CN114836352A

CN114836352A - Plant rhizosphere growth promoting strain F13 and application thereof

Info

Publication number: CN114836352A
Application number: CN202210556631.6A
Authority: CN
Inventors: 梁卫驱; 胡珊; 黄皓; 聂松青; 罗华建; 徐匆; 胡楚维; 黄晓彦; 陈仕丽
Original assignee: DONGGUAN RESEARCH CENTER OF AGRICULTURAL SCIENCE
Current assignee: DONGGUAN RESEARCH CENTER OF AGRICULTURAL SCIENCE
Priority date: 2022-05-19
Filing date: 2022-05-19
Publication date: 2022-08-02
Anticipated expiration: 2042-05-19
Also published as: CN114836352B

Abstract

The invention discloses a plant rhizosphere growth promoting strain F13 and application thereof, wherein the plant rhizosphere growth promoting strain is classified and named as pseudomonas aeruginosa (pseudomonas aeruginosa)Pseudomonas aeruginosa) Has been preserved in the Guangdong province microorganism culture collection center with the preservation number of GDMCC No. 61146 and the preservation date of GDMCC No. 61146The collection address is as follows at 14 days 8/2020: no. 59 large yard, No. 5, of Jifurao Zhongluo, Guangzhou, Guangdong, China. The plant rhizosphere growth promoting strain F13 obtained by screening can efficiently dissolve phosphorus and potassium, and is widely applied to being used as a biological organic fertilizer.

Description

Plant rhizosphere growth promoting strain F13 and application thereof

Technical Field

The invention relates to the technical field of microorganisms, in particular to a plant rhizosphere growth promoting strain and application thereof.

Background

Plant Growth-promoting Rhizobacteria (PGPR) refers to a microorganism that is present in the microenvironment of the soil surrounding the rhizosphere surface and root system of a Plant and can significantly promote the Growth of the Plant in a direct or indirect manner. The PGPR can not only promote the growth of plants, but also prevent and control plant diseases. The action mechanism of the PGPR can be roughly classified into two types of direct action and indirect action, the direct action mechanism is that the PGPR can synthesize some hormones (such as auxin, indoleacetic acid and the like) for promoting the growth of plants, the shapes of some ineffective elements in soil are converted into useful shapes so as to be beneficial to the absorption of the plants (such as nitrogen fixation, phosphorus dissolution, potassium dissolution and the like) to directly act on the plants, and the growth and development of the plants are promoted; the mechanism of indirect action is that PGPR inhibits pathogens or slows down the adverse effects of plant disease on plant growth through metabolic products such as siderophores and antibiotics.

Current research shows that PGPR-based formulations not only protect plants from various pathogens by acting as biocontrol agents, but also have growth-promoting effects as demonstrated by tests on various plants. In economically important crops such as rice, peas, soybeans, wheat, tomatoes, most PGPRs improve plant growth characteristics including plant height, seedling vigor, seed germination, leaf area, fresh and dry weight, and yield and nutrient content. The biological pesticide is more green and effective to replace chemical pesticide, and is the main development direction of future fertilizers. Therefore, PGPR strains with double effects of pesticide and fertilizer and good stability are separated and screened, and the large-scale popularization and application are of great importance to the development of modern agriculture.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a plant rhizosphere growth promoting strain F13 capable of efficiently dissolving phosphorus or potassium.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention adopts a 5-point sampling method to take grape rhizosphere soil in Guangdong Dongguan vineyard, and the soil is weighed and dissolved in sterile water to prepare 10 ^-3 、10 ^-4 、10 ^-5 And 10 ^-6 And respectively and uniformly coating the multiplied suspensions on a phosphorus and potassium dissolving solid culture medium, selecting strains with good effect, further purifying the strains on an LB culture medium, repeating a plate phosphorus and potassium dissolving test on each strain, and screening to obtain the plant rhizosphere growth promoting strain F13 capable of efficiently dissolving phosphorus and potassium.

A plant rhizosphere growth promoting strain is classified and named as Pseudomonas aeruginosa (Pseudomonas aeruginosa), has a strain number of F13, is deposited in Guangdong province microorganism culture collection center, has a collection number of GDMCC No. 61146, has a collection date of 2020, 8 months and 14 days, and has a collection address of: no. 59 large yard, No. 5, of Jifurao Zhongluo, Guangzhou, Guangdong, China.

Compared with the prior art, the invention has the following beneficial effects: the plant rhizosphere growth promoting strain F13 obtained by screening can efficiently dissolve phosphorus and potassium, and is widely applied to being used as a biological organic fertilizer. Meanwhile, the plant rhizosphere growth promoting strain F13 has antagonistic action on plant pathogenic bacteria, has drug sensitivity to antibiotics, can be used as an iron production carrier, can produce shenqinmycin, can be used for field prevention and control of summer black grape powdery mildew or kidney bean powdery mildew, has growth promoting and yield increasing effects on kidney beans, and can be used for preparing a microbial agent for resisting diseases, promoting growth and increasing yield.

Drawings

FIG. 1 is a phosphorus soluble circle diagram of strain F13;

FIG. 2 is a colony morphology of strain F13 on potassium-resolving plates;

FIG. 3 is a colony map on the culture medium of strain F13;

FIG. 4 is a microscopic photograph (10X 100) of a colony of strain F13;

FIG. 5 is a diagram showing the result of electrophoresis of a PCR product of F1316S rDNA; note: m is a DNA marker, 1 and 2 are PCR products;

FIG. 6 is a diagram of F13 phylogenetic dendrogram based on the 16S rDNA sequence;

FIG. 7 is a graph of the antagonistic effect of strain F13;

FIG. 8 is a graph showing the results of the experiment for siderophore production by strain F13;

FIG. 9 is a graph of the yield of PCA in different media for strain F13;

FIG. 10 is a graph showing the control effect of strain F13 on the powdery mildew of summer black grapes;

FIG. 11 is a graph showing the control effect of strain F13 on powdery mildew of kidney beans;

FIG. 12 is a graph showing the effect of strain F13 on the absorption of phosphorus and potassium by green bean plants.

Detailed Description

1. Experimental Material

1.1 culture Medium: organophosphorus bacteria medium (containing agar), silicate medium, CAS detection medium: qingdao high-tech park Haibo Biotechnology Co., Ltd; LB medium, potato agar medium: kyoto Tokay microbial science and technology Co., Ltd; mongina lecithin medium: sucrose (glucose) 10.0g, (NH) ₄ ) ₂ SO ₄ 0.5g，NaCl 0.3g，MgSO ₄ ·7H ₂ O 0.3g，FeSO ₄ ·7H ₂ O 0.03g，NaCl 0.3g，MnSO ₄ ·7H ₂ O 0.03g，CaCO ₃ 5.0g, 1.0g of lecithin (the lecithin is firstly dissolved in 75% ethanol), 1L of deionized water, and the pH value is 7.2-7.4; KB medium: peptone 10g, Glycerol 10mL, K ₂ HPO ₄ 1.5g，MgSO ₄ ·7H ₂ O1.5 g, ionized water 1L, pH 7.0.

1.2 test phytopathogens: provided by the plant pathology line of south China agricultural university. Rhizoctonia solani (Rhizoctonia solani), Colletotrichum capsici (Colletotrichum capsicii), Sciadopitys banana (Fusarium oxysporum f.sp.), Fusarium arachidis hypogaeae (Cercospora arachidicola Hori), maize microsporum maydis (Bipolaris maydis), Saccharum officinarum (Colletotrichum falcatum Went.), Fusarium graminearum (Fusarium graminearum) and Rhizoctonia Benincasae (Fusarium solani).

1.3 Main experimental equipment: electronic balance of main equipment: sidorist scientific instruments (Beijing) Inc.; YXQ-LS-75G vertical pressure steam sterilizing pan: shanghai Bowen Ministry of Industrial science, medical facilities; ZHWY-211B constant temperature culture shaker: shanghai Zhicheng analytical instruments manufacturing, Inc.; SW-CJ-1F clean bench: suzhou Antai air technology, Inc.; an upright fluorescence microscope: olympus, Olympus; LRH-250 biochemical incubator: Shanghai-Hengchang scientific instruments, Inc.; UV-1800 full wavelength scanning spectrophotometer: shimadzu, Japan; TSQ Quantum Ultra & Access MAX liquid chromatography mass spectrometer: sammer Feishale science and technology (China) Co.

1.4 tested species of green beans: jadeite No. 12 cowpea, yucca changii multi-seed limited; the tested grape varieties are as follows: summer black grape

2. Experimental methods

2.1 isolation and screening of plant growth-promoting rhizobacteria F13

Taking grape rhizosphere soil in Guangdong Dongguan vineyard by adopting a 5-point sampling method, uniformly mixing the samples, putting the samples into a sterile self-sealing bag, storing the samples in a refrigerator at 4 ℃, and separating the samples as soon as possible. Under aseptic conditions, 10g of soil is weighed, dissolved in 90mL of sterile water, shaken for 1h on a vibrating screen at 120r/min, and diluted to 10 degrees in a gradient manner ^-3 、10 ^-4 、10 ^-5 And 10 ^-6 Respectively and uniformly coating 100 mu L of each dilution of the suspension on a phosphorus and potassium dissolving solid culture medium, culturing in an incubator at 36 ℃, and observing whether a phosphorus dissolving ring is arranged on a phosphorus dissolving plate and a non-smooth transparent oil is arranged on a potassium dissolving plateStrains of the colony of drops. And selecting the strains with good effect, further purifying the strains on an LB culture medium, and repeating a plate phosphorus and potassium dissolving test on each strain. Finally, each pure culture strain was transferred to a glycerol tube with a final concentration of 30% and stored in a refrigerator at-20 ℃.

2.1.1 determination of phosphorus solubilizing ability of plant growth promoting rhizobacteria F13

A phosphorus ring dissolving method: and (3) inoculating the strain to be detected to an organic phosphorus solid culture medium, repeating for 3 times, culturing for 3 days in a thermostat at 36 ℃, and preliminarily determining the strength of the organic phosphorus dissolving capacity of the strain according to the ratio (D/D) of the diameter (D) of the transparent ring to the diameter (D) of the bacterial colony.

A phosphomolybdenum blue colorimetric method: the selected strain was inoculated into 20mL of LB medium sterilized at high temperature, activated and cultured at 36 ℃ and 130rpm for 18 hours to obtain a seed solution. The seed solution was inoculated into 100mL of a high-temperature sterilized Monkina lecithin medium at an inoculum size of 1.5% (by volume), and the fermentation medium without any inoculum was used as a blank control, and 3 replicates of each treatment were incubated at 36 ℃ and 150rpm for 5 days. And 5d, centrifuging 50mL of fermentation liquor at 4 ℃ and 9000rpm for 15min, taking supernatant, and measuring the effective phosphorus content in the fermentation liquor by using a phosphomolybdic blue colorimetric method, wherein the difference value of the soluble phosphorus contents of the experimental group and the control group is the phosphorus dissolving amount of the strain to be measured. The map of the soluble phosphorus circle of strain F13 is shown in FIG. 1.

Phosphorus dissolution rate (%) — content of available phosphorus in test group (mg/L) -content of available phosphorus in control group (mg/L)/content of available phosphorus in test group (mg/L) × 100.

2.1.2 determination of Potassium-solubilizing ability of plant growth-promoting rhizobacteria F13

The selected strain was inoculated in 20mL of LB at 36 ℃ and activated at 130rpm for 18 hours to prepare a seed solution. The seed solution was inoculated into 100mL of a high-temperature sterilized acid-salt bacterial liquid medium at an inoculum size of 1.5% (by volume), and cultured at 36 ℃ for 5 days in 3 replicates per treatment setup with respect to the fermentation medium without any inoculum size. Centrifuging the fermentation liquid at 4 deg.C and 9000rpm for 15min, collecting supernatant, and measuring the content of quick-acting potassium in the solution by atomic absorption spectrophotometry. And then calculating the potassium-solubilizing rate by using a formula, and measuring the potassium-solubilizing capability of the strain. The colony morphology of the strain F13 on the potassium-solubilizing plate is shown in FIG. 2.

Potassium dissolution rate (%) — content of quick-acting potassium in test group (mg/L) -content of quick-acting potassium in control group (mg/L)/content of quick-acting potassium in test group (mg/L) × 100.

2.2 identification of the Strain

2.2.1 morphological Observation referring to Bergey's Manual of bacteriology (eighth edition), observe the morphology, color, etc. of the growing colony of phosphate solubilizing bacteria on the surface of LB medium; selecting young culture, smearing, gram staining, and observing thallus morphology, size, gram staining reaction, spore existence, morphology and implantation position under microscope.

2.2.2 API System identification the strains were subjected to physiological and biochemical identification using API 20NE and API 20E systems from Meriella, France.

2.2.316S rDNA molecular identification and bacterial genome DNA extraction, PCR amplification was performed using bacterial 16S rDNA universal primers (27F: 5'-AGAGTTTGATCCTGGCTCAG-3', 1492R: 5'-TACGGCTACCTTGTTACGACTT-3'). The PCR product is detected by gel electrophoresis and then sent to Shanghai Meiji biological medicine science and technology Limited company for sequencing. The sequencing results were submitted to GenBank for BLAST alignment, and 16S rDNA gene sequences of sibling species were selected for homology analysis, and MEGA11.0 was used to construct phylogenetic evolutionary trees, as shown in FIG. 6.

2.3 antagonistic action of Strain F13 on plant fungal diseases

Preparing a fermentation liquid of the strain: inoculating single bacterial colony to LB culture medium, performing shaking culture at 36 deg.C and 130r/min for 18h, and adjusting OD of bacterial liquid ₆₀₀ To 1.0 as seed liquid. Transferring the seed solution to LB culture medium according to 1.5% (volume ratio), and performing shaking culture at 28 deg.C and 150r/min for 6d to obtain fermentation liquid.

The fermentation liquor bacteriostasis spectrum determination adopts a plate confronting method to determine the antagonistic action of bacteria and pathogenic fungi. Fungi and bacteria were inoculated simultaneously onto PDA plates, the center of the plate was inoculated with a fungus cake of 6mm in diameter, the center was inoculated with F13 fermentation broth (20. mu.L of the broth was dropped vertically onto the medium with a pipette) at three points equidistant from the center by 2cm, and 3 replicates of each combination were used as controls on fungal plates not inoculated with bacteria. And (4) culturing at 28 ℃, observing the growth condition, measuring the radius of the fungi from the far end and the near end of the bacteria when the control colony grows full of the plate, and calculating the inhibition rate of the bacteria on the pathogenic fungi. The higher the inhibition rate, the stronger the inhibition of the fungus by the bacteria.

The hypha growth inhibition ratio (%) (control average colony diameter (mm) — treatment average colony diameter (mm) — control average colony diameter (mm) × 100%).

2.4 Strain F13 drug sensitivity test

The K-B paper diffusion method is adopted to carry out drug sensitivity experiment on the strain F13. The screened bacteria are inoculated into 20mL LB culture medium sterilized at high temperature, activated and cultured for 24h at 36 ℃ and 130r/min, and evenly spread on beef extract peptone agar culture medium. Uniformly distributing and sticking the drug sensitive paper sheets soaked with various antibiotic solutions on a culture medium, culturing at 36 ℃ for 24h, and measuring the diameter of a bacteriostatic circle. The sensitivity of the strain to the drug was judged according to the criteria provided by NCCLS.

2.5 detection of Ferrophilic Activity of Strain F13

The strain is spotted on a CAS detection medium plate, the plate is cultured for 7d at 36 ℃, whether obvious orange or dark yellow siderophore halos appear around colonies is observed, and if the halos appear, the bacteria can secrete siderophore.

2.6 quantitative analysis and identification of shenqinmycin produced by strain F13

The shenqinmycin is also called phenazine-1-carboxylic acid (PCA) which is an important antagonistic secondary metabolite of pseudomonas and has double functions of broad-spectrum inhibition of plant pathogenic bacteria and promotion of plant growth.

The fermentation conditions of the strains are as follows: a single bacterial colony is selected from an LB plate and inoculated into 20mL of LB liquid culture medium at 36 ℃, the shaking culture is carried out for 18h at 130r/min, and the OD600 of bacterial liquid is adjusted to 1.0 to be used as seed liquid. The seed solution was inoculated into KB medium and soybean extract medium at 1.5% inoculum size, respectively, and cultured in constant temperature shaker at 36 and 28 deg.C and 130rpm for 120 h. The fermentation broth was centrifuged at 9000rpm for 15min at 4 ℃ to obtain the supernatant.

Detecting shenqinmycin: diluting the supernatant with methanol, centrifuging, collecting supernatant, filtering with filter membrane, and analyzing by sample injection. Detecting by using a TSQ Quantum Ultra & Access MAX liquid chromatography-mass spectrometer, wherein the analysis parameters are as follows: the mobile phase is 0.1% formic acid water (A) and methanol (B); the flow rate is 0.4 mL/min; the sample injection amount is 10 mu L; the chromatographic column is Hypersil-Gold-C18 (100X 2.1mm, 5 μm); gradient elution procedure is 0-2min, 95% A; 2min-6min, 95% -2% A; 6min-8min, 2% A; 8.1-10 min, 2-95% A. And dissolving the shenqinmycin standard substance by using methanol to prepare a standard solution, and drawing a standard curve.

2.7 preliminary study on field prevention and treatment of grape powdery mildew and kidney bean powdery mildew by Strain F13

Powdery mildew is a common plant disease, is infected and attacked by fungi, is a disease which is difficult to control in the growth process of crops, can infect leaves of grapes and young shoots and fruits, causes yield reduction of the crops to different degrees due to the occurrence of the powdery mildew, and even causes dead production and no harvest of farmers if the powdery mildew is serious.

2.7.1 preparation of fermentation broth of Strain

Inoculating single bacterial colony to LB culture medium, performing shaking culture at 36 deg.C and 130r/min for 18h, and adjusting OD of bacterial liquid ₆₀₀ To 1.0 as seed liquid. Transferring the seed solution to LB culture medium according to 1.5% (volume ratio), and performing shaking culture at 28 deg.C and 150r/min for 6d to obtain fermentation liquid.

2.7.2 field control effect test medicament and design

The field control effect test is provided with three treatments: treatment 1: f13 diluted fermentation liquor is sprayed on the leaf surface by 50 times; and (3) treatment 2: diluting 75% chlorothalonil wettable powder by 600 times, and spraying on leaf surfaces; and (3) treatment: clear water control

The summer black grape test was performed as follows:

3 cells with powdery mildew outbreaks are selected from a vineyard which is a facility of agricultural science research center in Dongguan city, and each cell corresponds to one test treatment. The test is carried out in 2021, 11, 3 days and the first time, and in 11, 7 days and the second time, the pesticide application is required to be uniform and fine, the spray head faces upwards, the spraying liquid amount is preferably that liquid drops keep a state of dripping on the front and back surfaces of the leaves and not dripping, and the field management is carried out according to the conventional management in each test treatment. The disease condition is investigated in several times, the first investigation is before the pesticide is applied, the second investigation is after the first pesticide is applied for three days, and the third investigation is after the first pesticide is applied for seven days. Randomly surveying 10 new shoots in each district, surveying 5-8 leaves in each shoot, grading each leaf according to the percentage of the lesion area, recording and surveying the total number of leaves and the number of leaves with diseases at each grade, and calculating the disease index and the prevention and treatment effect according to the following formula.

The disease grading standard is divided into 7 grades according to the percentage of the powdery mildew distribution area (disease spots) of the leaves: level 0: the leaves are healthy and have no disease spots; level 1: the area of the lesion is less than 10%; grade 3, the lesion area is 11-20%; the area of the 5-grade lesion spots is 21-30 percent; grade 7, the lesion area is 31 to 50 percent; grade 9, the lesion area is more than 50%.

The green bean test was performed as follows:

3 cowpea powdery mildew disease-causing cells are selected in a simple greenhouse of an agricultural science research center in Dongguan city, and each cell corresponds to one test treatment. The test is carried out in 2021, 11, 29 days for the first time, 12, 1 days for the second time, the pesticide application is required to be uniform and fine, the spray head faces upwards, the spraying liquid amount is preferably that liquid drops keep a state of dripping on the front and back surfaces of the leaves without dripping, and each test treatment is carried out by field management according to conventional management. The disease condition is investigated in several times, the first investigation is before the pesticide is applied, the second investigation is after the first pesticide is applied for 4 days, and the fourth investigation is after the first pesticide is applied for 9 days. Randomly investigating 10 plants in each cell, investigating 5-8 leaves in each cell, grading each leaf according to the percentage of the lesion area, recording and investigating the total number of leaves and the number of leaves with diseases at each level, and calculating the disease index and the prevention and treatment effect according to the following formula.

The disease grading standard is divided into 7 grades according to the percentage of the powdery mildew distribution area (disease spots) of the leaves: level 0: the leaves are healthy and have no disease spots; level 1: the area of the lesion spots is less than 10 percent; grade 3, the lesion area is 11-20%; the area of the 5-grade lesion spots is 21-30 percent; grade 7, the lesion area is 31 to 50 percent; grade 9, the lesion area is more than 50%.

2.8 study of growth-promoting and yield-increasing ability of Strain F13 on beans

Inoculating single bacterial colony to LB culture medium, performing shaking culture at 36 deg.C and 130r/min for 18h, and adjusting OD of bacterial liquid ₆₀₀ To 1.0 as seed liquid. Transferring the seed liquid into LB culture medium according to the inoculum size of 1.5% (volume ratio), and performing shaking culture at 28 deg.C and 150r/min for 6d to obtain fermentation liquid.

And when the kidney bean seedlings grow to 7-8 leaf stages, uniformly irrigating 300mL of the 50-time diluted zymophyte liquid into the kidney bean rhizosphere soil, irrigating 300mL of the 50-time diluted sterilized LB culture medium in contrast, treating 50 kidney beans each, and repeatedly irrigating roots for 1 time after 7 days. After 15 days of treatment, randomly sampling 8 beans for each treatment, measuring the plant height, leaf number and stem thickness of the beans, and calculating the growth promotion and amplification; at harvest, the yield of each treatment was measured.

2.9 study of the Effect of the F13 strain on the absorption of phosphorus and potassium elements in vigna unguiculata plants

The harvested green bean plants are sent to the institute of agricultural resources and environment of agricultural sciences of Guangdong province for determination of phosphorus and potassium, and the detection method refers to LY/T1271-1999.

3. Results of the experiment

3.1 measurement results of phosphorus-solubilizing and potassium-solubilizing abilities of Strain F13

The strain F13 has strong phosphorus-dissolving potassium-dissolving activity, the ratio of phosphorus-dissolving index (D/D) is 4.25 +/-0.20, and the phosphorus-dissolving rate is 82.67%; the potassium-dissolving rate was 75.67%.

3.2 identification of Strain F13

3.2.1 colony culture characteristics: the strain F13 is cultured for 24h at 36 ℃ in nutrient agar, the bacterial colony is light yellow and flat, the surface is smooth, moist and glossy, the edge is irregular, microscopic examination shows gram-negative bacilli, and the thalli are arranged in a single, double or short chain shape.

3.2.2 physiological and Biochemical test results

The results of physiological and biochemical tests of the strain F13 are shown in Table 1, and the strain can utilize lactose, galactose, glycerol, arabinose, fructose, mannitol, inositol, sucrose, rhamnose and the like; maltose, raffinose, and salicin cannot be used. And (5) liquefying the gelatin. The starch has strong hydrolysis. Indole test is negative. Catalase is positive.

TABLE 1 physiological and biochemical identification results of Strain F13

Physiological and biochemical test	The result of the detection	Physiological and biochemical test	The result of the detection	Physiological and biochemical test	The result of the detection
						Citric acid salt	+	Indole test	—	Methyl Red	+
Contact enzyme	+	Starch waterSolution (II)	+	Liquefaction of gelatin	+
						Lactose	+	Fructose	+	Xylose	+
Mannitol	+	Glycerol	+	Arabinose	+
						Sucrose	+	Inositol	+	Rhamnose	+
Galactose	+	Arabinogalactan	+	Maltose	—
						Salicylate glycoside	—	Raffinose	—

Note that "+" is positive reaction or can be grown and utilized; "-" indicates that the reaction is negative or cannot be grown and utilized.

3.2.3 molecular identification results

The genomic DNA of the strain F13 was used as a template, and PCR amplification was carried out using a universal primer for bacterial 16S rDNA gene, to thereby amplify a DNA fragment having a length of about 1.5Kb (FIG. 5). The sequencing results were submitted to the GenBank database for Nucleotide BLAST sequence alignment analysis to find that the homology of the strain F13 with Pseudomonas aeruginosa strain YW1 was 100%. In order to determine the genetic relationship and the systematic status among the strains, a phylogenetic evolutionary tree (figure 6) is constructed by using MEGA11, and the F13 is identified as the pseudomonas aeruginosa by combining the morphological characteristics and the physiological and biochemical test results of the strain F13.

3.3 antagonistic action of Strain F13 on plant fungal diseases

The antagonistic action of the F13 fermentation broth on plant pathogenic fungi is determined by adopting a plate confronting method, the result is shown in FIG. 7, as shown in Table 2, the F13 fermentation broth has different degrees of inhibition on 8 plant pathogenic fungi of rice sheath blight bacteria, pepper anthracnose bacteria, banana wilt bacteria, peanut brown spot bacteria, corn microsporum, sugarcane red rot bacteria, wheat gibberellic disease and wax gourd root rot bacteria, the inhibition rate is 63.26-81.41%, the inhibition rate on corn microsporum and peanut brown spot bacteria is more than 80%, the inhibition effect on pepper anthracnose bacteria is the weakest, and the inhibition rate is 63.26%.

TABLE 2 antagonistic Effect of Strain F13 on plant fungal diseases

3.4 Strain F13 drug sensitivity test results

The results of drug sensitivity experiments on F13 by using 15 antibiotics are shown in Table 3, and F13 is highly sensitive to norfloxacin, kanamycin, gentamicin and enrofloxacin, moderately sensitive to nalidixic acid and streptomycin, and resistant to 7 antibiotics such as ampicillin, rifampicin and amoxicillin.

TABLE 3F13 results of drug susceptibility testing

Note: s (d >15mm) indicates high sensitivity; i (d is more than or equal to 10mm and less than or equal to 15mm) represents moderate sensitivity; r (d is more than or equal to 0mm and less than 10mm) represents low sensitivity or drug resistance.

3.5 results of siderophore production by Strain F13

As a result, as shown in FIG. 8, F13 was cultured on a CAS medium plate at 36 ℃ for 7d, and an orange halo was formed around the colony (FIG. 8), indicating that the strain was able to produce siderophores.

3.6 quantitative analysis and identification of shenqinmycin produced by strain F13

The yields of shenqimycin in KB medium and in soya bean meal medium at different temperatures (28 and 36 ℃) of strain F13 are shown in FIG. 8. No matter under the conditions of 28 ℃ and 36 ℃, the yield difference of the strain F13 in the two culture media is remarkable, the yield of the PCA in a KB culture medium is the highest and is 61.5mg/L, and the yield of the PCA in a soybean meal soaking culture medium is the lowest and is 4.51 mg/L. Therefore, the strain F13 has the highest PCA yield (61.5mg/L) in KB medium at 28 ℃. In the two culture media, the yield of PCA is remarkably different and has inconsistent change trend in different temperatures, and in the KB culture medium, the yield of PCA is reduced along with the increase of the temperature; in the soybean extract medium, the yield of PCA increased with increasing temperature.

3.7 Primary prevention and treatment effects of Strain F13 on powdery mildew of Charpy grape and powdery mildew of kidney bean in field

Powdery mildew is a common plant disease, is caused by infection of fungi, mainly harms leaves and leaf tips of plants, and also harms fruits and stems of plants. As shown in tables 4 and 5, the strain F13 has good control effects on grape powdery mildew and kidney bean powdery mildew, can effectively inhibit the spreading of the powdery mildew, and has relative control effects of 72.28 percent and 71.78 percent respectively, which are equivalent to the control effects of 75 percent chlorothalonil wettable powder serving as a control chemical agent, and have relative control effects of 70.38 percent and 72.98 percent respectively.

As can be seen from fig. 10 and 11, the disease of the leaf powdery mildew of the summer black grapes has substantially disappeared by 7 days after the 50-fold diluted strain fermentation broth is sprayed; the 9 th day after spraying the strain fermentation liquor diluted by 50 times, the disease of powdery mildew of the kidney bean leaves has basically disappeared, which shows that the strain F13 has obvious control effect on the powdery mildew of summer black grapes and the powdery mildew of the kidney bean.

TABLE 4 prevention and treatment effect of fermentation liquor of strain F13 on powdery mildew of summer black grapes

TABLE 5 prevention and treatment effect of fermentation liquor of strain F13 on powdery mildew of kidney beans

3.8 Effect of F13 strain on growth promotion and yield increase of vigna unguiculata

As can be seen from Table 6, the fermentation broth of the strain F13 was applied to beans at a height of 26.7%, a leaf number of 24.4%, and a stem thickness higher than those of the control group, and at a yield of 39.68% higher than that of the control group, respectively, as compared with the control group to which the microbial inoculum was not applied. Therefore, the strain F13 has better growth-promoting and yield-increasing effects on the green beans.

TABLE 6 Effect of the Strain F13 on growth promotion and yield increase of vigna unguiculata

Item	Plant height (cm)	Number of blades (sheet)	Stem diameter (mm)	Fruit yield (Kg)
					Group F13	128.75±15.4	24.88±1.32	8.03±0.72	44.0
Control group	101.61±16.27	20±2.12	7.17±0.66	31.5

3.9 Effect of the Strain F13 on the absorption of phosphorus and potassium by vigna unguiculata plants

As can be seen from FIG. 12, the phosphorus and potassium absorption of the green bean plants by the applied strain F13 is 11.5% and 46.8% higher than that of the control group without the microbial inoculum. Therefore, the application of the strain F13 can promote the absorption of nutrient elements by the green bean plants.

Claims

1. A plant rhizosphere growth promoting strain which is classified and named as pseudomonas aeruginosa (pseudomonas aeruginosa)Pseudomonas aeruginosa) Strain number F13, which is deposited in the Guangdong province culture Collection of microorganisms with the deposit number GDMCC No. 61146 and the deposit date of 2020, 8 months and 14 days.

2. Use of the plant rhizosphere growth promoting strain F13 of claim 1 for solubilizing phosphorus or potassium.