西瓜枯萎病生防菌枯草芽孢杆菌B11菌株高产拮抗物质的诱变选育

Mutation screening of high antagonistic substance-producing activity strain in Bacillus subtilis strain B11 for watermelon wilt

从西瓜根围分离得到的一株有效抑制西瓜枯萎病菌的枯草芽孢杆菌B 11菌株(B acillus subtilisstra in B 11)。为获得高产拮抗物质的诱变菌株,采用紫外线诱变方法对B 11菌株进行诱变,结果获得抑菌活性比野生菌B 11菌株强的6株诱变菌株,其中G 17菌株的抑菌活性及粗拮抗物质含量均高于B 11菌株,且遗传性较稳定;再以G 17菌株为供试菌株,用亚硝基胍(NTG)对其进行化学诱变,结果获得抑菌活性较强的4株诱变菌株,其中BV 22菌株对西瓜枯萎病菌的抑菌活性最高,其抑菌活性比G 17和B 11菌株分别提高了36.88%和80.00%;其粗拮抗物质的含量分别提高了30.15%和62.53%。研究结果说明,用物理诱变B 11菌株后获得的诱变菌株再用化学方法进行诱变,可选育出高产拮抗物质的诱变菌株。

Bacillus subtilis strain Bll isolated from rhizosphere of watermelon was strongly inhibition to the growth of the pathogen of watermelon wilt. To obtain high antagonistic substance producing activity strain, Bacillus subtilis strain Bll was treated with ultraviolet radiation. Six mutation strains, which had higher antagonistic activity against the pathogen of watermelon wilt than wild strain B11, were obtained. Strain G17 produced the highest quantity of antagonistic substance in six strains. Strain G17 was then treated with nitrosoguanidine （NTG）. Four strains, which had higher antagonistic activity than strain G17,were obtained. The antagonistic activity of strain BV22 increased 36.88% and 80.00% than that of strain G17 and Bll respectively. The resuh showed that high antagonistic substance-producing activity strain could be obtained from NTG treatment of the mutants of strain Bll treating with ultraviolet radiation.