Gene Regulation by RNAi on Apis mellifera ligustica Colonies Based on Engineering Bacteria and Nanomaterials

Honey bees, as indispensable pollinators, can promote agricultural production and maintain ecological balance. Because of honey bees' eusociality, studying honeybee colonies is of great importance. RNA interference (RNAi) has emerged as a powerful tool for honey bee research. However, the application of RNAi in honey bee colonies is frequently impeded by challenges related to the efficient delivery and mass synthesis of dsRNA. In this study, we developed a novel field-based RNAi method for Apis mellifera ligustica Spinola (Hymenoptera: Apidae) colonies by feeding them nanomaterial-encapsulated dsRNA (SPc-loaded dsRNA) synthesized using the pET28-BL21(DE3) RNase III- system. Firstly, we demonstrated that A. mellifera preferred honey solutions containing ultrasonically disrupted E. coli to the original solutions. Secondly, we found that SPc not only effectively protected dsRNA from degradation by honey bee intestinal fluids but also enhanced RNAi efficiency. Finally, we observed a significant reduction in target gene expression levels after implementing RNAi in small hives equipped with automatic feeders, by delivering SPc-loaded dsRNA in a field setting. This is an innovative method to implement RNAi on honey bee colonies based on E. coli and the SPc in the field. The approach provides valuable insights into dsRNA synthesis for honey bees and RNAi implementation in honey bee colonies. This approach holds promise for promoting honey bee research on colony level, ultimately contributing to ecological balance and biodiversity.