球孢白僵菌耐吡虫啉突变株的紫外线诱变选育

Breeding of Imidacloprid-tolerant Mutant Strains of Beauveria bassiana Through Ultraviolet Mutagenesis

球孢白僵菌是桑天牛的生物防治菌种，选育对杀虫剂吡虫啉耐受性较强的球孢白僵菌突变株，有益于利用生物防治与化学防治的协同效应防治桑天牛。在含吡虫啉的平板培养基上，利用紫外线对前期筛选出的球孢白僵菌菌株Bb00进行诱变处理，分离筛选到对吡虫啉敏感性明显降低的突变菌株Bb00-UVY1、Bb00-UVY4和Bb00-UVY7，吡虫啉对3个突变菌株的半数最大效应浓度（EC50）分别为原始菌株的13．35、8．84和12．40倍。对其它杀虫剂的交互耐受性试验表明，突变株Bb00-UVYl与Bb00-UVY7对常用杀虫剂阿维菌素、毒死蜱、灭幼脲和氯氰菊酯的交互耐受性更好，这4种杀虫剂对2个菌株的生长抑制率分别在3．08％-12．10％和3．24％～10．21％之间。耐药稳定性试验表明，突变菌株Bb00-UVY1和Bb00-UVY7经连续6次转接后，对吡虫啉的耐受性变化不大，表明突变菌株经传代培养其耐药性能够稳定遗传。

Beauveria bassiana is a biological control strain against Apriona germari. Breeding of imidacloprid-tolerant strains of B. bassiana is beneficial to synergistic control of A. germari using biological and chemical methods. B. bassiana Bb00 strain, which had been obtained from our previous screening work, was irradiated by ultraviolet on PDA medium plate supplemented with imidaclopdri. Three mutant strains Bb00-UVY1, Bb00-UVY4 and Bb00-UVY7 with lower sensitivity to imidacloprid than the original strain was obtained. The concentration for 50% of maximal effect （ECso） of imidacloprid to the above 3 mutant strains was 13.35, 8.84 and 12.40 times to that of the original strain respectively. Bb00- UVY1 and Bb00-UVY7 had better cross tolerance to 4 common pesticides, namely abamectin, chlorpyrifos, chlorbenzuron and cypermethrin. The inhibition rate of these 4 pesticides to Bb00-UVY1 and Bb00-UVY7 ranged from 3.08% to 12.10% and 3.24% to 10.21% respectively. The sensitivity of mutant strains Bb00-UVY1 and Bb00- UVY7 had little change during consecutive sub-culture of 6 generations, indicating that drug resistance of Bb00- UVY1 and Bb00-UVY7 had been stably inherited.