Molecular characterization, expression profiling, and binding properties of odorant binding protein genes in the whitebacked planthopper, Sogatella furcifera.

The whitebacked planthopper (WBPH) Sogatella furcifera is a notorious rice pest in Asia that utilizes chemoreception to help in locating and selecting host plants. In this study, we used a transcriptomic approach, based on the WBPH transcriptome, to identify genes encoding for proteins exhibiting OBP-like features. We discovered 12 important chemosensory genes, termed odorant binding protein (OBP) fragments. Subsequently, the entire open reading frames of these putative OBPs were obtained by RACE. The genes were classified into three groups of OBPs, eight "Classic OBPs", three "Plus-C OBPs", and one "Atypical OBP". The expression profiles of these 12 genes were investigated by real-time qPCR in different tissues (antennae, mouthparts, heads (without antennae and mouthparts), legs, and remaining bodies). Results revealed distinct tissue expression patterns of these OBPs, indicating their diverse functions in this species. Of note, SfurOBP2 and SfurOBP11 were the two highest expressing OBPs in antennae. We next used ligand-binding experiments to measure their binding spectrum in vitro. Results revealed that purified recombinant SfurOBP2 and SfurOBP11 bound several rice plant volatiles. Taken together, these findings will be helpful for determining the potential physiological functions of WBPH OBPs, which in turn may help to discover new targets for behavioral antagonists for use as control strategies.