Current Insights into m 6 A RNA Methylation and Its Emerging Role in Plant Circadian Clock.

N6 -adenosine methylation (m 6 A) is a prevalent form of RNA modification found in the expressed transcripts of many eukaryotic organisms. Moreover, m 6 A methylation is a dynamic and reversible process that requires the functioning of various proteins and their complexes that are evolutionarily conserved between species and include methylases, demethylases, and m 6 A-binding proteins. Over the past decade, the m 6 A methylation process in plants has been extensively studied and the understanding thereof has drastically increased, although the regulatory function of some components relies on information derived from animal systems. Notably, m 6 A has been found to be involved in a variety of factors in RNA processing, such as RNA stability, alternative polyadenylation, and miRNA regulation. The circadian clock in plants is a molecular timekeeping system that regulates the daily and rhythmic activity of many cellular and physiological processes in response to environmental changes such as the day-night cycle. The circadian clock regulates the rhythmic expression of genes through post-transcriptional regulation of mRNA. Recently, m 6 A methylation has emerged as an additional layer of post-transcriptional regulation that is necessary for the proper functioning of the plant circadian clock. In this review, we have compiled and summarized recent insights into the molecular mechanisms behind m 6 A modification and its various roles in the regulation of RNA. We discuss the potential role of m 6 A modification in regulating the plant circadian clock and outline potential future directions for the study of mRNA methylation in plants. A deeper understanding of the mechanism of m 6 A RNA regulation and its role in plant circadian clocks will contribute to a greater understanding of the plant circadian clock.