Methyl-CpG-binding domain protein AtMBD1 interacts with abscisic acid (ABA) receptor PYL5 and regulates transcriptional response to ABA in Arabidopsis

DNA methylation plays crucial role in regulating gene expression in eukaryotic organisms. Methyl-CpG-binding domain (MBD) proteins act as readers of DNA methylation and influence gene expression. While several MBD proteins have been well characterized, the functional mechanisms of many plant MBD proteins remain unclear. In this study, we focus on elucidating the role of the Arabidopsis thaliana Methyl-CpG Binding Domain protein AtMBD1. Using AtMBD1 as bait in a yeast two-hybrid screen, we identified an interaction between AtMBD1 and the abscisic acid (ABA) receptor PYL5. This interaction was validated using BiFC (Bimolecular Fluorescence Complementation) and FRET (Fluorescence Resonance Energy Transfer) assay. Phenotypic and transcriptome analysis of atmbd1 , pyl5 knock-out mutants revealed an ABA-insensitive phenotype and diminished transcriptional response to ABA. Our results establish a link between a component of the ABA signaling pathway and AtMBD1; and therefore, suggest that MBD proteins are also involved in the hormonal response to abiotic stress.