Key enzymes in N6-methyladenosine modification regulate plant stress tolerance by modulating mRNA stability

Abstract

m⁶A writer and eraser mutants exhibit contrasting stress-dependent responses, highlighting that m⁶A-mediated regulation modulates plant stress responses in a stress-type-specific manner. N⁶-methyladenosine (m⁶A) is the most prevalent internal RNA modification in eukaryotic mRNAs and plays important roles in plant development and abiotic stress responses. However, how distinct m⁶A regulatory components contribute to stress adaptation under a unified experimental framework remains incompletely understood. Here, we performed a comparative analysis of Arabidopsis thaliana loss-of-function mutants of core m⁶A regulators, including m⁶A methyltransferase (writer) mutants (atfip37-2 and atmtb) and m⁶A demethylase (eraser) mutants (atalkbh9b-1 and atalkbh10b), using parallel phenotypic, physiological, molecular, and transcriptomic approaches under matched conditions. Under normal growth conditions, all mutants exhibited reduced primary root length, lower fresh weight, and delayed flowering compared with wild-type plants. Under stress treatments, all mutants were more growth-compromised than the wild type, but the magnitude of inhibition differed among regulatory classes in a stress-type-dependent manner: writer mutants exhibited comparatively less overall growth inhibition than eraser mutants under mannitol-based osmotic stress, whereas eraser mutants showed comparatively milder growth inhibition than writer mutants under NaCl treatment. Transcript stability assays further suggested that disruption of m⁶A regulatory components is associated with altered stability of selected stress-responsive transcripts, including genes involved in ABA biosynthesis and signaling. Together, these results provide a comparative genetic framework linking m⁶A regulatory perturbation to drought- and salt-related responses and support a context-dependent role for post-transcriptional regulation in plant stress adaptation.

Keywords: Arabidopsis thaliana; Abiotic stress; Post-transcriptional regulation; m6A.