Arabidopsis m 6 A demethylase activity modulates viral infection of a plant virus and the m 6 A abundance in its genomic RNAs

Significance N 6 -methyladenosine (m 6 A) modification has been found to constitute an important regulatory mechanism in RNA biology. Unlike mammals and yeast, no component of the m 6 A cellular machinery has been described in plants at present. Although the influence of the m6A cellular machinery has been suspected to occur in the plant virus cycle, it has never been proved. Here we have identified a plant protein with m 6 A demethylase activity (atALKBH9B) and demonstrate that this protein removes m 6 A modification from RNA in vitro. Remarkably, we found that m 6 A abundance on the viral genome of alfalfa mosaic virus is influenced by atALKBH9B activity and regulates viral infection. This study extends the vast repertoire that plants exploit to control cytoplasmic-replicating RNA viruses.