| Eggplant(Solarium melongena L.)is an important vegetable crop in the world,one of the most popular vegetable products,while China is the world's largest producer and consumer of eggplant.The planting areas of eggplant plants are more than 400,000 mu in Zhejiang province.However,in recent years,Verticillium wilt of eggplant occurred seriously in some regions of zhejiang province,influencing seriously the development of eggplant industry.To control the disease effectively,it was investigated systematically,pathotype and physiological races of its pathogen were identified as well as biological control of disease and action mechanisms were studied as well.In addition,the occurrence and severity of verticillium wilt was related closely to the number of microsclerotia in soil.While quantitative density of microsclerotia in soil is a basis of prediction and forecast for disease control.However,the existing methods for detecting microsclerotia is not perfect.Therefore,in this study,a new technology for detection of microsclerotia in soil was established.The main research results are as follows:1.Study on pathogenic differentiation and biological control against Verticillium wilt of eggplantDisease observation and pathogenicity tests indicated that Verticillium wilt of eggplant in plastic greenhouse occurred usually in mid-January and it was caused by Verticillium dahliae Kleb.Identical results of pathotype and physiological races of pathogen with the representative strains demonstrated that seven isolates isolated from Zhejiang province all belonged to the defoliation pathotype and physiological race 2,respectively.In vitro experiments showed that the strain ShX301 had a highest inhibitory activity against hypha growth and conidial germination of pathogen isolated the diseased eggplant plants among five Paenibacillus polymyxa strains.The in vivo experiments for controlling Verticillium wilt of eggplant and plant growth promotion displayed that strain ShX301 had a highest inhibitory activity against controlling the disease and plant growth promotion.Inoculation by strain ShX301 reduced disease incidence and severity by 30%and 20.02%,respectively,and promoted eggplant plant growth enhancing above ground seedling stem length and biomass by 59.24%and 69.41%as well as underground biomass by 54.11%,respectively.The determination of volatile metabolites showed that five strains of P.polymyxa were able to produced volatile metabolites,which inhibited hypha growth of pathogen but there was no significant difference among strains.MALDI-TOF-MS analysis revealed that the Fusaricidins were main activity compounds of antagonistic pathogen.Therefore,this study provides the scientific theory basis for development of the strain ShX301 using as biocontrol or plant growth promotion agent.2.Preparation of specific antigen for detecting soil microsclerotia of Verticillium dahliaeSurface proteins of hyphae and microsclerotia of defoliating pathotype strains 086 and nondefoliatin gpathotype strains BP2 were labeled by biotin and they were isolated by Streptavidin Agarose Resin 6FF kit.After freeze drying,concentration,desalting,enzymatic digestion and serial treatment,the proteins obtained was analyzed by mass spectrometry based on strains 086 and BP2 genomes.Analysis results showed the number of microsclerotial surface proteins of strains 086 and BP2 was 286 and 266,respectively after removing their mycelial surface proteins.Two strain-specific genes and one non-specific gene were obtained by protein homology analysis.Base on analysis of secondary structure,transmembrane prediction,signal peptide prediction,antigen-determining cluster prediction and the prediction of O-and N-inked glycoprotein with polysaccharides,three 14-28 AA peptides were selected for using as artificial synthesis of antigens.Antiserum was obtained by immunizing rabbit with the antigen-conjugated carrier protein,and the isolated antibody was coated with immunomagnetic beads for the detection of microsclerotia. |
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