Wang Xiaoli, Li Xiaoya, Zheng Saihang, Wang Fusheng, Zhu Shiping, Zhao Xiaochun
Citrus Research Institute, Southwest University/Chinese Academy of Agricultural Sciences, Beibei, Chongqing 400712, China.
National Citrus Engineering Research Center, Beibei, Chongqing 400712, China.
Plants (Basel). 2025 May 22;14(11):1579. doi: 10.3390/plants14111579.
Small auxin-up-regulated RNA () genes are involved in the regulation of dynamic and adaptive growth in higher plants. However, their function and mode of action in citrus root growth are still unknown. Here, we demonstrate that in , acted downstream of the auxin response factor PtrARF8 to regulate root growth by interacting with PtrPP2C.Ds, subfamily type 2C protein phosphatases which interacted with H-ATPase and PtrHA. In this study, several members of family in are identified to be associated with the growth and development of the roots. Among them, was found to be highly expressed in the RT (root tip), and the level of its expression was significantly positively corelated to the length of primary roots ( < 0.01). The overexpression of in citrus significantly promoted the growth of primary roots. In transgenic citrus plants, the expressions of several auxin biosynthesis and transport genes were altered in accordance with the expression of . Y1H and dual-luciferase reporter assays proved that the expression of is regulated by PtrARF8. Y2H and BiFC assay results indicated that PtrSAUR32 interacted with PtrPP2C.Ds subfamily members PtrPP2C.D1, PtrPP2C.D6, and PtrPP2C.D7, of which PtrPP2C.D7 could interact with PtrHA in vivo.
小生长素上调RNA（）基因参与高等植物的动态和适应性生长调控。然而，它们在柑橘根系生长中的功能和作用模式仍不清楚。在这里，我们证明在中，通过与PtrPP2C.Ds相互作用，在生长素响应因子PtrARF8下游发挥作用来调节根系生长，PtrPP2C.Ds是与H-ATPase和PtrHA相互作用的2C亚家族蛋白磷酸酶。在本研究中，柑橘中家族的几个成员被鉴定与根系的生长发育相关。其中，被发现在根尖（RT）中高表达，其表达水平与主根长度显著正相关（<0.01）。在柑橘中过表达显著促进了主根的生长。在转基因柑橘植株中，几个生长素生物合成和运输基因的表达根据的表达而改变。酵母单杂交（Y1H）和双荧光素酶报告基因检测证明的表达受PtrARF8调控。酵母双杂交（Y2H）和双分子荧光互补（BiFC）检测结果表明PtrSAUR32与PtrPP2C.Ds亚家族成员PtrPP2C.D1、PtrPP2C.D6和PtrPP2C.D7相互作用，其中PtrPP2C.D7可在体内与PtrHA相互作用。
