微白黄链霉菌对红豆草壳二孢的拮抗效果评价

红豆草壳二孢叶斑黑茎病(Ascochyta onobrychidis)是红豆草(Onobrychis viciaefolia)最重要的病害之一,在分离此病菌的同时得到一种对此病菌具有较强抑制作用的微生物,为评价此拮抗菌的开发利用前景,本研究采用形态学、分子生物学和生物化学方法鉴定了其分类地位,并测定了其对红豆草壳二孢的抑菌效果。通过构建系统发育树并结合其形态特征和生理生化特性,将该拮抗菌鉴定为微白黄链霉菌(Streptomyces albidoflavu),在高氏一号培养基上菌落为黄白色,可产生黄白色水溶性色素,孢子丝钩状,顶端螺旋形;在平板对峙试验中该菌的菌落对红豆草壳二孢菌落的相对抑制率达74.33%,同时该菌发酵液对红豆草壳二孢菌丝生长和孢子萌发的抑制率分别为80.95%和93.87%。该菌具有生物防治红豆草壳二孢的开发和利用价值。

Evaluation of the antagonistic effect of Streptomyces albidoflavus against Ascochyta onobrychis

Ascochyta onobrychis is the causal pathogenic microorganism of sainfoin leaf spot and black stem, which is a serious disease.A strain of microorganism that has strong antagonistic activity against A.onobrychis was obtained when the pathogen was isolated.To evaluate the exploitation and foreground of the antagonistic microorganism,the present study identified the taxonomic position of the strain by morphological,molecular, and biochemical methods,as well as determined the inhibitory effect of the strain against A.onobrychis.Based on its morphological characteristics,both physiological and biochemical,together with 16S rDNA sequence analysis,the strain was identified as Streptomyces albidoflavus.The colonies ware yellowish white in color on Gause's agar and produced yellowish white water-soluble pigments and a mycelium hook-like top spiral.The relative inhibition rate to the pathogen was 74.33% that was measured with the dural culture method.The acti-nomycetes sterile fermentation broth had a strong effect on mycelial growth and spore germination,with inhibi-tory rates of 80.95% and 93.87%,respectively.The results showed that the actinomycetes had potential value in the biological control of A.onobrychis.