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Matthew Quinn, Olivia Anne Blenner-Hassett, Lochlan Breckenridge & Lyle G. Whyte
Guyparkeria haloeurypsychrophila sp. nov., a lithoautotrophic polyextremophile isolated from a sub-zero hypersaline spring Mars Analog
Two eurypsychrophilic sulfur oxidizing bacterial strains (LHSS19-1T and GHLCS8-2) were isolated from High Arctic hypersaline sulfur spring sediment samples collected from the Lost Hammer and Gypsum Hill spring systems on Axel Heiberg Island, Nunavut, Canada. The strains were obligate chemolithoautotrophs, utilizing reduced sulfur compounds (thiosulfate, sulphide, tetrathionate and elementary sulfur) as electron donors and energy sources. Lithoautotrophic growth on thiosulfate was observed at -2°– 37°C, pH 6.5 – 9.5, and NaCl concentrations of 1–20%. The DNA G+C content of the draft genome sequences was 64.59-64.74 mol%. Phylogenetic analyses based on 16S rRNA gene sequences, genome pairwise comparisons, 92 single-copy core genes and type IA ribulose bisphospate carboxylase/oxygenase amino acyl sequences indicated that both strains together form a distinct monophyletic clade within the genus Guyparkeria. Moreover, in silico DNA-DNA hybridization values, orthologous average nucleotide identity and average amino acid identity values calculated between each strain and the closest related type strains were ≤ 69.10%, 87.83% and 90.37%, respectively. The genomes of both strains encoded high O2 affinity cbb3-type cytochrome c oxidase genes but distinctively lacked a complete set of aa3 type cytochrome c oxidase genes. Based on phenotypic and genotypic results, we propose that strain LHSS19-1T and GHLCS8-2 represent a novel species within the genus Guyparkeria, for which the name Guyparkeria haloeurypsychrophila sp. nov. is proposed. The type strain is LHSS19-1T (=NCTC 15100T=DSM 117890T).
