An odorant receptor-derived peptide biosensor for monitoring the occurrence of Hyphantria cunea larvae by recognizing herbivore-induced plant volatile

Abstract

The release of volatile β-ocimene induced by Hyphantria cunea (H. cunea) larvae in mulberry is an important olfactory cue for host localization of H. cunea adults. In the present study, we demonstrated that H. cunea adults sensitively recognized β-ocimene through a Y-tube test and single sensillum recording (SSR) experiments. Through a combination of homology alignment, tissue profile expression, and transgenic Drosophila SSR assays, HcunOR31 was identified as the specific odorant receptor for β-ocimene in H. cunea. We used transmembrane domain prediction, molecular docking, and peptide synthesis techniques to fabricate three odorant receptor-derived peptide sensors (ORP-sensors) that had the potential to monitor β-ocimene. Among these three, the best sensitivity and specificity to β-ocimene were demonstrated by the ORP3-sensor. Further experimentation revealed that the detection limit of the ORP3-sensor could be as low as one larva feeding on mulberry leaves; in addition, the sensor showed a larger resistance change with the increase in the number of larvae. These findings address the application value of insect olfactory mechanisms and provide an entry point for real-time monitoring of the early occurrence of H. cunea larvae in woodlands.