NTG诱变选育抗逆性蜡蚧轮枝菌及其生物学特性测定

Screening of Resistant Mutants by NTG Mutation and Study on Biological Characteristics of Verticillium lecanii

采用NTG对杀虫真菌蜡蚧轮枝菌进行诱变选育,期望获得抗逆性显著增强的菌株,以提高其在田间应用的适应性。以VL-18为出发菌株,用4mg/mL的NTG诱变处理120min,得到耐热性明显提高的诱变菌株NTG-2。抗逆性研究结果表明,NTG-2菌株经40℃水浴处理20min,孢子萌发率比原始菌株提高了251.4%,0.5min内的紫外耐受力提高了145.7%,酸碱耐受力无显著变化。毒力测定结果显示,第5天突变菌株NTG-2对蚜虫的致死中浓度(LC50)比原始菌株降低了98.4%,表明突变菌株的杀虫毒力增强。经多代培养检测,突变菌株的抗逆遗传性能相对稳定。研究表明,通过NTG诱变获得的NTG-2菌株在抗逆方面较原始菌株有所提高。

An insecticidal fungus Verticillium lecanii was mutagenized to screen better field-application ones by NTG mutation methods,which were expected to have great stress tolerance in the field environment.The original strain VL-18 was treated by 4 mg/mL of NTG for 120 min,and then a mutant NTG-2 with higher thermostability was obtained.The stress tolerance of NTG-2 was studied and the results showed that when exposed at 40 ℃ for 20 min,the conidiospore germination rate of NTG-2 was improved by 251.4%,and the UV tolerability was improved by 145.7% within 0.5 min,compared with the original strain.There was no significant change in the anti-acid and anti-base ability.The mutant NTG-2 had a lower LC50 on the fifth day of toxicity test,which was 98.4% lower than the contrast,showing an increase of insecticidal activity.In addition,the resilience genetic performance of NTG-2 was stable after several generations.The results above indicated that the resistance ability of the mutated strain NTG-2 increased.