A Chemosensory Protein Detects Antifeedant in Locust ().

Chemosensory system is vitally important for animals to select food. Antifeedants that herbivores encounter can interfere with feeding behavior and exert physiological effects. Few studies have assessed the molecular mechanisms underlying the chemoreception of antifeedants. In this study, we demonstrated that a chemosensory protein (CSP) in is involved in detecting an antifeedant. This CSP, EST6 (GenBank Acc. No. AJ973420), we named as CSPIII, expressed in sensory organs where chemosensilla are widely distributed. Fluorescent binding experiments indicated that CSPIII exhibits high binding affinity to α-amylcinnamaldehyde (AMCAL), a natural compound from non-host plant. This compound was subsequently demonstrated to be an effective antifeedant to locusts in feeding bioassay. By injection of double-stranded RNA (dsRNA) of CSPIII, we generated CSPIII knockdown locusts. The feeding behaviour assays demonstrated that the CSPIII knockdown locusts had reduced sensitivity to the antifeedant but showed no changes in their physiological development or food consumption. Therefore, we inferred that this chemosensory protein is involved in antifeedant detection.