ZmGRXCC13, a key factor in coping with drought and saline-alkali stress

Maize (Zea mays L.) is a paramount global staple crop; however, its production is severely limited by diverse abiotic stresses, particularly drought and saline-alkali stress. Although glutaredoxins (GRXs) are known to regulate plant growth and stress responses, their specific functions and underlying molecular mechanisms in maize under drought and saline-alkali conditions remain largely elusive. In this study, we cloned the maize GRX family member ZmGRXCC13 (Zm00001d037757) and characterized its biological functions in abiotic stress tolerance. Quantitative real-time PCR (qRT-PCR) analyses revealed that ZmGRXCC13 is predominantly expressed in maize leaves, and its expression is significantly up-regulated by drought, saline-alkali, and abscisic acid (ABA) treatments. Heterologous expression of ZmGRXCC13 in Escherichia coli (BL21) and yeast cells enhanced their cellular viability under drought and saline-alkali stresses. Subcellular localization assays indicated that the ZmGRXCC13 protein is localized to both the nucleus and the cytoplasm. Furthermore, transgenic Arabidopsis plants overexpressing ZmGRXCC13 exhibited significantly enhanced tolerance to drought and saline-alkali stresses compared with wild-type plants. This robust tolerance was attributed to elevated antioxidant enzyme activities and an enhanced capacity for scavenging reactive oxygen species (ROS), which effectively mitigated stress-induced cellular damage. In addition, yeast two-hybrid (Y2H) and luciferase complementation assay (LCA) confirmed that ZmGRXCC13 physically interacts with Zmrnrl2. Taken together, our results demonstrate that ZmGRXCC13 acts as a positive regulator in plant responses to drought and saline-alkali stresses. These findings provide a solid theoretical foundation for further unraveling the molecular mechanisms underlying abiotic stress tolerance in maize.