Spodoptera frugiperda is a global pest that shows distinct preferences between maize and rice hosts. Concerning the prevailing S. frugiperda corn strains in China, we identified five maize-specific volatiles through GC-MS analysis of volatiles from maize and rice seedlings, in which benzothiazole and nonadecane were confirmed as key volatiles mediating attractants for female moths. Then, we screened for candidate odorant receptors (ORs) by analyzing differentially expressed genes between the moths exposed and unexposed to the active volatiles. Furthermore, we revealed via a Xenopus oocyte system that OR58 is narrowly tuned to benzothiazole, while OR25 exhibits a broader ligand spectrum with weak response to benzothiazole. Finally, molecular docking demonstrated OR58 and OR25 bind benzothiazole via hydrogen bonds at Thr307 and Trp157 residues, respectively, explaining their different selectivity patterns. These results provide molecular insights into host-plant preference mechanisms in S. frugiperda and identify potential targets for developing novel pest management approaches.
Keywords: DREAM; benzothiazole; corn strain; fall armyworm; host plant; nonadecane.