Nocardia heshunensis sp nov., an actinomycete isolated from soil

A novel Gram-stain-positive, aerobic, non-motile and acid-fast actinomycete strain, designated CFH S0067(T), was isolated from a soil sample collected from Heshun old town in Tengchong, Yunnan province, in south-west PR China. The taxonomic position of strain CFH S0067(T) was studied in detail using a polyphasic approach. Phylogenetic analysis, based on 16S rRNA gene sequences, revealed that strain CFH S0067(T) belongs to the genus Nocardia and is closely related to Nocardia concava JCM 12351(T) (99.3% similarity), forming a separated branch with this type strain. However, the strain shared 96.0% gyrB gene sequence similarity with N. concava JCM 12351(T). Furthermore, DNA-DNA hybridization showed 56.5 +/- 0.6% DNA relatedness between the novel strain and N. concava JCM 12351(T). The whole-cell hydrolysates contained mesodiaminopimelic acid (type IV) and arabinose, galactose, fructose and mannose. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside and one unidentified lipid. Strain CFH S0067(T) contained MK-8 (H4 omega-cycl) as the predominant menaquinone. C-16:0, summed feature 3 (C-16:1 omega 7c and/or C-16:1 omega 6c), C-18:1 omega 9c and C-18:0 10-methyl (TBSA) were the major cellular fatty acids. Mycolic acids were also detected. The G+C content of the genomic DNA was determined to be 66.9 mol%. A combination of the low DNA-DNA hybridization values and phenotypic properties demonstrated that strain CFH S0067(T) is clearly distinguishable from its most closely related strain, N. concava JCM 12351(T). On the basis of this polyphasic study, it is concluded that strain CFH S0067(T) should be considered to represent a novel species of the genus Nocardia, for which the name Nocardia heshunensis sp. nov. is proposed. The type strain is CFH S0067(T) (=DSM 46764(T) =JCM 30085(T)).