Comparative transcriptome analysis of hypopharyngeal glands from nurse and forager bees of Apis mellifera with the same age

Abstract

The hypoharyngeal glands (HGs) are the major organ for synthesizing and secreting royal jelly (RJ) in nurse honeybees. To eliminate the influence of age, we explored the molecular basis of RJ production by determining the morphology and protein content, and comprehensively comparing the transcriptome of HGs of age-matched nurses and foragers obtained from an established colony. Acinus area and total protein content of HGs in nurses were significantly increased compared with aged-matched foragers. RNA-seq analysis showed that 510 up-regulated genes in HGs of nurses, mainly enriched on translation, transcription, DNA replication, and energy metabolism, were associated with synthesis and secretion of RJ, suggesting that HGs of nurses might employ diverse strategies to drive RJ synthesis. Particularly, MRJP1, MRJP4, and MRJP5, the primary components of fresh RJ, were extremely higher in HGs of nurses than those in the corresponding age foragers. This study will provide considerable insight into the strategies employed by nurses for RJ secretion.