Duff, R. Joel .
Pervasive RNA editing in hornwort chloroplast and mitochondrial protein coding genes..
RNA editing of chloroplast and mitochondrial genomes has been identified in all major clades of land plants. The frequency of edited sites varies greatly between plant lineages but hornworts represent an extreme in the propensity for editing in both their chloroplast and mitochondrial genomes. A systematic search of 18 taxonomically diverse hornwort rbcL sequences reveals 34 editing sites. Combined with 20 known edited sites from Anthoceros formosae, the 54 total editing sites represent 33 C to T and 22 T to C nucleotide conversions. The edited positions are distributed evenly across taxa, with one exception, with each possessing from 16 to 26 edited sites. A single sample, Leiosporoceros, is demonstrated to lack edited sites entirely in its rbcL transcript. A similar analysis of a portion of the nad5 gene from the mitochondria reveals a similar pattern of editing though the frequency is much higher for all taxa. The nad5 sequence of Leiosporoceros is edited at 8 positions in 800 bp but this is at least a two-fold lower rate than any other hornwort that has been examined. The diverse taxa, number of edited sites, and low levels, of complete absence of, editing in a potentially basal hornwort suggest that hornworts may be useful tools in studying the evolution of RNA editing in plant organellar genomes.
1 - University of Akron, Biology Department, Akron, Ohio, 443225-3908, USA
Presentation Type: Paper
Location: Peruvian (Cliff Lodge)
Date: Wednesday, August 4th, 2004
Time: 1:30 PM