Sphingobacterium populi sp nov., isolated from bark of Populus x euramericana

A Gram-stain-negative, aerobic, non-motile bacterial strain, 7Y-4(T), was isolated from bark tissue of Populus x euramericana. The isolate was able to grow between 10 and 37 degrees C, with optimal growth occurring at 28-30 degrees C. Strain 7Y-4(T) was positive for oxidase and catalase activities, but did not reduce nitrite from nitrate. Positive reactions were observed for the activities of beta-galactosidase, urease and beta-glucosidase, but negative reactions for the activities of gelatinase and the production of indole, acetoin and H2S. Citrate was not utilized. The major fatty acids of strain 7Y-4(T) are iso-C-15:0 (28.6 %), C-16:1 omega 7c/C-16:1 omega 6c (31.8 %) and iso-C-17:0 3-OH (23.3 %). The major polar lipids of the novel isolate include phosphatidylethanolamine, three unknown phospholipids (PL1-3) and six unknown lipids (L1-6), and the predominant menaquinone is MK-7. The DNA G+C content is 41.7 mol%. Analysis of 16S rRNA gene sequences revealed that the novel isolate shared the greatest sequence similarity with Sphingobacterium hotanense XH4(T) (93.50 %). On the basis of phenotypic and genotypic characteristics, strain 7Y-4(T) represents a novel species of the genus Sphingobacterium, for which the name Sphingobacterium populi is proposed. The type strain is 7Y-4(T) (=CFCC 11742(T) =KCTC 42247(T)).