Identification of Behaviorally Active Odorants for Adult <i>Chilo sacchariphagus</i> Based on the Binding Properties of Odorant-Binding Proteins toward Host Volatiles

<i>Chilo sacchariphagus</i> is the key pest of sugar cane. Due to the difficulty associated with pesticide application in middle and late growth stages of sugar cane, the use of odorant attractants is a beneficial alternative to pesticides. Odorant-binding proteins (OBPs) in the insect olfactory system represent excellent targets for screening odorant attractants. Here, we identified 12 <i>OBPs</i> from the head transcriptome of <i>C. sacchariphagus</i> adults, with four <i>OBPs</i> (<i>CsacOBP1</i>/2/5/12) highly enriched in adult antennae. Ligand-binding assays for the four CsacOBPs showed that they can bind with 10 of the 30 host volatiles tested. Behavioral assays revealed that (+)-cedrol and 1-hexadecanol from the 10 compounds can attract the moths of both sexes. Protein-ligand interaction analyses identified five key amino acid residues involved in CsacOBPs' binding to (+)-cedrol and 1-hexadecanol. These findings have enhanced our molecular understanding of the host plant selection in <i>C. sacchariphagus</i> and have facilitated the development of attractants for <i>C. sacchariphagus</i>.