scholarly journals A Genus Definition for Bacteria and Archaea Based on a Standard Genome Relatedness Index

mBio ◽  
2020 ◽  
Vol 11 (1) ◽  
Author(s):  
R. A. Barco ◽  
G. M. Garrity ◽  
J. J. Scott ◽  
J. P. Amend ◽  
K. H. Nealson ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Type Species ◽  
Nucleotide Identity ◽  
Emergent Properties ◽  
Rrna Gene ◽  
Average Nucleotide Identity ◽  
Taxonomic Marker ◽  
Type Strains ◽  
The 16S Rrna Gene

ABSTRACT Genus assignment is fundamental in the characterization of microbes, yet there is currently no unambiguous way to demarcate genera solely using standard genomic relatedness indices. Here, we propose an approach to demarcate genera that relies on the combined use of the average nucleotide identity, genome alignment fraction, and the distinction between type- and non-type species. More than 3,500 genomes representing type strains of species from >850 genera of either bacterial or archaeal lineages were tested. Over 140 genera were analyzed in detail within the taxonomic context of order/family. Significant genomic differences between members of a genus and type species of other genera in the same order/family were conserved in 94% of the cases. Nearly 90% (92% if polyphyletic genera are excluded) of the type strains were classified in agreement with current taxonomy. The 448 type strains that need reclassification directly impact 33% of the genera analyzed in detail. The results provide a first line of evidence that the combination of genomic indices provides added resolution to effectively demarcate genera within the taxonomic framework that is currently based on the 16S rRNA gene. We also identify the emergence of natural breakpoints at the genome level that can further help in the circumscription of taxa, increasing the proportion of directly impacted genera to at least 43% and pointing at inaccuracies on the use of the 16S rRNA gene as a taxonomic marker, despite its precision. Altogether, these results suggest that genomic coherence is an emergent property of genera in Bacteria and Archaea. IMPORTANCE In recent decades, the taxonomy of Bacteria and Archaea, and therefore genus designation, has been largely based on the use of a single ribosomal gene, the 16S rRNA gene, as a taxonomic marker. We propose an approach to delineate genera that excludes the direct use of the 16S rRNA gene and focuses on a standard genome relatedness index, the average nucleotide identity. Our findings are of importance to the microbiology community because the emergent properties of Bacteria and Archaea that are identified in this study will help assign genera with higher taxonomic resolution.

scholarly journals Description of Kribbella italica sp. nov., isolated from a Roman catacomb

2015 ◽  
Vol 65 (Pt_2) ◽  
pp. 491-496 ◽  
Author(s):  
Gareth J. Everest ◽  
Sarah M. Curtis ◽  
Filomena De Leo ◽  
Clara Urzì ◽  
Paul R. Meyers
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Dna Hybridization ◽  
Type Species ◽  
Rrna Gene ◽  
Content Type ◽  
Dna Relatedness ◽  
Link Type ◽  
Type Strains ◽  
The 16S Rrna Gene

A novel actinobacterium, strain BC637T, was isolated from a biodeteriogenic biofilm sample collected in 2009 in the Saint Callixstus Roman catacomb. The strain was found to belong to the genus Kribbella by analysis of the 16S rRNA gene. Phylogenetic analysis using the 16S rRNA gene and the gyrB, rpoB, relA, recA and atpD concatenated gene sequences showed that strain BC637T was most closely related to the type strains of Kribbella lupini and Kribbella endophytica . DNA–DNA hybridization experiments confirmed that strain BC637T is a genomic species that is distinct from its closest phylogenetic relatives, K. endophytica DSM 23718T (63 % DNA relatedness) and K. lupini LU14T (63 % DNA relatedness). Physiological comparisons showed that strain BC637T is phenotypically distinct from the type strains of K. endophytica and K. lupini . Thus, strain BC637T represents the type strain of a novel species, for which the name Kribella italica sp. nov. is proposed ( = DSM 28967T = NRRL B-59155T).

scholarly journals Cohnella fermenti sp. nov., isolated from a fermentation process

2020 ◽  
Vol 70 (4) ◽  
pp. 2602-2610 ◽  
Author(s):  
Shih-Yao Lin ◽  
Wen-Ming Chen ◽  
Asif Hameed ◽  
Guan-Hua Huang ◽  
Mei-Hua Hung ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Type Species ◽  
Nucleotide Identity ◽  
Whole Genome Sequencing Data ◽  
Rrna Gene ◽  
Average Nucleotide Identity ◽  
Content Type ◽  
Link Type ◽  
Vegetable Sample

A novel Gram-stain-positive, aerobic, motile with peritrichous flagella, rod-shaped bacterium, designated CC-MHH1044T, was isolated from a preserved vegetable sample. A polyphasic taxonomic approach was applied to the isolates in order to clarify its taxonomic position. Growth of the strain CC-MHH1044T occurred at 15–50 °C (optimum, 30 °C), pH 6.0–8.0 (optimum, pH 7.0) and with 0–2.0 % (w/v) NaCl (optimum, 1 %, w/v). The genome of strain CC-MHH1044T consisted of 8.5 Mb and the genomic DNA G+C content was 58.5 mol%. Comparison of the 16S rRNA gene sequences showed that CC-MHH1044T belonged to the genus Cohnella and showed a close relationship with the type strains of Cohnella damuensis (96.2 %) and Cohnella panacarvi (95.9 %), and lower sequence similarity to other species. Average nucleotide identity values calculated from whole-genome sequencing data proved that CC-MHH1044T represents a distinct Cohnella species. The dominant cellular fatty acids (>5 %) included iso-C14 : 0(7.4 %), iso-C15 : 0 (6.4 %), anteiso-C15 : 0(40.3 %), C16 : 0 (6.6 %) and iso-C16 : 0 (27.0 %). The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, four unidentified aminophospholipids, one unidentified phospholipid and glycolipid. The major polyamine was spermidine. The predominant isoprenoid quinone was menaqinone 7 (MK-7). Based on its distinct phylogenetic, phenotypic and chemotaxonomic traits, together with results of comparative 16S rRNA gene sequence, average nucleotide identity and digital DNA–DNA hybridization analyses, we conclude that strain CC-MHH1044T represents a novel member of the genus Cohnella , for which the name Cohnella fermenti sp. nov. is proposed. The type strain is CC-MHH1044T (=BCRC 81147T=JCM 32834T).

scholarly journals A genus definition for Bacteria and Archaea based on genome relatedness and taxonomic affiliation

2018 ◽  
Author(s):  
R.A. Barco ◽  
G.M. Garrity ◽  
J.J. Scott ◽  
J.P. Amend ◽  
K.H. Nealson ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Type Species ◽  
Rrna Gene ◽  
Human Pathogens ◽  
Genome Level ◽  
Taxonomic Affiliation ◽  
Close Relatives ◽  
Type Strains ◽  
The 16S Rrna Gene

AbstractGenus assignment is fundamental in the characterization of microbes, yet there is currently no unambiguous way to demarcate genera solely using standard genomic relatedness indices. Here, we propose an approach to demarcate genera that relies on the combined use of the average nucleotide identity, genome alignment fraction, and the distinction between type species and non-type species. More than 750 genomes representing type strains of species from 10 different phyla, and 19 different taxonomic orders/families in Gram-positive/negative, bacterial and archaeal lineages were tested. Overall, all 19 analyzed taxa conserved significant genomic differences between members of a genus and type species of other genera in the same taxonomic family. Bacillus, Flavobacterium, Hydrogenovibrio, Lactococcus, Methanosarcina, Thiomicrorhabdus, Thiomicrospira, Shewanella, and Vibrio are discussed in detail. Less than 1% of the type strains analyzed need reclassification, highlighting that the adoption of the 16S rRNA gene as a taxonomic marker has provided consistency to the classification of microorganisms in recent decades. One exception to this is the genus Bacillus with 61% of type strains needing reclassification, including the human pathogens B. cereus and B. anthracis. The results provide a first line of evidence that the combination of genomic indices provides appropriate resolution to effectively demarcate genera within the current taxonomic framework that is based on the 16S rRNA gene. We also identify the emergence of natural breakpoints at the genome level that can further help in the circumscription of genera. Altogether, these results show that a distinct difference between distant relatives and close relatives at the genome level (i.e., genomic coherence) is an emergent property of genera in Bacteria and Archaea.

scholarly journals Streptomyces apocyni sp. nov., an endogenous actinomycete isolated from Apocynum venetum

2020 ◽  
Vol 70 (9) ◽  
pp. 4883-4889 ◽  
Author(s):  
Wen-Xiang Liu ◽  
Li-Ran Ma ◽  
Zhan-Feng Xia ◽  
Hong Zeng ◽  
Xiao-Xia Luo ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Type Species ◽  
Nucleotide Identity ◽  
Rrna Gene ◽  
Average Nucleotide Identity ◽  
Content Type ◽  
Link Type ◽  
Apocynum Venetum ◽  
Taxonomic Approach

A novel actinomycete, designated strain TRM 66233T, was isolated from Apocynum venetum L. collected from the Xinjiang Uygur Autonomous Region of China and characterized using a polyphasic taxonomic approach. Phylogenetic analysis based on 16S rRNA gene sequences affiliated strain TRM 66233T with the genus Streptomyces . Strain TRM 66233T showed a high similarity value to Streptomyces bikiniensis NRRL B-1049T (98.07 %) based on the 16S rRNA gene phylogenetic tree. The whole-cell sugar pattern of TRM 66233T consisted of glucose, galactose, mannose and ribose. The predominant menaquinones were MK-9(H2), MK-9(H6), MK-9(H8) and MK-9(H10). The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and four unidentified lipids. The major fatty acids were iso-C15 : 0, anteiso-C15 : 0, iso-C16 : 0, C16 : 0 and iso-C17 : 0. The G+C content of the DNA was 70.35 mol%. The DNA–DNA relatedness and average nucleotide identity values as well as evolutionary distances based on multilocus (atpD, gyrB, recA, rpoB and trpB) sequences between strain TRM 66233T and closely related type strains were significantly lower than the recommended threshold values. The whole-genome average nucleotide identity and digital DNA–DNA hybridization values between strain TRM 66233T and S. bikiniensis NRRL B-1049T were 78.86 and 23.2 %, respectively. On the basis of evidence from this polyphasic study, strain TRM 66233T should represent a novel species of the genus Streptomyces , for which the name Streptomyces apocyni sp. nov. is proposed. The type strain is TRM 66233T (=CCTCC AA 2019056T=LMG 31559T).

Kribbella albertanoniae sp. nov., isolated from a Roman catacomb, and emended description of the genus Kribbella

2013 ◽  
Vol 63 (Pt_10) ◽  
pp. 3591-3596 ◽  
Author(s):  
Gareth J. Everest ◽  
Sarah M. Curtis ◽  
Filomena De Leo ◽  
Clara Urzì ◽  
Paul R. Meyers
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Type Species ◽  
Rrna Gene ◽  
Content Type ◽  
Distance Analysis ◽  
Link Type ◽  
Genetic Distance Analysis ◽  
Type Strains ◽  
The 16S Rrna Gene

A novel actinobacterium, strain BC640T, was isolated from a biofilm sample collected in 2009 in the Saint Callistus Roman catacombs. Analysis of the 16S rRNA gene sequence showed that the strain belonged to the genus Kribbella . Phylogenetic analysis using the 16S rRNA gene and concatenated gyrB, rpoB, relA, recA and atpD gene sequences showed that strain BC640T was most closely related to the type strains of Kribbella yunnanensis and Kribbella sandramycini . Based on gyrB genetic distance analysis, strain BC640T was shown to be distinct from all Kribbella type strains. DNA–DNA hybridization experiments confirmed that strain BC640T represents a genomic species distinct from its closest phylogenetic relatives, K. yunnanensis DSM 15499T (53.5±7.8 % DNA relatedness) and K. sandramycini DSM 15626T (33.5±5.0 %). Physiological comparisons further showed that strain BC640T is phenotypically distinct from the type strains of K. yunnanensis and K. sandramycini . Strain BC640T ( = DSM 26744T = NRRL B-24917T) is thus presented as the type strain of a novel species, for which the name Kribbella albertanoniae sp. nov. is proposed.

scholarly journals Psychrobacter ciconiae sp. nov., isolated from white storks (Ciconia ciconia)

2015 ◽  
Vol 65 (Pt_3) ◽  
pp. 772-777 ◽  
Author(s):  
Peter Kämpfer ◽  
Leszek Jerzak ◽  
Gottfried Wilharm ◽  
Jan Golke ◽  
Hans-Jürgen Busse ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Type Species ◽  
Rrna Gene ◽  
Content Type ◽  
Link Type ◽  
White Storks ◽  
Type Strains ◽  
The 16S Rrna Gene ◽  
Sequence Similarities

Five beige bacterial strains (176/10T, 178/10, 182/10, 185/7 and 193/8) were isolated from white storks in Poland and found to share identical 16S rRNA gene sequences; they were also investigated in a polyphasic taxonomic study. The cells of all isolates were rod-shaped and Gram-stain-negative. A comparison of the 16S rRNA gene sequences of these organisms with the sequences of the type strains of the most closely related species of the genus Psychrobacter showed highest sequence similarities to the type strains of Psychrobacter pulmonis and Psychrobacter faecalis (both 97.1 %). The 16S rRNA gene sequence similarities to all other species of the genus Psychrobacter were below 96.3 %. All five isolates showed an identical profile of physiological reactions and almost identical fatty acid profiles consisting of mainly C18 : 1ω9c, but also C12 : 0 3-OH as a characteristic hydroxylated fatty acid. A quinone system with mainly ubiquinone Q-8 was detected and the polar lipid profile of the type strain, 176/10T, was mainly composed of phosphatidylethanolamine, phosphatidylglycerol, phosphatidylserine and diphosphatidylglycerol, plus some hitherto uncharacterized phospholipids and one aminolipid. The major polyamines were spermidine and putrescine. DNA–DNA hybridizations between 176/10T and the type strains of P. pulmonis and P. faecialis resulted in relatedness values below 70 %. These results indicate that the strains represent a novel species, for which the name Psychrobacter ciconiae sp. nov. (type strain 176/10T = CIP 110777T = LMG 28175T = CCM 8519T) is proposed.

Pseudomonas carbonaria sp. nov., isolated from charcoal

2021 ◽  
Vol 71 (4) ◽  
Author(s):  
Peter Kämpfer ◽  
S. P. Glaeser ◽  
John A. McInroy ◽  
Dominique Clermont ◽  
Alexis Criscuolo ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Type Species ◽  
Phylogenetic Analyses ◽  
Rrna Gene ◽  
Biochemical Tests ◽  
Content Type ◽  
Link Type ◽  
Type Strains ◽  
The 16S Rrna Gene

A beige-pigmented, oxidase-positive bacterial isolate, Wesi-4T, isolated from charcoal in 2012, was examined in detail by applying a polyphasic taxonomic approach. Cells of the isolates were rod shaped and Gram-stain negative. Examination of the 16S rRNA gene sequence of the isolate revealed highest sequence similarities to the type strains of Pseudomonas matsuisoli and Pseudomonas nosocomialis (both 97.3 %). Phylogenetic analyses on the basis of the 16S rRNA gene sequences indicated a separate position of Wesi-4T, which was confirmed by multilocus sequence analyses (MLSA) based on the three loci gyrB, rpoB and rpoD and a core genome-based phylogenetic tree. Genome sequence based comparison of Wesi-4T and the type strains of P. matsuisoli and P. nosocomialis yielded average nucleotide identity values <95 % and in silico DNA-DNA hybridization values <70 %, respectively. The polyamine pattern contains the major amines putrescine, cadaverine and spermidine. The quinone system contains predominantly ubiquinone Q-9 and in the polar lipid profile diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine are the major lipids. The fatty acid contains predominantly C16 : 0, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and summed feature 8 (C18 : 1ω7c and/or C18 : 1 ω6c). In addition, physiological and biochemical tests revealed a clear phenotypic difference from P. matsuisoli . These cumulative data indicate that the isolate represents a novel species of the genus Pseudomonas for which the name Pseudomonas carbonaria sp. nov. is proposed with Wesi-4T (=DSM 110367T=CIP 111764T=CCM 9017T) as the type strain.

Reclassification of Parvularcula flava as Aquisalinus luteolus nom. nov. and emended description of the genus Aquisalinus

2021 ◽  
Vol 71 (10) ◽  
Author(s):  
Jun-Jie Ying ◽  
Zhi-Cheng Wu ◽  
Yuan-Chun Fang ◽  
Lin Xu ◽  
Cong Sun
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Type Species ◽  
Comparative Genomic ◽  
Rrna Gene ◽  
Gene Sequences ◽  
16S Rrna Gene Sequences ◽  
Content Type ◽  
Link Type ◽  
Type Strains

Parvularcula flava was proposed as a novel member of genus Parvularcula in 2016. Some time earlier, Aquisalinus flavus has been proposed as a novel species of a novel genus named Aquisalinus . When comparing the 16S rRNA gene sequences of type strains P. flava NH6-79T and A. flavus D11M-2T, they showed 97.9 % sequence identity, much higher than the sequence identities 92.7–94.3 % between P. flava NH6-79T and type strains in the genus Parvularcula , indicating that the later proposed novel taxon Parvularcula flava need reclassification. The phylogenetic trees based on 16S rRNA gene sequences and genome sequences both showed that P. flava NH6-79T and A. flavus D11M-2T formed a separated branch away from strains in the genera Parvularcula , Marinicaulis and Amphiplicatus . The average amino acid identity and average nucleotide identity values of P. flava NH6-79T and A. flavus D11M-2T were 87.9 and 85.0 %, respectively, much higher than the values between P. flava NH6-79T and other closely related type strains (54.3 %–58.1 % and 68.6–70.4 %, respectively). P. flava NH6-79T and A. flavus D11M-2T also contained summed feature 8 (C18 : 1  ω6c and/or C18 : 1  ω7c) and C16 : 0 as major fatty acids, distinguishing them from other closely related taxa. Based on the results of the phylogenetic, comparative genomic and phenotypic analyses, Parvularcula flava should be reclassified as Aquisalinus luteolus nom. nov. and the description of genus Aquisalinus is emended.

Namhaeicola litoreus gen. nov., sp. nov., a member of the family Flavobacteriaceae isolated from seawater

2012 ◽  
Vol 62 (Pt_9) ◽  
pp. 2163-2168 ◽  
Author(s):  
Yong-Taek Jung ◽  
Ji-Hoon Kim ◽  
So-Jung Kang ◽  
Tae-Kwang Oh ◽  
Jung-Hoon Yoon
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Type Species ◽  
Sequence Similarity ◽  
Phylogenetic Analyses ◽  
Rrna Gene ◽  
Content Type ◽  
Link Type ◽  
The Family ◽  
Type Strains

A Gram-staining-negative, non-flagellated, non-gliding and pleomorphic bacterial strain, designated DPG-25T, was isolated from seawater in a seaweed farm in the South Sea in Korea and its taxonomic position was investigated by using a polyphasic approach. Strain DPG-25T grew optimally at 25 °C, at pH 7.0–7.5 and in the presence of 2 % (w/v) NaCl. Flexirubin-type pigments were not produced. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain DPG-25T formed a cluster with the type strains of Actibacter sediminis , Aestuariicola saemankumensis and Lutimonas vermicola . Strain DPG-25T exhibited 16S rRNA gene sequence similarity values of 95.3, 93.1 and 93.6 % to the type strains of Actibacter sediminis , Aestuariicola saemankumensis and L. vermicola , respectively. Strain DPG-25T contained MK-6 as the predominant menaquinone and iso-C15 : 0 and iso-C17 : 0 3-OH as the major fatty acids. The major polar lipids detected in strain DPG-25T were phosphatidylethanolamine and one unidentified lipid. The DNA G+C content was 39.9 mol%. Differential phenotypic properties and the phylogenetic distinctiveness of strain DPG-25T demonstrated that this strain is distinguishable from Actibacter sediminis , Aestuariicola saemankumensis and L. vermicola . On the basis of the data presented here, strain DPG-25T represents a novel species in a novel genus of the family Flavobacteriaceae , for which the name Namhaeicola litoreus gen. nov., sp. nov. is proposed. The type strain of Namhaeicola litoreus is DPG-25T ( = KCTC 23702T  = CCUG 61485T).

scholarly journals Erythrobacter pelagi sp. nov., a member of the family Erythrobacteraceae isolated from the Red Sea

2012 ◽  
Vol 62 (Pt_6) ◽  
pp. 1348-1353 ◽  
Author(s):  
Hui-xian Wu ◽  
Pok Yui Lai ◽  
On On Lee ◽  
Xiao-jian Zhou ◽  
Li Miao ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Red Sea ◽  
Type Species ◽  
Sequence Similarity ◽  
Rrna Gene ◽  
Phenotypic Properties ◽  
Content Type ◽  
Link Type ◽  
Type Strains

A novel Gram-negative, aerobic, catalase- and oxidase-positive, non-sporulating, non-motile, rod-shaped bacterium, designated strain UST081027-248T, was isolated from seawater of the Red Sea. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain UST081027-248T fell within the genus Erythrobacter . Levels of 16S rRNA gene sequence similarity between the novel strain and the type strains of Erythrobacter species ranged from 95.3 % (with Erythrobacter gangjinensis ) to 98.2 % (with Erythrobacter citreus ). However, levels of DNA–DNA relatedness between strain UST081027-248T and the type strains of closely related species were below 70 %. Optimal growth of the isolate occurred in the presence of 2.0 % NaCl, at pH 8.0–9.0 and at 28–36 °C. The isolate did not produce bacteriochlorophyll a. The predominant cellular fatty acids were C17 : 1ω6c, summed feature 8 (C18 : 1ω6c and/or C18 : 1ω7c) and C15 : 0 2-OH. The genomic DNA G+C content of strain UST081027-248T was 60.4 mol%. Phenotypic properties and phylogenetic distinctiveness clearly indicated that strain UST081027-248T represents a novel species of the genus Erythrobacter , for which the name Erythrobacter pelagi sp. nov. is proposed. The type strain is UST081027-248T ( = JCM 17468T = NRRL 59511T).

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