In order to screen effective antagonistic agents toPhytophthora melonis, 269 strains were isolated from collected soil in Hunan and Beijing with gradient dilution method. 2 strains showed obvious antagonistic effects toPhytophthora melonis by using agar plate dual culture, and strain X54 and strain P3 were finally screened out. The diluted 5 times filtration showed their inhibition rates were over 70%. Through observation of culture morphological characteristics, physiological and biochemical experiment, and molecular identification of 16S rDNA, we found that actinomycete X54 wasStreptomyces virginiae and bacterial P3 wasBacillus licheniformis.%为了筛选对黄瓜疫霉菌有抑制作用的生防菌，采用土壤稀释法从湖南、北京等地采集的土壤样品中分离到269株放线菌和细菌，以黄瓜疫霉菌为靶标菌，通过平板对峙培养法，筛选出2株对黄瓜疫霉菌有明显拮抗作用的生防菌株。采用5倍稀释发酵液对黄瓜疫霉菌进行抑菌活性检测，放线菌X54和细菌P3的抑制率达到70%以上。通过培养形态特征观察、生理生化试验及16S rDNA分子鉴定，放线菌X54为弗吉尼亚链霉菌（Streptomyces virginiae），细菌P3为地衣芽孢杆菌（Bacillus licheniformis）。
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