对二点委夜蛾高毒力苏云金芽胞杆菌的筛选及其基因型分析
Selection and genotype analysis of Bt isolates with high virulence against Athetis lepigone (Moschler)
杨云鹤1** 宋 萍1 王振营2 董志平3 王勤英1***
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作者单位：1. 河北农业大学 植物保护学院 保定 071000；2. 中国农业科学院植物保护研究所 北京 100193；3. 河北省农林科学院谷子研究所 石家庄 050035
中文关键词：苏云金芽胞杆菌，二点委夜蛾，基因型鉴定，杀虫活性，Vip3A蛋白，Cry1Ac蛋白
英文关键词：Bacillus thuringiensis, Athetis lepigone, genotype identification, insecticidal activity, Vip3Aprotein, Cry1Acprotein
中文摘要： 【目的】 获得对二点委夜蛾Athetis lepigone（Möschler）高毒力的苏云金芽胞杆菌（Bt）菌株，寻找对该虫具有特异杀虫活性的蛋白毒素，探索Bt菌株或其杀虫基因应用于二点委夜蛾防治的可行性。【方法】 通过生物测定方法比较了36株苏云金芽胞杆菌和一株恶臭假单胞工程菌PHB-cry1Ab对二点委夜蛾幼虫的杀虫活性，同时利用PCR-RFLP方法对这些菌株的基因型进行了分析。【结果】 不同Bt菌株对二点委夜蛾幼虫的杀虫活性差别很大，杀虫活性高的菌株都含有cry1Ac基因。饲毒72 h 后含单基因的Bt HD-73菌株（cry1Ac）对二点委夜蛾2龄幼虫的毒力（LC50值为188.51 μg/g）明显高于含多基因的Bt SC-40菌株（cry1Ac，cry2Ac，cry1I，vip3A）的毒力（LC50值为418.13 μg/g）。含有vip3A基因的Bt SC-40和Bt HD-1营养期上清液对二点委夜蛾2龄幼虫表现出一定的杀虫活性（72 h死亡率分别达到42.5%和57.4%），而无vip3A基因的Bt HD-73营养期上清液未表现出明显的杀虫活性。【结论】 由cry1Ac基因编码的Cry1Ac蛋白对二点委夜蛾幼虫具有特异杀虫活性，Vip3A蛋白对二点委夜蛾幼虫可能也有一定的杀虫活性。
英文摘要： [Objectives] To obtain Bt strains and insecticidal proteins with high insecticidal activity against Athetis lepigone (Möschler). [Methods] The insecticidal activities of 36 Bt strains and an engineered Pseudomonas putida with a cry1Ab gene were evaluated on second instar larvae of A. lepigone by bioassay. PCR-RFLP analysis was performed to verify the genotypes of all Bt isolates. [Results] The bioassay results indicated obvious differences in the insecticidal activities of the different Bt isolates tested. The results also revealed that the Bt strains with high insecticidal activity all contained the cry1Acgene. Furthermore, the results of a comparison of the toxicities of Bt SC-40 (cry1Ac, cry2Ac, cry1I, vip3A) and Bt HD-73 (cry1Ac) showed that the LC50 of BT HD-73 (188.51 μg/g) was lower than that of Bt SC-40 (418.13 μg/g). The supernatants from the vegetative stage of Bt SC-40 and Bt HD-1 with the vip3A gene showed certain insecticidal activities (42.5 % and 57.4 % mortality, respectively) to second instar larvae of A. epigone. However, the supernatants of Bt HD-73 with no vip3A gene did not show obvious insecticidal activity. [Conclusion] These results imply that the Cry1Actoxin encoded by the cry1Ac gene play an important role in the resistance of plants to A. lepigone larvae. Vip3Amay also have some insecticidal properties with regard to this pest.