Functional Characteristics of General Odorant Binding Proteins in the Sugarcane Borer (Tryporyza intacta)

Tryporyza intacta is a stem-boring pest that readily causes dead hearts in sugarcane seedlings and dead tops in mature plants, leading to large-scale yield reduction. Reverse chemical ecology studies of this pest contribute to its field biological control. During olfactory recognition, odor molecules are integrated by the olfactory nervous system after interacting with odorant-binding proteins (OBPs) and chemosensory proteins (CSPs), thereby regulating insect behavior.

Two novel full-length general odorant-binding protein (GOBP) genes were cloned from antennal tissues using reverse transcription PCR. Protein sequence analysis was conducted to determine sequence similarity and conserved structural features. The recombinant GOBP1-2 protein was expressed in Escherichia coli and purified via Ni-ion affinity chromatography. Fluorescence binding assays were performed to evaluate the binding affinities of GOBP1-2 with various volatile odorant molecules.

Protein sequence analysis revealed that the two identified GOBPs shared high sequence similarity with other insect GOBPs and contained the characteristic six-cysteine motif. Fluorescence binding assays demonstrated that GOBP1-2 proteins exhibited differential binding affinities to distinct volatile odorant molecules, indicating selective ligand recognition.

These findings suggest that GOBPs and effective volatile odorants likely play a functional role in the olfactory behavioral responses of this moth. This research provides valuable insights for developing field attractants targeting this sugar borer.