Next-generation small RNA sequencing for microRNAs profiling in Apis mellifera: comparison between nurses and foragers

MicroRNAs (miRNAs) are endogenous small non-coding RNAs regulating gene expression in animals and plants. To find some differentially expressed miRNAs that may be associated with age-dependent behavioural changes in honey bees (Apis mellifera), we applied next-generation high-throughput sequencing technology to detect small RNAs in nurses and foragers. Our results showed that both nurses and foragers had a complicated small RNA population, and the length of small RNAs varied, 22 nucleotides being the predominant length. Combining deep sequencing and bioinformatic analysis, we discovered that nine known miRNAs were significantly different between nurses and foragers (P < 0.01; absolute value of fold-change =1). Some of their target genes were related to neural function. Moreover, 67 novel miRNAs were identified in nurses and foragers. Ame-miR-31a and ame-miR-13b were further validated using quantitative reverse-transcription PCR assays. The present study provides new information on the miRNA abundance of honey bees, and enhances our understanding of miRNA function in the regulation of honey bee development.