Odorant binding proteins (OBPs) are essential for insect olfaction. Lissorhoptrus oryzophilus (Coleoptera: Curculionidae), known as the rice water weevil, is a destructive pest of rice. In this study, rice volatiles were analyzed by gas chromatography-mass spectrometry (GC-MS), and ten rice volatiles were identified. Quantitative real-time PCR (qRT-PCR) analysis revealed that LoryOBP17 is highly expressed in the antennae. Fluorescence competitive binding assays demonstrated that LoryOBP17 exhibits strong binding affinity to 1-penten-3-ol and (E)-2-hexenal among the identified volatiles. 1-Penten-3-ol and (E)-2-hexenal (0.1 μg/μL) elicited strong EAG responses and significant behavioral attraction. After RNA interference (RNAi), EAG responses and behavioral attraction to 1-penten-3-ol and (E)-2-hexenal were significantly reduced. These results indicate that LoryOBP17 recognizes and binds these two host plant volatiles, suggesting its involvement in host odorant perception in RWW.
Wang et al. (Wed,) studied this question.