CmERF5‐CmRAP2.3 transcriptional cascade positively regulates waterlogging tolerance in Chrysanthemum morifolium

Summary Waterlogging stress affects plant growth by limiting root respiration and reducing yield and economic value. Therefore, identifying genes involved in regulating waterlogging stress is vital. This study reports the ethylene‐responsive VII transcription factor ( CmRAP2.3 ) in the chrysanthemum. Subcellular localization and transactivation assay analyses revealed that CmRAP2.3 was localized in the nucleus and possessed transactivation activity. Overexpression of CmRAP2.3 in chrysanthemum was found to enhance waterlogging tolerance by decreasing reactive oxygen species (ROS) levels. Furthermore, we found that the transcription factor CmERF5 binds to GCC‐like motifs in the CmRAP2.3 promoter region and activates CmRAP2.3 expression. Additionally, CmERF5 overexpression maintained a low ROS level and improved chrysanthemum waterlogging tolerance. Taken together, this study shows a molecular mechanism by which CmERF5 transcriptionally activates CmRAP2.3 to reduce waterlogging stress via the ROS pathway in the chrysanthemum.