The Isolation, Identification And Verification Of Pathogen In Grape Replant Soil

The rapid increase of harmful bacteria in the soil is the main cause of replant disease.In order to explore the main harmful bacteria that cause grape replanting disease,replanting soils of different regions were used as the research object,using traditional dilution plate method and high-throughput sequencing technology to explore the effects of replanting on the population structure of bacteria and fungi in rhizosphere soil of grape;The dominant bacteria and fungi in the replanting soil of different regions were isolated and identified.The pathogenicity of the main dominant fungi was further verified by pot experiment.The main test results were as follows:1.The dominant bacteria and fungi in the grape replanting soil were isolated and identified.Through the combination of traditional plate method and molecular biology method,43 dominant bacteria were identified in the soils of four replanting gardens in Shenyang,Xiongyue and Jinzhou.They belong to 7 genera,named Pseudomonas sp.,Bacillus sp.,Arthrobacter sp.,Micrococcus sp.,Microbacterium sp.,Cellulosimicrobium sp.,Ensifer sp.,where Pseudomonas sp.was the most abundant,followed by Bacillus sp..42 dominant fungi were identified,belonging to 11 genera,named Sporothrix sp.,Clonostachys rosea,Mucor sp.,Trichoderma sp.,Cladosporium sp.,Fusarium sp.,Alternaria sp.,uncultured zygomycete,Stagonosporopsis sp.,Mortierella sp.2.Replanting changed the population structure of soil bacteria and fungi.A total of 13 different genus bacteria were identified by 16 S r DNA sequencing.Compared with the control,the contents of Pedobacter,Bacillus,Rhodoplanes,Devosia,Pseudomonas,and Steroidobacter were significantly increased;Opitutus were significantly decreased;Flavobacterium,Chryseobacterium,Phyllobacterium and Kaistobacter were significantly increased in replanting soil(except XY).A total of 12 different genus fungi were identified by 18 S r DNA sequencing,and the contents of Cladosporium,Mrakiaceae(except XY)and Xanthomendoza(except XY)were significantly increased in replanting soil;Alternaria was significantly increased in BZ continuous soil;Fusarium was significantly increased in SY continuous soil;The content of Chaetomium,Didymella and Coniochaeta was significantly lower than that of the control.3.The pathogenicity of the three dominant fungi was verified.The pathogenicity of three dominant fungi of Alternaria tenuissima,Cladosporium perangustum and Fusarium solani was verified.After the three strains were inoculated to potted soil,the leaves of the V.riparia×V.labrusca cv.Beta were susceptible to the disease,and the death occurred on the 12 th day after inoculation,and the pathogenicity was significant.4.The absolute content of three dominant fungi in replanting soil was determined.The results showed that the absolute content of Alternaria in BZ replanting soil was significantly higher than that in blank soil;The absolute content of Cladosporium in replanting soilwas significantly increased(except BD);The absolute content of Fusarium in the replanting soil was significantly higher than that in the blank soil.