Pseudomonas pyrrocinia for preventing and treating plant nematodes and use thereof

Abstract

The application discloses a kind of pyrrol burkholderia for preventing and treating plant nematode and application thereof.The pyrrol burkholderia BX1 is preserved in Guangdong Microbial Culture Collection Center on April 22, 2025, and the preservation number is GDMCC NO.66191.The bacteria have excellent lethal effect on plant nematodes represented by Meloidogyne exigua, Pratylenchus pratensis, Meloidogyne incognita, Bursaphelenchus xylophilus and strawberry nematode, have good control effect on plant nematode disease, are new broad-spectrum microbial nematocide selection;And the bacteria also have the effect of promoting plant growth, and can be developed into microbial inoculant and applied to agriculture.The application further optimizes the best fermentation condition of pyrrol burkholderia BX1, guarantees the nematode-killing activity of fermentation liquor and fermentation product and the control effect on nematode disease, lays a solid foundation for the production of related nematocide and bacterial fertilizer, and has very important significance for developing nematode-killing microbial source pesticide or pharmaceutical fertilizer.

Description

Technical Field

[0001] This invention belongs to the field of agricultural biocontrol technology. More specifically, it relates to Burkholderia pyrrole, a bacterium for controlling plant nematodes, and its application. Background Technology

[0002] Agriculture is a crucial foundation for human development. Plant nematode diseases are plant diseases caused by the invasion and parasitism of plant nematodes. Affected plants can suffer from impaired growth and development due to the nematodes absorbing nutrients from their bodies; the secretions produced during the nematode's metabolism can also irritate the host plant's cells and tissues, leading to plant deformities, reduced yields, and decreased quality of agricultural products. Seriously damaging plant nematodes in China include root-knot nematodes and pine wood nematodes.

[0003] Root-knot nematodes (Meloidogyne spp.) are highly specialized omnivorous plant pathogenic nematodes belonging to the genus *Meloidogyne* in the family Rhizoctoniaceae, superfamily Rhizoctoniaceae, order Rhizoctonia. Root-knot nematode disease, caused by these nematodes, has become one of the most important diseases affecting crops. They have a wide host range, infecting over 5,500 plant species, including numerous agricultural and economic crops such as rice, peanuts, and soybeans, as well as over 30 major vegetables such as solanaceous vegetables, legumes, radishes, carrots, lettuce, and cabbage, and major fruits such as melons, grapes, citrus fruits, bananas, and dragon fruit. Root-knot nematodes are very small, difficult to see with the naked eye, and can survive for up to a year without a host, making them difficult to control. They are one of the most important plant pathogenic nematodes, causing agricultural losses of up to $70 billion annually and reducing crop yields by more than 30%. Among them, the most widespread and economically damaging are the bean root-knot nematode (Meloidogyne enterolobii), the grass-like root-knot nematode (Meloidogyne graminicola), and the southern root-knot nematode (Meloidogyne incognita). For example, the bean root-knot nematode is widely distributed globally and can parasitize a variety of plants, including ornamental plants, economic crops, wild plants, and weeds. After infecting plants, it affects crop yield and quality, and in severe cases, causes crops to wither and die, resulting in serious economic losses.

[0004] The pine wilt nematode (Bursaphelenchus xylophilus) is a devastating forest disease that causes the death of large numbers of pine trees. Often referred to as the "cancer of pine trees," it is a major invasive alien species in China, characterized by multiple transmission routes, hidden infection sites, rapid onset, long incubation period, and difficulty in control. Since its discovery in 1982, it has caused serious damage to China's pine forest resources, natural landscapes, and ecological environment, resulting in severe economic and ecological losses. It has been listed as a quarantine pest for forest plants both domestically and internationally in China.

[0005] Currently, commonly used nematicides are mainly chemical agents such as abamectin and thiazophos. However, due to the increasing environmental pollution, population growth, and frequent food safety issues, agricultural production faces numerous challenges. Green agriculture and sustainable development have become the themes of agricultural production transformation. While using traditional chemical pesticides and fertilizers to control pests and diseases and increase crop yields can increase grain production to a certain extent, the misuse and abuse of chemical pesticides not only cause agricultural product quality and safety problems but also pose serious risks to human health and the ecological environment, such as harming human health, water and soil pollution, destroying biodiversity, and inducing pesticide resistance in pests.

[0006] Therefore, finding an efficient, green, and safe alternative to pesticide nematicides is an urgent priority for agricultural production. Summary of the Invention

[0007] This invention aims to explore superior microbial strains with broad-spectrum activity against plant nematodes, providing new microbial strains for green and safe nematicides. Research using Burkholderia BX1 in this invention shows that this bacterium has strong lethal toxic activity against the second-instar larvae of various common plant nematodes, such as root-knot nematodes and pine wood nematodes, and also promotes growth in plants such as peppers and tomatoes. These results are of great significance for enriching the resources of biocontrol bacteria for plant nematodes and for developing nematicidal microbial pesticides or fertilizers.

[0008] The purpose of this invention is to provide a strain of Burkholderia pyrrocinia BX1 and its inoculum.

[0009] Another object of the present invention is to provide the fermentation product of the aforementioned Burkholderia pyrrole BX1.

[0010] Another object of the present invention is to provide the application of Burkholderia pyrrologensis BX1 and its fermentation products in the control of plant nematodes and related diseases.

[0011] Another object of the present invention is to provide a nematicide or microbial fertilizer containing Burkholderia pyrrole-Holder BX1 and / or its fermentation products.

[0012] Another objective of this invention is to provide a method for controlling plant nematodes.

[0013] The above-mentioned objective of this invention is achieved through the following technical solution:

[0014] This invention has been developed through extensive research.

[0015] Therefore, the present invention claims protection for the following solution:

[0016] This invention provides a strain of Burkholderia pyrrocinia BX1, which was deposited at the Guangdong Provincial Center for Microbial Culture Collection on April 22, 2025, with accession number GDMCC NO.66191.

[0017] The present invention also provides an inoculum containing the aforementioned Burkholderia pyrrole BX1 and / or its fermentation broth.

[0018] The fermentation broth is obtained by culturing and fermenting the strain.

[0019] The microbial agent may also contain a culture medium and / or a carrier.

[0020] The present invention also provides the fermentation product of Burkholderia BX1.

[0021] The fermentation product refers to the product obtained by removing the bacterial cells from the fermentation broth (such as the filtrate obtained by filtering the fermentation broth to remove the bacterial cells).

[0022] The fermentation products can be further processed into different formulations. Such further processing can be carried out in a manner permitted in the art; for example, drying into a powder formulation, or mixing with pesticide or fertilizer-acceptable excipients, etc.

[0023] The present invention also provides the use of the above-mentioned Burkholderia pyrrole BX1 or its inoculum or fermentation product in killing plant nematodes and / or promoting plant growth.

[0024] The present invention also provides the application of the above-mentioned Burkholderia pyrrole BX1 or its inoculum or fermentation product in the control of plant nematodes and / or the control of plant diseases caused by plant nematodes.

[0025] The present invention also provides the use of the above-mentioned Burkholderia pyrrole BX1 or its inoculum or fermentation product in the preparation of nematicides or microbial fertilizers that kill plant nematodes and / or promote plant growth.

[0026] The present invention also provides a nematicide containing the aforementioned Burkholderia pyrrole BX1 and / or its fermentation broth, or its fermentation product.

[0027] The present invention also provides a fertilizer containing the aforementioned Burkholderia pyrrole BX1 and / or its fermentation broth, or its fermentation product.

[0028] The nematicide or fertilizer may also contain pesticide or fertilizer-acceptable adjuvants.

[0029] The *Burkholderia pyrrole* BX1 and related products provided by this invention have excellent lethal effects on plant nematodes, including *Eriocheir sinensis*, *Poaceae* root-knot nematode, *Southern root-knot nematode*, *Pine wood nematode*, and *Strombus scabra*. They have good control effects on plant nematode diseases and also promote plant growth, making them an excellent strain for green control of plant nematodes.

[0030] Based on this, the present invention also provides a method for killing plant nematodes or preventing plant nematode diseases, which involves applying to plants a microbial agent, nematicide, or fertilizer containing Burkholderia pyrroloides BX1 or its fermentation broth or fermentation products.

[0031] In terms of the scope of application, the plant nematodes include one or more of the following: root-knot nematodes, pine wood nematodes, and smooth blade nematodes.

[0032] Furthermore, the root-knot nematodes include *Eriocheir sinensis* root-knot nematode, *Poaceae* root-knot nematode, *Southern root-knot nematode*, etc.

[0033] The nematode includes the strawberry nematode.

[0034] The present invention further optimizes the optimal fermentation conditions for Burkholderia pyrroloides BX1, that is, provides a preferred method for preparing the fermentation broth or fermentation product of Burkholderia pyrroloides BX1.

[0035] As one of the preferred embodiments, the fermentation broth is prepared by inoculating Burkholderia pyrrole BX1 strain into a culture medium and culturing it at 25-30℃ and 150-300r / min.

[0036] Preferably, the fermentation time is 12-48 hours. More preferably, the fermentation time is 18-42 hours. Even more preferably, the fermentation time is 30-36 hours. The optimal fermentation time is 36 hours.

[0037] Preferably, the fermentation temperature is 25-34℃. More preferably, the fermentation temperature is 28-31℃. The optimal fermentation temperature is 28℃.

[0038] Preferably, the fermentation speed is 150-300 r / min. More preferably, the fermentation speed is 160-240 r / min. Even more preferably, the fermentation speed is 200-240 r / min. Even more preferably, the fermentation speed is 200-220 r / min. The optimal fermentation speed is 220 r / min.

[0039] Preferably, the culture medium can be NB medium. The formula is: beef extract 1-5 g / mL, peptone 5-20 g / mL, NaCl 4-6 g / mL, balance water, pH 7-8.

[0040] Preferably, the culture medium can also be NA medium. The formula is: beef extract 1-5 g / L, peptone 5-20 g / L, NaCl 0.5-10 g / L, agar 10-20 g / L, balance water, pH 7-8.

[0041] In NB or NA medium, more preferably, beef extract 1-5 g / L and peptone 10-20 g / L.

[0042] Alternatively, in NB or NA medium, more preferably, 4-5 g / L of beef extract and 5-20 g / L of peptone.

[0043] Alternatively, in NB or NA medium, more preferably, 2-5 g / L of beef extract and 10-20 g / L of peptone.

[0044] Most preferably, the beef extract is 2 g / L and the peptone is 20 g / L in NB medium or NA medium.

[0045] In addition, the initial pH of the culture medium is 7.0-8.0. More preferably, the initial pH of the culture medium is 7.0-8.0. The optimal initial pH of the culture medium is 8.0.

[0046] Preferably, the fermentation broth is prepared by the following method: first, Burkholderia pyrroloides BX1 strain is inoculated into a seed culture medium and cultured at 25-30℃ and 150-300 r / min for 12-24 h; then, the resulting seed culture is inoculated into a fermentation culture medium and cultured at 25-30℃ and 150-300 r / min for 24-48 h to obtain the fermentation broth.

[0047] The seed culture medium formula is: 3g / mL beef extract, 10g / mL peptone, 5g / mL NaCl, pH 7.2.

[0048] The fermentation medium formula is as follows: 2 g / mL beef extract, 20 g / mL peptone, 5 g / mL NaCl, pH 8.0.

[0049] As a specific optional implementation, the fermentation broth is prepared by the following method: the *Burkholderia pyrrologensis* BX1 strain is inoculated into a seed culture medium (3 g / mL beef extract, 10 g / mL peptone, 5 g / mL NaCl, pH 7.2) at a volume ratio of 2%, and cultured at 28°C and 200 r / min for 12 h to obtain a seed liquid; then the seed liquid is inoculated into a fermentation culture medium (2 g / mL beef extract, 20 g / mL peptone, 5 g / mL NaCl, pH 8.0) at a volume ratio of 2%, and cultured at 28°C and 220 r / min for 36 h to obtain the final product.

[0050] As one of the preferred embodiments, the fermentation product is the filtrate of the fermentation broth, which is obtained by centrifuging the fermentation broth and then filtering the supernatant obtained by centrifugation.

[0051] The centrifugation conditions can be selected as 0-10℃, 5000-20000r / min for 5-30min.

[0052] The preferred centrifugation conditions are 4°C, 9000 r / min, and centrifugation for 10 min.

[0053] The filtration can be performed using a 0.22μm filter.

[0054] The present invention has the following beneficial effects:

[0055] This invention provides a *Burkholderia pyrrocinia* BX1 strain, deposited on April 22, 2025, at the Guangdong Provincial Microbial Culture Collection Center (GDMCC NO. 66191). Tests against various representative plant nematodes (including common and damaging nematodes such as the bean weevil, *Poaceae* root-knot nematode, southern root-knot nematode, pine wood nematode, and strawberry smooth blade nematode) demonstrate that this bacterium exhibits excellent lethality against plant nematodes and provides good control over plant nematode diseases, making it a promising new broad-spectrum nematicide. This invention provides a biological control strain for plant nematode control and can be developed into a microbial agent, providing technical support for the green control of plant nematodes.

[0056] This invention further optimizes the optimal fermentation conditions for Burkholderia pyrrole BX1, ensuring the nematicidal activity of its fermentation broth and fermentation products and its control effect on nematode diseases, laying a solid foundation for the production of related nematicides and microbial fertilizers.

[0057] This invention also tested the effects of Burkholderia pyrrole BX1 on the growth of peppers and tomatoes, indicating that the bacterium also has the effect of promoting plant growth. In addition, a considerable number of the currently identified species in the Burkholderia genus, to which this bacterium belongs, have been used as biological pesticides in plant disease control applications, demonstrating high safety for plants. Attached Figure Description

[0058] Figure 1 The image shows the morphological characteristics of strain BX1; a in the figure is Gram staining of strain BX1, and b is the colony of strain BX1 on beef extract peptone solid medium.

[0059] Figure 2This is an agarose gel electrophoresis image of the amplified 16S rRNA and recA gene fragments of strain BX1; in the figure, M is DNAMarker DS2000, lane 1 is the negative control for amplifying 16S rRNA using water as a template, lanes 2 and 3 are for amplifying 16S rRNA using strain BX1 as a template, lane 4 is the negative control for amplifying recA using water as a template, and lanes 5 and 6 are for amplifying recA using strain BX1 as a template.

[0060] Figure 3 The figure shows a phylogenetic tree of strain BX1 constructed based on the 16S rRNA and recA gene sequences; in the figure, a represents the sequence based on the 16S rRNA sequence, and b represents the sequence based on the recA gene sequence.

[0061] Figure 4 The fermentation filtrate of strain BX1 has a lethal effect on *Auricularia auricula-judae* root-knot nematode; in the figure, aa is the morphological image of nematodes after treatment with the control group culture medium, and b is the morphological image of nematodes after treatment with the fermentation filtrate of strain BX1.

[0062] Figure 5 The nematicidal activity of fermentation filtrate of strain BX1 against root-knot nematodes of *Anoectochilus edulis* was analyzed at different culture times. In the figure, a represents the 24-hour corrected mortality rate, and b represents the 48-hour corrected mortality rate. The data in the figure are the mean and standard error of three replicates. Different letters indicate that the mean values ​​were significantly different after analysis using Duncan's new multiple range test (P < 0.05).

[0063] Figure 6 The nematicidal activity of fermentation filtrate of strain BX1 against root-knot nematodes of *Auricularia auricula-judae* was analyzed at different culture temperatures. In the figure, a represents the 24-hour corrected mortality rate, and b represents the 48-hour corrected mortality rate. The data in the figure are the mean and standard error of three replicates. Different letters indicate that the mean values ​​showed significant differences after analysis using Duncan's new multiple range test (P < 0.05).

[0064] Figure 7 The nematicidal activity of fermentation filtrate of strain BX1 against root-knot nematodes of *Anoectochilus edulis* was analyzed at different fermentation speeds. In the figure, 'a' represents the 24-hour corrected mortality rate, and 'b' represents the 48-hour corrected mortality rate. The data in the figure are the mean and standard error of three replicates. Different letters indicate significant differences in the mean after analysis using Duncan's new multiple range test (P < 0.05).

[0065] Figure 8The nematicidal activity of fermentation filtrate of strain BX1 against root-knot nematodes of *Anoectochilus edulis* was analyzed under different initial pH values. In the figure, a represents the 24-hour corrected mortality rate, and b represents the 48-hour corrected mortality rate. The data in the figure are the mean and standard error of three replicates. Different letters indicate that the mean values ​​showed significant differences after analysis using Duncan's new multiple range test (P < 0.05).

[0066] Figure 9 The nematicidal activity of fermentation filtrate of strain BX1 against root-knot nematodes of *Anoectochilus edulis* was analyzed at different inoculation amounts. In the figure, a represents the 24-hour corrected mortality rate, and b represents the 48-hour corrected mortality rate. The data in the figure are the mean and standard error of three replicates. Different letters indicate that the mean values ​​showed significant differences after analysis using Duncan's new multiple range test (P < 0.05).

[0067] Figure 10 To analyze the nematicidal activity of fermentation filtrate of strain BX1 against root-knot nematodes of *Anoectochilus edulis* under different levels of beef extract and peptone combined culture medium; in the figure, a represents the 24-hour corrected mortality rate, and b represents the 48-hour corrected mortality rate; in the figure, B1P5 on the horizontal axis represents the addition of 1g beef extract and 5g peptone to 1L of culture medium, where B1 indicates a beef extract content of 1g / L, P5 indicates a peptone content of 5g / L, and so on; the data in the figure are the mean and standard error of three replicates, and different letters indicate that the mean was significantly different after analysis using Duncan's new multiple range test (P<0.05).

[0068] Figure 11 The nematicidal activity of fermentation filtrate of strain BX1 against root-knot nematodes of *Anoplophora chinensis* was analyzed under different loading levels. In the figure, 'a' represents the 24-hour corrected mortality rate, and 'b' represents the 48-hour corrected mortality rate. The data in the figure are the mean and standard error of three replicates. Different letters indicate significant differences in the mean after analysis using Duncan's new multiple range test (P < 0.05).

[0069] Figure 12 This study aims to statistically analyze the number of root knots and nematodes in pepper roots treated with the fermentation broth and filtrate of strain BX1 obtained under optimal fermentation conditions. In the figure, 'a' represents the number of root knots, and 'b' represents the number of nematodes. The data in the figure are the mean and standard error of 8 replicates. Different letters indicate that the mean values ​​showed significant differences after analysis using Duncan's new multiple range test (P<0.05).

[0070] Figure 13The figures show the root conditions of peppers inoculated with *Heliotropium indicum* after different treatments; in the figures, a represents the water treatment, b represents the fermentation broth treatment with strain BX1 obtained under optimal fermentation conditions, c represents the fermentation filtrate treatment with strain BX1 obtained under optimal fermentation conditions, and d represents the thiazophosphine treatment; the scale bar is 2 cm.

[0071] Figure 14 This study aims to statistically analyze the number of root knots and nematodes in tomato roots treated with the fermentation broth and filtrate of strain BX1 obtained under optimal fermentation conditions. In the figure, 'a' represents the number of root knots, and 'b' represents the number of nematodes. The data in the figure are the mean and standard error of 8 replicates. Different letters indicate that the mean values ​​showed significant differences after analysis using Duncan's new multiple range test (P<0.05).

[0072] Figure 15 The images show the root condition of tomatoes inoculated with *Eriocheir sinensis* after different treatments; in the figure, a represents the water treatment, b represents the fermentation broth treatment with strain BX1 obtained under optimal fermentation conditions, c represents the fermentation filtrate treatment with strain BX1 obtained under optimal fermentation conditions, and d represents the thiazophosphine treatment; the scale bar is 5 cm.

[0073] Figure 16 The fermentation broth of strain BX1 obtained under optimal fermentation conditions promotes the growth of chili peppers; Figure a is the control group: treated with NB culture medium; Figure b and c are the experimental groups: treated with fermentation broth of strain BX1 with OD600 of 1.0 and fermentation broth of strain BX1 with OD600 of 3.0, respectively; Scale bar is 5cm.

[0074] Figure 17 The effects of fermentation broth from strain BX1 obtained under optimal fermentation conditions on various growth indicators of chili peppers are shown in the figure. In the figure, a represents chili pepper root weight, b represents chili pepper root length, c represents chili pepper aboveground fresh weight, d represents chili pepper plant height, e represents the maximum leaf length, and f represents the maximum leaf width. The control group in the figure is treated with NB culture medium. Treatment groups 1 and 2 represent OD values ​​of [missing data - likely related to growth indicators]. 600 Fermentation broth of strain BX1 with an OD of 1.0 600 The fermentation broth of strain BX1 was treated with 3.0. The data in the figure are the mean and standard error of 10 replicates. Different letters indicate that the mean was significantly different after analysis by Duncan's new multiple range test (P<0.05).

[0075] Figure 18 The figure shows the growth-promoting effect of the fermentation broth of strain BX1 obtained under optimal fermentation conditions on tomatoes; Figure a is the control group: treated with NB culture medium; Figure b and c are the experimental groups: treated with fermentation broth of strain BX1 with OD600 of 1.0 and fermentation broth of strain BX1 with OD600 of 3.0, respectively; the scale bar is 5 cm.

[0076] Figure 19 The effects of fermentation broth from strain BX1 obtained under optimal fermentation conditions on various growth indicators of tomatoes are shown in the figure. In the figure, a represents tomato root weight, b represents tomato root length, c represents tomato aboveground fresh weight, d represents tomato plant height, e represents the length of the longest tomato leaf, and f represents the width of the longest tomato leaf. The control group in the figure is treated with NB culture medium. Treatment groups 1 and 2 represent OD values ​​of [missing data - likely related to growth indicators]. 600 Fermentation broth of strain BX1 with an OD of 1.0 600 The fermentation broth of strain BX1 was treated with 3.0. The data in the figure are the mean and standard error of three replicates. Different letters indicate that the mean was significantly different after analysis by Duncan's new multiple range test (P<0.05).

[0077] Figure 20 The nematicidal activity of the fermentation filtrate of strain BX1 obtained under optimal fermentation conditions against *Anoplophora spp.* root-knot nematode, *Poaceae* root-knot nematode, *Strombus spp.* strawberry, *Pinus wiltii*, and *Sinus spp.* root-knot nematode was analyzed. In the figure, a represents the 24-hour corrected mortality rate, and b represents the 48-hour corrected mortality rate. The data in the figure are the mean and standard error of three replicates. Different letters represent the mean. After analysis using Duncan's new multiple range test (P < 0.05), there were significant differences. Detailed Implementation

[0078] The present invention will be further described below with reference to specific embodiments and accompanying drawings, but the embodiments do not limit the present invention in any way.

[0079] Unless otherwise specified, the reagents, methods and equipment used in this invention are conventional reagents, methods and equipment in this technical field.

[0080] Unless otherwise specified, all reagents and materials used in the following examples are commercially available.

[0081] The nematodes used in the following examples, namely Meloidogyne enterolobii, Meloidogyne graminicola, Meloidogyne incognita, Bursaphelenchus xylophilus, and Aphelenchoides fragariae, were collected, identified, and preserved by the Nematode Research Laboratory of South China Agricultural University.

[0082] Example 1: Isolation and Identification of Burkholderia pyrrole BX1

[0083] 1. Separation

[0084] Soil samples: Rhizosphere soil from healthy tobacco plants in Mashi Town, Shixing County, Shaoguan City, Guangdong Province.

[0085] Methods: Soil samples were added to sterile water at a concentration of 10 g / L and incubated at 180 rpm for 30 min to obtain a soil suspension. The supernatant was collected by centrifugation. The supernatant was plated onto NA plates and purified by stepwise streak plating to obtain single colonies. Round, light yellow, opaque, smooth, glossy single colonies with regular edges (recorded as strain BX1) were selected and inoculated into NB liquid medium. The culture was carried out at 28℃ and 180 rpm for 24 h. The purified single colony was then stored in glycerol at -80℃.

[0086] 2. Identification

[0087] (1) Morphological identification

[0088] Strawberry strain BX1 was streaked onto beef extract peptone agar (NA medium) and incubated upside down at 28°C for 48 hours. Colony shape, color, and edge morphology were photographed and recorded. Gram staining was performed on bacteria BX1 to observe their morphology.

[0089] Strain BX1 was Gram-negative, rod-shaped, with single-ended flagella, and a cell size of (2.23–4.38) μm × (0.78–1.48) μm, with an average length of 3.34 ± 0.514 μm. After culturing on NA agar plates for 48 h, strain BX1 formed colonies with a diameter of 1–2 mm. The colonies were round, pale yellow, opaque, smooth, glossy, with regular edges, and did not produce fluorescence. Figure 1 ).

[0090] (2) Identification of physiological and biochemical characteristics

[0091] The physiological and biochemical characteristics of strain BX1, including carbon source utilization, oxidase assay, and catalase assay, were determined according to Bergey's Manual of Systematics of Archaea and Bacteria and the methods described by Han Chao and Liu Aixin (2012), as follows:

[0092] (1) Carbon source utilization test: The utilization of glucose, maltose, L-arabinose, L-rhamnose and D-xylose by strain BX1 was determined. Glucose and other single carbon sources (concentration of 1%) were added to the basic solid culture medium. 5 μL of bacterial solution was inoculated in the center of the different carbon source culture media and incubated upside down in a 28℃ incubator for 2-3 days. The bacterial growth was recorded.

[0093] (2) Oxidase test: Moisten sterile filter paper with a 1% dimethyl-p-phenylenediamine aqueous solution (do not over-wet), and use an inoculation loop to pick up a single colony of BX1 and smear it onto the moistened filter paper. If the bacterial growth turns red, the test is positive; if it does not turn red, the test is negative.

[0094] (3) Catalase test: Pick a single colony of strain BX1 with an inoculation loop and smear it on a glass slide with 3% hydrogen peroxide. Observe whether bubbles are produced. If bubbles are produced, the test is positive; if no bubbles are produced, the test is negative.

[0095] (4) Citrate test: Pick a single colony of strain BX1 with an inoculation loop and place it into a 2 mL centrifuge tube containing citrate identification culture medium. Incubate at 28°C and 200 rpm for 2–3 days. Then add 2–3 drops of 0.04% phenol red solution to the centrifuge tube. If the culture medium turns red, the test is positive; if the solution does not turn red, the test is negative.

[0096] (5) Malonic acid utilization test: Pick a single colony of strain BX1 with an inoculation loop and place it into a 2 mL centrifuge tube containing malonic acid identification culture medium. Incubate at 28°C and 200 r / min for 2–3 days. If the culture medium changes from green to blue, the test is positive; if the culture medium does not change color, the test is negative.

[0097] (6) Nitrate reduction test: Pick a single colony of strain BX1 with an inoculation loop and put it into a 2mL centrifuge tube containing nitrate liquid culture medium. Incubate at 28℃ and shake at 200r / min for 2 days. Add Griess reagent A and B to the culture medium. If the culture medium turns pink, rose red, orange, or brown, it indicates that nitrite is present, indicating that the strain has the ability to produce nitrate reductase, and the test is positive. If there is no color change, add 1-2 drops of diphenylamine reagent. If the culture medium turns blue, it indicates that there is still nitrate in the culture medium but no nitrite, indicating that the strain does not have the ability to produce nitrate reductase, and the test is negative.

[0098] (7) Methyl red test: Pick a single colony of strain BX1 with an inoculation loop and place it into a 2 mL centrifuge tube containing methyl red culture medium. Incubate at 28°C with shaking at 200 rpm for 2–3 days. Then add a few drops of methyl red solution to the culture medium and observe whether the culture medium turns red. If the culture medium turns red, the result is positive; if it does not turn red, the result is negative.

[0099] (8) VP test: Pick a single colony of strain BX1 with an inoculation loop and place it into a 2 mL centrifuge tube containing methyl red culture medium. Incubate at 28°C with shaking at 200 rpm for 2–3 days. Then, take a small amount of culture medium and mix it with an equal volume of 40% NaOH. Next, add a small amount of creatine and shake vigorously. Observe the color of the solution after 15 minutes. If the culture medium turns red, the test is positive; if the culture medium does not turn red, the test is negative.

[0100] (9) H2S production test: Take 5 μL of bacterial culture and inoculate it in the center of a specific culture medium. Invert the medium and incubate at 28℃ for 2-3 days. Take a picture and observe whether the area around the colony turns black. If it turns black, hydrogen sulfide is produced, and the test is positive; if it does not turn black, no hydrogen sulfide is produced, and the test is negative.

[0101] (10) Amylase production capacity: Take 5 μL of bacterial culture and inoculate it in the center of a specific culture medium. Invert the medium and incubate at 28℃ for 2-3 days. Then add iodine solution to the culture dish to detect whether a clear zone is formed. If a clear zone appears, it indicates that the strain has the ability to decompose starch, and the test is positive; if no clear zone appears, the test is negative.

[0102] (11) Gelatin liquefaction test: Use an inoculation needle to pick up strain BX1 into a test tube containing gelatin culture medium, and incubate at 4℃ for different times (7d, 14d, 28d) to observe whether the gelatin liquefies. If the gelatin in the test tube is liquid, it indicates that the strain has the ability to liquefy gelatin, and the test is positive; if the gelatin is solid, it indicates that the strain does not have the ability to liquefy gelatin, and the test is negative.

[0103] (12) Growth ability at 42℃: Take 5 μL of bacterial solution and inoculate it in the center of NA medium, then invert the medium and incubate at 42℃ for 2-3 days. If the strain can grow, the test is positive; if the strain cannot grow, the test is negative.

[0104] The results showed that the physiological and biochemical characteristics of strain BX1 were consistent with those of Burkholderia pyrrole described in Bergey's Manual of Systematics of Archaea and Bacteria and the physiological and biochemical characteristics of Burkholderia pyrrole strain A12 reported by Han Chao and Liu Aixin (2012) (Table).

[0105] Table 1. Physiological and biochemical characteristics of strain BX1 compared with those of Burkholderia pyrrole reported in the literature.

[0106]

[0107]

[0108] Note: In the second and third columns of the table, "+" indicates a positive test result, and "-" indicates a negative test result. In the fourth column of the table, "+" indicates that more than 90% of the isolates are positive; "V" indicates that 10% to 90% of the strains are positive; "-" indicates that less than 10% of the strains are positive; and " / " indicates no result.

[0109] (3) Molecular biological identification

[0110] Strawberry strain BX1 was activated by streaking in beef extract peptone liquid medium (NA medium), and single colonies were picked.

[0111] PCR amplification was performed using the universal primer pair 27F (5'-AGAGTTTGATCCTGGCTCAG-3') / 1492R (5'-GGTTACCTTGTTACGACTT-3') for amplifying bacterial 16S rRNA, and the specific primer pair BCR1-F (5'-TGACCGCCGAGAAGAGCAA-3') / BCR1-R (5'-CTCTTCTTCGTCCATCGCCTC-3') for amplifying the Burkholderia recA gene. The amplification reaction system is shown in Table 2 and the reaction procedure is shown in Table 3.

[0112] The PCR products were detected by 1% agarose gel electrophoresis, and the target fragment was recovered using a DNA recovery kit from Beijing Tiangen Biotech Co., Ltd., and then sent to Guangzhou Tianyi Huiyuan Gene Co., Ltd. for sequencing.

[0113] The 16S rRNA and recA gene sequences obtained from sequencing were BLAST aligned in the GenBank database. Using MEGA 5.0 software, a Burkholderia phylogenetic tree was constructed based on the 16S rRNA and recA gene sequences using the Neighbor-Joining Tree (NJ) method.

[0114] Table 2. PCR amplification reaction system of 16S rRNA and recA gene of strain BX1

[0115]

[0116] Table 3 PCR amplification reaction procedure

[0117]

[0118] Using strain BX1 as a template, PCR amplification was performed using primers for amplifying the 16S rRNA and recA genes. The amplification products were approximately 1500 bp and 700 bp in size, respectively. Figure 2Further sequencing revealed that the 16S rRNA and recA genes of strain BX1 were 1494 bp and 704 bp in size, respectively. BLAST alignment of the sequenced data with the NCBI database showed that the 16S rRNA had the highest similarity (99.93%) to the 16S rRNA of *Burkholderia pyrrocinia* (accession number: CP150850); the recA had the highest similarity (99.43%) to the recA of *Burkholderia pyrrocinia* (accession number: CP150849). A phylogenetic tree was further constructed... Figure 3 Both phylogenetic trees showed that strain BX1 formed a monolineage with Burkholderia pyrrole.

[0119] In summary, based on the morphological, physiological and biochemical characteristics and molecular biological results, strain BX1 was identified as Burkholderia pyrrocinia and deposited on April 22, 2025, at the Guangdong Provincial Microbial Culture Collection Center (Address: 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou), with accession number GDMCC NO.66191.

[0120] Example 2: Lethal effect of Burkholderia pyrrole BX1 on plant nematodes

[0121] The lethality of Burkholderia pyrrolobii BX1 against plant nematodes was tested, using Meloidogyne enterolobii as a representative example.

[0122] 1. Testing Method

[0123] Add 900 μL of fermentation filtrate of strain BX1 or blank NB culture medium (as control CK) to 100 μL of *Ixodes stolonifera* root-knot nematode solution (approximately 60 nematodes), and soak at room temperature for 24 h and 48 h. The number of dead nematodes is then counted. A nematode is considered dead only when it is in a rigid state and completely inactive when punctured with a needle. The formulas for calculating nematode mortality rate and corrected mortality rate (Fang Zhongda, 1998) are as follows:

[0124] Mortality rate = (Number of dead nematodes / Total number of nematodes) × 100%

[0125] Corrected mortality rate = (treatment mortality rate - control mortality rate) / (1 - control mortality rate) × 100%

[0126] 2. Test results are as follows Figure 4

[0127] Figure 4The images show the lethal effect of the fermentation filtrate of strain BX1 on *Burkholderia pyrrole* root-knot nematode (a is the morphology of nematodes after treatment with the control culture medium, and b is the morphology of nematodes after treatment with the fermentation filtrate of strain BX1). This indicates that *Burkholderia pyrrole* BX1 has a strong lethal effect on plant nematodes, represented by *Burkholderia pyrrole* root-knot nematode.

[0128] Example 3: Optimization of optimal fermentation conditions for Burkholderia pyrrole BX1

[0129] Using *Burkholderia pyrophora* root-knot nematodes as the test organism, the 24-h and 48-h corrected mortality rates of *Burkholderia pyrophora* BX1 filtrate after treatment were used as indicators of the amount of nematicidal substances produced by BX1. A single-factor method was employed to optimize the optimal fermentation conditions for the production of nematicidal active substances by *Burkholderia pyrophora* BX1. 900 μL of fermentation filtrate was added to 100 μL of *Burkholderia pyrophora* root-knot nematode solution (approximately 60 nematodes). NB culture medium was used as the control (CK), and each treatment was repeated three times. The nematode mortality criterion was: the nematode was in a rigid state; if it did not move when poked with a needle, it was considered dead.

[0130] Mortality rate = (Number of dead nematodes / Total number of nematodes) × 100%

[0131] Corrected mortality rate = (treatment mortality rate - control mortality rate) / (1 - control mortality rate) × 100%

[0132] I. Preparation of *Burkholderia pyrrole* BX1 seed culture

[0133] The strain stored at -80℃ was activated, and a single colony of the activated strain was picked and placed in 20 mL of NB culture medium (3 g beef extract, 10 g peptone, 5 g NaCl, and sterile water to a final volume of 1 L, pH 7.2). The culture was then incubated at 28℃ and 200 r / min for 12 h to obtain the seed culture.

[0134] II. Optimization of fermentation conditions for Burkholderia pyrrole-Holder BX1

[0135] 1. Determining the optimal fermentation time

[0136] 2% seed culture was added to NB medium at pH 7.0 (50 mL in a 150 mL Erlenmeyer flask) and cultured with shaking at 28℃ and 200 rpm for 6 h, 12 h, 18 h, 24 h, 30 h, 36 h, and 42 h, respectively. Fermentation broth from each time point was collected, centrifuged, and filtered. The resulting filtrate was then used to treat *Ixodes macrocarpa* root-knot nematodes. The number of dead nematodes was counted, and the mortality rate and corrected mortality rate were calculated.

[0137] The results show ( Figure 5 The optimal fermentation time for Burkholderia pyrrole Halle BX1 is 36 hours.

[0138] 2. Determining the optimal fermentation temperature

[0139] 2% seed culture was added to NB medium (pH 7.0) at 25℃, 28℃, 31℃, 34℃, and 37℃ (50 mL in a 150 mL Erlenmeyer flask), and cultured at 200 rpm for 36 h with shaking. Fermentation broths from different temperatures were collected, centrifuged, and filtered. The resulting filtrate was then used to treat *Ipomoea aquatica* root-knot nematodes. The number of dead nematodes was counted, and the mortality rate and corrected mortality rate were calculated.

[0140] The results show ( Figure 6 The optimal fermentation temperature for Burkholderia pyrrole Haller BX1 is 28℃.

[0141] 3. Determination of the optimal fermentation speed

[0142] At 28℃, 2% seed culture was placed in NB medium (pH 7.0, 50 mL in a 150 mL Erlenmeyer flask) and cultured with shaking at speeds of 160 r / min, 180 r / min, 200 r / min, 220 r / min, and 240 r / min for 36 h. Fermentation broths at different speeds were collected, centrifuged, and filtered. The resulting filtrate was then used to treat *Ixodes spp.* root-knot nematodes. The number of dead nematodes was counted, and the mortality rate and corrected mortality rate were calculated.

[0143] The results show ( Figure 7 The optimal culture speed for Burkholderia pyrrole Haller BX1 is 220 r / min.

[0144] 4. Determination of the optimal initial pH value

[0145] After inoculating 2% seed culture with NB culture medium at initial pH values ​​of 5.0, 6.0, 7.0, 8.0, and 9.0, strain BX1 was cultured at 28℃ and 220 r / min for 36 h. Fermentation broths from different initial pH values ​​were collected, centrifuged, and filtered. The resulting filtrate was then used to treat *Ixodes macrocarpa* root-knot nematodes. The number of nematode deaths was counted, and the mortality rate and corrected mortality rate were calculated.

[0146] The results show ( Figure 8 The optimal initial pH for Burkholderia pyrrole-Holder BX1 culture medium is 8.0.

[0147] 5. Determining the optimal inoculation dosage

[0148] Seed culture of 1%, 2%, 3%, 4%, and 5% was inoculated with NB medium with an initial pH of 8.0, and strain BX1 was cultured at 28℃ and 220 r / min for 36 h. Fermentation broth with different inoculation amounts was collected, centrifuged, and filtered. The resulting fermentation filtrate was then used to treat *Ixodes macrocarpa* root-knot nematodes. The number of nematode deaths was counted, and the mortality rate and corrected mortality rate were calculated.

[0149] The results show ( Figure 9 The inoculum size of Burkholderia pyrrole-Holder BX1 medium did not differ significantly, so 2% was selected for subsequent experiments.

[0150] 6. Determining the optimal combination of beef extract and peptone

[0151] Let beef extract (abbreviated as B) be at 5 levels of 1 g / L, 2 g / L, 3 g / L, 4 g / L and 5 g / L, and peptone (abbreviated as P) be at 4 levels of 5 g / L, 10 g / L, 15 g / L and 20 g / L. These can be combined to form different NB medium formulations, abbreviated as BXPY. For example, B1P5 means that the content of beef extract is 1 g and the content of peptone is 5 g in 1 L of NB medium (the content of NaCl is fixed at 5 g / L under different mediums), and so on.

[0152] BX1 strain was cultured in NB culture medium with an initial pH of 8.0 at a concentration of 2% seed culture at 28℃ and a shaking speed of 220 r / min for 36 h. The fermentation broth was collected, centrifuged, and filtered. The resulting filtrate was then used to treat *Ixodes macrocarpa* root-knot nematodes. The number of dead nematodes was counted, and the mortality rate and corrected mortality rate were calculated.

[0153] The results show ( Figure 10 The optimal combination of beef extract (2 g / L) and peptone (20 g / L) for Burkholderia pyrrole-Holder BX1 medium is abbreviated as B2P20.

[0154] 7. Determining the optimal loading amount

[0155] Using NB culture medium with the optimal combination of B2P20 at an initial pH of 8.0, 25 mL, 50 mL, 75 mL, and 100 mL (150 mL Erlenmeyer flasks) were prepared, respectively. After inoculating with 2% seed culture, strain BX1 was cultured at 28℃ and 220 r / min for 36 h. The fermentation broth was collected, centrifuged, and filtered. The fermentation filtrate was then used to treat *Ixodes macrocarpa* root-knot nematodes. The number of nematode deaths was counted, and the mortality rate and corrected mortality rate were calculated.

[0156] The results show ( Figure 11 The loading of Burkholderia pyrrole-Holder BX1 medium did not differ significantly.

[0157] In summary, the optimal fermentation conditions for *Burkholderia pyroclasticis* BX1 were: 28°C, initial pH 8.0, NB broth (B2P20) containing 2 g / L beef extract and 20 g / L peptone, a fermentation speed of 220 rpm, a 2% inoculum size, a 50 mL (150 mL) Erlenmeyer flask loading, and a fermentation time of 36 h. Under these conditions, the fermentation filtrate of strain BX1 resulted in corrected mortality rates of 95.7% and 97.8% for *Euphorbia milii* root-knot nematodes after treatment for 24 h and 48 h, respectively.

[0158] The Burkholderia pyrrologensis BX1 fermentation broths in the following examples were all prepared using the optimal fermentation conditions described in this example.

[0159] Example 4: Pot experiment on the control of root-knot nematodes in peppers, tomatoes, and beans using Burkholderia pyrrole BX1 fermentation broth and its fermentation filtrate.

[0160] The root-knot nematode of the bean weevil can infect peppers and tomatoes, causing serious diseases. This example uses peppers and tomatoes as model crops in a pot experiment. The fermentation broth of *Burkholderia pyrroloides* BX1, prepared in Example 3, was used. When peppers and tomatoes (pot diameter 12.5 cm) had 4-5 true leaves, 800 second-instar larvae of the bean weevil were inoculated per plant. Ten hours after inoculation, 50 mL of the treatment solution was applied to each treatment group. Three treatment groups were set up, with water as a negative control. Treatment group 1 was treated with the fermentation broth of *Burkholderia pyrroloides* BX1, treatment group 2 was treated with the fermentation filtrate of *Burkholderia pyrroloides* BX1, and treatment group 3 was treated with thiazophos (Zonong, Dezhou Xianglong Biochemical Co., Ltd.; calculated at 750 mL / acre, 14 μL per pot) as a positive control. Eight plants were used in each treatment group. After 30 days of treatment, the number of root knots on plant roots and the number of root nematodes were counted, and the severity of root knots was graded (see table for grading). The root knot index and control effect were then calculated using the following formula. The disease index and control effect for each treatment were calculated; the significance of differences between treatments was analyzed using Duncan's multiple range test with SPSS software.

[0161]

[0162] Table 4 Grading Criteria for Root Knot Severity

[0163]

[0164] The results are as follows Figure 12 and Figure 14 As shown, after drenching the roots with fermentation broth and filtrate of strain BX1 for 30 days, the number of root knots and nematode numbers on pepper and tomato roots were significantly reduced compared to the control group. Figure 12It was found that, in chili peppers, the number of root knots and nematodes decreased by 79.1% and 73.1% respectively in the fermentation broth treatment group, by 76.2% in both the root knot and nematode numbers in the fermentation filtrate treatment group, and by 93.0% and 92.7% respectively in the thiazophos treatment group. Figure 14 It was found that in tomatoes, the number of root knots and nematodes decreased by 41.0% and 57.5% in the fermentation broth treatment group, respectively; the number of root knots and nematodes decreased by 31.7% and 50.6% in the fermentation filtrate treatment group, respectively; and the number of root knots and nematodes decreased by 90.5% and 93.6% in the thiazophos treatment group, respectively.

[0165] The severity of root knots was further graded, and the root knot index was calculated. The control effect was calculated using the rate of decrease in the root knot index (Table 5). Figure 13 and Figure 15 Table 5 shows that the fermentation broth and fermentation filtrate had control effects of 58.3% and 50.0% on root-knot nematode disease of pepper and tomato, respectively; and 41.7% and 37.5% on root-knot nematode disease of tomato, respectively. The results indicate that both the fermentation broth and fermentation filtrate of strain BX1 can control root-knot nematode disease in pepper and tomato.

[0166] Table 5. Disease index and control effect of fermentation broth and fermentation filtrate of strain BX1 on peppers and tomatoes.

[0167]

[0168] Example 5: Growth-promoting effect of Burkholderia pyrrole-Holder fermentation broth on peppers and tomatoes.

[0169] Healthy seedlings with two true leaves and uniform growth were selected and transplanted into disposable plastic cups containing 80g of seedling substrate, with one seedling per cup. The experiment included three treatment groups, using OD solutions of different concentrations. 600 =1.0 Burkholderia pyrrole BX1 fermentation broth, OD 600 =3.0 Burkholderia pyrrologensis BX1 fermentation broth and NB culture medium (control group) were used, with 10 plants replicated for each treatment in a completely randomized block design. Plants were cultured under natural light conditions, and 5 mL of the corresponding treatment solution was applied every 6 days. After 28 days of treatment, plant height, aboveground fresh weight, root length, root weight, and the length and width of the largest unfolded leaf were measured. The experiment was conducted in triplicate.

[0170] The effects of pyrrole Burkehold BX1 fermentation broth on pepper growth promotion are as follows: Figure 16 , 17 As shown, compared with watering NB culture medium, watering OD... 600 For 1.0 and OD 600The fermentation broth of strain BX1 (3.0) increased pepper root weight by 30.7% and 39.6%, root length by 12.9% and 13.9%, aboveground fresh weight by 20.9% and 31.6%, plant height by 8.7% and 13.0%, the length of the largest leaf by 9.7% and 24.0%, and the width of the largest leaf by 10.9% and 21.0%.

[0171] The effects of pyrrole Burkehold BX1 fermentation broth on tomato growth promotion are as follows: Figure 18 , 19 As shown, compared with watering NB culture medium, watering OD... 600 For 1.0 and OD 600 The fermentation broth of strain BX1 (concentration 3.0) increased tomato root weight by 18.8% and 40.2%, respectively; root length by 0.7% and 13.6%, respectively; aboveground fresh weight by 24.0% and 29.8%, respectively; plant height by 10.3% and 18.0%, respectively; the length of the largest leaf by 5.2% and 8.9%, respectively; and the width of the largest leaf by 10.9% and 12.7%, respectively. These results indicate that the fermentation broth of strain BX1 promotes the growth of both pepper and tomato plants, and this effect is more pronounced with increasing bacterial concentration.

[0172] Example 6: Nematicidal effect of Burkholderia pyrroloides BX1 fermentation filtrate on *Auricularia auricula-judae* root-knot nematode, *Poaceae* root-knot nematode, *Strombus scabra*, *Pinus wiltii*, and *Hemiberlesia sapiens*.

[0173] BX1 was cultured under the optimal fermentation conditions obtained in Example 3 to obtain fermentation filtrate. 900 μL of the fermentation filtrate was then mixed with 100 μL of a solution containing approximately 60 nematodes (including *Heliotropium indicum* root-knot nematodes, *Poaceae* root-knot nematodes, *Strombus sclerotium*, *Pinus fibrosum*, and *Heliotropium indicum* root-knot nematodes). NB culture medium was used as the control (CK). Each treatment was repeated three times. The criteria for nematode mortality and the calculation of mortality rates and corrected mortality rates were the same as in Example 3.

[0174] The results show ( Figure 20 The 24-hour corrected mortality rates of *Burkholderia pyrrole* BX1 fermentation filtrate against *Auricularia auricula-judae* root-knot nematode, *Poaceae* root-knot nematode, *Strombus scabra*, *Pinus wiltii*, and *Sinus spp.* root-knot nematode were 95.7%, 75.6%, 83.1%, 91.9%, and 93.8%, respectively, while the 48-hour corrected mortality rates were 97.8%, 94.1%, 95.1%, 96.2%, and 99.7%, respectively.

[0175] In summary, this invention optimized the fermentation conditions of strain BX1 using a single-factor method, thereby enhancing its nematicidal activity against *Burkholderia pyrophora* root-knot nematodes. Treatment of pepper and tomato plants with *Burkholderia pyrophora* root-knot nematode disease using the fermentation broth and filtrate of strain BX1 showed good results, and the fermentation broth of strain BX1 promoted the growth of peppers and tomatoes. Furthermore, the fermentation filtrate of strain BX1 exhibited a certain killing effect on *Poaceae* root-knot nematodes, strawberry *Scleroderma*, pine wood nematodes, and southern root-knot nematodes. Therefore, *Burkholderia pyrophora* strain BX1 is a multifunctional and highly efficient biocontrol bacterium with broad application prospects in controlling plant diseases caused by *Burkholderia pyrophora* root-knot nematodes.

[0176] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A strain of Burkholderia pyrrocinia BX1, characterized in that, This strain was deposited at the Guangdong Provincial Center for Microbial Culture Collection on April 22, 2025, with accession number GDMCCNO.66191.

2. A Burkholderia agent, characterized in that, Contains Burkholderia pyrrologensis BX1 as described in claim 1 and / or its fermentation broth.

3. A Burkholderia fermentation product, characterized in that, Fermentation products containing Burkholderia pyrrole BX1 as described in claim 1.

4. The use of Burkholderia pyrrologensis BX1 as described in claim 1, or the inoculum as described in claim 2, or the fermentation product as described in claim 3, in killing plant nematodes and / or promoting plant growth.

5. The use of Burkholderia pyrrologensis BX1 as described in claim 1, or the inoculum as described in claim 2, or the fermentation product as described in claim 3, in the control of plant nematodes and / or the control of plant diseases caused by plant nematodes.

6. The use of Burkholderia pyrrologensis BX1 of claim 1, the inoculum of claim 2, or the fermentation product of claim 3 in the preparation of nematicides or microbial fertilizers that kill plant nematodes and / or promote plant growth.

7. A nematicide, characterized in that, Contains Burkholderia pyrrologensis BX1 as described in claim 1 and / or its fermentation broth, or contains the fermentation product as described in claim 3.

8. A fertilizer, characterized in that, Contains Burkholderia pyrrologensis BX1 as described in claim 1 and / or its fermentation broth, or contains the fermentation product as described in claim 3.

9. The nematicide according to claim 7 or the fertilizer according to claim 8, characterized in that, It also contains pesticide or fertilizer-acceptable excipients.

10. A method for killing plant nematodes or controlling plant nematode diseases, characterized in that, Apply the fungicide of claim 2, the nematicide of claim 7, or the fertilizer of claim 8 to the plant.

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