Brachybacterium halotolerans sp. nov., a halotolerant, endophytic actinomycete isolated from branch of Bruguiera gymnoirhiza

• Published in: Antonie van Leeuwenhoek 2021-06, Vol.114 (6), p.875-884
• Main Authors: Chen, Ming-Sheng, Li, Fei-Na, Chen, Xiao-Hui, Yan, Xiao-Rui, Tuo, Li
• Format: Article
• Language: English
• Subjects: Actinobacteria - genetics; Bacterial Typing Techniques; Base Composition; Biomedical and Life Sciences; Bruguiera; Cardiolipin; China; Deoxyribonucleic acid; DNA; DNA, Bacterial - genetics; Endophytes; Fatty acids; Fatty Acids - analysis; Gene sequencing; Genomes; Hybridization; Life Sciences; Lipids; Medical Microbiology; Menaquinones; Microbiology; Nature reserves; New species; Nucleotide sequence; Nucleotides; Original Paper; Peptidoglycans; pH effects; Phosphatidylglycerol; Phospholipids - analysis; Phylogeny; Plant Sciences; Rhizophoraceae; RNA, Ribosomal, 16S - genetics; rRNA 16S; Salinity tolerance; Sequence Analysis, DNA; Sodium chloride; Soil Science & Conservation
• ISSN: 0003-6072; 1572-9699
• DOI: 10.1007/s10482-021-01565-z

A novel, aerobic, moderately halophilic Gram-positive actinomycete, strain MASK1Z-5 T was isolated from a surface-sterilized branch of Bruguiera gymnoirhiza in Shankou Mangrove Nature Reserve, Guangxi, China. The taxonomic position of the strain was investigated using a polyphasic approach. Strain MASK1Z-5 T tolerated up to 20% (w/v) NaCl (optimum 0–7%), and grew at pH 5.0–12.0 (optimum pH 7.0–8.0), 20–37 °C (optimum 30 °C). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain MASK1Z-5 T belonged to the genus Brachybacterium , and showed the highest 16S rRNA gene sequence similarity of 98.0% to B. endophyticum M1HQ-2 T . The cell-wall peptidoglycan contained meso -diaminopimelic acid as diagnostic diamino acid. MK-7 was the predominant menaquinone. The polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, one unidentified glycolipid and three unidentified lipids. The major fatty acids were anteiso -C 15:0 , iso -C 16:0 and anteiso -C 17:0 . The DNA G + C content was calculated to be 71.8 mol% based on the whole genome sequence. The estimated values of average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) based on whole genome sequences between strain MASK1Z-5 T and B. endophyticum M1HQ-2 T were 81.8% and 25.0%, respectively. The phenotypic, chemotaxonomic and genotypic properties clearly indicated that strain MASK1Z-5 T represents a novel species within the genus Brachybacterium , for which the name Brachybacterium halotolerans sp. nov. is proposed. The type strain is MASK1Z-5 T (= CGMCC1.18660 T  = JCM 34339 T ).