Author
WANG, YING - Arizona State University | |
Brent, Colin | |
FENNERN, ERIN - Arizona State University | |
AMDAM, GRO - Arizona State University |
Submitted to: PLoS Genetics
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 5/7/2012 Publication Date: 6/28/2012 Citation: Wang, Y., Brent, C.S., Fennern, E., Amdam, G.V. 2012. Gustatory perception and fat body energy metabolism are jointly affected by vitellogenin and juvenile hormone in honey bees. PLoS Genetics. 8(6):e1002779. Interpretive Summary: Honey bees (Apis mellifera) provide a system for studying social and food-related behavior. A caste of workers performs age-related tasks: young bees (nurses) usually feed the brood inside the nest while older bees (foragers) forage outside for pollen, a source of fats and protein, or nectar, a carbohydrate source. The workers’ transition from nursing to foraging and their foraging preferences is correlated with changes in taste perception, the expression of genes associated with metabolism, and circulating levels of vitellogenin (Vg) and juvenile hormone (JH). However, our understanding of how these traits are connected is incomplete. To elucidate these connections we used RNA interference (RNAi) to create single and double knockdowns of the genes ultraspiracle (usp) and vg, which encode a putative JH receptor and Vg, respectively. The double knockdown elevated levels of taste perception, JH, and blood sugars. We also observed changes in the expression of metabolic genes. Collectively, the results suggest that the Vg-JH regulatory apparatus controls changes in carbohydrate metabolism but not lipid metabolism, and also activates gene complexes well-known to be involved in taste perception. Technical Abstract: Honey bees (Apis mellifera) provide a system for studying social and food-related behavior. A caste of workers performs age-related tasks: young bees (nurses) usually feed the brood inside the nest while older bees (foragers) forage outside for pollen, a protein/lipid source, or nectar, a carbohydrate source. The workers’ transition from nursing to foraging and their foraging preferences correlate with differences in gustatory perception, metabolic gene expression and endocrine physiology including the endocrine factors vitellogenin (Vg) and juvenile hormone (JH). However, the understanding of connections between social behavior, energy metabolism and endocrine factors is incomplete. We used RNA interference (RNAi) to perturb the gene network of Vg and JH to learn more about these connections through effects on gustation, gene transcripts and physiology. The RNAi perturbation was achieved by single and double knockdown of the genes ultraspiracle (usp) and vg, which encode a putative JH receptor/response element and Vg, respectively. The double knockdown released elevated levels of gustatory perception, hemolymph glucose, trehalose and JH. We also observed transcriptional responses in insulin like peptide 1 (ilp1), the adipokinetic hormone receptor (AKHR) and cGMP-dependent protein kinase (PKG, or ‘foraging gene’ Amfor). Our study demonstrates that the Vg-JH regulatory module controls changes in carbohydrate metabolism but not lipid metabolism, when worker bees shift from nursing to foraging. The module is also placed upstream of ilp1, AKHR, and PKG for the first time. As insulin, adipokinetic hormone (AKH) and PKG pathways influence gustation in many animals, we suggest that honey bees show conserved connections between energy metabolism and gustatory perception. |