Microbacterium hibisci sp nov., isolated from rhizosphere of mugunghwa (Hibiscus syriacus L.)

A Gram-stain-positive, aerobic, non-motile, short-rod shaped actinobacterium, designated THG-T2.14(T), was isolated from soil sampled from the rhizosphere of mugunghwa. Growth occurred at 10-40 degrees C (optimum 30 degrees C), at pH 5.0-10.0 (optimum 7.0) and at 0-7.0% NaCl (optimum 3.0 %). Based on 16S rRNA gene sequence analysis, the nearest phylogenetic neighbours of strain THG-T2.14(T) were identified as Microbacterium yannicii DSM 23203(T) (98.8 %), Microbacterium trichothecenolyticum DSM 8608(T) (98.8 %), Microbacterium arthrosphaerae DSM 22421(T) (98.7 %) and Microbacterium jejuense KACC 17124(T) (98.4 %). The major fatty acids were anteiso-C-15:0, anteiso-C-17:0 and iso-C-16:0. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, one unidentified lipid, two unidentified phospholipids and two unidentified phosphoglycolipids. The menaquinones were MK-12, and MK-13. The major polyamine was spermidine. The peptidoglycan contained ornithine, alanine, glycine, homoserine and glutamic acid. The diagnostic diamino acid was ornithine. The acyl type of the muramic acid was glycolyl. The whole-cell sugars were rhamnose, ribose, galactose, arabinose, xylose and glucose. The DNA G+C content of strain THG-T2.14(T) was 71.2 mol%. The DNA-DNA relatedness between strain THG-T2.14(T) and its closest reference strains were significantly lower than the threshold value of 70 %. On the basis of the phylogenetic analysis, chemotaxonomic data, physiological characteristics and DNA-DNA hybridization data, strain THG-T2.14(T) represents a novel species of the genus Microbacterium, for which the name Microbacterium hibisci sp. nov. is proposed. The type strain is THG-T2.14(T) (= KACC 18931(T) = CCTCC AB 2016180(T)).