Chloroplast DNA diversity in the cytoplasms of sugar beet and its related species

Chloroplast genomes of sugar beet (Beta vulgaris) and its five related species have been characterized by restriction enzyme analysis. B. vulgaris and B. maritima chloroplast (ct) DNAs share almost identical restriction patterns irrespective of restriction enzymes used, indicating a close relationship between the ctDNAs of these two species assigned to the section Vulgares. In contrast, ctDNAs from the other four species (B. trigyna, B. lomatogona, B. patellaris and B. procumbens) show clear differences. Thus, closely related species display more similar ctDNA fragment patterns than do distantly related ones. It was also demonstrated that variations in ctDNAs have occurred in the fragment carrying a putative gene (rps19) for ribosomal protein CS-19. These findings indicate that the taxonomic classification shows a parallel relation with the ctDNA diversity in Beta.