Trichome branching is regulated by the m6A reader ECT2 in Arabidopsis (OA)

Methylation at position N6 of adenosines (m6A) is the most abundant mRNA chemical modification. It influences gene activity at the post-transcriptional level and is thus important for development. m6A is decoded by reader proteins. While the repertoire of reader proteins has been extensively studied in animals, little is known about its biological relevance and evolutionary history in plants. In this study, Scutenaire et al., provide a comprehensive evolutionary characterization of reader proteins found in the green plant clade. Based on this analysis, they identified and selected ECT2, a putative m6A reader, for further functional analysis. They demonstrate that Arabidopsis ECT2 localizes in the cytoplasm, binds m6A-containing mRNA and likely controls mRNA fate by relocating to stress granules upon heat-stress. They further show that ECT2 m6A reader activity is required for normal trichome branching and regulation of endoreduplication in developing trichomes. Together, this study provides new insights in the molecular function of m6A readers in plants and suggests an extensive role for m6A in regulating physiological and developmental processes in plants. (Summary by Matthias Benoit) Plant Cell 10.1105/tpc.17.00854