“Within the phylum Bacteroidetes, the gyrB gene, encoding for the B subunit of the DNA gyrase, has been used as a phylogenetic marker for several genera closely related to Flavobacterium. Selleck A 769662 The phylogenies of the complete 16S rRNA gene and the gyrB gene were compared for 33 Antarctic Flavobacterium isolates and 23 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 15 Flavobacterium groups, including at least 13 potentially new species together with one group of isolates probably belonging to the species Flavobacterium micromati and one group close to Flavobacterium gelidilacus. Heterotrophic bacterial communities in Antarctica are highly diverse in aquatic (Bowman et al., 2000; Van Trappen et al., 2002) as well as in terrestrial (Aislabie et al., 2006; Babalola et al., 2009) habitats. A genus that has been isolated
often from these environments is Flavobacterium (Brambilla et al., 2001; Humphry et al., 2001; Van Trappen et al., 2002), and several novel Flavobacterium species were described from Antarctic habitats (Flavobacterium gelidilacus, Flavobacterium gillisiae, Flavobacterium hibernum, find more Flavobacterium micromati, Flavobacterium psychrolimnae, Flavobacterium xanthum) or other cold environments (Flavobacterium xinjangense and Flavobacterium omnivorum). Other Flavobacterium species have been mainly isolated from freshwater fish (Flavobacterium all branchiophilum, Flavobacterium columnare, Flavobacterium psychrophilum), temperate freshwater (Flavobacterium aquatile, Flavobacterium flevense, Flavobacterium saccharophilum) and from soil (Flavobacterium johnsoniae, Flavobacterium pectinovorum). Most Flavobacterium species are psychrotolerant and as they are able to hydrolyse several carbohydrates and biomacromolecules
such as gelatine, casein and starch, they might be of biotechnological importance (Bernardet & Bowman, 2006). The family Flavobacteriaceae (phylum Bacteroidetes) as well as the genus Flavobacterium have been revised and added to repeatedly over the years (Vandamme et al., 1994; Bernardet et al., 1996, 2002). Flavobacterium was created in 1923 for all bacteria that formed yellow- or orange-pigmented colonies and weakly produced acid from carbohydrates (Bergey et al., 1923). This broadly defined and taxonomically heterogeneous group was further refined using phenotypic characteristics (Holmes et al., 1984) and the determination of guanine plus cytosine (G+C) content (Reichenbach, 1989). The introduction of the 16S rRNA gene oligonucleotide catalogue (Paster et al.