Genotype by Environment Interactions Influencing the Efficacy of Insecticidal RNAi

PROJECT SUMMARY Instructions: The summary is limited to 250 words. The names and affiliated organizations of all Project Directors/Principal Investigators (PD/PI) should be listed in addition to the title of the project. The summary should be a self-contained, specific description of the activity to be undertaken and should focus on: overall project goal(s) and supporting objectives; plans to accomplish project goal(s); and relevance of the project to the goals of the program. The importance of a concise, informative Project Summary cannot be overemphasized. Title: Genotype By Environment Interactions Influencing The Efficacy Of Insecticidal Rnai PD: Teets, Nicholas, M Institution: University of Kentucky CO-PD: Palli, Subba, R Institution: University Of Kentucky CO-PD: PD/PI 3 Name (Last, First, MI) Institution: CO-PD: PD/PI 4 Name (Last, First, MI) Institution: CO-PD: PD/PI 5 Name (Last, First, MI) Institution: CO-PD: PD/PI 6 Name (Last, First, MI) Institution: CO-PD: PD/PI 7 Name (Last, First, MI) Institution: RNA interference (RNAi) is a natural gene silencing mechanism with promising applications for insect pest control. Foliar application or transgenic expression of gene-specific double stranded RNAs (dsRNAs) causes gene silencing and insect death, and this technology affords an attractive alternative to chemical insecticides and can be applied to a variety of pests. However, there are growing concerns over resistance and the long-term prospects of this technology. RNAi susceptibility is likely a function of both genotype and environment, and variability in RNAi across environments could facilitate the evolution of resistance. Also, refractoriness to RNAi in certain environments may necessitate higher doses, which can increase environmental risks. Here, we use Colorado potato beetle (CPB) to investigate genotype-by-environment interactions that shape RNAi susceptibility. Our preliminary data indicate that efficacy decreases at lower temperatures, suggesting that environmental conditions may influence baseline susceptibility and thus the resistance evolution. In Objectives 1 and 2, we will quantify RNAi susceptibility in three beetle populations exposed to distinct temperatures and host plants to test the extent to which dsRNA toxicity varies across genetic backgrounds and environments. In Objective 3, we will test the hypothesis that environmentally mediated variation in RNAi susceptibility is caused by disruption of dsRNA transport and processing, and we will use transcriptomics to identify novel mechanisms associated with variation in RNAi susceptibility. Together, these experiments will provide critical insights into conditions that may compromise RNAi efficacy and contribute to USDA BRAG’s goal of understand the mechanisms by which pests become resistance to engineered control traits. This file MUST be converted to PDF prior to attachment in the electronic application package.