Mucilaginibacter corticis sp. nov., isolated from bark of Pinus koraiensis.

Abstract

A gram-stain negative, aerobic, non-motile and rod-shaped novel bacterial strain, designated MAH-19T, was isolated from bark of Pinus koraiensis. The colonies were observed to be light pink coloured, smooth, circular and 0.3-0.7mm in diameter when grown on R2A agar for 2days. Strain MAH-19T was found to be able to grow at 10-35°C (optimum 28-30°C), at pH 6.0-8.0 (optimum 7.0) and at 0-0.5% NaCl (optimum 0%). Cell growth occurs on nutrient agar and R2A agar. The strain was found to be positive for both catalase and oxidase tests. Cells are able to hydrolyse aesculin and Tween 20, but not casein, gelatin, starch, L-tyrosine, DNA, L-arginine, urea or Tween 80. According to the 16S rRNA gene sequence comparisons, the isolate was identified as a member of the genus Mucilaginibacter and to be closely related to Mucilaginibacter panaciglaebae BXN5-31T (97.4% similarity), Mucilaginibacter antarcticus S14-88T (97.2%) and Mucilaginibacter ximonensis XM-003T (97.1%). In DNA-DNA hybridization tests, the DNA relatedness between strain MAH-19T and its close phylogenetic neighbours was below 45.0%. The novel strain MAH-19T has a draft genome size of 5,335,442bp (14 contigs), annotated with 4963 protein-coding genes, 44 tRNA and 6 rRNA genes. The genomic DNA G+C content was determined to be 42.7mol%. The predominant isoprenoid quinone of strain MAH-19T was identified as MK-7. The major fatty acids were identified as C15:0 iso and summed feature 3 (comprising C16:1ω7c and/or C16:1ω6c). The DNA-DNA hybridization results and results of the genotypic analysis, in combination with chemotaxonomic and physiological data, demonstrated that strain MAH-19T represents a novel species within the genus Mucilaginibacter, for which the name Mucilaginibacter corticis sp. nov. is proposed, with MAH-19T (= KACC 19745T = CGMCC1.13657T) as the type strain.