我国不同森林立地带Bt分离株杀虫晶体蛋白及基因分析

ANALYSIS OF INSECTICIDAL CRYSTAL PROTEIN AND ITS CRY-TYPE GENES OF BACILLUS THURINGIENSIS ISOLATES FROM CHINA

利用苏云金芽孢杆菌cry基因的PCR RFLP鉴定体系和SDS PAGE方法分析了来自我国不同森林立地带土壤中的 72株苏云金芽孢杆菌的cry1、cry2、cry3、cry4、cry5、cry8、cry9、cry10、cry11、cry1I等 10类基因类型和表达蛋白 ,并进行了杀虫活性的生物测定。研究表明 :同时含有cry1,cry2 ,cry1I 3类基因的有 2 1株菌 ,6株菌含有cry1,cry2类基因 ,4株菌含有cry1和cry1I类基因 ,只含有cry1基因的有 1株 ,cry2类基因的 4株 ,36株菌不含所鉴定的 10类cry基因。同时证明 ,绝大多数含有cry1基因的菌株表达了 130kDa蛋白 ,含有cry2基因的菌株表达了 6 0kDa蛋白。生物活性测定表明 ,共同含有cry1Aa、cry1Ac和cry2基因的菌株对棉铃虫幼虫具有较强的杀虫活性 ,只含有单一基因和不含上述基因的菌株杀虫活性较弱。

Based on the method of PCR RFLP and SDS PAGE, cry genes and their expression products of 72 isolates of Bacillus thuringiensis from different forestry site zones in China were analyzed. Result showed that twenty one strains contained three cry type genes: cry1, cry2 and cry 1I, six strains contained both cry 1 and cry 2 genes, four strains contained both cry 1 and cry 1I type genes, one strain contained cry 1 type gene, four strains contained cry 2 type gene. 36 strains did not contain ten cry type genes. Most cry 1 genes encoded 130 kDa protein toxic to Lepidopteran pest, and most cry2 genes encoded 60 kDa protein.The isolates containing cry 1Aa, cry 1Ac and cry 2 type genes were highly toxic to Helicoverpa armigera larvae, isolates containing one or no cry gene had low or no toxicity activity to pests.