Pedobacter jamesrossensis sp. nov., Pedobacter lithocola sp. nov., Pedobacter mendelii sp. nov. and Pedobacter petrophilus sp. nov., isolated from the Antarctic environment

A taxonomic study performed on 17 Gram-stain-negative rod-shaped bacterial strains originating from the Antarctic environment is described. Initial phylogenetic analysis using 16S rRNA gene sequencing differentiated the strains into four groups belonging to the genus Pedobacter but they were separated from all hitherto described Pedobacter species. Group I (n=8) was closest to Pedobacter aquatilis (97.8% 16S rRNA gene sequence similarity). Group II (n=2) and group III (n=4) were closely related (98.8% 16S rRNA gene sequence similarity) and had Pedobacter jejuensis as their common nearest neighbour. Group IV (n=3) was distantly delineated from the remaining Pedobacter species. Differentiation of the analysed strains into four clusters was further confirmed by repetitive sequence-based PCR fingerprinting, ribotyping, DNA-DNA hybridization and phenotypic traits. Common to representative strains for the four groups were the presence of major menaquinone MK-7, sym-homospermidine as the major polyamine, phosphatidylethanolamine, two unidentified lipids (L2, L5) and an unidentified aminolipid (AL2) as the major polar lipids, presence of an alkali-stable lipid, and C-16:1 omega 7c/C-16:1 omega 6c (summed feature 3), iso-C-15:0 and iso-C-17: 0 3-OH as the major fatty acids, which corresponded to characteristics of the genus Pedobacter. The obtained results showed that the strains analysed represent four novel species of the genus Pedobacter, for which the names Pedobacter jamesrossensis sp. nov. (type strain CCM 8689(T)=LMG 29684(T)), Pedobacter lithocola sp. nov. (CCM 8691(T)=LMG 29685(T)), Pedobacter mendelii sp. nov. (CCM 8685(T) =LMG 29688(T)) and Pedobacter petrophilus sp. nov. (CCM 8687(T)=LMG 29686(T)) are proposed