一株对蚊子幼虫高效的Bt新菌株的特性研究

摘要

苏云金芽胞杆菌WFS-97菌株是从土壤中筛选出的对蚊子幼虫具有特异杀虫活性的新菌株,本研究通过对该菌株的形态特征、培养特性及杀虫基因型的研究,了解其作为杀蚊制剂的开发应用潜力.在光学显微镜下,观察该菌株产生球形伴胞晶体,SDS-PAGE检测显示主要表达27 kDa主要蛋白条带,此外,还有131、79、43和31 kDa等多个较浅的蛋白条带.PCR-RFLP分析结果表明,该菌株含有cry30与cyt2基因.生物活性测定表明该菌株对鳞翅目幼虫小菜蛾、棉铃虫及亚洲玉米螟均无明显的杀虫活性,但对淡色库蚊和白纹伊蚊2龄幼虫的杀虫活性高于标准菌株苏云金芽胞杆菌以色列亚种.%A sporulating culture of Bacillus thuringiensis isolate WFS-97 from soil in Hebei province is toxic to larvae of mosquito. In order to determine the potential value as mosquitocide,Bt WFS-97 was further characterized by SDS-PAGE, light microscopy, PCR. Bt WFS-97 formed the spherical crystal observed by optical microscope. SDS-PAGE analysis revealed five protein bands with molecular masses of 131, 79, 43, 31 and 27 kDa,but only 27 kDa protein band was prominent. Two novel crystal protein genes, cry30 and cyt2, were identified by using the PCR-RFLP method in this isolate. The bioas-say results indicated that Bt WFS-97 toxin protein had higher insecticidal activity against second instar larvae of Culex pipiens and Aedes albopictus than B. Thuringiensis subsp. Israelensis. The isolate showed no any insecticidal activities against second instar larvae of Helicoverpa armigera, Plutella xylostella and Ostrinia furnacalis.