Plant-type pentatricopeptide repeat proteins with a DYW domain drive C-to-U RNA editing in .

RNA editing converting cytidines into uridines is a hallmark of gene expression in land plant chloroplasts and mitochondria. Pentatricopeptide repeat (PPR) proteins have a key role in target recognition, but the functional editosome in the plant organelles has remained elusive. Here we show that individual DYW-type PPR proteins alone can perform efficient C-to-U editing in reproducing the moss mitochondrial editing. Single amino acid exchanges in the DYW domain abolish RNA editing, confirming it as the functional cytidine deaminase. The modification of RNA targets and the identification of numerous off-targets in the transcriptome reveal nucleotide identities critical for RNA recognition and cytidine conversion. The straightforward amenability of the new setup will accelerate future studies on RNA target recognition through PPRs, on the C-to-U editing deamination machinery and towards future establishment of transcript editing in other genetic systems.