Pseudomonas aeruginosa, fungicide and application of pseudomonas aeruginosa in biological control of diseases and plant growth promotion

Abstract

The invention discloses broad bean pseudomonas, a fungicide and application of the broad bean pseudomonas in biological control of diseases and plant growth promotion, and relates to the technical field of biocontrol bacteria. The preservation number of the broad bean pseudomonas is CGMCC (China General Microbiological Culture Collection Center) No.32657. The strain has growth promoting and biocontrol functions, can effectively prevent and treat various Chinese herbal medicine and crop diseases and promote plant growth, and has a good application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of biocontrol bacteria, and in particular, to a Pseudomonas viciae, a bacterial agent and their applications in biological control of diseases and plant growth promotion. Background Art

[0002] Eucommia ulmoides is a traditional Chinese medicinal material in China and also a forest-source medicinal tree species and forage tree species in the field of traditional Chinese medicine. The whole body of Eucommia ulmoides has extremely high utilization value, and its dried bark and leaves are both used as raw materials for medicinal components. Eucommia ulmoides leaves are the dried leaves of the medicinal plant Eucommia ulmoides Oliv. of the Eucommiaceae family. They have been included in the Chinese Pharmacopoeia in 2005, 2015, and 2020 editions, and have the effects of lowering blood pressure, strengthening bones and muscles, treating liver and kidney deficiency, dizziness and vertigo, and lumbar pain. The medicinal history of Eucommia ulmoides leaves can be traced back to ancient times. There is a record in the Illustrated Classic of Materia Medica in the Song Dynasty that "the newly grown tender leaves of Eucommia ulmoides can be eaten." In 2023, Eucommia ulmoides leaves were officially included in the list of homologous medicines and foods, and their raw materials are widely used in the development of health products such as Eucommia ulmoides tea, Eucommia ulmoides wine, Eucommia ulmoides vinegar, and Eucommia ulmoides fine powder, and are also used in green breeding. Therefore, Eucommia ulmoides leaves have broad application prospects in the fields of medicine, food, health products, and feed.

[0003] With the continuous increase in the market demand for Eucommia ulmoides raw materials, the area of its artificial cultivation has also expanded rapidly. However, due to the over-concentration of planting plots, the fungal diseases of Eucommia ulmoides leaves (such as leaf spot disease, leaf blight disease, gray mold disease, etc.) are becoming increasingly serious, restricting the sustainable development of the Eucommia ulmoides industry. Among them, Eucommia ulmoides leaf blight is particularly prominent. At the initial stage of the disease, sporadic lesions appear on the leaves, and then the lesion area rapidly expands and spreads, eventually causing the whole plant leaves to wither. Especially for 1-2-year-old Eucommia ulmoides seedlings, the disease is severe, resulting in a significant decline in their yield and quality, bringing huge economic losses to growers and planting parks.

[0004] The gray mold pathogen has characteristics such as high host diversity, strong genetic variability, and easy resistance to a variety of chemical agents, resulting in the problem of Chinese medicinal material residues in the currently widely used chemical control methods. In addition, there are few existing targeted bacterial agent control technologies for gray mold of Eucommia ulmoides leaves.

[0005] In view of this, the present invention is particularly proposed. Summary of the Invention

[0006] The purpose of the present invention is to provide a Pseudomonas viciae, a bacterial agent and their applications in biological control of diseases and plant growth promotion to solve the above technical problems.

[0007] The present invention is implemented as follows:

[0008] In a first aspect, the present invention provides a Pseudomonas viciae, which is deposited with the China General Microbiological Culture Collection Center, address: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, deposit date: November 15, 2024, deposit number: CGMCC No. 32657.

[0009] In a second aspect, the present invention provides a bacterial agent, which comprises the above-mentioned Pseudomonas viciae.

[0010] In a third aspect, the present invention further provides the use of Pseudomonas viciae or the above-mentioned bacterial agent in preventing and controlling plant diseases caused by fungi.

[0011] In a fourth aspect, the present invention further provides the use of Pseudomonas viciae or the above-mentioned bacterial agent in promoting plant growth, and the plants are selected from tomato, pepper, wheat, rice, barley, oats, corn, sorghum, millet, buckwheat, broomcorn millet, sweet potato, potato, cotton, sesame, peanut, sunflower, radish, carrot, eggplant, leek, green onion, onion, leek, spinach, celery, amaranth, lettuce, crown daisy, daylily, grape, strawberry, sugarcane, tobacco, Brassica vegetables, cucurbitaceae plants, leguminous plants, tea, cassava and Chinese herbal medicine plants.

[0012] In a fifth aspect, the present invention further provides a method for promoting plant growth, which comprises the following steps: applying the above-mentioned Pseudomonas viciae or the above-mentioned bacterial agent to plants.

[0013] The present invention has the following beneficial effects:

[0014] By isolating and identifying the pathogenic bacteria of the diseased samples, the present invention finds that the main pathogenic bacteria causing Eucommia ulmoides leaf blight is Botrytis cinerea. The biocontrol bacterium Pseudomonas viciae RD22S4 screened from the rhizosphere soil of Eucommia ulmoides is identified as Pseudomonas by morphological and molecular biological species identification.

[0015] On the one hand, this strain has strong abilities in secreting IAA, protease, siderophore, dissolving organic phosphorus and inorganic phosphorus. On the other hand, this strain has an effective inhibitory effect on the pathogenic fungus Botrytis cinerea of Eucommia leaf blight, and has a broad-spectrum antibacterial effect on pathogenic fungi of rhizosphere diseases of plants such as Fusarium oxysporum of Codonopsis pilosula root rot, Fusarium oxysporum f. sp. cucumerinum of Codonopsis pilosula root rot, Phoma heterosclerotioides of Codonopsis pilosula root rot, Fusarium tricinctum, and Fusarium solani. The RD22S4 strain promotes plant growth by secreting IAA, and provides essential nutrients for plant growth by dissolving organic phosphorus and inorganic phosphorus. By secreting siderophores, it competes with plant pathogenic fungi for iron resources, disrupts the iron homeostasis of the pathogens, thereby reducing the damage of the pathogens to plants, and by secreting siderophores, it is a strategy for its survival in an iron-deficient environment, enabling the bacteria to acquire iron elements and maintain their growth and survival. Therefore, the RD22S4 strain has both growth-promoting and biocontrol functions, can effectively control diseases of various traditional Chinese medicines and crops and promote crop growth, and has good application prospects.

[0016] The Pseudomonas viciae RD22S4 bacterium and the bactericide provided by the present invention have been experimentally proven to be able to effectively control gray mold on pepper fruits, pepper leaves and tomato leaves. Therefore, it also has good application prospects for controlling plant diseases of other plants.

[0017] In addition, the Pseudomonas viciae RD22S4 bacterium, the bactericide and the application provided by the present invention can effectively promote the growth and development of peppers and tomatoes, and can be used to improve the yield and quality of various plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0019] Figure 1 It is the morphological and phylogenetic tree diagram of the Pseudomonas viciae RD22S4 strain; A, colony morphology on LB medium; B, phylogenetic tree of the gene 16S rDNA sequence;

[0020] Figure 2 It is the antagonistic effect diagram of Pseudomonas viciae RD22S4 against Botrytis cinerea (A, front view of the antagonistic effect on 1 / 2 PDA medium; B, back view of the PDA plate of the antagonistic effect);

[0021] Figure 3 Antagonistic effect diagram of Pseudomonas viciae RD22S4 against Fusarium oxysporum on flat confrontation (A, antagonistic effect diagram on 1 / 2 PDA medium; B, colony control diagram of Fusarium oxysporum);

[0022] Figure 4 Antagonistic effect diagram of Pseudomonas viciae RD22S4 against Plectosphaerella cucumerina on flat confrontation (A, front view of antagonistic effect on 1 / 2 PDA medium; B, colony control diagram of Plectosphaerella cucumerina);

[0023] Figure 5 Antagonistic effect diagram of Pseudomonas viciae RD22S4 against Paraphoma ledniceana on flat confrontation (A, front view of antagonistic effect on 1 / 2 PDA medium; B, colony control diagram of Paraphoma chrysanthemicola);

[0024] Figure 6 Antagonistic effect diagram of Pseudomonas viciae RD22S4 against Fusarium tricinctum on flat confrontation (A, front view of antagonistic effect on 1 / 2 PDA medium; B, colony control diagram of Fusarium tricinctum);

[0025] Figure 7 Antagonistic effect diagram of Pseudomonas viciae RD22S4 against Fusarium solani on flat confrontation (A, front view of antagonistic effect on 1 / 2 PDA medium; B, colony control diagram of Fusarium solani);

[0026] Figure 8 Detection result diagram of the ability of Pseudomonas viciae RD22S4 to secrete IAA;

[0027] Figure 9 Detection result diagram of the ability of Pseudomonas viciae RD22S4 to secrete siderophores;

[0028] Figure 10 Detection result diagram of the ability of Pseudomonas viciae RD22S4 to secrete protease;

[0029] Figure 11 Detection result diagram of the ability of Pseudomonas viciae RD22S4 to dissolve organic phosphorus;

[0030] Figure 12 It is a detection result graph of the ability of Pseudomonas viciae RD22S4 to dissolve inorganic phosphorus;

[0031] Figure 13 It is an effect graph of the control of Botrytis cinerea disease on pepper fruits by Pseudomonas viciae RD22S4;

[0032] Figure 14 It is an effect graph of the control of Botrytis cinerea disease on pepper leaves by Pseudomonas viciae RD22S4;

[0033] Figure 15 It is an effect graph of the control of Botrytis cinerea disease on tomato seedlings by Pseudomonas viciae RD22S4;

[0034] Figure 16 It is an effect graph of Pseudomonas viciae RD22S4 promoting the growth of pepper seedlings;

[0035] Figure 17 It is an effect graph of Pseudomonas viciae RD22S4 promoting the growth of tomato seedlings. Detailed implementation manners

[0036] Reference to embodiments of the present invention will now be provided in detail, one or more examples of which are described below. Each example is provided by way of explanation and not limitation of the present invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the scope or spirit of the present invention. For example, features described or illustrated as part of one embodiment can be used in another embodiment to yield a still further embodiment.

[0037] In a first aspect, the present invention provides a Pseudomonas viciae, which is deposited in the General Microbiological Center of the China Committee for Culture Collection of Microorganisms, address: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, deposit date: November 15, 2024, deposit number: CGMCC No. 32657. The name of the biological material submitted for deposit is RD22S4, and the proposed taxonomic name is Pseudomonas viciae. The identification result is viable.

[0038] By isolating and identifying the pathogenic bacteria from the diseased samples, it was found that the main pathogenic bacterium causing Eucommia ulmoides leaf blight is Botrytis cinerea. The biocontrol bacterium Pseudomonas viciae RD22S4 screened from the rhizosphere soil of Eucommia ulmoides was identified as Pseudomonas by morphological and molecular biological species identification.

[0039] On the one hand, this strain has strong abilities of secreting IAA, protease, siderophore, dissolving organic phosphorus and inorganic phosphorus. On the other hand, this strain has an effective inhibitory effect on the pathogenic bacterium Botrytis cinerea of Eucommia ulmoides leaf blight, and has a broad-spectrum antibacterial effect on pathogenic fungi of plant rhizosphere diseases such as Fusarium oxysporum f. sp. codonopsis, Fusarium oxysporum f. sp. cucumerinum, Phoma heterosclerotiorum, Fusarium tricinctum, and Fusarium solani. The RD22S4 strain promotes plant growth by secreting IAA, and provides essential nutrients for plant growth by dissolving organic phosphorus and inorganic phosphorus. By secreting siderophores, it competes with plant pathogenic fungi for iron resources, disrupts the iron homeostasis of the pathogenic bacteria, thereby reducing the damage of the pathogenic bacteria to plants, and by secreting siderophores, it is a strategy for it to survive in an iron-deficient environment, and the bacteria can obtain iron elements to maintain their growth and survival. Therefore, the RD22S4 strain has both growth-promoting and biocontrol functions, can effectively control various Chinese medicinal materials and crop diseases and promote crop growth, and has good application prospects.

[0040] Studies have shown that plant growth-promoting rhizobacteria (PGPR) are beneficial bacteria that can stably survive in the rhizosphere or on the root surface and can secrete various secondary metabolites to directly or indirectly promote plant growth and prevent and control diseases. The promotion of plant growth by PGPR is mainly reflected in promoting plant growth by secreting secondary metabolites such as the plant growth hormone 3-indoleacetic acid (IAA) and siderophores. Therefore, the RD22S4 strain also belongs to plant growth-promoting rhizobacteria and has both biocontrol and growth-promoting functions of promoting plant growth and preventing plant diseases.

[0041] Second, the present invention provides a bacterial agent, which includes the above-mentioned Pseudomonas viciae. The bacterial agent is, for example, prepared by diluting the fermentation product.

[0042] It includes, but is not limited to, being obtained by solid fermentation or liquid fermentation of the above-mentioned Pseudomonas viciae. The bacterial agent includes, but is not limited to, at least one of concentrate, paste, dry matter, liquid matter, diluent and crushed matter of Pseudomonas viciae. The dry matter includes, but is not limited to, spray-dried matter, freeze-dried matter, vacuum-dried matter, drum-dried matter, etc.

[0043] In a third aspect, the present invention also provides the use of Pseudomonas viciae or the above-mentioned bacterial agent in preventing and controlling plant diseases caused by fungi.

[0044] Pseudomonas viciae competes with plant pathogenic fungi for iron resources by secreting siderophores, disrupting the iron homeostasis of the pathogen, thereby reducing the damage of the pathogen to plants. And secreting siderophores is a strategy for it to survive in an iron-deficient environment. Bacteria can obtain iron elements to maintain their growth and survival. Therefore, Pseudomonas viciae or the bacterial agent provided by the present invention has good application prospects in preventing and controlling plant diseases caused by fungi.

[0045] In a preferred embodiment of the application of the present invention, the fungal diseases are selected from plant diseases caused by at least one of Botrytis cinerea, Fusarium oxysporum, Plectosphaerella cucumerina, Paraphoma ledniceana, Fusarium tricinctum, and Fusarium solani.

[0046] The antibacterial results show that Pseudomonas viciae provided by the present invention exhibits high antibacterial effects against Botrytis cinerea, Fusarium oxysporum, Plectosphaerella cucumerina, Paraphoma ledniceana, Fusarium tricinctum, and Fusarium solani. Therefore, Pseudomonas viciae and its bacterial agent provided by the present invention can prevent and control plant diseases caused by at least one of Botrytis cinerea, Fusarium oxysporum, Plectosphaerella cucumerina, Paraphoma ledniceana, Fusarium tricinctum, and Fusarium solani.

[0047] In a preferred embodiment of the application of the present invention, the plant is selected from tomato, pepper, wheat, rice, barley, oats, corn, sorghum, millet, buckwheat, broomcorn millet, sweet potato, potato, cotton, sesame, peanut, sunflower, radish, carrot, eggplant, leek, scallion, onion, leek, spinach, celery, amaranth, lettuce, crown daisy, daylily, grape, strawberry, sugarcane, tobacco, cruciferous vegetables, cucurbit plants, leguminous plants, tea, cassava and Chinese herbal medicine plants;

[0048] In a preferred embodiment of the application of the present invention, the Chinese herbal medicine plant is selected from codonopsis pilosula, eucommia ulmoides, scutellaria baicalensis, cannabis, isatis root, astragalus membranaceus, honeysuckle, forsythia suspensa, phellodendron amurense, coptis chinensis, polygonum cuspidatum, gardenia jasminoides, paris polyphylla, bupleurum chinense, isatis root, dandelion, cortex lycii radicis, anemarrhena asphodeloides, rehmannia glutinosa, scrophularia ningpoensis, sterculia lychnophora, sargentodoxa cuneata, radix paeoniae rubra, pulsatilla chinensis and cortex moutan.

[0049] Pseudomonas viciae or the bacterial agent is used for preventing and controlling the gray mold disease of plants caused by fungi.

[0050] In a preferred embodiment of the application of the present invention, the application includes the following application methods: Pseudomonas viciae secretes siderophores. By secreting siderophores, it competes with plant pathogenic fungi for iron resources, disrupts the iron homeostasis of the pathogen, and thus reduces the invasion of the pathogen to the plant.

[0051] Fourthly, the present invention also provides the application of Pseudomonas viciae or the above-mentioned bacterial agent in promoting plant growth. The plant is selected from tomato, pepper, wheat, rice, barley, oats, corn, sorghum, millet, buckwheat, broomcorn millet, sweet potato, potato, cotton, sesame, peanut, sunflower, radish, carrot, eggplant, leek, scallion, onion, leek, spinach, celery, amaranth, lettuce, crown daisy, daylily, grape, strawberry, sugarcane, tobacco, cruciferous vegetables, cucurbit plants, leguminous plants, tea, cassava and Chinese herbal medicine plants;

[0052] In a preferred embodiment of the application of the present invention, the Chinese herbal medicine plant is selected from codonopsis pilosula, eucommia ulmoides, scutellaria baicalensis, cannabis, isatis root, astragalus membranaceus, honeysuckle, forsythia suspensa, phellodendron amurense, coptis chinensis, polygonum cuspidatum, gardenia jasminoides, paris polyphylla, bupleurum chinense, isatis root, dandelion, cortex lycii radicis, anemarrhena asphodeloides, rehmannia glutinosa, scrophularia ningpoensis, sterculia lychnophora, sargentodoxa cuneata, radix paeoniae rubra, pulsatilla chinensis and cortex moutan.

[0053] In a preferred embodiment of the application of the present invention, the application includes the following application methods:

[0054] (1) Pseudomonas viciae secretes IAA;

[0055] (2) Pseudomonas viciae secretes siderophores;

[0056] (3) Pseudomonas viciae dissolves inorganic phosphorus;

[0057] (4) Pseudomonas viciae dissolves organic phosphorus;

[0058] (5) Pseudomonas fabae secretes protease.

[0059] In a preferred embodiment of the application of the present invention, the application includes at least one of the following application methods:

[0060] (1) Used as a root drench;

[0061] (2) Used as a seed soaking agent;

[0062] (3) Used as a foliar spray;

[0063] In a preferred embodiment of the application of the present invention, promoting plant growth includes at least one of the following applications:

[0064] (1) Increasing the fresh weight of plants;

[0065] (2) Increasing the dry weight of plants;

[0066] (3) Increasing the plant height.

[0067] Fresh weight refers to the weight of an organism or cell in its natural state, including all the water and other components within the cell. Dry weight refers to the weight of an organism or cell after removing all free water.

[0068] In a preferred embodiment of the application of the present invention, the use concentration of Pseudomonas fabae is 1×10 5 -1×10 8 CFU / mL. The actual use concentration can be adjusted according to needs, such as dilution or concentration. For example, the use concentration is 1×10 5 CFU / mL, 2×10 5 CFU / mL, 3×10 5 CFU / mL, 4×10 5 CFU / mL, 5×10 5 CFU / mL, 6×10 5 CFU / mL, 7×10 5 CFU / mL, 8×10 5 CFU / mL, 9×10 5 CFU / mL, 1×10 6 CFU / mL, 2×10 6 CFU / mL, 3×10 6 CFU / mL, 4×10 6 CFU / mL, 5×10 6 CFU / mL, 8×10 6 CFU / mL, 9×10 6CFU / mL, 1×10 7 CFU / mL, 4×10 7 CFU / mL, 5×10 7 CFU / mL, 1×10 8 CFU / mL.

[0069] In a preferred embodiment of the application of the present invention, at least one of a surfactant, a binder, a stabilizer, a pH regulator, a protective agent, an excipient, a disintegrant, a lubricant, a fragrance, a preservative, a suspending agent, a dispersing agent, and a diluent is further added to the root irrigation agent, the seed soaking agent, or the foliar spraying agent.

[0070] Examples include: surfactants such as Tween 20, Tween 80, etc.; pH regulators such as disodium hydrogen phosphate, dipotassium hydrogen phosphate, etc.; excipients such as sucrose, starch, mannitol, sorbitol, lactose, glucose, cellulose, talc, calcium phosphate, calcium carbonate; binders such as cellulose, methylcellulose, hydroxypropylcellulose, polypropylpyrrolidone, gelatin, gum arabic, polyethylene glycol, sucrose, starch; disintegrants such as starch, hydrolyzed starch, carboxymethylcellulose, calcium carboxymethylcellulose, hydroxypropyl starch, sodium glycol starch, sodium bicarbonate, calcium phosphate, calcium citrate; lubricants such as magnesium stearate, talc, sodium lauryl sulfate; fragrances such as citric acid, menthol, glycine, orange powder; preservatives such as sodium benzoate, sodium bisulfite, parabens (such as methyl paraben, ethyl paraben, propyl paraben, butyl paraben); stabilizers such as citric acid, sodium citrate, acetic acid, and polycarboxylic acids from the titriplex series such as diethylenetriaminepentaacetic acid (DTPA); suspending agents such as methylcellulose, polyvinylpyrrolidone, aluminum stearate; dispersing agents; diluents such as water, organic solvents; waxes, fats, and oils such as beeswax, cocoa butter; polyethylene glycol; white petrolatum, etc.

[0071] When used as a root irrigation agent, the timing of root irrigation includes but is not limited to the seedling stage, the mature stage, etc. When used as a seed soaking agent, it includes but is not limited to soaking the seeds of plants and then sowing. In an alternative embodiment, Pseudomonas fabae can be attached to the surface of the seeds as a component of the seed coating, for example, as a filler of the seed coating. When used as a foliar spraying bacterium, a foliar spraying agent including Pseudomonas fabae can be sprayed onto the leaf surface or fruit surface of the target plant.

[0072] Fifthly, the present invention also provides a method for promoting plant growth, which includes the following steps: applying the above-mentioned Pseudomonas fabae or the above-mentioned bacterial agent to plants;

[0073] In a preferred embodiment of the application of the present invention, Pseudomonas viciae is used for root irrigation, seed soaking of plants, or spraying on the leaves, stems or fruits of plants.

[0074] The Pseudomonas viciae or the above-mentioned microbial agent provided by the present invention can increase the plant height, fresh weight and dry weight of plant seedlings, and can effectively promote the growth of plant seedlings. Especially for peppers and tomatoes.

[0075] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. For those not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are followed. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained by purchasing in the market.

[0076] The features and properties of the present invention will be further described in detail below in conjunction with the embodiments.

[0077] Example 1

[0078] In this example, the isolation and identification of Pseudomonas viciae are carried out.

[0079] 1. Sample source

[0080] In 2021, disease investigations and samplings were carried out in Jinjiahe, Lueyang County, Hanzhong (33°20'01.6"N, 105°59'10.9"E), the main production area of Eucommia ulmoides in China. 5 diseased plants and leaves, 5 healthy seedlings and 5 rhizosphere soils were collected in the Eucommia ulmoides planting area. The whole area where the diseased plants were located was infected, and the healthy samples were taken from adjacent areas. The method for collecting rhizosphere soil was to shake off the soil on the root surface and gently brush it with a disinfected toothbrush. It was transported back to the laboratory in a sampling box equipped with ice packs on the same day and immediately stored in a 4°C refrigerator for the separation of fungal pathogens and antagonistic bacteria.

[0081] 2. Source of the pathogen Botrytis cinerea of Eucommia ulmoides leaves

[0082] The pathogen Botrytis cinerea causing Eucommia ulmoides leaf blight was isolated from the diseased leaves of Eucommia ulmoides showing typical leaf blight symptoms. At the junction of the diseased area and the healthy area, leaf samples were surface-sterilized, i.e., rinsed twice with sterile water, soaked in 75% absolute ethanol for 30 s, rinsed twice with sterile water, soaked in 3% sodium hypochlorite for 5 minutes, and rinsed three times with sterile water. The surface-sterilized sample materials were cut into small pieces (each about 1×0.5 inches in size) with a sterile blade. Every three small pieces were placed on Rose Bengal agar medium, which was prepared by mixing 5 g peptone, 10 g glucose, 1 g potassium dihydrogen phosphate, 0.5 g magnesium sulfate, 0.033 g Rose Bengal, 0.1 g chloramphenicol, and 15 g agar per liter. After culturing at 25°C for 5 - 7 days, mycelia were taken from the edge of the primary colonies and placed on PDA plates for further purification. After obtaining the purified fungi, through morphological and molecular biological identification, as well as pathogenicity re-inoculation experiments, it was verified that the pathogen causing Eucommia ulmoides leaf blight was Botrytis cinerea.

[0083] 3. Isolation and culture of antagonistic bacteria in the rhizosphere of Eucommia ulmoides

[0084] To isolate antagonistic bacteria against Botrytis cinerea causing Eucommia ulmoides leaf blight, rhizosphere soil samples were collected from healthy 2-year-old trees in adjacent planting areas. Five rhizosphere soil samples were mixed with four gradient dilutions (10 2 , 10 3 , 10 4 ) of the soil and cultured in R2A medium (0.5 g peptone, 0.3 g potassium dihydrogen phosphate, 0.5 g casein, 0.5 g soluble starch, 0.5 g yeast extract, 0.5 g glucose, 0.5 g magnesium sulfate heptahydrate, 0.3 g sodium pyruvate, adding 15 g agar per liter of ultrapure water, adjusting the volume to 1 L with distilled water, and adjusting the pH to 7.2) at 30°C for 2 - 5 days. After three purification processes, duplicates were removed according to the morphology and characteristics of the newly grown colonies. All 29 isolated strains, except those that could not be further subcultured, were stored in 40% glycerol at -80°C.

[0085] Antagonistic bacteria against Botrytis cinerea causing Eucommia ulmoides leaf blight were screened from numerous bacteria isolated from the rhizosphere of Eucommia ulmoides. The antagonistic bacterial strains were inoculated into liquid LB medium and cultured with shaking for 48 hours. The precipitated bacterial cells were centrifuged at 5000 rpm for 5 minutes and resuspended with an equal volume of sterile water. After the pathogenic fungus Botrytis cinerea had grown on a 1 / 2 PDA plate for 10 days, a small amount of mycelium was inoculated in the center of a new 1 / 2 PDA plate. Then, 5 μL of the bacterial suspension was added dropwise to each of the four symmetrically spaced points of the cross. Sterile water was used as a control. The colony radius of Botrytis cinerea on these antagonistic assay plates was measured after culturing at 25 °C for 5 days using ImageJ v.1.53a (NIH) software. The fungal growth inhibition rate (PFGI) was calculated using the formula: PFGI = (R1 - R2) / R1 * 100%. R1 represents the average diameter of the mycelium in the blank test, and R2 is the diameter of the inhibited bacterial cells.

[0086] The antagonistic effect of Pseudomonas viciae RD22S4 against Botrytis cinerea in the plate confrontation assay was referred to Figure 2 as shown Figure 2 in which A is the front view of the antagonistic effect on a 1 / 2 PDA medium; Figure 2 and B in

[0087] is the back view of the PDA plate of the antagonistic effect. The results showed that the screened Pseudomonas viciae RD22S4 had a high antagonistic effect against Botrytis cinerea. 6 -10 8 CFU / mL.

[0088] Using the above-mentioned Pseudomonas viciae RD22S4 bacterial agent or bacterial liquid as the active ingredient, in the plate co-culture confrontation test on a PDA plate, the growth inhibition rate of Botrytis cinerea causing Eucommia ulmoides leaf blight was 47.5%.

[0089] 4. Observation of the colony morphological characteristics of RD22S4

[0090] The single colony of RD22S4 was streaked on LB agar medium (10 g sodium chloride, 10 g peptone, 5 g yeast extract, made up to 1 L with distilled water). After sealing with parafilm, it was placed in an incubator at 30 °C for 48 h and then taken out. The characteristics such as the morphology, color and texture of the single colony were observed. The observation results showed that the single colony of RD22S4 on LB medium was light yellow, with a smooth and moist surface, specifically as shown in Figure 1 shown in A below.

[0091] 5. 16S rDNA gene sequence and phylogenetic identification of RD22S4 bacteria.

[0092] A single colony of the purified RD22S4 bacterial strain was picked and cultured overnight at 30 °C with a rotation speed of 180 rpm in LB liquid medium. After centrifugation at 10000 rpm for 2 minutes, the bacterial cells were collected. Using the EZ-10 Column Bacterial Genomic DNA Extraction Kit (Shanghai Sangon Biotech Co., Ltd.), according to the steps in the instruction manual, the genomic DNA of the bacterial cells of this strain was extracted. Using the obtained DNA as a template, the universal primers 27F (5’-AGAGTTTGATCCTGGCTCAG-3’) and 1492R (5’-GGTTACCTTGTTACGACTT-3’) for bacterial 16S rDNA gene were used for PCR amplification. The amplification conditions were 93 °C for 4 minutes; 30 cycles: 94 °C for 30 seconds, 48 °C for 15 seconds, 72 °C for 1 minute; 72 °C for 10 minutes. The PCR products were detected by 1% agarose gel electrophoresis for their amplification quality. Subsequently, the products were sent to Shanghai Sangon Biotech Co., Ltd. for Sanger bidirectional sequencing.

[0093] The Seqman software was used to splice the gene sequences obtained from the bidirectional sequencing. The 16S rDNA nucleotide sequence of the RD22S4 bacterial strain obtained was as shown in SEQ ID NO.1, with a length of 1383 bp. The spliced sequence was uploaded to the NCBI database and Blastn alignment similarity was performed to obtain related sequences. These sequences were aligned using Align and the Mega11 software, and then the neighbor-joining method was used to construct a phylogenetic tree. The results were as shown in Figure 1As shown in B. The 16S rDNA related sequence of strain RD22S4 is Pseudomonas viciae (NR_180948), with a similarity of 100%. Therefore, this strain RD22S4 belongs to the genus Pseudomonas viciae and was deposited on November 15, 2024 at the China General Microbiological Culture Collection Center (CGMCC). The deposit address is: Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing. The deposit name is Pseudomonas viciae RD22S4, and the deposit number is: CGMCC No. 32657.

[0094] The following is the result of sequencing sequence splicing (as shown in SEQ ID NO.1):

[0095]

[0096] Example 2

[0097] This example provides an inhibition experiment on the mycelial growth of Pseudomonas viciae RD22S4 against Fusarium oxysporum, Plectosphaerella cucumerina, Paraphoma ledniceana, Fusarium tricinctum, and Fusarium solani in Codonopsis pilosula roots. Using the bacterial agent or bacterial liquid of Pseudomonas viciae RD22S4 screened in Example 1 above as the active ingredient, a co-culture confrontation test was conducted with the above-mentioned various pathogenic bacteria on a PDA plate.

[0098] The specific steps are as follows:

[0099] 1. Source of pathogenic bacteria

[0100] Fusarium oxysporum was isolated from the roots of Codonopsis pilosula with black root rot (published in the literature [First report of root rot caused by the Fusarium oxysporum species complex on Codonopsis pilosula in China, Zhao Xia et al., Plant Disease. 105.11: 3742. 2021]), Plectosphaerella cucumerina and Paraphoma ledniceana were isolated from the diseased roots of Codonopsis pilosula (published in the literature [Continuous monoculture alters the fungal community and accumulates potential pathogenic strains in the rhizosphere of Codonopsis pilosula. Zhao Xia et al., Phytobiomes Journal: PBIOMES - 11, 2024]), Fusarium tricinctum and Fusarium solani preserved in this laboratory.

[0101] 2. Test on the inhibitory activity of the antagonistic bacterium Pseudomonas viciae RD22S4 against multiple pathogenic fungi of Codonopsis pilosula.

[0102] The antagonistic bacterium Pseudomonas viciae RD22S4 strain was inoculated into liquid LB medium and cultured with shaking for 48 hours. The precipitated bacteria were centrifuged at 5000 rpm for 5 minutes and resuspended with an equal volume of sterile water. After the five pathogenic fungi, Fusarium oxysporum f. sp. codonopsis, Fusarium oxysporum f. sp. cucumerinum, Phomopsis heterocerus, Fusarium tricinctum, and Fusarium solani, grew on 1 / 2 PDA plates for 3 days and 7 days respectively, a small amount of mycelium was inoculated in the center of a new 1 / 2 PDA plate. Then, 5 μL of the RD22S4 bacterial solution was added dropwise to each of the four symmetrically spaced points of the cross. Sterile water was used as a control. These antagonistic assay plates were incubated at 25°C for 6 days, 9 days, 7 days, and 30 days respectively and observed. The results showed that Pseudomonas viciae RD22S4 had antibacterial effects against Fusarium oxysporum f. sp. codonopsis ( Figure 3 ), Fusarium oxysporum f. sp. cucumerinum ( Figure 4 ), Phomopsis heterocerus ( Figure 5 ), Fusarium tricinctum ( Figure 6 ), and Fusarium solani ( Figure 7 ).

[0103] Example 3

[0104] In this example, a growth promotion experiment was conducted on Pseudomonas viciae RD22S4. A plant growth-promoting bacterium agent was provided, and it was found that the bacterium agent or bacterial solution of Pseudomonas viciae RD22S4 mentioned above as the active ingredient had the potential ability to promote plant growth by secreting IAA, siderophores, protease, and dissolving organic phosphorus and inorganic phosphorus.

[0105] 1. Determination of the ability to secrete IAA.

[0106] A single colony of Pseudomonas viciae RD22S4 was picked into 1 mL of LB liquid medium and cultured with shaking at 180 rpm at 30°C for 24 hours for activation. 10 μL of the activated RD22S4 bacterial solution was pipetted into LB liquid medium containing 200 mg / L of L-tryptophan and incubated at 180 rpm in a shaker at 30°C for 4 days. Then, 50 μL of the bacterial solution was dropped into the depression of a white ceramic plate, and then 50 μL of Salkowski colorimetric solution (Salkowski colorimetric solution preparation: 50 mL of 30% HClO4, 1 mL of 0.5 mol / L FeCl3) was added for color reaction. 50 μL of colorimetric solution containing 50 mg / L of IAA was used as a positive control. 50 μL of the un-inoculated liquid LB medium was used as a negative control. The ceramic plate was placed in the dark for color development for 30 minutes. If the color turned red, it indicated that the strain had the ability to produce IAA.

[0107] The test results were asFigure 8 As shown, the reaction solution inoculated with Pseudomonas viciae RD22S4 bacteria showed an obvious red color, indicating that the RD22S4 bacteria have the ability to produce IAA.

[0108] 2. Determination of the ability to produce siderophores.

[0109] Pipette 10 μL of the above-activated RD22S4 bacterial solution and drop it on the surface of a CAS solid medium (CAS medium preparation: Dissolve 0.59 g of disodium hydrogen phosphate dihydrate, 2.43 g of dodecahydrate disodium hydrogen phosphate, 0.25 g of ammonium chloride, 0.075 g of potassium dihydrogen phosphate, and 0.125 g of sodium chloride in 100 mL of phosphate solution; Mix 6.04 g of PIPES with 100 mL of phosphate solution, adjust the pH to 6.8 with 50% NaOH solution, add 3.2 g of agar powder, and sterilize at 121 °C for 15 min; 1 mmol / L CaCl2 solution, 1 mmol / L magnesium sulfate tetrahydrate, 10% acid-hydrolyzed casein, 20% glucose solution, sterilize at 121 °C for 15 min; At 60 °C, add 0.2 mL of calcium chloride, 4 mL of magnesium sulfate heptahydrate, 2 mL of glucose, and 6 mL of acid-hydrolyzed casein solution). After the plate inoculated with RD22S4 bacteria was statically cultured in an incubator at 37 °C for 48 hours, observe whether there is an obvious orange-yellow transparent zone around the colony. The presence or absence of the transparent zone can reflect whether the strain has the ability to produce siderophores.

[0110] The detection results are as Figure 9 shown, indicating that Pseudomonas viciae RD22S4 bacteria have the ability to produce siderophores.

[0111] 3. Determination of the ability to secrete protease.

[0112] Pipette 10 μL of the activated RD22S4 bacterial solution in the above example and drop it on the surface of a 90-mm-diameter plate containing skim milk powder medium (skim milk powder medium preparation: 3.0 g of skim milk powder, 15 g of agar powder, 1 L of distilled water, pH = 7.0 - 7.2, sterilize at 120 °C for 20 min). After the plate inoculated with RD22S4 bacteria was statically cultured in an incubator at 30 °C for 48 hours, observe whether there is a transparent zone around the colony. The presence or absence of the transparent zone reflects whether the strain has the ability to produce protease.

[0113] The detection results are referred to Figure 10 as shown, and the results show that Pseudomonas viciae RD22S4 bacteria have good protease-producing ability.

[0114] 4. Determination of the ability to dissolve organic phosphorus.

[0115] A single colony of RD22S4 was picked and cultured in LB liquid medium at 30 °C with shaking at 180 rpm overnight for activation. 10 μL of the activated bacterial liquid was aspirated and dropped onto the surface of a solid organic phosphorus medium (the organic phosphorus medium was prepared as follows: 10 g of glucose, 0.5 g of ammonium sulfate, 0.3 g of magnesium sulfate heptahydrate, 0.03 g of manganese sulfate tetrahydrate, 0.3 g of potassium chloride, 0.03 g of ferrous sulfate heptahydrate, 0.3 g of sodium chloride, 5.0 g of calcium carbonate, 0.2 g of lecithin, 15 g of agar powder, 1 L of distilled water, sterilized at 121 °C for 20 min, pH = 7.0). It was cultured statically at 30 °C. After 2 to 4 days, observe whether there is a transparent circular area around the colony to determine whether the strain can dissolve organic phosphorus.

[0116] The detection results are as Figure 11 shown. There is an obvious transparent halo around the colony of RD22S4. Therefore, Pseudomonas viciae RD22S4 is considered to have the ability to dissolve organic phosphorus.

[0117] 5. Determination of the ability to dissolve inorganic phosphorus.

[0118] A single colony of RD22S4 was picked and cultured in LB liquid medium at 30 °C with shaking at 180 rpm overnight for activation. 10 μL of the above-activated RD22S4 bacterial liquid was aspirated and dropped onto the surface of a solid inorganic phosphorus medium (the inorganic phosphorus medium was prepared as follows: 10 g of glucose, 0.5 g of ammonium sulfate, 0.3 g of magnesium sulfate heptahydrate, 0.03 g of manganese sulfate tetrahydrate, 0.3 g of potassium chloride, 0.03 g of ferrous sulfate heptahydrate, 0.3 g of sodium chloride, 10 g of calcium phosphate, 15 g of agar powder, 1 L of distilled water, pH = 7.0). It was cultured statically at 30 °C. After 2 to 4 days, observe and record whether there is a transparent halo around the colony to determine whether the strain can dissolve inorganic phosphorus.

[0119] The detection results are as Figure 12 shown. There is an obvious transparent halo around the colony of RD22S4. Therefore, it shows that Pseudomonas viciae RD22S4 has the ability to dissolve inorganic phosphorus.

[0120] Example 4

[0121] In this example, an experiment on preventing and controlling Botrytis cinerea disease of pepper fruits was carried out with the RD22S4 bacterial agent. Spraying the above-mentioned broad-spectrum antibacterial agent RD22S4 bacterial agent and the fungal plug inoculated with Botrytis cinerea on the wounds of pepper fruits can effectively reduce the incidence of Botrytis cinerea disease of pepper fruits.

[0122] 1. Preparation of the RD22S4 bacterial agent.

[0123] The activated RD22S4 bacterial solution in the above-mentioned example was transferred to 50 mL of liquid LB medium for activation and cultured in a shaker at 37 °C at 180 rpm for 48 hours. The cultured bacterial solution was centrifuged at 8000 g for 5 min, the supernatant was discarded, and the precipitated bacteria were collected. Then, they were resuspended with 50 mL of sterile water to prepare an RD22S4 bacterial agent, and the viable bacteria count was detected under a microscope to be 1×10 6 -1×10 7 CFU / mL.

[0124] 2. Control of Botrytis cinerea on pepper fruits.

[0125] The pepper fruits were soaked in 1% (v / v) sodium hypochlorite solution for 2 minutes and then rinsed 3 times in sterile distilled water. Then, the above-mentioned RD22S4 biocontrol bacterial solution was sprayed with a sterilized sterile sprayer, and 0.3 mL was sprayed on each pepper fruit in the experimental group. The control group was sprayed with 0.3 mL of sterile water. After drying, a sterile pipette tip was used to make vertical wounds at the tip, center, and bottom of each pepper fruit. Discs with a diameter of about 3 mm were cut from the mycelia of Botrytis cinerea cultured on PDA medium for 14 days, and the mycelia were attached to the wound sites with the mycelia facing downwards. The treated fruits were placed in a sterilized plastic box and placed in an incubator at about 24 °C and 100% relative humidity for 5 days, and the results were observed and recorded. Also, the number of diseased sites on the inoculated parts of the pepper fruit surface was counted, and the control effect of the Pseudomonas viciae RD22S4 bacterial agent on pepper gray mold was quantitatively analyzed using the calculation formula of the number of diseased sites / the total number of inoculated sites × 100% = disease incidence (%).

[0126] According to Figure 13 The results showed that the Pseudomonas viciae RD22S4 biocontrol bacterial agent could inhibit Botrytis cinerea on pepper fruits. Table 1 shows that the disease incidence of pepper fruits after inoculation with the Pseudomonas viciae RD22S4 biocontrol bacterial agent was significantly reduced compared with the control. Compared with 74.11% of the control group for the disease incidence of pepper fruits, the disease incidence of the group sprayed with the Pseudomonas viciae RD22S4 biocontrol bacterial agent decreased to 19.00%, and the relative control effect reached 74.32%. The above results indicate that the Pseudomonas viciae RD22S4 biocontrol bacterial agent has a good inhibitory effect on Botrytis cinerea on pepper fruits and can effectively control Botrytis cinerea on pepper fruits.

[0127] Table 1. Control effect of Pseudomonas viciae RD22S4 bacterial agent on Botrytis cinerea of pepper fruits

[0128]

[0129] Example 5

[0130] This embodiment provides a control method for preventing and controlling Botrytis cinerea on the leaves of pepper and tomato seedlings with the RD22S4 biocontrol agent. It includes spraying the above-mentioned RD22S4 biocontrol agent on the leaves of pepper and tomato, as well as inoculating Botrytis cinerea plugs on pepper seedlings and spraying spore suspension on tomato seedlings, all of which can effectively reduce the incidence of Botrytis cinerea on the leaves of pepper and tomato.

[0131] The specific steps are as follows:

[0132] 1. Preparation of pathogen spore suspension.

[0133] Add 20 mL of sterile water to the PDA plate of Botrytis cinerea cultured for 30 days, gently brush with a sterile toothbrush, filter the mixture of spores and hyphae through a sterile four-layer cotton gauze to obtain a spore suspension, detect it with a microscope, and adjust the concentration to 1×10 5 -1×10 6 spores / mL to make the pathogen spore suspension.

[0134] 2. Application of control of Botrytis cinerea on pepper and tomato seedlings.

[0135] Spray the above-mentioned RD22S4 biocontrol solution on pepper and tomato seedlings respectively. Each seedling in the experimental group is sprayed with 0.5 mL (containing 0.2% Tween 20). Each seedling in the control group is sprayed with 0.3 mL of sterile water (containing 0.2% Tween 20). After the water stains on the pepper leaf surface are dried, punch a disk with a diameter of about 3 mm from the Botrytis cinerea hyphae cultured on the PDA medium for 14 days, and stick the hyphae downward on the surface of the pepper leaf. After the water stains on the tomato leaf surface are dried, spray the above-mentioned pathogen spore suspension on the tomato leaf surface. Each seedling is sprayed with 0.5 mL of spore suspension and left standing until the water stains on the leaf surface are dried. Place the treated pepper and tomato seedlings in a greenhouse at about 24°C and a relative humidity of more than 70%, record the wilting of the seedling leaves, and conduct statistics on the leaf incidence.

[0136] According to Figure 14 and Figure 15The results showed that the biocontrol agent RD22S4 could inhibit the gray mold disease on the leaves of peppers and tomatoes. According to the statistical results of the incidence rate in Table 2, compared with the control, the incidence rate of gray mold on peppers and tomatoes significantly decreased after inoculation with the biocontrol agent RD22S4. For the incidence rate of gray mold on pepper leaves, compared with 67.01% in the control group, the incidence rate decreased to 35.83% after spraying the biocontrol agent RD22S4, and the relative control effect reached 46.53%; for the incidence rate of gray mold on tomato leaves, compared with 88.83% in the control group, the incidence rate decreased to 58.33% after spraying the biocontrol agent RD22S4, and the relative control effect reached 34.34%. The above results indicate that the biocontrol agent Pseudomonas viciae RD22S4 has a good inhibitory effect on the gray mold pathogen on the leaves of peppers and tomatoes and can effectively control the gray mold of peppers and tomatoes.

[0137] Table 2. Control effect of Pseudomonas viciae RD22S4 agent on gray mold of pepper and tomato leaves

[0138]

[0139] Example 6

[0140] The present invention also provides a method for promoting the growth of pepper and tomato seedlings, which includes inoculating the agent RD22S4 into the soil at the roots of potted pepper and tomato seedlings, increasing the plant height, fresh weight and dry weight of pepper and tomato seedlings, and effectively promoting the growth of pepper and tomato seedlings.

[0141] Using seed sowing, thinning or filling seedlings after emergence to ensure that there are 3 seedlings in each hole (9 cm × 9 cm) of the seedling tray. Conduct the above-mentioned inoculation treatment of the agent RD22S4 on 30-day-old pepper and tomato seedlings, mainly adopting the root irrigation inoculation method. In the experimental group, 1 mL of the agent RD22S4 was inoculated at the rhizosphere of each seedling, and the second inoculation of the agent was carried out after one week, with tap water inoculation as the control group. Observe and record the growth of peppers and tomatoes 30 days after inoculation, and statistically analyze the plant height and fresh weight of each seedling. After the harvested seedlings are air-dried in an envelope bag at room temperature for 14 days, the dry weight is measured. The plant height is measured using ImageJ software, and the data is statistically analyzed using spss 18 software. The significance of the differences in various parameters (fresh weight, dry weight, plant height) between inoculating RD22S4 and the control group is tested by one-way ANOVA (Duncan method, P < 0.05).

[0142] According to Figure 16 (pepper) and Figure 17The results of (tomato) showed that the growth-promoting bacterium agent RD22S4 could significantly increase the growth of peppers and tomatoes. According to the statistics of the plant height, fresh weight, and dry weight of peppers and tomatoes in Table 3, compared with the average plant heights of 13.54 cm and 23.73 cm in the control group, the average plant heights increased to 15.18 cm and 31.01 cm after inoculation with the growth-promoting bacterium agent RD22S4; compared with the average fresh weights of 0.78 g and 2.86 g in the control group, the average fresh weights increased to 1.09 g and 3.76 g after inoculation with the growth-promoting bacterium agent RD22S4; compared with the average dry weights of 0.09 g and 0.23 g in the control group, the average dry weights increased to 0.14 g and 0.33 g after inoculation with the growth-promoting bacterium agent RD22S4. The above results indicate that the growth-promoting bacterium agent Pseudomonas viciae RD22S4 has a good application effect in promoting the growth and development of peppers and tomatoes.

[0143] Table 3. The application of Pseudomonas viciae RD22S4 bacterium agent increased the plant height, fresh weight, and dry weight of tomato seedlings.

[0144]

[0145] Note: The data in the table are the mean ± standard error per seedling. Different letters indicate significant differences at the P < 0.05 level by Duncan's test.

[0146] In summary, a biocontrol bacterium Pseudomonas viciae RD22S4 screened from the rhizosphere soil of Eucommia ulmoides was identified as Pseudomonas by morphological and molecular biological species identification. On the one hand, this strain has strong abilities to secrete IAA and protease, produce siderophores, dissolve organic phosphorus and inorganic phosphorus. On the other hand, this strain has an effective inhibitory effect on the pathogen Botrytis cinerea of Eucommia ulmoides leaf blight, and has a broad-spectrum antibacterial effect on pathogenic fungi of plant rhizosphere diseases such as Fusarium oxysporum of Codonopsis pilosula root rot, Fusarium oxysporum f. sp. cucumerinum of Codonopsis pilosula root rot, Phoma heterosclerotiorum of Codonopsis pilosula root rot, Fusarium tricinctum, and Fusarium solani. The RD22S4 strain promotes plant growth by secreting IAA, provides essential nutrients for plant growth by dissolving organic phosphorus and inorganic phosphorus. By secreting siderophores, it competes with plant pathogenic fungi for iron resources, disrupts the iron homeostasis of the pathogen, thereby reducing the damage of the pathogen to plants, and by secreting siderophores, it is a strategy for its survival in an iron-deficient environment, and the bacteria can obtain iron elements to maintain their growth and survival. Therefore, the RD22S4 strain has both growth-promoting and biocontrol functions, can effectively control various Chinese medicinal materials and crop diseases and promote crop growth, and has good application prospects.

[0147] The Pseudomonas viciae RD22S4 bacterium, the bacterial agent and the application provided by the present invention can effectively control Botrytis cinerea on chili fruits, chili leaves and tomato leaves, and have good application prospects for controlling plant diseases.

[0148] In addition, the Pseudomonas viciae RD22S4 bacterium, the bacterial agent and the application provided by the present invention can effectively promote the growth and development of chili peppers and tomatoes, and can improve the yield and quality of various plants.

[0149] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A Pseudomonas viciae, characterized in that, It is preserved in the General Microbiological Center of the China General Microbiological Culture Collection Center, Address: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, Preservation Date: November 15, 2024, Preservation Number: CGMCC No. 32657.

2. A bacterial agent, characterized in that, It includes the Pseudomonas viciae described in claim 1.

3. Use of the Pseudomonas viciae according to claim 1 or the bacterial agent according to claim 2 in controlling plant diseases caused by fungi.

4. The application according to claim 3, characterized in that, The fungal diseases are selected from plant diseases caused by at least one of Botrytis cinerea, Fusarium oxysporum, Plectosphaerella cucumerina, Paraphoma ledniceana, Fusarium tricinctum, and Fusarium solani; Preferably, the plants are selected from tomato, pepper, wheat, rice, barley, oats, corn, sorghum, millet, buckwheat, broomcorn millet, sweet potato, potato, cotton, sesame, peanut, sunflower, radish, carrot, eggplant, leek, green onion, onion, leek, spinach, celery, amaranth, lettuce, crown daisy, daylily, grape, strawberry, sugarcane, tobacco, Brassica vegetables, cucurbit plants, leguminous plants, tea, cassava, and Chinese herbal medicine plants; Preferably, the Chinese herbal medicine plants are selected from Codonopsis pilosula, Eucommia ulmoides, Scutellaria baicalensis, Cannabis sativa, Isatis indigotica, Astragalus membranaceus, Lonicera japonica, Forsythia suspensa, Phellodendron amurense, Coptis chinensis, Polygonum cuspidatum, Gardenia jasminoides, Paris polyphylla, Bupleurum chinense, Isatis indigotica, Taraxacum mongolicum, Lycium chinense, Anemarrhena asphodeloides, Rehmannia glutinosa, Scrophularia ningpoensis, Sterculia lychnophora, Sargentodoxa cuneata, Paeonia veitchii, Pulsatilla chinensis, and Paeonia suffruticosa. Preferably, the Pseudomonas viciae or the bacterial agent is used in controlling plant gray mold disease caused by fungi.

5. The application according to claim 3, wherein The use includes the following application methods: The Pseudomonas viciae secretes siderophores.

6. Use of the Pseudomonas viciae according to claim 1 or the microbial agent according to claim 2 in promoting plant growth, characterized in that, The plants are selected from tomato, pepper, wheat, rice, barley, oats, corn, sorghum, millet, buckwheat, broomcorn millet, sweet potato, potato, cotton, sesame, peanut, sunflower, radish, carrot, eggplant, leek, green onion, onion, leek, spinach, celery, amaranth, lettuce, crown daisy, daylily, grape, strawberry, sugarcane, tobacco, Brassica vegetables, cucurbit plants, leguminous plants, tea, cassava, and Chinese herbal medicine plants; Preferably, the Chinese herbal medicine plants are selected from Codonopsis pilosula, Eucommia ulmoides, Scutellaria baicalensis, Cannabis sativa, Isatis indigotica, Astragalus membranaceus, Lonicera japonica, Forsythia suspensa, Phellodendron amurense, Coptis chinensis, Polygonum cuspidatum, Gardenia jasminoides, Paris polyphylla, Bupleurum chinense, Isatis indigotica, Taraxacum mongolicum, Lycium chinense, Anemarrhena asphodeloides, Rehmannia glutinosa, Scrophularia ningpoensis, Sterculia lychnophora, Sargentodoxa cuneata, Paeonia veitchii, Pulsatilla chinensis, and Paeonia suffruticosa.

7. The application according to claim 6, wherein The use includes the following application methods: (1) The Pseudomonas viciae secretes IAA; (2) The Pseudomonas viciae secretes siderophores; (3) The Pseudomonas viciae dissolves inorganic phosphorus; (4) The Pseudomonas viciae dissolves organic phosphorus; (5) The Pseudomonas viciae secretes protease.

8. The application according to claim 7, characterized in that, The use includes at least one of the following application methods: (1) Used as a root drench; (2) Used as a seed soaking agent; (3) Used as a foliar spraying agent; Preferably, the promotion of plant growth includes at least one of the following applications: (1) Increasing the fresh weight of plants; (2) Increasing the dry weight of plants; (3) Increasing the plant height of plants; Preferably, the use concentration of the Pseudomonas viciae is 1×10 5 -1×10 8 CFU / mL.

9. The application according to claim 8, characterized in that, At least one of a surfactant, a binder, a stabilizer, a pH regulator, a protective agent, an excipient, a disintegrant, a lubricant, a fragrance, a preservative, a suspending agent, a dispersing agent, and a diluent is further added to the root irrigation agent, the seed soaking agent, or the foliar spraying agent.

10. A method for promoting plant growth, characterized in that, It includes the following steps: applying the Pseudomonas viciae described in claim 1 or the bacterial agent described in claim 2 to plants; Preferably, the Pseudomonas viciae is used for root irrigation, seed soaking of the plants, or spraying on the leaves, stems or fruits of the plants.

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