小麦纹枯病菌拮抗链霉菌SCY505的筛选与鉴定

从河南省许昌地区的小麦田土样中分离到1株对小麦纹枯病菌有稳定拮抗作用的链霉菌菌株SCY505。在形态特征、生理生化特性和细胞壁化学组分分析的基础上,结合16S rDNA及16S-23S rDNA intergenic spacer region(ISR)序列分析,对菌株SCY505进行了分类鉴定,同时测定了该菌株的拮抗谱。结果表明,SCY505的基内菌丝无横隔,不断裂;气生菌丝多分枝,孢子丝直生或呈螺旋状,孢子椭圆形或圆柱形,表面光滑;细胞壁化学组分Ⅰ型;16S rDNA序列长度1521bp(GU045548),与淡紫灰链霉菌的16S rDNA序列同源性达99.7%,ISR序列长度372bp(GU358067),与淡紫灰链霉菌亚种(U93347)的ISR序列同源性为82.9%,初步认为SCY505是淡紫灰链霉菌的一个亚种,暂命名为淡紫灰链霉菌许昌亚种(Streptomyces lavendulaesub sp.xuchangensis)。该菌株对供试的10种植物病原真菌均有较好的抑制效果。

Screening and Identification of Streptomyces Strain SCY505 against Rhizoctonia cerealis

A Streptomyces strain SCY505,which strong inhibited the growth of Rhizoctonia cerealis,was isolated from the wheat cultural soil samples collected from Xuchang area in Henan province.Identification of the strain SCY505 was conducted by analysis of 16S rDNA and 16S-23S rDNA intergenic spacer region sequences based on determination of morphological,physical and biochemical characteristics.The results were as follows: substrate mycelium of strain SCY505 had no branch,while its aerial hypha was much-branched.Spore chains were straight or spiral and spores were oval or cylindrica1 with smooth surface.The composition of cell wall belonged to typeⅠ.The 1521bp 16S rDNA sequence from strain SCY505(GU045548) showed 99.7% identity to Streptomyces lavendulae(DG645958) and the 372 bp 16S-23S rDNA ISR sequence from strain SCY505(GU358067) showed 82.9% identity to Streptomyces lavendulae subsp(U93347).Therefore,the strain SCY505 was identified as Streptomyces lavendulae subsp.xuchangensis.Antifungal spectrum of strain SCY505 was investigated and found that it had strong antifungal activity against Rhizoctonia cerealis as well as the other nine plant pathogens.