Halostreptopolyspora alba gen. nov., sp. nov., a halophilic actinobacterium isolated from saline soil of Xinjiang, Northwest of China.

A Gram-stain-positive, aerobic, moderate halophilic actinobacterium, designated strain YIM 96095T, was isolated from a saline soil sample collected from Aiding Lake, Xinjiang, North-western China. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the isolate belonged to the family Nocardiopsidaceae, formed a distinct subclade, and was most closely related to Lipingzhangella halophila DSM 102030T and Allosalinactinospora lopnorensis DSM 45697T with sequence identity values of 95.8 and 95.1%, respectively. Optimal growth occurred at 37 °C, pH 7.0-8.0 and with 5-16% (w/v) NaCl, with well-developed, non-fragmented substrate mycelia and single-, double-, or triple-wrinkled spore(s) on the mature aerial hyphae. The chemical analysis presented meso-diaminopimelic acid as the diagnostic diamino acid of the cell-wall peptidoglycan, and glucose, galactose and rhamnose as the major whole-cell sugars, and iso-C15 : 0 and anteiso-C15 : 0 as the major fatty acids. The phospholipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, unidentified phospholipids and unidentified glycolipid. The menaquinones were MK-10(H8), MK-10(H6) and MK-9(H10). Its G+C content was 69.7 mol% in the determined genome sequence. Based on phenotypic, chemotaxonomic and phylogenetic characteristics, a novel genus and species named Halostreptopolyspora alba gen. nov., sp. nov. is proposed for isolate YIM 96095T (=KCTC 49266T=CGMCC 4.7636T).

Dyadobacter diqingensis sp. nov., isolated from Baima snow mountain of Diqing Tibetan Autonomous Prefecture in Yunnan province, south-west China.

A Gram-negative, aerobic, nonmotile, rod-shaped and yellow-pigment-producing bacteria was isolated from Baima snow mountain of Diqing Tibetan Autonomous Prefecture in Yunnan province, south-west China and characterized using a polyphasic approach. The results of 16S rRNA gene sequence similarity analysis showed that strain YIM B04101T was closely related to the type strain of Dyadobacter koreensis DSM 19938T (97.81%) and Dyadobacter frigoris AR-3-8T (97.95%). The predominant respiratory quinone was menaquinone-7 (MK-7). The major polar lipid was phosphatidylethanolamine. The major fatty acids were summed feature 3 (C16:1ω7c/C16:1ω6c), C18:1ω9c and C16:0. The DNA G + C content was 43.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain YIM B04101T belonged to a cluster comprising species of the genus Dyadobacter. However, it differed from its closest relative, Dyadobacter koreensis KCTC 12537T and Dyadobacter frigoris AR-3-8T, in many physiological properties. Based on these phenotypic characteristics and phylogenetic distinctiveness, strain YIM B04101T is considered to be a novel species of the genus Dyadobacter, for which the name Dyadobacter diqingensis sp. nov. is proposed. The type strain is YIM B04101T (= CGMCC 1.19249T = CCTCC AB 2021270).

Halomonas faecis sp. nov., a halophilic bacterium isolated from human faeces.

A novel moderately halophilic, Gram-stain-negative, catalase- and oxidase-positive, strictly aerobic, non-sporulating, non-motile rod, designated strain JSM 104105 T, was isolated from human faeces. Strain JSM 104105 T was able to grow with 0.5-18% (w/v) NaCl (optimum 4-9%), at pH 6-10.5 (optimum pH 7-8) and at 10-40 °C (optimum 30 °C) in complex media. The major cellular fatty acids were C18:1ω7c, C16:0, C16:1ω7c and/or C16:1ω6c, C19:0 cyclo ω8c and C12:0 3-OH. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an unidentified aminophospholipid, an unidentified glycolipid and three unidentified phospholipids. The predominant respiratory quinone was Q-9 and the genomic DNA G + C content was 64.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain JSM 104105 T should be assigned to the genus Halomonas, and was most closely related to Halomonas gudaonensis SL014B-69 T (99.0% sequence similarity), followed by Halomonas azerbaijanica TBZ202T (98.6%) and Halomonas lysinitropha 3(2)T (97.3%). The whole genomic analysis showed that strain JSM 104105 T constituted a different taxon separated from the recognized Halomonas species. Combined data from phenotypic and genotypic studies demonstrated that strain JSM 104105 T represents a new species of the genus Halomonas, for which the name Halomonas faecis sp. nov. is proposed. The type strain is JSM 104105 T (= CCTCC AB 2014160 T = CGMCC 1.12945 T = KCTC 42146 T).

Aidingimonas lacisalsi sp. nov., isolated from a salt lake in China.

A novel bacterium, XHU 5135T, belonging to the genus Aidingimonas, was isolated from a salt lake sample collected in Xinjiang Province, north-west PR China. The isolate was Gram-stain-negative, rod-shaped and non-motile. The strain was catalase-positive and oxidase-negative. Growth occurred at NaCl concentrations of 5-25 % (optimum, 10-13 %), at 13-41 °C (35-37 °C) and at pH 6.0-10.0 (pH 7.0-8.0). The predominant ubiquinone was Q-9. The major fatty acids were C19 : 0 cyclo ω8c and C16 : 0. The G+C content of the genomic DNA was 58.1 mol%. The affiliation of strain XHU 5135T with the genus Aidingimonas was confirmed by 16S rRNA gene sequence comparisons. The closest type strain was Aidingimonas halophile YIM 90637T, which showed a 16S rRNA gene sequence similarity of 97.5 %. The ANI value between XHU 5135T and the closest type strain was 80.01 %. The estimated digital DNA-DNA hybridization estimate value between strain XHU 5135T and the closest type strain was 22.80 %. Phenotypically, the characteristics of XHU 5135T were shown to differ from the most closely related species, A. halophila. On the basis of the data from this polyphasic study, strain XHU 5135T represents a novel species of the genus Aidingimonas, for which the name Aidingimonas lacisalsi sp. nov. is proposed. The type strain is strain XHU 5135T (=CCTCC AB 2016344T=KCTC 42945T=DSM 104700T).

Vallicoccus soli gen. nov., sp. nov., a novel actinobacterium isolated from soil, and description of Vallicoccaceae fam. nov., Motilibacterales ord. nov.

A novel Gram-stain-positive, aerobic, cocci-shaped actinobacterium, designated YIM 75000T, was isolated from a soil sample collected from a dry-hot river valley in Yunnan Province, P.R. China. Growth was observed at 10-45 °C (optimal 37 °C), 0-8% (w/v) NaCl (optimal at 0-3% NaCl) and pH 6.0-8.0 (optimal at pH 7.3). The peptidoglycan contained LL-diaminopimelic acid, glycine, glutamic acid as well as alanine and its type was A3γ with an LL-Dpm-Gly interpeptide bridge. The major cellular fatty acids (> 10%) were C16:0, Summed In Feature 3 (C16:1 ω6c/C16:1 ω7c) and C17:1 ω8c. The predominant menaquinone was MK-9(H4). The major whole-cell sugars contained rhamnose, ribose, arabinose and mannose. The DNA G+C content was 77.0 mol%. The 16S rRNA gene sequence similarities of strain YIM 75000T with other species were less than 94%. Phylogenetic analyses based on 16S rRNA gene sequences and genome data, revealed that strain YIM 75000T together with the genus Motilibacter formed a distinct phylogenetic lineage within the phylum Actinobacteria, separating them from members of all orders. Strain YIM 75000T showed 73.4-73.7% average nucleotide identity and 19.5-19.7% digital DNA-DNA hybridization identity with the closely related genus Motilibacter. Based on the phenotypic, phylogenetic and chemotaxonomic data, it is proposed that the new isolate represents the nomenclature type of the novel species Vallicoccus soli gen. nov., sp. nov. (YIM 75000T = DSM 45377T = KCTC 49228T = CGMCC 1.13844T) which is the nomenclature type of the novel genus Vallicoccus gen. nov. within Vallicoccaceae fam. nov and Motilibacterales ord. nov in the phylum Actinobacteria. The family Vallicoccaceae fam. nov. and the order Motilibacterales (contains Vallicoccaceae fam. nov. and Motilibacteraceae Lee 2013) ord. nov. are formally proposed.

Phytoactinopolyspora halophila sp. nov., a halophilic actinomycete isolated from a saline soil.

A novel halophilic actinobacterial strain, designated YIM 96934T, was isolated from a soil sample collected from the edge of a saline lake in Xinjiang, north-west China. The taxonomic position of the strain was investigated using a polyphasic approach. Cells of the strain were aerobic and Gram-stain-positive. On the basis of 16S rRNA gene sequence analysis, strain YIM 96934T was related most closely to type strains of the genus Phytoactinopolyspora, and shared highest sequence similarity with Phytoactinopolyspora endophytica EGI 60009T (94.7 %), Phytoactinopolyspora alkaliphila EGI 80629T (94.5 %) and Phytoactinopolyspora halotolerans YIM 96448T (94.1 %). Optimum growth of the strain was observed at 28-37 °C (range 15-45 °C), pH 7.0-8.0 (6.0-9.0) and 5-8 % (w/v) NaCl (2-24 %). The major isoprenoid quinone was MK-9(H4). The whole-cell sugars were glucose, galactose, mannose and rhamnose. The diagnostic diamino acid was ll-diaminopimelic acid. The polar lipid profile was found to consist of diphosphatidylglycerol, four unidentified phospholipids, three unidentified phosphoglycolipids, an unidentified aminophospholipid, two phosphatidylinositol mannosides and an unidentified polar lipid. The major fatty acids were anteiso-C15 : 0, iso-C16 : 0, iso-C17 : 0, anteiso-C17 : 0 and summed feature 4 (iso-C17 : 1 I and/or anteiso-C17 : 1 B). The DNA G+C content was 66.6 mol%. On the basis of phenotypic, genotypic and phylogenetic data, a novel species, Phytoactinopolyspora halophila sp. nov., is proposed. The type strain is YIM 96934T (=KCTC 39926T=CCTCC AB 2017057T).

Bailinhaonella thermotolerans gen. nov., sp. nov., a new member of the order Streptosporangiales.

A Gram-positive, aerobic, non-motile actinobacterium, designated YIM 75507T, that was isolated from a soil sample collected from a dry-hot valley, was subjected to a polyphasic taxonomic study. The isolate formed branched hyphae and no fragmentation was found. Clustered spore chains were borne from aerial mycelium. The cell-wall peptidoglycan contained glutamic acid, alanine and meso-diaminopimelic acid. Whole-cell sugars were galactose, mannose, glucosamine, glucose and ribose. The major menaquinones were MK-9(H6), MK-9(H8) and MK-10(H6). The polar phospholipids contained phosphatidylmethylethanolamine, phosphatidylethanolamine and ninhydrin-positive phosphoglycolipid. Major fatty acids were iso-C16 : 0 and 10-methyl-C17 : 0. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain YIM 75507T formed a stable and distinct lineage clustered with the genus Sinosporangium in the family Streptosporangiaceae. The draft genome sequence of strain YIM 75507T exhibited low average nucleotide identity to the closest related strain, Sinosporangium album CPCC 201354T (83.97 %), well below the 95-96 % species circumscription threshold. The G+C content of the genomic DNA was 73.8 mol%. On the basis of morphological, chemotaxonomic and phylogenetic evidence, strain YIM 75507T is assigned to a novel species of a new genus, for which the name Bailinhaonella thermotolerans gen. nov., sp. nov. is proposed. The type strain of Bailinhaonella thermotolerans is YIM 75507T (=KCTC 49229T=CGMCC 4.7547T).

Cellular differentiation into hyphae and spores in halophilic archaea.

Several groups of bacteria have complex life cycles involving cellular differentiation and multicellular structures. For example, actinobacteria of the genus Streptomyces form multicellular vegetative hyphae, aerial hyphae, and spores. However, similar life cycles have not yet been described for archaea. Here, we show that several haloarchaea of the family Halobacteriaceae display a life cycle resembling that of Streptomyces bacteria. Strain YIM 93972 (isolated from a salt marsh) undergoes cellular differentiation into mycelia and spores. Other closely related strains are also able to form mycelia, and comparative genomic analyses point to gene signatures (apparent gain or loss of certain genes) that are shared by members of this clade within the Halobacteriaceae. Genomic, transcriptomic and proteomic analyses of non-differentiating mutants suggest that a Cdc48-family ATPase might be involved in cellular differentiation in strain YIM 93972. Additionally, a gene encoding a putative oligopeptide transporter from YIM 93972 can restore the ability to form hyphae in a Streptomyces coelicolor mutant that carries a deletion in a homologous gene cluster (bldKA-bldKE), suggesting functional equivalence. We propose strain YIM 93972 as representative of a new species in a new genus within the family Halobacteriaceae, for which the name Actinoarchaeum halophilum gen. nov., sp. nov. is herewith proposed. Our demonstration of a complex life cycle in a group of haloarchaea adds a new dimension to our understanding of the biological diversity and environmental adaptation of archaea.