棉花枯萎病拮抗放线菌K5的分离与鉴定

Isolation and Identification of Actinomyces K5 Antagonistic against Fusarium oxysporum f.sp.vasinfectum

从扬州地区土壤中分离到207株放线菌,以棉花枯萎病菌为目标菌,采用抑菌带法测定,筛选到9株有拮抗活性菌株,占所分离总数的4.3%。其中K5对棉花枯萎病菌的拮抗作用最强,抑菌带宽为8mm,同时对其它病菌也有一定的拮抗作用。盆栽试验结果表明菌株K5对棉花枯萎病防治效果达46.5%,与多菌灵相当。通过对菌株K5的形态观察、培养特征、生理生化反应和16S rDNA测定,将其鉴定为玫瑰产色链霉菌Streptomyces roseochromogenus。

Totally 207 actinomyces strains were isolated from soils in Yangzhou. In vitro tests revealed that 9 strains （4.3 % of total isolates） showed antagonistic activities against Fusarium oxysporum f. sp. vasinfectum. Among them, strain K5 exhibited the strongest antibiosis capacity with an inhibitory zone of 8 mm against,mycelial growth of F. oxysporum f. sp. vasinfectum. The control efficiency of K5 on cotton fusarium wilt was 46.5 %, which resembled to that of chemical fungicide carbendazim. K5 was iden- tified as Streptomyces roseochromogenus according to its 16S rDNA sequence analysis, and the morphological, physiological and biochemical characteristics.