RNA m ⁶ A Methylation Control Salt Response by Affecting Photosynthesis Capacity

Soil salinization is a major abiotic stress constraining global plant growth. Epigenetic regulation particularly RNA modifications like N6-methyladenosine (m ⁶ A) is crucial for plant stress responses, the specific role of m ⁶ A in salt tolerance remains unclearly defined. Here, we show that Arabidopsis mutants deficient in m ⁶ A writers or readers exhibit heightened salt sensitivity at both growth and physiological levels. Global m ⁶ A modification levels increase following salt stress which results in a significant elevation of m ⁶ A signature throughout the Arabidopsis transcriptome. Spatiotemporal analysis through standardized read density of MeRIP-seq uncovered a significant salt-induced redistribution of m ⁶ A modification patterns. More than 80% m ⁶ A reads locate around the stop codon within 3’-untranslated regions and tend to increase under salt stress. A total of 9,986 peaks aligned into 8,667 coding gene showing significant changes in m ⁶ A modification levels. By associating with gene expression profiling, 840 salt-responsive genes display significant alterations in m ⁶ A enriched level and negative regulation pattern happens in most of genes. The salt responsive genes showing increased m ⁶ A methylation but significantly decreased expression are focused which representatively enriched in photosynthesis pathway, and this suppression due to mRNA decay mediated by m ⁶ A modification. Photosynthetic capacity and chloroplast apparatus are impaired in m ⁶ A-dependent manner under salt stress. These results clarify the biological functions of m ⁶ A modification in plant response to salinity and uncover the specific role of RNA metabolism based on dynamic change pattern of m ⁶ A modification to cope with salt stress.