Pseudomonas antagonizing pathogenic bacteria and high auxin production and application thereof

Abstract

This invention discloses a Pseudomonas bacterium that antagonizes pathogens and produces high levels of auxin, and its applications. It relates to the field of microbial technology. The key technical points are: the Pseudomonas bacterium is named *Pseudomonas rhizosphereus* strain FP2034, deposited at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 27742; the 16S rRNA gene sequence of strain FP2034 is shown in Seq ID No. 1. The Pseudomonas bacterium FP2034 provided by this invention exhibits significant inhibitory effects against plant pathogenic bacteria such as *Ralstonia solanaceae*, *Bacterium oxysporum* (tomato bacterial canker), *Bacterium thuringiensis* (rice bacterial leaf blight), *Bacterium streakum* (rice bacterial leaf streak), and *Bacterium thuringiensis* (cruciferous black rot). Pseudomonas bacterium FP2034 possesses functions such as phosphorus solubilization, siderophoresis, NH3, and IAA release, effectively improving the soil nutrient environment and promoting plant growth.

Description

Technical Field

[0001] This invention relates to the field of microbial technology, and more specifically, to a Pseudomonas bacterium that antagonizes pathogens and produces a high amount of growth factor, and its applications. Background Technology

[0002] Crop diseases caused by plant pathogens have severely impacted food crop production in my country and globally. For a long time, the control of crop diseases and the improvement of yields have relied almost entirely on the application of chemical pesticides and fertilizers, which have posed a serious threat to agricultural ecosystems since their introduction. Problems such as increased resistance of pathogenic microorganisms, pesticide residues, changes in soil physicochemical properties, and damage to soil structure urgently require the exploration of environmentally friendly, efficient, and safe production methods and green prevention and control strategies.

[0003] Developing disease-preventing and growth-promoting agents using beneficial microbial resources is one of the important ways to implement a green pest control strategy. Microbial resources are increasingly valued for their wide distribution, abundant resources, diverse species and functions. Actively exploring and utilizing beneficial microbial resources and increasing the development and application of microbial agents will provide sufficient guarantees for the efficient and healthy development of agriculture. Pseudomonas bacteria are widely distributed in the plant rhizosphere environment, possess strong rhizosphere colonization ability, and can promote plant growth and inhibit the proliferation of plant pathogens through functional characteristics such as phosphorus solubilization, nitrogen fixation, iron production, and the secretion of various plant hormones and secondary metabolites. They show great application potential in plant disease control and soil improvement.

[0004] Therefore, screening and identifying new disease-preventing and growth-promoting Pseudomonas bacteria can provide an important resource base for the research and development of multifunctional microbial fertilizers and provide important references for the green prevention and control of plant diseases and the improvement of soil and arable land quality. Summary of the Invention

[0005] The purpose of this invention is to provide a Pseudomonas bacterium that antagonizes pathogens and produces a high amount of auxin, and its applications. This can provide an important resource base for the research and development of multifunctional microbial fertilizers and provide an important reference for the green prevention and control of plant diseases and the improvement of soil and arable land quality.

[0006] The above-mentioned technical objective of the present invention is achieved through the following technical solution: a Pseudomonas bacterium that antagonizes pathogens and produces a high amount of auxin, the Pseudomonas bacterium being named Pseudomonas rhizosphereus FP2034 strain, which is deposited at the China General Microbiological Culture Collection Center with accession number CGMCC No. 27742;

[0007] The 16S rRNA gene sequence of the *Pseudomonas rhizosphereus* strain FP2034 is shown in Seq ID No. 1.

[0008] The present invention also provides a metabolite of a Pseudomonas aeruginosa that antagonizes pathogens and produces a high amount of auxin: the metabolite is a substance secreted into the culture medium by the Pseudomonas rhizosphereus strain FP2034 of maize;

[0009] The method for preparing the metabolite is as follows:

[0010] The *Pseudomonas rhizosphereus* strain FP2034 was activated on KB solid medium. Fresh single colonies were picked and inoculated into KB liquid medium and cultured overnight at 28°C and 200 rpm. Then, the culture was transferred to LB liquid medium at a ratio of 1:1000 and cultured for 48 hours under the same conditions to obtain the fermentation broth, which is the metabolite of the *Pseudomonas rhizosphereus* strain FP2034.

[0011] This invention also provides an application of a Pseudomonas aeruginosa that antagonizes pathogens and produces high levels of auxin: the Pseudomonas rhizosphereus FP2034 of maize or / and the metabolites of Pseudomonas rhizosphereus FP2034 of maize are used to inhibit plant pathogenic bacteria such as Ralstonia solanaceae, bacterial canker of tomato, bacterial blight of rice, bacterial leaf streak of rice, black rot of cruciferous plants, and acidophilus of watermelon.

[0012] The present invention also provides an application of a Pseudomonas aeruginosa that antagonizes pathogens and produces a high amount of auxin: the application of Pseudomonas rhizosphereus FP2034 or / and the metabolites of Pseudomonas rhizosphereus FP2034 in the hydrolysis of organic and inorganic phosphorus.

[0013] The present invention also provides an application of a Pseudomonas rhizosphereus that antagonizes pathogens and produces high levels of auxin: the application of the Pseudomonas rhizosphereus FP2034 or / and the metabolites of Pseudomonas rhizosphereus FP2034 in ammonia production and siderophore production.

[0014] The present invention also provides an application of a Pseudomonas aeruginosa that antagonizes pathogens and produces high levels of auxin: the application of the metabolites of Pseudomonas rhizosphereus FP2034 and / or Pseudomonas rhizosphereus FP2034 in promoting the secretion of plant auxins.

[0015] The present invention also provides an application of a Pseudomonas rhizosphere bacterium that antagonizes pathogens and produces high levels of auxin: the application of Pseudomonas rhizosphereus FP2034 or / and the metabolites of Pseudomonas rhizosphereus FP2034 in promoting lateral root formation and increasing plant biomass.

[0016] In summary, the present invention has the following beneficial effects:

[0017] In this invention, the *Pseudomonas rhizosphereus* FP2034 provided by this invention is a stable, highly efficient, and broad-spectrum plant disease-preventing and growth-promoting bacterium that exhibits significant inhibitory effects on plant pathogenic bacteria such as *Ralstonia solanaceae*, *Bacillus cankerii* of tomato, *Bacillus oryzae* of rice, *Bacillus streak* of rice, and *Bacillus thuringiensis* of cruciferous plants. *Pseudomonas rhizosphereus* FP2034 possesses functions such as phosphorus solubilization, siderophoresis, NH3, and IAA, effectively improving the soil nutrient environment and promoting plant growth. Furthermore, *Pseudomonas rhizosphereus* FP2034 is an easily cultured and preserved, highly efficient, safe, and environmentally friendly plant rhizosphere probiotic that can be used for soil environment improvement, biological control, and plant growth promotion, showing promising development and application prospects as a novel microbial resource. Attached Figure Description

[0018] Figure 1 This is the phylogenetic tree of Pseudomonas beijingensis FP203416S rRNA in Example 2 of the present invention;

[0019] Figure 2 This is a phylogenetic tree of Pseudomonas beijingensis FP2034 from the rhizosphere of maize in Example 2 of the present invention, based on multiple gene loci.

[0020] Figure 3 This invention relates to the determination of the antagonistic bacterial activity of *Pseudomonas beijingensis* FP2034 in the rhizosphere of maize in Example 3 of this invention; (wherein: A, bacterial canker of tomato; B, bacterial blight of rice; C, bacterial leaf streak of rice; D, black rot of cruciferous plants; E, acidophilus of watermelon; F, *Ralstonia solanaceae*).

[0021] Figure 4 This is the IAA production detection result of Pseudomonas beijingensis FP2034 in the rhizosphere of maize in Example 4 of the present invention; (A: The leftmost item in the top row is Salkowski colorimetric solution, the middle item in the top row is the plant growth hormone (IAA) standard sample, the rightmost item in the top row is the negative control of the culture medium, and the three items in the bottom row are three replicates of P. beijingensis FP2034 culture medium; B: Quantitative detection of IAA production by the strain);

[0022] Figure 5This is the result of NH3 production detection by Pseudomonas beijingensis FP2034 in the rhizosphere of maize in Example 5 of the present invention; (wherein, the leftmost one in the top row is the negative control, the middle one in the top row is the positive control, the rightmost one in the top row is Nessler's reagent, and the three in the bottom row are three replicates of P. beijingensis FP2034 culture medium);

[0023] Figure 6 This is the result of the detection of ferrophile production by Pseudomonas beijingensis FP2034 in the rhizosphere of maize in Example 6 of the present invention;

[0024] Figure 7 This is the phosphorus solubilization detection result of Pseudomonas beijingensis FP2034 in the rhizosphere of maize in Example 7 of the present invention; (wherein, A is the hydrolyzed organic phosphorus plate and B is the hydrolyzed inorganic phosphorus plate). Detailed Implementation

[0025] It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of this invention can be combined with each other. Furthermore, unless otherwise specified, the experimental methods in the following embodiments are conventional methods. Unless otherwise specified, the materials and reagents used in the following embodiments are commercially available. The pathogens used in the following embodiments can be collected from the field or obtained from the Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, to replicate the experiments of this application.

[0026] Explanation of cited bacterial strains:

[0027] 1) Clavibacillus termichiganense subsp. miichiganse, which causes bacterial canker in tomatoes, is hereinafter referred to as the tomato bacterial canker pathogen.

[0028] 2) Xanthomonas oryzae epv. oryzae PXO99, which causes bacterial blight in rice, is referred to as the rice bacterial blight pathogen.

[0029] 3) Xanthomonas oryzaepv. oryzicola RS105, which causes bacterial leaf streak in rice, is referred to as rice leaf streak pathogen.

[0030] 4) Xanthomonas campestris pv. carnpestris, which causes black rot in cruciferous vegetables, is hereinafter referred to as the cruciferous black rot fungus.

[0031] 5) Acidovorax citrulli, which causes bacterial fruit spot disease in cucurbits, hereinafter referred to as Acidovorax citrulli.

[0032] 6) Rastonia solanacearum, which causes bacterial wilt in tomatoes, hereinafter referred to as Rastonia solanacearum.

[0033] The following is in conjunction with the appendix Figure 1-7 The present invention will be described in further detail below.

[0034] The strain FP2034 involved in this invention was isolated from the rhizosphere of maize. A phylogenetic tree was constructed using 16S rRNA and multi-site sequences based on gyrB, rpoB, and rpoD; ANI and DDH were calculated; carbon source utilization experiments of strain FP2034 were conducted using the API 20NE and Biolog systems; and fatty acid determination confirmed that this strain is a new species of the genus *Pseudomonas*, taxonomically named *Pseudomonas beijingensis*. This strain was found to possess phosphate solubilization, IAA production, NH3 production, and ferroptophilic activity; and it also showed significant inhibitory effects on plant pathogens such as *Rhizoctonia solani* (bacterial leaf streak of rice) and *Rhizoctonia solani* (soybean vine).

[0035] Example 1

[0036] A type of Pseudomonas that antagonizes pathogens and produces a high amount of growth factor, such as Figure 1 , Figure 2 As shown, Pseudomonas FP2034 is specifically Pseudomonas beijingensis FP2034, which was isolated from the rhizosphere of maize. The Pseudomonas strain was named P. beijingensis FP2034 and is deposited at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 27742. The depositary address is No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing (Institute of Microbiology, Chinese Academy of Sciences), postal code 100101.

[0037] P. beijingensis FP2034 is an aerobic Gram-negative bacterium that fluoresces on King's B medium and grows well at 28-32°C and pH 6-9.

[0038] The 16S rRNA gene sequence of *Pseudomonas rhizosphereus* strain FP2034 is shown in Seq ID No. 1.

[0039] Seq ID No.1:

[0040]

[0041] In this embodiment, a metabolite of a Pseudomonas aeruginosa that antagonizes pathogens and produces a high amount of auxin is also provided: the metabolite is a substance secreted into the culture medium by the Pseudomonas rhizosphereus strain FP2034 of maize.

[0042] The preparation method of the metabolite is as follows:

[0043] The *Pseudomonas rhizosphereus* strain FP2034 was activated on KB solid medium. Fresh single colonies were picked and inoculated into KB liquid medium and cultured overnight at 28°C and 200 rpm. Then, the culture was transferred to LB liquid medium at a ratio of 1:1000 and cultured for 48 hours under the same conditions to obtain the fermentation broth, which is the metabolite of *Pseudomonas rhizosphereus* strain FP2034.

[0044] In this embodiment, an application of a Pseudomonas aeruginosa that antagonizes pathogens and produces high levels of auxin is also provided. Pseudomonas rhizosphereus FP2034 or / and metabolites of Pseudomonas rhizosphereus FP2034 are used to inhibit plant pathogenic bacteria such as Ralstonia solanaceae, bacterial canker of tomato, bacterial blight of rice, bacterial leaf streak of rice, black rot of cruciferous plants, and acidophilus of watermelon.

[0045] In this embodiment, the application of a Pseudomonas aeruginosa that antagonizes pathogens and produces high levels of auxin is also provided, as well as the application of Pseudomonas rhizosphereus FP2034 or / and the metabolites of Pseudomonas rhizosphereus FP2034 in the hydrolysis of organic and inorganic phosphorus.

[0046] In this embodiment, the application of a Pseudomonas aeruginosa that antagonizes pathogens and produces high levels of auxin is also provided, as well as the application of Pseudomonas rhizosphereus FP2034 or / and the metabolites of Pseudomonas rhizosphereus FP2034 in ammonia production and siderophore production.

[0047] In this embodiment, the application of a Pseudomonas aeruginosa that antagonizes pathogens and produces high levels of auxin is also provided, along with the application of Pseudomonas rhizosphereus FP2034 or / and the metabolites of Pseudomonas rhizosphereus FP2034 in promoting the secretion of plant auxins.

[0048] In this embodiment, the application of a Pseudomonas aeruginosa that antagonizes pathogens and produces high levels of auxin is also provided, and the application of Pseudomonas rhizosphereus FP2034 or / and metabolites of Pseudomonas rhizosphereus FP2034 in promoting lateral root formation and increasing plant biomass is also provided.

[0049] The following is the method for preparing the culture medium used in the examples:

[0050] King's B(KB) Liquid Culture Medium: 20g peptone No. 3, 0.4g MgSO4·7H2O, 10mL glycerol, 1.5g K2HPO4, distilled water to a final volume of 1000mL, pH 7.0-7.2 (18g agar added to solid culture medium).

[0051] Luria-Bertani (LB) liquid medium: 5g yeast extract, 10g tryptone, 10g NaCl, distilled water to a final volume of 1000mL, pH 7.0-7.2 (for solid medium, add 18g agar).

[0052] Nutrient Broth (NB) liquid medium: 3g beef extract, 5g peptone, 2.5g glucose, distilled water to a final volume of 1000mL, pH 7.0 (solid medium with 18g agar).

[0053] Trypticase SoyAgar (TSA) medium: 15g casein trypsin digest, 5g soybean flour papain digest, 5g sodium chloride, 15g agar, distilled water to a final volume of 1000mL, pH 7.0-7.5.

[0054] Peptone amination medium: 5g peptone, 0.5g K2HPO4, 0.25g NaCl, 0.5g MgSO4·7H2O, 0.01g FeSO4, and distilled water to a final volume of 1000mL.

[0055] Monkina Organic Phosphorus Medium: Glucose 10g, (NH4)2SO4 0.5g, NaCl 0.3g, KCl 0.3g, FeSO4·7H2O 0.03g, MnSO4·4H2O 0.03g, Egg Yolk Lecithin 0.2g, CaCO3 5g, Yeast Extract 0.4g, Agar 15g, pH 7.0, Distilled Water to a final volume of 1000mL.

[0056] Inorganic phosphorus medium: 10g glucose, 0.5g (NH4)2SO4, 0.2g NaCl, 0.2g KCl, 5.0g Ca3(PO4)2, 0.03g MgSO4·7H2O, 0.03g MnSO4, 0.003g FeSO4, 0.5g yeast extract, 1.2% agar, pH 6.8-7.0, and distilled water to a final volume of 1000mL.

[0057] Preparation of CAS blue qualitative detection plate:

[0058] Solution a—Dissolve 0.012g of CAS in 10mL of deionized water and mix it with 2mL of 1mmol / L FeCl3 solution.

[0059] Solution b—Dissolve 0.015g of HDTMA in 8mL of deionized water.

[0060] Dye solution c—Slowly add solution a to solution b and mix thoroughly.

[0061] Culture medium d—Add 10 mL of 0.1 mol / L phosphate solution (2.427 g Na2HPO4·12H2O, 0.5905 g NaH2PO4·2H2O, 0.075 g KH2PO4, 0.125 g NaCl, 0.25 g NH4Cl, 100 mL deionized water; dilute 10 times before use) and 6.04 g piperazine diethanolsulfonic acid (pipes) to 150 mL of distilled water, mix well, and adjust the pH to 6.8 with 50% NaOH solution. Finally, add 4 g of agar powder.

[0062] Sterilize the dye solution c, culture medium d, and 1 mmol / L CaCl2, 1 mmol / L MgSO4·7H2O, 20% glucose, and 10% casein amino acids (115℃, 20 minutes).

[0063] Measure out 0.2 mL of 1 mmol / L CaCl2, 4 mL of 1 mmol / L MgSO4·7H2O, 6 mL of 10% casein amino acids, and 2 mL of 20% glucose solution and add them to culture medium d. Then slowly add the staining solution c, shake well, and pour into a plate to obtain a blue ferrophile qualitative detection plate.

[0064] Example 2: Isolation and identification of P. beijingensis FP2034 (CGMCC NO.27742)

[0065] I. Isolation of strain FP2034

[0066] Strain FP2034 was isolated from maize rhizosphere soil in Longsha District, Qiqihar, Heilongjiang Province. 4g of rhizosphere soil sample was weighed and added to an Erlenmeyer flask containing 36mL of sterile distilled water. The mixture was shaken for 1 hour at 28℃ and 200rpm. After standing at room temperature for 5 minutes, 1mL of the supernatant was taken and serially diluted 10-fold to 10⁻⁶. -5 100 μL of each concentration was spread onto KB medium plates, with three replicates for each concentration gradient, and incubated at 28°C for 48 h. Single colonies with different morphologies and fluorescence were picked and streaked again for purification to obtain strain FP2034.

[0067] II. Identification of strain FP2034

[0068] The strain FP2034 isolated above was identified by morphological observation, physiological and biochemical characteristics analysis, and genetic evolution analysis, as follows:

[0069] Colony morphology (size, texture, edge) was observed according to the methods in the *Handbook of Systematic Identification of Common Bacteria*, followed by Gram staining and physiological and biochemical characterization. The results showed that strain FP2034 was Gram-negative and rod-shaped. Colonies were milky white, smooth, and regularly round; they produced significant fluorescence on KB medium. Strain FP2034 could grow within a pH range of 6-9 and a temperature range of 4-40℃, with optimal growth conditions of pH 7 and 28-32℃.

[0070] Whole-genome sequencing of strain FP2034 was commissioned to Genewiz Biotechnology Co., Ltd. The sequencing revealed that the full-length genome of strain FP2034 is 6,531,494 bp, with a G+C content of 60.94%. The 16S rRNA gene sequence shown in Sequence Listing 1 was also obtained. Based on this sequence, alignment analysis was performed using EzBioCloud, and a phylogenetic tree was constructed using MEGA software (e.g., ...). Figure 1 (As shown). To identify closely related bacteria, phylogenetic analysis was performed based on multiple conserved sites (gyrB, rpoB, and rpoD genes) (e.g. Figure 2 (As shown). Strain FP2034 was found to be related to *Pseudomonas brassicacearum* LMG 21623. T ) and Pseudomonas kilonensis (DSM 13647) T The closest kinship is that of the two species.

[0071] Furthermore, the average nucleotide identity (ANI) was calculated using FastANI software, and the DNA-DNA hybridization value (DDH) was calculated using an online analysis website. The results are shown in Table 1 below. *Pseudomonas thivervalensis* FP2034 and *P. thivervalensis* DSM 13194 T The ANI value was the highest, at 93.1, which is below the threshold of 95; the DDH value between the two was only 49.8%, far less than the same threshold of 70%. This further confirms that Pseudomonas FP2034 is a new species.

[0072] Table 1. Analysis of ANI and DDH values ​​of Pseudomonas FP2034 and its closely related type strains.

[0073]

[0074]

[0075] Based on phylogenetic analysis and ANI and DDH calculations, the differences in physiological and biochemical indicators between *Pseudomonas thivervalensis* FP2034 and its closely related model strains were analyzed. The physiological and biochemical activities of the three strains were analyzed using the API 20NE and BIOLOG systems, and the results are shown in Table 2 below. The results showed that strain FP2034 and its closely related model strains could utilize N-acetylglucosamine, but could not utilize D-mannose, D-sorbitol, or L-histidine. Strain FP2034 could utilize D-fucose, D-fructose-6-PO4, D-aspartic acid, L-glutamic acid, galacturonic acid, glucuronic acid, and HCl guanidine hydrochloride; but could not utilize L-arginine, gelatin, sucrose, α-D-glucose, D-serine, or D-gluconic acid. In contrast, the closely related model strain *P. thivervalensis* DSM13194... T It can utilize gelatin, α-D-glucose, and D-serine, but cannot utilize D-aspartic acid or galacturonic acid. The closely related type strain is *P. kilonensis* DSM 13647. T It can utilize sucrose, α-D-glucose, and β-glucuronic acid, but cannot utilize D-fucose, D-aspartic acid, galacturonic acid, or glucuronic acid. The closely related type strain is *P. brassicacearum* JCM 11938. T Gelatin, α-D-glucose, D-serine, etc. can be used, but galacturonic acid and glucuronic acid cannot be used.

[0076] Table 2. Physiological and biochemical characteristics of Pseudomonas FP2034 and closely related type strains.

[0077]

[0078]

[0079] Note: "+" indicates that the carbon and nitrogen source can be used for growth, "-" indicates that it cannot be used, "w" indicates that growth is weak on the basis of the carbon and nitrogen source, and "nd" indicates that there is no data.

[0080] Fresh colonies were picked and cultured on TSA plates at 28℃ for 1 day for fatty acid composition determination. The methyl ester content of fatty acids in the cells was analyzed using the Sherlock 6.2 Microbial Identification System (MIDI) and the TSBA6 database (as shown in Table 3 below). The results showed that the main fatty acid components of strain FP2034 were basically the same as those of its closely related model bacteria, but there were significant differences in their content.

[0081] Table 3. Cellular fatty acid composition and content of strain FP2034 and its closely related type strains

[0082]

[0083]

[0084] In summary, based on the morphological characteristics, culture properties, and phylogenetic analysis of strain FP2034, it can be clearly identified as *Pseudomonas* sp. The ANI and DDH values ​​of strain FP2034 and its closely related type bacteria are both below the critical values ​​for species classification, and there are significant differences in physiological and biochemical indicators and fatty acid content. Therefore, strain FP2034 is determined to be a new species of the genus *Pseudomonas*, and it is named *Pseudomonas beijingensis*. *Pseudomonas beijingensis* FP2034 was deposited at the China General Microbiological Culture Collection Center (CGMCC) in June 2023. Its registration number at CGMCC is CGMCC NO. 27742. It will be referred to as *P. beijingensis* FP2034.

[0085] Example 3: Determination of the antibacterial spectrum of P. beijingensis FP2034

[0086] The tested plant pathogens were: bacterial canker of tomato, bacterial blight of rice, bacterial leaf streak of rice, black rot of cruciferous plants, acidophilus of watermelon, and Rilke of solanaceous plants.

[0087] Antagonistic experiments against the aforementioned plant pathogens were conducted using a plate confrontation culture method. The confrontation experiment method was as follows: Fresh *P. beijingensis* FP2034 and the pathogenic bacteria were inoculated into LB and NB media, respectively, and incubated overnight at 28°C and 200 rpm. The 1% agar NA medium was melted by heating and then cooled to approximately 45°C in a water bath. The concentration of the freshly cultured pathogenic bacteria in the NB medium was adjusted to 1×10⁻⁶. 8 CFU / mL (OD) 600 =0.1), add 1% to NA medium at 45℃, mix thoroughly, and pour into plates. Inoculate 10 μL of *P. beijingensis* FP2034 culture medium onto the plates, with plates inoculated only with the pathogen serving as controls. After air drying, incubate upside down in a 28℃ incubator, with each treatment repeated three times. Observe and measure the diameter of the inhibition zone after 48 hours of incubation.

[0088] The results showed that *P. beijingensis* FP2034 had good inhibitory effects on *Bacterium chrysogenum* of tomato, *Bacterium thuringiensis* of rice, *Bacterium streak* of rice, *Bacterium tumefaciens* of cruciferous plants, *Acidophilus citrinum* of watermelon, and *Ralstonia solanaceae*. Figure 3 (As shown). This indicates that P. beijingensis FP2034 has broad-spectrum and highly effective antibacterial activity, and has potential application value in the control of various plant diseases.

[0089] Example 4: IAA production capacity test of P. beijingensis FP2034

[0090] LB medium contained tryptophan at a final concentration of 3 mM. Fresh bacterial cells were inoculated into the medium and cultured at 28°C and 200 rpm for 4 days. The negative control was a culture medium inoculated with bacteria that did not produce IAA, and the positive control was 100 mg / L IAA. Salkowski colorimetric solution: 50 mL 35% HClO4 and 1 mL 0.5 mol / L FeCl3.

[0091] Qualitative detection: Mix 100 μL of culture medium with an equal volume of Salkowski colorimetric solution and add to a transparent plastic blood coagulation plate. Incubate at room temperature in the dark for 30 minutes, then observe. A red color indicates the presence of IAA (e.g., Figure 4 (As shown in A in the figure). The results showed that P. beijingensis FP2034 can secrete IAA.

[0092] Quantitative detection: Centrifuge the culture medium at 10,000 rpm for 10 min, take the supernatant and mix it with an equal volume of Salkowski colorimetric solution, then let it stand at room temperature in the dark for 30 min, and measure its OD. 530 Value, and measure the OD of the culture medium. 600 The value was compared with the standard curve to calculate the amount of IAA secreted by this strain. P. beijingensis FP2034 secreted 52.29 mg / L of IAA. Figure 4 (As shown in B in the figure).

[0093] Example 5: P. beijingensis FP2034 has the ability to produce ammonia.

[0094] Freshly cultured *P. beijingensis* FP2034 was transferred to peptone-ammoniated medium and incubated at 28°C and 200 rpm for 48 h. 200 μL of culture was dropped onto a transparent plastic hemagglutination plate; the control was uninoculated peptone-ammoniated medium. Three drops of Nessler's reagent were added to both the culture medium and the peptone-ammoniated medium. The appearance of a yellow or brownish-red precipitate indicated that the strain possessed the ability to produce NH3. The results showed that a distinct brownish-red precipitate appeared in the culture medium of *P. beijingensis* FP2034 after the addition of Nessler's reagent (e.g., ...). Figure 5 As shown in the figure, this indicates that P. beijingensis FP2034 has a significant ammonia production capacity.

[0095] Example 6: P. beijingensis FP2034 has the ability to produce ferropterins.

[0096] Activated *P. beijingensis* FP2034 was inoculated into LB broth and incubated overnight at 28°C and 200 rpm with shaking. 2 μL of the culture was spotted onto a heptaphilic assay plate, repeated three times. After 3 days of incubation at 28°C, the presence of a yellow halo around the colony was observed. Because heptaphilic cells compete with EDTA for iron ions in the medium, the blue color in the medium fades, resulting in a faded halo around the colony. The results indicate that a distinct faded halo appears around *P. beijingensis* FP2034 colonies, demonstrating that this strain possesses the ability to produce heptaphilic cells (e.g., yellow halo). Figure 6 (As shown).

[0097] Example 7: P. beijingensis FP2034 can hydrolyze organic and inorganic phosphorus.

[0098] Activated *P. beijingensis* FP2034 was inoculated into LB broth and incubated overnight at 28°C and 200 rpm with shaking. 2 μL of the culture was then spot-inoculated onto both organic and inorganic phosphate agar plates, repeated three times. After drying, the plates were incubated upside down at 28°C for 5-7 days, observing for the appearance of hydrolysis halos. Results showed no changes in the control group plates, while clear hydrolysis halos (as shown in the image) appeared around the colonies on the organic and inorganic phosphate agar plates inoculated with *P. beijingensis* FP2034 culture. Figure 7 As shown in the figure, this indicates that P. beijingensis FP2034 can hydrolyze organic and inorganic phosphorus and can be used for soil improvement.

[0099] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A type of Pseudomonas pekinensis antagonistic to pathogens ( Pseudomonas beijingensis FP2034, characterized in that, It is deposited at the China General Microbiological Culture Collection Center, with accession number CGMCC No. 27742; The Beijing Pseudomonas FP2034 strain 16S rRNA The gene sequence is shown in Seq ID No.

1.

2. The application of *Pseudomonas pingeri* FP2034, an antagonistic pathogen according to claim 1, is characterized in that... The *Pseudomonas pingeri* FP2034 was used to inhibit the plant pathogenic bacterium *Rhespermum jasminoides* (Solanaceae). Rastonia solanacearum Bacterial canker of tomatoes Clavibacter michiganense subsp. michiganse Rice bacterial blight pathogen Xanthomonas oryzae pv. oryzae Bacterial leaf streak of rice Xanthomonas oryzae pv. oryzicola Black rot fungus of the cruciferous family Xanthomonas campestris pv. carnpestris And watermelon acidophilus Acidovorax citrulli .

3. The application of *Pseudomonas pingense* FP2034, an antagonistic pathogen according to claim 1, is characterized in that... The application of Pseudomonas pingeri FP2034 in the hydrolysis of organic and inorganic phosphorus.

4. The application of *Pseudomonas pingeri* FP2034, an antagonistic pathogen according to claim 1, is characterized in that... The application of Pseudomonas pingeri FP2034 in ammonia production and siderophore generation.

5. The application of *Pseudomonas pingeri* FP2034, an antagonistic pathogen according to claim 1, is characterized in that... Application of Pseudomonas pingeri FP2034 in the secretion of plant growth hormones.

Images