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

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(B t)菌株,命名为X-2.同时根据Cry1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3 468 bp的DNA片段(Cry1Ab X-2).该基因编码1 155个氨基酸,相对分子质量为130 780,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.

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 Cryl 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 Mr = 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）.