Evaluation of dsRNAs targeting different genes in control of Colorado potato beetle (Leptinotarsa decemlineata)

RNA interference (RNAi) serves as a versatile genetic tool capable of selectively inhibiting the expression of specific genes, providing a promising avenue for preventing crops from being infested by insect pests and diseases. In this study, RNAi was employed to investigate its effects on the Colorado Potato Beetle (Leptinotarsa decemlineata Say). The double-stranded RNAs (dsRNAs) were synthesized using L4440 vector in Escherichia coli HT115 strain to silence the L. decemlineata Vacuolar ATPase (V-ATPase), Ultraspiracle protein (USP), and Ecdysone receptor (EcR) mRNAs which are essential for a range of physiological and developmental processes. The results revealed that RNAi increased mortality rates, significant effects on larval weight gain, reduced foliage consumption, and suppression of egg-laying behavior in L. decemlineata. The targeted downregulation of gene expression, as evidenced by reduced mRNA levels, confirmed the efficacy of RNAi. Additionally, combining dsUSP and dsEcR showed a synergistic effect, demonstrating the greatest mortality rate recorded at 90% in larvae, with 88% reduction in the number of laid eggs compared to their individual applications in feeding bioassays. This study shows that employing RNAi technology has the potential to effectively control this devastating potato pest by providing a targeted approach to suppress its population. Keywords: RNA interference, feeding bioassay, mortality, mRNA level, synergism