ROS- and nitric oxide-dependent regulation of ion and metal homeostasis in plants.

Deterioration and impoverishment of soil, caused by environmental pollution and climate change result in reduced crop productivity. To adapt to hostile soils, plants have developed a complex network of factors involved in stress sensing, signal transduction and adaptive responses. The chemical properties of reactive oxygen and nitrogen species (ROS, RNS) allow them to participate in integrating the perception of external signals by fine-tuning protein redox regulation and signal transduction, triggering specific gene expression. In this review, we update and summarise the progress in understanding the mechanistic basis of ROS and RNS production at subcellular level in plants and their role in the regulation of ion channels/transporters, at both transcriptional level and post-translational level. We have also carried out an in silico analyses of different redox-dependent modifications of ion channels/transporters and identified Cys and Tyr targets of NO of metal transporters. Further we summarized possible ROS- and RNS-dependent sensors involved in metal stress sensing, such as kinases and phosphatases, as well as some transcription factors regulated by ROS and RNS that could be involved in metal homeostasis. Understanding the ROS and RNS-dependent signalling events is crucial to design new strategies to fortified crops, improve plant tolerance against nutritional imbalance and metal toxicity.