Huang Zhaobin, Liu Renju, Chen Fenghua, Lai Qiliang, Oren Aharon, Shao Zongze
College of Oceanology and Food Science, Quanzhou Normal University, Quanzhou, China.
Key Laboratory of Inshore Resources Biotechnology (Quanzhou Normal University), Fujian Province University, Quanzhou, China.
Front Microbiol. 2021 Oct 20;12:755908. doi: 10.3389/fmicb.2021.755908. eCollection 2021.
Members of the family within the order are found to play vital roles in terrestrial and aquatic ecosystems by participating in biofloc formation in activated sludge, polycyclic aromatic hydrocarbon degradation, and nitrogen metabolism, such as denitrification and nitrogen fixation. Here, two bacterial strains designated H1-1-2A and ZN11-R3-1 affiliated to the family were isolated from coastal wetland habitats. The 16S rRNA gene sequences of the two strains were 100% identical and had maximum similarity with M9-3-2 of 98.4% and ≤94.5% with other species. Phylogenetic analysis suggested that the two strains belonged to a single species and formed a novel monophyletic branch affiliated to the genus . The average nucleotide identity (ANI) value and digital DNA-DNA hybridization (dDDH) estimate between the two strains and M9-3-2 were 78.5-78.7% and 21.4-21.6%, respectively, indicating that the two strains represent a novel species. The genomes of strain H1-1-2A (complete genome) and ZN11-R3-1 (draft genome) were 4.7Mbp in length encoding ~4,360 functional genes. The DNA G+C content was 62.7%. Nitrogen fixation genes were found in the two strains, which were responsible for the growth on nitrogen-free medium, whereas denitrification genes found in M9-3-2 were absent in the two strains. The respiratory quinone was ubiquinone-8. The major polar lipids consisted of phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, and aminophospholipid. The major fatty acids were summed feature 3 (C 7 and C 6), C, C, and C 3-OH. Based on genomic, phenotypic, and chemotaxonomic characterizations, strains H1-1-2A and ZN11-R3-1 represent a novel species of the genus , for which the name sp. nov. is proposed. The type strain is H1-1-2A (=MCCC 1K04284=KCTC 82672), and additional strain is ZN11-R3-1 (=MCCC 1A17971=KCTC 82671). Additionally, phylogenomic analysis of the members of the family including type strains and uncultivated bacteria was performed, using the Genome Taxonomic Database toolkit (GTDB-Tk). Combined with the 16S rRNA gene phylogeny, four novel genera, gen. nov., gen. nov., gen. nov., and gen. nov., were proposed. This study provided new insights to the taxonomy of the family .
该目下的该科成员通过参与活性污泥中的生物絮体形成、多环芳烃降解以及氮代谢（如反硝化作用和固氮作用），在陆地和水生生态系统中发挥着至关重要的作用。在此，从沿海湿地栖息地分离出了两株隶属于该科的细菌菌株，分别命名为H1-1-2A和ZN11-R3-1。这两株菌株的16S rRNA基因序列完全相同，与[具体属名]的M9-3-2相似度最高，为98.4%，与其他物种的相似度≤94.5%。系统发育分析表明，这两株菌株属于同一物种，并形成了一个隶属于[具体属名]的新单系分支。这两株菌株与M9-3-2之间的平均核苷酸同一性（ANI）值和数字DNA-DNA杂交（dDDH）估计值分别为78.5 - 78.7%和21.4 - 21.6%，表明这两株菌株代表一个新物种。菌株H1-1-2A（完整基因组）和ZN11-R3-1（草图基因组）的基因组长度为4.7Mbp，编码约4360个功能基因。DNA G+C含量为62.7%。在这两株菌株中发现了固氮基因，这使得它们能够在无氮培养基上生长，而在M9-3-2中发现的反硝化基因在这两株菌株中不存在。呼吸醌为泛醌-8。主要极性脂类由磷脂酰乙醇胺、二磷脂酰甘油、磷脂酰甘油和氨基磷脂组成。主要脂肪酸为总和特征3（C17:1ω6c和C16:1ω7c）、C16:0、C18:1ω7c和C18:1ω9c 3-OH。基于基因组、表型和化学分类学特征，菌株H1-1-2A和ZN11-R3-1代表[具体属名]的一个新物种，为此提出新物种名称[具体种名] sp. nov.。模式菌株为H1-1-2A（=MCCC 1K04284=KCTC 82672），另一菌株为ZN11-R3-1（=MCCC 1A17971=KCTC 82671）。此外，使用基因组分类数据库工具包（GTDB-Tk）对包括模式菌株和未培养细菌在内的该科成员进行了系统基因组分析。结合16S rRNA基因系统发育，提出了四个新属，分别为[新属名1] gen. nov.、[新属名2] gen. nov.、[新属名3] gen. nov.和[新属名4] gen. nov.。本研究为该科的分类学提供了新的见解。
