Optix Regulated the Expression of NlObps to Participate in the Recognition of a Volatile Strongly Emitted from Rice Plants

Linalool serves as a key chemical signaling molecule that regulates the behavior of Nilaparvata lugens. Our previous research revealed that multiple odorant binding proteins (OBPs) participate in the response of N. lugens to linalool induction. However, the precise mechanisms governing their olfactory functions during linalool adaptation, as well as their coordinated regulation in response to linalool stimulation, remain poorly understood. Here, we employed linalool-induced transcriptomics to uncover transcription factor optix as a pivotal regulator governing NlObps expression in N. lugens. Through RNA interference (RNAi), H-type olfactometer behavioral assays, dual-luciferase reporter assays, cellular overexpression experiments, yeast one-hybrid screening (Y1H), and electrophoretic mobility shift assays (EMSA), our results demonstrated that optix directly regulates the expression of NlObp6, NlObp9, and NlObp10, thereby mediating BPH's olfactory adaptation to rice defensive compounds. Our findings elucidate mechanistic insights into N. lugens' adaptation to plant defense volatiles and reveal novel targets for semiochemical-based pest management through olfactory manipulation.