Banana endophytic bacillus velezensis jdb15 and application thereof

Abstract

The present application belongs to the field of microorganisms, and particularly relates to a banana endophytic bacillus velezensis JDB15 and application thereof. Foc 4efficient inhibition, banana growth promotion and broad-spectrum antagonistic characteristics of various pathogenic bacteria, can inhibit the occurrence of corn small spot, tomato wilt, tobacco gray mold, peach anthracnose, and has good broad-spectrum effect. At the same time, the strain can also kill nematodes, has extensive biocontrol activity, and can be further developed, providing a sustainable and green solution for the prevention and control of banana wilt and other diseases and pests.

Description

Technical Field

[0001] This invention belongs to the field of microbiology, specifically relating to a banana endophytic Bacillus berleisii JDB15 and its applications. Background Technology

[0002] banana( Musa Banana wilt (Fusarium wilt) is one of the world's most important economic crops, widely cultivated in approximately 130 countries and regions, with an annual output exceeding 100 million tons, making it a pillar industry of agricultural economies in tropical and subtropical regions. However, banana wilt disease (Fusarium wilt) Fusarium The spread of *Fusarium oxysporum* (Wilt of Banana) seriously threatens the sustainable development of the global banana industry. This disease is caused by *Fusarium oxysporum* var. *cubicans* (specific strain). Fusarium oxysporum f. sp. cubense , Foc Fusarium wilt (Fusarium wilt) is a typical soil-borne fungal disease causing vascular necrosis. First discovered in Hawaii, USA in 1904, it quickly spread to banana-producing regions worldwide. Once an outbreak occurs, the incidence rate can reach 10%-40%, exceeding 90% in severely affected areas, leading to significant yield reductions or even complete abandonment of banana plantations. It is characterized by its devastating impact and difficulty in eradication, causing enormous economic losses to banana farmers globally. Even more serious is the presence of physiological race 4 of Fusarium wilt (Fusarium wilt). Foc 4) It can infect multiple cultivars, including Cavendish bananas, which account for over 95% of the global banana trade, meaning the disease threat has reached the core of the industry. Currently, banana wilt control mainly relies on chemical pesticides, but long-term use has drawbacks such as pesticide residues, poor environmental compatibility, and low control efficiency. Biological control technology, with microbial agents at its core, is considered an ideal alternative to chemical pesticides. Among these, plant endophytes, due to co-evolution with their hosts, possess advantages such as strong environmental affinity, high colonization stability, and diverse metabolic functions. However, some strains isolated from non-banana hosts (such as apples and vegetables) have varying colonization efficiency in banana vascular bundles. Foc The inhibitory effect of strain 4 is insufficient, and live microbial preparations are easily affected by storage conditions, resulting in short shelf life that restricts industrial application. Furthermore, most strains focus on disease control, and their effects on banana growth promotion and nutrient metabolism regulation have not been fully explored. Therefore, given these issues, developing antagonistic strains against banana wilt disease is of significant importance to the development of the banana industry. Summary of the Invention

[0003] This invention provides a banana endophytic Bacillus beryl JDB15 and its application, which has the following advantages: Foc 4. Highly effective inhibition, banana growth promotion and broad-spectrum antagonistic properties against multiple pathogens.

[0004] The technical solution of this invention is implemented as follows:

[0005] The first aspect of the present application is a banana endophytic Bacillus velezensis JDB15, named as Bacillus velezensis and preserved in Guangdong Microbial Culture Collection Center with a preservation number of GDMCC No: 66431.

[0006] The second aspect of the present application is to provide a fermentation broth of the banana endophytic Bacillus velezensis JDB15 according to the first aspect of the present application or a filtrate of the fermentation broth.

[0007] The third aspect of the present application is to provide a preparation containing the banana endophytic Bacillus velezensis JDB15 according to the first aspect of the present application or the fermentation broth according to the second aspect of the present application.

[0008] The fourth aspect of the present application is to provide an application of the banana endophytic Bacillus velezensis JDB15 according to the first aspect of the present application or the fermentation broth according to the second aspect of the present application or the preparation according to the third aspect of the present application in preparing a preparation for antagonizing Fusarium oxysporum f. sp. cubense, Botrytis cinerea, Fusarium graminearum, Magnaporthe oryzae, Sclerotinia sclerotiorum, Rhizoctonia solani, Fusarium oxysporum f. sp. cucumerinum, Sclerotium rolfsii, Fusarium fujikuroi, Xanthomonas campestris, Monilinia fructicola, Monilinia laxa, Fusarium solani f. sp. glycines, Fusarium fujikuroi f. sp. lycopersici, Alternaria alternata, Cochliobolus sativus, Xanthomonas albilineans and Pseudomonas syringae.

[0009] The fifth aspect of the present application is to provide an application of the banana endophytic Bacillus velezensis JDB15 according to the first aspect of the present application or the fermentation broth according to the second aspect of the present application or the preparation according to the third aspect of the present application in preparing a preparation for preventing and treating diseases caused by Fusarium oxysporum f. sp. cubense, Botrytis cinerea, Fusarium graminearum, Magnaporthe oryzae, Sclerotinia sclerotiorum, Rhizoctonia solani, Fusarium oxysporum f. sp. cucumerinum, Sclerotium rolfsii, Monilinia fructicola, Monilinia laxa, Fusarium solani f. sp. glycines, Fusarium fujikuroi f. sp. lycopersici, Alternaria alternata, Cochliobolus sativus, Xanthomonas albilineans and / or Pseudomonas syringae or for preventing and treating nematodes.

[0010] The sixth aspect of the present application is to provide an application of the banana endophytic Bacillus velezensis JDB15 according to the first aspect of the present application or the fermentation broth according to the second aspect of the present application or the preparation according to the third aspect of the present application in preparing a preparation for improving the resistance of banana plants to Fusarium oxysporum f. sp. cubense, inhibiting the hyphal growth of Fusarium oxysporum f. sp. cubense and inhibiting the spore germination of Fusarium oxysporum f. sp. cubense.

[0011] The seventh aspect of the present application is to provide an application of the banana endophytic Bacillus velezensis JDB15 according to the first aspect of the present application or the fermentation broth according to the second aspect of the present application or the preparation according to the third aspect of the present application in promoting the growth of banana plants.

[0012] Furthermore, the Banana Endophytic Bacillus berreatus JDB15 described in the first aspect of the present invention, or the fermentation broth described in the second aspect of the present invention, or the preparation described in the third aspect of the present invention, can increase the stem diameter, plant height, leaf area, plant fresh weight, plant dry weight, and / or root number of banana plants.

[0013] The eighth aspect of the present invention is to provide the use of Bacillus endophyticus of banana JDB15 as described in the first aspect of the present invention, or the fermentation broth as described in the second aspect of the present invention, or the formulation as described in the third aspect of the present invention, in the preparation of formulations that secrete protease, cellulase, amylase, pectinase, auxin, nitrogen fixation, potassium solubilization, organophosphate solubilization and / or chitinase activity.

[0014] The ninth aspect of the present invention is to provide the use of Bacillus venereum JDB15 of banana as described in the first aspect of the present invention, or the fermentation broth as described in the second aspect of the present invention, or the preparation as described in the third aspect of the present invention in the preparation of a formulation that enhances the stress resistance of banana plants.

[0015] Furthermore, the Banana Endophytic Bacillus berreatus JDB15 described in the first aspect of the present invention, or the fermentation broth described in the second aspect of the present invention, or the preparation described in the third aspect of the present invention, can increase the peroxidase activity and / or catalase content in normal banana plants and banana plants infected with Fusarium wilt.

[0016] The beneficial effects of this invention are:

[0017] This invention isolates a novel endophytic Bacillus belye JDB15 from banana plants. This strain possesses... Foc 4. This strain exhibits highly effective inhibition, banana growth promotion, and broad-spectrum antagonism against multiple pathogens. It can suppress the incidence of rice blast, corn leaf blight, tomato wilt, tobacco gray mold, and peach anthracnose. It has a good broad-spectrum effect in inhibiting the incidence of various pathogenic fungi. At the same time, this strain can also kill nematodes and has broad biocontrol activity. Further development is possible to provide a sustainable and green solution for the prevention and control of banana wilt and other diseases and pests. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 For strain JDB15Foc 4 Mycelial antagonism experiment results.

[0020] Figure 2 16s amplification results of strain JDB15.

[0021] Figure 3 Phylogenetic tree of strain JDB15.

[0022] Figure 4 Cultural characteristics of strain JDB15 on seven different media respectively.

[0023] Figure 5 Gram staining results of strain JDB15.

[0024] Figure 6 Physiological activity determination results of strain JDB15.

[0025] Figure 7 NaCl tolerance experiment results of strain JDB15.

[0026] Figure 8 Broad-spectrum fungistatic activity determination results of strain JDB15.

[0027] Figure 9 Inhibitory activity determination results of strain JDB15 on PX099 and XOC.

[0028] Figure 10 Inhibitory activity determination results of filtrate of fermentation broth of strain JDB15 on spore germination of 4. Foc 4.

[0029] Figure 11 Mycelial inhibition activity determination results of filtrate of fermentation broth of strain JDB15 on 4. Foc

[0030] Spore germination inhibition activity determination results of filtrate of fermentation broth of strain JDB15 on 4. Figure 12 Foc Preventive effect of fermentation broth of strain JDB15 on banana fusarium wilt.

[0031] Figure 13 Growth-promoting effect of fermentation broth of strain JDB15 on banana plants.

[0032] Figure 14 Influence of fermentation broth of strain JDB15 on banana plant growth.

[0033] Figure 15 Enzyme activity detection results of fermentation broth of strain JDB15 on banana seedlings.

[0034] Figure 16

[0035] ​​Figure 17 The prevention and treatment effect of the fermentation liquor of strain JDB15 on barley rice blast.

[0036] Figure 18 The prevention and treatment effect of the fermentation liquor of strain JDB15 on corn small spot.

[0037] Figure 19 The prevention and treatment effect of the fermentation liquor of strain JDB15 on nematodes.

[0038] Figure 20 The prevention and treatment effect of the fermentation liquor of strain JDB15 on tomato wilt.

[0039] Figure 21 The prevention and treatment effect of the fermentation liquor of strain JDB15 on tobacco gray mold.

[0040] Figure 22 The prevention and treatment effect of the fermentation liquor of strain JDB15 on peach anthracnose.

[0041] The banana endophytic Bacillus velezensis JDB15 described in the application is named as: Bacillus velezensis , and is registered and preserved in Guangdong Microbial Culture Collection Center, with a preservation number of GDMCC No: 66431, a preservation date of May 28, 2025, and a preservation address of 5th Floor, Building 59, 100, Xianlie Middle Road, Guangzhou, Institute of Microbiology, Guangdong Academy of Sciences. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0043] Embodiment 1

[0044] 1. Isolation of endophytes and determination of antifungal activity

[0045] First, some endophyte strains are isolated from banana root systems by using relevant isolation procedures of endophytes. The banana root system sample is collected from the greenhouse of Huazhong Agricultural University, No. 1, Shizishan Street, Hongshan District, Wuhan, Hubei Province (longitude: 114.3E, latitude: 30.4N).

[0046] Banana endophytic bacteria were isolated using tissue dilution separation method. Banana plants with good growth and no disease spots were selected for isolation experiment. Before the experiment, forceps, blades, filter paper, coating rods, 2 ml centrifuge tubes, and small steel balls were sterilized with high-temperature steam. 50% glycerol, 75% ethanol, and 1% hypochlorous acid solution were prepared. Surface disinfection: first, rinse the banana roots with tap water, cut the banana roots into small pieces, and perform surface disinfection in a sterile operation table. First, wash with running water, dry, then move to the clean bench and rinse with 75% ethanol for 1 min. Rinse with sterile water once, then rinse with 1% sodium hypochlorite for 30 seconds. Rinse with sterile water 3 times, and filter paper to absorb the surface moisture. Take 100 µL of the supernatant from the last sterile water wash and spread it on PDA and LB media. Do 3 blank controls, and place them in a 28°C and 30°C incubator for 1-5 days. If no colonies are observed, it indicates that the banana root surface has been completely disinfected. Set up a concentration gradient: place 0.1 g of banana root tissue in a 2 ml EP tube with a steel ball, and shake it thoroughly with a vortex shaker. Dilute the supernatant with ultrapure water, and set up 4 concentration gradients -1 -10 -4 . Dilute the solution and spread it on the plate: make three repeats for each gradient, take 0.1 ml and spread it on the LB plate, and place it in a 30°C incubator for 1-2 days. Observe the number of colonies during this period. Purification culture: when various morphological colonies grow on the plate, use a sterile toothpick to select obviously different strains and activate them on LB. Preservation of endophytic bacteria: pick single colonies in an EP tube containing LB liquid medium, 28°C shaking bed, 180 r / min shaking culture for 12 h, add 50% glycerol 1:1, mix well, and store at -70°C (can be stored for half a year at -20°C) for the next experiment.

[0047] Then the inhibitory ability of the isolated strains on Foc 4 mycelial growth was determined. Antagonistic bacteria Foc 4 were screened by plate antagonistic test:

[0048] Quantitatively pour 10 mL PDA medium into a 6 cm culture dish for use. Take fresh purified bacterial strains and vertically parallelly draw lines on both sides of the poured PDA plate 1.5 cm from the center, and incubate at 30°C for 1 day. After the colonies grow, punch a hole with a 5 mm puncher at the edge of the Foc 4 strain mycelium, inoculate the mycelial block in the center of the PDA plate, and incubate at 25°C to observe the confrontation. Draw a line with sterile water as a control. When the Foc 4 strain grows on the PDA plate, observe whether there is an antagonistic zone. If there is antagonism, measure the width of the antagonistic zone and identify it. Select strong antagonistic strains for the next experiment.

[0049] During the experiment, it was found that the endophyte numbered JDB15 showed obvious antagonism to Foc 4mycelial growth (P<0.01) Figure 1 , with an inhibition rate of 80.34%.

[0050] 2. Analysis of the growth characteristics of JDB15

[0051] The genomic DNA of strain JDB15 was extracted using the Becterial DNA Kit reagent kit of Omega Company. The extracted genomic DNA was used as a template, and the target fragment was amplified by PCR using bacterial 16S rDNA gene primers: 27F 5'-AGAGTTTGATCCTGGCTCAG-3' and 1492R 5'-TACGGCTACCTTGTTACGACTT-3'. The PCR reaction system was as follows:

[0052] The amplification conditions of PCR were as follows: 95℃ pre-denaturation for 5 min; 95℃ denaturation for 30 sec, 56℃ annealing for 30 sec, 72℃ extension for 30 sec, 32 cycles; 72℃ extension for 8 min, and 12℃ stop. A sequence of about 1500 bp was obtained. Figure 2 By comparing the 16S RNA sequence of strain JDB15 in the GenBank database, it was found that it had the highest similarity with Bacillus velezensis.

[0053] Through comparison with the local database, 19 strains closest to the species level were selected based on 31 housekeeping genes (dnaG, frr, infC, nusA, pgk, pyrG, rplA, rplB, rplC, rplD, rplE, rplF, rplK, rplL, rplM, rplN, rplP, rplS, rplT, rpmA, rpoB, rpsB, rpsC, rpsE, rpsI, rpsJ, rpsK, rpsM, rpsS, smpB, tsf), and a phylogenetic tree was constructed by MEGA 6.0 software by selecting the NJ (Neighbor-Joining) method (Genome Sequencing of Meiji) Figure 3 ).

[0054] The above can determine JDB15 as Bacillus velezensis. In order to further observe its morphological changes, the bacterial body is observed by scanning electron microscope, and it is found that the length of the bacterial body is 1.20 to 1.80 μm, the width is 0.5 to 0.75 μm, the surface of the bacterial body is smooth, and is accompanied by filamentous body, Bacillus velezensis can secrete extracellular polymers (such as polysaccharides, proteins or DNA) to form filamentous network, connect multiple bacterial bodies or wrap bacterial groups to form biofilm. It can also secrete antibacterial substances (such as lipopeptides), extracellular polymers (EPS) to form filamentous structure to wrap bacterial bodies.

[0055] The strain JDB15 is cultured on seven kinds of culture media respectively, and the cultured morphology is recorded, and the specific culture media include LB, PDA, TSA, NA, R2A, Gause's No. 1, King B culture medium Figure 4 )。

[0056] LB culture medium: tryptone 10g, yeast extract 5g, sodium chloride 10g, agar 15g.

[0057] PDA culture medium: potato 200g, glucose 20g, agar 15g.

[0058] TSA culture medium: tryptone 15g, soybean peptone 5g, sodium chloride 5g, agar 15g.

[0059] NA culture medium: peptone 10g, beef powder 3g, sodium chloride 5g, agar 15g.

[0060] R2A culture medium: yeast extract powder 0.5g, peptone 0.5g, casein hydrolysate 0.5g, glucose 0.5g, soluble starch 0.5g, potassium hydrogen phosphate 0.3g, sodium pyruvate 0.3g, magnesium sulfate 0.024g, agar 15g.

[0061] Gause's No. 1 culture medium: soluble starch 20g, potassium nitrate 1g, potassium hydrogen phosphate 0.5g, magnesium sulfate 0.5g, sodium chloride 0.5g, ferrous sulfate 0.01g, agar 15g.

[0062] King B medium: Proteose peptone 20.0 g, potassium phosphate dibasic 1.5 g, sulfuric acid 1.5 g, agar 15 g. On PDA, LB, TSA, NA and King B medium, the colonies appear light yellow, show beige on R2A medium, and appear white on Gause's No. 1 medium. On LB medium, a pungent odor and biofilm are produced, the colonies have the largest diameter of the raised, and a large amount of bacterial metabolites are observed, showing mucous and semi-transparent water spot-like products. A special odor can be smelled on all media, and multiple notches on the colony edge, irregular growth, rough appearance, opacity and wrinkled surface are observed, which can be used as the identification standard of Bacillus. By Gram staining method, it is found that the bacterial cells of JDB15 appear purple, and it is identified as a Gram-positive strain. Figure 5 Therefore, in summary, the JDB15 strain is identified as Bacillus velezensis, named: Bacillus velezensis and registered and preserved in Guangdong Microbial Culture Collection Center, with the preservation number GDMCC No: 66431, the preservation date May 28, 2025, and the preservation address at the 5th floor of Building 59, 100 Middle Liangma Street, Guangzhou, Institute of Microbiology, Guangdong Academy of Sciences.

[0063] 3. Physiological and biochemical characteristics and growth-promoting properties of JDB15

[0064] Cellulose Congo Red Medium: Potassium dihydrogen phosphate 1 g, ammonium sulfate 2 g, magnesium sulfate 0.5 g, CMC-Na 2 g, sodium chloride 0.5 g, Congo red 0.4 g, agar 15 g, distilled water 1000 mL.

[0065] Amylase detection medium: soluble starch 2 g, beef extract 10 g, glucose 10 g, peptone 7 g, agar 18 g, deionized water 1000 mL.

[0066] Pectinase detection medium: glucose: 20 g, pectin 5 g, agar powder 15 g, potato extract 200 g, cut potato boiled for 30 minutes, filter the juice and make up to 1 L with water.

[0067] Protease detection medium: peptone 5 g, beef extract 3 g, sodium chloride 5 g, agar 15 g, skim milk powder: 10 g, distilled water 1 L.

[0068] Iron siderophore detection medium: 60.5 mg Chrome Azurol-S, 72.9 mg cetyltrimethylammonium bromide, 2.645 mg iron chloride hexahydrate, 295.25 mg sodium phosphate dibasic dihydrate, 1213.5 mg disodium phosphate dehydrate, 125 mg ammonium chloride, 37.5 mg potassium phosphate monobasic, 62.5 mg sodium chloride, 15 g agar, pH 6.8 ± 0.1, 1000 mL distilled water.

[0069] Ashby solid medium (nitrogen fixation): potassium phosphate monobasic 0.2 g, magnesium sulfate 0.2 g, sodium chloride 0.2 g, calcium carbonate 5 g, mannitol 10 g, calcium sulfate dihydrate 0.1 g, agar 15 g, pure water 1 L, pH 7.0-7.5.

[0070] Pikovskaya medium (inorganic phosphorus): glucose 10.0 g, ammonium sulfate 0.5 g, sodium chloride 0.3 g, magnesium sulfate heptahydrate 0.3 g, manganese sulfate monohydrate 0.03 g, potassium chloride 0.3 g, ferrous sulfate heptahydrate 0.03 g, tricalcium phosphate 5.0 g, yeast extract 0.5 g (optional), agar 15.0 g, pure water 1 L, pH 7.0 ± 0.2.

[0071] Monch organic phosphorus medium: glucose 10.0 g, ammonium sulfate 0.5 g, sodium chloride 0.3 g, magnesium sulfate heptahydrate 0.3 g, manganese sulfate monohydrate 0.03 g, potassium chloride 0.3 g, ferrous sulfate heptahydrate 0.03 g, lecithin 2.0 g, yeast extract 0.5 g (optional), agar 15.0 g, pure water 1 L, pH 7.0 ± 0.2 g

[0072] Chitinase detection medium: yeast extract 5 g, peptone 5 g, NaCl 5 g, chitin 10 g, agar 15-20 g, distilled water 1000 ml, pH 7.0-7.2.

[0073] Glucan agar medium: Pachyman powder 4.0 g, disodium hydrogen phosphate 17.9 g, potassium dihydrogen phosphate 6.8 g, yeast extract 6.7 g, aniline blue 0.06 g, agar 15 g, distilled water to 1000 mL, pH 7.2.

[0074] Alexandrov medium: disodium hydrogen phosphate 2 g, potassium feldspar powder 1 g, magnesium sulfate heptahydrate 0.5 g, calcium carbonate 0.1 g, ferric chloride 0.05 g, sucrose 5 g, agar 15 g, pure water 1000 mL.

[0075] (1) Starch hydrolysis experiment: JDB15 bacteria were inoculated in the medium containing starch and placed in a 28°C incubator for 3 days of culture. The colonies were stained with iodine solution. If there is a clear transparent circle around the colonies, it is a positive bacteria.

[0076] (2) Cellulase determination method: according to the above method, the strain JDB15 was inoculated on the CMC plate, and after 3 d in the 28°C incubator, an appropriate amount of Congo red solution (1 mg / mL) was poured onto the plate and stained for 15 min. Then wash with sodium chloride solution (1 mol / L) for several times, observe whether there is a yellow halo around the colonies, if there is, it indicates that the strain can produce cellulase, measure and record the diameter of the halo.

[0077] (3) Pectinase determination method: according to the above method, the strain JDB15 was inoculated on the pectin medium plate, and after 3 d in the 28°C incubator, the colonies were stained with iodine solution. If there is a clear transparent circle around the colonies, it is a positive bacteria.

[0078] (4) Protease determination method: sterile filter paper disc was placed in the center of skim milk agar plate, 10 μL of the test strain cultured in LB for 24 h was inoculated slowly on the filter paper disc. The plate was placed in a 28°C incubator for 3 d. If a transparent circle can be formed around the colonies, the strain can produce protease; measure and record the diameter of the transparent circle.

[0079] (5) Iron carrier determination method: CAS plate was used to detect the production of iron carrier. The strain was inoculated in the center of CAS plate and incubated at 28°C for 3-5 d. Whether there is an orange halo around the colonies was observed. If there is, it indicates that the strain can secrete iron carrier, and the diameter of the halo is measured and recorded.

[0080] (6) Auxin IAA determination method: colorimetric method was used to quantitatively determine the IAA production. The strain was inoculated in 4 mL LB medium containing 40 mg tryptophan, and LB medium without strain was used as negative control. After incubation at 28°C for 48 h, 1.5 mL of culture solution was centrifuged at 12100 rpm for 10 min. 0.5 mL of supernatant was mixed with 1 mL of salkowski reagent in a 1.5 mL tube, and incubated at 25°C in the dark for 30 min. Whether IAA was produced was determined according to the color change.

[0081] (7) Inorganic phosphorus determination method: JDB15 was activated by LB solid medium and cultured at 28°C for 48 h. Then the colonies were picked with sterile toothpicks and inoculated on Pikovskaya medium in a clean bench.

[0082] (8) The determination method of organophosphorus is to activate JDB15 by LB solid medium, cultivate for 48 h at 28°C, then pick the colonies on the ultra-clean workbench and point them on the Monkhina organophosphorus medium with a sterile toothpick.

[0083] (9) The determination method of nitrogen fixation is to activate JDB15 by LB solid medium, cultivate for 48 h at 28°C, then pick the colonies on the ultra-clean workbench and point them on the Ashby solid medium with a sterile toothpick.

[0084] (10) The determination method of potassium is to activate JDB15 by LB solid medium, cultivate for 48 h at 28°C, then pick the colonies on the ultra-clean workbench and point them on the Alexandrov medium with a sterile toothpick.

[0085] (11) The determination method of chitinase detection is to use LB plate to streak the bacteria, cultivate for 48 h at 28°C, use about 10 ml sterile water to smear the plate, prepare a bacterial suspension, then point 1 μl on the colloidal chitin plate, and cultivate until a transparent circle appears.

[0086] (12) The determination method of glucanase detection medium is to activate JDB15 by LB solid medium, cultivate for 48 h at 28°C, then pick the colonies on the ultra-clean workbench and point them on the glucan agar medium with a sterile toothpick.

[0087] The determination results are shown in Figure 6 and Table 1. The strain JDB15 has a strong ability to secrete protease, and the diameter of the transparent circle is 25.6 mm. The ability to secrete cellulase is strong, and the halo diameter is 40.5 mm. The activities of secreted amylase (diameter 30.4 mm) and pectinase (diameter 35.5 mm) are also strong. It can produce IAA, has no siderophore production ability, has nitrogen fixation and potassium solubilization abilities, has chitinase production and organophosphorus solubilization abilities, and has no inorganic phosphorus solubilization and β1,3-glucanase production abilities.

[0088] Table 1. Physiological and biochemical determination results of strain JDB15

[0089] Physiological and biochemical Results Growth-promoting properties Results Amylase + IAA + Cellulase + Inorganic phosphorus - Pectinase + Organic phosphorus + Protease + Nitrogen fixation + Siderophore production - Potassium solubilization + Chitinase + Beta 1,3-glucanase -

[0090] (13) NaCl tolerance experiment: In order to explore the tolerance of the strain to NaCl, LB medium containing different NaCl concentrations (0%, 2%, 4%, 6%, 8%, 10%) was prepared to ensure that the other nutritional conditions were consistent. The strain was inoculated into the medium, and it was placed in a 28°C incubator for 3 days. After the incubation, the growth of the strain was observed, and its growth ability under different NaCl concentrations was recorded to determine the upper and lower concentration limits of the strain to NaCl. The results are shown in Figure 7 and Table 2.

[0091] Table 2 NaCl tolerance experiment results

[0092] NaCl concentration Results 0 + 2% + 4% + 6% + 8% + 10% +

[0093] 4. Broad-spectrum fungistatic activity assay of JDB15

[0094] Test pathogenic fungi: Botrytis cinerea, Fusarium graminearum, Magnaporthe grisea, Sclerotinia sclerotiorum, Rhizoctonia solani, Fusarium oxysporum f. sp. cubense, Sclerotium rolfsii, Fusarium fujikuroi, Xanthomonas campestris pv. campestris, Xanthomonas oryzae pv. oryzae, Alternaria solani, Pythium aphanidermatum, and Bipolaris maydis. B. cinerea, F. graminearum, M. grisea, B. maydis, and F. fujikuroi were preserved in the laboratory of Professor Chen Xiaolin, Yanglong, Sclerotinia sclerotiorum, Rhizoctonia solani, F. oxysporum f. sp. cubense, and S. rolfsii were provided by Professor Yanglong, Xanthomonas campestris pv. campestris and Xanthomonas oryzae pv. oryzae were provided by Professor Li Guotian, and A. solani and Pythium aphanidermatum were provided by Professor Liang Wensheng.

[0095] Broad-spectrum fungal antagonism: Each strain was activated on PDA medium one week in advance; fresh JDB15 bacterial strain was prepared one day in advance, and inoculation work was started in a clean bench. First, a 5-mm-diameter sterilized puncher was used to take fresh mycelium cakes from the edge of the colonies of 13 pathogenic fungi cultured for 5 days, which were inoculated in the center of a 6-cm-diameter PDA culture dish as target fungi. A sterilized toothpick was used to dip a single colony of activated JDB15 strain and draw lines vertically at two positions 1.5 cm from the center of the fungal cake. Banana wilt fungus was inoculated as a blank control. The culture was incubated at 25°C for 2-5 days, photographed, and the horizontal diameters of the pathogenic fungi in the control and treatment groups were measured to calculate the inhibition rate. The inhibition rate (%) = control colony diameter - treatment colony diameter / control colony diameter x 100%. Each group was repeated 5 times, and 3 biological repeated experiments were performed.

[0096] Broad-spectrum bacterial antagonism: Each strain was activated in LB liquid medium two days in advance, and fresh JDB15 bacterial strain fermentation broth was prepared one day in advance. Inoculation work was started in a clean bench. First, a bottle of LB solid medium was melted, and after it cooled down to a temperature that was not too hot to touch, PX099 and XOC bacterial liquid were added and poured onto the plate. An Oxford cup puncher was used to add different amounts of JDB15 fermentation broth (20 μl, 30 μl, 40 μl) into the wells, with LB medium as the control group (CK). The culture was incubated at 30°C for 2 days, and photographed.

[0097] Preparation method of fermentation broth of strain JDB15: inoculate the single colony of the strain into 2 mL of liquid LB medium, shake culture at 28°C and 180 r / min for 12 h until the bacterial solution is turbid, take 100 μL of the bacterial solution and add it into 100 mL of liquid LB medium for further fermentation, and shake culture the fermentation broth until the OD 600 = 1, dilute to 1 × 10 7 CFU / ml, and reserve.

[0098] The results are shown in Figure 8 , Figure 9 and Table 3, and the strain JDB15 has certain inhibitory effect on 13 kinds of plant pathogenic fungi (Table 3), has good broad-spectrum antifungal effect, and the inhibitory effect is obvious. The strain JDB15 also has obvious inhibitory effect on PXO99 (Xanthomonas campestris pv. oryzae) and XOC (Xanthomonas campestris pv. campestris) (Table 3). Figure 8 Figure 9

[0099] Table 3 Broad-spectrum antifungal activity determination results of JDB15

[0100] Pathogen Inhibition rate Botrytis cinerea 76.35±1.62% Fusarium graminearum 64.3±1.7% Magnaporthe oryzae 74.5±1.5% Sclerotinia sclerotiorum 65.75±2.25% Rhizoctonia solani 82.47±2.03% Sclerotium rolfsii 78.43±1.67% Fusarium fujikuroi 69.93±1.04% Fusarium oxysporum f. sp. conndensae 71.23±1.65% Monilinia fructicola 72.3±2.11% Gluconectria peucedanoides 71.73±2.17% Fusarium oxysporum f. sp. lycopersici 73.44±2.16% Cochliobolus miyabeana 64.45±3.05% Alternaria alternata 60.45±2.18

[0101] 5. Inhibitory activity determination of fermentation broth filtrate of strain JDB15 on Fusarium oxysporum f. sp. cubense

[0102] Preparation method of fermentation broth filtrate of strain JDB15: centrifuge the fermentation broth in “4” at 8000 r / min for 10 min, take the supernatant and filter twice with a 22 μm sterile filter to obtain the fermentation broth filtrate.

[0103] (1) Experimental method: the control group (4) is PDA medium, and the treatment group (4+JDB15) takes the fermentation broth filtrate and adds it into the cooled PDA medium at a proportion of 10% of the medium volume, pours and solidifies the plate, and then uses a 5 mm puncher to punch the Fusarium oxysporum f. sp. cubense 4 into the center of the PDA, and places it in a 25°C incubator for culture, and after the control group is full, the growth of the treatment group is observed, and the inhibition rate is calculated. Inhibition rate (%) = control colony diameter - treatment colony diameter / control colony diameter × 100%. Foc Foc Foc

[0104] The results show that (Table 4), the inhibition rate of the fermentation broth filtrate of the strain on Fusarium oxysporum f. sp. cubense 4 is 48.85%. Figure 10 Foc 4.

[0105] ​​​​​​(2) Experimental methods: The control group (CK) used PDA medium. For the treatment group (JDB15), the filtrate of the fermentation broth was added to the cooled PDA medium at a ratio of 10% of the medium volume. After the medium solidified, banana wilt pathogens were inoculated into the center of the PDA using a 5mm punch and placed in an incubator at 25℃. After two days of incubation, the tips of the mycelia were obliquely inserted into a glass slide. After 24 hours, the slide was removed and observed under a microscope. The mycelia in this area were cut into 1cm squares with a scalpel blade, placed in electron microscopy fixative, and subjected to gradient centrifugation with different concentrations of ethanol. The samples were then critically dried and sputter-coated with gold. The samples were sent to Wuhan Kerui Nuo Company for testing.

[0106] Experimental results are as follows Figure 11 It can be discovered through microscopic observation Foc Normal hyphae (CK) showed a smooth surface with regular, rounded, and plump tips. In contrast, hyphae treated with JDB15 fermentation broth filtrate had a rough surface, irregular swelling, and broken cell walls. Branching at the hyphal tips was webbed, with spherical and spindle-shaped swellings. SEM analysis revealed that the hyphae in the treated group had smooth surfaces without obvious folds, while the hyphae in the other group exhibited breakage, twisting, and deformation.

[0107] (3) Experimental method: In order to determine the effect of JDB15 fermentation broth filtrate on the Foc 4. The effect of spore germination Foc 4 spore suspension (10 6 The CFU / mL solution was thoroughly mixed with 10% of the volume of the sterile fermentation broth filtrate. Foc 4+JDB15) and an equal volume of sterile water were used as a control (CK). The mixture was added dropwise to a hydrophobic glass slide, placed in a glass dish containing moistened filter paper, and incubated at 28°C for 12 h. Each treatment was set up in 3 biological replicates. The spore germination count and spore germination rate were calculated as follows: Germination rate (%) = (number of germinating spores) / total number of spores × 100%.

[0108] Experimental results ( Figure 12 The germination rate of the control group was around 71%, while the spore germination rate of Foc4 in the JDB15 fermentation broth treatment group was only 22.56%, significantly lower than that of the control group. This indicates that the JDB15 fermentation broth filtrate can significantly inhibit germination. Foc 4. Spore germination.

[0109] 6. Pot inoculation experiment of banana seedlings

[0110] In a greenhouse with an average temperature of 28 °C and a relative humidity of 70%, the strain JDB15 fermentation broth (preparation method as described in "4") and the fermentation broth filtrate were further verified for their control effect on banana fusarium wilt. When the banana seedlings grew to 3-4 true leaves in the seedling bags, they were transplanted into pots. The following three treatments were set up: negative control H2O (sterile deionized water), GFP- Foc 4 (positive control 1.0 × 10 7 CFU / ml), strain JDB15 (1.0 × 10 7 CFU / ml) + GFP- Foc 4 (1.0 × 10 7 CFU / ml), strain JDB15 fermentation broth + GFP- Foc 4 (1.0 × 10 7 CFU / ml) (volume ratio 1:1). First, the strain JDB15 fermentation broth and the fermentation broth filtrate were applied to the roots of the banana plants with injured roots for soaking treatment, and 20 ml of GFP- Foc 4 spore suspension was applied to the roots of the banana plants the next day and 20 ml of strain JDB15 fermentation broth or fermentation broth filtrate was added. 10 plants were used for each treatment.

[0111] According to the description of Himaman et al., (2016), each group of banana seedlings was divided into 5 grades, and the proportion of yellowing leaves in one plant was calculated, 0 grade: healthy plant, 1 grade: 1-25% yellowing leaves, 2 grade: 26-50% yellowing leaves, 3 grade: 51-75% yellowing leaves, 4 grade: more than 75% yellowing leaves. The disease index (DI) of banana fusarium wilt was calculated as follows:

[0112]

[0113] The results show that (Table 6) Figure 13 ), the disease index of banana plants treated with strain JDB15 fermentation broth and fermentation broth filtrate was significantly reduced, indicating that strain JDB15 fermentation broth and fermentation broth filtrate had a significant antagonistic effect on banana fusarium wilt and could reduce the disease index of banana plants.

[0114] 7. Evaluation of the growth promotion effect of banana seedlings

[0115] In a greenhouse with an average temperature of 28 °C and a relative humidity of 70%, the antagonistic bacterial fermentation broth was further verified for its growth promotion effect on banana seedlings. The company's banana seedling bags were purchased and transplanted into pots, and the following two treatments were set up: H2O (sterile deionized water), antagonistic strain JDB15 (1.0 × 10 7(CFU / ml). Bacterial fermentation broth was added every seven days during the treatment. Treatment lasted 30 days, with 10 strains used per treatment.

[0116] The results are as follows Figure 14 and Figure 15 Banana plants treated with strain JDB15 showed significant increases in stem diameter, plant height, leaf area, fresh weight, dry weight, and root number, indicating that JDB15 can promote the growth of banana plants and has a significant growth-promoting effect.

[0117] Experimental methods:

[0118] (1) Plant height: The height of the pseudostem of the banana plant is measured with a 1-meter soft ruler from the part of the pseudostem that just emerges from the soil to the intersection of the first unfolded leaf and the second unfolded leaf.

[0119] (2) Stem diameter: The diameter of the banana seedling stem 2cm above the surface of the sand is measured with an electronic vernier caliper.

[0120] (3) Total leaf area: Based on the predicted "Basrsi" leaf area (MVetal, 1994) regression equation (leaf

[0121] Area (m) 2 =0.0266 + (L*W*0.7629) (r=0.98), where L refers to leaf length (m) and W refers to leaf width (m). The leaf area of ​​the new leaves is calculated (Zhang Zhian et al., 2008). The total area of ​​the new leaves is the sum of the areas of each new leaf.

[0122] (4) Fresh weight of the plant: Pull the banana plant out of the soil with its roots intact, wash the soil off the banana roots with running water, and weigh the banana plant directly.

[0123] (5) Dry weight of the plant: The bananas washed with running water were placed in liquid nitrogen and frozen for 30 minutes, and then taken out and weighed.

[0124] (6) Number of roots: Wash the root system with running water and count the number of the thicker roots.

[0125] 8. Detection of enzyme activity in banana seedlings

[0126] In a greenhouse with an average temperature of 28 ℃ and a relative humidity of 70%, the effect of fermentation broth of strain JDB15 on the enzyme activity of banana plants infected with Fusarium wilt was further verified. Banana seedling bags purchased from the company were transplanted into pots, and the following two treatments were set up: Day 0 was the treatment, with the addition of water and fermentation broth of strain JDB15; CK was the water treatment. After sampling on the third day, the fermentation broth of strain JDB15 was added. Foc 4. Infection was performed using spore suspension. Results were as follows: Figure 16 As shown.

[0127] Results show that, application of JDB15 fermentation liquor, in addition to the control group (WT), can significantly reduce the number of disease spots and disease area of banana plants, reduce the incidence of banana plants. Foc 4 Spore liquid before and after, can significantly improve the POD (peroxidase) activity and CAT (catalase) content in banana plants. It is shown that application of strain JDB15 fermentation liquor, not only can improve the POD activity and CAT content of banana plants growing normally, but also can significantly improve the POD activity and CAT content of banana seedlings infected with banana wilt, can significantly improve the stress resistance and resistance to banana wilt of banana seedlings. And for banana plants infected with banana wilt, the effect of improving stress resistance is more significant.

[0128] Experimental method: POD activity was determined by peroxidase (POD) activity assay kit (item number: BC0090, manufacturer: Solabio), and CAT content was determined by catalase (CAT) activity assay kit (item number: BC0205, manufacturer: Solabio).

[0129] 9. The effect of JDB15 on other diseases and pests

[0130] (1) Rice blast

[0131] Prepare a rice blast spore suspension with 0.05% (v / v) Tween 20, adjust the spore concentration to 1 x 10 5 6 / mL, mix this spore solution with water at a volume ratio of 1:1 as a control group (WT), mix this spore solution with JDB15 at a volume ratio of 1:1 as an experimental group (WT+JDB15), and the negative control is water (H2O) treatment. Then spray it on the front of the barley leaves grown for 7 days, seal with plastic wrap, treat at 28℃ in the dark for 24 h, then expose to light, tear off the plastic wrap and ventilate after 48 d, pay attention to moisture, observe the inoculation results and take pictures after 5 d. Figure 17 Up

[0132] Cut the barley leaves with scissors to the appropriate size, inoculate the barley leaves with 10 μl of the above spore mixture using a gun, treat at 28℃ in the dark for 24 h, then expose to light, tear off the plastic wrap and ventilate after 48 d, pay attention to moisture, observe the inoculation results and take pictures after 5 d. Figure 17 Down

[0133] The results are shown in Figure 17 Table 2, inoculation of strain JDB15 fermentation liquor, compared with the control group inoculated with spore suspension, can significantly reduce the number of disease spots and disease area of barley leaves, reduce the incidence of rice blast of barley leaves.

[0134] (2) Corn small spot

[0135] After sporulation, the corn leaf blight pathogen was washed away with a 0.05% (v / v) Tween 20 aqueous solution to prepare a suspension, and the concentration was adjusted to 1×10⁻⁶. 4 / mL. Corn seedlings with similar growth and a seedling age of 7 days were selected as test subjects. This spore solution was mixed with water (WT) and JDB15 (WT+JDB15) at a volume ratio of 1:1. The leaves were lightly scratched with a syringe needle, and the spore solution was applied to the scratched areas with a pipette tip. Photos were taken after the disease had developed. Results are as follows: Figure 18 After inoculation with fermentation broth containing strain JDB15 (WT+JDB15), the area of ​​corn leaf spot lesions was significantly reduced compared to the WT group which only added water, indicating that strain JDB15 has a significant inhibitory effect on corn leaf spot.

[0136] (3) Nematodes

[0137] The washed nematodes were placed in 96-cell plates, and 100 μL of water (WT) and fermentation broth of strain JDB15 (JDB15) were added respectively. The plates were incubated at 28°C for 12 h and observed using an optical microscope. Results are as follows: Figure 19 The addition of JDB15 fermentation broth (JDB15) significantly increased the mortality rate of nematodes, which was significantly higher than that of the WT group, indicating that strain JDB15 has the effect of killing nematodes.

[0138] (4) Tomato Fusarium wilt

[0139] Wild-type strain WT of *Fusarium oxysporum* was activated on plates for 4 days. Mycelial cakes were then collected from the edges of individual colonies and cultured in PDB liquid medium with shaking for approximately 20 hours. Conidia were collected using a hemocytometer. The spore concentration of *Fusarium oxysporum* was diluted to 1 × 10⁻⁶. 7 The pathogenicity test for *Fusarium oxysporum* was conducted using the root-dipping method. Tomato seedlings with four new leaves and uniform growth were selected. Soil was removed from the roots, and the roots were rinsed thoroughly with water. The root tips were then cut off to create wounds that facilitate fungal infection. Ten tomato seedlings with uniform growth were selected as a group, and their roots were immersed in a 1:1 solution of water and... Fol (WT), volume ratio 1:1 (JDB15+) Fol Tomato seedlings were soaked in three combinations: WT+JDB15, double-distilled water (ddH2O), and 1400 ml of nutrient soil. After soaking for 30 minutes in each combination, the seedlings were removed and replanted in small pots filled with nutrient soil. The seedlings were then placed in an artificial climate chamber for cultivation. Disease incidence was recorded, photographs were taken, and the disease index of the tomato seedlings was calculated. The results are as follows: Figure 20Adding fermentation broth of strain JDB15 significantly reduced the disease index of tomato wilt compared to the WT group. Furthermore, with prolonged experimental time, the disease index in the JDB15 fermentation broth group did not significantly increase, while it significantly increased in the WT group. The reduction in the disease index in the JDB15 fermentation broth group was even more significant. This indicates that strain JDB15 has a significant inhibitory effect on tomato wilt, and this inhibitory effect becomes more pronounced with prolonged exposure to time.

[0140] (5) Gray mold

[0141] On a clean bench, after sterilizing the inoculation needle with an alcohol lamp and allowing it to cool, inoculate the gray mold pathogen onto a PDA plate and incubate in the dark at 20°C for 3-4 days for activation. 12 hours prior to incubation, prepare water and fermentation broth for strain JDB15, respectively, and spray them evenly onto the surface of detached tobacco leaves. On the clean bench, sterilize the punch with an alcohol lamp and, after cooling, collect mycelial cakes from the edge of the colony. Take leaves that have been pre-sprayed with water (WT) and fermentation broth for strain JDB15 (WT+JDB15), respectively, and inoculate the gray mold pathogen mycelial cakes onto fresh, healthy detached leaves. Place them in a plastic dish lined with moist absorbent paper, seal to retain moisture, and incubate at 20°C in the dark. Each strain treatment is replicated approximately 5 times. After 72 hours of incubation, measure the diameter of the lesion at each inoculation point using the cross-sectional method, and evaluate the pathogenicity of the strain based on the average diameter of each replicate. Figure 21 As shown, the diameter of gray mold lesions on tobacco leaves inoculated with strain JDB15 was significantly reduced, showing a significant difference from the control group (WT).

[0142] (6) Peach anthrax

[0143] Commercially ripe fruit (still firm, but with no green skin) is rinsed with detergent and water, surface-sterilized in 1% sodium hypochlorite for 2 minutes, then rinsed with sterile water and air-dried on sterile paper. The fruit is then punctured approximately 5 mm deep with a sterilized toothpick. The anthracnose spore suspension is washed away with a smear stick, adjusting the spore concentration to 1 × 10⁻⁶. 6 The conidial suspension was diluted to a concentration of 10 μL / ml and mixed separately with water (WT) and fermentation broth of strain JDB15 (WT+JDB15) at a volume ratio of 1:1. 10 μL of the resulting conidial suspension was then dropped onto each wound. 10 μL of sterile water (H2O) was added to the control fruit (CK) or leaf. Each fruit had two inoculation sites. Three fruits were inoculated for each treatment. The inoculated fruits were placed in plastic trays on 30 mm diameter plastic rings for stability. Moistened absorbent paper was placed at the bottom, and the top was sealed with plastic film to maintain humidity. The peach fruits were cultured at 25°C for 5 days. Pathogenicity was evaluated by lesion diameter. Lesion size was the average of two vertical diameters. Results are as follows: Figure 22The addition of the fermentation liquor of strain JDB15 significantly reduced the lesion diameter of peach anthracnose, and the difference was significant compared with the control group.

[0144] The above merely describes the preferred embodiments of the present application and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A banana endophytic Bacillus velezensis JDB15, characterized in that, Named as Bacillus velezensis It was deposited in Guangdong Microbial Culture Collection Center and the deposit number is GDMCC No: 66431.

2. The fermentation broth of the banana endophytic Bacillus velezensis JDB15 according to claim 1.

3. A formulation characterized in that, A preparation containing the banana endophytic Bacillus velezensis JDB15 according to claim 1 or the fermentation broth according to claim 2.

4. Use of the banana endophytic Bacillus velezensis JDB15 according to claim 1, or the fermentation broth according to claim 2, or the preparation according to claim 3 in the preparation of a preparation for antagonizing Fusarium oxysporum f. sp. cubense, Botrytis cinerea, Fusarium graminearum, Magnaporthe oryzae, Sclerotinia sclerotiorum, Rhizoctonia solani, Fusarium oxysporum f. sp. cucumerinum, Sclerotium rolfsii, Fusarium fujikuroi, Glomerella cingulata, Fusarium solani f. sp. glycines, Monilinia fructicola, Monilinia laxa, Fusarium oxysporum f. sp. lycopersici, Alternaria alternata, Bipolaris maydis, Xanthomonas campestris and Pseudomonas cichorii.

5. Use of the banana endophytic Bacillus velezensis JDB15 according to claim 1, or the fermentation broth according to claim 2, or the preparation according to claim 3 in the preparation of a preparation for controlling diseases caused by Fusarium oxysporum f. sp. cubense, Botrytis cinerea, Fusarium graminearum, Magnaporthe oryzae, Sclerotinia sclerotiorum, Rhizoctonia solani, Fusarium oxysporum f. sp. cucumerinum, Sclerotium rolfsii, Monilinia fructicola, Monilinia laxa, Fusarium oxysporum f. sp. lycopersici, Alternaria alternata, Bipolaris maydis, Xanthomonas campestris and / or Pseudomonas cichorii, or for controlling nematodes.

6. Use of the banana endophytic B. beckiana JDB15 according to claim 1, or of the fermentation broth according to claim 2, or of the preparation according to claim 3 for the preparation of a preparation for increasing the resistance of banana plants against Fusarium wilt of banana, characterized in that, The Bacillus velezensis JDB15, the fermentation broth or the preparation inhibits the hyphal growth of Fusarium oxysporum f. sp. cubense, inhibits the spore germination of Fusarium oxysporum f. sp. cubense and inhibits Fusarium oxysporum f. sp. cubense.

7. Use of the fermentation broth according to claim 2 in increasing the stem diameter, the plant height, the leaf area, the fresh weight of the plant, the dry weight of the plant and / or the number of roots of a banana plant.

8. Use of the fermentation broth according to claim 2 in increasing the peroxidase activity and / or the catalase content in a normal banana plant and in a banana plant infected with Fusarium oxysporum f. sp. cubense.

9. Use of the banana endophytic Bacillus velezensis JDB15 according to claim 1 in nitrogen fixation and / or potassium solubilization.

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