ECT10 is an m⁶A reader that negatively regulates the drought stress response in Arabidopsis by modulating mRNA...

N⁶-methyladenosine (m⁶A) modification occurs prevalently in eukaryotic mRNAs and is a key epitranscriptomic mechanism regulating plant development and stress responses. The m⁶A mark is interpreted by 'readers' that recognize and bind to m⁶A-modified RNAs. Recent studies highlight Evolutionarily Conserved C-terminal region (ECT) proteins as m⁶A readers in various plant species. However, the functions of many ECT proteins remain unknown. Therefore, this study aims to determine the role of ECT10 as an m⁶A reader and to evaluate its function in drought stress response in Arabidopsis. The electrophoretic mobility shift assay demonstrated that ECT10 specifically binds to m⁶A-modified RNAs but not to m⁵C-modified RNAs in vitro. The expression of ECT10 decreased markedly under drought stress conditions. The ect10 loss-of-function mutant exhibited reduced sensitivity to drought stress. Complementation lines expressing the native ECT10 in the ect10 mutant background restored the wild-type phenotype, while lines expressing the mutant mECT10, harboring substitutions at two critical amino acid residues, failed to rescue the phenotype. ECT10 regulated the expression of several m⁶A-modified positive or negative regulators of the drought stress response by modulating their stability through direct binding to these m⁶A-modified transcripts in planta. Collectively, these findings establish ECT10 as a novel m⁶A reader crucial for drought stress response by modulating mRNA stability.