The Effect of Auxin and Nitric Oxide on Root Hair Formation in Rice

Root hair development performs the essential tasks of providing water, nutrients, and physical support to plants. Therefore, understanding the regulation of root hair development is of agronomic importance. In this study, we examined the effect of auxin and nitric oxide (NO) on root hair formation in rice. Treatment with sodium nitroprusside (SNP, a NO donor) or indole-3-butyric acid (IBA, a naturally occurring auxin) induced root hair formation and elongation. Root hair formation induced by SNP and IBA was reduced by the specific NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline- 1-oxyl-3-oxide (cPTIO). Endogenous NO was detected by the specific fluorescence probe 4-amino-5-methylamino-2'7'Auxin, Nitric oxide, Rice, Root hairs- difluorofluorescein diacetate. Sodium nitroprusside and IBA were effective in inducing NO fluorescence, which was blocked by cPTIO. Results also showed that IBA-induced NO generation is primarily due to nitrate reductase (NR) in rice roots. Furthermore, NO generation caused by SNP or IBA was localized in root area corresponding to root hair emergence. Collectively, our data suggest that NO is responsible for auxin-induced root hair formation in rice.