广谱高效Bt菌株的筛选及其杀虫蛋白基因的克隆

Screening of Bacillus thuringiensis strain with broadspectrum and high toxicity and cloning of its insecticidal crystal protein gene

摘要: 通过杀虫活性测定，获得1株对菜青虫、小菜蛾、二化螟等多种鳞翅目害虫均有较高杀虫活性的高效苏云金芽孢杆菌Bacillus thuringiensis（Bt）菌株，命名为X-2．同时根据Cryl类蛋白N端部分氨基酸序列设计了1对简并引物，以苏云金芽孢杆菌X-2菌株质粒DNA为模板，应用PCR扩增技术得到一大小为3468bp的DNA片段（Cry1Ab X-2）．该基因编码1155个氨基酸，相对分子质量为130780，等电点pI=5．06．序列比较表明该基因与Cry1Ab类基因高度同源（达95％以上），该基因已在GenBank中登录，登录号为AY847289．

Abstract: After the determination of insecticidal activity,one Bacillus thuringiensis strain,showing high toxic to Pieris rapae,Plutclla xylostella and Chilo suppressalis,was obtained and named Bt X-2.Degenerate primers were designed based on the N-terminal partial sequence of Cry1 to amplify the corresponding DNA sequence by touchdown PCR.The amplified fragment,with the length of 3 468 bp,encoding(1 155) amino acid with M_r=130 780 and pI=5.06.The amino acid sequence of Cry1Ab X-2 gene showed more than 95% identity to other Cry1Ab,and it was registered in GenBank(Accession No.AY847289).