Modulatory Mechanism of the piR-Ame-1128833/ <i>Amlachesin</i> Axis in the Immune Defense of Honey Bee Larvae against Fungal Invasion

The western honey bee is a typical social insect and a vital pollinator for numerous wild plants and crops. Chalkbrood is a fungal disease in honey bees caused by Ascosphaera apis. We recently investigated the role of piR-ame-1128833 in regulating the response of A. mellifera worker larvae to A. apis infection. Herein, we assessed the interaction between piR-ame-1128833 and its potential target gene Apis mellifera lachesin (Amlachesin) and investigated their regulatory relationship by inducing overexpression and knockdown of piR-ame-1128833. Furthermore, RNA interference was used to analyze the regulatory function of Amlachesin in the gut tissue of larvae infected with A. apis. Results revealed that the piR-ame-1128833/Amlachesin axis served as a core regulatory pathway in the immune defense of A. mellifera worker larval guts against A. apis infection. These findings not only provide novel insights into piRNA-mediated epigenetic regulation in honey bees but also improve the understanding of bee–pathogen interactions.