant temperature shaker at 30°C and 180 rpm for 48 h until the concentration of bacterial suspension reached 1.8×10 8 CFU / mL, centrifuge at 8000 rpm for 10 min at 4°C, discard the supernatant, resuspend with sterile water and dilute to the above concentration for use.

[0126] Tomato, pepper and cucumber seeds were selected as experimental objects. The seeds were soaked in 70% alcohol for 10 minutes and then washed with sterile water for 3 times to complete disinfection. Take the seeds that have settled under the water, soak them in water at room temperature for 12 hours, then take each group of seeds and place them in a 9.00cm transparent culture dish with 2-3 layers of sterilized filter paper. Each dish has 10 seeds for each treatment, and repeat 3 times. Treatment 3) First, use 2.00mL of bacterial suspension to inject into the culture dish, soak the sterilized paper and culture the seeds on the moist sterilized paper for 24 hours, then continue to inject 2.00mL of benzoic acid into the culture dish to culture the seeds on the sterilized paper containing benzoic acid solution for 24 hours, and then inject 2.00mL of sterile water into the culture dish every 24 hours to keep the sterilized paper moist. For other treatments, inject 2.00mL of the required liquid into the culture dish and add 2.00mL of sterile water every 24 hours after treatment. The seeds were germinated in an artificial climate box at 26°C, with alternating light and dark periods of 16 h and 8 h, and the germination rate and plant length were measured 7 days after the bacterial suspension treatment. Figure 5 The figure shows the alleviating effect of strain YNK-FS0018 on the inhibition of seed germination by benzoic acid.

[0127] Germination index determination: whether the seeds have germinated after treatment is determined by the standard of whitening>1 / 2 seed length, seed germination rate (%) = (number of germinated seeds / number of test seeds) × 100%.

[0128] Table 3 Results of YNK-FS0018 alleviating benzoic acid inhibition of seed germination

[0129]

[0130] From the data, we can see that benzoic acid inhibits the germination of tomato, pepper and cucumber seeds, but after adding strain YNK-FS0018, the seed germination rate is improved, and even the germination rate of cucumber and tomato seeds is improved compared with the water control; in addition, the full length of tomato, cucumber and pepper is improved compared with the control. This shows that YNK-FS0018 can degrade benzoic acid and promote seed germination.

[0131] Example 6

[0132] This example is used to illustrate the control effect of Streptomyces oryzae CCTCC NO: M 20231643 on tomato wilt.

[0133] Preparation of bacterial agent: The strain YNK-FS0018 obtained in Example 1 was inoculated into Gao's liquid medium No. 1 and cultured at 30°C and 180 rpm for 72 h. The resulting fermentation liquid was the bacterial agent of strain YNK-FS0018 (the viable count was about 6×10 8 CFU / mL).

[0134] Plant planting: Add the same weight of soil to each pot, randomly group 10 pots per treatment, and plant one tomato seedling of similar growth in each pot.

[0135] Verification of the effect of preventing and controlling wilt disease: On the third day after the tomato seedlings were transplanted into the pots, the tomato seedlings were irrigated with tomato wilt bacteria (Fusarium oxysporum), and a small hole was pierced at the root of the seedlings during the root irrigation. After three days of root irrigation with tomato wilt bacteria to allow the pathogen to colonize, the tomato seedlings were irrigated with the above-mentioned bacterial agent, and the same amount of sterile water was used as the control group (CK).

[0136] After the root irrigation treatment, the tomato seedlings were placed in a greenhouse to grow naturally. After 45 days of root irrigation treatment, the incidence rate and disease index of the tomato plants were measured. The results are shown in Table 4.

[0137] The disease conditions of each treatment were graded according to the tomato wilt disease classification standard: 0: no symptoms; 1: one or two leaves turn yellow; 2: three or four true leaves turn yellow and wilt and droop; 3: five or six true leaves turn yellow or wilt and droop; 4: the whole plant wilts severely and dies.

[0138] Disease index = (number of diseased plants at each level × value of the disease level) / (total number of plants × highest level value) × 100.

[0139] Preventive effect = (disease index of control group - disease index of treatment group) / disease index of control group × 100.

[0140] Table 4 The protective effect of YNK-FS0018 on tomato wilt

[0141] Measurement indicators CK Experimental Group Disease index 25.83±0.21a 3.33±0.08b Prevention effect (%) - 87.10±0.18a

[0142] In Table 4, "-" indicates no protective effect, and different letters after the data indicate significant differences. From the above data, it can be seen that after adding the YNK-FS0018 bacterial agent, tomato wilt disease was well controlled, the disease index decreased significantly, and the protective effect reached more than 87%, indicating that the strain has great application potential in the prevention and control of tomato wilt disease.

[0143] Example 7

[0144] This example is used to illustrate the growth-promoting effect and soil-improving effect of Streptomyces oryzae CCTCC NO: M 20231643.

[0145] (I) Verification of growth-promoting effect

[0146] The same weight of soil was added to each flower pot, and 10 pots were randomly divided into groups for each treatment, and one tomato seedling with similar growth was planted in each pot. On the third day after the tomato seedlings were transplanted into the pots, the tomato seedlings were irrigated with 100 mL / plant of the above-mentioned bacterial agent, and the same amount of sterile water was used for the same treatment as the control group 1 (CK1), and the same amount of Gao's No. 1 medium was used for the same treatment as the control group 2 (CK2).

[0147] After the root irrigation treatment, the tomato seedlings were placed in a greenhouse to grow naturally. After 45 days of root irrigation treatment, the aboveground fresh weight and dry weight, underground (root) fresh weight and dry weight, stem diameter, root length and plant height of the tomato plants were measured.

[0148] The specific measurement method is as follows:

[0149] Aboveground fresh weight & dry weight: Cut the part above the root base of the tomato plant and weigh the aboveground fresh weight on an analytical balance, retaining one decimal place. Put the aboveground part of the plant weighed fresh weight into a paper bag and put it into an oven at 100±5℃ for 10 minutes, then lower the temperature of the oven to 75±5℃, dry to constant weight, and weigh the aboveground dry weight on an analytical balance, retaining one decimal place.

[0150] Underground fresh weight & dry weight: Cut the part below the root base of the tomato plant and weigh the fresh weight of the underground part on an analytical balance, retaining one decimal place. Put the underground part of the plant weighed fresh weight into a paper bag and put it into an oven at 100±5℃ for 10 minutes, then lower the temperature of the oven to 75±5℃, dry it to constant weight, and weigh it on an analytical balance to obtain the dry weight of the underground part, retaining one decimal place.

[0151] Stem Diameter: Use a caliper to measure the diameter of the thickest stem part of the plant.

[0152] Root length: Straighten the roots and measure the root length using a ruler.

[0153] Plant height: Straighten the plant and use a ruler to measure the length of the above-ground part from the highest point of the leaves.

[0154] Table 5 shows the growth index measurement results of tomato seedlings in the control group and the experimental group.

[0155] Table 5 Growth status of tomato seedlings

[0156] Growth indicators CK1 CK2 Experimental Group Fresh weight above ground (g) 31.93±1.78c 39.45±1.32b 53.50±2.64a Above ground dry weight (g) 5.71±0.33c 6.15±0.21a 9.00±0.14a Root weight (g) 7.07±0.12c 9.20±0.07b 12.29±0.52a Stem diameter (mm) 5.24±0.07b 5.31±0.04b 5.74±0.08a Root length (cm) 12.03±0.60c 13.56±0.46b 21.33±0.67a Plant height (cm) 84.23±3.43c 99.17±4.23b 129.33±8.66a

[0157] *The data in the table with different letters indicate significant differences

[0158] From the data in the table above, it can be seen that after the root irrigation treatment with YNK-FS0018 bacterial agent, the plant height, stem diameter, aboveground fresh weight, root length, and root fresh weight of tomato plants were significantly improved compared with the control group (CK1) with water and the control group (CK2) with Gao's medium No. 1. According to calculations, the net increase in plant height of tomatoes in the experimental group reached 53.40% compared with CK1, the stem diameter increased by 9.40%, the aboveground fresh weight increased by 67.50%, the aboveground dry weight increased by 57.50%, the root length increased by 77.28%, and the root weight increased by 73.50%, indicating that the strain YNK-FS0018 can effectively promote plant growth. There was a significant difference between the control group and the control group except for the stem diameter (P<0.05). It shows that the inoculation of rhizosphere strain YNK-FS0018 has a significant promoting effect on the growth of tomatoes.

[0159] 2. Verification of soil improvement effect

[0160] After the tomato (45 days) cultivation was completed, the rhizosphere soil of each group of tomatoes was collected, and the soil samples were tested for soil physical and chemical properties such as pH, organic matter, total nitrogen, total phosphorus, total potassium, alkaline nitrogen, available phosphorus, and effective potassium to verify the soil improvement effect of strain YNK-FS0018. The test results are detailed in Table 6.

[0161] The specific detection methods are as follows:

[0162] The organic matter was determined by chromic acid redox titration, the pH value was determined by potentiometric method, the total nitrogen was determined by Kjeldahl method, the total phosphorus was determined by sodium hydroxide alkali fusion-molybdenum antimony colorimetry, the total potassium and available potassium were determined by flame photometry, the alkaline nitrogen was determined by diffusion absorption method, and the available phosphorus was determined by 0.5 mol / L NaHCO3-molybdenum antimony colorimetry.

[0163] Table 6 Test results of soil sample physical and chemical properties

[0164] Detection indicators CK1 CK2 Experimental Group pH 7.1 7.4 7.0 Organic matter (g / kg) 163.8 179.6 88 Total nitrogen (g / kg) 3.75 3.78 3.06 Total phosphorus (g / kg) 1.09 1.12 1.20 Total potassium (g / kg) 6.35 6.78 7.36 Hydrolyzable nitrogen (mg / kg) 289 302 256 Available phosphorus (mg / kg) 115.6 124.7 76.5 Available potassium (mg / kg) 216 289 354

[0165] From the data in the table, it can be seen that there is no significant difference in pH value, total phosphorus and total nitrogen among the three treatments, but the total potassium and available potassium contents of the experimental group are higher than those of the two control groups, and the contents of organic matter, total nitrogen, available phosphorus and hydrolyzable nitrogen are lower than those of the control group. When analyzed together with the tomato plant growth data in Table 5, it can be inferred that the strain YNK-FS0018 has the function of decomposing organic phosphorus, converting the nutrients in the soil into available phosphorus that can be absorbed by plants, and fully absorbed by the tomato root system, so that the organic matter content of tomato plants increases and nutrients accumulate, thereby reducing the phosphorus content in the soil environment after planting. At the same time, it is speculated that under the influence of the growth-promoting effect of the strain YNK-FS0018, the total potassium and available potassium contents of the soil have increased, and the contents of hydrolyzable nitrogen and total nitrogen have decreased, indicating that the presence of the strain may promote the transformation and utilization of nitrogen elements by other microorganisms, proving that the strain YNK-FS0018 has a good improvement effect on the soil, and can have a significant growth-promoting effect on tomato growth.

[0166] (III) Verification of soil enzyme activity improvement effect

[0167] After the tomato (45 days) cultivation was completed, the rhizosphere soil of each group of tomatoes was collected, and the soil samples were tested for soil physical and chemical properties such as urease, sucrase, acid phosphatase, and catalase to verify the soil improvement effect of strain YNK-FS0018. The test results are detailed in Table 7.

[0168] The specific detection methods are as follows:

[0169] The urease activity was determined by indophenol colorimetry; the sucrose invertase activity was determined by 3,5-dinitrosalicylic acid colorimetry; the acid phosphatase activity was determined by disodium phenyl phosphate colorimetry; and the catalase activity was determined by potassium permanganate titration.

[0170] Table 7 Soil enzyme activity test results

[0171] Detection indicators CK1 CK2 Experimental Group <![CDATA[Invertase (mg·d -1 ·g -1 )]]> 4.39 5.21 7.18 <![CDATA[Urease (μg·d -1 ·g -1 )]]> 286.31 305.44 323.45 <![CDATA[Acid phosphatase (μmol·d -1 ·g -1 )]]> 8.56 9.85 14.25 Catalase (mg / g·d) 2.13 3.08 4.26

[0172] From the data in the table, it can be seen that the activities of soil sucrose invertase, urease, acid phosphatase and catalase are all improved compared with the two controls. Combined with the changes in soil physical and chemical indicators in Table 6, it shows that strain YNK-FS0018 increases the content of these enzymes in the soil, thereby promoting the conversion of available phosphorus, available nitrogen and available potassium in the soil, providing plants with more nutrients, thereby promoting the healthy growth of plants.

[0173] Example 8

[0174] This example is used to illustrate the growth-promoting effect of the composite bacterial agent of Streptomyces oryzae CCTCC NO: M 20231643 and Bacillus halodurans CCTCC NO: M20232276.

[0175] (I) Verification of growth-promoting effect

[0176] Add the same weight of soil to each pot, randomly group 10 pots per treatment, and plant a tomato seedling of similar growth in each pot. Set up the treatment groups as follows:

[0177] 1) T1: On the third day after the tomato seedlings were transplanted into the pots, 100 mL / plant of a solution containing 6×10 8 CFU / mL of Streptomyces oryzae was used to irrigate the roots of tomato seedlings. 8 CFU / mL of salt-tolerant Bacillus CCTCC NO: M20232276 was used for root irrigation; 2) T2: On the third day after the tomato seedlings were transplanted into the pots, 100 mL / plant of the bacterial agent with a bacterial content of 6×10 8 CFU / mL of Streptomyces oryzae was used to irrigate the roots of tomato seedlings; 3) T3: On the third day after the tomato seedlings were transplanted into the pots, 100 mL / plant of Streptomyces oryzae containing 7×10 8 CFU / mL of the bacillus halodurans CCTCC NO: M20232276 was used to irrigate the tomato seedlings; 4) CK: the same amount of sterile water was used as the control group. The tomato seedlings after the root irrigation treatment were placed in a greenhouse to grow naturally.

[0178] After 45 days of root irrigation treatment (for root irrigation with two kinds of bacterial agents, the time of the first root irrigation treatment was used for calculation), the aboveground fresh weight and dry weight, underground (root) fresh weight and dry weight, stem diameter, root length and plant height of tomato plants were measured. The results are shown in Table 8. The specific measurement method is as follows:

[0179] Aboveground fresh weight & dry weight: Cut the part above the root base of the tomato plant and weigh the aboveground fresh weight on an analytical balance, retaining one decimal place. Put the aboveground part of the plant weighed fresh weight into a paper bag and put it into an oven at 100±5℃ for 10 minutes, then lower the temperature of the oven to 75±5℃, dry to constant weight, and weigh the aboveground dry weight on an analytical balance, retaining one decimal place.

[0180] Underground fresh weight & dry weight: Cut the part below the root base of the tomato plant and weigh the fresh weight of the underground part on an analytical balance, retaining one decimal place. Put the underground part of the plant weighed fresh weight into a paper bag and put it into an oven at 100±5℃ for 10 minutes, then lower the temperature of the oven to 75±5℃, dry it to constant weight, and weigh it on an analytical balance to obtain the dry weight of the underground part, retaining one decimal place.

[0181] Stem Diameter: Use a caliper to measure the diameter of the thickest stem part of the plant.

[0182] Root length: Straighten the roots and measure the root length using a ruler.

[0183] Plant height: Straighten the plant and use a ruler to measure the length of the above-ground part from the highest point of the leaves.

[0184] Table 8 Growth status of tomato seedlings

[0185] Growth indicators CK T1 T2 T3 Fresh weight above ground (g) 31.93±1.78c 56.48±1.58a 53.50±2.64a 46.21±0.60b Above ground dry weight (g) 5.71±0.33c 9.57±0.24a 9.00±0.14a 7.22±0.15b Root weight (g) 7.07±0.12c 13.47±0.11a 12.29±0.52a 12.39±0.41a Stem diameter (mm) 5.24±0.07b 6.13±0.09a 5.74±0.08a 5.71±0.03a Root length (cm) 12.03±0.60c 23.26±0.37a 21.33±0.67a 22.83±1.46a Plant height (cm) 84.23±3.43c 116.89±0.59b 129.33±8.66a 104.90±1.61b

[0186] *The data in the table with different letters indicate significant differences

[0187] From the data in the table above, it can be seen that after the root irrigation treatment with the combined application of Streptomyces oryzae CCTCC NO: M20231643 and Bacillus halodurans CCTCC NO: M20232276, the stem diameter, fresh and dry weight of the aboveground part, and root length of the tomato plants were all improved compared with the treatment of adding any of the aboveground agents alone and the control group (CK) with water, indicating that the composite agent has a better growth-promoting effect. According to calculations, the stem diameter of tomatoes in T1 increased by 6.79% and 7.35% compared with T2 and T3, respectively; the fresh weight of the aboveground part increased by 5.57% and 22.22%, respectively; the dry weight of the aboveground part increased by 5.96% and 32.55%, respectively; the root length increased by 9.05% and 1.88%, respectively; and the root weight increased by 9.6% and 9.49%, respectively.

[0188] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A strain of Streptomyces blastmyceticus, characterized in that: The deposit number of this strain is CCTCC NO:M 20231643.

2. A bacterial agent, characterized in that The bacterial agent comprises the Streptomyces oryzae described in claim 1.

3. The bacterial agent according to claim 2, wherein The bacterial agent is a liquid bacterial agent.

4. The bacterial agent according to claim 3, wherein The content of Streptomyces oryzae in the bacterial agent is not less than 1×10 6 CFU / mL.

5. The bacterial agent according to claim 4, wherein The content of Streptomyces oryzae in the bacterial agent is 1×10 7 -1×10 10 CFU / mL.

6. The Streptomyces oryzae of claim 1, or the bacterial agent of any one of claims 2 to 5 for use in degrading benzoic acid, degrading organic phosphorus, secreting auxin, antagonizing pathogens or alleviating the inhibitory effect of benzoic acid on seed germination; The pathogen is at least one of tomato wilt pathogen (Fusarium oxysporum), corn leaf spot pathogen (Exserohilum turcicum), tobacco anthracnose pathogen (Colletotrichum micotianae), grass fruit stem spot pathogen (Phomamatteuciicola), tobacco black shank pathogen (Phytophthora parasitica) and banana wilt pathogen (Fusarium oxysporum fsp. Cubenserace4 (Foc4)).

7. A method for preparing auxin, characterized in that: The method comprises culturing the Streptomyces oryzae according to claim 1 and collecting the culture product.

8. The method according to claim 7, wherein: The culture conditions include: culture temperature 28-32° C., and culture time 72-96 h.

9. Use of the Streptomyces oryzae according to claim 1, or the bacterial agent according to any one of claims 2 to 5, in improving soil, and / or promoting plant growth, and / or promoting plant seed germination, and / or preventing and controlling the occurrence of soil-borne diseases, and / or preventing and controlling the spread of soil-borne diseases; in, The plant is selected from the Solanaceae and / or Cucurbitaceae plants; Soil-borne diseases are diseases caused by at least one of tomato wilt pathogen (Fusarium oxysporum), corn leaf spot pathogen (Exserohilum turcicum), tobacco anthracnose pathogen (Colletotrichum micotianae), grass fruit stem spot pathogen (Phomamatteuciicola), tobacco black shank pathogen (Phytophthora parasitica) and banana wilt pathogen (Fusarium oxysporum fsp. Cubenserace4 (Foc4)).

10. A method for preventing and controlling soil-borne plant diseases and / or promoting plant growth, characterized in that: The method comprises applying the Streptomyces oryzae described in claim 1 or the bacterial agent described in any one of claims 2 to 5 to the rhizosphere soil of the plant; Wherein, the plant is selected from Solanaceae and / or Cucurbitaceae plants; The soil-borne disease is a disease caused by at least one of tomato wilt pathogen (Fusarium oxysporum), corn leaf spot pathogen (Exserohilum turcicum), tobacco anthracnose pathogen (Colletotrichum micotianae), grass fruit stem spot pathogen (Phomamatteuciicola), tobacco black shank pathogen (Phytophthora parasitica) and banana wilt pathogen (Fusarium oxysporum fsp. Cubenserace4 (Foc4)).

11. The method according to claim 10, wherein: The application amount of Streptomyces oryzae is not less than 1×10 8 CFU / strain / time; or The dosage of the bacterial agent is such that the dosage of Streptomyces oryzae is not less than 1×10 8 CFU / strain / time.

12. The method according to claim 11, wherein: The application amount of Streptomyces oryzae is 1×10 9 -1×10 12 CFU / strain / time; or The dosage of the bacterial agent is such that the dosage of Streptomyces oryzae is 1×10 9 -1×10 12 CFU / strain / time.

13. The method according to claim 10, wherein: The application frequency of the rice blast fungus or the bacterial agent is 1 to 3 times per crop.

14. The method according to claim 10, wherein: The plant is at least one of tomato, pepper and cucumber.

15. The method according to any one of claims 10 to 14, wherein: The method further comprises applying halotolerant Bacillus CCTCC NO: M20232276 in the rhizosphere soil of the plant.

16. The method according to claim 15, wherein: The application amount of the salt-tolerant Bacillus CCTCC NO: M20232276 is not less than 1×10 8 CFU / strain / time.

17. The method according to claim 16, wherein: The application amount of the salt-tolerant Bacillus CCTCC NO: M20232276 is 1×10 9 -1×10 12 CFU / strain / time.

18. The method according to claim 15, wherein: The application frequency of the halotolerant Bacillus CCTCC NO: M20232276 is 1 to 3 times per crop.

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