NlOrai1 regulates wing dimorphism via the Akt-FoxO signaling pathway in the brown planthopper, Nilaparvata lugens.

BACKGROUND: The brown planthopper (BPH), Nilaparvata lugens, exhibits wing dimorphism, a phenotypic plasticity crucial for its dispersal and population dynamics. While the insulin/insulin-like growth factor signaling (IIS)-FoxO pathway regulates organ growth, its upstream modulators in BPH wing dimorphism remain poorly defined. RESULTS: Among the four calcium signaling genes (NlITPR, NlRyr, NlStim1, and NlOrai1), NlOrai1 exhibited the highest expression under both high- and low-density conditions, and was significantly up-regulated under high-density compared with low-density conditions. Compared with low-density conditions, NlOrai1 expression was significantly elevated during the third to fifth instars under high-density conditions, with particularly high levels in the head and wingbud tissues. RNA interference-mediated knockdown of NlOrai1 reduced expression by 75% and induced severely reduced wings compared to dsGFP controls, elicited molecular changes characterized by down-regulation of NlInR1, and NlVg alongside up-regulation of NlFoxO. Co-knockdown of NlOrai1 and NlFoxO effectively rescued the wing reduction phenotype, knockdown of NlOrai1 and NlInR2 did not compared with NlOrai1 and GFP control groups. Western bolt analysis demonstrated that NlOrai1 knockdown suppressed NlFoxO phosphorylation. CONCLUSION: NlOrai1 acts as a key upstream regulator linking population density cues to the Akt-FoxO signaling axis, controlling wing morph determination in BPH. This functional interaction provides a mechanistic framework for understanding density-dependent polyphenism and offers potential molecular targets for disrupting pest dispersal capabilities. © 2026 Society of Chemical Industry.