Decoding the Olfactory Deception: Molecular Basis into Chilo suppressalis’ Recognition of the Lethal Trap Plant Vetiveria zizanioides

The striped stem borer ( Chilo suppressalis ), a devastating rice ( Oryza sativa L.) pest, exhibits a paradoxical oviposition preference for vetiver grass ( Vetiveria zizanioides L.), a nonhost plant causing complete larval mortality. To elucidate the molecular basis of this maladaptive attraction, we investigated the olfactory mechanisms driving C. suppressalis ’ recognition of vetiver volatiles. Experimental results demonstrated that C. suppressalis exhibited a significant oviposition preference for vetiver over its natural host rice, despite the developmental incompatibility of offspring on the nonhost plant. Through GC-MS and GC-EAD analyses, durene, camphor, α-cedrene, and phytone were identified as vetiver-associated antenna responding volatile compounds. Behavioral assays confirmed that these compounds not only mediate oviposition attraction in females but also exhibit synergistic effects when combined with sex pheromone. Electrophysiological analyses revealed that three odorant receptors (OR1, OR20, and OR21) are responsible for detecting these four compounds. Structural modeling, molecular docking, and site-directed mutagenesis further delineated the molecular basis of ligand–receptor interactions, pinpointing specific residues essential for binding activity. Our study provides a molecular blueprint for engineering receptor-specific semiochemicals to disrupt host-seeking behaviors, advancing precision field push–pull strategies.