In wheat, exposure to low temperatures (LT) during the middle and late stages of seed development induces the release of dormancy. However, the underlying regulatory mechanism remains unclear. Here, we identified a novel microRNA (miR1832), which is downregulated by LT and located at a key node of the related regulatory network, using the whole-transcriptome sequencing technology. Germination experiments showed that overexpression of miR1832 enhanced seed dormancy (SD), while its silencing repressed seed dormancy. Further sequence variation and association analysis indicated that an A/G mutation at -670 bp in the miR1832 promoter was significantly associated with phenotypic difference in seed dormancy across wheat varieties, with A associated with strong dormancy. Combining yeast one-hybrid (Y1H), electrophoretic mobility shift assay (EMSA), and dual-luciferase (LUC) reporter assays, we found that the LT-responsive Dof transcription factor TaDof-2D binds directly to the A site in the miR1832 promoter and inhibits its transcription. Subsequently, through expression analysis, dual-LUC assay, and 5'-rapid amplification of cDNA ends (5'-RACE), we confirmed that miR1832 targets the cytochrome P450 gene TaP450-7A, which is upregulated by LT and negatively regulates SD. Finally, physiological and biochemical analysis further demonstrated that the TaDof-2D-miR1832-TaP450-7A module appears to participate in LT-induced dormancy release by influencing α-amylase activity as well as the abscisic acid (ABA) and gibberellin (GA) pathways. These findings not only demonstrate a new regulatory mechanism underlying LT-induced dormancy release, but also provide promising genetic resources and molecular markers for breeding wheat varieties with optimal dormancy levels.
Gao et al. (2026) studied this question.