StWRKY46 promotes stomatal closure and enhances potato drought tolerance by mediating the PYL1-ABI2-OST1/SnRK2.5/SnRK2.6 pathway

Drought stress affects crop yield and quality. Abscisic acid (ABA) plays a crucial role in plant responses to drought stress; however, the signal transduction mechanism in potato (Solanum tuberosum L.) remains unclear. This study identifies a WRKY transcription factor (TF) member, StWRKY46, that enhances drought tolerance in potato. Under drought, StWRKY46 binds directly to the promoter of StPYL1 (a PYR/PYL family ABA receptor) and activates its transcription, triggering the ABA signaling pathway and improving drought tolerance in potato. StPYL1 interacts with StHAB1, StPP2C24, StPP2C51.1, and StABI2. StABI2 acts as a key negative regulator of ABA signaling. It interacts with StOST1, StSnRK2.5, and StSnRK2.6 to regulate the expression of stomatal movement-related genes, including the slow-type anion channel 1 (StSLAC1) and guard cell hydrogen peroxide-resistant 1 (StGHR1), thereby potentiating ABA-induced stomatal closure. Overall, our findings demonstrate the molecular mechanism of StWRKY46-mediated drought tolerance through the ABA-StPYL1-StABI2-StOST1/StSnRK2.5/StSnRK2.6 pathway in potato.