Fecha de publicación: -- Fuente: PubMed "apis cerana" J Invertebr Pathol. 2026 Oct 29;220:108780. doi: 10.1016/j.jip.2026.108780. Online ahead of print.ABSTRACTMicroRNAs (miRNAs) play a critical role in the immune regulation of Apis cerana larvae infected by Ascosphaera apis, which is the pathogenic fungus causing chalkbrood disease. This study found that miRNA ace-miR-3720-x was significantly upregulated in the midgut of larvae infected with A. apis. The dual luciferase reporter assay confirmed that ace-miR-3720-x directly targeted the 3'UTR of Acβ-GBP, thereby negatively regulating its expression. Acβ-GBP is a pattern recognition receptor that participates in activating the Toll pathway and inducing the expression of antimicrobial peptides. Inhibition of ace-miR-3720-x resulted in marked upregulation of Acβ-GBP expression, thereby upregulating the expression of critical antimicrobial peptide genes and phenoloxidase cascade genes at the late phase of infection. Furthermore, inhibition of ace-miR-3720-x significantly reduced larval mortality and the incidence of chalkbrood disease; the expression of the A. apis virulence factor genes (ADM-B and chsD) was also decreased. Our findings indicate that ace-miR-3720-x functions as a negative regulator of antifungal immunity in honeybees, and attenuates host resistance by suppressing Acβ-GBP-mediated immune responses. ace-miR-3720-x may serve as a potential molecular target for the control of chalkbrood disease and for resistance breeding in honeybees.PMID:42957157 | DOI:10.1016/j.jip.2026.108780