N6-adenosine methylation (m6A) is a prevalent form of RNA modification found in the expressed transcripts of many eukaryotic organisms. Moreover, m6A 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 m6A-binding proteins. Over the past decade, the m6A 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, m6A 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, m6A 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 m6A modification and its various roles in the regulation of RNA. We discuss the potential role of m6A 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 m6A RNA regulation and its role in plant circadian clocks will contribute to a greater understanding of the plant circadian clock.
Keywords: FIONA1; MTA; MTB; circadian clock; epitranscriptome; m6A eraser; m6A methylation; m6A reader; m6A writer.