Overexpression of AmCML24 Improves Abiotic Stress Tolerance and Upregulates Stress-Responsive Genes in Arabidopsis

With the intensification of global climate change, environmental issues such as soil salinization and drought have exerted an increasingly prominent impact on plants. Tibetan peach (<i>Amygdalus mira</i>), a rare native tree species of the genus Amygdalus in the Rosaceae family, possesses extremely strong tolerance to cold, drought, and disease stress. In the previous study, we found that the protein abundance of a calcium-binding protein, AmCML24, was significantly upregulated in Tibetan peach under drought stress, leading us to hypothesize that it plays an important role in the molecular mechanisms underlying plant responses to abiotic stresses. Therefore, this study focuses on AmCML24, aiming to preliminarily characterize the stress-tolerant function of AmCML24 and explore its biological role in plant tolerance to saline-alkali and drought stresses. Results demonstrated that <i>AmCML24</i> responds to multiple abiotic stresses. Yeast and <i>Arabidopsis thaliana</i> lines overexpressing <i>AmCML24</i> exhibited enhanced tolerance to NaCl, NaHCO₃, and mannitol stresses, with a significant upregulation in the expression of stress-responsive genes. This study lays a solid foundation for deciphering the stress regulatory network of Tibetan peach and elucidating the biological function of <i>AmCML24</i>, while also providing a scientific basis for the genetic improvement, exploitation, and utilization of Tibetan peach germplasm resources.