Frigoribacterium endophyticum sp. nov., an endophytic actinobacterium isolated from the root of Anabasis elatior (C. A. Mey.) Schischk

Abstract

A novel endophytic actinobacterium, designated EGI 6500707 T, was isolated from the surfacesterilized root of a halophyte Anabasis elatior (C. A. Mey.) Schischk collected from Urumqi, Xinjiang province, north-west China, and characterized using a polyphasic approach. Cells were Gram-stain-positive, non-motile, short rods and produced white colonies. Growth occurred at 10–45 °C (optimum 25–30 °C), at pH 5–10 (optimum pH 8) and in presence of 0–4% (w/v) NaCl (optimum 0–3%). The predominant menaquinone was MK-9. The diagnostic phospholipids were diphosphatidylglycerol and phosphatidylglycerol. The major fatty acids were anteiso-C 15: 0, anteiso-C 17: 0 and iso-C 16: 0. The DNA G+C content of strain EGI 6500707 T was 69.1 mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain EGI 6500707 T should be placed in the genus Frigoribacterium (family Microbacteriaceae, phylum Actinobacteria), and that the novel strain exhibited the highest 16S rRNA gene sequence similarity to Frigoribacterium faeni JCM 11265 T (99.1%) and Frigoribacterium mesophilum MSL- 08 T (96.5%). DNA–DNA relatedness between strain EGI 6500707 T and F. faeni JCM 11265 T was 47.2%. On the basis of phenotypic and chemotaxonomic characteristics, phylogenetic analysis and DNA–DNA relatedness data, strain EGI 6500707 T represents a novel species of the genus Frigoribacterium, for which the name Frigoribacterium endophyticum sp. nov. is proposed. The type strain is EGI 6500707 T (=JCM 30093 T =KCTC 29493 T).