Comparative Analysis of Plastid RNA Editing in Nicotiana Species

Abstract

Transcripts of plastids in higher plants are highly modified by C-to-U RNA editing. It exhibits extraordinary phylogenetic dynamics leading to species-specific editing site patterns. Nicotiana tabacum (tobacco) is a natural amphidiploid derived from ancestors of N. sylvestris and N. tomentosiformis. These Nicotiana species offer a significant advantage for evolutional studies of RNA editing in higher plant plastids. Analysis of the first editing site in ndhD mRNAs in these species revealed that editing efficiency in N. tomentosiformis is lower than those in N. tabacum and N. sylvestris, but this level of editing is enough to express the ndhD gene. This result suggests that decrease of editing efficiency in N. tomentosiformis might be due to a defect in function of its CRR4 ortholog. To study this possibility, we are investigating whether CRR4 orthologs have different efficiency in its function among Nicotiana species.