Rubellimicrobium rubrum sp. nov., a novel bright reddish bacterium isolated from a lichen sample

A novel strain, YIM 131921^T, was isolated from a Physcia sp. lichen collected from the South Bank Forest of the Baltic Sea. The strain is Gram-negative, catalase positive and oxidase negative, strictly aerobic, asporogenous, non-motile and reddish brown in colour. The temperature and pH for growth were found to be 20-30 °C (optimum 28 °C) and pH 6.5-12.0 (optimum pH 7.0 ± 0.5). No growth was observed in the presence of NaCl. Based on 16S rRNA gene sequence similarity, strain YIM 131921^T shares high similarities with Rubellimicrobium roseum YIM 48858^T (98.3%), followed by Rubellimicrobium mesophilum MSL-20^T (96.8%), Rubellimicrobium aerolatum 5715S-9^T (96.1%) and Rubellimicrobium thermophilum DSM 16684^T (96.0%). Phylogenetic trees showed YIM 131921^T forms a cluster with type strains of the genus Rubellimicrobium. The predominant cellular fatty acids (> 20%) were identified as summed feature 8 (C_18:1ω7c) and C_16:0. Q-10 was found to be the predominant respiratory ubiquinone. The polar lipids were identified as diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, glycolipid, phospholipids and an unidentified aminolipid. The DNA G + C content of the draft genome sequence is 66.6 mol%. Strain YIM 131921^T showed an average nucleotide identity value of 80.3% and a digital DNA-DNA hybridizations value of 26.1% with the reference strain R. roseum YIM 48858^T based on draft genome sequences. Based on comparative analyses of phenotypic, molecular, chemotaxonomic data and genomic comparisons, strain YIM 131921^T is concluded to represent a novel species of the genus Rubellimicrobium, for which the name Rubellimicrobium rubrum sp. nov. is proposed. The type strain is YIM 131921^T (= CGMCC 1.13958^T = NBRC 114054^T = KCTC 72461^T).