Nocardiopsis terrae sp. nov., a halophilic actinomycete isolated from saline soil

Abstract

A Gram-positive, moderately halophilic, facultatively alkaliphilic, catalase- and oxidase-positive, obligately aerobic, filamentous actinomycete strain, designated YIM 90022(T), was isolated from saline soil collected from the Qaidam Basin, north-west China. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the new isolate was a member of the genus Nocardiopsis and the sequence similarities between the isolate and the type strains of members of the genus Nocardiopsis were in the range of 95.1-98.7%. Phenotypic and chemotaxonomic properties of this organism also indicated that strain YIM 90022(T) was a member of the genus Nocardiopsis. The strain grew well on most of the media tested, producing yellow-white to deep brown substrate mycelium and white aerial mycelium. Light gray to deep brown diffusible pigments were produced. The substrate mycelium was well developed and fragmented with age; the aerial mycelium produced long, straight to flexuous spore chains with non-motile, smooth-surfaced, rod-shaped spores on them. The strain grew in the presence of 1-15% (w/v) total salts (optimum, 3-5%) and at pH 6.0-10.5 (optimum, pH 8.5) and 10-45 degrees C (optimum, 30 degrees C). Whole-cell hydrolysates of strain YIM 90022(T) contained meso-diaminopimelic acid and no diagnostic sugars. The predominant menaquinones were MK-10(H(4)), MK-9(H(8)), MK-10(H(6)) and MK-10(H(8)). Polar lipids comprised diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol and phosphatidylmethylethanolamine. The major cellular fatty acids were iso-C(16:0), anteiso-C(17:0), 10-methyl-C(18:0) and 10-methyl-C(17:0). The DNA G + C content of strain YIM 90022(T) was 71.5 mol%. The combination of phylogenetic analysis, DNA-DNA relatedness data, phenotypic characteristics and chemotaxonomic data supported the suggestion that strain YIM 90022(T) represents a new species of the genus Nocardiopsis, for which the name Nocardiopsis terrae sp. nov. is proposed. The type strain is YIM 90022(T) (=CCTCC AA 208011(T) =KCTC 19431(T)).