Abstract

m6A, one of the most abundant mRNA modifications, has been associated with various metabolic processes in plants. Here we show that m6A also plays a role in miRNA biogenesis in Arabidopsis thaliana. Significant reductions in plant m6A/MTA levels results in lower accumulation of miRNAs whereas pri-miRNA levels tend to be higher in such plants. m6A-IP Seq and MTA-GFP RIP were used to show that many pri-miRNAs are m6A methylated and are bound by MTA, further demonstrating that pri-miRNAs can also be substrates for m6A methylation by MTA. We report that MTA interacts with RNA Pol II, supporting the assumption that m6A methylation is a co-transcriptional process, and also identify TGH, a known miRNA biogenesis related protein, as a novel protein that interacts with MTA. Finally, reduced levels of miR393b may partially explain the strong auxin insensitivity seen in Arabidopsis plants with reduced m6A levels.