Antioxidant Defense Systems in Plants: Mechanisms, Regulation, and Biotechnological Strategies for Enhanced Oxidative Stress Tolerance.

Plants must contend with oxidative stress, a paradoxical phenomenon in which reactive oxygen species (ROS) can cause cellular damage while also serving as key signaling molecules. Environmental stressors, such as drought, salinity, and temperature extremes, promote ROS accumulation, affecting plant growth and productivity. To maintain redox homeostasis, plants rely on antioxidant systems comprising enzymatic defenses, such as superoxide dismutase, catalase, and ascorbate peroxidase, and non-enzymatic molecules, including ascorbate, glutathione, flavonoids, and emerging compounds such as proline and nano-silicon. This review provides an integrated overview of antioxidant responses and their modulation through recent biotechnological advances, emphasizing the role of emerging technologies in advancing our understanding of redox regulation and translating molecular insights into stress-resilient phenotypes. Omics approaches have enabled the identification of redox-related genes, while genome editing tools, particularly those based on clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) proteins, offer opportunities for precise functional manipulation. Artificial intelligence and systems biology are accelerating the discovery of regulatory modules and enabling predictive modeling of antioxidant networks. We also highlight the contribution of synthetic biology to the development of stress-responsive gene circuits and address current regulatory and ethical considerations. Overall, this review aims to provide a comprehensive perspective on molecular, biochemical, and technological strategies to enhance oxidative stress tolerance in plants, thereby contributing to sustainable agriculture and food security in a changing climate.