College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China.
Department of Entomology, University of Arizona, Tucson, AZ, 85721, USA.
Insect Biochem Mol Biol. 2020 Jun;121:103361. doi: 10.1016/j.ibmb.2020.103361. Epub 2020 Mar 19.
Insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) can provide safe and effective control of some major pests, but evolution of resistance by pests diminishes these benefits. Better understanding of the genetics and mechanisms of resistance is urgently needed to improve methods for monitoring, managing, and countering pest resistance to Bt toxins. Here we used CRISPR-mediated knockouts to evaluate the role of five genes encoding candidate Bt toxin receptors in Spodoptera exigua (beet armyworm), a devastating pest of vegetable, field and flower crops. We compared susceptibility to Bt toxins Cry1Ac, Cry1Fa, and Cry1Ca between the parent susceptible strain and each of five strains homozygous for the knockout of one of the candidate genes (SeAPN1, SeCad1, SeABCC1, SeABCC2 or SeABCC3). The results from the 15 pairwise comparisons reveal that SeABCC2 has a major role and SeCad1 a minor role in mediating toxicity of Cry1Ac and Cry1Fa. SeABCC2 also has a minor role in toxicity of Cry1Ca. In addition, the results imply little or no role for the other three candidate receptors in toxicity of Cry1Ac or Cry1Fa; or for the four candidate receptors other than SeABCC2 in toxicity of Cry1Ca.
苏云金芽孢杆菌（Bt）的杀虫蛋白可以为一些主要害虫提供安全有效的防治，但害虫对这些蛋白产生抗药性会降低这些益处。为了提高监测、管理和应对害虫对 Bt 毒素的抗性的方法，迫切需要更好地了解抗性的遗传学和机制。在这里，我们使用 CRISPR 介导的基因敲除来评估编码候选 Bt 毒素受体的五个基因在甜菜夜蛾（小菜蛾）中的作用，小菜蛾是蔬菜、大田和花卉作物的毁灭性害虫。我们比较了对 Bt 毒素 Cry1Ac、Cry1Fa 和 Cry1Ca 的敏感性，比较了对候选基因之一（SeAPN1、SeCad1、SeABCC1、SeABCC2 或 SeABCC3）纯合敲除的五个近交系与亲代敏感系之间的敏感性。这 15 对比较的结果表明，SeABCC2 在介导 Cry1Ac 和 Cry1Fa 的毒性方面起着主要作用，而 SeCad1 则起着次要作用。此外，结果表明，其他三个候选受体在 Cry1Ac 或 Cry1Fa 的毒性中作用很小或没有作用；或在除 SeABCC2 之外的四个候选受体在 Cry1Ca 的毒性中作用很小或没有作用。
