Reactive Oxygen Species and Phytohormone Signalling: Redox Modifications Shaping Plant Growth and Stress Acclimation

Reactive oxygen species (ROS) and phytohormones are essential components of a precisely coordinated signalling network that regulates plant growth, development and adaptation to environmental changes. This review synthesises current knowledge to elucidate the specific oxidative modification mechanisms by which ROS target core signalling components, biosynthetic enzymes, as well as transport proteins throughout all hormonal pathways and distils cross-pathway principles that define a coherent redox-guided regulatory architecture. We further delineate the reciprocal regulation where phytohormones modulate ROS homeostasis to coordinate plant growth and stress tolerance, establishing bidirectional circuits that enable dynamic resource allocation and we discuss translational opportunities for precision editing of redox-sensitive nodes in crops. Understanding the interplay between ROS and phytohormones not only enhances our knowledge of plant adaptive strategies but also provides a conceptual framework for developing crops with optimised yield and stress tolerance through molecular breeding and hormone-based agrochemical interventions.