Actinacidiphila reveromycinica 3-10 and its application in preventing and treating plant diseases

Abstract

The present application belongs to the technical field of microbial pesticides, and particularly relates to Actinacidiphila reveromycinica 3-10 and application thereof in preventing and treating plant diseases. The present application aims to provide a new option for biological prevention and treatment of plant diseases. The technical scheme of the present application is Actinacidiphila reveromycinica 3-10, which has a preservation number of CCTCC NO: M 20242102. The present application further provides application of Actinacidiphila reveromycinica 3-10 in preventing and treating plant diseases. It is found for the first time that the fermentation liquor of Actinacidiphila reveromycinica 3-10 can effectively prevent and treat plant diseases, damping-off and fusarium wilt.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of microbial pesticides, and specifically relates to Actinacidiphila reveromycinica 3-10 and its application in preventing and treating plant diseases. BACKGROUND

[0002] Plant diseases seriously affect the growth of plants, and thus lead to the decline of yield and quality, and are one of the main threats to agricultural production (Wang Xing'e et al., 2006). Plant fungal diseases such as wilt caused by Fusarium oxysporum and rhizoctonia solani caused by Rhizoctonia solani account for more than 70% of the whole plant diseases, and are the most important biological factors in the process of plant diseases (Huang Ruiluan et al., 2020). Plant oomycete diseases are important pathogenic bacteria causing vegetable diseases, among which the diseases caused by Pythium have a short incubation period, multiple re-infection times, rapid onset, and are easy to cause disease prevalence, resulting in serious loss of vegetable production.

[0003] In agricultural production, chemical pesticides are still widely used to prevent and treat plant diseases, but the long-term and large-scale use of chemical pesticides can lead to problems such as enhanced pathogen resistance, excessive pesticide residues, and environmental pollution. The methods of agricultural prevention and control such as crop rotation, soil sunning, drip irrigation, high ridge and mulching can only reduce the occurrence of diseases, and cannot quickly prevent and treat diseases once the diseases occur rapidly and spread. The use of microorganisms for biological control not only can have a good control effect on plant diseases, but also can reduce environmental pollution and is not easy to produce drug resistance, and has become a research hotspot for the prevention and treatment of plant diseases at home and abroad.

[0004] Actinomycetes is a special group of prokaryotes that can form branched hyphae and conidiospores, grow in mycelial form and mainly reproduce by spores. Actinomycetes are widely distributed in soil and have been widely used in biological control of plant diseases due to their ability to produce a variety of secondary metabolites (Bérdy, 2005). For example, Li Qingmeng et al. isolated and screened an antagonistic actinomycete Streptomyces naraensis from the tree of Sinobaium oldhamii in Lushan, Jiangxi, which had a relative inhibition rate of more than 90% on plant pathogenic fungi such as Magnaporthe oryzae (Li Qingmeng et al., 2013). Sun Yanzhong et al. found that Wuyi mycin produced by Streptomyces ahygroscopicus var. wuyiensis had a significant control effect on vegetable fungal diseases such as cucumber powdery mildew and gray mold (Sun Yanzhong et al., 2003). Mao Liangju et al. found that Mycostop, a kind of actinomycete living preparation produced by Streptomyces griseovidis, could be used to control some soil-borne plant diseases caused by Pythium spp., Fusariwn spp., etc. (Mao Liangju et al., 2016). Actinacidiphila reveromycinica is a kind of actinomycetes that can grow in acidic environment, which has unique physiological characteristics and ecological functions, but there is no report on the use of Actinacidiphila reveromycinica in the control of plant diseases. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a new choice for biological control of plant diseases.

[0006] The technical solution of the present application is Actinacidiphila reveromycinica 3-10, which has a preservation number of CCTCC NO: M 20242102.

[0007] The present application also provides the use of Actinacidiphila reveromycinica 3-10 in the control of plant diseases.

[0008] Specifically, the plant disease is late blight, damping-off and / or fusarium wilt.

[0009] Further, the host of the late blight is Solanaceae plant.

[0010] Still further, the Solanaceae plant includes but is not limited to pepper, eggplant and tomato, etc.

[0011] Further, the host of the damping-off is Cruciferae plant.

[0012] Still further, the Cruciferae plant includes but is not limited to rape, Chinese cabbage, cabbage and mustard, etc.

[0013] Further, the host of the fusarium wilt is Cucurbitaceae plant.

[0014] Still further, the Cucurbitaceae plant includes but is not limited to cucumber, luffa and balsam-pear, etc.

[0015] In the application, the pathogenic bacteria of the late blight is Phytophthora capsici.

[0016] In particular, the pathogenic bacteria of the damping-off is Rhizoctonia solani.

[0017] Specifically, the pathogenic bacteria of the fusarium wilt is Fusarium oxysporum.

[0018] Specifically, the plant disease is caused by Rhizoctonia solani, Sclerotinia sclerotiorum, Sclerotium hydrophilum, Botrytis cinerea, Monilinia fructicola, Alternaria alternata, Aspergillus flavus, Verticillium dahliae, Magnaporthe oryzae, Verticillium longisporum, Colletotrichum higginsianum, Colletotrichum fructicola, Leptosphaeria biglobosa, Fusarium graminearum and / or Ustilaginoidea virens.

[0019] The present application also provides a preparation for preventing and treating plant diseases, which mainly comprises Actinacidiphila reveromycinica 3-10, spore liquid of Actinacidiphila reveromycinica 3-10, secretion of Actinacidiphila reveromycinica 3-10 or fermentation liquor of Actinacidiphila reveromycinica 3-10.

[0020] The present application also provides a method for preventing and treating plant diseases, which comprises the step of irrigating roots of plants with spore liquid, fermentation liquor or secretion of Actinacidiphila reveromycinica 3-10.

[0021] Further, the concentration of the spore liquid of Actinacidiphila reveromycinica 3-10 is 10 5 spores / mL.

[0022] Specifically, the plant is pepper.

[0023] The pathogenic bacteria of the plant diseases are Phytophthora capsici.

[0024] The present application also provides a method for preventing and treating plant damping-off, which comprises the step of irrigating roots of plants with spore liquid, fermentation liquor or secretion of Actinacidiphila reveromycinica 3-10.

[0025] Specifically, the plant is rape.

[0026] The present application also provides a method for preventing and treating plant damping-off, which comprises the step of irrigating roots of plants with spore liquid, fermentation liquor or secretion of Actinacidiphila reveromycinica 3-10.

[0027] Further, the concentration of the spore liquid of Actinacidiphila reveromycinica 3-10 is 10 7 spores / mL.

[0028] Specifically, the plant is cucumber.

[0029] The beneficial effects of the present application: the present application first discovers that the fermentation broth of Actinacidiphila reveromycinica 3-10 can effectively inhibit the mycelial growth of plant disease pathogens, including Rhizoctonia solani, Sclerotinia sclerotiorum, Sclerotium hydrophilum, Phytophthora capsici, Botrytis cinerea, Monilinia fructicola, Rhizoctonia solani, Alternaria alternata, Fusarium oxysporum, Aspergillus flavus, Verticillium dahliae, Magnaporthe oryzae, Verticillium longisporum, Colletotrichum higginsianum, Colletotrichum fructicola, Leptosphaeria biglobosa, Fusarium graminearum, and Ustilaginoidea virens. In addition, the present application first discovers that the fermentation broth of Actinacidiphila reveromycinica 3-10 can effectively prevent and treat plant diseases, damping-off and fusarium wilt. Among them, the treatment effect and the prevention effect of 3-10 fermentation broth on pepper plants on pepper blight are 58% and 86% respectively; the treatment effect and the prevention effect of 3-10 fermentation broth on rape plants on rape damping-off are 68.61% and 79.07% respectively; the prevention effect of 3-10 fermentation broth on cucumber plants on cucumber fusarium wilt is 100%.

[0030] The Actinacidiphila used in the present application is specifically Actinacidiphila reveromycinica 3-10 strain, which has been preserved in China Center for Type Culture Collection (address: Wuhan University, Wuhan, China, postcode: 430072) on September 27, 2024, and the preservation number is CCTCC NO: M 20242102. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1Figure 1 shows the morphological characteristics and phylogenetic tree of Actinacidiphila reveromycinica 3-10. A: culture morphology (front view) on ISP2 medium cultured for 14 days; B: culture morphology (back view) on ISP2 medium cultured for 14 days; C: single colony morphology on ISP2 medium cultured for 14 days; D: optical microscope observation of spore chains; E: phylogenetic tree of 3-10 based on 16S rDNA sequence.

[0032] Figure 2 Figure 6 shows the results of mycelial growth inhibition of various plant pathogenic fungi by fermentation broth of Actinacidiphila reveromycinica 3-10 (3-7 dpi). The fermentation broth of 3-10 added to PDA plates at a ratio of 1% and 5% has a good inhibitory effect on the mycelial growth of various plant pathogenic fungi relative to the CK control.

[0033] Figure 3The biocontrol effect of Actinacidiphila reveromycinica 3-10 on pepper Phytophthora blight was determined (5 dpi). Compared with the treatment of only inoculating Phytophthora capsici on pepper, the treatment of Actinacidiphila reveromycinica 3-10 fermentation broth before and after the inoculation of Phytophthora capsici on pepper can significantly reduce the leaf shedding and seedling death caused by Phytophthora capsici. The treatment effect and prevention effect of Actinacidiphila reveromycinica 3-10 on pepper Phytophthora blight reached 58% and 86%, respectively.

[0034] Figure 4 The biocontrol effect of Actinacidiphila reveromycinica 3-10 on oilseed rape Rhizoctonia rot was determined (10 dpi). Compared with the treatment of only inoculating Rhizoctonia solani on oilseed rape, the treatment of Actinacidiphila reveromycinica 3-10 fermentation broth before and after the inoculation of Rhizoctonia solani on oilseed rape can significantly reduce the stem base constriction and wilting of the whole plant caused by Rhizoctonia solani. The treatment effect and prevention effect of Actinacidiphila reveromycinica 3-10 on oilseed rape Rhizoctonia rot reached 68.61% and 79.07%, respectively.

[0035] Figure 5 The biocontrol effect of Actinacidiphila reveromycinica 3-10 on cucumber Fusarium wilt was determined (5 dpi). Compared with the treatment of only inoculating Fusarium oxysporum on cucumber, the treatment of Actinacidiphila reveromycinica 3-10 fermentation broth before the inoculation of Fusarium oxysporum on cucumber can significantly reduce the wilting and death of seedlings caused by Fusarium oxysporum. The prevention effect of Actinacidiphila reveromycinica 3-10 on cucumber Fusarium wilt reached 100%. DETAILED DESCRIPTION

[0036] Actinacidiphila reveromycinica 3-10 has not been reported to have a biocontrol effect on plant diseases. The applicant conducted experiments on the function of Actinacidiphila reveromycinica 3-10 in preventing and treating plant diseases, and the results proved that the new strain has a significant prevention and treatment effect on plant diseases.

[0037] In order to better explain the present application, the main content of the present application is further illustrated below in combination with specific examples, but the content of the present application is not limited only to the following examples. The technical solutions involved in the examples of the present application are conventional solutions in the art, unless otherwise specified; the reagents or materials mentioned are from commercial channels, unless otherwise specified.

[0038] Isolation, identification and biological characteristics analysis of Actinacidiphila reveromycinica 3-10

[0039] 1.1 Isolation of strain 3-10

[0040] Rice samples were collected from the field of Huazhong Agricultural University. The roots of rice were washed with tap water and the surface soil was removed. 1 g of root, sheath, leaf and spike of rice were washed with sterile water for three times and then put into a mortar. 10 mL of sterile water containing 0.1% Tween 20 and appropriate amount of quartz sand were added and ground thoroughly. 1 mL of the ground solution was taken and water-bathed at 80°C for 10 min. The ground solution was diluted to 10 times with sterile water and 100 μL of the diluted solution was uniformly spread on PDA plates. The plates were cultured at 28°C under light for 3 days. Single bacterial colonies were picked and transferred to PDA slants. After being cultured at 28°C for 3 days, the slants were stored at 4°C for future use. Single colonies of each strain were co-cultured with Rhizoctonia solani. After primary screening and re-screening, a bacterial strain with significant inhibitory effect on Rhizoctonia solani was obtained and named as 3-10. -6

[0041] 1.2 Morphological characteristics of strain 3-10

[0042] After being cultured on ISP2 medium for 14 days, 3-10 could produce abundant aerial hyphae (A, B). The color of the colony was gray to white. Single colony was in the form of raised dome. The edge of the colony was jagged. No soluble pigment was produced. The center of the colony was wrinkled (C). Under light microscope, the aerial hyphae were branched and developed into linear spore chains. The spore chains were broken to form spores. The spores were short rods (D). Figure 1 Figure 1 Figure 1

[0043] 1.3 Identification of the taxonomic attributes of strain 3-10

[0044] ​​​​Strain 3-10 was inoculated in ISP-2 culture solution and cultured at 150 r / min for 3 days. The mycelium was centrifuged to remove the filtrate, washed with physiological saline twice, and the genomic DNA of 3-10 was extracted by CTAB method (Liu Binghui et al., 2008). Colony PCR was performed using 16S rDNA universal amplification primers (SEQ ID No. 1, 27 F: 5'-AGAGTTTGATCCTGGCTCAG-3'; SEQ ID No. 2, 1492 R: 5'-TACGGCTACCTTGTTACGACTT-3'). The PCR reaction conditions were as follows: 95°C pre-denaturation for 5 min; 95°C denaturation for 1 min, 56°C annealing for 1.5 min, 72°C extension for 30 s, 35 cycles, and 72°C extension for 10 min. The PCR product was detected by 1% agarose gel electrophoresis. The PCR product was recovered and purified using a DNA recovery kit from Axygen. The sequencing results were submitted to the NCBI nucleic acid database for Blast comparison. The 16S rDNA sequences of related actinomycetes (Komaki H., 2024) and an outgroup strain Catenulispora acidiphila DSM44928 were selected. Sequence multiple alignment was performed using MEGA 7.0 software. A phylogenetic tree was constructed using the neighbor-joining method. The classification status of the strain was finally determined.

[0045] The results of constructing the phylogenetic tree showed that strain 3-10 was clustered with Actinacidiphila reveromycinica SN-593. Figure 1 E), combined with the morphological characteristics of 3-10, strain 3-10 was finally identified as Actinacidiphila reveromycinica.

[0046] SEQ ID No. 3 16S rDNA sequence of Actinacidiphila reveromycinica 3-10:

[0047]

[0048] The strain 3-10 was preserved in China Center for Type Culture Collection (address: Wuhan University, Wuhan, China) on September 27, 2024, and the preservation number was CCTCC M 20242102.

[0049] Example 2 Antagonistic activity of Actinacidiphila reveromycinica 3-10 fermentation broth against plant pathogenic fungi

[0050] The 3-10 strain stored in the laboratory was taken out from the -80°C refrigerator, the 3-10 strain was streaked on the ISP-2 solid culture medium for activation, and after 7 days of culture at 28°C, the bacterial body of 3-10 was scraped and washed with sterile water, filtered with three layers of lens paper, and diluted to obtain 3-10 bacterial liquid (10 8 The 3-10 strain was inoculated into PDB culture solution at a ratio of 1% (v / v), and the fermentation was carried out in a 28°C, 180 rpm shaker for 7 days to obtain the 3-10 strain shake culture fermentation broth.

[0051] PDB liquid culture medium preparation (1 L): peeled potato 200 g, glucose 20 g, distilled water 1000 mL, 121°C high temperature sterilization for 30 min, 4°C storage.

[0052] ISP-2 liquid culture medium preparation (1 L): yeast extract powder 4 g, malt extract 10 g, glucose 4 g, distilled water 1000 mL, pH 6.5-7.0, 121°C high temperature sterilization for 30 min, 4°C storage.

[0053] The 3-10 strain PDB fermentation broth was centrifuged at high speed to remove the bacterial bodies (12000 rpm, 15 min), and the sterile fermentation broth was filtered twice with a 0.22 μm bacterial filter, then added to the PDA culture medium at a ratio of 1% and 5% to prepare a toxic plate, and the control was a PDA plate without the addition of 3-10 strain fermentation broth. A 5 mm diameter puncher was used to punch the activated pathogenic fungi (Sclerotinia sclerotiorum, Sclerotium hydrophilum, Phytophthora capsici, Botrytis cinerea, Monilinia fructicola, Rhizoctonia solani, Alternaria alternata, Fusarium oxysporum, Aspergillus flavus, Verticillium dahliae, Magnaporthe oryzae, Verticillium longisporum, Colletotrichum higginsianum, Colletotrichum fructicola, Leptosphaeria biglobosa, Fusarium graminearum, Ustilaginoidea virens) on the PDA culture medium, and inoculated with various plant pathogenic fungi mycelial blocks on different plates, respectively. After incubation at the optimum growth temperature of various pathogenic fungi (20~28°C) for 3~7 d, the lesion diameters were measured and the mycelial inhibition rate of 3-10 to various pathogenic fungi was calculated. Mycelial growth inhibition rate (%) = 100% × (control lesion diameter - treatment lesion diameter) / control lesion diameter.

[0054] The results are as follows Figure 2As shown in Table 1, after 3-7 days of culture, 3-10 fermentation liquor can significantly inhibit the mycelial growth of plant pathogenic fungi, wherein the toxin plate containing 5% 3-10 strain fermentation liquor has a high mycelial growth inhibition rate of 70%-100% on Sclerotinia sclerotiorum, Botrytis cinerea, Fusarium oxysporum, Aspergillus flavus, Leptosphaeria biglobosa, and Colletotrichum higginsianum; a medium mycelial growth inhibition rate of 40%-70% on Phytophthora capsici, Monilinia fructicola, Rhizoctonia solani, Alternaria alternata, Verticillium dahliae, Magnaporthe oryzae, and Colletotrichum fructicola; and a relatively low mycelial growth inhibition rate of 25-40% on Sclerotium hydrophilum, Verticillium longisporum, Fusarium graminearum, and Ustilaginoidea virens.

[0055] Table 1. Results of mycelial growth inhibition rate of 3-10 fermentation liquor on plant pathogenic fungi (3-7 dpi)

[0056]

[0057] Example 3. In vivo efficacy test of Actinacidiphila reveromycinica 3-10 fermentation liquor on pepper late blight

[0058] One-month-old pepper seedlings were transplanted into plastic pots filled with culture soil (nutrient soil: substrate soil: vermiculite = 8:4:1) and incubated in the dark for 7 days before being used in the experiment. Preparation of P. capsici spore suspension: P. capsici mycelia from a PDA plate were added to 15 mL of 10% V8 culture solution and incubated at 25 °C in the dark for 3 days. The culture solution was discarded and 10 mL of sterile water was added to cover the mycelium, and the incubation was continued. The sterile water was changed every 12 hours for a total of 3 times. The spores were released by alternating cold and hot stimulation at 4 °C for 15 minutes and 25 °C for 15 minutes. The spore suspension was diluted to 10 5 spores / mL with sterile water for use.

[0059] The experiment was divided into 5 treatments, all of which were treated by wounding the base of the pepper stem:

[0060] 1, 3-10 treatment: the pepper was only irrigated with 3 mL of 3-10 fermentation broth; 2, sterile water (CK) treatment: the pepper was only irrigated with 3 mL of sterile water; 3, P. capsici treatment: the pepper was only irrigated with 3 mL of P. capsici spore suspension; 4, prophylactic treatment: the pepper was irrigated with 3 mL of 3-10 fermentation broth 24 hours before being inoculated with 3 mL of P. capsici spore suspension; 5, treatment: the pepper was inoculated with 3 mL of P. capsici spore suspension 24 hours before being inoculated with 3 mL of 3-10 fermentation broth.

[0061] Each group had 10 replicates, and the disease incidence was investigated and the disease index was calculated 5 days after inoculation, and the seedling mortality rate was investigated 10 days after inoculation. The disease index of pepper blight was graded according to the grading standard of Zhang et al. (2010):

[0062] 0 grade: no obvious symptoms;

[0063] 1 grade: a small amount of brown lesions appeared on the base of the seedling stem;

[0064] 2 grade: the stem lesions spread to the heart leaves or the lesions surrounded the entire stem, and the plants were slightly prostrate;

[0065] 3 grade: the plants were prostrate, and most of the leaves were obviously wilted or yellowed;

[0066] 4 grade: the plants were prostrate, and the whole plant was wilted;

[0067] 5 grade: the whole plant was dead.

[0068] Disease index = ∑ number of plants at each grade x ∑ representative value at each grade / (total number of plants surveyed x representative value of the highest grade) x 100;

[0069] Control effect (%) = (disease index of control group - disease index of treatment group / disease index of control group) x 100%.

[0070] Results are shown in Table 2 and Figure 1. Figure 3 As shown in Table 2 and Figure 1, the treatment of Actinacidiphila reveromycinica 3-10 alone had no adverse effect on the pepper itself. Compared with the treatment of inoculating the pepper with Phytophthora capsici spore suspension alone, Actinacidiphila reveromycinica 3-10 had a significant control effect on pepper blight. Five days after inoculation with Phytophthora capsici, the preventive effect and therapeutic effect of Actinacidiphila reveromycinica 3-10 on pepper blight reached 86% and 58%, respectively. Ten days after inoculation with Phytophthora capsici, the seedling mortality rate of the pepper inoculated with Phytophthora capsici alone was 100%, while the seedling mortality rate of the pepper treated with Actinacidiphila reveromycinica 3-10 for blight prevention and treatment was only 40% and 10%, respectively.

[0071] Table 2. Control effect of 3-10 fermentation broth on pepper blight (5 dpi)

[0072] Example 4. In vivo control effect of Actinacidiphila reveromycinica 3-10 on oilseed rape damping-off

[0073] The oilseed rape seeds were sterilized, and the sterilization process was as follows: 75% alcohol sterilization for 3 min, 5% sodium hypochlorite sterilization for 3 min, and sterile water rinsing for 3 times. The sterilized oilseed rape seeds were placed in sterile glass culture dishes lined with sterile filter paper, and an appropriate amount of sterile water was added to wet the filter paper. The seeds were then incubated at 20 °C in a culture room for 5 days. After the oilseed rape seeds germinated, healthy seedlings were selected and transplanted into plastic pots. After 14 days of culture under the conditions of 24 °C, 16 h light / 8 h darkness in a greenhouse, the inoculation test was performed. The newly activated growth of Rhizoctonia solani for 3 days was punched with a puncher (d = 9 mm), and the fungus cake was inoculated into PDB medium (100 mL in a 250 mL bottle). Five fungus cakes were inoculated into each bottle, and the mycelium was grown to a certain amount at 25 °C, 120 rpm in the dark for 3 days. The mycelium was filtered with sterile gauze, naturally dried, and then 2 g of the mycelium was added to 200 mL of sterile water to make a fungus suspension with a bean milk machine. The fungus suspension was used as a reserve.

[0074] The test was divided into 5 treatments:

[0075] 1, 3-10 treatment: rapeseed was only irrigated with 3 mL 3-10 fermentation liquor; 2, sterile water (CK) treatment: rapeseed was only irrigated with 3 mL sterile water; 3, Rhizoctonia solani treatment: rapeseed was only irrigated with 3 mL Rhizoctonia solani suspension; 4, prevention treatment: rapeseed was irrigated with 3 mL 3-10 fermentation liquor 24 h before and then irrigated with 3 mL Rhizoctonia solani suspension; 5, treatment treatment: rapeseed was irrigated with 3 mL Rhizoctonia solani suspension 24 h before and then irrigated with 3 mL 3-10 fermentation liquor.

[0076] All treatments were placed at 24 °C, 16 h light / 8 h dark conditions, 10 replicates were set in each group, the disease incidence was investigated and the disease index was calculated after 10 d of inoculation, and the seedling mortality rate was investigated after 15 d. The disease grading standard of rapeseed Rhizoctonia solani disease was set according to the disease grading standard of cotton Rhizoctonia solani disease (Hao YJ et al., 2005):

[0077] 0 level: the plant has no any disease;

[0078] 1 level: the plant stem lesion needle size to around the stem 1 / 4;

[0079] 3 level: lesion around the stem 1 / 4-1 / 2;

[0080] 5 level: lesion around the stem 1 / 2-3 / 4;

[0081] 7 level: lesion around the stem lodging or dead.

[0082] Disease index = ∑ level of disease incidence × ∑ level of representative value / (total number of plants surveyed × highest level of representative value) × 100;

[0083] Control effect (%) = (control group disease index - treatment group disease index / control group disease index) × 100%.

[0084] The results are shown in Figure 4 and Table 3, only inoculating Actinomyces acidophilus 3-10 treatment has no any adverse effects on rapeseed itself. Relative to only inoculating Rhizoctonia solani suspension treatment, Actinomyces acidophilus 3-10 has a significant control effect on rapeseed Rhizoctonia solani disease, after 10 d of inoculating Rhizoctonia solani suspension, the prevention effect and treatment effect of Actinomyces acidophilus 3-10 on rapeseed Rhizoctonia solani disease reached 79.07% and 68.61% respectively. After 15 d of inoculating Rhizoctonia solani suspension, the seedling mortality rate of rapeseed inoculated with only Rhizoctonia solani suspension was 100%, while the seedling mortality rate of rapeseed treated by Actinomyces acidophilus 3-10 for Rhizoctonia solani disease treatment and prevention was 0%.

[0085] Table 3. Control effect of 3-10 fermentation liquor on rapeseed Rhizoctonia solani disease (10 dpi)

[0086] Example 5 Biocontrol efficacy of Actinacidiphila reveromycinica 3-10 against cucumber fusarium wilt

[0087] Cucumber seeds were sterilized, the sterilization process was as follows: 75% alcohol sterilization for 3 min, 5% sodium hypochlorite sterilization for 3 min, and sterile water rinsing for 3 times. The sterilized cucumber seeds were placed in sterile glass culture dishes lined with sterile filter paper pieces, and the filter paper pieces were soaked with an appropriate amount of sterile water. The seeds were incubated at 20 °C for 7 days. After the seeds germinated, healthy seedlings were selected and transplanted into plastic pots. After 14 days of culture under the conditions of 24 °C, 16 h light / 8 h dark, the seedlings were inoculated.

[0088] Fusarium oxysporum spore solution was obtained as follows: Fusarium oxysporum grown on PDA plates for 7 days was punched into PDB culture solution (100 mL in a 250 mL bottle) with a 5 mm diameter punch, 5 fungal cakes were inoculated into each bottle, and the culture was incubated at 25 °C, 120 rpm in the dark for 7 days. The mycelium was filtered with three layers of sterile lens paper to obtain the spore solution, which was diluted to 10 7 individuals / mL for later use.

[0089] The experiment was divided into 4 treatments:

[0090] 1. 3-10 treatment: cucumber roots were soaked in 3-10 fermentation broth for 5 min before transplanting into plastic pots; 2. sterile water (CK) treatment: cucumber roots were soaked in sterile water for 5 min before transplanting into plastic pots; 3. Fusarium oxysporum treatment: cucumber roots were soaked in Fusarium oxysporum spore solution for 5 min before transplanting into plastic pots; 4. 3-10 treatment for Fusarium oxysporum: cucumber roots were soaked in Fusarium oxysporum spore solution for 5 min before transplanting into plastic pots, and 3 mL of 3-10 fermentation broth was poured into the root of each cucumber after transplanting.

[0091] All treatments were incubated under the conditions of 24 °C, 16 h light / 8 h dark, with 5 replicates in each group. The disease incidence was investigated and the disease index was calculated 5 days after inoculation, and the mortality rate was investigated 10 days after inoculation. The disease grading standard was based on the Fusarium wilt disease grading standard for oilseed rape seedlings (Fang Zhongda, 1998).

[0092] 0 grade: no symptoms;

[0093] 1 grade: true leaves, cotyledon yellowing or wilting area not more than 50% of total leaf area;

[0094] 2 grade: true leaves, cotyledon yellowing or wilting area more than 50% of total leaf area;

[0095] Grade 3: Leaves are wilted or dead, only the growing point survives;

[0096] Level 4: The entire plant has died.

[0097] Disease index = ∑ number of diseased plants at each level × ∑ representative value at each level / (total number of plants surveyed × highest level representative value) × 100;

[0098] Prevention and control effect (%) = (disease index of control group - disease index of treatment group / disease index of control group) × 100%.

[0099] The results are as follows Figure 5 As shown in Table 4, inoculation with only *Acidophilus actinomycete* 3-10 had no adverse effects on cucumbers. Compared to inoculation with only *Fusarium oxysporum* spores, *Acidophilus actinomycete* 3-10 showed a significant control effect against cucumber wilt. Five days after inoculation with *Fusarium oxysporum* spores, the control effect of *Acidophilus actinomycete* 3-10 against cucumber wilt reached 100%. Fifteen days after inoculation with *Fusarium oxysporum* suspension, the seedling mortality rate of cucumbers inoculated only with *Fusarium oxysporum* spores was 100%, while the seedling mortality rate after control with *Acidophilus actinomycete* 3-10 was 0%.

[0100] Table 4. Control effect of fermentation broth 3-10 on cucumber wilt (5 dpi)

Claims

1. Acidophilic Actinomycetes Actinacidiphila reveromycinica 3-10, its accession number is CCTCC NO:M20242102.

2. The acidophilic actinomycete according to claim 1 Actinacidiphila reveromycinica The application of 3-10 in the prevention and control of plant diseases is characterized by: The plant diseases mentioned are blight, damping-off, and / or wilt; the plant diseases mentioned are caused by *Rhizoctonia solani*, *Sclerotinia sclerotiorum*, *Sclerotinia hydrophila*, *Botrytis cinerea*, *Alternaria alternata*, *Aspergillus flavus*, *Verticillium dahliae*, *Bacillus oryzae*, *Verticillium longiflorum*, *Colletotrichum higgins*, *Anthracnose fungus*, *Black shank fungus* of rapeseed, *Fusarium graminearum*, *Aspergillus oryzae*, *Phytophthora capsici*, *Rhizoctonia solani*, and / or *Fusarium oxysporum*.

3. The application according to claim 2, characterized in that: The host of the disease is a plant of the Solanaceae family; the Solanaceae family includes pepper, eggplant, or tomato.

4. The application according to claim 2, characterized in that: The host of damping-off disease is a cruciferous plant; the cruciferous plant is rapeseed, bok choy, cabbage or mustard.

5. The application according to claim 2, characterized in that: The host of the wilt disease is a cucurbitaceous plant; the cucurbitaceous plant is cucumber, loofah or bitter melon.

6. A preparation for controlling plant diseases, characterized in that: Its main component is the acidophilic actinomycete described in claim 1. Actinacidiphila reveromycinica 3-10. Acidophilic Actinomycetes Actinacidiphila reveromycinica 3-10 spores or acidophilic actinomycetes Actinacidiphila reveromycinica Fermentation broth of 3-10.

7. A method for preventing and controlling plant diseases, characterized in that: The steps include: using the acidophilic actinomycetes described in claim 1 Actinacidiphila reveromycinica Plants can be irrigated with spore liquid or fermentation liquid at concentrations of 3-10. Specifically, the plant in question is a chili pepper; The pathogen of the disease is Phytophthora capsici (Phytophthora capsici). Phytophthora capsici ).

8. A method for preventing and controlling plant damping-off, characterized in that: The steps include: using the acidophilic actinomycetes described in claim 1 Actinacidiphila reveromycinica Plants can be irrigated with spore liquid or fermentation liquid at concentrations of 3-10. Specifically, the plant in question is rapeseed.

9. A method for controlling plant wilt disease, characterized in that: The steps include: using the acidophilic actinomycetes described in claim 1 Actinacidiphila reveromycinica Plants can be irrigated with spore liquid or fermentation liquid at concentrations of 3-10. Specifically, the plant in question is a cucumber.

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