Co-incubation of dsRNA reduces proportion of viable spores of Ascosphaera apis , a honey bee fungal pathogen

There are viral, fungal, bacterial and trypanosomal pathogens that negatively impact the individual and superorganismal health of the western honey bee. One fungal pathogen, Ascosphaera apis, affects larvae and is the etiological agent of the disease chalkbrood. A previous genome analysis of A. apis revealed that its genome encodes for RNA interference genes, similar to other fungi and eukaryotes. Here, we examined whether A. apis-targeting double-stranded RNA species could disrupt the germination of A. apis. We observed that when spores were co-incubated with A. apis-targeting dsRNA, fewer spores were activated for germination, suggesting an uptake of exogenous genetic material at the very onset of germination and consequent damage to essential transcripts needed for germination. Overall, these results indicate that the causative agent of chalkbrood disease can be successfully targeted using an RNAi-based strategy.