Halomarina litorea sp. nov., Halomarina pelagica sp. nov., Halomarina halobia sp. nov., and Halomarina ordinaria sp. nov., Halophilic Archaea Isolated from Coastal and Inland Saline Soil.

Four halophilic archaeal strains, BCD28T, BND7T, PSR21T, and PSRA2T, were isolated from coastal and inland saline soil, respectively. The 16S rRNA and rpoB' gene sequence similarities among these four strains and current species of Halomarina were 95.9-96.6% and 86.9-90.3%, respectively. Phylogenetic and phylogenomic analyses revealed that these four strains tightly cluster with the current species of the genus Halomarina. The AAI, ANI, and dDDH values among these four strains and current species of Halomarina were 65.3-68.4%, 75.8-77.7%, and 20.3-22.0%, respectively, clearly below the threshold values for species demarcation. Strains BCD28T, BND7T, PSR21T, and PSRA2T could be differentiated from the current species of Halomarina based on the comparison of diverse phenotypic characteristics. The major polar lipids of these four strains were phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me), and four to five glycolipids. Phosphatidylglycerol sulfate (PGS) was only detected in strain BND7T. The phenotypic, phylogenetic, and genome-based analyses suggested that strains BCD28T (= CGMCC 1.18776T = JCM 34908T), BND7T (= CGMCC 1.18778T = JCM 34910T), PSR21T (= CGMCC 1.17027T = JCM 34147T), and PSRA2T (= CGMCC 1.17214T = JCM 34148T) represent four novel species of the genus Halomarina, for which the names Halomarina litorea sp. nov., Halomarina pelagica sp. nov., Halomarina halobia sp. nov., and Halomarina ordinaria sp. nov. are proposed.

Halobaculum rubrum sp. nov., an extremely halophilic archaeon isolated from a salt lake.

A halophilic archaeal strain, designated C46T, was isolated from an inland salt lake in Qinghai Province, PR China. Results of phylogenetic analysis based on 16S rRNA gene sequences indicated that strain C46T belongs to the genus Halobaculum, and the closest phylogenetic relative is Halobaculum gomorrense DSM 9297T with 97.7 % similarity. Despite this, strain C46T was more related to Halobaculum saliterrae WSA2T than other members of the genus Halobaculum based on genome comparison and analysis, and the average nucleotide identity, in silico DNA-DNA hybridization, amino acid identity and percentage of conserved protein values between the two strains were 89.1, 53.3, 89.2 and 75.6 %, respectively, which are lower than the cutoff values proposed for species delimitation. The physiological, biochemical, genetic and genomic characteristics of strain C46T were different from those of its closest phylogenetic neighbours, which indicated that this strain represents a novel species of the genus Halobaculum, for which the name Halobaculum rubrum sp. nov. is proposed. The type strain is C46T (=CGMCC 1.13737T=JCM 32959T).

Halobaculum halophilum sp. nov. and Halobaculum salinum sp. nov., isolated from salt lake and saline soil.

Two halophilic archaeal strains, Gai3-2T and NJ-3-1T, were isolated from salt lake and saline soil samples, respectively, collected in PR China. The 16S rRNA gene sequences of the two strains were 97.5% similar to each other. Strains Gai3-2T and NJ-3-1T had the highest sequence similarities to 'Halobonum tyrrellense' G22 (96.7 and 97.8%, respectively), and displayed similarities of 91.5-93.5% and 92.3-94.7%, respectively, to Halobaculum members. Phylogenetic analysis revealed that the two strains formed different branches and clustered tightly with 'H. tyrrellense' G22 and Halobaculum members. The average nucleotide identity (ANI), in silico DNA-DNA hybridization (isDDH) and amino acid identity (AAI) values between the two strains were 83.1, 26.9 and 77.9%, respectively, much lower than the threshold values proposed as a species boundary. These values between the two strains and 'H. tyrrellense' G22 (ANI 77.9-78.2%, isDDH 22.5-22.6% and AAI 68.8-69.3%) and Halobaculum members (ANI 77.53-77.63%, isDDH 21.8-22.3% and AAI 68.4-69.4%) were almost identical, and much lower than the recommended threshold values for species delimitation. These results suggested that strains Gai3-2T and NJ-3-1T represent two novel species of Halobaculum. Based on phenotypic, chemotaxonomic and phylogenetic properties, strains Gai3-2T (=CGMCC 1.16080T=JCM 33550T) and NJ-3-1T (=CGMCC 1.16040T=JCM 33552T) represent two novel species of the genus Halobaculum, for which the name Halobaculum halophilum sp. nov. and Halobaculum salinum sp. nov. are proposed.

Halosimplex halophilum sp. nov. and Halosimplex salinum sp. nov., isolated from saline soil and a salt mine.

A polyphasic study was undertaken to determine the taxonomic position of two halophilic archaeal strains, TH32T and YPL4T, isolated from saline soil and a salt mine in PR China, respectively. Strains TH32T and YPL4T both have two dissimilar 16S rRNA genes. The two strains exhibited sequence similarities of 91.5-95.5 % for 16S rRNA genes and 90.9 % for the rpoB' gene. Sequence similarities of 16S rRNA genes and the rpoB' gene between the two strains and the current four members of Halosimplex were 90.6-97.4 % and 91.4-93.5 %, respectively. Phylogenetic analysis revealed that the two strains formed different branches separating them from the current Halosimplex members. Several phenotypic characteristics differentiate strains TH32T and YPL4T from current Halosimplex members. The polar lipids of the two strains are phosphatidic acid, phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and four glycolipids. Two of the glycolipids are chromatographically identical to disulfated mannosyl glucosyl diether and sulfated mannosyl glucosyl diether, respectively, and the remaining two glycolipids are unidentified. The average nucleotide identity (ANI) and in silico DNA-DNA hybridization (DDH) values between the two strains and the current members of Halosimplex (ANI 80.4-89.2 % and in silico DDH 24.0-41.8 %) were much lower than the threshold values proposed as a species boundary, suggesting that the two strains represent novel species of Halosimplex. The values between the two strains (ANI 81.3 % and in silico DDH 24.9 %) were also much lower than the recommended threshold values, which revealed that the two strains represent two genomically different species of Halosimplex. These results showed that strains TH32T (=CGMCC 1.15190T=JCM 30840T) and YPL4T (=CGMCC 1.15329T=JCM 31108T) represent two novel species of Halosimplex, for which the names Halosimplex halophilum sp. nov. and Halosimplex salinum sp. nov. are proposed.

Natronorubrum halalkaliphilum sp. nov., a haloalkaliphilic archaeon isolated from soda lake in Inner Mongolia Autonomous Region, China.

A haloalkaliphilic strain JWXQ-INN-674T was isolated from the water sample of a soda lake in Inner Mongolia Autonomous Region, China. Cells of the strain were coccoid, motile, and strictly aerobic. The strain was able to grow in presence of 2.6-5.4 M NaCl (optimum concentration is 3.4 M) at 30-50 °C (optimum temperature is 42 °C) and pH 7-9.5 (optimum pH is 9.0). The 16S rRNA gene sequence of strain JWXQ-INN-674T showed 95.3-96.6% similarity to members of the genus Natronorubrum of the family Natrialbaceae. The whole genome sequencing of strain JWXQ-INN-674T revealed a genome size of 4.56 M bp and a DNA G + C content of 62.5 mol%. Genome relatedness of strain JWXQ-INN-674T and other species in the genus Natronorubrum was analyzed by average nucleotide identity and digital DNA-DNA hybridization with the values of 76.8-90.6 and 23.1-39.3%, respectively. The strain possessed the polar lipids phosphatidylglycerol and methylated phosphatidylglycerol phosphate lipid. No glycolipids were detected. Based on phylogenetic analysis, phenotypic characteristics, chemotaxonomic properties and genome relatedness, the isolate was proposed as the type strain of a novel species of genus Natronorubrum, Natronorubrum halalkaliphilum sp. nov. (type strain JWXQ-INN-674T = CGMCC 1.17283T = JCM 34245T).

Salinadaptatus halalkaliphilus gen. nov., sp. nov., a haloalkaliphilic archaeon isolated from salt pond in Inner Mongolia Autonomous Region, China.

A haloalkaliphilic strain XQ-INN 246T was isolated from the sediment of a salt pond in Inner Mongolia Autonomous Region, China. Cells of the strain were rods, motile and strictly aerobic. The strain was able to grow in the presence of 2.6-5.3 M NaCl (optimum concentration is 4.4 M) at 30-50 °C (optimum temperature is 42 °C) and pH 7.0-10.0 (optimum pH is 8.0-8.5). The whole genome sequencing of strain XQ-INN 246T revealed a genome size of 4.52 Mbp and a DNA G+C content of 62.06 mol%. Phylogenetic tree based on 16S rRNA gene sequences and concatenated amino acid sequences of 122 single-copy conserved proteins revealed a robust lineage of the strain XQ-INN 246T with members of related genera of the family Natrialbaceae. The strain possessed the polar lipids of phosphatidylglycerol and phosphatidylglycerol phosphate methyl ester. No glycolipids were detected. Based on phylogenetic analysis, phenotypic characteristics, chemotaxonomic properties and genome relatedness, the isolate was proposed as the type strain of a novel species of a new genus within the family Natrialbaceae, for which the name Salinadaptatus halalkaliphilus gen. nov., sp. nov. is proposed. The type strain is XQ-INN 246T (=CGMCC 1.16692T=JCM 33751T).

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

Two halophilic archaeal strains, C90T and YPL13T, were isolated from a salt lake and a salt mine in PR China. The two strains were found to form two clusters (97.5 and 89.5 % similarity between them, respectively) separating them from the three current members of the genus Natronomonas (95.4-97.0 % and 86.6-89.3 % similarity, respectively) on the basis of the 16S rRNA and rpoB' gene sequence similarities and phylogenetic analysis. Diverse phenotypic characteristics differentiate strains C90T and YPL13T from current Natronomonas members. The polar lipids of strain C90T were phosphatidic acid, phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me), phosphatidylglycerol sulphate, two unidentified glycolipids, a major glycolipid and a minor glycolipid, while those of strain YPL13T were PG, PGP-Me, two unidentified phospholipids and a glycolipid. The average nucleotide identity (ANI) and in silico DNA-DNA hybridization (isDDH) values between the two strains were 79.8 and 27.1 %, respectively, which were much lower than the threshold values proposed as a species boundaries (ANI 95-96 % and isDDH 70 %), which revealed that the two strains represent two novel species; these values (ANI 76.6-80.0 % and isDDH 21.6-27.0 %) of the strains examined in this study and the current members of Natronomonas are much lower than the recommended threshold values, suggesting that strains C90T and YPL13T represent two genomically different species of Natronomonas. These results showed that strains C90T (=CGMCC 1.13738T=JCM 32961T) and YPL13T (=CGMCC 1.13884T=JCM 31111T) represent two novel species of Natronomonas, for which the names Natronomonas halophila sp. nov. and Natronomonas salina sp. nov. are proposed.

Halobacterium bonnevillei sp. nov., Halobaculum saliterrae sp. nov. and Halovenus carboxidivorans sp. nov., three novel carbon monoxide-oxidizing Halobacteria from saline crusts and soils.

Three novel carbon monoxide-oxidizing Halobacteria were isolated from Bonneville Salt Flats (Utah, USA) salt crusts and nearby saline soils. Phylogenetic analysis of 16S rRNA gene sequences revealed that strains PCN9T, WSA2T and WSH3T belong to the genera Halobacterium, Halobaculum and Halovenus, respectively. Strains PCN9T, WSA2T and WSH3T grew optimally at 40 °C (PCN9T) or 50 °C (WSA2T, WSH3T). NaCl optima were 3 M (PCN9T, WSA2T) or 4 M NaCl (WSH3T). Carbon monoxide was oxidized by all isolates, each of which contained a molybdenum-dependent CO dehydrogenase. G+C contents for the three respective isolates were 66.75, 67.62, and 63.97 mol% as derived from genome analyses. The closest phylogenetic relatives for PCN9T, WSA2T and WSH3T were Halobacterium noricense A1T, Halobaculum roseum D90T and Halovenus aranensis EB27T with 98.71, 98.19 and 95.95 % 16S rRNA gene sequence similarities, respectively. Genome comparisons of PCN9T with Halobacterium noricense A1T yielded an average nucleotide identity (ANI) of 82.0% and a digital DNA-DNA hybridization (dDDH) value of 25.7 %; comparisons of WSA2T with Halobaculum roseum D90T yielded ANI and dDDH values of 86.34 and 31.1 %, respectively. The ANI value for a comparison of WSH3T with Halovenus aranensis EB27T was 75.2 %. Physiological, biochemical, genetic and genomic characteristics of PCN9T, WSA2T and WSH3T differentiated them from their closest phylogenetic neighbours and indicated that they represent novel species for which the names Halobaculum bonnevillei, Halobaculum saliterrae and Halovenus carboxidivorans are proposed, respectively. The type strains are PCN9T (=JCM 32472=LMG 31022=ATCC TSD-126), WSA2T (=JCM 32473=ATCC TSD-127) and WSH3T (=JCM 32474=ATCC TSD-128).

Halocatena pleomorpha gen. nov. sp. nov., an extremely halophilic archaeon of family Halobacteriaceae isolated from saltpan soil.

A novel archaeal strain designated as SPP-AMP-1T was isolated from saltpan soil, using the serial dilution method on a halophilic archaeal medium supplemented with ampicillin. Cells were both rod-shaped and pleomorphic in nature, non-motile, unable to produce acid from a variety of sugars or grow anaerobically with different substrates (l-arginine) and electron acceptors (DMSO, nitrate). Optimal growth was observed at 42 °C, 3.4-4.2 M NaCl and pH 7.2. Cells did not lyse in distilled water and grew in the absence of Mg2+ ions. Phylogenetic analysis based on the sequences of 16S rRNA gene, amino acid sequence of ß'-subunit of RNA polymerase and 400 conserved proteins retrieved from the whole genome assemblies showed that strain SPP-AMP-1T was distantly related to any existing genera within the family Halobacteriaceae. MK-8 was the only quinone detected. Polar lipid analysis showed a unique combination of diethyl derivatives of phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, glycosyl-mannosyl-glucosyl diether and sulphated glycosyl-mannosyl-glucosyl diether as the major lipids. The G+C content of genomic DNA is 57.7 mol%. The phenotypic, phylogenetic and genomic data supported the concept of the novel genus status of strain SPP-AMP-1T in the family Halobacteriaceae for which the name Halocatena pleomorpha gen. nov., sp. nov., is proposed; the type strain is SPP-AMP-1T (=JCM 31368T=KCTC 4276T=MTCC 12579T).

Haloplanus rubicundus sp. nov., an extremely halophilic archaeon isolated from solar salt.

Two extremely halophilic archaea strains, CBA1112T and CBA1113, were isolated from solar salt in Korea. The genome sizes and G+C content of CBA1112T and CBA1113 were 3.77 and 3.53Mb, and 66.0 and 66.5mol%, respectively. Phylogenetic analysis based on closely related taxa and environmental Haloplanus sequences indicated that both CBA1112T and CBA1113 strains are grouped within the genus Haloplanus. OrthoANI and in silico DNA-DNA hybridization values were below the species delineation threshold. Pan-genomic analysis showed that the two novel strains and four reference strains had 6203 pan-orthologous groups in total. Six Haloplanus strains shared 1728 core pan-genome orthologous groups, which were mainly associated with amino acid transport and metabolism and translation, ribosomal structure and biogenesis categories, and amino acid metabolism and carbohydrate metabolism related categories. The novel strain-specific pan-genome orthologous groups were mainly involved with replication, recombination and repair category and replication and repair pathway or amino acid metabolism pathway. Cells of both strains were Gram-negative and pleomorphic, and colonies were red-pigmented. The major polar lipids of both strains were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate, and one glycolipid, sulfated mannosyl glucosyl diether. Based on genomic, phylogenetic, phenotypic, and chemotaxonomic features, strains CBA1112T and CBA1113 are described as novel species of the genus Haloplanus. Thus, we propose the name Haloplanus rubicundus sp. nov. The type strain is CBA1112T (=KCCM 43224T=JCM 30475T).

Natrialba swarupiae sp. nov., a halophilic archaeon isolated from a hypersaline lake in India.

A haloarchaeal strain (ESP3B_9T) was isolated from the salt pan of Sambhar salt lake, Rajasthan, India. Cells were coccoid, non-motile, Gram-stain-negative and formed reddish-pink pigmented colonies. The strain was aerobic, able to grow at 35-55 °C (optimum, 40 °C), in 20-35 % (25 %) NaCl and pH 8-10 (pH 9). Mg2+ not required for growth. The cells were lysed in distilled water and the minimum NaCl concentration that prevented cell lysis was 5 % w/v. The 16S rRNA gene sequence similarities between strain ESP3B_9T and Natrialba hulunbeirensis JCM 10989T and Natrialba magadii ATCC 43099T were 96.53 and 96.25 % respectively. The similarities of the RNA polymerase subunit B gene between strain ESP3B_9T and N. hulunbeirensis JCM 10989T and N. magadii ATCC 43099T were 84.47 and 84.9 % respectively. Genome sequencing revealed a genome size of 4.20 Mbp with DNA G+C content of 62.5 mol%. The major polar lipids were phosphotidylglycerol and phosphatidylglycerol phosphate methyl esters with minor amounts of unidentified lipids. The results of polyphasic analysis determined that strain ESP3B_9T represents a novel species of the genus Natrialba, for which the name Natrialba swarupiae sp. nov. is proposed. The type strain is ESP3B_9T (MCC 3419T=JCM 33002T=KCTC 4279T=CGMCC 1.16737T).

Halostella pelagica sp. nov. and Halostella litorea sp. nov., isolated from salted brown alga Laminaria.

Three rod-shaped halophilic archaeal strains, DL-M4T, LYG-109 and DLLS-108T, were isolated from the salted brown alga Laminaria produced in different marine areas of PR China. Cells of strains were motile, formed red-pigmented colonies on agar and lysed in distilled water. The three strains grew optimally with 2.6 M NaCl, with 0.05-0.3 M MgCl2, at 37 °C and at pH 7.0-7.5. The results of phylogenetic analyses based on the 16S rRNA and rpoB' genes differentiated these strains into two clusters belonging to the genus Halostella, which currently contains Halostella salina CBA1114T and Halostella limicola LT12T. Strains DL-M4T and LYG-109 formed a single cluster separate from the current two members of Halostella (94.4-95.7 and 90.0-90.9 % similarities, respectively) while strain DLLS-108T had Hsl. salina CBA1114T as its nearest neighbour (97.7-97.8 and 95.9 % similarities, respectively) and was separated from Hsl. limicola LT12T (94.4-95.8 and 93.4 % similarities, respectively). These clusters represented two distinct novel species as indicated by phenotypic characteristics, polar lipid compositions and whole-genome comparisons. Diverse phenotypic characteristics, morphology and growth characteristics, nutrition and miscellaneous biochemical tests differentiate strains DL-M4T, LYG-109, DLLS-108T from Hsl. limicola LT12T and Hsl. salina CBA1114T. Strains DL-M4T and LYG-109 contained phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and three unidentified glycolipids, while strain DLLS-108T contained these polar lipids and two unidentified phospholipids. The major respiratory quinones detected in the three isolates were menaquinone MK-8 and MK-8(H2). The average nucleotide identity (ANI) and in silico DNA-DNA hybridization (isDDH) values between the isolated strains and the current two members of Halostella were found to be 79.3-86.6 (ANI) and 22.9-49.8 % (isDDH). All these results showed that the three isolates represent two novel species of the genus Halostella for which the names Halostella pelagica sp. nov. [type strain dl-M4T (=CGMCC 1.13603T=JCM 32954T)] and Halostella litorea sp. nov. [type strain DLLS-108T(=CGMCC 1.13610T=JCM 32955T)] are proposed.

Natronorubrum halophilum sp. nov. isolated from two inland salt lakes.

Two halophilic archaeal strains, SHR37T and NEN6, were isolated from salt lakes located in the Tibet and Xinjiang regions of China. The two strains were found to form a single cluster (99.9% and 99.3% similarity, respectively) separating them from the six current members of Natronorubrum (94.7-96.9% and 86.1-90.8% similarity, respectively) on the basis of the 16S rRNA and rpoB' gene sequence similarities and phylogenetic analysis. Diverse phenotypic characteristics differentiate strains SHR37T and NEN6 from current Natronorubrum members. Their polar lipids are C20C20 and C20C25glycerol diether derivatives of PG, PGP-Me, and a major gycolipid chromatographically identical to disulfated mannosyl glucosyl diether (S2-DGD). Four minor unidentified gycolipids are also present. The OrthoANI and in silico DDH values of the two strains were 97.3% and 76.1%, respectively, which were much higher than the threshold values proposed as a species boundary (ANI 95-96% and in silico DDH 70%), which revealed that the two strains represent one species; the two values (ANI 79.0-81.9% and in silico DDH 23.5-25.7%) of the strains examined in this study and the current members of Natronorubrum are much lower than the recommended threshold values, suggesting that strains SHR37T and NEN6 represent a genomically different species of Natronorubrum. These results showed that strains SHR37T (= CGMCC 1.15233T = JCM 30845T) and NEN6 (= CGMCC 1.17161) represent a novel species of Natronorubrum, for which the name Natronorubrum halophilum sp. nov. is proposed.

Halomicrococcus hydrotolerans gen. nov., sp. nov., an extremely halophilic archaeon isolated from a subterranean salt deposit.

A halophilic archaeon, strain H22T, was isolated from a subterranean salt deposit sampled at Yunnan salt mine, PR China. Colonies of strain H22T were light pink-pigmented. Cells were coccus, non-motile, Gram-stain-negative, and did not lyse in distilled water. The strain was aerobic and grew at 20-55 °C (optimum, 37 °C), in the presence of 10-30 % (w/v) NaCl (20 %) and at pH 6.5-9.0 (pH 7.0). Mg2+ was required for growth (optimum, 0.005 M). Major polar lipids were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and sulfated mannosyl-glucosyl-glycerol diether-1. Sequence similarity search based on the multiple 16S rRNA genes (rrnA, rrnB and rrnC) of strain H22T revealed that it was most closely related to species of the genera Haloarchaeobius, Haladaptatus, Halorussus and Halorubellus with relative low sequence similarities (91.9-93.7 %). The strain, however, shared highest rpoB' gene sequence identities with Halorussus rarus TBN4T (90.8 % rpoB' gene sequence similarity). Phylogenetic trees based on 16S rRNA and rpoB' gene sequences revealed a robust lineage of the strain H22T with members of related genera of the family Halobacteriaceae. The DNA G+C content of strain H22T was 62.9 mol%. Genome-based analysis of average nucleotide identity (ANI) and in silico DNA-DNA hybridization (DDH) between strains H22T and its closest relative were equal or lower than 77.7 and 22.4 %, respectively, which were far below the threshold for delineation of a new species. Based on ANI values, in silico DDH, and distinct morphological and physiological differences from the previously described taxa, we suggest that strain H22T represents a novel species of a new genus within the family Halobacteriaceae, for which the name Halomicrococcus hydrotolerans gen. nov., sp. nov. is proposed. The type strain is H22T (=CGMCC 1.16291T=NBRC 113231T).

Halostella limicola sp. nov., isolated from saline soil sampled at the Tarim Basin.

A halophilic archaeaon, strain LT12T, was isolated from saline soil sampled at the Tarim Basin, PR China. The novel strain stained Gram-negative, cells were rod-shaped, and formed light red-pigmented colonies on agar plate. Strain LT12T grew optimally at 3.1 M NaCl, 0.05 M MgCl2, 37 °C and pH 7.5. The cells lysed in distilled water and the minimal NaCl concentration to prevent cell lysis was 1.4 M. Based on the results of phylogenetic analyses of the 16S rRNA and rpoB' genes, strain LT12T was most closely related to Halostella salina CBA1114T(94.4-95.9  and 93.6 % similarities, respectively). The average nucleotide identity and in silico DNA-DNA hybridization values between strain LT12T and H. salina CBA1114T were 81.0 and 24.3 %, respectively. The major polar lipids of strain LT12T were phosphatidic acid, phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and three unidentified glycolipids. The DNA G+C content was 67.2 mol % (genome). Based on the phenotypic, chemotaxonomic and phylogenetic properties, strain LT12T represents a novel species of the genus Halostella for which the name Halostellalimicola sp. nov. is proposed. The type strain is LT12T (=CGMCC 1.14941T=JCM 30667T).

Halorientalis pallida sp. nov., an extremely halophilic archaeon isolated from a marine saltern.

An extremely halophilic archaeon, strain F13-25T, was isolated from a marine saltern located in Isla Cristina, Huelva, on the south-west coast of Spain. The novel strain had pink-pigmented, non-motile, coccoid cells. Optimal growth was achieved at 25 % (w/v) NaCl, pH 7.5 and 37 °C. Strain F13-25T possessed two heterogeneous 16S rRNA genes (rrnA and rrnB) most closely related to Halorientalis persicus D108T (97.6-99.2 % sequence similarity) and Halorientalis regularis TNN28T (95.9-98.8 %). On the basis of the results of rpoB' gene sequence analysis, strain F13-25T was also closely related to Halorientalis persicus IBRC-M 10043T (89.9 %) and Halorientalis regularis TNN28T (92.3 %). Relatedness values, computed using the Genome-to-Genome Distance Calculator, between strain F13-25T and Halorientalis persicus IBRC-M 10043T and Halorientalis regularis IBRC-M 10760T were 34.6 and 36.2 %, respectively. Average nucleotide identity values based on orthoANI, ANIb and ANIm of strain F13-25T and Halorientalis persicus IBRC-M 10043T and Halorientalisregularis IBRC-M 10760T were 88.0 and 88.8, 87.1 and 87.6 %, and 89.2 and 89.6 %, respectively. All values were far below the threshold accepted for prokaryotic species delineation. The major polar lipids were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and one glycolipid chromatographically identical to sulfated diglycosyl diether. The DNA G+C content was 65.7 mol% (genome). The results of phylogenetic, phenotypic and chemotaxonomic analyses indicated that strain F13-25T represents a novel species of the genus Halorientalis, for which the name Halorientalis pallida sp. nov., with type strain F13-25T (=CECT 9384T=IBRC-M 11176T), is proposed.

Natronolimnobius sulfurireducens sp. nov. and Halalkaliarchaeum desulfuricum gen. nov., sp. nov., the first sulfur-respiring alkaliphilic haloarchaea from hypersaline alkaline lakes.

Eight pure cultures of alkaliphilic haloaloarchaea capable of growth by dissimilatory sulfur reduction (previously only shown for neutrophilic haloarchaea) were isolated from hypersaline alkaline lakes in different geographic locations. These anaerobic enrichments, inoculated with sediments and brines, used formate, butyrate and peptone as electron donors and elemental sulfur as an electron acceptor 4 M total Na+ and at pH 9-10. According to 16S rRNA gene sequencing, the isolates fell into two distinct groups. A major group, comprising seven obligate alkaliphilic isolates from highly alkaline soda lakes, represents a new species-level branch within the genus Natronolimnobius (order Natrialbales), while a single moderately alkaliphilic isolate from the less alkaline Searles Lake forms a novel genus-level lineage within the order Haloferacales. The cells of the isolates are either flat rods or coccoid. They are facultative anaerobes using formate or H2 (in the presence of acetate or yeast extract as carbon source), C4-C9 fatty acids or peptone (the major group) as electron donors and either sulfur or DMSO (the major group) as electron acceptors. Aerobic growth is only possible with organic acids and peptone-yeast extract. All isolates are extreme halophiles, growing optimally at 4 M total Na+. On the basis of their unique physiological properties and distinct phylogeny, we propose that the seven isolates from the soda lakes are placed into a novel species, Natronolimnobiussulfurireducens sp. nov. (type strain AArc1T=JCM 30663T=UNIQEM U932T), and the Searles Lake isolate, AArc-SlT, into a new genus and species Halalkaliarchaeum desulfuricum (=JCM 30664T=UNIQEM U999T).

Haloterrigena salifodinae sp. nov., an extremely halophilic archaeon isolated from a subterranean rock salt.

A novel extremely halophilic strain, designated ZY19T, was isolated from a rock salt sample from Yunnan salt mine, PR China. Strain ZY19T is neutrophilic, non-motile and requires at least 10% (w/v) NaCl for growth. Optimal growth is observed at 20-25% (w/v) NaCl, pH 7.5-8.0 and 42 °C. Mg2+ is not required for growth. The cells do not lyse in distilled water. On the basis of 16S rRNA gene sequence analysis, strain ZY19T belongs to the genus Haloterrigena (Htg.) and is closely related to Haloterrigena salina XH-65T (98.5% sequence similarity) and Haloterrigena turkmenica DSM 5511T (97.9%). Phylogenetic and phylogenomic analysis showed that strain ZY19T clusters with the species Htg. salina and Htg. turkmenica forming an independent clade separated from other members of the genus. The value of genomic average nucleotide identity (ANI) between strains ZY19T and its close relative, Htg. salina XH-65T was 94.2%. DNA-DNA relatedness between strains ZY19T and Htg. salina XH-65T revealed by in silico DNA-DNA hybridization (DDH) was 56.3%. Both the ANI value and the degree of in silico DDH are below the accepted threshold for members of the same species. The major polar lipids were found to consist of phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, sulfated diglycosyl-diether-1 and mannose-2, 6-disulfate (1 → 2)-glucose glycerol diether. The genomic DNA G+C content was determined to be 64.5 mol%. Based on the results of the phenotypic, chemotaxonomic, genetic similarity and inferred phylogeny, strain ZY19T is distinct from other validly named species and thus represents a novel species within the genus Haloterrigena, for which the name Haloterrigena salifodinae sp. nov. is proposed. The type strain is ZY19T (=CGMCC 1.16114T=NBRC 112981T).

Halonotius aquaticus sp. nov., a new haloarchaeon isolated from a marine saltern.

A halophilic archaeon, strain F13-13T, was isolated from a marine saltern located in Isla Cristina, Huelva, on the south-west coast of Spain. It was a Gram-stain-negative, motile and aerobic haloarchaeon. It grew at 28-50 °C (optimum, 37 °C), pH 6.0-8.5 (pH 7.5) and in 15-30 % (w/v) total salts (25 %). Phylogenetic analyses based on the 16S rRNA gene sequences showed that strain F13-13T is a member of the genus Halonotius, the most closely related species being Halonotius pteroides 1.15.5T (96.7 % sequence similarity). The 16S rRNA gene sequence similarity to species of other genera is lower than 93.4 %. Strain F13-13T was also found to be closely related to Halonotius pteroides 1.15.5T (91.4 %) on the basis of rpoB' gene sequence analysis. The Genome-to-Genome Distance Calculator relatedness result between strain F13-13T and Halonotius pteroides CECT 7525T was 35 %, a value lower than the 70 % threshold accepted for species delineation. The average nucleotide identity values based on OrthoANI, ANIb and ANIm of strain F13-13T and Halonotius pteroides CECT 7525T were 88.7, 87.8 and 89.4 %, respectively, these values are also lower than the threshold accepted for species delineation. The DNA G+C content of this isolate was 61.2 mol%. The major lipids of strain F13-13T were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate and sulphated diglycosyl diether. Based on the phylogenetic, phenotypic, genotypic and chemotaxonomic characterization, we propose the placement of strain F13-13T as a new species within the genus Halonotius, with the name Halonotius aquaticus sp. nov. The type strain is F13-13T (=CECT 9386T=IBRC-M 11204T).

Halalkalicoccus subterraneus sp. nov., an extremely halophilic archaeon isolated from a subterranean halite deposit.

An extremely halophilic archaeon, designated strain GSM28T, was isolated from a subterranean halite deposit in a Yunnan salt mine, China. Cells of the strain were observed to be cocci, non-motile and Gram-variable, and to require at least 15% (w/v) NaCl for growth (optimum 20%). Growth was found to occur in the ranges of 20-45 °C (optimum 42 °C) and pH 6.0-8.5 (optimum 7.5). Cells did not lyse in distilled water. Phylogenetic analysis based on 16S rRNA gene sequences indicated that this strain belongs to the genus Halalkalicoccus and shows 99.1% similarities with its close phylogenetic relative Halalkalicoccus paucihalophilus DSM 24557T. Genomic ANI analysis showed that the DNA-DNA relatedness between strain GSM28T and the closely related species Hac. paucihalophilus DSM 24557T and Halalkalicoccus jeotgali B3T was 83.7% and 83.1%, respectively. The major polar lipids were determined to be phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate, sulfated mannosyl-glucosyl-glycerol diether-1 and two unidentified glycolipids. The DNA G + C content was determined to be 61.8 mol %. On the basis of physiological, biochemical tests and phylogenetic differentiations, strain GSM28T is concluded to represent a novel species in the genus Halalkalicoccus, for which the name Halalkalicoccus subterraneus sp. nov. is proposed. The type strain is GSM28T (= CGMCC 1.16344T = NBRC 113432T).