Meeting Abstract
Global declines in honey bees have been linked to the widespread use of pesticides. Sublethal doses of the neonicotinoid imidacloprid have been shown to cause physiological and behavioral changes that negatively impact hive health. Work in our laboratory has shown that bees fed sublethal doses of the neonicotinoid pesticide imidacloprid displayed impaired motor responses and elevated levels of the cellular stress protein HSC70 and superoxide dismutase (SOD), an indicator of oxidative stress. The goal of this research was to determine how sub-lethal doses of the neonicotinoid imidacloprid alter gene expression and cellular pathways. We investigated the effects of the 1/20th of the LD50 dose of imidacloprid (18 ng/bee) on the transcriptome. Bees were assigned to a control group (1.5 M sucrose) or an imidacloprid treatment group (0.9 ng/bee) and heads were excised at Time 0 h or Time 4 h. Bee brains were dissected over dry ice and RNA was isolated. Genome-wide RNA sequencing analysis was conducted to identify altered gene expression patterns in the treatment group. Of the 11,000 genes sequenced, 30% were differentially expressed. Altered cellular functions were determined using functional clustering analysis in DAVID and KEGG pathway analysis. The expression of genes in the peroxisome pathway were altered, supporting our previous work showing elevated SOD and cellular stress responses following imidacloprid treatment. Additionally, the FOXO Signaling Pathway differed between the treatment and the control groups. Our results also indicate that imidacloprid has a potential broader impact on other cellular processes, including signal transduction and metabolism.
