Jing Pei, Zou Juanzi, Kong Lin, Hu Shiqi, Wang Biying, Yang Jun, Xie Guosheng
MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China.
MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China.
Plant Sci. 2016 Jun;247:104-14. doi: 10.1016/j.plantsci.2016.03.011. Epub 2016 Mar 24.
Calcium-binding proteins play key roles in the signal transduction in the growth and stress response in eukaryotes. However, a subfamily of proteins with one EF-hand motif has not been fully studied in higher plants. Here, a novel small calcium-binding protein with a C-terminal centrin-like domain (CCD1) in rice, OsCCD1, was characterized to show high similarity with a TaCCD1 in wheat. As a result, OsCCD1 can bind Ca(2+) in the in vitro EMSA and the fluorescence staining calcium-binding assays. Transient expression of green fluorescent protein (GFP)-tagged OsCCD1 in rice protoplasts showed that OsCCD1 was localized in the nucleus and cytosol of rice cells. OsCCD1 transcript levels were transiently induced by osmotic stress and salt stress through the calcium-mediated ABA signal. The rice seedlings of T-DNA mutant lines showed significantly less tolerance to osmotic and salt stresses than wild type plants (p<0.01). Conversely, its overexpressors can significantly enhance the tolerance to osmotic and salt stresses than wild type plants (p<0.05). Semi-quantitative RT-PCR analysis revealed that, OsDREB2B, OsAPX1 and OsP5CS genes are involved in the rice tolerance to osmotic and salt stresses. In sum, OsCCD1 gene probably affects the DREB2B and its downstream genes to positively regulate osmotic and salt tolerance in rice seedlings.
钙结合蛋白在真核生物的生长和应激反应信号转导中发挥关键作用。然而，具有一个EF-手基序的蛋白质亚家族在高等植物中尚未得到充分研究。在此，对水稻中一种具有C末端中心蛋白样结构域（CCD1）的新型小钙结合蛋白OsCCD1进行了表征，发现其与小麦中的TaCCD1具有高度相似性。结果表明，在体外电泳迁移率变动分析（EMSA）和荧光染色钙结合试验中，OsCCD1能够结合Ca(2+)。在水稻原生质体中瞬时表达绿色荧光蛋白（GFP）标记的OsCCD1表明，OsCCD1定位于水稻细胞的细胞核和细胞质中。通过钙介导的脱落酸（ABA）信号，渗透胁迫和盐胁迫可瞬时诱导OsCCD1转录水平。T-DNA突变系的水稻幼苗对渗透胁迫和盐胁迫的耐受性明显低于野生型植株（p<0.01）。相反，其过表达植株对渗透胁迫和盐胁迫的耐受性明显高于野生型植株（p<0.05）。半定量逆转录聚合酶链反应（RT-PCR）分析表明，OsDREB2B、OsAPX1和OsP5CS基因参与了水稻对渗透胁迫和盐胁迫的耐受性。总之，OsCCD1基因可能通过影响DREB2B及其下游基因来正向调节水稻幼苗的渗透胁迫和盐胁迫耐受性。
