Leucobacter corticis sp. nov., isolated from symptomatic bark of Populus × euramericana canker.

Abstract

A Gram-stain-positive, aerobic, non-motile, rod-shaped bacterial strain, designated 2C-7T, was isolated from symptomatic bark of a Populus × euramericana canker. Growth occurred between 10 and 37 °C and between pH 6 and 10, with optimal growth at 30 °C and pH 7.0-8.0. Growth was present under 0-8 % (w/v) salinity conditions (optimum 1-2 %). Growth occurred in the presence of 10 mM chromium (Cr6+). The major fatty acids (≥10 %) of the novel strain were anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phospholipid, glycolipid and two unknown lipids. The major respiratory quinone was menaquinone MK-11. The cell wall amino acids were 2,4-diaminobutyric acid, alanine, glutamic acid and glycine. Strain 2C-7T was most similar to Leucobacter celer subsp. celer NAL101T (97.2 % 16S rRNA gene sequence similarity), 'Leucobacter kyeonggiensis' F3-P9T (97.1 %) and Leucobacter chromiireducens L-1T (97.1 %). In the phylogenetic tree, the isolate formed a single distinct branch separate from those of L. celer subsp. celer NAL101T, 'L. kyeonggiensis' F3-P9T and Leucobacter chironomi DSM 19883T. The DNA-DNA hybridization values between the novel strain and the reference strains were lower than the accepted bacterial threshold level of 70 % for species delineation. The DNA G+C content of strain 2C-7T was 70.0 mol%. Based on the data, strain 2C-7T represents a novel species in the genus Leucobacter, for which the name Leucobacter corticis sp. nov. is proposed. The type strain is 2C-7T (=CFCC 11901T=KCTC 39643T).