Functional Characterization of an Odorant Receptor in the Brown Planthopper, <i>Nilaparvata lugens</i> , Tuned to 2-Dodecanone

Insect olfactory systems detect environmental volatiles to guide key behaviors. The specific binding of odorants to olfactory neurons mediated by odorant receptors (ORs) constitutes the fundamental basis of olfaction. The brown planthopper (BPH, <i>Nilaparvata lugens</i>) is a major global rice pest; however, there have been few studies on the function of BPH NlugORs. Here, we conducted transcriptome sequencing of adult and nymph antennae with differential expression analysis and quantitative real-time PCR (qPCR) validation to screen candidate OR genes. We functionally characterized three NlugORs (NlugOR5, NlugOR36, and NlugOR39) using heterologous expression in <i>Xenopus</i> oocytes and two-electrode voltage clamp (TEVC) recordings and found NlugOR36 specifically responsive to 2-dodecanone. Both electroantennography and behavioral assays confirmed the bioactivity of 2-dodecanone in BPHs, showing electrophysiological responses in both sexes and consistent repellent effects. Critically, the RNA interference (RNAi)-mediated silencing of <i>NlugOR36</i> abolished this repellent behavior. Collectively, NlugOR36 serves as a key receptor for 2-dodecanone detection in BPH, offering new insights for sustainable control strategies against this pest.