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Genome-based taxonomy of genera Haloarcula and Halomicroarcula, and description of six novel species of Haloarcula.

Authors :
Ma, Xue
Hu, Yao
Li, Xin-Xin
Tan, Shun
Cheng, Mu
Hou, Jing
Cui, Heng-Lin
Source :
Extremophiles. Apr2024, Vol. 28 Issue 1, p1-14. 14p.
Publication Year :
2024

Abstract

The genera Haloarcula and Halomicroarcula are the most closely related genera within the family Haloarculaceae (class Halobacteria). The respective 16S rRNA genes of type strains from the genus Haloarcula showed 94.7–96.5% similarities to their homologous genes of type strains from the genus Halomicroarcula. The Haloarcula species showed 89.3–92.8% rpoB′ gene similarities to Halomicroarcula species. These similarities were higher than the proposed genus boundary. Phylogenomic analysis revealed that these two genera formed a tight cluster separated from Halomicrobium with high bootstrap confidence. The average amino acid identity (AAI) values among Haloarcula and Halomicroarcula were 70.1–74.5%, higher than the cutoff value (67.0%) to differentiate the genera Haloarcula and Halomicroarcula from Halomicrobium. These results indicated that the genus Halomicroarcula should be merged with Haloarcula. Then, six novel species are described based on strains DFY41T, GDY20T, SHR3T, XH51T, YJ-61-ST, and ZS-22-S1T isolated from coarse sea salt, marine solar saltern, and salt lake (China). These six strains formed separate clades (90.1–99.3% 16S rRNA and 89.0–94.9% rpoB′ gene similarities) and then clustered with current Haloarcula and Halomicroarcula species (89.4–99.1% 16S rRNA and 87.6–95.0% rpoB′ gene similarities), as revealed by phylogenetic analyses. The average nucleotide identity (ANI), digital DNA-DNA hybridization (dDDH), and AAI values among these six strains and current Haloarcula and Halomicroarcula species were 76.2–89.8%, 25.3–46.0%, and 70.3–89.7%, respectively, clearly below the species demarcation threshold. These six strains were distinguished from current Haloarcula and Halomicroarcula species according to differential phenotypic characteristics. Six novel species, Haloarculahalophila sp. nov., Haloarculalitorea sp. nov., Haloarcularara sp. nov., Haloarculahalobia sp. nov., Haloarculapelagica sp. nov., and Haloarculaordinaria sp. nov., are proposed to accommodate strains DFY41T, GDY20T, SHR3T, XH51T, YJ-61-ST, and ZS-22-S1T, respectively. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
14310651
Volume :
28
Issue :
1
Database :
Academic Search Index
Journal :
Extremophiles
Publication Type :
Academic Journal
Accession number :
174811571
Full Text :
https://doi.org/10.1007/s00792-023-01329-9