XVI International Botanical Congess

Charophytes have been suggested to be paraphyletic to land plants (embryophytes), based on investigations of ultrastructural and genomic structural features. Their exact relationships to land plants, however, remain controversial, despite the analyses of chloroplast rbcL and nuclear 18S rRNA sequence data. We have investigated the multi-cistronic operon psbB-psbT-(psbN)-psbH-petB-petD and presence/absence of introns in the genes petB and petD, all of which are present among all examined embryophytes, in the chloroplast genome of all five lineages of charophytes. These genomic structural features are informative in resolving relationships among the five charophyte lineages and their relationships to land plants.