Xu Peipei, Cai Weiming
Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Graduate School of Chinese Academy of Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.
Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Graduate School of Chinese Academy of Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
J Exp Bot. 2014 Jul;65(12):3277-87. doi: 10.1093/jxb/eru178. Epub 2014 Apr 30.
Of the diverse abiotic stresses, low temperature is one of the major limiting factors that lead to a series of morphological, physiological, biochemical, and molecular changes in plants. Ran, an evolutionarily conserved small G-protein family, has been shown to be essential for the nuclear translocation of proteins. It also mediates the regulation of cell cycle progression in mammalian cells. However, little is known about Ran function in rice (Oryza sativa). We report here that Ran gene OsRAN1 is essential for the molecular improvement of rice for cold tolerance. Ran also affects plant morphogenesis in transgenic Arabidopsis thaliana. OsRAN1 is ubiquitously expressed in rice tissues with the highest expression in the spike. The levels of mRNA encoding OsRAN1 were greatly increased by cold and indoleacetic acid treatment rather than by addition of salt and polyethylene glycol. Further, OsRAN1 overexpression in Arabidopsis increased tiller number, and altered root development. OsRAN1 overexpression in rice improves cold tolerance. The levels of cellular free Pro and sugar levels were highly increased in transgenic plants under cold stress. Under cold stress, OsRAN1 maintained cell division and cell cycle progression, and also promoted the formation of an intact nuclear envelope. The results suggest that OsRAN1 protein plays an important role in the regulation of cellular mitosis and the auxin signalling pathway.
在各种非生物胁迫中，低温是导致植物发生一系列形态、生理、生化和分子变化的主要限制因素之一。Ran是一个在进化上保守的小G蛋白家族，已被证明对蛋白质的核转运至关重要。它还介导哺乳动物细胞中细胞周期进程的调控。然而，关于Ran在水稻（Oryza sativa）中的功能却知之甚少。我们在此报告，Ran基因OsRAN1对水稻耐寒性的分子改良至关重要。Ran在转基因拟南芥中也影响植物形态发生。OsRAN1在水稻组织中普遍表达，在穗中表达量最高。编码OsRAN1的mRNA水平在冷处理和吲哚乙酸处理下大幅增加，而在添加盐和聚乙二醇时并未增加。此外，OsRAN1在拟南芥中的过表达增加了分蘖数，并改变了根系发育。OsRAN1在水稻中的过表达提高了耐寒性。在冷胁迫下，转基因植物中细胞游离脯氨酸水平和糖水平大幅增加。在冷胁迫下，OsRAN1维持细胞分裂和细胞周期进程，还促进完整核膜的形成。结果表明，OsRAN1蛋白在细胞有丝分裂调控和生长素信号通路中发挥重要作用。
