Yuan Xiangdong, Zhao Man, Wei Jizhen, Zhang Wanna, Wang Bingjie, Myint Khaing Myint, Liang Gemei
State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
J Insect Physiol. 2017 Apr;98:101-107. doi: 10.1016/j.jinsphys.2016.12.004. Epub 2016 Dec 27.
Cry1A and Cry2A toxins, which are widely used in Bt transgenic crops, can specifically bind to insect midguts and exert their insecticidal effects. There are interactions between insect midgut-binding proteins and Cry1A toxins; however, little is known about the insect protein that specifically binds to Cry2A. Midgut membrane-bound alkaline phosphatases (ALPs), which are important for the binding of proteins to Cry1A, play dominant roles in Cry1A-mediated toxicity in some lepidopteran larvae. In this study, we cloned and expressed one partial ALP2 peptide from susceptible Spodoptera exigua larvae and studied the binding characteristics of SeALP2 with Cry2Aa. The ALPs proteins was expressed at all larval stages and highly expressed in the first and second instar larvae. The heterologously expressed SeALP2 peptide bound specifically to Cry2Aa with a high affinity. Knocking down ALP2 in vivo revealed that it plays an important role in the susceptibility of S. exigua to Cry2Aa. Based on these findings, we propose that ALP2 in S. exigua serves as a functional receptor for Cry2Aa.
广泛应用于Bt转基因作物中的Cry1A和Cry2A毒素，能够特异性地结合昆虫中肠并发挥其杀虫作用。昆虫中肠结合蛋白与Cry1A毒素之间存在相互作用；然而，对于特异性结合Cry2A的昆虫蛋白却知之甚少。中肠膜结合碱性磷酸酶（ALPs）对蛋白质与Cry1A的结合至关重要，在某些鳞翅目幼虫中，其在Cry1A介导的毒性中起主要作用。在本研究中，我们从敏感的甜菜夜蛾幼虫中克隆并表达了一条部分ALP2肽段，并研究了SeALP2与Cry2Aa的结合特性。ALPs蛋白在所有幼虫阶段均有表达，在一龄和二龄幼虫中高表达。异源表达的SeALP2肽段以高亲和力特异性结合Cry2Aa。体内敲低ALP2表明其在甜菜夜蛾对Cry2Aa的敏感性中起重要作用。基于这些发现，我们提出甜菜夜蛾中的ALP2作为Cry2Aa的功能性受体。
