Abstract: Insecticidal Cry toxins produced by Bacillus thuringiensis are used worldwide in transgenic crops for efficient pest control. Among the family of Cry toxins, the three dimensional structure domain of Cry family leading to the natural evolution, and producing a large number of Cry proteins with similar structure and mode of action but different insect specificity. Also, this group is the basis of the molecular study on insect specificity. This article briefly described the Bt and its development. Furthermore, the paper expounded the natural evolution on the insect specificity and its action mechanism of Cry toxins. Finally, we proposed a general strategy for in vitro evolution of Cry toxins insecticidal activity.

Key words: Bacillus thuringiensis, Cry toxin, evolution, action mechanism

摘要： 苏云金芽胞杆菌（简称Bt）产生的杀虫Cry毒素被广泛的运用于转基因作物害虫的有效防治。在Cry毒素家族中，Cry毒素的三维结构域引导它们自然进化,并产生大量结构和行为方式相似但在不同的昆虫中表现出不同特异性的Cry蛋白，同时Cry毒素家族也是对昆虫特异性分子研究的基础。简述了Bt本身及其发展历程，还详细阐述了Cry毒素在自然中完成昆虫特异性的进化及其作用机制。最后，对于Cry毒素杀虫活性的进化提出了一般性的策略。

关键词: 苏云金芽胞杆菌, Cry毒素, 进化, 作用机制