Spirosoma telluris sp. nov. and Spirosoma arboris sp. nov. isolated from soil and tree bark, respectively

Two novel strains (HMF3257(T) and HMF4905(T)), isolated from freshwater and bark samples, were investigated to determine their relationships within and between species of the genus Spirosoma by using a polyphasic approach. They were aerobic, Gram-stain-negative, non-motile and rod-shaped bacteria. The major fatty acids (>10%) in both strains were identified as summed feature 3 (C-16:1 omega 7c and/or C-16:1 omega 6c) and C-16:1 omega 5c, while strains HMF3257(T) and HMF4905(T) contained a moderately high amount of C-16:0 and iso-C-15:0, respectively. The predominant respiratory quinone was MK-7 for both strains. In addition to phosphatidylethanolamine and one unidentified glycolipid, the polar lipid profile of strain HMF3257(T) consisted of three unidentified aminophospholipids, one unidentified aminolipid and two unidentified polar lipids, and that of strain HMF4905(T) consisted of one unidentified aminophospholipid, two unidentified aminolipids and three unidentified polar lipids. The DNA G+C contents of strains HMF3257(T) and HMF4905(T) were 47.2 and 46.4 mol%, respectively. Phylogenetic analysis based on 16S rRNA gene sequences showed that strains HMF3257(T) and HMF4905(T) are closely related to Spirosoma migulaei 15J9-8(T) (97.0% sequence similarity), while sharing 97.4% sequence similarity with each other. The average nucleotide identity value between strains HMF3257(T) and HMF4905(T) was 81.1%, and the digital DNA-DNA hybridization value between these two strains was 24.4 %. Based on the above data, strains HMF3257(T) and HMF4905(T) represent two novel members within the genus Spirosoma, for which the names Spirosoma telluris sp. nov. and Spirosoma arboris sp. nov. are proposed, respectively. The type strain of S. telluris is HMF3257(T) (=KCTC 62463(T)=NBRC 112670(T)) and type strain of S. arboris is HMF4905(T) (=KCTC 72779(T)=NBRC 114270(T)).