葡萄霜霉病拮抗细菌N22的筛选鉴定及其防效初探

Preliminary report on screening and identification of antagonistic bacterium N22 against grape downy mildew and its controlling efficiency

采用叶盘法筛选到1株防治葡萄霜霉病效果较好的芽孢杆菌N22菌株,并对该菌株进行了鉴定。结果表明,用N22菌株的16S r DNA序列与其相关种属进行比对,其序列与解淀粉芽孢杆菌（Bacillus amyloliquefaciens）及枯草芽孢杆菌（Bacillus subtilis）都具有100%的相似性。系统发育分析也表明,N22菌株和枯草芽孢杆菌及解淀粉芽孢杆菌聚在一个枝上。经进一步克隆了该菌株的gyr A基因序列,其比对结果中相似度高的菌株中只出现了解淀粉芽孢杆菌,其Query cover达到91%。因此,该菌株最终鉴定为解淀粉芽孢杆菌。以解淀粉芽孢杆菌N22菌株的田间防效显示,当发酵液菌体孢子含量为10~7个/m L的防治效果最好,防效可达76.94%。

Bacillus N22 strains with better controlling efficiency against grape downy mildew were selected and identified by method of leaf disc. The 16S rDNA sequence of N22 was cloned and compared with those of related species. The resuits showed that it was 100% the same as the sequence of Bacillus amyloliquefaciens and Bacillus subtilis. Based on phylogenetic analysis, N22 strain was clustered with B. subtilis and B. amyloliquefaciens in one branch. The gyrA gene sequence of N22 strain was cloned and compared with its related species, and only B. amyloliquefaciens with cover Query of 91% was found in the strains with high similarity, from which it could be concluded that the strain was B. amyloliquefaciens. Results of its field controlling experiment showed that best controlling efficiency reached 76.94% at 107/ml spore concentration of fermentation liquid.