Identification of β-ionone as an oviposition preference cue in Spodoptera litura using SlitPBP3-based reverse...

Screening and identifying compounds that modulate oviposition by female Spodoptera litura moths is a promising strategy for the selective management of this pest. Reverse chemical ecology provides an efficient and target-oriented approach for identifying bioactive semiochemicals by exploiting the functionally relevant olfactory binding proteins.

Scanning electron microscopy revealed the presence of multiple types of sensilla on the ovipositor of female S. litura, providing morphological support for the selection of ovipositor-expressed olfactory genes as screening targets. In the present study, we used SlitPBP3, an olfactory gene expressed in the ovipositor of female S. litura during the calling stage, as a molecular target for screening oviposition-related compounds. Structure-based virtual screening combined with fluorescence competitive binding assays demonstrated that SlitPBP3 showed preferential binding to β-ionone among the tested compounds. Site-directed mutagenesis further revealed that residues F12 and F118 are critical for the interaction between SlitPBP3 and β-ionone. Functional assays showed that RNA interference-mediated silencing of SlitPBP3 significantly reduced the oviposition preference index of female moths for β-ionone-treated substrates. Notably, female moths continued to preferentially oviposit on β-ionone-treated substrates even after antennal ablation, indicating that chemosensory perception during oviposition can occur independently of antennal input.

The present study establishes SlitPBP3 as a practical screening target within a reverse chemical ecology framework and identifies β-ionone as an oviposition-stimulatory cue with potential value for developing female-oriented behavioral management strategies against S. litura. © 2026 Society of Chemical Industry.