Targeting Olfaction for Control: OR17 and Its Ligand E-β-Caryophyllene Contribute to Host Location in Phthorimaea absoluta

Odorant receptors (ORs) of phytophagous insects mediate detection and discrimination of plant volatiles for host location and oviposition. Using the reverse chemical ecology approach, we identified host-related odorants and receptors in Phthorimaea absoluta. Molecular docking identified limonene, α-terpinene, and E-β-caryophyllene as putative ligands of OR9, OR6, and OR17, respectively. All three compounds elicited significant antennal responses in both sexes, with stronger responses in females. In Y-tube assays, E-β-caryophyllene attracted females, and a ternary blend (5:3:2) elicited significantly greater attraction than individual compounds. This female-biased attraction persisted across 72 h cage assays and for at least 18 days in a greenhouse. PabsOR17 silencing significantly reduced female behavioral responses to E-β-caryophyllene. These findings support the contribution of OR17-mediated E-β-caryophyllene detection to female host location, providing a potential molecular target for female-oriented behavioral disruption and a reverse chemical ecology framework for semiochemical-based pest management.