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ARS Home » Pacific West Area » Tucson, Arizona » Honey Bee Research » Research » Publications at this Location » Publication #352055

Research Project: Determining the Impacts of Pesticide- and Nutrition-Induced Stress on Honey Bee Colony Growth and Survival

Location: Honey Bee Research

Title: Transcriptional response of honey bee to differential nutritional status and Nosema infection

Author
item Azzouz-olden, Farida - Kentucky State University
item Degrandi-hoffman, Gloria
item Hunt, Arthur - University Of Kentucky

Submitted to: BMC Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/13/2018
Publication Date: 8/22/2018
Citation: Azzouz-Olden, F., Hoffman, G.D., Hunt, A. 2018. Transcriptional response of honey bee to differential nutritional status and Nosema infection. BMC Genomics. 19:628.

Interpretive Summary: Honey bees encounter multiple environmental challenges including the combined effects of malnutrition and disease. Pollen is the healthiest nutrition source for bees, but when it not available, protein supplements such as BeePro and MegaBee, are used. We examined how feeding pollen and protein supplements shape transcription in the abdomen of the honey bee, and how transcription shifts with Nosema parasitism. Our analysis revealed that, compared with a diet of only sugar syrup, bees fed pollen, BeePro, and MegaBee showed a broad upregulation of metabolic processes. Most notably, pollen diet promoted an overexpression of vitellogenin that was not found in bees fed MegaBee or BeePro. A diet of only sugar syrup induced starvation response genes and elicited ‘adult behavior’, and developmental processes suggesting transition to foraging. Finally, bees fed only sugar syrup showed altered ‘circadian rhythm’, reflecting the possible role of this mechanism in the adaptation to nutritional stress. Nosema-infected bees fed pollen compared to sugar syrup upheld certain bioprocesses of uninfected bees. Poor nutritional status was more apparent when compared with pollen than BeePro or MegaBee. Nosema accentuated the effects of malnutrition as more starvation-response genes and stress response mechanisms were upregulated in Nosema infected bees fed sugar syrup than infected bees fed pollen. These results provide evidence of the superior nutritional value of pollen and the limitations of protein supplements in terms of promoting overall bee health, especially in the presence of a pathogen.

Technical Abstract: Bees are confronting several environmental challenges, including the intermingled effects of malnutrition and disease. Intuitively, pollen is the healthiest nutritional choice, however, commercial substitutes, such as BeePro and MegaBee, are widely used. Herein we examined how feeding natural and artificial diets shapes transcription in the abdomen of the honey bee, and how transcription shifts in combination with Nosema parasitism. Gene ontology enrichment revealed that, compared with poor diet (carbohydrates [C]), bees fed pollen (P>C), BeePro (B>C), and MegaBee (M>C) showed a broad upregulation of metabolic processes, especially lipids; however, pollen feeding promoted more functions, and superior proteolysis. The superiority of the pollen diet was also evident through the remarkable overexpression of vitellogenin in bees fed pollen instead of MegaBee or BeePro. Upregulation of bioprocesses under carbohydrate feeding compared to pollen (C>P) provided a clear poor nutritional status, uncovering stark expression changes that were slight or absent relatively to BeePro (C>B) or MegaBee (C>M). Poor diet feeding (C>P) induced starvation response genes and hippo signaling pathway, while it repressed growth through different mechanisms. Carbohydrate feeding (C>P) also elicited ‘adult behavior’, and developmental processes suggesting transition to foraging. Finally, it altered the ‘circadian rhythm’, reflecting the role of this mechanism in the adaptation to nutritional stress in mammals. Nosema-infected bees fed pollen compared to carbohydrates (PN>CN) upheld certain bioprocesses of uninfected bees (P>C). Poor nutritional status was more apparent against pollen (CN>PN) than BeePro (CN>BN) or MegaBee (CN>MN). Nosema accentuated the effects of malnutrition since more starvation-response genes and stress response mechanisms were upregulated in CN>PN compared to C>P. The bioprocess ‘Macromolecular complex assembly’ was also enriched in CN>PN, and involved genes associated with human HIV and/or influenza, thus providing potential candidates for bee-Nosema interactions. Finally, the enzyme Duox emerged as essential for guts defense in bees, similarly to Drosophila. These results provide evidence of the superior nutritional status of bees fed pollen instead of artificial substitutes in terms of overall health, especially in the presence of a pathogen.