scholarly journals Taxonomy annotation and guide tree errors in 16S rRNA databases

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5030 ◽  
Author(s):  
Robert Edgar
Keyword(s):  
16S Rrna ◽  
Ribosomal Rna ◽  
Error Rate ◽  
Rrna Gene ◽  
Training Set ◽  
Annotation Error ◽  
Order And Type ◽  
Comparable Quality ◽  
Type Strains ◽  
Guide Trees

Sequencing of the 16S ribosomal RNA (rRNA) gene is widely used to survey microbial communities. Specialized 16S rRNA databases have been developed to support this approach including Greengenes, RDP and SILVA. Most taxonomy annotations in these databases are predictions from sequence rather than authoritative assignments based on studies of type strains or isolates. In this work, I investigated the taxonomy annotations and guide trees provided by these databases. Using a blinded test, I estimated that the annotation error rate of the RDP database is ∼10%. The branching orders of the Greengenes and SILVA guide trees were found to disagree at comparable rates with each other and with taxonomy annotations according to the training set (authoritative reference) provided by RDP, indicating that the trees have comparable quality. Pervasive conflicts between tree branching order and type strain taxonomies strongly suggest that the guide trees are unreliable guides to phylogeny. I found 249,490 identical sequences with conflicting annotations in SILVA v128 and Greengenes v13.5 at ranks up to phylum (7,804 conflicts), indicating that the annotation error rate in these databases is ∼17%.

scholarly journals Taxonomy annotation errors in 16S rRNA and fungal ITS sequence databases

2018 ◽  
Author(s):  
Robert C. Edgar
Keyword(s):  
Ribosomal Rna ◽  
Error Rate ◽  
Its Region ◽  
Error Rates ◽  
Rrna Gene ◽  
Branching Order ◽  
Annotation Error ◽  
Sequence Databases ◽  
Type Strains ◽  
Annotation Errors

AbstractSequencing of the 16S ribosomal RNA (rRNA) gene and the fungal Internal Transcribed Spacer (ITS) region is widely used to survey microbial communities. Specialized ribosomal sequence databases have been developed to support this approach including Greengenes, SILVA and RDP. Most taxonomy annotations in these databases are predictions from sequence rather than authoritative assignments based on studies of type strains or isolates. Here, I investigate the error rates of taxonomy annotations in these databases. I found 253,485 sequences with conflicting annotations in SILVA v128 and Greengenes v13.5 at ranks up to phylum (9,644 conflicts), indicating that the annotation error rate in these databases is ~15%. I found that 34% of non-singleton genera have overlapping subtrees in the Greengenes tree from 2001 according to the RDP taxonomy, most of which are probably due to branching order errors in the Greengenes tree, which is therefore an unreliable guide to phylogeny. Using a blinded test, I estimated that the annotation error rate of the RDP database is ~10%.

scholarly journals Sphingobacterium yanglingense sp. nov., isolated from the nodule surface of soybean

2014 ◽  
Vol 64 (Pt_11) ◽  
pp. 3862-3866 ◽  
Author(s):  
Shi Peng ◽  
Dong Dan Hong ◽  
Yang Bing Xin ◽  
Li Ming Jun ◽  
Wei Ge Hong
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Polar Lipids ◽  
Rrna Gene ◽  
Content Type ◽  
Link Type ◽  
Gram Staining ◽  
Physiological And Biochemical Characteristics ◽  
Gene Sequence Analysis ◽  
Type Strains

A Gram-staining-negative, non-motile, catalase- and oxidase-positive strain, designated CCNWSP36-1T, was isolated from the nodule surface of soybean [Glycine max (L.) Merrill] cultivar Zhonghuang 13. The 16S rRNA gene sequence analysis clearly showed that the isolate represented a member of the genus Sphingobacterium . On the basis of pairwise comparisons of 16S rRNA gene sequences, strain CCNWSP36-1T showed 96.8 % similarity to Sphingobacterium nematocida CCTCC AB 2010390T and less than 95.2 % similarity to other members of the genus Sphingobacterium . Growth of strain CCNWSP36-1T occurred at 10–40 °C and at pH 5.0–9.0. The NaCl range (w/v) for growth was 0–4 %. The predominant isoprenoid quinone was MK-7. The polar lipids were phosphatidylethanolamine and several unidentified polar lipids. Sphingolipid was present. The major fatty acids were iso-C15 : 0 and summed feature 3 (comprising C16 : 1ω6c and/or C16 : 1ω7c). The G+C content of the genomic DNA was 41.1 mol%. As the physiological and biochemical characteristics of strain CCNWSP36-1T and the type strains of its closest phylogenetic neighbours showed clear differences, a novel species, Sphingobacterium yanglingense, is proposed. The type strain is CCNWSP36-1T ( = ACCC 19328T = JCM 30166T).

scholarly journals Nocardioides panacihumi sp. nov., isolated from soil of a ginseng field

2007 ◽  
Vol 57 (9) ◽  
pp. 2143-2146 ◽  
Author(s):  
Dong-Shan An ◽  
Wan-Taek Im ◽  
Sung-Taik Lee ◽  
Min-Ho Yoon
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Major Fatty Acid ◽  
Rrna Gene ◽  
Strictly Aerobic ◽  
Biochemical Tests ◽  
Phenotypic Differentiation ◽  
The Family ◽  
Established Species ◽  
Type Strains

A novel bacterial strain designated Gsoil 616T was isolated from a soil sample of a ginseng field in Pocheon province (South Korea) and was characterized taxonomically by using a polyphasic approach. The isolate was Gram-positive, strictly aerobic, non-motile, non-spore-forming and rod- or coccoid-shaped. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolate belongs to the genus Nocardioides in the family Nocardioidaceae but was clearly separated from established species of this genus. The 16S rRNA gene sequence similarities between strain Gsoil 616T and the type strains of Nocardioides species with validly published names ranged from 91.8 to 96.1 %. The G+C content of the genomic DNA was 73 mol%. Phenotypic and chemotaxonomic data [major menaquinone MK-8(H4) and major fatty acid iso-C16 : 0] supported the affiliation of strain Gsoil 616T to the genus Nocardioides. However, the results of physiological and biochemical tests allowed phenotypic differentiation of the isolate from other Nocardioides species. Therefore, strain Gsoil 616T represented a novel species within the genus Nocardioides, for which the name Nocardioides panacihumi sp. nov. is proposed. The type strain is Gsoil 616T (=KCTC 19187T =DSM 18660T).

scholarly journals Marinobacter flavimaris sp. nov. and Marinobacter daepoensis sp. nov., slightly halophilic organisms isolated from sea water of the Yellow Sea in Korea

2004 ◽  
Vol 54 (5) ◽  
pp. 1799-1803 ◽  
Author(s):  
Jung-Hoon Yoon ◽  
Soo-Hwan Yeo ◽  
In-Gi Kim ◽  
Tae-Kwang Oh
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Gene Sequence ◽  
Sea Water ◽  
Sequence Similarity ◽  
The Yellow Sea ◽  
Rrna Gene ◽  
Rrna Gene Sequence ◽  
16S Rrna Gene Sequences ◽  
Type Strains

Two Gram-negative, motile, non-spore-forming and slightly halophilic rods (strains SW-145T and SW-156T) were isolated from sea water of the Yellow Sea in Korea. Strains SW-145T and SW-156T grew optimally at 37 and 30–37 °C, respectively, and in the presence of 2–6 % (w/v) NaCl. Strains SW-145T and SW-156T were chemotaxonomically characterized as having ubiquinone-9 as the predominant respiratory lipoquinone and C16 : 0, C18 : 1 ω9c, C16 : 1 ω9c and C12 : 0 3-OH as the major fatty acids. The DNA G+C contents of strains SW-145T and SW-156T were 58 and 57 mol%, respectively. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains SW-145T and SW-156T fell within the evolutionary radiation enclosed by the genus Marinobacter. The 16S rRNA gene sequences of strains SW-145T and SW-156T were 94·8 % similar. Strains SW-145T and SW-156T exhibited 16S rRNA gene sequence similarity levels of 94·3–98·1 and 95·4–97·7 %, respectively, with respect to the type strains of all Marinobacter species. Levels of DNA–DNA relatedness, together with 16S rRNA gene sequence similarity values, indicated that strains SW-145T and SW-156T are members of two species that are distinct from seven Marinobacter species with validly published names. On the basis of phenotypic properties and phylogenetic and genotypic distinctiveness, strains SW-145T (=KCTC 12185T=DSM 16070T) and SW-156T (=KCTC 12184T=DSM 16072T) should be placed in the genus Marinobacter as the type strains of two distinct novel species, for which the names Marinobacter flavimaris sp. nov. and Marinobacter daepoensis sp. nov. are proposed.

scholarly journals Planococcus salinarum sp. nov., isolated from a marine solar saltern, and emended description of the genus Planococcus

2010 ◽  
Vol 60 (4) ◽  
pp. 754-758 ◽  
Author(s):  
Jung-Hoon Yoon ◽  
So-Jung Kang ◽  
Soo-Young Lee ◽  
Ki-Hoon Oh ◽  
Tae-Kwang Oh
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Gene Sequence ◽  
16S Rrna Gene Sequence ◽  
Rrna Gene ◽  
Solar Saltern ◽  
Rrna Gene Sequence ◽  
Marine Solar Saltern ◽  
Emended Description ◽  
Type Strains

A Gram-positive, non-motile and coccoid-, short rod- or rod-shaped bacterial strain, ISL-16T, was isolated from a marine solar saltern in Korea and its taxonomic position was investigated using a polyphasic taxonomic approach. Strain ISL-16T grew optimally at pH 7.0–8.0, at 30 °C and in the presence of 2 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain ISL-16T joined the cluster comprising species of the genus Planococcus. Its 16S rRNA gene sequence contained the same signature nucleotides as those defined for the genus Planococcus. Strain ISL-16T exhibited 16S rRNA gene sequence similarity values of 96.9–98.2 % to the type strains of species of the genus Planococcus. Strain ISL-16T contained MK-8 and MK-7 as the predominant menaquinones and anteiso-C15 : 0, C16 : 1 ω7c alcohol and anteiso-C17 : 0 as the major fatty acids. The DNA G+C content was 48.3 mol%. DNA–DNA relatedness values between strain ISL-16T and the type strains of species of the genus Planococcus were 15–28 %. Differential phenotypic properties, together with its phylogenetic and genetic distinctiveness, enabled strain ISL-16T to be differentiated from recognized species of the genus Planococcus. On the basis of the data presented, strain ISL-16T is considered to represent a novel species of the genus Planococcus, for which the name Planococcus salinarum sp. nov. is proposed. The type strain is ISL-16T (=KCTC 13584T=CCUG 57753T). An emended description of the genus Planococcus is also given.

scholarly journals Chitinophaga longshanensis sp. nov., a mineral-weathering bacterium isolated from weathered rock

2015 ◽  
Vol 65 (Pt_2) ◽  
pp. 418-423 ◽  
Author(s):  
Shan Gao ◽  
Wen-Bin Zhang ◽  
Xia-Fang Sheng ◽  
Lin-Yan He ◽  
Zhi Huang
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Sequence Similarity ◽  
Mineral Weathering ◽  
Rrna Gene ◽  
Phenotypic Properties ◽  
Content Type ◽  
Weathered Rock ◽  
Link Type ◽  
Type Strains

A Gram-stain-negative, aerobic, yellow-pigmented, non-motile, non-spore-forming, rod-shaped bacterial strain, Z29T, was isolated from the surface of weathered rock (potassic trachyte) from Nanjing, Jiangsu Province, PR China. Phylogenetic analysis based on 16S rRNA gene sequences suggested that strain Z29T belongs to the genus Chitinophaga in the family Chitinophagaceae . Levels of 16S rRNA gene sequence similarity between strain Z29T and the type strains of recognized species of the genus Chitinophaga ranged from 92.7 to 98.2 %. The main fatty acids of strain Z29T were iso-C15 : 0, C16 : 1ω5c and iso-C17 : 0 3-OH. It also contained menaquinone 7 (MK-7) as the respiratory quinone and homospermidine as the main polyamine. The polar lipid profile contained phosphatidylethanolamine, unknown aminolipids, unknown phospholipids and unknown lipids. The total DNA G+C content of strain Z29T was 51.3 mol%. Phenotypic properties and chemotaxonomic data supported the affiliation of strain Z29T with the genus Chitinophaga . The low level of DNA–DNA relatedness (ranging from 14.6 to 29.8 %) to the type strains of other species of the genus Chitinophaga and differential phenotypic properties demonstrated that strain Z29T represents a novel species of the genus Chitinophaga , for which the name Chitinophaga longshanensis sp. nov. is proposed. The type strain is Z29T ( = CCTCC AB 2014066T = LMG 28237T).

Kordia aestuariivivens sp. nov. and Olleya sediminilitoris sp. nov., isolated from a tidal flat

2021 ◽  
Vol 71 (6) ◽  
Author(s):  
Sooyeon Park ◽  
Jung-Sook Lee ◽  
Wonyong Kim ◽  
Jung-Hoon Yoon
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Tidal Flat ◽  
Genomic Sequences ◽  
Rrna Gene ◽  
Phenotypic Properties ◽  
Content Type ◽  
Link Type ◽  
The Family ◽  
Type Strains

Two Gram-stain-negative and non-flagellated bacteria, YSTF-M3T and YSTF-M6T, were isolated from a tidal flat from Yellow Sea, Republic of Korea, and subjected to a polyphasic taxonomic study. Neighbour-joining phylogenetic tree of 16S rRNA gene sequences showed that strains YSTF-M3T and YSTF-M6T belong to the genera Kordia and Olleya of the family Flavobacteriaceae , respectively. The 16S rRNA gene sequence similarities between strain YSTF-M3T and the type strains of Kordia species and between strain YSTF-M6T and the type strains of Olleya species were 94.1–98.4 and 97.3–98.3 %, respectively. The ANI and dDDH values between genomic sequences of strain YSTF-M3T and the type strains of five Kordia species and between those of strain YSTF-M6T and the type strains of three Olleya species were in ranges of 77.0–83.2 and 20.7–27.1 % and 79.4–81.5 and 22.3–23.9 %, respectively. The DNA G+C contents of strain YSTF-M3T and YSTF-M6T from genomic sequences were 34.1 and 31.1 %, respectively. Both strains contained MK-6 as predominant menaquinone and phosphatidylethanolamine as only major phospholipid identified. Differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that strains YSTF-M3T and YSTF-M6T are separated from recognized species of the genera Kordia and Olleya , respectively. On the basis of the data presented, strains YSTF-M3T (=KACC 21639T=NBRC 114499T) and YSTF-M6T (=KACC 21640T=NBRC 114500T) are considered to represent novel species of the genera Kordia and Olleya , respectively, for which the names Kordia aestuariivivens sp. nov. and Olleya sediminilitoris sp. nov. are proposed.

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.

scholarly journals Pedobacter boryungensis sp. nov., isolated from soil

2012 ◽  
Vol 62 (1) ◽  
pp. 13-17 ◽  
Author(s):  
Yong-Taek Jung ◽  
Soo-Young Lee ◽  
Won-Chan Choi ◽  
Tae-Kwang Oh ◽  
Jung-Hoon Yoon
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Gene Sequence ◽  
Novel Species ◽  
Sequence Similarity ◽  
Rrna Gene ◽  
Rrna Gene Sequence ◽  
16S Rrna Gene Sequences ◽  
Phenotypic Properties ◽  
Type Strains

A Gram-negative, non-sporulating, non-flagellated rod, designated BR-9T, was isolated from soil collected on the Korean peninsula. Strain BR-9T grew optimally at pH 6.0–7.0, at 30 °C and in the absence of NaCl. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain BR-9T belonged to the genus Pedobacter and clustered with Pedobacter insulae DS-139T and Pedobacter koreensis WPCB189T. Strain BR-9T exhibited 98.2 and 97.5 % 16S rRNA gene sequence similarity with P. insulae DS-139T and P. koreensis WPCB189T, respectively, and <96.7 % sequence similarity with the type strains of other species in the genus Pedobacter. Strain BR-9T contained MK-7 as the predominant menaquinone and iso-C15 : 0 and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH) as the major fatty acids. The DNA G+C content of strain BR-9T was 38.5 mol%. DNA–DNA relatedness between strain BR-9T and P. insulae DS-139T and P. koreensis KCTC 12536T was 3.4–4.2 %, which indicated that the isolate was genetically distinct from these type strains. Strain BR-9T was also distinguishable by differences in phenotypic properties. On the basis of the data presented, strain BR-9T is considered to represent a novel species of the genus Pedobacter, for which the name Pedobacter boryungensis sp. nov. is proposed. The type strain is BR-9T ( = KCTC 23344T  = CCUG 60024T).

scholarly journals Flavobacterium terrigena sp. nov., isolated from soil

2007 ◽  
Vol 57 (5) ◽  
pp. 947-950 ◽  
Author(s):  
Jung-Hoon Yoon ◽  
So-Jung Kang ◽  
Jung-Sook Lee ◽  
Tae-Kwang Oh
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Gene Sequence ◽  
Novel Species ◽  
Sequence Similarity ◽  
Rrna Gene ◽  
Rrna Gene Sequence ◽  
16S Rrna Gene Sequences ◽  
Phenotypic Characteristics ◽  
Type Strains

A Gram-negative, rod-shaped, Flavobacterium-like bacterial strain, DS-20T, was isolated from soil from the island of Dokdo, Korea, and subjected to a polyphasic taxonomic study. Strain DS-20T grew optimally at pH 6.5–7.0 and 25 °C. It contained MK-6 as the predominant menaquinone and iso-C15 : 0, iso-C17 : 0 3-OH and iso-C17 : 1 ω9c as the major fatty acids. The DNA G+C content was 38.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain DS-20T belonged to the genus Flavobacterium. Levels of 16S rRNA gene sequence similarity between strain DS-20T and the type strains of recognized Flavobacterium species were below 94.9 %. Strain DS-20T differed from phylogenetically related Flavobacterium species in several phenotypic characteristics. On the basis of its phenotypic and phylogenetic distinctiveness, strain DS-20T was classified in the genus Flavobacterium as representing a novel species, for which the name Flavobacterium terrigena sp. nov. is proposed. The type strain is DS-20T (=KCTC 12761T=DSM 17934T).

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