Like ODB1 in mitochondria, maize WHY1 associated with DNA sequences throughout the plastid genome. In addition, maize WHY1 was shown to be required for efficient splicing of the plastid atpF transcript whose intron it bound, and it was essential for correct ribosome biogenesis. In barley, WHY1 was similarly found to bind intron-containing plastid transcripts and to affect atpF splicing; DNA association in vivo was not seen for the majority of WHY1