Modulation of GSNOR activity for improved NO homeostasis and flood resilience in plants

Flood-induced hypoxia (low oxygen concentration) is increasing in frequency and intensity due to climate change, leading to significant crop yield losses and posing a major threat to global food security. <i>S</i>-nitrosoglutathione reductase (GSNOR) is a highly conserved, cysteine-rich homodimer that regulates the cellular level of the most abundant nitric oxide (NO) reservoir <i>S</i>-nitrosoglutathione (GSNO). GSNOR plays a fundamental role in NO homeostasis, as well as in plant development and stress responses, particularly hypoxia. This review summarizes the critical position of GSNOR in the plant hypoxia regulation network. We discuss how GSNOR controls the intracellular pool of <i>S</i>-nitrosothiols (SNOs), especially GSNO, thereby mitigating cytotoxic nitrosative stress while fine-tuning NO-mediated posttranslational modifications (PTMs), such as <i>S</i>-nitrosylation. Furthermore, we explored the regulation of GSNOR activity through various mechanisms, including oxidative PTMs and protein‒protein interactions. Targeted manipulation of GSNOR activity represents a promising strategy for enhancing flood tolerance in agriculturally important crops. We propose possible approaches for GSNOR manipulation and highlight urgent questions that must be addressed in future research to improve flood resilience in agricultural systems and protect global food security.