Molecular characterization and functional differentiation of three pheromone-binding proteins from Tryporyza intacta

Insect pheromone-binding proteins (PBPs) have been proposed to capture and transport hydrophobic sex pheromone components emitted by con-specific insects to pheromone receptors in the hemolymph of male antennal sensilla. In this study, field trapping results indicate that a mixture of E11-16: Ald and Z11-16: Ald can effectively attract a great number of male Tryporyza intacta. Real-time PCR results suggest that the transcript levels of three TintPBP1-3 genes are mainly expressed in the adult antennae. Fluorescence competitive binding experiments show that TintPBP1-3 proteins have great binding affinities to their major sex pheromones. Moreover, TintPBPs clearly cannot bind to other four kinds of sex pheromone components released by another sugarcane borer, Chilo venosatus and Chilo infuscatellu, which have the same host plant and live in similar habitats like T. intacta. The molecular docking results demonstrate that six amino acid residues of the three TintPBPs are crucial for the specific perception of the sex pheromone components. These results will provide a foundation for the development of novel sex pheromone analogues and blocking agents for biological control of sugarcane pests, improving their efficient monitoring and integrated management strategies in the sugarcane field.