ALKBH9C, a potential RNA m6A demethylase, regulates the response of Arabidopsis to abiotic stresses and abscisic acid

Abstract Although several studies have shown that AlkB homolog (ALKBH) proteins are potential RNA demethylases (referred to as ‘erasers’), biological functions of only a few ALKBH proteins have been characterized to date. In this study, we determined the function of ALKBH9C (At4g36090) in seed germination and seedling growth of Arabidopsis thaliana in response to abiotic stress and abscisic acid (ABA). Seed germination of the alkbh9c mutant was delayed in response to salt, drought, cold and ABA. Moreover, seedling growth of the mutant was repressed under salt stress or ABA but enhanced under drought conditions. Notably, the stress‐responsive phenotypes were associated with the altered expression of several m 6 A‐modified transcripts related to salt, drought or ABA response. Global m 6 A levels were increased in the alkbh9c mutant, and ALKBH9C bound to m 6 A‐modified RNAs and had in vitro m 6 A demethylase activity, suggesting its potential role as an m 6 A eraser. The m 6 A levels in several stress‐responsive genes were increased in the alkbh9c mutant, and the stability of m 6 A‐modified transcripts was altered in the mutant. Collectively, our results suggest that m 6 A eraser ALKBH9C is crucial for seed germination and seedling growth of Arabidopsis in response to abiotic stresses or ABA via affecting the stability of stress‐responsive transcripts.