Staleya guttiformis gen. nov., sp. nov. and Sulfitobacter brevis sp. nov., alpha-3-Proteobacteria from hypersaline, heliothermal and meromictic antarctic Ekho Lake.

Two Gram-negative, aerobic, pointed and budding bacteria were isolated from various depths of hypersaline, heliothermal and meromictic Ekho Lake (Vestfold Hills, East Antarctica). 16S rRNA gene sequence comparisons show the isolates to be phylogenetically close to the genera Sulfitobacter and Roseobacter. Cells can be motile and contain storage granules. Sulfite addition does not stimulate growth. Isolate EL-38T can produce bacteriochlorophyll a and has a weak requirement for sodium ions; polar lipids include phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine and an unidentified amino lipid, but not diphosphatidylgycerol. The dominant fatty acid is 18:1omega7c; other characteristic fatty acids are 3-OH 10:0, 3-OH 14:1, 16:0, 18:0, 18:2 and 19:1. The DNA base composition is 55.0-56.3 mol% G+C. Isolate EL-162T has an absolute requirement for sodium ions. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine and an unidentified amino lipid are present in the polar lipids. Dominant fatty acids of this isolate are 18:1omega7c and 18:1omega9c as well as 18:2 which is present as two isomers. Other characteristic fatty acids are 3-OH 10:0, 3-OH 14:1, 16:0 and 18:0. The G+C content is 57.9-58.1 mol%. Morphological, physiological and genotypic differences from related, thus far known genera support the description of Staleya guttiformis gen. nov. and sp. nov. with EL-38T (= DSM 11458T) as the type strain and of Sulfitobacter brevis sp. nov. with the type strain EL-162T (= DSM 11443T).