Sphingomonas populi sp. nov., isolated from bark of Populus × euramericana

One Gram-stain-negative, aerobic, motile bacterial strain, 3-7 T , was isolated from symptomatic canker bark tissue of Populus × euramericana . 16S rRNA gene sequence data revealed that the novel isolate shared highest similarity with Sphingomonas panacis DCY99 T (98.8 %), and <96.5 % sequence similarity with all other species with validly published names. Growth occurred between 15 and 37 °C and at pH 6.0–9.0, and optimal growth occurred at 30 °C and pH 7.0–8.0. Nitrogen was produced from nitrates. The strain was positive for acetoin production and activity of catalase, oxidase, β -galactosidase, arginine dihydrolase and β -glucosidase. The major fatty acids were C 16 : 0 , C 18 : 1 ω7 c and/or C 18 : 1 ω6 c . The polar lipids of the novel isolate included diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, sphingoglycolipid, glycolipid, two uncharacterized phospholipids and two uncharacterized lipids. The respiratory quinones detected in isolate 3-7 T were Q-10 (96.9 %) and Q-9 (3.1 %). The DNA G+C content was 65.1 mol%. Based on phenotypic and genotypic characteristics, the isolate represents a novel species within the genus Sphingomonas , for which the name Sphingomonas populi is proposed. The type strain is 3-7 T (=CFCC 11561 T =LMG 30138 T ).