LncRNA6470/ace-miR-750-y axis modulates AcPP2A gene, immune response and survival of eastern honey bee larvae during fungal infection.

内容摘要

Chalkbrood, a destructive larval disease caused by the fungal pathogen Ascosphaera apis, causes substantial losses in apiculture. Although host-pathogen interactions in Apis mellifera larvae infected with A. apis have been investigated, immune defense mechanisms in the Asian honey bee Apis cerana remain unclear. This study examined whether the lncRNA6470/ace-miR-750-y axis modulates the response of A. cerana larvae to A. apis infection. Stem-loop RT-PCR, Sanger sequencing, dual-luciferase reporter assays, RNA interference, and RT-qPCR were used to characterize ace-miR-750-y, lncRNA6470, AcPP2A, host immune genes, and selected A. apis genes associated with signal transduction, transcriptional regulation, and RNA metabolism. Larval survival and chalkbrood incidence were also evaluated after ncRNA perturbation. ace-miR-750-y was expressed in larval guts and showed infection-associated expression changes. Computational prediction identified 214 candidate mRNA targets and 143 candidate lncRNA interactors of ace-miR-750-y, from which the lncRNA6470/ace-miR-750-y/AcPP2A axis was selected for experimental validation. Modulation of ace-miR-750-y significantly affected AcPP2A expression. ace-miR-750-y overexpression increased host immune genes associated with antimicrobial peptide production and peroxidase activity, whereas its inhibition reduced their expression. Modulation of ace-miR-750-y was also associated with altered expression of selected A. apis genes and changes in larval survival and chalkbrood incidence. These findings suggest that ace-miR-750-y may play an important regulatory role in the immune response of A. cerana worker larvae to A. apis infection, and that its interaction with lncRNA6470 may contribute to ceRNA-like regulation during fungal challenge.