The gyrB gene is a useful phylogenetic marker for exploring the diversity of flavobacterium strains isolated from terrestrial and aquatic habitats in Antarctica
Within the phylum Bacteroidetes, the gyrB gene, encoding for the B subunit of the DNA gyrase, has been used as phylogenetic marker for several genera closely related to Flavobacterium. The phylogenies of the complete 16S rRNA gene and the gyrB gene were compared for thirty-three Antarctic Flavobacterium isolates and twenty-three type strains from closely related Flavobacterium species. GyrB gene sequences provided a higher discriminatory power to distinguish between different Flavobacterium groups than 16S rRNA gene sequences. The gyrB gene is therefore a promising molecular marker for elucidating the phylogenetic relationships among Flavobacterium species and should be evaluated for all the other type strains of described Flavobacterium species. Combining the phylogeny of both genes, the new Antarctic Flavobacterium strains constitute fifteen Flavobacterium groups, including at least thirteen potentially new species together with one group of isolates probably belonging to the species F. micromati and one group close to F. gelidilacus
