TaDTGIP1-TaDTG6-B-TaPIF1 module regulates drought stress response in wheat.

Drought is a major environmental constraint to wheat production, yet the genetic and molecular mechanisms underlying drought tolerance remain poorly understood. A gain-of-function protein variant TaDTG6-B has been identified and positively regulates TaPIF1 transcription to enhance wheat drought tolerance. However, the precise molecular pathways driving this response are yet to be fully characterized. In this study, we demonstrate that TaPIF1 plays a crucial role in mediating wheat drought tolerance by regulating stomatal aperture to control transpiration. RNA sequencing combined with biochemical assays revealed that TaPIF1 directly binds to E-box elements to activate the expression of key stress-responsive genes, including TaABI5, TaRD17, and TaP5CS1. Notably, overexpression of TaABI5 enhances wheat drought tolerance by promoting stomatal closure, thereby reducing water loss. Furthermore, TaPIF1 interacts with TaABI5 and the bHLH transcription factor TaAKS1 to synergistically enhancing the transcriptional activation of TaABI5, TaRD17, and TaP5CS1. Additionally, our findings verified that TaDTGIP1 interacts with TaDTG6-B to attenuate its binding affinity and regulatory activity on the TaPIF1 promoter, thereby negatively regulating drought tolerance. Together, our findings unveil the molecular mechanisms underlying wheat drought stress response mediated by the TaDTGIP1-TaDTG6-B-TaPIF1/TaABI5/TaAKS1-target regulatory module and identify potential candidate genes for breeding elite drought-tolerant wheat varieties.