Department of Entomology and Nematology, University of Florida, 1881 Natural Area Drive, Steinmetz Hall, Gainesville, FL 32611, United States.
Dow AgroSciences, 9330 Zionsville Road, Indianapolis, IN 46268, United States.
Pestic Biochem Physiol. 2018 Jun;148:103-110. doi: 10.1016/j.pestbp.2018.04.004. Epub 2018 Apr 9.
The use of transgenic crops that induce silencing of essential genes using double-stranded RNA (dsRNA) through RNA interference (RNAi) in western corn rootworm, Diabrotica virgifera virgifera, is likely to be an important component of new technologies for the control of this important corn pest. Previous studies have demonstrated that the dsRNA response in D. v. virgifera depends on the presence of RNAi pathway genes including Dicer-2 and Argonaute 2, and that downregulation of these genes limits the lethality of environmental dsRNA. A potential resistance mechanism to lethal dsRNA may involve loss of function of RNAi pathway genes. Howver, the potential for resistance to evolve may depend on whether these pathway genes have essential functions such that the loss of function of core proteins in the RNAi pathway will have fitness costs in D. v. virgifera. Fitness costs associated with potential resistance mechanisms have a central role in determining how resistance can evolve to RNAi technologies in western corn rootworm. We evaluated the effect of dsRNA and microRNA pathway gene knockdown on the development of D. v. virgifera larvae through short-term and long-term exposures to dsRNA for Dicer and Argonaute genes. Downregulation of Argonaute 2, Dicer-2, Dicer-1 did not significantly affect larval survivorship or development through short and long-term exposure to dsRNA. However, downregulation of Argonaute 1 reduced larval survivorship and delayed development. The implications of these results as they relate to D. v. virgifera resistance to lethal dsRNA are discussed.
利用双链 RNA（dsRNA）通过 RNA 干扰（RNAi）诱导重要基因沉默的转基因作物，可能成为防治这种重要玉米害虫的新技术的重要组成部分。先前的研究表明，dsRNA 在 Diabrotica virgifera virgifera 中的反应取决于 RNAi 途径基因的存在，包括 Dicer-2 和 Argonaute 2，这些基因的下调限制了环境 dsRNA 的致死性。对致死性 dsRNA 产生抗性的一种潜在机制可能涉及 RNAi 途径基因的功能丧失。然而，对 RNAi 技术产生抗性的可能性可能取决于这些途径基因是否具有必需的功能，即 RNAi 途径中的核心蛋白的功能丧失是否会对 D. v. virgifera 的适应性造成代价。与潜在抗性机制相关的适应性代价在决定 RNAi 技术在西方玉米根虫中如何进化抗性方面起着核心作用。我们通过短期和长期暴露于 Dicer 和 Argonaute 基因的 dsRNA，评估了 dsRNA 和 microRNA 途径基因敲低对 D. v. virgifera 幼虫发育的影响。Argonaute 2、Dicer-2 和 Dicer-1 的下调在短期和长期暴露于 dsRNA 时均未显著影响幼虫的存活率或发育。然而，Argonaute 1 的下调降低了幼虫的存活率并延迟了发育。讨论了这些结果与 D. v. virgifera 对致死性 dsRNA 产生抗性的关系。
