Microbacterium R1 and application thereof

Abstract

This invention belongs to the field of microbial technology, specifically relating to a strain of Microbacterium R1 and its applications. The Microbacterium sp. R1 provided by this invention is deposited at the China Center for Type Culture Collection (CCTCC), with accession number CCTCC M 2024851. This strain exhibits significant control effects against clubroot disease. Verification through examples shows that Microbacterium R1 can inhibit the germination rate of dormant spores of Clubroot by 30.4%. In pot experiments, it can reduce the disease index of clubroot by 48.3%, and in field trials, it can reduce the seedling incidence of clubroot by 30.33% and the disease index by 54.61%. The treated group showed significantly higher rapeseed plant height, growing point height, number of green leaves, total number of leaves, rootstock diameter, fresh weight, effective length of the main inflorescence at the silique stage, and number of effective siliques in the main inflorescence compared to the control group. After treatment with the R1 strain, rapeseed yield increased by 77.53%, and thousand-grain weight increased by 9.4%.

Description

Technical Field

[0001] This invention belongs to the field of microbial technology, specifically relating to a strain of microbacterium R1 and its applications. Background Technology

[0002] Clubroot is a widespread plant disease caused by Plasmodiophora brassicae, which can lead to a severe decline in the yield of cruciferous crops, or even complete crop failure. Moreover, soil contaminated with clubroot will remain infected for a long time, seriously threatening the sustainable production and industrial development of cruciferous crops. Summary of the Invention

[0003] The purpose of this invention is to provide a strain of Microbacterium sp. R1 to achieve green control of clubroot disease and enrich the microbial resources for the prevention and control of clubroot disease.

[0004] This invention provides a strain of Microbacterium sp. R1, which is deposited at the China Center for Type Culture Collection, with accession number CCTCC M 2024851.

[0005] The present invention also provides a microbial agent, which includes the microbacterium R1 described in the above technical solution.

[0006] Preferably, the OD of the bacterial agent 600 The value ranges from 0.3 to 1.5.

[0007] The present invention also provides the application of the microbacterium R1 described in the above technical solution or the bacterial agent described in the above technical solution in the prevention and control of plant clubroot disease and / or the inhibition of clubroot bacteria.

[0008] Preferably, the plant includes rapeseed.

[0009] This invention also provides a method for preventing and controlling clubroot disease in rapeseed, comprising the following steps:

[0010] Before sowing, rapeseed seeds are first treated with the microbial agent described in the above technical solution to obtain first-treated rapeseed seeds;

[0011] The rapeseed seeds treated with the first treatment were sown, and the sown rapeseed seeds were then treated with the microbial agent described in the above technical solution.

[0012] Preferably, the first treatment method includes soaking; the soaking time is 4 to 6 hours, and the soaking temperature is 28°C.

[0013] Preferably, the second treatment method includes root irrigation; the root irrigation is performed 3 times, and the time interval between two adjacent root irrigations is 20 to 55 days.

[0014] Preferably, the first root irrigation is performed on the first day after sowing.

[0015] Preferably, the dosage of the microbial agent is 2.5 L / 10 m² for each root drenching. 2 .

[0016] Beneficial effects:

[0017] This invention provides a strain of Microbacterium sp. R1, deposited at the China Center for Type Culture Collection (CCTCC) with accession number CCTCC M 2024851. This strain exhibits significant control effects against clubroot disease, particularly in rapeseed. Verification through examples shows that Microbacterium R1 can inhibit the germination of dormant spores of the clubroot fungus, achieving an inhibition rate of 30.4%. In pot experiments, it reduced the clubroot disease severity index by 48.3%. In field trials, after 76 days of treatment with R1 strain, the incidence of clubroot disease in seedlings decreased by 30.33%, and the severity index decreased by 54.61%. After 100 days of treatment with R1 strain, the treated rapeseed showed significantly higher plant height, growing point height, number of green leaves, total number of leaves, rootstock diameter, and fresh weight compared to the control group. Field trials at the pod-setting stage of rapeseed revealed that R1 strain treatment significantly increased plant height, effective length of the main inflorescence, and the number of effective pods in the main inflorescence. Actual yield measurements in field trials revealed that treatment with strain R1 increased rapeseed yield by 77.53% and thousand-grain weight by 9.4%.

[0018] Biological Preservation Information

[0019] Microbacterium R1, biologically classified as Microbacterium sp., was deposited on April 30, 2024, at the China Center for Type Culture Collection (CCTCC), Wuhan University, Wuhan, China, with accession number CCTCC NO: M 2024851. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below.

[0021] Figure 1 The phylogenetic tree and morphological characteristics of strain R1;

[0022] Figure 2 The germination rate of dormant spores of *Plasmodiophora* in Example 2;

[0023] Figure 3 The root swelling phenotypes of rapeseed in the control group (Pb) and treatment group (Pb+R1) after 35 days of inoculation with clubroot fungus in Example 3;

[0024] Figure 4The disease index of rapeseed in the control group (Pb) and treatment group (Pb+R1) after 35 days of inoculation with clubroot fungus was statistically analyzed in Example 3, n=32;

[0025] Figure 5 The root diameter of rapeseed in the control group (Pb) and treatment group (Pb+R1) after 35 days of inoculation with clubroot fungus in Example 3 is n=32;

[0026] Figure 6 The root weight of rapeseed in the control group (Pb) and treatment group (Pb+R1) after 35 days of inoculation with clubroot fungus in Example 3, n=32;

[0027] Figure 7 The phenotypes of clubroot disease in rapeseed seedlings were observed 76 days after sowing in the control group (Pb) and treatment group (Pb+R1) in Example 4.

[0028] Figure 8 The incidence of clubroot disease in rapeseed seedlings was measured 76 days after sowing in the control group (Pb) and treatment group (Pb+R1) in Example 4.

[0029] Figure 9 The disease index of clubroot disease in rapeseed seedlings was measured 76 days after sowing in the control group (Pb) and treatment group (Pb+R1) in Example 4.

[0030] Figure 10 The plant height of rapeseed in the control group (Pb) and treatment group (Pb+R1) 100 days after sowing in Example 4;

[0031] Figure 11 The height of the rapeseed growth point in the control group (Pb) and treatment group (Pb+R1) 100 days after sowing in Example 4;

[0032] Figure 12 The total number of rapeseed leaves in the control group (Pb) and treatment group (Pb+R1) 100 days after sowing in Example 4;

[0033] Figure 13 The total number of rapeseed leaves in the control group (Pb) and treatment group (Pb+R1) 100 days after sowing in Example 4;

[0034] Figure 14 The rootstock diameter of rapeseed in the control group (Pb) and treatment group (Pb+R1) 100 days after sowing in Example 4 was [not specified].

[0035] Figure 15 The fresh weight of rapeseed in the control group (Pb) and treatment group (Pb+R1) 100 days after sowing in Example 4;

[0036] Figure 16The plant height of rapeseed at the pod stage in the control group (Pb) and treatment group (Pb+R1) in Example 4;

[0037] Figure 17 The effective length of the main inflorescence during the pod stage of rapeseed in the control group (Pb) and treatment group (Pb+R1) in Example 4;

[0038] Figure 18 The effective number of main inflorescence siliques in the control group (Pb) and treatment group (Pb+R1) during the silique stage of rapeseed in Example 4;

[0039] Figure 19 The yield of rapeseed in the control group (Pb) and the treatment group (Pb+R1) in Example 4;

[0040] Figure 20 The thousand-grain weights of rapeseed in the control group (Pb) and treatment group (Pb+R1) in Example 4 are given. Detailed Implementation

[0041] This invention provides a strain of Microbacterium sp. R1, which is deposited at the China Center for Type Culture Collection, with accession number CCTCC M 2024851.

[0042] The present invention also provides a microbial agent, which includes the microbacterium R1 described in the above technical solution.

[0043] In this invention, the OD of the bacterial agent 600 The value is preferably 0.3-1.5, more preferably 0.3 or 1.5; the preparation method of the bacterial agent preferably includes: culturing microbacterium R1 in LB liquid medium; the culturing time is preferably 3 days; the culturing temperature is preferably 28℃.

[0044] The present invention also provides the application of the microbacterium R1 described in the above technical solution or the bacterial agent described in the above technical solution in the prevention and control of plant clubroot disease and / or the inhibition of clubroot bacteria.

[0045] In this invention, the plant includes rapeseed; the inhibition of clubroot fungus preferably includes the inhibition of clubroot fungal spore germination.

[0046] This invention also provides a method for preventing and controlling clubroot disease in rapeseed, comprising the following steps:

[0047] Before sowing, rapeseed seeds are treated with the microbial agent described in the above technical solution to obtain first-treated rapeseed seeds; the first-treated rapeseed seeds are sown, and the sown rapeseed seeds are then subjected to a second treatment.

[0048] This invention utilizes the microbial agent described in the above-mentioned technical solution to perform a first treatment on rapeseed seeds, obtaining first-treated rapeseed seeds. In this invention, the first treatment preferably includes soaking; the OD of the microbial agent used for soaking... 600 The value is preferably 0.3; the soaking time is preferably 4-6 hours, more preferably 5 hours; the soaking temperature is preferably 28°C.

[0049] After obtaining the first-treated rapeseed seeds, the present invention sows the first-treated rapeseed seeds and uses the microbial agent described in the above technical solution to perform a second treatment on the sown rapeseed seeds.

[0050] In this invention, the second treatment preferably includes root irrigation; the OD of the fungal agent used for root irrigation is... 600 The preferred value is 1.5; the preferred number of root drenching sessions is 3; the preferred time for the first root drenching is the first day after sowing; the preferred time interval between two consecutive root drenching sessions is 20-30 days; the preferred time interval between the first and second root drenching sessions is 20 days, and the preferred time interval between the second and third root drenching sessions is 30 days; the preferred dosage of the microbial agent for each root drenching session is 2.5 L / 10m². 2 The method provided by this invention can effectively reduce the incidence and disease index of clubroot disease in rapeseed, significantly increase the height and fresh weight of rapeseed seedlings, and effectively increase yield and thousand-grain weight.

[0051] To further illustrate the present invention, the following detailed description of a strain of microbacterium R1 and its applications, in conjunction with the accompanying drawings and embodiments, is provided but should not be construed as limiting the scope of protection of the present invention.

[0052] In this embodiment of the invention, the significant differences in the data were determined by a t-test. The error bar is the mean ± standard deviation, and different letters indicate significant differences. "****" indicates p < 0.05.

[0053] Example 1

[0054] Identification of R1 strain

[0055] A bacterial strain R1 was isolated from the roots of European turnip ECD04, which is resistant to clubroot. The R1 strain was streaked on R2A agar medium for 2 days, and its colony morphology was observed. Figure 1 As shown in B.

[0056] Depend on Figure 1 As can be seen from B, the colony morphology of strain R1 is: smooth and pale yellow.

[0057] R2A liquid culture medium formulation: 3.2g of R2A liquid culture medium powder (Haibo Biotechnology), dissolved in 1000mL of distilled water by heating, and sterilized at 121℃ for 20min;

[0058] R2A agar medium formulation: Add 2g of agar to every 200mL of liquid medium and sterilize at 121℃ for 20min.

[0059] The R1 strain was cultured overnight in R2A liquid medium with shaking, and then the DNA of the R1 strain was extracted using the alkaline lysis method. The specific steps are as follows:

[0060] 6 μL of bacterial culture was added to 10 μL of Buffer I (25 mM NaOH, 0.2 mM EDTA, pH 12) solution and incubated at 95 °C for 30 min. Then, 10 μL of Buffer II (40 mM Tris-HCl, pH 7.5) was added and mixed thoroughly to obtain bacterial DNA. The DNA of strain R1 was amplified by PCR using primers 27F and 1492R to obtain the amplification product. The sequences of primers 27F and 1492R are as follows:

[0061] 27F: 5'-TACGGYTACCTTGTTACGACTT-3' (SEQ ID No. 1);

[0062] 1492R: 5'-AGAGTTTGATCMTGGCTCAG-3' (SEQ ID No. 2).

[0063] Amplification was performed using Pfu polymerase. The reaction mixture consisted of: 1.5 μL of amplified product, 0.5 μL of primer 27F, 0.5 μL of primer 1492R, 5 μL of 5× buffer, 2 μL of dNTPs, 0.5 μL of Pfu polymerase, and 1.5 μL of DNase-free and RNase-free water, for a total volume of 25 μL. The PCR program was as follows: 95℃ pre-denaturation for 2 min; 95℃ denaturation for 20 s, 55℃ annealing for 20 s, 72℃ extension for 30 s, 30 cycles; and 72℃ extension for 5 min. The PCR products were electrophoresed on a 1% agarose gel to detect the size of the amplified target band. The 16S rDNA sequence of strain R1 is as follows:

[0064]

[0065] Based on the results of 16S rDNA sequencing, a phylogenetic tree was constructed using the neighbor-joining method in Mega 7 software, as follows: Figure 1 As shown in Figure A.

[0066] according to Figure 1 China A, combined Figure 1 According to the results of the study, strain R1 was identified as belonging to the genus Microbacterium and named Microbacterium sp. R1. It was deposited at the China Center for Type Culture Collection on April 30, 2024, with accession number CCTCC M 2024851.

[0067] Example 2

[0068] Microbacterium sp. R1 inhibits the germination of dormant spores of *Plasmodiophora stearothermiae*.

[0069] 1. Dormant spores of *Plasmodiophora stylosa* were extracted and sterilized according to the method described in the literature (Bi Kai. Multi-omics study reveals the molecular mechanism of growth, development and pathogenesis of *Plasmodiophora stylosa* [D]. Huazhong Agricultural University, 2017.).

[0070] 2. Place a layer of high-temperature sterilized filter paper in a sterile 20cm diameter petri dish. Sterilize rapeseed seeds with 50v / v% 84 disinfectant for 15 minutes, rinse with sterile water 6-7 times, and place 100 seeds in each petri dish. Add 10mL of sterile water, seal the dish, and place it in a plant culture room for cultivation. After the rapeseed seeds have sprouted roots, add sterile water to the dish as needed. After culturing for 5-10 days, collect the culture solution and filter it through a 0.22μm bacterial filter to obtain the rapeseed root exudate solution.

[0071] 3. Preparation of bacterial fermentation broth: Add 5 mL of R2A liquid culture medium to a 30 mL sterile EP tube. Take a small amount of fresh Microbacterium sp. R1 cells from the R2A culture dish and inoculate them into the R2A liquid culture medium. Incubate at 28°C with shaking for 3 days, then centrifuge. Collect the supernatant and filter it through a 0.22 μm bacterial filter to obtain the R1 bacterial fermentation broth.

[0072] 4. Dormant spores of *Plasmodiophora* were divided into treatment and control groups, with six 1 mL centrifuge tubes in each group. 500 μL of a 4 × 10⁻⁶ concentration was added to each tube. 8 Centrifuge clean, dormant *Plasmodiophora* spores / mL at 8000 rpm for 3 min, discard the supernatant, and then proceed as follows:

[0073] Treatment group: Add 500 μL of R1 bacterial fermentation broth and vortex mix.

[0074] Control group: Add 500 μL of root exudate and vortex mix.

[0075] Then, the mixed systems were placed in a rapeseed culture room and cultured in the dark for 3 days. Microscopic observation: 100 μL of each tube was mixed with 10 μL of DAPI dye, and slides were prepared. The slides were observed and photographed using a fully motorized upright fluorescence microscope (BX63). Six images were collected from each group. After spore counting, the inhibition rate of the strain on the germination of dormant spores of *Plasmodiophora stylosa* was calculated. The results are as follows: Figure 2 As shown.

[0076] Spore germination inhibition rate (100%) = (germination rate of dormant spores in control group - germination rate of dormant spores in treatment group) × 100% / germination rate of dormant spores in control group.

[0077] Depend on Figure 2 It can be seen that the germination rate of the control group was 80.86%, and the germination rate of the treatment group was 56.25%. It can be calculated that the inhibition rate of strain R1 on the germination of dormant spores of Plasmodiophora is 30.44%.

[0078] Example 3

[0079] Microbacterium sp.R1 pot experiment

[0080] After centrifuging the R1 bacterial fermentation broth prepared in step 3 of Example 2, the bacterial cells were collected, and sterile water was added to adjust its OD. 600 Values ​​were prepared to obtain OD values. 600 =0.4 R10 bacterial culture and OD 600 Prepare R10 bacterial culture with a concentration of 1.5 for later use.

[0081] Rapeseed seeds were disinfected with 50% v / v 84 disinfectant for 15 minutes and rinsed 6-7 times with sterile water. They were then divided into a control group (Pb) and a treatment group (Pb+R1), with 32 seeds in each group, and treated as follows:

[0082] Treatment group (Pb+R1): Rapeseed seeds were subjected to OD... 600 After soaking in R1 bacterial solution at 0.4 for 1 hour, the rapeseed was sown. Nine days after sowing, each rapeseed plant was treated with 5 mL of R1 bacterial solution (OD200). 600 =1.5) Root irrigation; On the 10th day after sowing, inoculate each rapeseed plant with 1 mL of 9×10⁻⁶ solution. 6 The root drenching method was to inoculate the plant with dormant spores / mL of *Plasmodiophora stearothermiae*. Subsequently, the plant was drenched once a week with R1 bacterial solution, with 5 mL of R1 solution per plant each time, and the concentration of R1 solution was approximately 3 × 10⁻⁶ each time. 9 cfu / mL (OD) 600 =1.5), and the treatment lasted for 3 weeks.

[0083] Control group (Pb): Rapeseed seeds were soaked in water for 1 hour before sowing. Nine days after sowing, each rapeseed plant was irrigated with 5 mL of water. On the 10th day after sowing, each rapeseed plant was inoculated with 1 mL of a 9×10⁻⁶ solution. 6 The dormant spores of *Plasmodiophora* with a concentration of spores / mL were inoculated by root irrigation; subsequently, the roots were irrigated with clean water once a week, with 5 mL of water per rapeseed plant each time, for a total of 3 weeks.

[0084] (1) Disease index of rapeseed inoculated with clubroot fungus 35 days later: The rapeseed was removed from the soil with tweezers to minimize root damage. After rinsing off the soil from the rapeseed roots, the disease index of clubroot was statistically analyzed. The results are as follows: Figures 3-4 As shown.

[0085] Disease Index (DI) = (1n1 + 3n3 + 5n5) × 100 / 5N t

[0086] Prevention and control efficacy (%) = (Disease index of control - Disease index of treatment) × 100% / Disease index of control

[0087] Where n1, n3, and n5 are the number of rapeseed plants with disease severity levels of 1, 3, and 5, respectively, and N t This refers to the total number of rapeseed plants. The grading criteria for clubroot disease using the disease index in this study are as follows: No tumors on the roots and normal root growth and development (Grade 0); A few tumors on the main root or lateral roots (Grade 1); Medium to large tumors on the main root or hypocotyl, with obvious large nodular or spherical masses, which affect the growth of the plant to a certain extent (Grade 3); Large spindle-shaped tumors on both the main root and lateral roots, which seriously affect the growth of the plant (Grade 5).

[0088] Depend on Figure 3 It can be seen that 35 days after inoculation with clubroot bacteria, the roots in the control group showed significant swelling, while the swelling symptoms in the treatment group were alleviated; Figure 4 It can be seen that the disease index of the control group was 58, while that of the treatment group was 30. The calculated prevention and control effect was 48.3%.

[0089] (2) After calculating the disease index, the root length and root weight of the treatment group (Pb+R1) and the control group (Pb) were also statistically analyzed. The results are as follows: Figure 5 and Figure 6 As shown.

[0090] Depend on Figure 5 and Figure 6 It can be seen that after treatment with R1, root diameter and root weight decreased significantly. The pot experiment in this embodiment shows that strain R1 has a good biocontrol effect, which can significantly reduce the disease index and alleviate the symptoms of clubroot swelling.

[0091] Example 4

[0092] Microbacterium sp.R1 field trial

[0093] 1. On September 28, 2022, 12 plots were set up in fields with severe clubroot disease in Zhijiang City, Hubei Province. Each plot was 5m long and 2m wide, with 7 rows of rapeseed planted parallel to the length, with about 20 plants per row. The two outermost rows were used as protection rows and were not included in the subsequent statistics. The plots were divided into a control group (Pb) and a bacterial solution treatment group (Pb+R1), with 6 plots in each group. Three plots in each group were used for disease index statistics during the seedling and flowering stages, and three plots were used for yield statistics.

[0094] A concentration of 6×10 was prepared according to the method described in Example 3. 8 cfu / mL (OD) 600 R1 bacterial culture (=0.3).

[0095] Bacterial treatment group (Pb+R1): After disinfection of rapeseed seeds of Zhongshuang 15, a concentration of 6×10⁻⁶ was used. 8 cfu / mL (OD) 600 The seeds were soaked in R1 bacterial solution (0.3%), incubated at 28°C for 5 hours, and then dried for later use. Sowing began the day after seed treatment. On the day of sowing, the seeds were irrigated once with bacterial solution, 2.5 L of a 6×10⁻⁶ concentration per plot. 8 cfu / mL (OD) 600 The R1 bacterial solution (0.3%) was applied twice, on the 21st and 76th day after sowing.

[0096] Control group (Pb): After disinfection, rapeseed seeds of Zhongshuang 15 were soaked in sterile water, incubated at 28℃ for 5 hours, and then dried for later use. Sowing began the day after seed treatment. On the day of sowing, each plot was irrigated with tap water once, with 2.5L of tap water used for each plot. Tap water was used again on the 21st and 76th days after sowing.

[0097] 2. Field trial investigation of clubroot disease in rapeseed

[0098] 76 days after sowing, approximately 50 rapeseed plants were randomly selected from a plot used to collect disease indices during the seedling and flowering stages. Their disease severity and disease index were statistically analyzed using the following methods. The results are as follows: Figures 7-9 As shown.

[0099] Incidence rate (%) = Number of rapeseed plants with disease × 100% / Number of rapeseed plants surveyed

[0100] Disease Index (DI) = (1n1 + 2n2 + 3n3 + 4n4) × 100 / 4N t

[0101] Where n1-n4 represent the number of rapeseed plants with disease severity levels 1 to 4, and N t This refers to the total number of rapeseed plants. Based on the severity of the disease, the condition is divided into five levels: 0-4. Level 0: No tumors on the roots, normal root development; Level 1: No disease on the main root, small tumors on some lateral roots and fibrous roots; Level 2: Mild disease on the main root, slightly swollen, obvious tumors on some lateral roots and fibrous roots; Level 3: Severe disease on the main root, abnormally swollen and cracked, obvious tumors on most lateral roots and fibrous roots, but the plant grows normally; Level 4: Almost no fibrous roots, the main root is rotten or dead, the plant is wilted or dead.

[0102] Depend on Figures 7-9 It can be seen that the disease incidence rate in the control group (Pb) was 94.9%, while that in the bacterial suspension treatment group (Pb+R1) was 66.12%, a decrease of 30.33%. The disease index of the control group (Pb) was 84.41, while that of the bacterial suspension treatment group (Pb+R1) was 38.31. The biocontrol effect of strain R1 on clubroot disease in rapeseed in the field was 54.61%.

[0103] 3. Statistical analysis of agronomic traits of rapeseed in field trials

[0104] One hundred days after sowing, the growth of rapeseed seedlings was statistically analyzed.

[0105] Four representative rapeseed plants were selected from each plot used to collect disease indices during the seedling and flowering stages, totaling 12 plants from each of the three plots in each group. Plant height, growing point height, number of green leaves, total number of leaves, rootstock diameter, and fresh weight were statistically analyzed. Plant height (cm) was the distance from the highest point of the plant to the cotyledonary node; growing point height (cm) was the distance from the center of the cotyledonary leaf to the cotyledonary node; leaf drop count was the total number of yellowed and fallen leaves; and fresh weight (g) was the weight of the rapeseed above the cotyledonary node. During the peak flowering period, nine rapeseed plants were selected from each treatment, and their plant height, fresh weight, and rootstock diameter were statistically analyzed.

[0106] The results are as follows Figures 10-15 As shown, by Figures 10-15 It can be seen that, compared with the control group (Pb), the rapeseed plant height in the bacterial solution treatment group (Pb+R1) increased by 32.42%, the height of the growing point increased by 32.94%, the number of green leaves increased by 42.71%, the total number of leaves increased by 23.16%, the root and stem diameter increased by 45.77%, and the fresh weight increased by 189.6%.

[0107] 4. Statistics on rapeseed yield in field experiments

[0108] (1) Variety evaluation: Five rapeseed plants were selected from each plot using the five-point sampling method to count the disease index during the seedling and flowering stages. Plant height, effective length of the main inflorescence, and number of effective siliques of the main inflorescence were counted. The results are as follows: Figures 16-18 The effective length of the main inflorescence is the length from the uppermost effective silique at the top of the main inflorescence to the point where an effective silique is attached at the base of the main inflorescence. The effective number of siliques in the main inflorescence refers to the number of siliques on the main inflorescence that have more than one normal seed.

[0109] Depend on Figure 16 , 17 and Figure 18 It can be seen that, compared with the control group (Pb), the rapeseed plant height, effective length of the main inflorescence, and effective number of siliques of the main inflorescence were significantly increased in the bacterial solution treatment group (Pb+R1) after treatment with strain R1.

[0110] (2) Actual yield measurement: Data were collected from each plot (10m). 2 The rapeseed was dried, and then theoretical yield and thousand-grain weight were measured. The thousand-grain weight was calculated by randomly selecting three plots for measurement. The results are as follows: Figure 15 and Figure 16 As shown.

[0111] Depend on Figure 19 and Figure 20 It can be seen that the yield of the control group (Pb) was 49.36 g / m³. 2 The yield of the bacterial culture treatment group (Pb+R1) was 87.63 g / m³. 2 The number of grains increased by 77.53%. The thousand-grain weight of the control group (Pb) was 5.85g, and the thousand-grain weight of the bacterial culture treatment group (Pb+R1) was 6.40g, an increase of 9.4%.

[0112] The above embodiments demonstrate that the strain R1 provided by the present invention has the potential to prevent clubroot disease in rapeseed.

[0113] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A strain of Microbacterium sp. R1, deposited at the China Center for Type Culture Collection, accession number CCTCC M 2024851.

2. A microbial agent, characterized in that, The bacterial agent includes the microbacterium R1 as described in claim 1.

3. The microbial agent according to claim 2, characterized in that, The OD of the bacterial agent 600 The value is 0.3 to 1.

5.

4. The application of the microbacterium R1 as described in claim 1 or the bacterial agent as described in any one of claims 2 to 3 in the prevention and control of plant clubroot disease and / or the inhibition of clubroot bacteria; wherein the plant is rapeseed.

5. A method for controlling clubroot disease in rapeseed, characterized in that, Includes the following steps: Before sowing, rapeseed seeds are first treated with the microbial agent described in claim 2 or 3 to obtain first-treated rapeseed seeds; The rapeseed seeds treated with the first treatment were sown, and the sown rapeseed seeds were then subjected to a second treatment using the microbial agent described in claim 2 or 3.

6. The method according to claim 5, characterized in that, The first treatment method includes soaking; the soaking time is 4-6 hours, and the soaking temperature is 28°C.

7. The method according to claim 5, characterized in that, The second treatment method includes root irrigation; The root irrigation is performed 3 times, with an interval of 20-55 days between two consecutive root irrigations.

8. The method according to claim 7, characterized in that, The first root irrigation should be done on the first day after sowing.

9. The method according to claim 7, characterized in that, The dosage of the microbial agent was 2.5 L / 10 m² for each root drenching. 2 .

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