对美国白蛾高毒Bt的筛选和杀虫蛋白基因鉴定

Identification of insecticidal crystal protein gene and isolation of Bacillus thuringiensis strains toxic to Hyphantria cunea

通过生物测定,从山东省不同地区分离和本实验室保存的122株苏云金芽孢杆菌Bacillus thuringiensis(简称Bt)中筛选到16株对美国白蛾Hyphantria cunea具有高毒力的菌株,用SDS-PAGE和PCR-RFLP方法对16株Bt的杀虫蛋白和杀虫基因类型进行鉴定。结果表明,有11株Bt菌株中同时含有130kDa和60或70kDa的蛋白,1株同时含有130和140kDa的蛋白,3株只含有130kDa的蛋白,1株含有30kDa的蛋白;有14株Bt同时含有cry1和cry2类杀虫蛋白基因,其中4株还包括cry9类基因,2株Bt中没有鉴定到已知基因类型,可能含有新的杀虫基因。16株Bt菌株均不含cry3、cry4、cry8和cry10类基因。

Based on bioassay, 16 strains of Bacillus thuringiensis（Bt） showed highly toxic to Hyphantria cunea larvae were screened from 122 strains isolated from soil in Shandong Province of China and preserved in our lab. The expression of insecticidal crystal proteins and the types of cry gene of the 16 strains were identified with the SDS-PAGE and PCR-RFLP methods. Results showed that 11 strains expressed both 130 and 60 or 70 kDa proteins, 1 strain expressed both 130 and 140 kDa proteins,3 strains expressed 130 kDa protein only, 1 strain expressed 30 kDa protein. 14 strains contained both cryl and cry2 genes,4 strains contained cry9-type gene, all of 16 strains did not contain cry3, cry4, cry8, and cryl0 genes. Two strains did not give any PCR products of identified cry genes, which indicated they may contain a novel cry-type gene.