苏云金芽孢杆菌新分离株S_(18-4) δ-内毒素基因在Btk·BE_(20)中的克隆和表达

Cloning and expression of δ endotoxin gene of a new Bacillus thuringiensis isolate S 18 4 in the acrystalliferous strain Btk·BE 20

选用土壤新分离株Ｓ１８－４为供体菌，以ＰＨＴ３１０１穿梭质粒为载体，载体和供体ＤＮＡ用Ｐｓｔｌ酶切后进行连接，用电激法将重组质粒转入苏云金芽孢杆菌无晶体突变株Ｂｔｋ·ＢＥ２０中。经ＳＤＳ－ＰＡＧＥ蛋白电泳及扫描电镜观察，证明δ－内毒素基因得到了表达，并具有很高的表达量。生物测定结果显示，重组株对夜蛾科幼虫具有比野生株Ｓ１８－４更强的杀虫毒性。

A new Bacillus thuringiensis isolate(S 18 4 ) from soil was used as the donor of δ endotoxin gene.A shuttle vector(PHT3101) was used as an expression vector in the acrystalliferous strain Btk·BE 20 .The purified plasmid DNA are completely digested with Pstl restriction enzyme and ligated with T 4 ligase. The recombinant plasmid was transfered into Btk·BE 20 by electroporation.SDS PAGE and scanning electron microscopy showed that the δ endotoxin gene were expressed in high level in Btk·BE 20 . The recombinant strain showed higher toxicity than the donor strain S 18 4 to Prodenia litura larvae.