Current Insights into mA RNA Methylation and Its Emerging Role in Plant Circadian Clock.

-adenosine methylation (mA) is a prevalent form of RNA modification found in the expressed transcripts of many eukaryotic organisms. Moreover, mA 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 mA-binding proteins. Over the past decade, the mA 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, mA 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, mA 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 mA modification and its various roles in the regulation of RNA. We discuss the potential role of mA 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 mA RNA regulation and its role in plant circadian clocks will contribute to a greater understanding of the plant circadian clock.