Identification And Measurement Of Actility Of Antagonistic Microbes To Colletotrichum Capsici

Colletotrichum caused plant anthrax widespreadly and serious harmly. C. capsici is one of the important species of this genus. It has mainly harmful on fruits and leaves that has a serious impact on agricultural and forestry production. Bacillus spp.can induce plants to produce disease-resistant substances that widely used in the prevention of Colletotrichum capsici.The isolate identification, mechanism of inhibition, culture condition and isolation of antifungal protein of strain were systematically studied. The results were as follows:1. Screening 4 spore germination inhibition biocontrol strains(B7, B20, B22, B23)and 8 appressorium formation inhibition biocontrol strains(B1, B2, B3, B4, B10, B11, B17,B18) from the early 22 strains obtained by slide culture method. On the basis of morphological and molecular characteristics, the biocontrol strains B1, B2, B3, B4, B7, B10,B11, B17, B18 was identified as Bacillus subtilis.Strains B20, B22, B23 have a high homology with Bacillus amyloliquefaciens, these taxonomic status needs to be further identified.2. The results of dual culture showed that inhibition of spore germination and appressorium formation biocontrol strains have obvious inhibitory effects on the growth of several important fungal pathogens including C. capsici, M. grisea, Diaporthe phaseolorum or Phomopsis asparagi etc. The antibacterial rate reached more than 50%.3. Saturation of ammonium sulfate precipitation method is used in separation active protein of fermentation broth of the spore germination inhibition biocontrol strain components,bioassay results showed that four strains of the crude antifungal protein can be100% inhibition on spore germination of C. capsici.The crude antifungal protein was purified by the Sephadex G-75 gel filtration chromatography and measuring the biological activity of the protein purified by slide culture method.It can be found that first peak of strain B7 was completely inhibited on spore germination of C. capsic. Collected samples ofremaining peak period does not influence spore germination and mycelial growth, but inhibit appressorium.20%-30%, 30%-40%, 40-70% Saturation of ammonium sulfate fractionation precipitation method is used in separation active protein of fermentation broth of the appressorium formation inhibition biocontrol strain components,bioassay results showed that eight strains of the crude antifungal protein can be 100% inhibition on appressorium formation of C. capsici. The crude antifungal protein was purified by the Sephadex G-75 gel filtration chromatography and measuring the biological activity of the protein purified by slide culture method. It can be found that 20% antigungal protein was the best on appressorium formation inhibition.