sp. nov., sp. nov. and sp. nov., three novel carbon monoxide-oxidizing Halobacteria from saline crusts and soils.

Three novel carbon monoxide-oxidizing Halobacteria were isolated from Bonneville Salt Flats (Utah, USA) salt crusts and nearby saline soils. Phylogenetic analysis of 16S rRNA gene sequences revealed that strains PCN9, WSA2 and WSH3 belong to the genera , and , respectively. Strains PCN9, WSA2 and WSH3 grew optimally at 40 °C (PCN9) or 50 °C (WSA2, WSH3). NaCl optima were 3 M (PCN9, WSA2) or 4 M NaCl (WSH3). Carbon monoxide was oxidized by all isolates, each of which contained a molybdenum-dependent CO dehydrogenase. G+C contents for the three respective isolates were 66.75, 67.62, and 63.97 mol% as derived from genome analyses. The closest phylogenetic relatives for PCN9, WSA2 and WSH3 were A1, D90 and EB27 with 98.71, 98.19 and 95.95 % 16S rRNA gene sequence similarities, respectively. Genome comparisons of PCN9 with A1 yielded an average nucleotide identity (ANI) of 82.0% and a digital DNA-DNA hybridization (dDDH) value of 25.7 %; comparisons of WSA2 with D90 yielded ANI and dDDH values of 86.34 and 31.1 %, respectively. The ANI value for a comparison of WSH3 with EB27 was 75.2 %. Physiological, biochemical, genetic and genomic characteristics of PCN9, WSA2 and WSH3 differentiated them from their closest phylogenetic neighbours and indicated that they represent novel species for which the names , and are proposed, respectively. The type strains are PCN9 (=JCM 32472=LMG 31022=ATCC TSD-126), WSA2 (=JCM 32473=ATCC TSD-127) and WSH3 (=JCM 32474=ATCC TSD-128).