Natronomonas salsuginis sp. nov., a New Inhabitant of a Marine Solar Saltern

Abstract

A halophilic archaeon, strain F20-122T, was isolated from a marine saltern of Isla Bacuta (Huelva, Spain). Cells were Gram-stain-negative, aerobic, and coccoid in morphology. It grew at 25–50 °C (optimum 37 °C), pH 6.5–9.0 (optimum pH 8.0), and 10–30% (w/v) total salts (optimum 25% salts). The phylogenetic analyses based on the 16S rRNA and rpoB’ genes showed its affiliation with the genus Natronomonas and suggested its placement as a new species within this genus. The in silico DNA–DNA hybridization (DDH) and average nucleotide identity (ANI) analyses of this strain against closely related species supported its placement in a new taxon. The DNA G + C content of this isolate was 63.0 mol%. The polar lipids of strain F20-122T were phosphatidylglycerol phosphate methyl ester (PGP-Me), phosphatidylglycerol (PG), and phosphatidylglycerol sulfate (PGS). Traces of biphosphatidylglycerol (BPG) and other minor phospholipids and unidentified glycolipids were also present. Based on the phylogenetic, genomic, phenotypic, and chemotaxonomic characterization, we propose strain F20-122T (= CCM 8891T = CECT 9564T = JCM 33320T) as the type strain of a new species within the genus Natronomonas, with the name Natronomonas salsuginis sp. nov. Rhodopsin-like sequence analysis of strain F20-122T revealed the presence of haloarchaeal proton pumps, suggesting a light-mediated ATP synthesis for this strain and a maximum wavelength absorption in the green spectrum.

Genomic Insights Into New Species of the Genus Halomicroarcula Reveals Potential for New Osmoadaptative Strategies in Halophilic Archaea

“…The presence of rhodopsin like-sequences in most Halomicroarcula genomes suggest a versatile metabolic flexibility in illuminated conditions for members of this genus. These results are in accordance with recent comparative genomic studies in other haloarchaeal genera ( Durán-Viseras et al, 2019a , 2020 , 2021 ) in which rhodopsins were also identified, and also with previous metagenomic analyses on hypersaline systems ( Fernández et al, 2014 ; Vera-Gargallo and Ventosa, 2018 ) that showed the existence of a large number of rhodopsin coding genes, clearly indicating the wide use of light by haloarchaea in these extreme habitats.…”

“…Phenotypic features of strains F24A T , F28, F27 T , and F13 T were performed according to the minimal standards established for the taxonomic description of novel taxa of the class Halobacteria ( Oren et al, 1997 ) and following the methodology previously described by Durán-Viseras et al, 2020 . Halomicroarcula pellucida CECT 7537 T , Halomicroarcula salina JCM 18369 T and Halomicroarcula limicola JCM 18640 T were used as reference strains for taxonomic comparisons.…”

A Differential Metabarcoding Approach to Describe Taxonomy Profiles of Bacteria and Archaea in the Saltern of Margherita di Savoia (Italy)

“…Natronomonas is a halophilic genus, deeply studied for possible biotechnological applications, for which only four species have been described so far [60]. The high abundance of this genus in waters of the saltern of MdS with low salinity (13.1%) differs from the optimal growth conditions currently reported (including salt concentrations around 25%) and leads to the hypothesis of the presence of new species.…”

Natronomonas halophila sp. nov. and Natronomonas salina sp. nov., two novel halophilic archaea

“…The genus Natronomonas (belonging to family Haloarculaceae , order Halobacteriales , class Halobacteria ) was established in 1997 and currently contains three validly published species: Natronomonas pharaonis [4], Natronomonas moolapensis [5] and Natronomonas gomsonensis [6], and a effectively published species, ‘ Natronomonas salsuginis ’ [7]. N.…”

“…The genus Natronomonas (belonging to family Haloarculaceae, order Halobacteriales, class Halobacteria) was established in 1997 and currently contains three validly published species: Natronomonas pharaonis [4], Natronomonas moolapensis [5] and Natronomonas gomsonensis [6], and a effectively published species, 'Natronomonas salsuginis' [7]. N. pharaonis is the type species of the genus, an extremely haloalkaliphilic archaeon that was isolated from alkaline salt-saturated brine samples of eutrophic desert lakes in Wadi Natrun, Egypt [8].…”