Description of nine novel psychrophilic Pseudarthrobacter species from glaciers

Eleven glacier-derived bacterial strains, represented by the type strains HZ3 T , TMT1-37 T , TMS2-18 T , TMN-17 T , TMN-24 T , MDT1-20 T , MDT3-30 T , HLT3-6 T and MDT3-24 T , were isolated from cryoconite samples collected from glaciers in China. These strains comprised nine genomic species because TMN-24 T and TMT1-38, and MDT1-20 T and HLT1-8, respectively, represented two conspecific pairs. The 16S rRNA gene sequence identities among the 11 strains ranged from 98.68 to 100% and their closest phylogenetic neighbours were species of the genus Pseudarthrobacter . Phylogenomic analysis based on 81 concatenated core genes placed the 11 strains within the genus Pseudarthrobacter and resolved them into distinct lineages. Pairwise average nucleotide identity values between the novel strains and their closest relatives were 80.10–94.80%, and the corresponding digital DNA–DNA hybridization values were 22.6–59.5%, all below the accepted species delineation thresholds, except for the two conspecific strain pairs TMN-24 T /TMT1-38 and MDT1-20 T /HLT1-8. The genomic DNA G+C contents of the type strains ranged from 64.6 to 66.9 mol%. Differential phenotypic characteristics further supported their separation from recognized species of the genus. On the basis of the polyphasic taxonomic evidence, nine novel species of the genus Pseudarthrobacter are proposed: Pseudarthrobacter ribosi sp. nov. (type strain HZ3 T =CGMCC 1.9263 T =NBRC 117320 T ), Pseudarthrobacter leeuwenhoeki sp. nov. (TMT1-37 T =CGMCC 1.9345 T =NBRC 117321 T ), Pseudarthrobacter linnaei sp. nov. (TMS2-18 T =CGMCC 1.9408 T =NBRC 117322 T ), Pseudarthrobacter adonitolis sp. nov. (TMN-17 T =CGMCC 1.9575 T =NBRC 117323 T ), Pseudarthrobacter kochi sp. nov. (TMN-24 T =CGMCC 1.9581 T =NBRC 117324 T ), Pseudarthrobacter woesei sp. nov. (MDT1-20 T =CGMCC 1.9798 T =NBRC 117325 T ), Pseudarthrobacter xylosi sp. nov. (MDT3-30 T =CGMCC 1.9921 T =NBRC 117328 T ), Pseudarthrobacter lactosi sp. nov. (HLT3-6 T =CGMCC 1.10016 T =NBRC 117330 T ) and Pseudarthrobacter arbutini sp. nov. (MDT3-24 T =CGMCC 1.9916 T =JCM 38166 T ).