Institute of Jeju Microbial Resources, BioPS Co., Ltd., Jeju 63243, Republic of Korea.
Department of Biological Sciences and Biotechnology, Hannam University, Daejon 34054, Republic of Korea.
Int J Syst Evol Microbiol. 2024 Jul;74(7). doi: 10.1099/ijsem.0.006443.
Three actinobacterial strains, KSW2-21, KSW2-29 and KSW4-17, were isolated from dried seaweeds collected around Gwakji Beach in Jeju, Republic of Korea. Their taxonomic positions were determined based on genomic, physiological and morphological characteristics. The isolates were Gram-positive, aerobic, non-motile, rod-shaped bacteria characterized by the following chemotaxonomic features: ornithine as the cell wall diamino acid, the -glycolyl type of murein, MK-11 as the predominant menaquinone, polar lipids including diphosphatidylglycerol, phosphatidylglycerol, two unidentified glycolipids and four unidentified phospholipids, with anteiso-C, iso-C and anteiso-C as the the major fatty acids. The 16S rRNA gene phylogeny showed that the novel strains formed three distinct sublines within the genus . Strain KSW4-17 formed a tight cluster with the type strain of , while strains KSW2-21 and KSW2-29 occupied distinct positions between the type strains of and . Strains KSW4-17 and KSW2-29 showed 99.9 % rRNA gene sequence similarity to CGMCC 1.12512, while strain KSW2-21 revealed 99.4 % 16S rRNA gene sequence similarity to the type strains of and . The genome sizes and genomic G+C contents of the three isolates ranged from 3.44 to 3.74 Mbp and from 70.3 to 70.8 mol%, respectively. The phylogenomic tree based on 92 core gene sequences exhibited similar topologies to the 16S rRNA gene phylogeny. The comparison of overall genomic relatedness indices, such as average nucleotide indentity and digital DNA-DNA hybridization, supported that the isolates represent three new species of the genus . Based on the results obtained here, sp. nov. (type strain, KSW2-21=KACC 23322=DSM 116381), sp. nov. (type strain KSW2-29=KACC 22350=NBRC 115221) and sp. nov. (type strain, KSW4-17=KACC 23323=DSM 116383) are proposed.
三株放线菌，KSW2-21、KSW2-29 和 KSW4-17，从韩国济州岛歌志内海滩采集的干海藻中分离得到。它们的分类地位是根据基因组、生理和形态特征确定的。这些分离物是革兰氏阳性、需氧、非运动、棒状细菌，其化学分类特征如下：鸟氨酸为细胞壁二氨基庚二酸，甘氨酸型细胞壁，MK-11 为主要的甲萘醌，极性脂包括双磷脂酰甘油、磷脂酰甘油、两种未鉴定的糖脂和四种未鉴定的磷脂，主要脂肪酸为 anteiso-C、iso-C 和 anteiso-C。16S rRNA 基因系统发育表明，新菌株在属内形成三个不同的亚系。菌株 KSW4-17 与模式菌株形成紧密聚类，而菌株 KSW2-21 和 KSW2-29 则占据模式菌株 和 之间的不同位置。菌株 KSW4-17 和 KSW2-29 与 CGMCC 1.12512 的 16S rRNA 基因序列相似度为 99.9%，而菌株 KSW2-21 与 和 模式菌株的 16S rRNA 基因序列相似度为 99.4%。三个分离株的基因组大小和基因组 G+C 含量分别为 3.44-3.74 Mbp 和 70.3-70.8mol%。基于 92 个核心基因序列的系统基因组树显示出与 16S rRNA 基因系统发育树相似的拓扑结构。整体基因组相关性指数（如平均核苷酸同一性和数字 DNA-DNA 杂交）的比较支持这些分离物代表属的三个新种。基于这里获得的结果，提议命名新种. sp. nov.（模式菌株，KSW2-21=KACC 23322=DSM 116381）、. sp. nov.（模式菌株 KSW2-29=KACC 22350=NBRC 115221）和. sp. nov.（模式菌株，KSW4-17=KACC 23323=DSM 116383）。
