黄瓜蔓枯病拮抗细菌的分离与筛选

以黄瓜蔓枯菌(Ascochyta citrullina)为指示菌,采用平板稀释法和对峙法对48份土样进行分离筛选得到拮抗细菌53株,发现菌株G8、Sh34拮抗谱宽,对黄瓜蔓枯菌和菌核抑制效果均超过76%,且能分泌几丁质酶。温室接种防病试验结果表明,两菌株发酵液对黄瓜蔓枯病菌防治效果分别达62.5%和51.0%。根据对两菌株形态特征、生理生化特性及16SrDNA序列分析,均被鉴定为枯草芽孢杆菌(Bacillus subtilis)。

Selection of Antagonistic Bacteria for Suppression of Cucumber Gummy Stem Blight Disease

Using dual culture method and dilution separating methods,53 strains of antagonistic bacteria on Ascochyta citrullina were obtained in 48 soil samples.Among the tested bacterial strains,only strains G8 and Sh34 showed strong and stable antagonistic activities against A.citrullina.in the present test,strains G8 and Sh34 inhibited the growth of ten plant pathogenic fungi.The extent of inhibition of A.citrullina and Sclerotinia scleotiorum reached over 76%.The two strains were shown to produce chitinase.Pot trials in greenhouse showed that effects of the fermentated broth of G8 and Sh34 strains against cucumber gummy stem blight disease reached 62.5% and 51.0%,respectively.On the basis of their morphological and biochemical characteristics as well as analysis of the partial sequence of their 16SrDNA,G8 and Sh34 were identified as Bacillus subtilis strains.