The Odorant-Binding Protein Gene obp11 Shows Different Spatiotemporal Roles in the Olfactory System of Apis mellifera ligustica and Apis cerana cerana

Abstract

Odorant-binding proteins participate in the olfactory system of the honeybee. Apis mellifera ligustica and Apis cerana cerana are species of honeybee that have different biologic functions. The two species have diversified olfactory systems, with A. cerana displaying sensitive olfactory involvement in collecting nectar and pollen from small plants; and A. mellifera collecting from large nectariferous plants. We hypothesized that, given this difference in biologic activity, the gene obp11 of A. mellifera and A. cerana may show different olfactory expression patterns. We cloned and sequenced the obp11 genes from A. mellifera (Amobp11) and A. cerana (Acobp11). Using quantitative real-time PCR, we demonstrated that nurse workers, which have the highest olfactory sensitivity in the A. mellifera hive, have the highest expression of Amobp11; whereas 1-day-emerged workers, which have lowest olfactory sensitivity, have correspondingly low expression. However, the highest expression of Acobp11 is observed for foragers, which display the highest olfactory sensitivity in the A. cerana population. The OBP11 protein from the two species is highly conserved, with an apparent molecular weight and predicted extracellular localization that is similar to other OBP proteins. The expression of the obp11 gene in A. mellifera and A. cerana correlates with the different roles of the olfactory system for the two different species. These findings support the critical role of odorant-binding proteins in the Apis olfactory system

Keywords

• odorant-binding protein
• olfactory
• Apis