The 14-3-3 protein TaGF14b coordinates TaABF2-dependent ABA signaling and TaSPS2-mediated sugar homeostasis to...

Drought is a major abiotic stress that severely constrains plant growth, development, and crop productivity. Identifying key drought-tolerance genes and deciphering their regulatory mechanisms are critical for enhancing crop resilience. The 14-3-3 proteins, a family of phosphopeptide-binding proteins, play pivotal roles in diverse signaling pathways, thereby influencing metabolism, development, and stress responses. However, their detailed mechanism in mediating drought tolerance in wheat (Triticum aestivum L.) remains largely elusive. In this study, we demonstrate that TaGF14b, a 14-3-3 family member in wheat, functions as a positive regulator of drought stress tolerance. Mechanistically, TaGF14b enhances abscisic acid (ABA) responses by interacting with the ABA-responsive element binding factor TaABF2, thereby amplifying the transactivation activity of downstream drought-responsive genes. Metabolomic profiling revealed that overexpression of TaGF14b mitigates drought-induced metabolic perturbations in wheat. Furthermore, we identified a novel regulatory mechanism wherein TaGF14b interacts with sucrose phosphate synthase TaSPS2, modulating its enzymatic activity to alleviate the perturbations in sugar metabolism under stress conditions. Intriguingly, TaSPS2 weakens the TaGF14b-TaABF2 interaction, thereby fine-tuning the transcriptional activation of ABA-responsive genes and preventing overactivation of the ABA signaling pathway. Our findings uncover a dual role of TaGF14b in coordinating drought tolerance through ABA-dependent gene regulation and the maintenance of sugar metabolism, providing novel insights into strategies for improving drought tolerance in wheat. Through integrated multi-omics and biochemical analyses, we demonstrate the significance of TaGF14b in maintaining metabolic homeostasis and mediating drought stress response, thereby highlighting its potential as a novel target for improving drought tolerance in wheat.