Acomonassp.kvbp1 strain and application thereof in preventing and treating kiwifruit canker

Abstract

The application provides a Pantoea agglomerans KVBP1 strain, which is classified and named as Pantoea agglomerans KVBP1, and is preserved in the China Center for Type Culture Collection with a preservation number of CCTCC NO: M 20252888. The application also provides application of the KVBP1 strain in prevention and treatment of kiwi fruit canker disease and a biocontrol agent for preventing and treating kiwi fruit canker disease. The application has the advantages that a strain with a significant prevention and treatment effect on kiwi fruit canker disease is screened from kiwi fruit plant tissues and rhizosphere soil, is identified as the Pantoea agglomerans KVBP1 through multi-gene sequence analysis, and is verified in function through physiological and biochemical determination and in-vitro and in-vivo prevention and treatment effect tests, thereby providing a new high-quality biocontrol strain resource and technical support for healthy and sustainable development of the kiwi fruit industry.

Description

Technical Field

[0001] This invention relates to the field of agricultural microbial biocontrol technology, and in particular to a Pantotheca acuminata strain KVBP1 and its application in the control of kiwifruit canker. Background Technology

[0002] Kiwifruit belongs to the Actinidiaceae family ( Actinidiaceae Actinidis genus ( Actinidia Kiwifruit (Lindl.) is a large, deciduous, woody vine with separate male and female plants. Its pulp is rich in nutrients such as vitamin C, amino acids, sugars, and volatile flavor compounds; its vitamin C content is 80 times that of apples, earning it the reputation of "King of Fruits." It is an important specialty economic fruit tree in my country. Today, the planting area and industry scale of kiwifruit continue to expand, occupying an important position in domestic and international markets, and has become a core pillar industry for rural revitalization and increasing farmers' income in many regions.

[0003] However, with the continuous expansion of kiwifruit planting area and the extension of planting years, pest and disease problems have become increasingly prominent, among which the kiwifruit disease caused by *Pseudomonas syringae* (a bacterium) is particularly problematic. Pseudomonas syringae pv . actinidiae , Psa Kiwifruit canker, caused by bacteria, is a devastating bacterial disease that hinders the healthy development of the kiwifruit industry. This disease frequently breaks out in major kiwifruit producing areas worldwide, characterized by rapid spread, insidious onset, and difficulty in control. It can infect multiple organs of the kiwifruit plant, including branches, leaves, and fruit, causing gumming, wilting, and in severe cases, the death of the entire plant. Field incidence rates can reach 30% to 80%, yield losses can exceed 50%, and it can even lead to large-scale orchard destruction, causing serious economic losses to the kiwifruit industry worldwide and negatively impacting the progress of rural revitalization plans in my country.

[0004] Currently, the control of kiwifruit canker still relies mainly on chemical agents. However, the long-term and excessive use of chemical pesticides not only leads to increased drug resistance in pathogens and a gradual decline in control effectiveness, but also causes a series of ecological and food safety problems such as soil pollution and excessive pesticide residues in fruits, which contradicts the concept of green agricultural development. Although agricultural control aligns with the requirements of green development, it has significant shortcomings: the core rain-sheltered greenhouse cultivation model requires high-quality geographical conditions and significant capital investment, making it difficult to popularize in scattered planting areas in mountainous regions, and overall control is slow to take effect; at the same time, the disease-resistant breeding cycle is lengthy, and no fully resistant germplasm materials have yet been discovered.

[0005] Biological control, with its outstanding advantages such as environmental friendliness, sustainability, and safety against natural enemies, has become the core development direction of green prevention and control systems for fruit tree diseases. Therefore, screening and developing environmentally friendly biocontrol agents for the control of kiwifruit canker has significant practical value and scientific significance. Summary of the Invention

[0006] The technical problem to be solved by this invention is to provide a Pantotheca acuminata strain KVBP1 and its application in the prevention and control of kiwifruit canker. This strain has significant efficacy against kiwifruit canker and good environmental compatibility, effectively achieving green and efficient prevention and control of kiwifruit canker, and providing new high-quality biocontrol strain resources and technical support for the healthy and sustainable development of the kiwifruit industry.

[0007] The present invention solves the above-mentioned technical problems by adopting the following technical solutions: A cluster of pantothecin KVBP1 strains, classified and named Pantoea agglomerans KVBP1 was deposited at the China Center for Type Culture Collection on December 15, 2025, and is viable. Accession number CCTCC NO: M20252888. Address: China Center for Type Culture Collection, Wuhan University, Bayi Road, Wuchang District, Wuhan, Hubei Province.

[0008] As one of the preferred embodiments of the present invention, the strain has the characteristics of phosphorus solubilization, nitrogen fixation, potassium solubilization, iron carrier production and secretion of auxin IAA, and has a good control effect on kiwifruit canker disease.

[0009] Application of the above-mentioned Pantotheca cum Caulis KVBP1 strain in the prevention and control of kiwifruit canker.

[0010] As one of the preferred embodiments of the present invention, the strain is prepared into a bacterial suspension and applied to kiwifruit plants to prevent the occurrence of kiwifruit canker disease.

[0011] As one of the preferred embodiments of the present invention, the strain is prepared into a bacterial suspension and applied to the site of kiwifruit canker disease for the treatment of kiwifruit canker disease.

[0012] A biocontrol agent for preventing and controlling kiwifruit canker contains the aforementioned Pantotheca agglutinosa KVBP1 strain as the active ingredient, and an agriculturally acceptable carrier or excipient.

[0013] As one of the preferred embodiments of the present invention, the dosage form of the biocontrol agent is a bacterial suspension, wettable powder, microcapsule, or granule.

[0014] The advantages of this invention compared to the prior art are: (1) This invention isolates and screens a strain of kiwifruit plant tissue and rhizosphere soil that has a significant control effect on kiwifruit canker disease. Multi-gene sequence analysis identifies it as *Pantotheca acuminata* (…). Pantoea agglomerans KVBP1 was developed, and its function was verified through physiological and biochemical assays and in vitro and in vivo efficacy tests, providing new high-quality biocontrol strain resources and technical support for the healthy and sustainable development of the kiwifruit industry. (2) The strain of the present invention has significant antagonistic activity against kiwifruit canker pathogen, and at the same time has multiple growth-promoting abilities such as phosphorus solubilization, nitrogen fixation, potassium solubilization, iron carrier production and secretion of auxin IAA. It can promote plant nutrient absorption and growth while controlling diseases, and achieve the dual effect of "disease prevention + growth promotion". (3) This invention uses microbial biological control methods, without using chemical pesticides, leaving no residues, not polluting the environment, and not easily causing pathogens to develop drug resistance. It can effectively solve the problems of increased drug resistance, agricultural product residues and ecological pollution caused by traditional chemical control, and meets the requirements of green agricultural development. (4) The strain cultivation and bacterial solution preparation method of the present invention is simple, mild and low cost, which is convenient for large-scale production and field application. It can make up for the problems of long agricultural prevention and control cycle and difficulty in disease-resistant breeding. It is of great significance to ensure the healthy and sustainable development of the kiwi fruit industry and help rural revitalization. Attached Figure Description

[0015] Figure 1 This is a colony morphology diagram of strain KVBP1 in Example 2; Figure 2 This is a graph showing the results of the physiological and biochemical characteristics determination of strain KVBP1 in Example 2; Figure 3 This is the KVBP1 strain phylogenetic tree constructed based on multiple gene sequences in Example 2; Figure 4 The fermentation filtrate of strain KVBP1 in Example 3 is effective against... Psa Growth inhibition curve (* indicates growth inhibition) P <0.05, ** indicates P <0.01, *** indicates P <0.001); Figure 5 The KVBP1 strain in Example 4 is effective against the kiwifruit canker pathogen. Psa Figures showing the in vitro control efficacy and significance analysis (Figure A shows the phenotypic pattern of kiwifruit leaf disc disease in different treatment groups; Figure B shows the bar chart of leaf disc lesion area statistics and significance analysis in different treatment groups). Figure 6 The graph shows the results of the control efficacy test of strain KVBP1 on kiwifruit branches in Example 4 (Figure A shows the disease phenotype of different treatment groups of detached branches; Figure B shows the disease phenotype of different treatment groups of live branches; Figure C shows the bar chart of the statistical significance analysis of lesion length in different treatment groups of detached branches; Figure D shows the bar chart of the statistical significance analysis of lesion length in different treatment groups of live branches). Detailed Implementation

[0016] The embodiments of the present invention are described in detail below. These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments.

[0017] The culture medium formulations involved in the following examples are as follows: KBA medium: 20.0 g peptone, 10.0 g glycerol, 1.5 g magnesium sulfate heptahydrate, 1.5 g dipotassium hydrogen phosphate, 15.0 g agar, add pure water to 1000 mL, pH 7.0; Monkina Organic Phosphorus Medium: 10.0 g glucose, 0.5 g ammonium sulfate, 0.3 g sodium chloride, 0.3 g magnesium sulfate heptahydrate, 0.03 g ferrous sulfate heptahydrate, 0.03 g manganese sulfate tetrahydrate, 0.2 g egg yolk lecithin, 5.0 g calcium phosphate, 15.0 g agar, add pure water to 1000 mL, pH 7.0; Potassium-solubilizing medium: sucrose 5.0 g, glucose 5.0 g, ammonium sulfate 0.5 g, yeast extract 0.5 g, magnesium sulfate 0.3 g, disodium hydrogen phosphate 2.0 g, ferrous sulfate 0.03 g, manganese sulfate 0.03 g, potassium feldspar 2.0 g, agar 15.0 g, add pure water to 1000 mL, pH 7.2 ± 0.2; Chromium azurite medium: Chromium azurite 0.065 g, cetyltrimethylammonium bromide 0.0729 g, ferric chloride hexahydrate 0.002645 g, sodium dihydrogen phosphate dihydrate 0.29525 g, disodium hydrogen phosphate dodecahydrate 1.2135 g, ammonium chloride 0.125 g, potassium dihydrogen phosphate 0.0375 g, sodium chloride 0.0625 g, agar 9.0 g, add pure water to 1000 mL, pH 6.8 ± 0.1; Ashube medium: 0.2 g potassium dihydrogen phosphate, 0.2 g magnesium sulfate, 0.2 g sodium chloride, 5.0 g calcium carbonate, 10.0 g mannitol, 0.1 g calcium sulfate, 15.0 g agar, add pure water to 1000 mL, pH 7.0 ± 0.1.

[0018] The strain information involved in the following examples is as follows: Kiwi fruit canker bacteria ( Pseudomonas syringae pv. actinidiae , Psa The culture conditions were as follows: inoculated into KBA medium and cultured at a constant temperature of 28°C; Pantothecinia clumps ( Pantoea agglomerans ), namely the KVBP1 strain obtained by screening in this invention (preservation number: CCTCC NO: M 20252888).

[0019] In addition, unless otherwise specified, all experimental operations in the following embodiments follow conventional techniques in the art; the reagents, materials, strains, etc. used are all commercially available products or can be obtained by the public through public channels.

[0020] Example 1: Screening and obtaining KVBP1 strain: 1. Isolation and purification of biocontrol strains Healthy, undamaged kiwifruit branches, leaves, and roots were selected for endophytic bacteria isolation. The collected branches, leaves, and roots underwent surface disinfection by rinsing with sterile water for 30 seconds, followed by immersion in 75% ethanol for 1 minute, then in 2% NaClO for 3 minutes. Finally, the plant tissue was washed three times consecutively with sterile water for 30 seconds each time. Simultaneously, the final wash water was plated using KBA and incubated at 28°C for 72 hours. The absence of any single colony growth indicated successful surface disinfection of the plant tissue.

[0021] Large soil particles attached to the roots were removed using a sterile soft brush. The plant roots were placed in a sterile tube, and 50 mL of PBS (pH = 7.4) buffer was added. The tube was vortexed for 1 min three times. The washed roots were then removed and placed in a sterile centrifuge tube containing 15 mL of PBS. The centrifuge tube was sonicated for 30 s × 3 times in PBS. The root samples were used as samples for endophytic bacteria detection and were sterilized. 1 g each of the surface-sterilized roots, branches, and leaves were cut with sterile scissors, added to 9 mL of sterile water, and thoroughly ground. After standing for 5 min, the mixture was serially diluted 10-fold to obtain different concentrations. 100 μL of the homogenate was pipetted onto a KBA plate and evenly spread on the surface of the culture medium. The experiment was repeated 3 times and incubated at 28°C for 12–72 h.

[0022] Representative single colonies were selected based on morphological characteristics, transferred to KBA plates, purified by streak plating in three zones, and the cultures were placed in 25% glycerol and stored at -80℃ for later use.

[0023] 2. Screening of biocontrol strains Take all the strains purified and preserved in the previous step for later use; at the same time, prepare the kiwifruit canker pathogen. Psa The bacterial suspension was prepared and bacterial plates were constructed, as follows: Kiwi fruit canker pathogens were inoculated. Psa The culture was inoculated into KBA liquid medium and cultured on a shaker at 28°C and 180 r / min for 48 h. The bacterial suspension was then centrifuged at 8000 r / min for 3 min to remove the supernatant. The suspension was resuspended in sterile water, and the concentration was adjusted to 10. 8 CFU / mL. Add 5 mL of KBA medium cooled to 50°C to 100 mL of KBA medium. Psa Mix the bacterial suspension thoroughly, pour into plates, and allow to solidify for later use. Simultaneously, prepare a solution free of... Psa KBA plates containing bacterial suspension were used as negative controls.

[0024] Screening was performed using the plate confrontation method: sterile toothpicks were used to pick up the prepared isolated strains and spot-inoculate them onto the surface of prepared plates. The inoculated plates were placed in an incubator at 28°C and inverted for 12–48 h. The diameter of the inhibition zone was measured using the cross-hatching method. Each experimental treatment was repeated three times.

[0025] Filter out the Psa Strains with antagonistic effects (i.e., the fermentation supernatant has antibacterial activity) were used as target strains in subsequent pathogenicity assays.

[0026] 3. Screening Results This study isolated a large number of bacteria from kiwifruit plant tissues, and after multiple rounds of screening, obtained a strain that was effective against... Psa The pantothecin strain with highly efficient antagonistic ability was named strain KVBP1.

[0027] Example 2: Identification of KVBP1 strain: 1. Bacterial morphology and physiological and biochemical tests (1) Select a single colony of strain KVBP1, streak it on KBA medium for purification, incubate at 28℃ for 2 days, and observe its colony morphology, color, edge characteristics and surface gloss.

[0028] Observation results as follows Figure 1 As shown: The colony morphology of strain KVBP1 is round, light yellow, smooth and moist, raised, and with clear edges.

[0029] (2) The physiological and biochemical characteristics of strain KVBP1 were determined, including its phosphorus solubilization, nitrogen fixation, potassium solubilization, and siderophore production capabilities. Among them, phosphorus solubilization capability: the activated KVBP1 strain was inoculated on Mongkina organic phosphorus medium and the presence of a clear zone was observed; nitrogen fixation capability: the strain was inoculated on Assumption nitrogen-free medium and the normal growth was observed; potassium solubilization capability: the strain was inoculated on potassium-solubilizing medium and the formation of a clear zone was observed; siderophore production capability: the strain was inoculated on Chromium azurite medium and the presence of a yellow-green halo was observed.

[0030] Simultaneously, the ability of the KVBP1 strain to secrete auxin (IAA) was determined: after activating the strain for 24 h, it was transferred to KBA liquid medium containing 200 mg / L tryptophan at a 1% inoculum and cultured at 28℃ and 180 r / min for 48 h with shaking; after the culture was completed, it was centrifuged at 10000 r / min for 10 min, and 2 mL of supernatant was mixed with 2 mL of Salkowski colorimetric solution. This was repeated 3 times, and the IAA content produced by the strain was determined by colorimetry.

[0031] The measurement results are as follows Figure 2 As shown: strain KVBP1 forms a yellow-green halo on chromic azure medium (side carrier production), a clear ring on Monkina organic phosphorus medium (phosphorus solubilization), grows normally on Assumption nitrogen-free medium (nitrogen fixation), forms a yellow halo on potassium-solubilizing medium (potassium solubilization), and shows a pink color in the Salkowski colorimetric reaction (IAA production); indicating that KVBP1 possesses multiple plant growth-promoting functions such as phosphorus solubilization, nitrogen fixation, potassium solubilization, side carrier production, and IAA production.

[0032] 2. Molecular biological identification Genomic DNA was extracted from strain KVBP1, and two housekeeping genes were selected. rpoB (SEQ ID NO.1) and leuS (SEQ ID NO.2) and 16S rRNA (SEQ ID NO.3) were used as the target genes for PCR amplification. The amplification products were detected by 1% agarose gel electrophoresis. The amplification products with bright, clear bands without impurities and the same length as the amplified gene fragment were selected and sent to the sequencing company (Shanghai Sangon Biotech Co., Ltd.) for sequencing.

[0033] The obtained sequences were analyzed and proofread using DNAMAN v. 9.0 software. The proofread sequences were then compared using BLAST in NCBI. The results showed that the three target gene sequences were respectively aligned with... Pantoea agglomerans The homology of (GenBank accession numbers OQ813505.1, OR881504.1, OP102615.1) is 99.89%, 99.43%, and 99.79%, respectively, all higher than 95%.

[0034] Multiple alignments of each gene sequence were performed using MEGA11 software. After removing redundant sequences at both ends, the sequences were analyzed according to 16S rRNA- leuS - rpoB Sequential assembly was performed; a phylogenetic tree was constructed using the maximum likelihood method, and the results were analyzed using the bootstrap method (1000 cycles). The results showed that strain KVBP1 was related to... P. agglomerans Reference strains clustered into the same branch ( Figure 3 ).

[0035] Example 3: Determination of the antibacterial activity of strain KVBP1: The KVBP1 strain was inoculated into KBA liquid medium and cultured at 28°C and 180 rpm for 48 h. The culture was then centrifuged at 12000 rpm for 10 min, and the supernatant was collected and filtered through a 0.22 μm filter to obtain a sterile supernatant. Psa Inoculate the culture into KBA liquid medium, shake and incubate for 24 h. After shaking, aspirate the culture, centrifuge, discard the supernatant, resuspend in sterile water, and measure the OD using a UV spectrophotometer.600 and adjust OD 600 The concentration was 0.5; KBA medium was added at a ratio of 40% and the mixture was inoculated. Psa Afterwards, the samples were shaken and cultured. At 8, 12, 16, 20, and 24 hours of shaking, samples were taken and analyzed using an ELISA reader for OD500. 600 Measurement.

[0036] The measurement results are as follows Figure 4 As shown: During the 8-24 h culture period, treatment with added fermentation filtrate... Psa Group OD 600 The value was consistently significantly lower than Psa The isolated culture group showed that this inhibitory effect remained stable throughout the entire process; indicating that the sterile fermentation filtrate of strain KVBP1 has an inhibitory effect on... Psa It has a significant inhibitory effect on growth.

[0037] Example 4: Verification of the control efficacy of KVBP1 strain: 1. Determination of the efficacy of detached leaves Collect kiwi leaves that are growing uniformly, first disinfect the surface (soak in 0.6% sodium hypochlorite solution for 10 minutes), then rinse three times with sterile water, and air dry on sterilized plastic wrap; use a 12 mm diameter punch to make leaf discs (be careful to avoid the leaf veins), and set aside.

[0038] The KVBP1 strain and *Actinidia kiwifruit* causal agent were inoculated separately onto KBA medium and incubated at 28°C for 24–48 h. After the colonies stabilized, the colonies of both strains were scraped into sterile water using sterile cotton swabs to prepare OD (Oxygen Demand) samples. 600 = 0.1% bacterial suspension, then add sterile water to bring the volume to 50 mL, dilute to 10. 6 CFU / mL.

[0039] Three treatment groups were set up, with 30 replicates in each group, and vacuum permeation treatment was performed on the spare impellers, as detailed below: KVBP1 prevention group: First, place the leaf disc in KVBP1 bacterial solution for vacuum permeation and incubate for 24 h, then place the leaf disc in... Psa Vacuum permeation is performed in the bacterial solution; KVBP1 treatment group: First, the leaf disc was placed in KVBP1 bacterial solution for vacuum permeation. After culturing for 24 h, the leaf disc was placed in sterile water for vacuum permeation. Positive control group ( Psa First place the leaf disc Psa The bacterial solution was subjected to vacuum permeation, and after 24 hours of cultivation, the leaf disc was placed in sterile water for vacuum permeation.

[0040] After vacuum permeation, the leaf discs were placed on sterile filter paper, excess bacterial solution was absorbed from the surface, and the leaf discs were placed on water agar plates with the underside of the leaves facing up. The plates were then placed in an artificial climate incubator for cultivation. After 5 days of continuous cultivation, the disease status of the leaf discs was observed and photographed to record the disease situation.

[0041] 2. Inoculation test of detached branches with injuries Healthy kiwifruit branches of the Hongyang variety were selected as experimental materials. Fresh kiwifruit branches were rinsed with sterile water for 30 seconds, soaked in 0.6% NaClO for 15 minutes, rinsed three times with sterile water, dried, and then sealed at both ends of the branches with paraffin wax.

[0042] Wounds were prepared by making incisions on the branches using a sterile scalpel, and 10 μL of bacterial suspension (OD) was dripped into the wounds. 600 = 0.3), set the following treatment, with 5-10 branches per treatment, and repeat 3 times: KVBP1 prevention group: First, add KVBP1 bacterial solution, place in an artificial climate chamber for 24 hours, and then add... Psa bacterial solution; Positive control group ( Psa ): Add dropwise first Psa After placing the bacterial solution in an artificial climate chamber for 24 hours, sterile water was added dropwise. Negative control group (H2O): only sterile water was added.

[0043] After inoculation, the cuttings were placed in an artificial climate incubator (photoperiod L / D: 16 h / 8 h; day / night temperature: 18℃ / 14℃; relative humidity 90%) for 20 days, and the results were recorded.

[0044] 3. Inoculation test of living branches with injuries Select healthy kiwifruit plants with good growth and uniform thickness. Prepare wounds by making incisions on the branches using a sterile scalpel, and apply 10 μL of bacterial solution to the wounds. Set up the following treatments, with 5-10 branches per treatment, repeated 3 times: KVBP1 treatment group: First drip infusion Psa Bacterial solution, KVBP1 bacterial solution added dropwise after 24 h; Cu(OH)2 reagent control group: first add dropwise Psa After 24 hours, 500 μg / mL Cu(OH)2 was added dropwise to the bacterial culture.

[0045] Positive control ( Psa First add sterile water, then add more after 24 hours. Psa Bacterial solution.

[0046] The inoculated plants were placed in a greenhouse and cultured for 14 days, and the results were recorded.

[0047] 3. Results of efficacy test Results of the control effect of detached blades are as follows Figure 5 As shown: In the kiwifruit detached leaf inoculation experiment, the positive control group (inoculated only with detached leaves) Psa Both leaves and leaf rosettes were severely affected, with the average lesion area in the detached leaf positive control group being 0.49 cm². 2 After preventative treatment with KVBP1 strain, the average lesion area on detached leaves in the preventative group was only 0.069 cm². 2 The average preventive effect reached 85.9%, and no obvious disease symptoms were observed in the leaf disc treatment group; these results fully demonstrate that strain KVBP1 can significantly inhibit the pathogen of kiwifruit canker. Psa It has an excellent preventive effect on the infection and spread of lesions in kiwifruit canker, and is safe and harmless to kiwifruit plants. It can be used as a potential biocontrol probiotic strain for the prevention and control of kiwifruit canker.

[0048] The control efficacy results of detached branches and living branches are as follows: Figure 6 As shown: In the kiwifruit detached branch inoculation experiment, 20 days after inoculation, the positive control (only...) Psa The average length of lesions on branches reached 14.3 mm, indicating severe disease; while branches treated with KVBP1 strain showed no obvious symptoms, indicating that KVBP1 strain has a significant preventive effect against kiwifruit canker; in the live branch inoculation experiment of kiwifruit, 14 days after inoculation, the average length of lesions on positive control branches was 8.7 mm; while the treatment group (first... Psa After treatment, the average length of KVBP1 lesions decreased to 4.0 mm, and the treatment effect reached 54.02%. There was no significant difference compared with the 500 μg / mL Cu(OH)2 treatment group, which proved that the KVBP1 strain has a good therapeutic effect on kiwifruit canker.

[0049] In summary, the *Pantothecinus* KVBP1 strain obtained in this invention exhibits significant antibacterial activity and stable control effect against *Actinidia kiwifruit* causal agent. This strain can effectively prevent disease occurrence on detached leaves and branches, and also exert a significant therapeutic effect on living branches. Furthermore, it possesses multiple plant growth-promoting characteristics such as phosphorus solubilization, nitrogen fixation, potassium solubilization, iron carrier production, and IAA production. It is safe and harmless to kiwifruit plants and can be used as a core strain to prepare biocontrol agents for the prevention and control of kiwifruit canker. It has good potential to be developed into a highly efficient and safe biocontrol agent for the prevention and control of kiwifruit canker, providing new strain resources and technical support for the green control of kiwifruit canker.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A clustered pantothecin KVBP1 strain, characterized in that, Classification name is Pantoea agglomerans KVBP1, deposited in China Center for Type Culture Collection, with the accession number CCTCC NO: M 20252888.

2. The strain of Pantoea vagans KVBP1 of claim 1, characterized in that, The strain possesses the characteristics of phosphorus solubilization, nitrogen fixation, potassium solubilization, iron carrier production, and secretion of auxin IAA, and has a significant preventive and control effect on kiwifruit canker.

3. The application of the Pantotheca acuminata KVBP1 strain as described in claim 1 or 2 in the prevention and control of kiwifruit canker.

4. Use according to claim 3, characterized in that, The strain was prepared into a bacterial suspension and applied to kiwifruit plants to prevent the occurrence of kiwifruit canker disease.

5. Use according to claim 3, characterized in that, The strain was prepared into a bacterial suspension and applied to the affected areas of kiwifruit ulcer disease for the treatment of kiwifruit ulcer disease.

6. A biocontrol agent for preventing and controlling kiwifruit canker, characterized in that, It contains the pantothecin KVBP1 strain as described in claim 1 or 2 as the active ingredient, and an agriculturally acceptable carrier or adjuvant.

7. The biocontrol agent according to claim 6, characterized in that, The biocontrol agent is available in the form of bacterial suspension, wettable powder, microcapsule, or granules.

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