Burkholderia pyrrocinia ZR-28 and application thereof

Abstract

The invention relates to the technical field of microorganisms, in particular to Burkholderia pyrrocinia ZR-28 and application of the Burkholderia pyrrocinia ZR-28, the Burkholderia pyrrocinia ZR-28 is preserved in China General Microbiological Culture Collection Center (CGMCC), the preservation address is No.3, Yard 1, West Beichen Road, Chaoyang District, Beijing, the preservation date is May 17, 2024, and the preservation number is CGMCC NO.30588. The invention further discloses a preparation method of the Burkholderia pyrrocinia ZR-28 and application of the Burkholderia pyrrocinia ZR-28. The Burkholderia pyrrocinia ZR-28 provided by the invention not only can promote the growth of plants such as strawberries and corns, but also has a biological control effect on agricultural diseases such as strawberry gray mold and corn southern leaf blight, has an excellent antagonistic effect on pathogenic bacteria of various plant diseases, and has wide application prospects and development space.

Description

Technical Field

[0001] The invention relates to the technical field of microorganisms, in particular to Burkholderia pyrroreus ZR-28 and application thereof. Background Art

[0002] Burkholderia pyrrocinia is a plant growth-promoting bacterium with good application prospects. It plays an important role in the growth and development of poplars and other plants. This strain has the advantages of disease resistance, growth promotion, and bioremediation, and is widely present in nature and is a dominant population in the environment. This strain can increase the activity of plant rhizosphere soil enzymes, enhance the plant's ability to absorb nutrients, and promote plant development. Studies have shown that Burkholderia pyrrocinia has a growth-promoting effect on different plants such as pear trees and poplars, and can increase growth indicators and the effective phosphorus content of rhizosphere soil. It also has the ability to efficiently solubilize phosphorus and produce siderophores, which can help plants overcome nutritional limitations and promote growth.

[0003] For example, studies have found that bacteria in the Burkholderia group of onions also have a variety of beneficial biological functions and can be used as biological control factors in agriculture and forestry. Studies have shown that some strains of the Burkholderia group of onions have significant control effects on crop rot and damping-off diseases. For example, Fan Qing et al. found that Burkholderia cepacia has a significant inhibitory effect on sweet cherry brown rot. In addition, Burkholderia pyrrole strains can also be used for biological control of nematode diseases. For example, the extracellular toxin produced by the B. cepacia H111 strain has strong insecticidal activity and can effectively kill Caenorhabditis elegans. In the biological control of plant diseases, Burkholderia pyrrole strains mainly play a biological control role through competition and antagonism.

[0004] However, although the prior art has reported that Burkholderia pyrrolate has a growth-promoting effect on different plants such as pear trees and poplars, and can increase growth indicators and the effective phosphorus content in rhizosphere soil, and has the ability to efficiently solubilize phosphorus and produce siderophores, which can help plants overcome nutritional limitations and promote growth, its growth-promoting mechanism is not clear and the growth-promoting effect is poor. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a Burkholderia pyrrolate ZR-28, so as to at least achieve the effect of growth promotion potential and fungal disease prevention and control.

[0006] The objective of the present invention is achieved through the following technical solutions:

[0007] On the one hand, the present application provides a Burkholderia pyrrocinia, named ZR-28, which is deposited in the General Microbiology Center of the China Microbiological Culture Collection Administration, with the deposit address at No. 3, Yard 1, Beichen Road West, Chaoyang District, Beijing, the deposit date is May 17, 2024, and the deposit number is CGMCC NO.30588.

[0008] The source of the Burkholderia pyrroreus ZR-28 is from the root, stem and leaf tissues of Taxus × media, separated and screened by the plate confrontation method. Sampling site: Emeishan Nature Reserve, Leshan City, Sichuan Province.

[0009] This application identified Burkholderia pyrroreus ZR-28 from the perspective of morphology and molecular biology:

[0010] Morphological identification: The colonies of Burkholderia pyrroreus ZR-28 are yellow and round, with a smooth and shiny surface, neat edges, and no fluorescence. Gram staining is red, and it is a Gram-negative bacterium.

[0011] Biomolecular identification: The fragment size of 16S rDNA of Burkholderia pyrrocinia ZR-28 is about 1800bp, and its homology with Burkholderia sp. is 100%. It is closely related to Burkholderia pyrrocinia (NR-116156.1), Burkholderia pyrrocinia (NR-112060.1) and Burkholderia pyrrocinia (NR-029210.1).

[0012] In one aspect, the present application provides the use of the above-mentioned Burkholderia pyrroreus ZR-28 in at least one of secreting siderophores and producing indoleacetic acid. :

[0013] On the one hand, the present application provides the application of the preparation containing the above-mentioned Burkholderia pyrroreus ZR-28 as an active ingredient in agriculture.

[0014] In one aspect, the present application provides a bacterial agent of the above-mentioned Burkholderia pyrroreus ZR-28.

[0015] On the one hand, the present application provides the use of the above-mentioned Burkholderia pyrroreus ZR-28 or the above-mentioned bacterial agent in promoting plant growth, characterized in that the plants include Rosaceae and Poaceae.

[0016] In some embodiments, the plants include Rosaceae and Poaceae.

[0017] On the one hand, the present application provides a medicine of the above-mentioned Burkholderia pyrroreus ZR-28 or the bacterial agent described in claim 4.

[0018] In some embodiments, the drug can be used for biological control of strawberry gray mold and corn leaf spot.

[0019] The beneficial effects of the present invention are:

[0020] 1) The Burkholderia pyrroreus ZR-28 provided in the present application has the ability to secrete iron carriers and IAA, which can not only improve the plant's absorption of elements such as iron, regulate plant growth and development, promote plant wound healing, but also improve the environment and reduce environmental pollution.

[0021] 2) The Burkholderia pyrrolate ZR-28 provided in the present application has an excellent growth-promoting effect on plants such as strawberry, corn and rice, and has a significant biological control effect on strawberry gray mold and corn leaf spot, and is a growth-promoting bacterium with strong application value.

[0022] 3) The antagonistic effect of Burkholderia pyrroreus ZR-28 provided in the present application on several common leaf disease pathogens such as B. cinerea, B. maydis, C. lunata, C. fructicola, P. theae, A. alternata, and C. boninense. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The morphological characteristics of Burkholderia pyrroreus ZR-28 are shown in Figure 1 (a. Colony plate growth diagram, scale bar is 1 cm; b. Single colony morphology diagram, scale bar is 100 μm; c. Gram staining diagram, scale bar is 10 μm; d. Scanning electron microscope diagram 3000x, scale bar is 500 nm);

[0024] Figure 2 This is the electrophoresis detection result of the PCR amplification product of Burkholderia pyrroreyi ZR-28 (lane M is 2000bpMaker);

[0025] Figure 3 This is the phylogenetic tree of the ZR-2816S rDNA gene of Burkholderia pyrroreus;

[0026] Figure 4 The growth diagram of Burkholderia pyrroreus ZR-28 on different culture media (a. PVK medium, b. calcium phytate medium, c. Ashby medium, d. CAS medium);

[0027] Figure 5The photos show the effect of Burkholderia pyrroreyi ZR-28 on the disease of detached strawberry leaves infected with Botrytis cinerea.

[0028] Figure 6 This is a statistical bar graph showing the effect of Burkholderia pyrroreyi ZR-28 treatment on the lesion area of ​​detached strawberry leaves infected with Botrytis cinerea;

[0029] Figure 7 The photos show the effects of Burkholderia pyrroreyi ZR-28 on the disease of living strawberry leaves infected with Botrytis cinerea.

[0030] Figure 8 This is a statistical bar graph showing the effect of Burkholderia pyrroreus ZR-28 treatment on the disease index of living strawberry leaves infected with Botrytis cinerea;

[0031] Fig. 9 This is a statistical bar graph of the control effect of Burkholderia pyrroreyi ZR-28 on the disease of living strawberry leaves infected with Botrytis cinerea;

[0032] Fig.10 Photos showing the effect of Burkholderia pyrroreus ZR-28 on the disease of detached corn leaves infected with Helicoverpa maydis (a. blank control group, b. experimental group, c. positive control group);

[0033] Fig.11 This is a statistical bar graph showing the effect of Burkholderia pyrroreyi ZR-28 treatment on the lesion area of ​​detached corn leaves infected with Helicoverpa maydis.

[0034] Fig.12 The photos show the effects of Burkholderia pyrroreyi ZR-28 on the disease of living corn leaves infected with Helicoverpa maydis.

[0035] Fig.13 This is a statistical bar graph showing the effect of Burkholderia pyrroreus ZR-28 treatment on the disease index of living corn leaves infected with Helicoverpa maydis.

[0036] Fig.14 This is a statistical bar graph of the control effect of Burkholderia pyrroreyi ZR-28 on the disease of living corn leaves infected with Helicoverpa maydis;

[0037] Fig.15 The photos show the phenotypic effects of Burkholderia pyrroreyi ZR-28 on strawberry seedlings.

[0038] Fig.16 This is a statistical bar graph showing the effects of Burkholderia pyrroreyi ZR-28 treatment on some agronomic traits of strawberry seedlings (a. plant height, b. maximum leaf area, c. fresh weight, d. dry weight);

[0039] Fig.17 The photos show the phenotypic effects of Burkholderia pyrroreyi ZR-28 on corn seedlings.

[0040] Fig.18 This is a statistical bar graph showing the effect of Burkholderia pyrroreyi ZR-28 treatment on the plant height of corn seedlings;

[0041] Fig.19 This is a statistical bar graph showing the effect of Burkholderia pyrroreyi ZR-28 treatment on the root length of corn seedlings;

[0042] Fig. 20 This is a diagram showing the antagonistic effect of Burkholderia pyrroreus ZR-28 on two pathogens, namely, Helminthosporium maydis (lower) and Botrytis cinerea (upper).

[0043] Fig.21 This is a diagram showing the antagonistic effect of volatile substances produced by Burkholderia pyrroreyi ZR-28 on two pathogens, B. cinerea and B. maydis, where a is B. cinerea and b is maydis, and the scale is 1 cm. DETAILED DESCRIPTION

[0044] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0045] Example 1

[0046] Screening of strain ZR-28:

[0047] S1: Select fresh root, stem and leaf tissues of healthy yew plants, rinse with running water, air dry the surface moisture, cut into small sections and pieces, weigh 3g of each tissue, and rinse with sterile water 3 times in a clean bench. Each tissue part is first disinfected with 75% alcohol for 2 minutes, then soaked in 0.5% sodium hypochlorite solution for 1 minute, and finally rinsed with sterile water 5 times.

[0048] S2: Take 100 μL of the last sterile water rinse of each tissue and spread it evenly on the LB solid plate and PDA solid plate to check whether the disinfection is thorough. Dry the sterilized tissue pieces, put them in a mortar, add 3 mL of sterile water and grind them thoroughly. Take 1 mL of the supernatant and dilute it to 10 by 10-fold dilution method. -7 , take 10 -3 , 10 -4 , 10 -5 , 10 -6 , 10 -7.5100 μL of each dilution gradient solution was evenly spread on LB solid plates and PDA solid plates, and each dilution gradient of each tissue was repeated 3 times. The plates were incubated upside down in a 28°C constant temperature incubator for 2 to 3 days. LB solid plates were used to isolate endophytic bacteria, and PDA solid plates were used to isolate endophytic fungi.

[0049] S3: Activate the isolated bacterial strains and inoculate them in a triangular flask containing 50mL LB liquid culture medium. Cultivate them at 28℃ and 200r / min for 24h. The pathogenic fungi used as target bacteria need to be inoculated on a PDA solid plate and cultured at 28℃ for 3-5d for activation. The streak confrontation method was used to perform plate confrontation on B.Cinerea and B.Maydis: the pathogenic fungi were punched with a 6mm diameter puncher and inoculated in the center of the PDA solid plate. 10μL of the sterile fermentation liquid of the bacteria to be tested was evenly streaked and inoculated at a distance of 2cm from the center of the pathogen at the point of contact. Three replicates and a blank control were set for each pathogen. After 7d of culture, an antagonistic strain was finally screened and named ZR-28.

[0050] Example 2

[0051] Identification of the antagonistic strain ZR-28:

[0052] The strain ZR-28 was inoculated on LB medium to form round colonies, which were yellow, smooth, shiny, with neat edges and no fluorescence. Gram staining was red, and it was a Gram-negative bacterium. See attached Figure 1 The 16SrDNA fragment of the ZR-28 strain was amplified, and the amplification results are shown in the attached Figure 2 , the fragment size is approximately 1800bp.

[0053] The sequencing results of the 16S rDNA amplification products of the strains were compared with the known sequences in GenBank using BLAST, and the strain sequences with the closest relationship were downloaded. The MEGA7.0 software and the Neighbor-Join method were used to build a phylogenetic tree. The results of the phylogenetic tree construction are shown in the attached figure. Figure 3. In the homology comparison results of NCBI, the homology between the antagonistic strain ZR-28 and Burkholderia sp. reached 100%. The phylogenetic analysis results showed that the antagonistic strain ZR-28 was closely related to Burkholderia pyrrocinia (NR-116156.1), Burkholderia pyrrocinia (NR-112060.1) and Burkholderiapyrrocinia (NR-029210.1), and they were clustered into one branch with a bootstrap support rate of 90%. Combined with the morphological characteristics of the antagonistic strain and the results of molecular biological identification, the antagonistic strain ZR-28 was identified as Burkholderiapyrrocinia.

[0054] Example 3

[0055] S21. The strain ZR-28 was inoculated on a new LB solid culture medium and placed at 28°C for constant temperature culture activation. 100 ml of the activated bacterial solution was aspirated and spread on the LB solid culture medium. After 24 hours, a single colony was picked out and inoculated into the LB liquid culture medium. The culture was shaken at a constant temperature of 28°C and a rotation speed of 200 r / min for 30 hours to obtain the strain fermentation liquid for use.

[0056] S22. Centrifuge part of the sterile fermentation broth at 6000 r / min in a high-speed centrifuge for 5 min, aspirate the supernatant, and filter the bacteria using a 0.22 μm aqueous phase filter to obtain a sterile fermentation broth.

[0057] Example 4

[0058] Antibacterial effect test of Burkholderia pyrroreyi ZR-28:

[0059] The plate confrontation method was used to determine the broad-spectrum antibacterial activity of Burkholderia pyrrolate ZR-28 against plant pathogens such as Helminthosporium maydis, Botrytis cinerea, Aspergillus flavus, Rhizoctonia solani, Fusarium oxysporum, Fusarium laminarum, Curvularia lunulata, Verticillium dahliae, Colletotrichum spp., Pseudomonas aeruginosa, Colletotrichum gloeosporioides, Fusarium graminearum, Alternaria solani, Alternaria alternata, Fusarium solani and Colletotrichum boninensis. The results are shown in Table 1. Among them, the antagonistic effect of Burkholderia pyrrolate ZR-28 against two pathogens such as Helminthosporium maydis and Botrytis cinerea in the plate was shown in Table 1. Fig. 20 shown.

[0060] Table 1

[0061]

[0062] Among the existing pyrroburkholderia, the inhibition rates of pyrroburkholderia F12 against Rhizoctonia solani, black rot fungus of apple, sclerotinia, Fusarium oxysporum, Xylaria, Pseudomonas vesmeri, Fusarium graminearum and Fusarium verticillium are 71.6%, 68.5%, 76.63%, 64.1%, 72.1%, 64.2%, 71.8% and 67.6%, respectively; the inhibition rates of pyrroburkholderia JK-SH007 against Aspergillus chrysogenum, Phomopsis spp. and Fusarium septempunctata are 58%, 46% and 72%, respectively; however, the inhibition rates against Aspergillus flavus, Aspergillus niger, Pseudomonas aeruginosa, Colletotrichum sphaerocephalus and Colletotrichum boninensis have not been studied yet.

[0063] According to the above data, the strain has a more significant antagonistic effect on several common leaf disease pathogens such as Botrytis cinerea, B. maydis, C. lunata, C. fructicola, P. theae, and A. alternata, with the inhibition rate reaching more than 75%.

[0064] The binary confrontation culture method was used to determine whether the volatile substances produced by Burkholderia pyrroreus ZR-28 also have antagonistic effects on pathogens such as B. cinerea and B. maydis (e.g. Fig.21 As shown. After 7 days of confrontation treatment, the mycelium of B. cinerea pathogen in the blank control group covered half of the PDA medium, while the mycelium growth of the pathogen in the treatment group was inhibited, and the inhibition rate of ZR-28 reached 60.34%; compared with the mycelium growth rate of B. maydis pathogen in the blank control group, the mycelium growth of the pathogen in the treatment group was relatively slow, and the inhibition rate of ZR-28 was 59.43%. The experimental results show that the volatile substances produced by the candidate strains have the ability to inhibit the growth of pathogen mycelium.

[0065] Embodiment 5:

[0066] Evaluation of the growth-promoting potential of Burkholderia pyrroreus ZR-28

[0067] Burkholderia pyrroreus ZR-28 was inoculated into different culture media (inorganic phosphorus medium PVK, calcium phytate medium, nitrogen-free medium Ashby, CAS medium) and cultured according to the growth of the colonies on each culture medium ( Figure 4 ) to determine its ability to dissolve phosphorus, fix nitrogen, and secrete iron carriers; add a colorimetric reagent to the sterile fermentation broth of Burkholderia pyrroreus ZR-28 and an IAA standard solution, and determine its ability to secrete IAA based on the color development of the reagent.

[0068] Phosphorus dissolving ability: Strain ZR-28 did not produce a transparent zone on the two culture media, indicating that strain ZR-28 does not have the ability to dissolve inorganic phosphorus and organic phosphorus.

[0069] Nitrogen fixation ability: strain ZR-28 cannot grow normally on nitrogen-free medium (Ashby), indicating that strain ZR-28 does not have the ability to fix nitrogen.

[0070] Ability to secrete siderophores: The strain ZR-28 can grow on CAS medium and form an orange halo around the colonies, indicating that the strain ZR-28 has the ability to secrete siderophores.

[0071] IAA secretion ability: The ability of strain ZR-28 to secrete IAA was tested using Salkowski reagent. The results showed that the fermentation broth of strain ZR-28 could make the Salkowski reagent turn red, indicating that strain ZR-28 has the ability to secrete IAA. According to the IAA standard curve (Y = 0.0589x + 0.0863, R 2 =0.9955), the content of IAA secreted by strain ZR-28 in LB liquid culture medium containing tryptophan was 1.338 μg / L.

[0072] In summary, strain ZR-28 has the ability to secrete siderophores and IAA, so strain ZR-28 has certain growth-promoting potential.

[0073] Example 6

[0074] In vitro strawberry leaf control test:

[0075] Healthy strawberry seedling leaves with similar growth conditions were selected. After surface disinfection, the sterile fermentation liquid, LB liquid culture medium and chemical agent Procymidone prepared in Example 3 were sprayed on the surface of each leaf. Three leaves were set for each treatment group, wherein the sterile fermentation liquid treatment group was used as the experimental group, the LB liquid culture medium treatment group was used as the blank control group, and the chemical agent Procymidone treatment group was used as the positive control group. After spraying for 12 hours, the strawberry seedling leaves of each treatment group were pierced with an inoculation needle and inoculated with Botrytis cinerea. The inoculated leaves were placed in a culture dish containing moistened sterile filter paper and cultured in light-dark alternation at 28°C for 7 days. The above test was performed 3 times to observe the incidence of the leaves ( Figure 5 ), and the lesion area was counted ( Figure 6 ).

[0076] The results showed that the lesion area of ​​the blank control group was 3.67 cm 2The lesion area of ​​the experimental group was reduced by 0.62 times compared with that of the control group, which was significantly smaller than that of the blank control group. No lesions appeared on the leaves of the positive control group. It can be seen that the sterile fermentation liquid of Burkholderia pyrroreus ZR-28 has a good inhibitory effect on the pathogenicity of Botrytis cinerea on detached strawberry leaves.

[0077] In vivo strawberry leaf control experiment: Select strawberry seedlings with similar growth, disinfect the leaf surface, spray the sterile fermentation liquid, LB liquid culture medium and chemical agent Procymidone prepared in Example 3 on the surface of each leaf, and each treatment group is provided with 3 leaves, wherein the sterile fermentation liquid treatment group is used as the experimental group, the LB liquid culture medium treatment group is used as the blank control group, and the chemical agent Procymidone treatment group is used as the positive control group. After spraying for 24 hours, a spore suspension of Botrytis cinerea is evenly sprayed on the surface of the strawberry seedling leaves of each treatment group using a spray bottle, and the strawberry seedlings are cultivated for 14 days under normal conditions. The above test is carried out 3 times in total, and the incidence of the strawberry seedling leaves is observed ( Figure 7 ) and calculate the disease index of strawberry seedlings ( Figure 8 ) and control effect ( Fig. 9 ), the classification of disease levels refers to Table 2:

[0078] Table 2

[0079] Disease grade The proportion of lesion area to leaf area Level 0 No disease spots; Level 1 The lesion area is less than 5% of the total area; Level 2 5% ≤ lesion area < 20% of the total area Level 3 20% ≤ lesion area < total area 35% Level 4 35% ≤ lesion area < 50% of total area Level 5 Lesion area ≤ 50%

[0080] Disease index = ∑ (disease level × total number of leaves at that level) / (highest disease level × total number of leaves) × 100%

[0081] Control effect = (control group disease index - treatment group disease index) / control group disease index × 100%

[0082] The results showed that after spraying the spore suspension of Botrytis cinerea, the disease index of the blank control group was 95.23%. In the early stage of pathogen infection, water-soaked spots or inverted "V"-shaped spots appeared on the base leaves. In the late stage of the disease, all the leaves died, and gray-white mold-like substances were generated on the spots of leaves with high humidity. The disease index of the experimental group was 51.25%, and a small number of diseased leaves appeared at the base of the strawberry seedlings, and the control effect reached 41.33%. The disease index of the positive control group was 14.22%, and the control effect of the positive control group procymidone group was 75.33%. It can be seen that the sterile fermentation liquid of Burkholderia pyrrolate ZR-28 has an excellent biological control effect on Botrytis cinerea on living strawberry leaves, which is similar to the control effect of the chemical agent procymidone.

[0083] Example 7

[0084] In vitro corn leaf control experiment:

[0085] Healthy corn seedling leaves with similar growth conditions were selected. After surface disinfection, equal amounts of the sterile fermentation liquid, LB liquid culture medium and chemical agent carbendazim prepared in Example 3 were sprayed on the surface of each leaf. Three leaves were set in each treatment group, wherein the sterile fermentation liquid treatment group was used as the experimental group, the LB liquid culture medium treatment group was used as the blank control group, and the chemical agent carbendazim treatment group was used as the positive control group. After 12 hours of spraying treatment, the corn seedling leaves of each treatment group were inoculated with Zea mays flat navel helminth spores. The inoculated leaves were placed in a culture dish containing moist sterile filter paper, and were cultured in light-dark alternation at 28°C for 7 days to keep moist. The above test was carried out 3 times in total, and the disease condition of the leaves was observed ( Fig.10 ), and the lesion area was counted ( Fig.11 ).

[0086] The results showed that the lesion area of ​​the blank control group was 1.22 cm 2 The lesion area of ​​the experimental group was 0.82 cm 2 , which was significantly lower than that of the blank control group. No lesions appeared on the leaves of the positive control group. The experimental results showed that the sterile fermentation liquid of Burkholderia pyrroreus ZR-28 had a good inhibitory effect on the pathogenicity of Helicoverpa maydis on detached corn leaves.

[0087] In vivo corn leaf control experiment: The experimental field was divided into two sections with an area of ​​1m 2 The test plots were arranged in a row, with each plot spaced 50 cm apart. When the corn seedlings in each plot were in the trumpet stage with consistent growth, the sterile fermentation liquid, LB liquid culture medium and chemical agent carbendazim prepared in Example 3 were sprayed on the surface of the leaves of the corn seedlings in each plot using a spray bottle. A randomized block design was adopted, and three plots were set for each treatment group, wherein the sterile fermentation liquid treatment group plot was used as the experimental group, the LB liquid culture medium treatment group plot was used as the blank control group, and the chemical agent carbendazim treatment group plot was used as the positive control group. After spraying for 24 h, a spore suspension of Zea mays was evenly sprayed on the surface of the leaves of the corn seedlings in each treatment group plot using a spray bottle. The corn seedlings were cultivated for 30 d under normal conditions, and the incidence of corn leaves in all treatment group plots was observed and recorded ( Fig.12 ) and calculate the disease index of corn seedlings ( Fig.13 ) and control effect ( Fig.14 ), the classification of disease levels refers to Table 3:

[0088] Table 3

[0089]

[0090]

[0091] Disease index = ∑ (disease level × total number of plants at that level) / (highest disease level × total number of plants) × 100%

[0092] Prevention and treatment effect = (control group disease index - treatment disease index) / control group disease index × 100%

[0093] The results showed that after the corn seedlings in the blank control group were sprayed with the spore suspension of Zea maydis, the final statistical disease index was 88.17%. In the early stage of pathogen infection, small brown spots appeared on the base leaves, and the spots gradually connected into long ovals and spread upward. In the late stage of the disease, the top leaves of the corn plants were also infected, and the elliptical or circular spots were densely connected into pieces, and the whole plant was infected; the disease index of the experimental group was 69.12%, and a small number of brown spots appeared on the base leaves of the corn plants, and the control effect reached 38.22%; the disease index of the positive control group was 16.98%, and the control effect was 75.32%. It can be seen that the sterile fermentation liquid of Burkholderia pyrrolate ZR-28 has an excellent biological control effect on Zea maydis on living corn leaves, which is close to the control effect of the chemical agent carbendazim.

[0094] Example 8

[0095] Growth promotion assay of Burkholderia pyrroreyi ZR-28 on strawberry seedlings:

[0096] Select the strawberry seedlings with similar growth in sterile soil pots, and irrigate the roots of each strawberry seedling with 20 mL 1×10 5 CFU / mL of the fermentation broth prepared in Example 3, 20 mL of LB liquid medium, 3 potted plants were set for each treatment group, wherein the fermentation broth treatment group was used as the experimental group, and the LB liquid medium treatment group was used as the blank control group. After root irrigation treatment, the potted plants of each treatment group were placed in a greenhouse for 21 days. The above test was carried out 3 times in total, and the phenotypes of the strawberry seedlings were observed and recorded ( Fig.15 ) and counted various growth indicators of strawberry seedlings ( Fig.16 ).

[0097] The results showed that after the strawberry seedlings were treated with the fermentation liquid of the strain of Burkholderia pyrrocephala ZR-28 and cultured for 21 days, the aboveground phenotypes were significantly different compared with the blank control group, among which the plant height increased by 75.02% compared with the blank control group, the maximum leaf area increased by 72% compared with the blank control group, the fresh weight increased by 35.83% compared with the control group, and the dry weight increased by 29.91% compared with the blank control group. It can be seen that the fermentation liquid of the strain of Burkholderia pyrrocephala ZR-28 can promote the growth of strawberry seedlings.

[0098] Growth promotion test of corn seeds: corn seeds with similar germination degree after germination were selected and sown in sterile soil pots. Each corn seed was root-irrigated with 20 mL 1×10 5 CFU / mL of the fermentation broth of the strain prepared in Example 3, 20 mL of LB liquid medium, 5 potted plants were set for each treatment group, wherein the fermentation broth treatment group was used as the experimental group, and the LB liquid medium treatment group was used as the blank control group. After root irrigation treatment, each treatment group was placed in a greenhouse for 14 days. The above test was carried out 3 times in total, and the phenotype of the corn seedlings was observed and recorded ( Fig.17 ), and measure and count the plant height growth index of corn seedlings ( Fig.18 ) and root length growth index ( Fig.19 ).

[0099] The results showed that compared with the blank control group, the plant height and root length of the experimental group were significantly different, among which the plant height increased by 43.41% and the root length increased by 34.11% compared with the blank control group. In addition, compared with the blank control group, the number and length of lateral roots of corn seedlings increased significantly after treatment with the fermentation liquid of the strain, which may allow the plants to absorb more nutrients, thereby promoting the growth of the aboveground part; after field root irrigation treatment, the plant height of the experimental group increased by 29.03%. It can be seen that the fermentation liquid of the strain of Burkholderia pyrroreus ZR-28 can promote the growth of corn seedlings.

[0100] In summary, the Burkholderia pyrrolate ZR-28 provided in this application has the ability to secrete siderophores and IAA, has excellent growth-promoting effects on plants such as strawberries and corn, has significant biological control effects on strawberry gray mold and corn leaf spot, and has good antagonistic effects on a variety of plant pathogenic microorganisms, providing a new biological solution for plant disease control and plant growth promotion for agricultural production. Through in-depth research and application development, Burkholderia pyrrolate ZR-28 is expected to provide more environmentally friendly and efficient biological pesticides and plant growth promoters for agricultural production, and promote the sustainable development of agriculture.

[0101] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A Burkholderia pyrrocinia, named ZR-28, deposited in the General Microbiology Center of China Microorganism Culture Collection Administration, with the deposit address at No. 3, Yard No. 1, Beichen Road West, Chaoyang District, Beijing, the deposit date is May 17, 2024, and the deposit number is CGMCC NO.30588.

2. Use of Burkholderia pyrroreus ZR-28 as claimed in claim 1 in at least one of secreting siderophore and producing indoleacetic acid.

3. Use of a preparation containing the Burkholderia pyrroreus ZR-28 according to claim 1 as an active ingredient in agriculture.

4. A bacterial agent containing the Burkholderia pyrroreus ZR-28 according to claim 1.

5. Use of the Burkholderia pyrrocephala ZR-28 according to claim 1 or the bacterial agent according to claim 4 in promoting plant growth, characterized in that: The plants include Rosaceae and Poaceae.

6. A plant growth agent for promoting plant growth containing the Burkholderia pyrrolate ZR-28 according to claim 1 or the bacterial agent according to claim 4, characterized in that: The plants include Rosaceae and Poaceae.

7. A medicament comprising the Burkholderia pyrroreus ZR-28 according to claim 1 or the bacterial agent according to claim 4.

8. The drug according to claim 7, characterized in that The drug can be used for biological control of strawberry gray mold and corn leaf spot.

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