Screening,Identification and Bacteriostat Qualitative Analysis of Antagonistic Strain against Colletotrichum gloeosporioides

L Jitao;WEI Li;CAO Xiaolu;YANG Jiye;GUO Xiaojun;LI Lubin;YIN Yanjun;College of Life Science,Agriculture University of Hebei;Environmental Monitoring Center of Handan;State Key Laboratory of Tree Genetics and Breeding,Research Institute of Forestry,Chinese Academy of Forestry;

cymbidium anthracnose;;Colletotrichum gloeosporioides;;Bacillus;;antagonism;;screening;;identification;;antibacterial substance

Twenty-three strains were obtained by screening strains with high antagonism against Colletotrichum gloeosporioides by the tablet confrontation method from 126 strains,which were isolated from Xinjiang Kumtag desert samples. Strain N147-1-3 with highest antagonism was obtained by using the plate diffusion method. Combined with the morphology observation of colonies and cells,16 S r DNA sequence analysis,physiological and biochemical characteristics tests,the strain was finally identified as Bacillus methylotrophicus. The test results of the supernatant of the strain fermented liquid showed that the sediment by adding 60% ammonium sulfate had the highest antibacterial activity. The supernatant of the strain fermented liquid lost its antimicrobial activity after the chloroform extraction. The antagonism effect of the strain disappeared after treatments by high temperatures or proteinase K. The antibacterial substance was finally identified as protein.