Identification\nof a Soybean Volatile Attractive for <i>Riptortus pedestris</i> Using Reverse Chemical Ecology Approach

The bean bug Riptortus pedestris is a major soybean pest and a cause of the stay-green symptoms.\nHowever, the molecular mechanisms underlying its olfaction-mediated\nhost-seeking behavior remain unclear. In this study, we compared the\nantennae transcriptomes of starved and nonstarved adult R. pedestris, identifying four differentially expressed\nodorant receptor (OR) genes. Among these, RpedOR13 showed a strong\nresponse to the host volatile 2-phenylethanol (2-PE) in <i>Xenopus</i> oocyte assays, while electroantennography and behavioral tests confirmed\n2-PE as an effective attractant. Next, phylogenetic analysis identified\nRpedOR72b as a paralog of RpedOR13, with subsequent <i>Xenopus</i> oocyte assays confirming its specific response to 2-PE. Additionally,\nRNA interference experiments highlighted the crucial role of <i>RpedOR72b</i> in detecting 2-PE. Taken together, these findings\nprovide new insights into the molecular mechanisms of host-seeking\nbehavior in R. pedestris and highlight\nthe successful application of reverse chemical ecology in OR-based\nscreening of bioactive compounds.