Genetic Manipulation of Reactive Oxygen Species (ROS) Homeostasis Utilizing CRISPR/Cas9-Based Gene Editing in Rice.

Reactive oxygen species (ROS) are now recognized as key signals in plant stress responses. Adverse environmental conditions can either promote ROS production or downregulate antioxidative enzymes, leading to the alteration of redox homeostasis and activation of ROS-linked stress signaling. To uncover their signaling mechanisms and to characterize related components, genetic modification of ROS homeostasis is a central approach.

Analyzing the Function of Catalase and the Ascorbate-Glutathione Pathway in HO Processing: Insights from an Experimentally Constrained Kinetic Model.

Significance: Plant stress involves redox signaling linked to reactive oxygen species such as hydrogen peroxide (HO), which can be generated at high rates in photosynthetic cells. The systems that process HO include catalase (CAT) and the ascorbate-glutathione pathway, but interactions between them remain unclear. Modeling can aid interpretation and pinpoint areas for investigation.

Glutathione oxidation in response to intracellular HO: Key but overlapping roles for dehydroascorbate reductases.

Glutathione is a pivotal molecule in oxidative stress, during which it is potentially oxidized by several pathways linked to HO detoxification. We have investigated the response and functional importance of 3 potential routes for glutathione oxidation pathways mediated by glutathione S-transferases (GST), glutaredoxin-dependent peroxiredoxins (PRXII), and dehydroascorbate reductases (DHAR) in Arabidopsis during oxidative stress. Loss-of-function gstU8, gstU24, gstF8, prxIIE and prxIIF mutants as well as double gstU8 gstU24, gstU8 gstF8, gstU24 gstF8, prxIIE prxIIF mutants were obtained.

Cytosolic and Chloroplastic DHARs Cooperate in Oxidative Stress-Driven Activation of the Salicylic Acid Pathway.

The complexity of plant antioxidative systems gives rise to many unresolved questions. One relates to the functional importance of dehydroascorbate reductases (DHARs) in interactions between ascorbate and glutathione. To investigate this issue, we produced a complete set of loss-of-function mutants for the three annotated Arabidopsis () DHARs.

Missing links in understanding redox signaling via thiol/disulfide modulation: how is glutathione oxidized in plants?

Glutathione is a small redox-active molecule existing in two main stable forms: the thiol (GSH) and the disulphide (GSSG). In plants growing in optimal conditions, the GSH:GSSG ratio is high in most cell compartments. Challenging environmental conditions are known to alter this ratio, notably by inducing the accumulation of GSSG, an effect that may be influential in the perception or transduction of stress signals.