Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, South China Agricultural University, Guangzhou, China.
Department of Entomology, University of Kentucky, Lexington, KY, USA.
Pest Manag Sci. 2020 Nov;76(11):3606-3614. doi: 10.1002/ps.5894. Epub 2020 Jun 2.
Most recently, major federal regulatory agencies deregulated an in planta RNA interference (RNAi) trait against a devastating corn pest, the western corn rootworm Diabrotica virgifera virgifera, in the United States and Canada. The impact of double-stranded RNA (dsRNA) plant-incorporated protectants (PIPs) and dietary RNAi to non-target organisms, however, still needs further investigation. In this study, we assessed the potential risks of a Diabrotica virgifera virgifera active dsRNA to a group of predatory biological control agents, including Hippodamia convergens, Harmonia axyridis, Coleomegilla maculata, and Coccinella septempunctata. The overarching hypothesis is that the insecticidal dsRNA targeting Diabrotica virgifera virgifera has no or negligible adverse effect on lady beetles.
A 400-bp fragment with the highest sequence similarity between target and tested species was selected as the template for dsRNA synthesis. For the dietary RNAi toxicity assay, newly hatched first instar larvae were administered with v-ATPase A dsRNAs designed from Diabrotica virgifera virgifera and the four lady beetles, respectively. A dsRNA from β-glucuronidase (GUS), a plant gene, and H O were served as the negative controls. The endpoint included both sub-organismal (gene expression), and organismal (survival rate, development time, pupa and adult weight) measurements. The results from dietary RNAi toxicity assay demonstrate significantly impacts of Diabrotica virgifera virgifera-active dsRNAs on lady beetles under the worst-case scenario at both transcriptional and phenotypic level. Interestingly, substantial differences among the four lady beetle species were observed toward the ingested exogenous dsRNAs.
Such differential response to dietary RNAi may shed light on the mechanisms underlying the mode-of-action of RNAi-based biopesticides. © 2020 Society of Chemical Industry.
最近，美国和加拿大的主要联邦监管机构取消了对一种毁灭性玉米害虫——西部玉米根虫 Diabrotica virgifera virgifera 的植物内 RNA 干扰（RNAi）特性的监管。然而，双链 RNA（dsRNA）植物整合保护剂（PIP）和膳食 RNAi 对非靶标生物的影响仍需要进一步研究。在这项研究中，我们评估了 Diabrotica virgifera virgifera 活性 dsRNA 对一组捕食性生物防治剂的潜在风险，包括 Hippodamia convergens、Harmonia axyridis、Coleomegilla maculata 和 Coccinella septempunctata。总体假设是，针对 Diabrotica virgifera virgifera 的杀虫 dsRNA 对瓢虫没有或几乎没有不良影响。
选择与靶标和测试物种具有最高序列相似性的 400bp 片段作为 dsRNA 合成的模板。对于膳食 RNAi 毒性测定，新孵化的第一龄幼虫分别用 Diabrotica virgifera virgifera 和四种瓢虫的 v-ATPase A dsRNA 处理。β-葡萄糖醛酸酶（GUS）的 dsRNA，一种植物基因，以及 H2O 作为阴性对照。终点包括亚机体（基因表达）和机体（存活率、发育时间、蛹和成虫体重）测量。膳食 RNAi 毒性测定的结果表明，在转录和表型水平上，最不利情况下，Diabrotica virgifera virgifera 活性 dsRNA 对瓢虫有显著影响。有趣的是，四种瓢虫对摄入的外源性 dsRNA 表现出明显的差异。
这种对膳食 RNAi 的差异反应可能揭示了基于 RNAi 的生物农药作用模式的机制。© 2020 化学工业协会。
