Resistance to Bacillus thuringiensis linked with a cadherin transmembrane mutation affecting cellular trafficking in pink bollworm from China
Resistance to Bacillus thuringiensis linked with a cadherin transmembrane mutation affecting cellular trafficking in pink bollworm from China
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DOI：
10.1016/j.ibmb.2018.01.004
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发表时间：
2018-03-01
影响因子：
3.8
通讯作者：
Tabashnik, Bruce E.
中科院分区：
文献类型：
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作者：
Wang, Ling;Ma, Yuemin;Tabashnik, Bruce E.
害虫抗性的进化降低了广泛用于喷雾剂和转基因作物的革兰氏阳性细菌苏云金芽孢杆菌（Bt）的杀虫蛋白的功效。在一些先前研究的三种主要鳞翅目害虫菌株中，对 Bt 毒素 Cry1Ac 的抗性与破坏易感幼虫中肠中与 Cry1Ac 结合的钙粘蛋白的细胞外或细胞质结构域的突变有关。在这里，我们报告了第一例与昆虫对 Bt 的抗性相关的钙粘蛋白跨膜突变。我们在全球毁灭性棉花害虫粉红铃虫（Pectinophora gossypiella）的菌株中发现了这种突变，该菌株源自中国长江流域的田间种群。这里分析的突变等位基因有 207 个碱基对缺失，编码缺乏跨膜结构域的钙粘蛋白。相对于易感菌株，该等位基因纯合的菌株对 Cry1Ac 的抗性是 220 倍，对 Cry2Ab 的交叉抗性是 2.1 倍。在产生 Cry1Ac 的转基因棉花植株上，没有易感幼虫存活，但抗性菌株完成了其生命周期。 Cry1Ac 抗性是常染色体隐性遗传，与钙粘蛋白基因紧密相关。钙粘蛋白向细胞膜的转运以及对 Cry1Ac 的敏感性发生在表达野生型钙粘蛋白等位基因的转染昆虫细胞中，但在表达突变型钙粘蛋白等位基因的转染昆虫细胞中则不然。结果表明，此处分析的突变等位基因通过破坏钙粘蛋白的细胞运输而赋予对 Cry1Ac 的抗性。 (C) 2018 Elsevier Ltd. 保留所有权利。
Evolution of pest resistance reduces the efficacy of insecticidal proteins from the gram-positive bacterium Bacillus thuringiensis (Bt) used widely in sprays and transgenic crops. In some previously studied strains of three major lepidopteran pests, resistance to Bt toxin Cry1Ac is associated with mutations disrupting the extracellular or cytoplasmic domains of cadherin proteins that bind Cry1Ac in the midgut of susceptible larvae. Here we report the first case of a cadherin transmembrane mutation associated with insect resistance to Bt. We discovered this mutation in a strain of the devastating global cotton pest, the pink bollworm (Pectinophora gossypiella), derived from a field population in the Yangtze River Valley of China. The mutant allele analyzed here has a 207 base pair deletion and encodes a cadherin protein lacking its transmembrane domain. Relative to a susceptible strain, a strain homozygous for this allele had 220-fold resistance to Cry1Ac and 2.1-fold cross-resistance to Cry2Ab. On transgenic cotton plants producing Cry1Ac, no susceptible larvae survived, but the resistant strain completed its life cycle. Inheritance of resistance to Cry1Ac was autosomal, recessive and tightly linked with the cadherin gene. Transportation of cadherin protein to the cell membrane and susceptibility to Cry1Ac occurred in transfected insect cells expressing the wild type cadherin allele, but not in transfected insect cells expressing the mutant cadherin allele. The results imply that the mutant allele analyzed here confers resistance to Cry1Ac by disrupting cellular trafficking of cadherin. (C) 2018 Elsevier Ltd. All rights reserved.