Geodermatophilus ruber sp. nov., isolated from rhizosphere soil of a medicinal plant

Abstract

A novel actinobacterial strain, designated CPCC 201356T, was isolated from a rhizosphere soil sample of the medicinal plantAstragalus membranaceusand subjected to a polyphasic taxonomic analysis. Good growth occurred at 20–32 °C, at pH 7.0–7.5 and with 0–1 % (w/v) NaCl. Colonies on R2A and ISP 2 agar were light red to red, round and lacked aerial mycelium; cells adhered to the agar. The peptidoglycan containedmeso-diaminopimelic acid as the diagnostic diamino acid. The predominant menaquinones were MK-9(H4) and MK-9. Polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine and two unknown phospholipids. The major cellular fatty acids were iso-C16 : 0, iso-C15 : 0and C17 : 1ω8c. The G+C content of the genomic DNA was 72.8 mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain CPCC 201356Tbelonged to the familyGeodermatophilaceaeand consistently formed a distinct sub-branch withGeodermatophilus obscurusDSM 43160T. The organism showed 16S rRNA gene sequence similarity of 97.7 % withG. obscurusDSM 43160T. DNA–DNA hybridization between strain CPCC 201356TandG. obscurusDSM 43160Twas 17.4 %. On the basis of evidence from this polyphasic taxonomic study, a novel species,Geodermatophilus rubersp. nov., is proposed; the type strain is CPCC 201356T(=DSM 45317T=CCM 7619T).