Task-related differential expression of four cytochrome P450 genes in honeybee appendages

In insects, cytochrome P450 monooxygenases (P450s) contribute to phytochemical and pheromone clearance in chemoreception and xenobiotic detoxification in food processing. In eusocial species, P450 expression varies with anatomy and age-related behaviour. Adult honeybees (Apis mellifera) possess appendages differentially equipped for chemoreception; antennae and prothoracic and mesothoracic legs assess food and pheromone signals whereas metathoracic legs transport pollen over long distances. Newly eclosed bees and nurses remain in the hive and neither gather nor process food, whereas foragers collect pollen and nectar, thereby encountering phytochemicals. To understand the functions of cytochrome P450, family 4, subfamily G, polypeptide 11 (CYP4G11) in the honeybee genome, we compared its expression relative to worker age and task to expression of cytochrome P450, family 9, subfamily Q, polypeptides (CYP9Qs) known to metabolize xenobiotics. That CYP4G11 is highly expressed in forager antennae and legs, with highest expression in prothoracic and mesothoracic legs, is consistent with chemosensory perception, whereas weak expression of CYP4G11 in nurses suggests that it may process primarily exogenous rather than endogenous chemical signals. By contrast, and consistent with xenobiotic detoxification, the three CYP9Q transcripts were almost undetectable in newly eclosed workers and highest in foragers, with maximal expression in the metathoracic legs that closely contact pollen phytochemicals. These CYP4G11 expression patterns suggest a role in processing environmental signals, particularly those associated with food.