摘要
The relatively low susceptibility ofHelicoverpa armigera to CrylAc, its history of resistance to chemical insecticides and the seasonal decline in expression of CrylAc in transgenic cotton necessitated the development of cotton expressing two insecticidal proteins to provide sustainable control of this multinational pest. To manage the resistance issue, it was essential that the second insecticidal protein have a significantly different mode of action to CrylAc. A common feature of resistance to CrylA proteins in several species as well as H. armigera has been a change in the binding site. A study of binding sites for some Cry proteins in the brush border membrane vesicles （BBMV） ofH. armigera and Helicoverpa punctigera was undertaken. The binding affinity for CrylAc was higher than for CrylAb, matching their relative toxicities, and CrylAc and CrylAb were found to share at least one binding site in both I-1. armigera and I-1. punctigera. However Cry2Aa did not compete with CrylAc for binding and so could be used in transgenic cotton in combination with CrylAc to control H. armigera and manage resistance. Variation in the susceptibilities of three different H. armigera strains to CrylAc correlated with the parameter Bmax/Kcom.
到 Cry1Ac 的 Helicoverpa 有佩带徽章权利的人 a 的相对低的危险性，它到在在转基因的棉花的 Cry1Ac 的表示的化学杀虫药剂和季节的衰落的抵抗的历史要求了表示二杀虫的蛋白质提供这个多民族的害虫的持续控制的棉花的开发。管理抵抗问题，第二杀虫的蛋白质有行动 toCry1Ac 的一个显著地不同的模式，是必要的。到在象 H 一样的几种的 Cry1A 蛋白质的抵抗的一个普通特征。有佩带徽章权利的人啊哈是在有约束力的地点的一个变化。为在刷子的一些叫喊蛋白质的有约束力的地点的研究毗邻 H 的膜泡(BBMV ) 。有佩带徽章权利的人 and Helicoverpa punctigera 被承担。为 Cry1Ac 的 Thebinding 亲密关系比为 Cry1Ab 高，匹配他们毒性， andCry1Ac 和 Cry1Ab 被发现分享在两 H 的至少一个有约束力的地点的亲戚。有佩带徽章权利的人 and H.punctigera。然而， Cry2Aa 没为绑定与 Cry1Ac 竞争能那么与 Cry1Ac 在联合在转基因的棉花被使用控制 H。有佩带徽章权利的人一 and 管理抵抗。Variationin 三不同 H 的危险性。有佩带徽章权利的人一到 Cry1Ac 的紧张与参数 B_( 最大)/K_(com ) 相关。
