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

Abstract

A Gram-stain-positive, pink-pigmented, coccus-shaped, strictly aerobic, non-motile bacterium, strain THG-AG1.5T, was isolated from rhizosphere of Hibiscus syriacus L. (Mugunghwa flower) located in Kyung Hee University, Yongin, Gyeonggi, Republic of Korea. The isolated strain grew optimally at 25-30 °C, at pH 6.0-7.5 and in the presence of additional 0-1.5 % (w/v) NaCl. Strain THG-AG1.5T exhibited tolerance to UV radiation (>1500 J m-2) and to gamma radiation (>12 kGy). Based on 16S rRNA gene sequence comparisons, strain THG-AG1.5T was closely related to Deinococcus daejeonensis MJ27T (98.03 %), Deinococcus radiotolerans C1T (97.61 %) and Deinococcus grandis DSM 3963T (97.32 %). The genomic DNA G+C content of strain THG-AG1.5T was 74.8 mol%. The DNA-DNA hybridization values between strain THG-AG1.5T and its closest phylogenetically neighbours were below 63.0 %. The peptidoglycan amino acids were alanine, valine, glutamic acid, glycine, ornithine, lysine and aspartic acid. Strain THG-AG1.5T contained ribose, mannose and glucose as whole-cell-wall sugars and menaquinone-8 (MK-8) as the only isoprenoid quinone. The major component in the polyamine pattern was spermidine. The major polar lipids of strain THG-AG1.5T were a phosphoglycolipid, six unidentified glycolipids and an unidentified aminophospholipid. The major fatty acids were identified as iso-C15 : 0, C15 : 1ω6c, C16 : 0, iso-C17 : 0, C17 : 0, C18 : 0 and summed feature 3. On the basis of our polyphasic taxonomy study, strain THG-AG1.5T represents a novel species within the genus Deinococcus, for which the name Deinococcushibisci sp. nov. is proposed. The type strain is THG-AG1.5T (=KACC 18850T=CCTCC AB 2016078T).