Overexpression of the Potato StPYL20 Gene Enhances Drought Resistance and Root Development in Transgenic Plants

Drought is a primary limiting factor for potato growth. PYR/PYL/RCAR (referred to hereafter as PYL) proteins, as receptors for abscisic acid (ABA), play a crucial role in the plant response to drought stress. However, the underlying mechanisms of this control remain largely elusive in potatoes. In this study, a potato <i>StPYL20</i> gene was identified through genome-wide investigation and transcriptome analysis under drought stress. Molecular feature analysis revealed that the <i>StPYL20</i> gene exhibits the highest expression level in tubers, and is significantly up-regulated under ABA and drought stress conditions. The StPYL20 protein harbors a conserved domain exclusive to the PYL family. Further functional analysis showed that both transient and stable expressions of <i>StPYL20</i> in tobacco enhanced the drought resistance of transgenic plants, resulting in increased plant height, leaf number, and fresh weight, and an improved root system. Compared to wild-type plants under drought conditions, transgenic tobacco with the <i>StPYL20</i> gene exhibited lower levels of malondialdehyde (MDA), higher proline (Pro) accumulation, and increased antioxidant enzyme activity. Moreover, overexpression of the <i>StPYL20</i> gene heightened the sensitivity of transgenic plants to ABA. Furthermore, <i>StPYL20</i> up-regulated the expression of stress response and development-related genes in transgenic plants under drought stress. In conclusion, our findings indicated that <i>StPYL20</i> enhances drought resistance and root development in transgenic plants, and plays a positive regulatory role in the potato's response to drought stress.