A Pheromone-Dominant Odorant-Binding Protein Mediates Mating and Host Volatile Perception in Anomala corpulenta

The scarab beetle Anomala corpulenta is a significant agricultural pest, causing crop damage through adult feeding and larval root destruction. Targeting its sex pheromone system provides a promising eco-friendly pest control strategy. Pheromone-binding proteins (PBPs) are essential in the process of pheromone detection. We functionally characterized AcorOBP4 and AcorOBP15, which are predominantly expressed in male antennae. AcorOBP15 exhibited the highest binding affinity toward the sex pheromone (R)-japonilure, while showing comparatively weaker binding to host plant volatiles, suggesting a pheromone-dominant role in odorant detection. RNAi knockdown of AcorOBP15 significantly reduced the electrophysiological and behavioral responses of male beetles to (R)-japonilure. Molecular docking revealed that AcorOBP15 interacts with (R)-japonilure through a combination of hydrophobic interactions and a single hydrogen bond. Finally, mutagenesis of the hydrogen-bonding site Ser121 markedly reduced pheromone binding affinity. These findings highlight AcorOBP15 as a pheromone-dominant, multifunctional PBP that may contribute to the coordinated perception of mating and host-related cues at the peripheral olfactory level.