m6A RNA methylation attenuates thermotolerance in Arabidopsis

Heat stress severely affects plant growth, causing significant crop yield losses. To counteract this, plants employ adaptive strategies, including chromatin and transcriptional regulation of heat stress-related genes. However, the role of RNA methylation in heat stress response remains unclear. This study identifies m6A RNA methylation as a negative regulator of thermotolerance in Arabidopsis. Loss of m6A modification enhances resilience to heat stress by increasing transcript levels of heat-responsive genes and stabilizing their mRNAs. Upon heat shock, plants transiently reduce m6A levels by modulating key methylation machinery genes. This m6A deficiency enriches the H3K4me3 histone mark at heat-responsive gene loci, boosting their transcription. The combined effect of m6A-regulated chromatin changes and mRNA stability facilitates the accumulation of heat shock proteins essential for cellular protection and stress response. These findings reveal an interplay between m6A RNA methylation and histone modifications, forming a regulatory network that fine-tunes gene expression during heat stress. This novel mechanism highlights m6A as a critical regulator of plant thermotolerance, offering a promising target for improving heat stress resilience in crops.