Binding Properties of Chemosensory Protein 1 to Plant Volatiles Guiding Nicotiana rustica Recognition in Helicoverpa armigera

Helicoverpa armigera is one of the most serious pests attacking tobacco around the world. Nicotiana rustica is widely used as a trap crop in the fields of Nicotiana tabacum in China. However, the chemical and molecular bases guiding N. rustica recognition in H. armigera are still unknown. In this study, we found 15 volatiles emitted from N. rustica induced EAG responses of H. armigera, while β-ocimene, α-pinene, and linalool were attractive to the moths in Y-tubes. Oviposition tests showed that H. armigera prefers to lay eggs on tobacco plants treated with β-ocimene and α-pinene. Further assays showed that an antenna-enriched chemosensory protein, HarmCSP1, binds robustly with β-ocimene, benzaldehyde, and (Z)-3-hexenyl acetate. Structural analyses revealed that several key amino acid residues are involved in ligand binding. This study increases the understanding of the chemosensory mechanism of H. armigera's recognition of N. rustica and provides the foundation for the design of attractants for H. armigera management.