EzBioCloud: a genome-driven database and platform for microbiome identification and discovery.

With the continued evolution of DNA sequencing technologies, the role of genome sequence data has become more integral in the classification and identification of Bacteria and Archaea. Six years after introducing EzBioCloud, an integrated platform representing the taxonomic hierarchy of Bacteria and Archaea through quality-controlled 16S rRNA gene and genome sequences, we present an updated version, that further refines and expands its capabilities. The current update recognizes the growing need for accurate taxonomic information as defining a species increasingly relies on genome sequence comparisons. We also incorporated an advanced strategy for addressing underrepresented or less studied lineages, bolstering the comprehensiveness and accuracy of our database. Our rigorous quality control protocols remain, where whole-genome assemblies from the NCBI Assembly Database undergo stringent screening to remove low-quality sequence data. These are then passed through our enhanced identification bioinformatics pipeline which initiates a 16S rRNA gene similarity search and then calculates the average nucleotide identity (ANI). For genome sequences lacking a 16S rRNA sequence and without a closely related genomic representative for ANI calculation, we apply a different ANI approach using bacterial core genes for improved taxonomic placement (core gene ANI, cgANI). Because of the increase in genome sequences available in NCBI and our newly introduced cgANI method, EzBioCloud now encompasses a total of 109 835 species, of which 21 964 have validly published names. 47 896 are candidate species identified either through 16S rRNA sequence similarity (phylotypes) or through whole genome ANI (genomospecies), and the remaining 39 975 were positioned in the taxonomic tree by cgANI (species clusters). Our EzBioCloud database is accessible at www.ezbiocloud.net/db.

Rhodoferax lacus sp. nov., isolated from a large freshwater lake.

A Gram-staining-negative, aerobic, motile with a single polar flagellum and rod-shaped bacterium as a bacterial host of podovirus P26218, designated IMCC26218T, was isolated from Lake Soyang, South Korea. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain IMCC26218T belonged to the genus Rhodoferax of the family Comamonadaceae and shared 97.7-99.0 % sequence similarities with Rhodoferax species. The draft whole genome sequence of strain IMCC26218T was ca. 4.9 Mbp in size with the DNA G+C content of 62.3 mol%. Average nucleotide identity (ANI) and digital DNA-DNA hybridisation (dDDH) values between strain IMCC26218T and other Rhodoferax were 74.0-77.3 % and 19.5-21.0 %, respectively, showing that the strain represents a new Rhodoferax species. The strain contained summed feature 3 (C16 : 1 ω6c and/or C16 : 1 ω7c) and C16 : 0 as the major fatty acids and phosphatidylethanolamine, three unidentified phospholipids, two unidentified aminolipids and two unidentified lipids as major polar lipids. The predominant isoprenoid quinone of the strain was ubiquinone-8 (Q-8). On the basis of the phylogenetic and phenotypic characteristics, strain IMCC26218T is considered to represent a novel species of the genus Rhodoferax, for which the name Rhodoferax lacus sp. nov. is proposed. The type strain is IMCC26218T (=KACC 18983T=NBRC 112709T).

Flavobacterium lacicola sp. nov., isolated from a freshwater lake.

A bacterial strain, designated IMCC25901T, was isolated from a freshwater lake, Soyang, in the Republic of Korea. The strain was Gram-stain-negative, aerobic, non-motile, orange-coloured and short rod-shaped. The 16S rRNA gene sequence analysis showed that strain IMCC25901T was most closely related to Flavobacterium yonginense HMD1001T (97.0 %) and formed a robust phylogenetic clade with other species of the genus Flavobacterium. Growth of strain IMCC25901T was observed at 10-30 °C (optimum, 20 °C), pH 6-8 (optimum, pH 7) and 0-1.0 % NaCl (optimum, 0 %). The DNA G+C content of strain IMCC25901T was 34.2 mol%. The major fatty acid constituents of the strain were anteiso-C15 : 0, summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c) and iso-C15 : 0. Cells of strain IMCC25901T contained phosphatidylethanolamine, an unidentified phospholipid, two unidentified aminolipids and two unidentified lipids. The isoprenoid quinone detected in the strain was MK-6. On the basis of the taxonomic data obtained in this study, it was concluded that strain IMCC25901T represented a novel species in the genus Flavobacterium, for which the name Flavobacterium lacicola sp. nov. is proposed. The type strain of Flavobacterium lacicola is IMCC25901T (=KCTC 52571T=NBRC 112883T).

Deinococcus lacus sp. nov., a gamma radiation-resistant bacterium isolated from an artificial freshwater pond.

A Gram-stain-negative, pink-coloured, non-motile and gamma radiation-resistant bacterium, designated strain IMCC1711T, was isolated from a freshwater sample collected from an artificial pond (Inkyong Pond). The 16S rRNA gene sequence analysis showed that strain IMCC1711T was most closely related to Deinococcus piscis 3axT (94.2 %) and formed a robust phylogenetic clade with other species of the genus Deinococcus. Optimal growth of strain MCC1711T was observed at 25 °C and pH 7.0 without NaCl. Strain IMCC1711T exhibited high resistance to gamma radiation. The DNA G+C content of strain IMCC1711T was 59.1 mol% and MK-8 was the predominant isoprenoid quinone. Major fatty acid constituents of the strain were C17 : 1ω8c, C16 : 0, summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c) and C15 : 1ω6c. The major polar lipids constituted phosphatidylethanolamine, one unidentified phosphoglycolipid and two unidentified glycolipids. On the basis of taxonomic data obtained in this study, it was concluded that strain IMCC1711T represented a novel species of the genus Deinococcus, for which the name Deinococcus lacus sp. nov. is proposed. The type strain of Deinococcus lacus is IMCC1711T (KCTC 52494T=KACC 18979T=NBRC 112440T).

Flavobacterium chuncheonense sp. nov. and Flavobacterium luteum sp. nov., isolated from a freshwater lake.

Two Gram-staining-negative, orange coloured, non-motile, rod-shaped bacterial strains, designated strains IMCC26013T and IMCC26026T, were isolated from a freshwater sample collected from Lake Soyang in Korea. The 16S rRNA gene-based phylogenetic analyses showed that both strains belonged to the genus Flavobacterium and that strains IMCC26013T and IMCC26026T were most closely related to Flavobacterium psychrophilum (96.5 %) and Flavobacterium myungsuense (97.7 %), respectively. DNA G+C contents of strains IMCC26013T and IMCC26026T were 37.8 and 33.7 mol%, respectively. DNA-DNA relatedness between strain IMCC26026T and F. myungsuense HMD1033T was 56.4 %, showing a novel species status of strain IMCC26026T. Major fatty acid constituents (>10 %) of strain IMCC26013T were iso-C15 : 1 G, C15 : 1 ω6c, C17 : 1 ω6c and summed feature 3 (C16 : 1 ω6c and/or C16 : 1 ω7c) and those of strain IMCC26026T were iso-C15 : 0, anteiso-C15 : 0 and summed feature 3. Respiratory quinone detected in the two strains was MK-6. Both strains contained phosphatidylethanolamine as a major polar lipid. On the basis of these results, strains IMCC26013T and IMCC26026T were considered to represent novel species in the genus Flavobacterium, for which the names Flavobacterium chuncheonense (type strain IMCC26013T=KCTC 52573T=NBRC 112526T), and Flavobacterium luteum (type strain IMCC26026T=KCTC 52572T=NBRC 112527T) are proposed, respectively.

Flavobacterium soyangense sp. nov., a psychrotolerant bacterium, isolated from an oligotrophic freshwater lake.

A bacterial strain, designated IMCC26223T, was isolated from an oligotrophic freshwater lake, Lake Soyang, Korea. Cells of strain IMCC26223T were Gram-staining negative, strictly aerobic, non-motile and short-rod-shaped. Growth occurred at pH 6-8 (optimum, pH 7.0), at 4-25 °C (optimum, 15 °C) and with 0-0.5 % (w/v) NaCl (optimum, 0 %). Phylogenetic analyses based on 16S rRNA gene sequences showed that strain IMCC26223T was identified as a member of the genus Flavobacterium and most closely related to Flavobacterium fluvii H7T (97.6 %), Flavobacterium segetis AT1048T (97.5 %) and Flavobacterium weaverense AT1042T (97.2 %). DNA-DNA relatedness between strain IMCC26223T and F. fluvii H7T was 41.5-51.7 % in the reciprocal hybridization. Strain IMCC26223T contained MK-6 as the major respiratory quinone. The major cellular fatty acids consisted of C16 : 0, iso-C15 : 0, anteiso-C15 : 0 and summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c), and the polar lipids were phosphatidylethanolamine, an unidentified aminolipid and two unidentified lipids. The DNA G+C content of strain IMCC26223T was 34.5 mol%. On the basis of 16S rRNA gene phylogeny and phenotypic characterization, strain IMCC26223T represents a novel species of the genus Flavobacterium, for which the name Flavobacterium soyangense sp. nov., is proposed. The type strain is IMCC26223T (=KCTC 52245T=JCM 31384T).

Flavobacterium inkyongense sp. nov., isolated from an artificial freshwater pond.

A Gram-stain-negative, non-motile, yellow-pigmented bacterium, designated strain IMCC27201T, was isolated from an artificial freshwater pond (Inkyong) in Korea. Growth of strain IMCC27201T occurred at 10-37 °C (optimum, 30 °C), at pH 7.0-8.0 (optimum, pH 7.0) and with 0-0.25 % (w/v) NaCl (optimum, 0 %). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain IMCC27201T belonged to the genus Flavobacterium and was related most closely to Flavobacterium columnare IFO 15943T (97.8 % sequence similarity), Flavobacterium terrae R2A1-13T (97.2 %) and Flavobacterium vireti THG-SM1T (96.4 %). Strain IMCC27201T exhibited low DNA-DNA relatedness with F. columnare KCTC 42885T (34.9-40.6 %). The DNA G+C content of strain IMCC27201T was 32.1 mol%. The major fatty acids were iso-C15 : 0, iso-C15 : 1 G and iso-C15 : 0 3-OH. Strain IMCC27201T contained menaquinone-6 (MK-6) as the sole isoprenoid quinone. The polar lipids of strain IMCC27201T consisted of phosphatidylethanolamine, three unidentified aminolipids and two unidentified lipids. Based on 16S rRNA gene phylogeny, phenotypic characterization and DNA-DNA relatedness, strain IMCC27201Trepresents a novel species of the genus Flavobacterium, for which the name Flavobacterium inkyongense sp. nov. is proposed. The type strain is IMCC27201T (=KCTC 52244T=JCM 31385T).

Emticiciafontis sp. nov., isolated from a freshwater pond.

A bacterial strain, designated IMCC1731T, was isolated from an eutrophic freshwater pond and characterized using a polyphasic taxonomic approach. Cellular growth occurred at pH 6-9 (optimum, pH 8.0), at 10-30 °C (optimum, 25 °C) and with 0-1 % (w/v) NaCl (optimum, 0 %). Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain IMCC1731T belonged to the genus Emticicia in the family Cytophagaceae and was most closely related to Emticicia ginsengisoli Gsoil 085T (98.1 %) followed by Emticicia paludis HMF3850T (95.0 %), Emticicia oligotrophica DSM 17448T (94.7 %), Emticicia aquatica HMF2925T (94.4 %) and Emticicia sediminis JBR12T (94.0 %). The DNA-DNA relatedness between strain IMCC1731T and E. ginsengisoli Gsoil 085T was 47±4 %. The DNA G+C content of strain IMCC1731T was 37.7 mol%. The predominant cellular fatty acids were summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c) and iso-C15 : 0. Based on the physiological and chemotaxonomic characteristics, DNA-DNA relatedness and 16S rRNA gene phylogeny, stain IMCC1731T is considered to represent a novel species of the genus Emticicia, for which the name Emticicia fontis sp. nov. is proposed. The type strain is IMCC1731T (=KCTC 52248T=JCM 31373T).