抗农作物病原真菌的Streptomyces sp.ⅡR21菌株分离及其克拉维烷基因簇分析

Isolation of Streptomyces sp.ⅡR21 strain resistant to crop pathogenic fungi and analysis of the clavam biosynthetic gene clusters

从神农架烟草种植地土壤中分离出1株对7株农作物病原真菌具有抗性活性菌株,命名为ⅡR21菌株。采用琼脂块法测定,该菌株对稻瘟病菌、立枯丝核病菌、腐霉病菌、禾谷镰刀病菌和黄色镰刀病菌具有较强的抑菌活性。对该菌株的生理生化特性和16SrRNA基因序列同源性比对,初步鉴定ⅡR21菌株属于链霉菌属。经过有机溶剂萃取、硅胶柱层析、薄层层析和制备型高效液相色谱对ⅡR21菌株发酵液进行分离纯化,获得了1个纯度为90.34%的具有抗稻瘟病菌168菌株活性的化合物单体。采用高通量测序技术对ⅡR21菌株进行全基因组测序,通过全基因组序列分析,ⅡR21菌株基因组中包含克拉维烷的合成基因簇,并推测出克拉维烷的合成代谢途径。

A bacterial strain with antifungal activity against seven crop pathogenic fungi was isolated from soil and named as ⅡR21.The ⅡR21 strain was detected through agar block method and the results indicated that the ⅡR21 strain exhibited much stronger antifungal activity against Magnaporthe grisea,Rhizoctonia solani,Botrytis cinerea,Fusarium aminearum and Fusarium culmorum.The ⅡR21 strain was identified as Streptomyces through physiological and biochemical characteristics and alignment analysis of the 16 SrRNA gene sequence.The fermentation broth of the ⅡR21 strain was separated and purificated by extraction,silica gel column chromatography and preparative high performance liquid chromatography,and a compound with a purity of 90.34% with activity against the Magnaporthe grisea 168 strain was obtained.The Streptomyces sp.ⅡR21 genome was sequenced using high throughput sequencing technology,and analyzed by bioinformatics tools.The result suggested that the ⅡR21 strain contained the gene cluster of clavams,and the metabolic pathway for clavam biosynthesis was proposed.