Molecular characterization and volatile binding properties of pheromone binding proteins and general odorant binding proteins in Conogethes pinicolalis (Lepidoptera: Crambidae).

Conogethes pinicolalis (Lepidoptera: Crambidae), a major pine pest, possesses a sensitive olfactory system to locate its host. Pheromone binding proteins (PBPs) and general odorant binding proteins (GOBPs) are two types of proteins involved in the process. In this work, we used phylogenetic analysis, gene expression, fluorescence competitive binding assay, and molecular docking to characterize PBPs and GOBPs in C. pinicolalis. The phylogenetic unrooted tree revealed the C. pinicolalis GOBPs and PBPs amino acid sequences showed very close relation with Conogethes punctiferalis (yellow peach moth). Meanwhile, both the PBPs and GOBPs were specifically expressed in the antennae. Binding affinities of PBPs and GOBPs to 19 volatile compounds were tested. PBP2 shows the strongest binding to E10-16: Ald with a Ki value of 0.28/1.66 μM; GOBP1 to Z10-16:Ald with a Ki value of 3.11/4.24 μM. Furthermore, molecular docking reveals potential active sites in PBP2 and GOBP1 to interact with most of the tested volatiles. Finally, we demonstrate that PBP2 and GOBP1 are the dominant genes in their respective families using several different assays. In conclusion, PBP2 and GOBP1 genes may play similar roles in detecting and transporting sex pheromones and host plant volatiles in C. pinicolalis.