The Nuclear Redox Code: Orchestrating Growth, Development, and Stress Resilience.

Reactive oxygen, nitrogen, and sulfur species (RONSs) are essential signaling molecules in plants, with their production highly compartmentalized within the cell. In this review, we advance the concept of the "nuclear redox code," a framework in which the plant cell nucleus functions as a signaling hub that actively curates its own redox environment and translates oxidative signals into cellular decisions. We summarize current knowledge on the maintenance of nuclear redox homeostasis, the oxidative modification of nuclear proteins and chromatin, and how these modifications influence gene expression, cell cycle progression, and cell fate determination. We propose that the nucleus integrates these molecular events through a hierarchical architecture, coupling transient oxidative post-translational modifications with stable chromatin marks to coordinate growth, development, and stress adaptation. We also highlight key unresolved questions and discuss how a systems-level understanding of the nuclear redox code may guide the development of stress-resilient crops.