RNA m6A 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 (m6A) is crucial for plant stress responses, the specific role of m6A in salt tolerance remains unclearly defined. Here, we show that Arabidopsis mutants deficient in m6A writers or readers exhibit heightened salt sensitivity at both growth and physiological levels. Global m6A modification levels increase following salt stress which results in a significant elevation of m6A signature throughout the Arabidopsis transcriptome. Spatiotemporal analysis through standardized read density of MeRIP-seq uncovered a significant salt-induced redistribution of m6A modification patterns. More than 80% m6A 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 m6A modification levels. By associating with gene expression profiling, 840 salt-responsive genes display significant alterations in m6A enriched level and negative regulation pattern happens in most of genes. The salt responsive genes showing increased m6A methylation but significantly decreased expression are focused which representatively enriched in photosynthesis pathway, and this suppression due to mRNA decay mediated by m6A modification. Photosynthetic capacity and chloroplast apparatus are impaired in m6A-dependent manner under salt stress. These results clarify the biological functions of m6A modification in plant response to salinity and uncover the specific role of RNA metabolism based on dynamic change pattern of m6A modification to cope with salt stress.