芽孢杆菌LL17的分离鉴定及其对仓储烟叶霉变菌的抑制效果

Isolation and identification of Bacillus LL17 and its inhibition effects on mildew fungi of stored tobacco

为有效控制仓储烟叶的霉变,从烟草根际土壤中分离筛选出1株芽孢杆菌LL17,采用平板对峙法和牛津杯扩散法研究其对3株储烟霉变菌的拮抗效果,并结合培养特征、形态特征、生化特征和16S r DNA基因序列分析对菌株LL17进行了分类学鉴定。结果显示,LL17菌株在分类学上属枯草芽孢杆菌(Bacillus subtilis)。在平板对峙法和牛津杯扩散法的培养平板上均观察到明显的抑菌区,表明LL17菌株对供试的3株仓储烟叶霉变菌具有较强的拮抗作用。且LL17菌株无菌滤液对供试的2株曲霉分生孢子有明显的拮抗作用,可影响孢子萌发或导致菌丝畸变。因此,菌株LL17在储烟霉变的生物防控中可能具有潜在的应用前景和价值。

To effectively control the mildew of stored tobacco leaf, a Bacillus strain LL17 was isolated from tobacco rhizosphere soil. A dual culture method and Oxford cup method were used to study the antagonistic effects of strain LL17 on three kinds of mildew fungi. The bacteria cultural, morphological and biochemical features were observed, and in addition 16S rDNA sequence analysis was used to identify the strain. The results showed that strain LL17 was identified as Bacillus subtilis on the taxonomy. The inhibition zones were clearly observed in PDA by using the dual culture method and Oxford cup method, indicated that strain LL17 was strongly antagonistic towards three kinds of mildew fungi. Sterile filtrate of strain LL17 was antagonistic towards 2 kinds of Aspergillus conidiospores. The sterile filtrate could affect spore germination or induce hyphae deformation. Therefore, strain LL17 might have the potential application prospect and value in biological control of tobacco mildew during storage.