Next Generation Sequencing (m6A-seq) Reveals RNA m6A Methylation Patterns During the floral transition of Arobidopsis

In this study, we identified METTL16 as an mRNA m6A methyltransferase that plays a vital role in the floral transition in Arabidopsis. Transcriptome-wide analysis of RNA methylome in the mettl16 mutant revealed that m6A modification enriched near the stop codon and within the 3ʹ untranslated region. Deficiency of METTL16 leads to decreases in m6A levels of approximately 471 transcripts, indicating that it is responsible for the methylation of a small group of mRNAs. The mettl16 mutant displayed an early flowering phenotype, and the level of FLOWERING LOCUS C (FLC) was markedly decreased in the mutant. Importantly, METTL16-mediated m6A methylation affects the splicing of FLC, thereby influencing its transcript level to regulate floral transition. Our study identified METTL16 as a novel m6A methyltransferase and suggests a close molecular link between METTL16-mediated m6A methylation and FLC splicing in flowering time control. The Arobidopsis Col-0 and mettl16 mutant seedling were collected at 3-week-old. And the RNA extracted from samples with three biological replicates was subjected to m6A and RNA sequencing. For data analysis, the 3-week-old seedling of Col-0 was used as reference sample to investigate the role of m6A in floral transition.