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 ω 7 c and/or C 16 : 1 ω 6 c ) and C 16 : 1 ω 5 c , 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 ).