The transcription factor TaWRKY58 coordinates growth and drought sensitivity in wheat by repressing TaLRR and TaBCS1

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Balancing growth and stress adaptation is essential for optimizing crop productivity, yet the transcriptional mechanisms underlying this trade-off in wheat remain poorly understood. Here, we identify the WRKY transcription factor TaWRKY58 as a key repressor coordinating plant architecture and drought response. Loss-of-function mutants of TaWRKY58 exhibit increased plant height and early flowering, accompanied by elevated gibberellin levels, while overexpression restores wild-type phenotypes. Under drought stress, TaWRKY58 represses soluble sugar accumulation, and its mutants show enhanced drought tolerance. Using DAP-seq, we identified genome-wide binding sites of TaWRKY58 and uncovered a W-box-like motif enriched in its target promoters. Electrophoretic mobility shift and dual-luciferase assays confirmed that TaWRKY58 directly binds to and represses two key targets: TaLRR, encoding a leucine-rich repeat protein, and TaBCS1, encoding a mitochondrial AAA⁺ ATPase. Mutants of TaLRR and TaBCS1 display dwarfism and drought hypersensitivity, respectively, mirroring aspects of the TaWRKY58 overexpression phenotype. Our data support a model in which TaWRKY58 functions as a transcriptional repressor in a coherent regulatory module that fine-tunes growth and stress adaptation by modulating signaling and energy metabolism. This mechanism offers a potential strategy for breeding wheat with optimized yield stability under fluctuating environments.

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