In-depth Proteome of the Hypopharyngeal Glands of Honeybee Workers Reveals Highly Activated Protein and Energy Metabolism in Priming the Secretion of Royal Jelly*

Abstract

The hitherto depth proteomes of the hypopharyngeal glands (HGs) across the adult life of two stocks of honeybees with low (ITBs) and high royal jelly production (RJBs) uncover the molecular landscapes of the gland ontogeny and activity to match with gland age-specific tasks. Pathways involved in protein and energy metabolism are induced in HGs of RJB nurse bees to enhance royal jelly (RJ) secretion relative to ITBs. Our finding gains a novel mechanistic insight of the augment RJ-output in RJBs.

Graphical Abstract

Highlights

• In-depth proteome underpins the gland ontogeny and age-specific activity of the HGs.

• The well-developed acini in the HGs of NBs promote the RJ secretary activities.

• The enhanced protein and energy metabolism in the HGs boost the stronger RJ secretion of RJBs.

Abstract

Royal jelly (RJ) is a secretion of the hypopharyngeal glands (HGs) of honeybee workers. High royal jelly producing bees (RJBs), a stock of honeybees selected from Italian bees (ITBs), have developed a stronger ability to produce RJ than ITBs. However, the mechanism underpinning the high RJ-producing performance in RJBs is still poorly understood. We have comprehensively characterized and compared the proteome across the life span of worker bees between the ITBs and RJBs. Our data uncover distinct molecular landscapes that regulate the gland ontogeny and activity corresponding with age-specific tasks. Nurse bees (NBs) have a well-developed acini morphology and cytoskeleton of secretory cells in HGs to prime the gland activities of RJ secretion. In RJB NBs, pathways involved in protein synthesis and energy metabolism are functionally induced to cement the enhanced RJ secretion compared with ITBs. In behavior-manipulated RJB NBs, the strongly expressed proteins implicated in protein synthesis and energy metabolism further demonstrate their critical roles in the regulation of RJ secretion. Our findings provide a novel understanding of the mechanism consolidating the high RJ-output in RJBs.