RNA methyltransferases in plants: Breakthroughs in function and evolution

Each day it is becoming increasingly difficult not to notice the completely new, fast growing, extremely intricate and challenging world of epitranscriptomics as the understanding of RNA methylation is expanding at a hasty rate. Writers (methyltransferases), erasers (demethylases) and readers (RNA-binding proteins) are responsible for adding, removing and recognising methyl groups on RNA, respectively. Several methyltransferases identified in plants are now being investigated and recent studies have shown a connection between RNA-methyltransferases (RNA-MTases) and stress and development processes. However, compared to their animal and bacteria coun-terparts, the understanding of RNA methyltransferases is still incipient, particularly those located in organelles. Comparative and systematic analyses allowed the tracing of the evolution of these enzymes suggesting the ex-istence of several methyltransferases yet to be characterised. This review outlines the functions of plant nuclear and organellar RNA-MTases in plant development and stress responses and the comparative and evolutionary discoveries made on RNA-MTases across kingdoms.

Automated summary

The field of epitranscriptomics, specifically the understanding of RNA methylation, is rapidly expanding and becoming increasingly complex and challenging. Methyltransferases, demethylases, and RNA-binding proteins play crucial roles in adding, removing, and recognizing methyl groups on RNA. Plant methyltransferases have been identified and linked to stress and development processes, but the understanding of these enzymes, particularly those located in organelles, is still in its early stages. Comparative and evolutionary analyses have revealed the existence of multiple yet uncharacterized methyltransferases, and this review discusses the functions of nuclear and organellar RNA methyltransferases in plant development and stress responses, as well as the discoveries made across different kingdoms.