ERF3 of Myricaria laxiflora contributes to waterlogging tolerance by regulating ethylene biosynthesis through transcriptional regulation of MylACO1

Ethylene-responsive factors (ERFs) act as pivotal regulators during plant responses to waterlogging, but the specific molecular pathways orchestrating flood adaptation in woody species are still not fully comprehended. Here, we functionally characterized MylERF3, a nucleus-localized AP2/ERF transcription factor from the highly flood-tolerant shrub Myricaria laxiflora . Expression profiling revealed that MylERF3 is rapidly induced by waterlogging stress. Overexpression of MylERF3 in Arabidopsis thaliana markedly enhanced tolerance to waterlogged conditions. Further metabolic and transcriptomic analyses indicated that waterlogging stimulates ethylene emission in M. laxiflora , a process fundamentally driven by the induced expression of MylACO1 , which encodes a crucial ethylene biosynthesis enzyme. MylERF3 directly targets and activates MylACO1 transcription by binding within its promoter. Consistently, MylERF3 transgenic lines exhibited elevated levels of ethylene production and ACO enzyme activity, along with up-regulation of ethylene biosynthesis-related genes. Taken together, these results demonstrate that MylERF3 functions positively in waterlogging tolerance by modulation of ethylene biosynthesis via regulating MylACO1 , thereby offering new insights into the transcriptional regulation of flood adaptation in woody plants.