Two transcription factor cascades regulate odorant-binding protein NlOBP8 affecting the recognition of linalool in the brown planthopper Nilaparvata lugens.

The insect olfactory system is pivotal in mediating chemical-driven behaviors, including host plant selection, mate identification, oviposition site localization, and ecological niche recognition. Although odorant-binding proteins (OBPs) are known to facilitate olfactory signal transduction in insects, the transcriptional regulatory mechanisms governing their expression remain elusive. Here, we identified 2 transcriptional cascades involving the transcription factors (TFs) distal-less (Dll) and aristaless (al) that converge to regulate NlObp8 expression in the brown planthopper (Nilaparvata lugens, BPH) through bioinformatics and transcriptomic analysis. The functional impact of the 2 TFs was validated using the dual-luciferase reporter assays and yeast 1-hybrid assays. RNA interference-mediated knockdown of Nlal significantly downregulated NlObp8 expression and abolished the repellent behavioral response of BPHs to linalool. Furthermore, silencing of NlDll resulted in significant downregulation of Nlal expression. These results revealed that the cascade regulatory mechanism, involving direct al binding and indirect Dll-mediated transcriptional activation, provided molecular targets for disrupting olfactory-driven behaviors in agricultural pest management.