Multidrug resistance ABC transporter ortholog expression pattern across honey bee castes

Honey bees (Apis mellifera) are vital agricultural pollinators, sustaining billion-dollar industries such as almond production in the United States. By living in highly organized societies with a complex caste system, honey bees exhibit distinct roles and behaviors crucial for hive functioning. During the pollination season, the hive comprises three primary castes: workers, queens, and drones. During commercial pollination practices, hive members are exposed to xenobiotic chemicals, raising concerns about their collective hive health. Honey bees possess a sophisticated chemical defensome, which is comprised of metabolic pathways and transporters responsible for detoxification. Within the defensome, Phase 0 efflux transporters serve as the first line of defense against lipophilic compounds, preventing their entry into cells, while Phase III serves as the secondary control for elimination. Despite the importance of these transporters, their role in honey bee xenobiotic defense remains understudied. While studies have focused on metabolic enzymes like CYPS and their role in honey bee detoxification, research on ATP-binding cassette (ABC) transporters has primarily explored their involvement in insecticide resistance across other insect species. However, their significance in honey bee xenobiotic defense and the interplay across caste members remain poorly understood. This study investigated the relative expression profiles of 12 ABC transporter family members suspected to be involved in xenobiotic defense across honey bee castes (workers, queens, and drones) and life stages. Real-time PCR analysis quantified gene expression levels, shedding light on the contributions of ABC transporters to honey bee chemical detoxification.