Abstract

Simple SummaryOphraella communaLesage is a specific biological control agent of the invasive weedAmbrosia artemisiifoliaL. Understanding the molecular mechanism by whichO. communarecognizesA. artemisiifoliawill help improve its bio-control effect. Odorant-binding proteins (OBPs) play a vital role in insect olfactory perception. In this study, the sequence and expression characteristics ofOcomOBP7were analyzed. We obtained the pure protein ofOcomOBP7by prokaryotic expression and purification, and its binding characteristics were analyzed using a fluorescence competitive binding assay. Finally, we verified the function ofOcomOBP7in vivo using RNAi combined with an electroantennography (EAG) assay. The results showed that the binding ability ofOcomOBP7was broad-spectrum and was involved in the host plant localization ofO. communa.AbstractThe olfactory system plays a key role in various insect behaviors, and odorant-binding proteins participate in the first step of the olfactory process.Ophraella communaLesage is an oligophagous phytophagous insect that is a specific biological control agent forAmbrosia artemisiifoliaL. The leaf beetle must identify and locateA. artemisiifoliathrough olfaction; however, its odorant-binding protein (OBP) function has not yet been reported. In this study,OcomOBP7was cloned, and its tissue expression profile and binding ability were analyzed using RT-qPCR and fluorescence binding assays, respectively. Sequence analysis demonstrated thatOcomOBP7belongs to the classical OBP family. The RT-qPCR results showed thatOcomOBP7was specifically expressed in the antennae, indicating thatOcomOBP7may be involved in chemical communication. The fluorescence binding assay showed thatOcomOBP7has an extensive binding ability to alkenes. The electroantennography experiments showed thatO. communaantennal response to α-pinene and ocimene decreased significantly after interference because the two odors specifically bound toOcomOBP7. In summary, α-pinene and oc