Institute of Rice Research, Anhui Academy of Agricultural Science, Hefei 230031, China.
Plant Cell Environ. 2013 Apr;36(4):775-88. doi: 10.1111/pce.12013. Epub 2012 Oct 19.
Mitochondrial retrograde regulation (MRR) is the transduction of mitochondrial signals to mediate nuclear gene expression. It is not clear whether MRR is a common regulation mechanism in plant abiotic stress response. In this study, we analysed the early abiotic stress response of the rice OsAOX1 genes, and the induction of OsAOX1a and OsAOX1b (OsAOX1a/b) was selected as a working model for the stress-induced MRR studies. We found that the induction mediated by the superoxide ion (O2·(-) )-generating chemical methyl viologen was stronger than that of hydrogen peroxide (H2 O2 ). The addition of reactive oxygen species (ROS) scavengers demonstrated that the stress induction was reduced by eliminating O2·(-) . Furthermore, the stress induction did not rely on chloroplast- or cytosol-derived O2·(-) . Next, we generated transgenic plants overexpressing the superoxide dismutase (SOD) gene at different subcellular locations. The results suggest that only the mitochondrial SOD, OsMSD, attenuated the stress induction of OsAOX1a/b specifically. Therefore, our findings demonstrate that abiotic stress initiates the MRR on OsAOX1a/b and that mitochondrial O2·(-) is involved in the process.
线粒体逆行调控（MRR）是线粒体信号转导介导核基因表达的过程。目前尚不清楚 MRR 是否是植物非生物胁迫响应的共同调节机制。在本研究中，我们分析了水稻 OsAOX1 基因的早期非生物胁迫响应，选择 OsAOX1a 和 OsAOX1b（OsAOX1a/b）的诱导作为应激诱导 MRR 研究的工作模型。我们发现，超氧阴离子（O2·(-)）生成化学试剂甲基紫精诱导的诱导作用强于过氧化氢（H2O2）。活性氧（ROS）清除剂的添加表明，通过消除 O2·(-)，应激诱导减少。此外，应激诱导不依赖叶绿体或细胞质来源的 O2·(-)。接下来，我们生成了在不同亚细胞位置过表达超氧化物歧化酶（SOD）基因的转基因植物。结果表明，只有线粒体 SOD（OsMSD）特异性减弱了 OsAOX1a/b 的应激诱导。因此，我们的发现表明非生物胁迫引发了 OsAOX1a/b 的 MRR，并且线粒体 O2·(-) 参与了该过程。
