U.S. Department of Agriculture (USDA), Agricultural Research Service (ARS), U.S. Arid Land Agricultural Research Center, Maricopa, AZ, 85138, USA.
Indian Council of Agricultural Research (ICAR), Indian Institute of Rice Research (IIRR), Rajendra Nagar, Hyderabad, 500 030, India.
Sci Rep. 2018 Sep 10;8(1):13531. doi: 10.1038/s41598-018-31840-5.
Evolution of pest resistance threatens the benefits of genetically engineered crops that produce Bacillus thuringiensis (Bt) insecticidal proteins. Strategies intended to delay pest resistance are most effective when implemented proactively. Accordingly, researchers have selected for and analyzed resistance to Bt toxins in many laboratory strains of pests before resistance evolves in the field, but the utility of this approach depends on the largely untested assumption that laboratory- and field-selected resistance to Bt toxins are similar. Here we compared the genetic basis of resistance to Bt toxin Cry2Ab, which is widely deployed in transgenic crops, between laboratory- and field-selected populations of the pink bollworm (Pectinophora gossypiella), a global pest of cotton. We discovered that resistance to Cry2Ab is associated with mutations disrupting the same ATP-binding cassette transporter gene (PgABCA2) in a laboratory-selected strain from Arizona, USA, and in field-selected populations from India. The most common mutation, loss of exon 6 caused by alternative splicing, occurred in resistant larvae from both locations. Together with previous data, the results imply that mutations in the same gene confer Bt resistance in laboratory- and field-selected strains and suggest that focusing on ABCA2 genes may help to accelerate progress in monitoring and managing resistance to Cry2Ab.
抗虫性的进化威胁到了生产苏云金芽孢杆菌（Bt）杀虫蛋白的基因工程作物的效益。旨在延迟抗药性产生的策略在积极实施时最为有效。因此，研究人员在田间出现抗药性之前，已经针对许多实验室害虫品系选择和分析了对 Bt 毒素的抗性，但这种方法的实用性取决于一个基本未经测试的假设，即实验室和田间选择的对 Bt 毒素的抗性是相似的。在这里，我们比较了对 Bt 毒素 Cry2Ab 的抗性的遗传基础，Cry2Ab 是广泛应用于转基因作物中的毒素，这种抗性存在于来自美国亚利桑那州的实验室选择的种群和来自印度的田间选择的种群之间。我们发现，Cry2Ab 的抗性与破坏同一个 ATP 结合盒转运蛋白基因（PgABCA2）的突变有关，该基因在美国亚利桑那州的实验室选择的品系和印度的田间选择的种群中都存在。最常见的突变是通过选择性剪接导致外显子 6 的缺失，这种突变发生在来自两个地方的抗性幼虫中。结合以前的数据，结果表明，相同基因中的突变赋予了实验室和田间选择的品系对 Bt 的抗性，并表明专注于 ABCA2 基因可能有助于加速对 Cry2Ab 的抗性监测和管理的进展。
