Leucobacter populi sp. nov. isolated from a symptomatic bark of Populus × euramericana canker.

A Gram-stain positive, aerobic, non-motile, rod-shaped, oxidase-negative and catalase-positive bacterial strain, designated 06C10-3-11T, was isolated from the symptomatic bark of a Populus × euramericana canker. Growth occurred at 10-45 °C (optimum, 30 °C), pH 6-11 (optimum, pH 7.0-8.0), 0-7 % (w/v) NaCl (optimum, 0-1 %) and in the presence of 20 mM Cr (VI). The major fatty acids (≥10 %) of the novel strain were identified as anteiso-C15:0, anteiso-C17:0 and iso-C16:0. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phospholipid, glycolipid and two unknown lipids. The strain contained the respiratory quinone MK-10 (71 %) as a major component and MK-11 (29 %) in lesser amounts. The cell wall amino acids were 2,4-diaminobutyric acid, alanine, glutamic acid and glycine. The genomic DNA G+C content of the type strain was 69.8 mol%. Phylogenetic analysis, based on 16S rRNA gene sequences, indicated that strain 06C10-3-11T belongs to the genus Leucobacter, showing the highest 16S rRNA gene sequence similarities with Leucobacter celer NAL101T (96.19 %), 'Leucobacter kyeonggiensis' F3-P9T (96.18 %), Leucobacter denitrificans M1T8B10T (96.10 %) and Leucobacter aridicollis CIP 108388T (96.06 %). The DNA G+C content of strain 06C10-3-11T was 69.8 mol%. Based on the molecular data and physiological and biochemical characteristics, strain 06C10-3-11T is considered to represent a novel species of the genus Leucobacter, for which the name Leucobacterpopuli sp. nov. is proposed. The type strain is 06C10-3-11T (= CFCC 12199T = KCTC 39685T).