Iron transporter1 OsIRT1 positively regulates saline–alkaline stress tolerance in Oryza sativa

Soil salinization–alkalization severely affects plant growth and crop yield worldwide, especially in the Songnen Plain of Northeast China. Saline–alkaline stress increases the pH around the plant roots, thereby limiting the absorption and transportation of nutrients and ions, such as iron (Fe). Fe is an essential micronutrient that plays important roles in many metabolic processes during plant growth and development, and it is acquired by the root cells via iron-regulated transporter1 (IRT1). However, the function of Oryza sativa IRT1 (OsIRT1) under soda saline–alkaline stress remains unknown. Therefore, in this study, we generated OsIRT1 mutant lines and OsIRT1-overexpressing lines in the background of the O. sativa Songjing2 cultivar to investigate the roles of OsIRT1 under soda saline–alkaline stress. The OsIRT1-overexpressing lines exhibited higher tolerance to saline–alkaline stress compared to the mutant lines during germination and seedling stages. Moreover, the expression of some saline–alkaline stress-related genes and Fe uptake and transport-related genes were altered. Furthermore, Fe and Zn contents were upregulated in the OsIRT1-overexpressing lines under saline–alkaline stress. Further analysis revealed that Fe and Zn supplementation increased the tolerance of O. sativa seedlings to saline–alkaline stress. Altogether, our results indicate that OsIRT1 plays a significant role in O. sativa by repairing the saline–alkaline stress-induced damage. Our findings provide novel insights into the role of OsIRT1 in O. sativa under soda saline–alkaline stress and suggest that OsIRT1 can serve as a potential target gene for the development of saline–alkaline stress-tolerant O. sativa plants.