Overexpression of Potato PYL16 Gene in Tobacco Enhances the Transgenic Plant Tolerance to Drought Stress

Abstract

PYR/PYL/RCAR proteins are abscisic acid (ABA) receptors that play a crucial role in plant responses to abiotic stresses. However, there have been no research reports on potato PYL so far. In this study, a potato <i>PYL</i> gene named <i>StPYL16</i> was identified based on transcriptome data under drought stress. Molecular characteristics analysis revealed that the StPYL16 protein possesses an extremely conserved PYL family domain. The tissue expression results indicated that the <i>StPYL16</i> is predominantly expressed at high levels in the underground parts, particularly in tubers. Abiotic stress response showed that <i>StPYL16</i> has a significant response to drought treatment. Further research on the promoter showed that drought stress could enhance the activation activity of the <i>StPYL16</i> promoter on the reporter gene. Then, transient and stable expression of <i>StPYL16</i> in tobacco enhanced the drought resistance of transgenic plants, resulting in improved plant height, stem thickness, and root development. In addition, compared with wild-type plants, <i>StPYL16</i> transgenic tobacco exhibited lower malondialdehyde (MDA) content, higher proline accumulation, and stronger superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities. Meanwhile, <i>StPYL16</i> also up-regulated the expression levels of stress-related genes (<i>NtSOD</i>, <i>NtCAT</i>, <i>NtPOD</i>, <i>NtRD29A</i>, <i>NtLEA5</i>, and <i>NtP5CS</i>) in transgenic plants under drought treatment. These findings indicated that the <i>StPYL16</i> gene plays a positive regulatory role in potato responses to drought stress.