Spray-induced and nanocarrier-delivered gene silencing system targeting juvenile hormone receptor components: potential application as fertility inhibitors for Adelphocoris suturalis management.

Abstract

Adelphocoris suturalis is a destructive pest that attacks > 270 plants, including cotton, maize, soybean, and fruit trees. Adelphocoris suturalis can cause tremendous crop losses when the density exceeds economic thresholds, but because it can be both phytophagous and zoophytophagous it can serve as a natural enemy of other pests when the density is below the economic threshold. Effective control of its population is beneficial for maximizing yield and profits. RNA interference (RNAi) has potential to be a viable alternative to conventional pesticide-based pest management, but the lack of efficient double-stranded RNA (dsRNA) delivery systems and candidate genes are currently limiting factors for field applications. In this study, RNAi of juvenile hormone (JH) receptor components methoprene-tolerant (Met)/Taiman (Tai) in Adelphocoris suturalis reduced fertility. Based on this reproductive role, we targeted Adelphocoris suturalis Met and Tai for knockdown by coupling nanomaterial-dsRNA complexes with a transdermal spray delivery system. Within 12 h of adult emergence, females were sprayed with star polycation (SPc)-dsRNA formulations and the RNAi effects were assessed over time. RNAi knockdown efficiencies of 39-58% were observed at 5 days post-treatment and abnormal ovarian development was apparent by 10 days post-treatment. Our results show that spray-induced and nanocarrier-delivered gene silencing (SI-NDGS) system targeting JH signal genes effectively impaired oviposition, thus developing a novel RNA fertility inhibitor to control Adelphocoris suturalis populations. These results give new perspective on pest management and suggest broad prospects for field applications. © 2024 Society of Chemical Industry.