State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, China.
PLoS One. 2013 Dec 3;8(12):e81849. doi: 10.1371/journal.pone.0081849. eCollection 2013.
Rice SPX domain gene, OsSPX1, plays an important role in the phosphate (Pi) signaling network. Our previous work showed that constitutive overexpression of OsSPX1 in tobacco and Arabidopsis plants improved cold tolerance while also decreasing total leaf Pi. In the present study, we generated rice antisense and sense transgenic lines of OsSPX1 and found that down-regulation of OsSPX1 caused high sensitivity to cold and oxidative stresses in rice seedlings. Compared to wild-type and OsSPX1-sense transgenic lines, more hydrogen peroxide accumulated in seedling leaves of OsSPX1-antisense transgenic lines for controls, cold and methyl viologen (MV) treatments. Glutathione as a ROS scavenger could protect the antisense transgenic lines from cold and MV stress. Rice whole genome GeneChip analysis showed that some oxidative-stress marker genes (e.g. glutathione S-transferase and P450s) and Pi-signaling pathway related genes (e.g. OsPHO2) were significantly down-regulated by the antisense of OsSPX1. The microarray results were validated by real-time RT-PCR. Our study indicated that OsSPX1 may be involved in cross-talks between oxidative stress, cold stress and phosphate homeostasis in rice seedling leaves.
水稻 SPX 结构域基因 OsSPX1 在磷（Pi）信号网络中发挥着重要作用。我们之前的工作表明，在烟草和拟南芥植物中组成型过表达 OsSPX1 可提高其耐寒性，同时降低总叶 Pi。在本研究中，我们生成了水稻反义及正义 OsSPX1 转基因株系，并发现 OsSPX1 的下调导致水稻幼苗对冷和氧化胁迫高度敏感。与野生型和 OsSPX1-正义转基因株系相比，对照、冷和甲基紫精（MV）处理下，OsSPX1-反义转基因株系的幼苗叶片中积累了更多的过氧化氢。作为 ROS 清除剂的谷胱甘肽可保护反义转基因株系免受冷和 MV 胁迫。水稻全基因组 GeneChip 分析表明，一些氧化应激标记基因（如谷胱甘肽 S-转移酶和 P450s）和 Pi 信号通路相关基因（如 OsPHO2）在 OsSPX1 的反义表达下显著下调。实时 RT-PCR 验证了微阵列结果。我们的研究表明，OsSPX1 可能参与了水稻幼苗叶片中氧化应激、冷应激和磷酸盐稳态之间的交叉对话。
