Dissecting the role of pheromone-binding protein 2 in courtship behavior of male Grapholita molesta moths.

For fruit-boring pests like Grapholita molesta, the courtship behavior of male moths is a crucial aspect that can be utilized for developing control methods. This study investigates the role of pheromone-binding proteins (PBPs) in the courtship behavior of male G. molesta moths, particularly how sex pheromone components affect PBP expression. We found that three GmolPBPs genes were mainly expressed in the antennae of adult males, with no expression in larvae or pupae. Notably, GmolPBP2 expression was significantly higher in males, while GmolPBP1 was more pronounced in females. Unmated males exposed to females or the sex pheromone component Z8-12:Ac showed marked upregulation of GmolPBPs expression. Using affinity chromatography, we purified GmolPBPs and confirmed their binding affinities. Especially for GmolPBP2, this protein had a high affinity for Z8-12:Ac and E8-12:Ac. RNA interference targeting GmolPBPs revealed that silencing GmolPBP2 significantly reduced male responses to sex pheromone components and courtship behavior towards females, while silencing GmolPBP1 and GmolPBP3 had no significant effects. These findings highlight the crucial role of GmolPBP2 in mediating male courtship behavior, emphasizing the importance of PBPs in pheromone communication and mating success in G. molesta.