Chalkbrood disease, caused by Ascosphaera apis, threatens Apis cerana larvae. However, miRNA-mediated antifungal regulation remains poorly defined. Here, we characterized ace-miR-3759-y in A. apis-challenged A. cerana larvae. Stem-loop RT-PCR and Sanger sequencing confirmed its gut expression. Target prediction identified 146 candidate mRNAs, and dual-luciferase assays verified AcDorsal1 and AcARL4C as direct targets, significantly suppressing reporter activity (P < 0.01). During infection, ace-miR-3759-y was upregulated (P = 0.0008), whereas AcDorsal1 was downregulated (P = 0.0011). Inhibiting ace-miR-3759-y reduced its expression (P < 0.0001), relieved target repression, enhanced reactive oxygen species (ROS) accumulation (P = 0.0006), tended to increase antimicrobial peptide (AMP) gene expression, and decreased fungal ADM-B and chsD expression. Functionally, ace-miR-3759-y inhibition reduced cumulative mortality and chalkbrood incidence (both P < 0.0001), whereas AcARL4C silencing suppressed AMP genes and aggravated disease. These findings reveal a dual-target miRNA module and provide a potential RNAi-based target for chalkbrood control.
He Zang, Haimei Yue, Xiaoxue Fan et al.· Journal of Agricultural and...· 0 citations
Microsporidia rely extensively on host resources, yet how parasite-derived microRNAs coordinate infection remains poorly understood. Here, we investigated the function of nce-miR-12220, a miRNA identified in Nosema ceranae spores, during infection of Apis mellifera workers. Target prediction, dual-luciferase assays, and fluorescence in situ hybridization were combined with RNA interference and miRNA gain- and loss-of-function experiments. nce-miR-12220 interacted sequence-specifically with binding regions in ATP-A and γ-tubulin and was detected in infected honeybee midgut epithelial cells. Silencing either target gene reduced expression of the N. ceranae virulence-associated gene NcRBL and improved worker survival relative to the scramble control. In infected workers, nce-miR-12220 overexpression increased endogenous ATP-A and γ-tubulin transcript abundance, whereas inhibition produced the opposite effect. Overexpression also reduced expression of the Toll pathway-associated genes Cactus and dorsal and the antimicrobial peptide genes Defensin and Hymenoptaecin, increased N. ceranae spore load and sucrose consumption, and decreased midgut ATP content. Inhibition of nce-miR-12220 reversed these responses and reduced parasite burden. Survival after nce-miR-12220 manipulation changed in the predicted direction but did not reach statistical significance. Together, these findings identify nce-miR-12220 as a parasite-derived regulator that promotes N. ceranae proliferation while reshaping host immune and energetic responses, and suggest that this microRNA and its target network may provide candidates for controlling bee nosemosis.
Rui Guo, He Zang, Wenhua Xu et al.· PLoS Pathogens· 0 citations
