Redox-regulated transcription in plants: Emerging concepts

In plants, different stimuli, both internal and external, activate production of reactive oxygen species (ROS). Photosynthesis is considered as high rate redox-metabolic process with rapid transients including light/photon capture, electron fluxes, and redox potentials that can generate ROS; thus, regulatory systems are required to minimize ROS production. Despite their potential for causing harmful oxidations, it is now accepted that redox homeostasis mechanisms that maintain the intracellular reducing environment make it possible to use ROS as powerful signaling molecules within and between cells. Redox and ROS information from the chloroplasts is a fine-tuning mechanism both inside the chloroplast and as retrograde signal to the cytosol and nucleus to control processes such as gene expression/transcription and translation. Wide repertoires of downstream target genes expression (activation/repression) is regulated by transcription factors. In many cases, transcription factors function through various mechanisms that affect their subcellular localization and or activity. Some post-translational modifications (PTMs) known to regulate the functional state of transcription factors are phosphorylation, acetylation, and SUMOylation, ubiquitylation and disulfide formation. Recently, oxPTMs, targeted in redox proteomics, can provide the bases to study redox regulation of low abundant nuclear proteins. This review summarizes the recent advances on how cellular redox status can regulate transcription factor activity, the implications of this regulation for plant growth and development, and by which plants respond to environmental/abiotic stresses.