Chromatin Accessibility and Translational Landscapes of Bermudagrass (Cynodon dactylon) Under Chilling Stress

ABSTRACT Cold tolerance in plants is a complex trait regulated by a network of transcription factors (TFs) and their downstream genes. While C‐repeat binding factors (CBFs) are well‐known for their role in cold tolerance, other regulatory networks remain largely unexplored. This study utilizes a combined approach of Assay for Transposase‐Accessible Chromatin with Sequencing (ATAC‐seq) and RNA‐seq to identify cold‐responsive TFs in Cynodon dactylon (Bermudagrass), a species widely grown in southern China but limited by cold stress. Early‐stage cold stress was found to induce dynamic changes in 331 differentially accessible regions (DARs), with over 45% located in gene promoter regions. Key TFs, including CAMTA1, CAMTA2, WRKY43, WRKY48, WRKY21, and DREB1G, were associated with gained DARs, highlighting their roles in cold response regulation. In contrast, several Heat Shock Factor (HSF) family members, such as HSFA6B, HSFB2A, HSFC1, and HSFB2B, were linked to lost DARs, underscoring their involvement in cold stress regulation. The correlation between chromatin accessibility and gene expression emphasizes the critical role of TFs in plant cold stress adaptation. This study highlights the potential of ATAC‐seq and RNA‐seq as powerful tools for uncovering novel TFs essential for cold tolerance in plants, offering insights for future research and breeding efforts.