烟草黑胫病菌拮抗放线菌LY18的分离筛选与鉴定

Isolation and Identification of Antagonistic Actinomyces LY18 Against Phytophthora parasitica var. nicotianae

为了寻找对烟草黑胫病具有生防潜力的放线菌,笔者采用平板对峙法,从烟草黑胫病发病烟田健株根际土壤中,分离得到1株对烟草黑胫病菌具有显著拮抗效果的放线菌株LY18,其发酵液的无菌滤液对烟草黑胫病菌菌丝的抑制率达70%以上。电镜观察发现,抑菌圈周围的烟草黑胫病菌丝破裂、瘪陷。通过对LY18的形态观察、培养性状观察、生理生化测定结合16S rDNA序列分析,将该菌株鉴定为Streptomyces rajshahiensis。

In order to screen antagonists against Phytophthora parasitica var. nicotianae, the plate-confrontation method was involved. Actinomycetes strain LY18 isolated from soil samples around healthy tobacco individuals＇ roots in tobacco field which broke out tobacco black shank, showed well inhibitory activity to Phytophthora parasitica var. nicotianae. The aseptic filtrate of LY18 mixed into medium plate showed an inhibitory rate of 70% against the mycelial growth of Phytophthora paraMtica var. nicotianae. The SEM observation showed that the mycelium of Phytophthora parasitica var. nicotianae in plate added with aseptic filtrate of LY 18 was dissolution. The LY18 was identified as Streptomyces rajshahiensis according to its morphology, culture characteristic, chemotaxonomic tests and 16S rDNA analysis.