Cold‐Induced Downregulation of TaSAP7‐A2 Activates the TaCOLD1‐2D–TaCML5‐7B Module to Enhance Cold Tolerance in Wheat

ABSTRACT Cold stress, including chilling and freezing, severely limits global wheat ( Triticum aestivum L.) production. Although many cold‐responsive genes have been identified, the mechanisms that connect early cold sensing to transcriptional regulation and downstream physiological adaptation are still not fully understood. By generating TaCOLD1‐2D overexpression and CRISPR/Cas9 knockout lines in wheat and integrating protein interaction assays, transcriptional regulation analyses, physiological measurements, and haplotype analysis of 143 Chinese wheat accessions, we characterized the TaSAP7‐A2/TaCOLD1‐2D/TaCML5‐7B regulatory module. TaSAP7‐A2 functions as a transcriptional repressor that directly binds the TaCOLD1‐2D promoter under normal conditions. Cold exposure rapidly downregulates TaSAP7‐A2 , relieving this repression and elevating TaCOLD1‐2D expression. The increased TaCOLD1‐2D then recruits TaCML5‐7B in a Ca 2+ ‐dependent manner. This cascade activates ABA biosynthesis and signalling, promotes rapid stomatal closure, maintains ROS homoeostasis, and fine‐tunes CBF–COR gene expression, conferring robust tolerance at both seedling and booting stages without affecting growth under non‐stress conditions. A natural TaSAP7‐A2 promoter haplotype (Hap‐7A‐2) with weakened repressive activity shows strong artificial selection in high‐latitude cultivars. These results uncover an efficient derepression strategy that integrates early cold perception with Ca 2+ –ABA‐mediated protective responses. The module provides valuable genetic targets for developing climate‐resilient wheat while avoiding the growth penalties associated with constitutive defence activation.