Description of Halosolutus amylolyticus gen. nov., sp. nov., Halosolutus halophilus sp. nov. and Halosolutus gelatinilyticus sp. nov., and genome-based taxonomy of genera Natribaculum and Halovarius

Int J Syst Evol Microbiol. 2022 Oct;72(10). doi: 10.1099/ijsem.0.005598.

Abstract

Three extremely halophilic archaeal strains (LT55T, SQT-29-1T and WLHS5T) were isolated from Gobi saline soil and a salt lake, China. These strains were most related to the genera Natribaculum and Halovarius (92.6-95.1 % similarities), and showed low similarities with other genera within the family Natrialbaceae based on 16S rRNA genes. Phylogenomic analysis confirmed that the three strains formed a distinct clade separated from the related genera Halostagnicola and Natronococcus, which indicated that they may represent a novel genus of the family Natrialbaceae. The average nucleotide identity (ANI), in silico DNA-DNA hybridization (isDDH) and average amino acid identity (AAI) values among the three strains were no more than 87, 34 and 85 %, respectively, much lower than the threshold values for species demarcation. The major phospholipids of the three strains were phosphatidic acid (PA), phosphatidylglycerol (PG) and phosphatidylglycerol phosphate methyl ester (PGP-Me). The glycolipid profiles of the three strains were diverse; sulfated mannosyl glucosyl diether (S-DGD-1) and disulfated mannosyl glucosyl diether (S2-DGD) were found in strains LT55T and WLHS5T, while mannosyl glucosyl diether (DGD-1) and S-DGD-1 in strain SQT-29-1T. The combination of phenotypic, chemotaxonomic, phylogenetic and genomic analyses suggested that strains WLHS5T (=CGMCC 1.13781T = JCM 33558T), SQT-29-1T (=CGMCC 1.16065T = JCM 33554T) and LT55T (=CGMCC 1.15188T = JCM 30838T) represent three novel species of a new genus within the family Natrialbaceae, for which the names, Halosolutus amylolyticus gen. nov., sp. nov., Halosolutus gelatinilyticus sp. nov. and Halosolutus halophilus sp. nov., are proposed. Genome-based classification of genera Natribaculum and Halovarius revealed that Halovarius luteus should be transferred to the genus Natribaculum as Natribaculum luteum comb. nov. and Natribaculum longum as a heterotypic synonym of Natribaculum breve Liu et al. 2015.

Keywords: Halosolutus; Halovarius; Natrialbaceae; Natribaculum; saline soil; salt lake.

MeSH terms

  • Amino Acids
  • Bacterial Typing Techniques
  • Base Composition
  • DNA, Archaeal / genetics
  • DNA, Bacterial / genetics
  • Esters
  • Fatty Acids* / chemistry
  • Glycolipids / chemistry
  • Halobacteriaceae*
  • Nucleotides
  • Phosphatidic Acids
  • Phosphatidylglycerols
  • Phylogeny
  • RNA, Ribosomal, 16S / genetics
  • Sequence Analysis, DNA
  • Soil

Substances

  • RNA, Ribosomal, 16S
  • DNA, Archaeal
  • Fatty Acids
  • DNA, Bacterial
  • Glycolipids
  • Phosphatidylglycerols
  • Soil
  • Nucleotides
  • Amino Acids
  • Phosphatidic Acids
  • Esters