嗜线虫致病杆菌YL001菌株代谢产物的抑菌活性

The antifungal activity of secondary metabolic products from Xenorhabdus nematophilus YL001

从陕西杨凌土样中筛选得到一株昆虫病原线虫,从其体内分离到它的共生菌嗜线虫致病杆菌Xenorhabdusnematophilus,编号为YL001,为明确其代谢产物的抑菌活性,本试验采用抑制菌丝生长速率法、抑制孢子萌发法、组织测定法和盆栽试验法系统测定了其发酵液对植物病原真菌的抑制作用。结果表明,在离体条件下该菌株发酵液对供试的15种植物病原真菌菌丝生长均有一定的抑制作用,对番茄灰霉病菌和辣椒疫霉病菌的抑制作用最强,EC50分别为53.54和90.39mg·L-1;对供试的6种植物病原真菌孢子萌发均有一定的抑制作用,其中对番茄灰霉病菌和烟草赤星病菌孢子萌发有较强的抑制作用,EC50仅分别为16.97和21.87mg·L-1;组织法测定中,发酵液稀释10倍后,对番茄灰霉病的保护效果为74.98%,治疗效果为63.50%;对盆栽番茄灰霉病的保护效果为65.11%,治疗效果为54.64%。显微观察表明,YL001菌株的发酵液可使菌丝生长形态异常、变形萎缩,甚至断裂。

This study investigated the antifungal activity of secondary metabolic products from Xenorhabdus nematophilus YL001 in vitro and in vivo. The results indicated that the supernatant of the bacteria broth inhibited mycelial growth of 15-species plant-pathogenic fungal in vitro. It especially could markedly inhibited the mycelial growth to Botrytis cinema and Phytophthora capsici. Their EC50 value against Bot- rytis cinerea and Phytophthora capsici were 53.54 mg·L^-1 and 90.39 mg·L^-1 , respectively. The spore germination EC50 value against Botrytis cinerea and Alternaria alternata were 16.97 mg·L^-1 and 21.87 mg·L^-1, respectively. In addition, protective effect and therapeutic effect of the fermentation products diluted 10 times against the Botrytis cinema were 74.98% and 63.50% on tomato, respectively. Finally protective effect and therapeutic effect of the fermentation products against the Botrytis cinerea were 65.11% and 54.64% on cucumber in potted, respectively. The decrease of spore germination rate and the abnormal hyphal growth was observed under microscope.