Abstract

A Gram-staining-positive, aerobic, non-motile, non-spore-forming and coccoid-shaped actinobacterial strain, designated YIM 730233T, was isolated from a sediment sample, collected from a hot spring in Tibet, China. Colonies were brownish, circular, smooth and convex. Strain YIM 730233Twas able to grow in the temperature range of 20–50 °C, pH 6.5–8.0 and in the presence of up to 1.0 % (w/v) NaCl. A comparison of the 16S rRNA gene sequence of strain YIM 730233Twith sequences of type strains of most closely related species ofMarmoricolashowed highest sequence similarities toMarmoricola bigeumensisMSL-05T(98.3%) andMarmoricola pocheonensisGsoil 818T(98.1%). The draft genome of strain YIM 730233Thad a size of 4 806 234 bp with a DNA G+C content of 72.1 mol%. The major fatty acids (>10 %) of strain YIM 730233Tmainly consisted of iso-C16 : 0, anteiso-C17 : 0and C18 : 1ω9c, typical of the genusMarmoricola. Strain YIM 730233Thad LL-2,6-diaminopimelic acid as the diagnostic diamino acid in the cell wall. The predominant isoprenoid quinone was MK-8(H4). The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, unidentified phospholipids and an unidentified lipid. DNA–DNA hybridizations between strain YIM 730233Tand type strains ofMarmoricola bigeumensisMSL-05TandMarmoricola pocheonensisGsoil 818Tresulted in similarity values of 21 and 19% respectively. Based on DNA–DNA hybridization results, together with the differentiating biochemical and chemotaxonomic features, showed that strain YIM 730233Trepresents a novelMarmoricolaspecies, for which the nameMarmoricola caldifontissp. nov. (type strain YIM 730233T=KCTC 49192T=CGMCC 4.7521T), is proposed.