Solirubrobacter taibaiensis sp. nov., isolated from a stem of Phytolacca acinosa Roxb.

Abstract

A white-coloured bacterium, designated strain GTJR-20(T), was isolated from a stem of Phytolacca acinosa Roxb. collected from Taibai Mountain in Shaanxi Province, north-west China, and was subjected to a taxonomic study by using a polyphasic approach. The novel isolate was found to grow optimally at 28-30°C, at pH 7.5-8.0 and in the absence of NaCl. Cells were observed to be Gram-stain positive, strictly aerobic, rod-shaped and non-motile. The predominant respiratory quinone was identified as MK-7(H4) and the major cellular fatty acids were identified as iso-C16:0 (35.8%), C18:1 ω9c (17.7%), C17:1 ω6c (11.0%), C17:1 ω8c (7.8%) and C18:3 ω6c (6, 9, 12) (7.2%). The DNA G+C content was determined to be 71.6mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain GTJR-20(T) is a member of the genus Solirubrobacter and is closely related to Solirubrobacter phytolaccae GTGR-8(T) (16S rRNA gene sequence similarity, 98.4%), Solirubrobacter soli KCTC 12628(T) (97.8%), Solirubrobacter pauli KCTC 9974(T) (97.7%) and Solirubrobacter ginsenosidimutans KCTC 19420(T) (97.6%). No other recognized bacterial species showed more than 94.6% 16S rRNA gene sequence similarity to the novel isolate. DNA-DNA relatedness values for strain GTJR-20(T) with respect to its closely related neighbours S. phytolaccae GTGR-8(T), S. soli KCTC 12628(T), S. pauli KCTC 9974(T) and S. ginsenosidimutans KCTC 19420(T) were 48.3±8.6, 21.3±5.2, 36.8±6.2 and 36.0±5.5%, respectively. Based on the phenotypic, phylogenetic and genotypic data, strain GTJR-20(T) is considered to represent a novel species of the genus Solirubrobacter, for which the name Solirubrobacter taibaiensis sp. nov. is proposed. The type strain is GTJR-20(T) (=CCTCC AB 2013308(T)=KCTC 29222(T)).