Virulence of vegetative insecticidal proteins Vip3Aa60 and Vip3Ad5 of Bacillus thuringiensis against

• 作 者: Zhizhen Pan Huanjuan Gao Yujing Zhu Lian Xu Xiong Guan Qingxi Chen Bo Liu
• 机 构: Agricultural Bio-Resources Institute,Fujian Academy of Agricultural Sciences,Fuzhou,China;Key Labora
• 出 处: 中国生物化学与分子生物学会2016年全国学术会议
• 发表日期: 2016年3期
• 关键词: Vip3Aa60 Vip3Ad5 Insecticidal activity Spodoptera exigua

　　Vegetative insecticidal proteins(Vips)secreted by Bacillus thuringiensis(Bt)strains during the vegetative growth stage,were seemed as the second generation of Bt insecticides.A number of Bt isolates were indicated in screening tests.Two novel vip3A genes with 2370 bp and 2361 bp in length were classified as vip3Aa60(NCBI accession No.: KR340473)and vip3Ad5(NCBI accession No.: KR263164),respectively.There were two mutations in both vip genes which led to two amino acids modification.Homology modeling results indicated that the two amino acids mutations of Vip3Ad5(Met3 and Ala6)were both located in the loop,while the Met3 of Vip3Aa60 was in the loop and the Glu337 of Vip3Aa60 was in the-hαelix.After expression of these vip genes,the proteins were purified and characterized.The toxicity of both toxins was estimated against lepidopteran pests of Spodoptera exigua.The results were interesting that Vip3Aa60 had high toxicity against S.exigua as the LC50 value was 28.9 ng/cm2 but Vip3Ad5 toxin displayed no toxicity to S.exigua yet.The insecticidal mechanism of Vip3Aa60 and Vip3Ad5 was further study from the proteolytic processing,the core peptidase stability and the mode of interaction with their receptors.