Sphingobacterium cladoniae sp nov., isolated from lichen, Cladonia sp., and emended description of Sphingobacterium siyangense

A strictly aerobic, Gram-stain-negative bacterium, designated strain No.6(T), was isolated from a lichen (Cladonia sp.) collected in Geogeum Island, Korea, and its taxonomic status was established by a polyphasic study. Cells of strain No.6(T) were non-motile, catalase- and oxidase-positive, non-spore-forming rods. Growth was observed at 15-35 degrees C (optimum, 25-30 degrees C), at pH 5.0-10.0 (optimum, pH 6.0-8.0) and with 0-3% NaCl (optimum, 0-2%). The predominant cellular fatty acids were summed feature 3 (comprising iso-C-15:0 2-OH and/or C-16:1 omega 7c, 41.5%), iso-C-15:0 (26.7%) and C-16:0 (9.6 %), and menaquinone MK-7 was the only respiratory quinone. The G+C content of the genomic DNA of strain No.6(T) was 36.8 mol%. A phylogenetic tree based on 16S rRNA gene sequences showed that strain No.6(T) fell within the evolutionary group encompassed by the genus Sphingobacterium. Levels of 16S rRNA gene sequence similarity between the novel strain and the type strains of recognized Sphingobacterium species ranged from 92.1 to 99.1%, the highest values being with Sphingobacterium siyangense SY1(T) (99.1%) and Sphingobacterium multivorum IAM 14316(T) (98.5 %). DNA-DNA relatedness between strain No.6(T) and these two type strains were 32.0 and 5.7%, respectively. The polar lipids found in strain No.6(T) were phosphatidylethanolamine, two unidentified phospholipids, three unidentified aminophospholipids, one glycolipid and four unidentified lipids. One unidentified sphingolipid was also found. On the basis of phenotypic and genotypic data, strain No.6(T) represents a novel species of the genus Sphingobacterium, for which the name Sphingobacterium cladoniae sp. nov. is proposed. The type strain is No.6(T) (=KCTC 22613(T)=JCM 16113(T)). An emended description of Sphingobacterium siyangense is also proposed.