Nature Plants 2, 16163 (2016); published 3 November 2016; corrected 12 December 2016.

In the version of this Review originally published, the following NSF grants should have been acknowledged: MCB-1252370 and MCB-1608392. This has been corrected in all versions of the Review. In addition, a typographical error in the section ’Key remaining questions for this field’ has been amended so that the sentence reads: “What RNA quality control mechanisms drive transcripts into RNA interference (RNAi) and thus the non-canonical RdDM pathways?”