Screening of Attractants for Male Spodoptera frugiperda Based on the Interaction between Odorant-Binding Protein 20 and Host Volatiles

Odorant-binding protein as an important olfactory gene is often used as a molecular target for developing insect attractants. Here, we found that SfruOBP20 of Spodoptera frugiperda is significantly highly expressed in male antennae. Prokaryotic expression system and fluorescence competitive binding assays further revealed that SfruOBP20 binds to 13 maize volatiles. Modeling and molecular docking results revealed six conserved binding sites that may serve as key recognition sites. Subsequently, we found that six volatiles with high antennal electrophysiological response values can also attract male moths, among which 1-octen-3-ol and decanal can function at low concentrations, indicating that these six volatiles could potentially be developed as male moth attractants. This experiment not only enables us to better understand the mechanism by which the S. frugiperda recognizes odorants but also provides a foundation for the development of green and efficient attractants.