拮抗性链霉菌对大丽轮枝菌微菌核形成与萌发的影响

为探索拮抗性链霉菌对棉花黄萎病病原大丽轮枝菌Verticillium dahliae Kleb.的抑菌机制,采用菌丝生长速率法、微菌核萌发法研究了6株拮抗链霉菌无菌发酵滤液对大丽轮枝菌生长、微菌核形成与萌发的影响。链霉菌无菌发酵滤液对大丽轮枝菌菌落生长、菌核形成和微菌核萌发有明显抑制作用。其中菌株B49的抑菌效果最好,5倍稀释发酵液培养14天时对菌落生长的抑菌率达69.7%;菌株B49、D184和Act12的5倍稀释发酵液对微菌核形成的抑制率达100%;将经B49、D184和Act12发酵液处理后丧失形成微菌核能力的大丽轮枝菌菌株转接至不含发酵液的PDA培养基,连续传代至第5代,其仍然不能恢复形成微菌核的能力;微菌核在含有菌株D184 5倍稀释发酵液的培养基上培养168 h时,萌发率仅为38.3%。

Inhibition of antagonistic Streptomyces spp. on microsclerotia formation and germination of Verticillium dahliae

The antifungal mechanism of antagonistic Streptomyces spp. against Verticillium dahliae Kleb. was studied. The inhibitory effect of six Streptomyces strains culture filtrate on mycelium growth, microsclerotia formation and germination of V.dahliae were tested by means of the methods of mycelium growth rate and microsclerotia germination. The results showed that mycelium growth of V.dahlia was inhibited by culture filtrates of Streptomyces. Culture filtrate of Streptomyces B49 strong inhibited mycelium growth of V.dahlia; the inhibition rate of 5-fold-dilution culture filtrate against mycelium growth of V.dahliae was 69.7% at 14 d. Microsclerotia formation of V.dahlia was inhibited by culture filtrate of Streptomyces. 5-fold-dilution culture filtrates of Streptomyces isolates B49, D184 and Act12 displayed completely inhibitory effects on microsclerotia formation of V.dahlia with 100% of inhibitory rate. Mutant strain of V.dahliae which obtained from these three Streptomyces culture filtrate treatments did not produce microsclerotia; they were not reversed to wild type on PDA medium after five times subculture. Microsclerotia germination of V.dahliae was also inhibited by culture filtrate of Streptomyces, the germination rate of isolate D184 5-fold-dilution culture filtrate was 38.3% at 168 h.