Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, P.O Box 65 (Viikinkaari 1), FI-00014, Helsinki, Finland.
Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, P.O Box 65 (Viikinkaari 1), FI-00014, Helsinki, Finland; Institute of Technology, University of Tartu, Nooruse 1, Tartu, 50411, Estonia.
Free Radic Biol Med. 2019 Apr;134:555-566. doi: 10.1016/j.freeradbiomed.2019.02.006. Epub 2019 Feb 6.
Reactive oxygen species (ROS) are key signalling intermediates in plant metabolism, defence, and stress adaptation. In plants, both the chloroplast and mitochondria are centres of metabolic control and ROS production, which coordinate stress responses in other cell compartments. The herbicide and experimental tool, methyl viologen (MV) induces ROS generation in the chloroplast under illumination, but is also toxic in non-photosynthetic organisms. We used MV to probe plant ROS signalling in compartments other than the chloroplast. Taking a genetic approach in the model plant Arabidopsis (Arabidopsis thaliana), we used natural variation, QTL mapping, and mutant studies with MV in the light, but also under dark conditions, when the chloroplast electron transport is inactive. These studies revealed a light-independent MV-induced ROS-signalling pathway, suggesting mitochondrial involvement. Mitochondrial Mn SUPEROXIDE DISMUTASE was required for ROS-tolerance and the effect of MV was enhanced by exogenous sugar, providing further evidence for the role of mitochondria. Mutant and hormone feeding assays revealed roles for stress hormones in organellar ROS-responses. The radical-induced cell death1 mutant, which is tolerant to MV-induced ROS and exhibits altered mitochondrial signalling, was used to probe interactions between organelles. Our studies suggest that mitochondria are involved in the response to ROS induced by MV in plants.
活性氧（ROS）是植物代谢、防御和应激适应的关键信号中间体。在植物中，叶绿体和线粒体都是代谢控制和 ROS 产生的中心，它们协调其他细胞区室的应激反应。除草剂和实验工具甲紫（MV）在光照下诱导叶绿体中 ROS 的产生，但在非光合生物中也是有毒的。我们使用 MV 来探测除叶绿体以外的植物 ROS 信号转导。我们以模式植物拟南芥（Arabidopsis thaliana）为研究对象，采用遗传方法，利用 MV 在光照下以及在黑暗条件下（当叶绿体电子传递失活时）进行自然变异、QTL 作图和突变体研究。这些研究揭示了一种不依赖于光的 MV 诱导的 ROS 信号通路，表明线粒体的参与。线粒体 Mn SUPEROXIDE DISMUTASE 对于 ROS 耐受性是必需的，MV 的作用在外源糖的作用下增强，这为线粒体的作用提供了进一步的证据。突变体和激素喂养实验揭示了应激激素在细胞器 ROS 反应中的作用。自由基诱导的细胞死亡 1 突变体对 MV 诱导的 ROS 具有耐受性，并表现出改变的线粒体信号，被用来探测细胞器之间的相互作用。我们的研究表明，线粒体参与了植物中 MV 诱导的 ROS 反应。
