AbstractN6‐methyladenosine (m6A) is an abundant methylation mark in eukaryotic mRNAs. It is installed and removed by methyltransferases (“writers”) and demethylases (“erasers”), respectively. A recent study has demonstrated that alpha‐ketoglutarate‐dependent dioxygenase homolog 10B (ALKBH10B) is an mRNA m6A eraser affecting floral transition in Arabidopsis thaliana. However, the roles of m6A eraser proteins, including ALKHB10B, in plant adaptation to abiotic stresses are largely unknown. In this study, we aimed to determine the role of ALKBH10B in the response of A. thaliana to abiotic stresses and abscisic acid (ABA). The m6A level increased in response to salt stress, and m6A levels in alkbh10b mutants were higher than those in the wild‐type under both normal and salt stress conditions. Germination of alkbh10b mutant seeds was markedly delayed under salt stress but not under dehydration, cold, or ABA conditions. Seedling growth and survival rate of alkbh10b mutants were enhanced under salt stress. Notably, salt‐tolerant phenotypes of alkbh10b mutants were correlated with decreased levels of several m6A‐modified genes, including ATAF1, BGLU22, and MYB73, which are negative effectors of salt stress tolerance. In response to ABA, both seedling and root growth of alkbh10b mutants were inhibited via upregulating ABA signaling‐related genes, including ABI3 and ABI4. Collectively, these findings indicate that ALKBH10B‐mediated m6A demethylation affects the transcript levels of stress‐responsive genes, which are important for seed germination, seedling growth, and survival of Arabidopsis thaliana in response to salt stress or ABA.
