Functional Characterization of a Candidate Sex Pheromone Receptor AlinOR33 Involved in the Chemoreception of .

Sex pheromones are deemed to play a significant role in sexual communication of most insects. Although many sex pheromone components in mirid bugs have been identified, the roles of odorant receptors in sex pheromone perception in (Hemiptera: Miridae) remain unknown so far. Here, AlinOR33, a candidate sex pheromone receptor in was functionally characterized. Phylogenetic analysis showed that AlinOR33 clustered with the sex pheromone receptor AlucOR4 from. Quantitative real-time PCR measurement revealed that the expression of increased gradually from nymph to adult stage and reached its peak in the antennae of 3-day-old mated male bugs. The subsequent hybridization demonstrated that 33 was mainly expressed in sensilla trichoid on the antennae of . In the two-electrode voltage clamp recordings, AlinOR33/AlinOrco was specifically tuned to four sex pheromone components including butyl butyrate, hexyl hexanoate, -2-hexenyl butyrate and hexyl butyrate, and especially most sensitive to the major component -2-hexenyl butyrate. After ds injection, the electroantennogram responses of males to four sex pheromone components were reduced significantly (∼50%). Compared to control bugs, ds-injected male bugs almost lost behavioral preference for -2-hexenyl butyrate. Furthermore, the wingbeat frequency of ds-injected male bugs notably declined. Therefore, we conclude that as a candidate sex pheromone receptor, AlinOR33 plays essential roles in the sexual behavior of .