Diet-derived transmission of MicroRNAs from host plant into honey bee Midgut

Background MicroRNA (miRNA) is a class of small noncoding RNAs, which targets on thousands of mRNA and thus plays important roles in many biological processes. It has been reported that miRNA has cross-species regulation functions between parasitoid-host, or plant-animal, etc. For example, several plant miRNAs enter into the honey bees and regulate gene expression. However, whether cross-species regulation function of miRNAs is a universal mechanism remains a debate question. Results We have evaluated transmission of miRNAs from sunflower and sedr plants into the midgut of honey bee using RNA-Seq analyses complemented with confirmation by RT-qPCR. The results showed that at least 11 plant miRNAs were found in the midgut of honey bee feeding by sunflower and sedr pollen. Among which, nine miRNAs, including miR-30d, miR-143, miR-148a, miR-21, let-7 g, miR-26a, miR-126, miR-27a, and miR-203, were shared between the sunflower- and sedr-fed honey bees, suggesting they might have essential roles in plant-insect interactions. Moreover, existence of these co-shared miRNAs presents a strong evidence to support the successful transmission of miRNAs into the midgut of the insect. In total, 121 honeybee mRNAs were predicted to be the target of these 11 plant-derived miRNAs. Interestingly, a sedr-derived miRNA, miR-206, targets on 53 honeybee genes. Kyoto Encyclopedia of Genes and Genome (KEGG) analyses showed that these target genes are significantly involved in hippo signaling pathway-fly, Wnt signaling pathway, and N-Glycan biosynthesis. Conclusions In summary, these results provide evidence of cross-species regulation function of miRNA between honeybee and flowering host plants, extending our understanding of the molecular interactions between plants and animals.

Automated summary

The study found evidence of cross-species regulation function of miRNA between honeybees and flowering host plants by demonstrating the transmission of plant miRNAs into the midgut of honey bees feeding on sunflower and sedr pollen. Specifically, 11 plant miRNAs were identified in the midgut, with 9 miRNAs shared between sunflower- and sedr-fed honeybees, indicating potential essential roles in plant-insect interactions. Furthermore, the study predicted 121 honeybee mRNAs as targets of these plant-derived miRNAs, with implications in various biological pathways such as hippo signaling and Wnt signaling.