Response to Enantiomers of (Z3Z9)-6,7-Epoxy-Octadecadiene, Sex Pheromone Component of Ectropis obliqua Prout (Lepidoptera: Geometridae): Electroantennagram Test, Field Trapping, and in Silico Study

Limited information on sex pheromone recognition by tea moths, Ectropis obliqua Prout (Lepidoptera: Geometridae), exists for this economically important pest of tea (Camellia sinensis L.; Theaceae). Pheromone binding proteins (PBPs), a sub-family of odorant-binding proteins, control transportation of pheromone molecules that may contribute to the discrimination of sex pheromone components. It has been reported previously that EoblPBP1 gene (a pheromone binding protein of E. obliqua) is highly expressed in antennae of the male moth. Based on this information, a reliable model of EoblPBP1 was constructed by homology modeling using the enantiomers of Z3Z9-6,7-epo-18:Hy docked into the hydrophobic cavity of the model. Docking results suggested similar binding affinities of this enantiomer to EoblPBP1. However, electroantennogram and field trapping experiments of E. obliqua males revealed that response to Z3Z9-(6S,7R)-epo-18:Hy was significantly greater than the opposite configuration, and suggested enantiomeric discrimination could occur on sex pheromone receptors of this species of tea moth.