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
ABSTRACT 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.
Xiaoxue Fan, Kaiyao Zhang, Yun Yang et al.· Virulence· 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
Findings support a negative regulatory role of novel-miR0032-5p in CAT expression and indicate that lncRNA1386.1 participates in a candidate shared miRNA-responsive regulatory relationship.
Xiaoxue Fan, Nian Fan, Kunze Li et al.· Antioxidants· 0 citations