Pseudoxanthomonas gei sp. nov., a novel endophytic bacterium isolated from the stem of Geum aleppicum

Abstract

A Gram stain-negative, strictly aerobic, rod-shaped, non-motile and deep-yellow-coloured bacterial strain, designated ZFJR-3(T), was isolated from the stem of Geum aleppicum Jacq. collected from Taibai Mountain in Shaanxi Province, north-west China, and characterized by using a polyphasic approach. The novel isolate grew optimally at 25-28 °C and in the absence of NaCl. Flexirubin-type pigments were produced. The predominant respiratory quinone was ubiquinone-8 (Q-8) and the major cellular fatty acids were iso-C15:0 (29.2 %), iso-C16:0 (18.5 %), summed feature 9 (comprising iso-C17:1 ω9c and/or C16:0 10-methyl; 8.8 %), C16:1 ω7c alcohol (8.8 %), iso-C11:0 3-OH (6.9 %) and iso-C11:0 (6.8 %). The DNA G+C content was 66.1 mol %. The only polyamine was spermidine and the major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain ZFJR-3(T) belongs to the genus Pseudoxanthomonas and was most closely related to Pseudoxanthomonas yeongjuensis KCTC 22757(T) (16S rRNA gene sequence similarity, 99.0 %) and Pseudoxanthomonas sacheonensis KCTC 22080(T) (98.0 %). The levels of 16S rRNA gene sequence similarity with respect to other Pseudoxanthomonas species with validly published names were less than 96.5 %. DNA-DNA relatedness values for strain ZFJR-3(T) with respect to its closely related neighbours P. yeongjuensis KCTC 22757(T) and P. sacheonensis KCTC 22080(T) were 48.7 and 36.3 %, respectively. Based on the phenotypic, phylogenetic and genotypic data, strain ZFJR-3(T) is considered to represent a novel species of the genus Pseudoxanthomonas, for which the name Pseudoxanthomonas gei sp. nov. is proposed. The type strain is ZFJR-3(T) (=CCTCC AB 2013020(T) =KCTC 32298(T)).