Investigation of wheat cold response pathway regulated by TaICE41 and TaCBFⅣd-B9 through Brachypodium distachyon transformation

Wheat (Triticum aestivum L.), a major global crop, is vulnerable to freezing stress, particularly during late spring frosts. Enhancing freezing tolerance through cold acclimation, primarily via the ICE-CBF-COR pathway, is crucial for improving wheat productivity. This study focuses on identifying genes regulated by the ICE-CBF pathway and those that function independently in response to freezing stress. TaICE41 and TaCBFⅣd-B9, two key genes associated with cold tolerance, were cloned and analyzed for their phylogenetic characteristics and subcellular localization. Transgenic Brachypodium distachyon overexpressing these genes demonstrated enhanced freezing tolerance, with increased survival rates and proline content, compared to wild-type plants. RNA-seq analysis revealed distinct gene expression profiles under cold stress, highlighting both shared and unique pathways regulated by ICE41 and CBF. Notably, the TaICE41-overexpressing lines exhibited upregulation of genes involved in phenylpropanoid biosynthesis and starch-sucrose metabolism, contributing to stress response. This study provides new insights into the ICE-CBF pathway and its role in cold tolerance, emphasizing the importance of understanding both ICE-CBF-regulated and independent cold-responsive genes for improving freezing tolerance in crops.