Identification and functional characterization of female antennae-biased odorant receptor 23 involved in acetophenone detection of the Indian meal moth Plodia interpunctella

The Indian meal moth, Plodia interpunctella (Lepidoptera: Pyralidae), a globally distributed storage pest, relies on odors that are emitted from stored foods to select a suitable substrate for oviposition. However, the molecular mechanism underlying the chemical communication between P. interpunctella and its host remains elusive. In this study, 130 chemosensory genes were identified from the transcriptomes of 7 P. interpunctella tissues, and the quantitative expression levels of all 56 P. interpunctella odorant receptor genes (PintORs) were validated using real-time quantitative polymerase chain reaction. The functional characteristics of 5 PintORs with female antennae-biased expression were investigated using 2-electrode voltage clamp recordings in Xenopus laevis oocytes. PintOR23 was found to be specifically tuned to acetophenone. Acetophenone could elicit a significant electrophysiological response and only attracted mated females when compared with males and virgin females. In addition, molecular docking predicted that the hydrogen bonding sites, TRP-335 and ALA-167, might play key roles in the binding of PintOR23 to acetophenone. Our study provides valuable insights into the olfactory mechanism of oviposition substrate detection and localization in P. interpunctella and points toward the possibility of developing eco-friendly odorant agents to control pests of stored products.