Sprayable formulations of dsRNA as a tool for management of Popillia japonica (Coleoptera: Scarabaeidae)

Abstract

RNA interference (RNAi) mediated by environmental dsRNA presents a promising, target-specific approach to providing plant-protection against damage from invasive and outbreak insect pests. However, this approach has not been optimized for most species and multiple limitations still need to be addressed. These limitations include preliminary degradation by abiotic and biotic degradative factors and poor cellular uptake and transport to target cells. The primary objective of this study was to develop a platform for sprayable formulations of dsRNA for the management of Japanese beetle (Popillia japonica) by evaluating target genes and technologies that could aid in overcoming limitations with stability and transport. First, in collaboration with Dr. Avila-Flores lab, I evaluated whether complexing dsRNA with peptide nanoparticles named Branched Amphiphilic Peptide Capsules (BAPCs) would increase the efficacy of gene silencing of a peritrophin gene majorly expressed in midgut tissue in adults. Then, I determined the primary transport mechanism of cellular uptake of BAPC-dsRNA complexes into the larval midgut tissue. Lastly, in collaboration with Dr. Reddy Palli’s lab, I conducted field experiments to determine whether dsRNA targeting an actin gene specific to P. japonica would provide plant protection to roses when applied as a foliar spray. Overall, this study provides insights that may aid in decision making when considering target life stage, gene, and necessary inert ingredients for producing gene silencing and efficient mortality.