A dose-response transcriptome of honey bee workers: characterizing gene expression across a large range of oxidative stress

Stress response in insects is often studied through single behaviors, traits, or genes to identify quantitative impacts of sublethal stress dosages. While this approach has been used to study stressors and beneficial treatments in honey bees, experimental designs rarely combine a range of doses with a large number of biological outcomes due to costs and/or feasibility. Using a cost-efficient Tag-seq approach, we create a dose response of the entire honey bee transcriptome to the oxidative stressor Paraquat, a herbicide that induces oxidative stress in a wide variety of organisms. Across 10 doses, we vary the stress X-fold and evaluate the physiological responses in 96 whole transcriptome profiles. This whole transcriptome strategy along with a large dose range allows us to obtain both a gene and process view of how honey bees, and potentially other insects, respond to dramatically varying levels of oxidative stress. We are able to identify key biological processes that underlie resistance to oxidative stress and also how the transcriptome appears in response to doses that result in certain death. This study paradigm could help as a general framework for testing other stressors or beneficial treatments both alone and in conjunction to understand stressor-stressor and stressor-treatment interactions and hopefully contribute to improving honey bee health in the future.