This work presents the first identification of putative odorant-binding proteins (OBPs) from a member of the Pentatomidae, i.e. the brown stink bug Euschistus heros (Fabricius), an important pest of soybean in Brazil. Antennae from both sexes of E. heros adults (12 days old and unmated) were used to construct a cDNA library, from which two transcripts encoding putative E. heros OBPs (EherOBPs) were identified. The expression levels of EherOBP1 and EherOBP2 were found to be higher in male antennae than in female and there was difference in expression in legs, wings, and abdomens of the two sexes. The histolocalization of EherOBP1 and EherOBP2 transcripts in antennae also showed a sexual dimorphism in the chemoreception system, with different expression sites in the antennal segments between males and females, occurring predominantly at the base of the sensillum. The implications of these findings for stink bug chemoreception are discussed.
Keywords: Antennae; amphipathic proteins; chemoreception; olfaction; semiochemicals; sensillum.