The drought-responsive wheat AP2/ERF transcription factor TaRAP2-13L and its interacting protein TaWRKY10 enhance drought tolerance in transgenic Arabidopsis and wheat (Triticum aestivum L.)

AP2/ERF transcription factors (TFs) are one of the largest TF families involved in plant growth, development, and stress responses. Drought, a major abiotic stress, severely impacts wheat yield and quality. In this study, we identified a wheat AP2/ERF gene, TaRAP2-13L, which was significantly upregulated in response to drought stress. Subcellular localization and transcriptional activity assays indicated that TaRAP2-13L localizes in the nucleus but lacks transcriptional activity. Overexpression of TaRAP2-13L in Arabidopsis enhanced drought tolerance, while silencing TaRAP2-13L in wheat reduced drought tolerance by modulating the ABA signaling pathway and reactive oxygen species homeostasis. Through yeast two-hybrid screening, TaWRKY10 was identified as an interacting protein of TaRAP2-13L, and their interaction was further confirmed by bimolecular fluorescence complementation, luciferase complementation imaging assays, and GST pull-down assays. Functional analysis revealed that TaWRKY10 exhibited a similar role to TaRAP2-13L in drought response. Transcriptional regulation analysis showed that co-expression of TaRAP2-13L and TaWRKY10 complex significantly enhanced transcriptional activity, particularly under drought conditions induced by PEG6000. Moreover, dualluciferase assays demonstrated that TaRAP2-13L and TaWRKY10 can activate the expression of TaSOD3-2A, TaSOD3-2D, TaGPX1-D, and TaNCED2-5B, with co-expression of both TFs enhancing this activation. Further assays revealed that TaRAP2-13L binds to the DRE motif, TaSOD3-2A, and TaSOD3-2D promoters, while TaWRKY10 binds to the W-box, and TaSOD3-2A promoter. These findings highlight a synergistic mechanism by which TaRAP2-13L and TaWRKY10 regulate drought tolerance, offering potential targets for improving drought tolerance in wheat through transgenic strategies.