scholarly journals Phylogenetic analysis and delineation of phytoplasmas based on secY gene sequences

2010 ◽  
Vol 60 (12) ◽  
pp. 2887-2897 ◽  
Author(s):  
I.-M. Lee ◽  
K. D. Bottner-Parker ◽  
Y. Zhao ◽  
R. E. Davis ◽  
N. A. Harrison

The secY gene sequence is more variable than that of the 16S rRNA gene. Comparative phylogenetic analyses with 16S rRNA and secY gene sequences from 80 and 83 phytoplasma strains, respectively, were performed to assess the efficacy of these sequences for delineating phytoplasma strains within each 16Sr group. The phylogenetic interrelatedness among phytoplasma taxa inferred by secY gene-based phylogeny was nearly congruent with that inferred by 16S rRNA gene-based phylogeny. Phylogenetic analysis based on the secY gene permitted finer differentiation of phytoplasma strains, however. The secY gene-based phylogeny not only readily resolved 16Sr subgroups within a given 16Sr group, but also delineated distinct lineages irresolvable by 16S rRNA gene-based phylogeny. Such high resolving power makes the secY gene a more useful genetic marker than the 16S rRNA gene for finer differentiation of closely related phytoplasma strains based on RFLP analysis with selected restriction enzymes. Such strains were readily identified by collective secY RFLP patterns. The genetic interrelationships among these strains were determined by pattern similarity coefficients, which coincided with delineations by phylogenetic analysis. This study also revealed two heterogeneous spc operons present in the phytoplasma clade. This latter finding may have significant implications for phytoplasma evolution.

2014 ◽  
Vol 64 (Pt_6) ◽  
pp. 1890-1899 ◽  
Author(s):  
Nigel A. Harrison ◽  
Robert E. Davis ◽  
Carlos Oropeza ◽  
Ericka E. Helmick ◽  
María Narváez ◽  
...  

In this study, the taxonomic position and group classification of the phytoplasma associated with a lethal yellowing-type disease (LYD) of coconut (Cocos nucifera L.) in Mozambique were addressed. Pairwise similarity values based on alignment of nearly full-length 16S rRNA gene sequences (1530 bp) revealed that the Mozambique coconut phytoplasma (LYDM) shared 100 % identity with a comparable sequence derived from a phytoplasma strain (LDN) responsible for Awka wilt disease of coconut in Nigeria, and shared 99.0–99.6 % identity with 16S rRNA gene sequences from strains associated with Cape St Paul wilt (CSPW) disease of coconut in Ghana and Côte d’Ivoire. Similarity scores further determined that the 16S rRNA gene of the LYDM phytoplasma shared <97.5 % sequence identity with all previously described members of ‘Candidatus Phytoplasma ’. The presence of unique regions in the 16S rRNA gene sequence distinguished the LYDM phytoplasma from all currently described members of ‘Candidatus Phytoplasma ’, justifying its recognition as the reference strain of a novel taxon, ‘Candidatus Phytoplasma palmicola’. Virtual RFLP profiles of the F2n/R2 portion (1251 bp) of the 16S rRNA gene and pattern similarity coefficients delineated coconut LYDM phytoplasma strains from Mozambique as novel members of established group 16SrXXII, subgroup A (16SrXXII-A). Similarity coefficients of 0.97 were obtained for comparisons between subgroup 16SrXXII-A strains and CSPW phytoplasmas from Ghana and Côte d’Ivoire. On this basis, the CSPW phytoplasma strains were designated members of a novel subgroup, 16SrXXII-B.


2010 ◽  
Vol 60 (11) ◽  
pp. 2552-2556 ◽  
Author(s):  
Ping Fa Zhou ◽  
Wei Min Chen ◽  
Ge Hong Wei

Previously, five rhizobial strains isolated from root nodules of Robinia pseudoacacia were assigned to the same genospecies on the basis of identical 16S rRNA gene sequences and phylogenetic analyses of the nodA, nodC and nifH genes, in which the five isolates formed a well-supported group that excluded other sequences found in public databases. In this study, the 16S rRNA gene sequence similarities between the isolates and Mesorhizobium mediterraneum UPM-Ca36T and Mesorhizobium temperatum SDW018T were 99.5 and 99.6 %, respectively. The five isolates were also different from defined Mesorhizobium species using ERIC fingerprint profiles and they formed a novel Mesorhizobium lineage in phylogenetic analyses of recA and atpD gene sequences. DNA–DNA relatedness values between the representative strain, CCNWYC 115T, and type strains of defined Mesorhizobium species were found to be lower than 47.5 %. These results indicated that the isolates represented a novel genomic species. Therefore, a novel species, Mesorhizobium robiniae sp. nov., is proposed, with type strain CCNWYC 115T (=ACCC 14543T =HAMBI 3082T). Strain CCNWYC 115T can form effective nodules only on its original host.


2007 ◽  
Vol 57 (6) ◽  
pp. 1217-1221 ◽  
Author(s):  
Jung-Hoon Yoon ◽  
So-Jung Kang ◽  
Sooyeon Park ◽  
Tae-Kwang Oh

Two Gram-negative, non-spore-forming, motile and helical-shaped bacterial strains, K92T and K93, were isolated from sludge from a dye works in Korea, and their taxonomic positions were investigated by means of a polyphasic approach. Strains K92T and K93 grew optimally at 37 °C and pH 7.0–8.0 in the presence of 0.5 % (w/v) NaCl. They contained Q-10 as the predominant ubiquinone and C18 : 1 ω7c as the major fatty acid. The major polar lipids were phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and two unidentified amino-group-containing lipids that were ninhydrin-positive. Their DNA G+C contents were 70.0 mol%. The 16S rRNA gene sequences of K92T and K93 showed no differences, and the two strains had a mean DNA–DNA relatedness of 93 %. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains K92T and K93 formed a distinct evolutionary lineage within the Alphaproteobacteria. The 16S rRNA gene sequences of strains K92T and K93 exhibited similarity values of less than 91.5 % with respect to the 16S rRNA gene sequences of other members of the Alphaproteobacteria. The two strains were distinguishable from phylogenetically related genera through differences in several phenotypic properties. On the basis of the phenotypic, phylogenetic and genetic data, strains K92T and K93 represent a novel genus and species, for which the name Caenispirillum bisanense gen. nov., sp. nov. is proposed. The type strain of Caenispirillum bisanense is K92T (=KCTC 12839T=JCM 14346T).


2007 ◽  
Vol 57 (9) ◽  
pp. 2037-2051 ◽  
Author(s):  
M. Martini ◽  
I.-M. Lee ◽  
K. D. Bottner ◽  
Y. Zhao ◽  
S. Botti ◽  
...  

Extensive phylogenetic analyses were performed based on sequences of the 16S rRNA gene and two ribosomal protein (rp) genes, rplV (rpl22) and rpsC (rps3), from 46 phytoplasma strains representing 12 phytoplasma 16Sr groups, 16 other mollicutes and 28 Gram-positive walled bacteria. The phylogenetic tree inferred from rp genes had a similar overall topology to that inferred from the 16S rRNA gene. However, the rp gene-based tree gave a more defined phylogenetic interrelationship among mollicutes and Gram-positive walled bacteria. Both phylogenies indicated that mollicutes formed a monophyletic group. Phytoplasmas clustered with Acholeplasma species and formed one clade paraphyletic with a clade consisting of the remaining mollicutes. The closest relatives of mollicutes were low-G+C-content Gram-positive bacteria. Comparative phylogenetic analyses using the 16S rRNA gene and rp genes were performed to evaluate their efficacy in resolving distinct phytoplasma strains. A phylogenetic tree was constructed based on analysis of rp gene sequences from 87 phytoplasma strains belonging to 12 16Sr phytoplasma groups. The phylogenetic relationships among phytoplasmas were generally in agreement with those obtained on the basis of the 16S rRNA gene in the present and previous works. However, the rp gene-based phylogeny allowed for finer resolution of distinct lineages within the phytoplasma 16Sr groups. RFLP analysis of rp gene sequences permitted finer differentiation of phytoplasma strains in a given 16Sr group. In this study, we also designed several semi-universal and 16Sr group-specific rp gene-based primers that allow for the amplification of 11 16Sr group phytoplasmas.


2006 ◽  
Vol 56 (6) ◽  
pp. 1251-1255 ◽  
Author(s):  
Jung-Hoon Yoon ◽  
So-Jung Kang ◽  
Tae-Kwang Oh

A Gram-negative, non-motile, non-spore-forming, slightly halophilic bacterial strain, DSW-5T, was isolated from seawater off Dokdo, Korea, and subjected to a polyphasic taxonomic study. It grew optimally at 25–28 °C and in the presence of 2 % (w/v) NaCl. Strain DSW-5T contained MK-6 as the predominant menaquinone and iso-C15 : 0, iso-C15 : 1 and iso-C15 : 0 3-OH as the major fatty acids. The major polar lipids detected were phosphatidylethanolamine, three unidentified phospholipids and an amino-group-containing lipid. The DNA G+C content was 30.0 mol%. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain DSW-5T was most closely related to the genus Polaribacter. Similarity values between the 16S rRNA gene sequences of strain DSW-5T and the type strains of recognized Polaribacter species were in the range 96.2–96.8 %. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain DSW-5T (=KCTC 12392T=DSM 17204T) was classified in the genus Polaribacter as the type strain of a novel species, for which the name Polaribacter dokdonensis sp. nov. is proposed.


2006 ◽  
Vol 56 (4) ◽  
pp. 777-780 ◽  
Author(s):  
Jung-Hoon Yoon ◽  
Mi-Hwa Lee ◽  
So-Jung Kang ◽  
Tae-Kwang Oh

A Gram-negative, non-motile, non-spore-forming bacterial strain, DS-44T, was isolated from soil from Dokdo in Korea, and its taxonomic position was investigated by using a polyphasic approach. It grew optimally at 25 °C and in the presence of 2 % (w/v) NaCl. Strain DS-44T contained MK-7 as the predominant menaquinone and iso-C15 : 0 and C16 : 1 ω7c and/or iso-C15 : 0 2-OH as the major fatty acids. The DNA G+C content was 49·0 mol%. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain DS-44T belongs to the genus Algoriphagus of the phylum Bacteroidetes. Similarity values between the 16S rRNA gene sequences of strain DS-44T and those of the type strains of recognized Algoriphagus species were in the range 93·8–95·7 %, making it possible to categorize strain DS-44T as a species that is separate from previously described Algoriphagus species. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain DS-44T (=KCTC 12545T=CIP 108837T) was classified in the genus Algoriphagus as the type strain of a novel species, for which the name Algoriphagus terrigena sp. nov. is proposed.


2006 ◽  
Vol 56 (6) ◽  
pp. 1273-1277 ◽  
Author(s):  
Jung-Hoon Yoon ◽  
Mi-Hwa Lee ◽  
So-Jung Kang ◽  
Soo-Yeon Park ◽  
Tae-Kwang Oh

A Gram-negative, non-motile, rod-shaped bacterial strain, designated DS-27T, was isolated from a soil sample, and its taxonomic position was investigated by using a polyphasic approach. The organism grew optimally at 30 °C and in the presence of 0–0.5 % (w/v) NaCl. Strain DS-27T contained MK-7 as the predominant menaquinone and iso-C15 : 0, C16 : 1 ω7c and/or iso-C15 : 0 2-OH and iso-C17 : 0 3-OH as the major fatty acids. The DNA G+C content was 39.7 mol%. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain DS-27T is most closely related to the genus Pedobacter of the family Sphingobacteriaceae. Similarity values between the 16S rRNA gene sequences of strain DS-27T and the type strains of recognized Pedobacter species ranged from 90.6 to 95.5 %. Differential phenotypic properties, together with the phylogenetic distinctiveness, were sufficient to categorize strain DS-27T as representing a species that is separate from recognized Pedobacter species. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain DS-27T (=KCTC 12559T=CIP 108922T) was classified in the genus Pedobacter as a member of a novel species, for which the name Pedobacter sandarakinus sp. nov. is proposed.


2011 ◽  
Vol 61 (11) ◽  
pp. 2676-2681 ◽  
Author(s):  
Gwang Il Jang ◽  
Chung Yeon Hwang ◽  
Byung Cheol Cho

Two Gram-negative-staining, aerobic bacterial strains, designated CL-SC21T and CL-SC22, were isolated from a culture of the diatom Skeletonema costatum (Korean Marine Microalgae Culture Center, KMMCC strain B-396) established from the East Sea, Korea. The two novel strains shared 99.9 % 16S rRNA gene sequence similarity. Analysis of the 16S rRNA gene sequences showed an affiliation with the genus Nitratireductor, with the strains sharing 96.5–97.5 % similarity with the type strains of recognized species of the genus Nitratireductor and being most closely related to Nitratireductor aquibiodomus NL21T. Phylogenetic analyses of the 16S rRNA gene sequences showed that strain CL-SC21T together with strain CL-SC22 belonged to the genus Nitratireductor and formed a robust clade among closely related Nitratireductor species. The polar lipids comprised phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, two unidentified aminophospholipids, an unidentified aminolipid, an unidentified phospholipid and five unidentified lipids. Ubiquinone 10 was the major quinone. The major cellular fatty acids of strains CL-SC21T and CL-SC22 were C18 : 1ω7c (70.6–72.3 %) and C19 : 0ω8c cyclo (10.9–11.8 %). The genomic DNA G+C contents of strains CL-SC21T and CL-SC22 were 56.7 and 57.1 mol%, respectively. The level of DNA–DNA relatedness between strains CL-SC21T and CL-SC22 was 86 % (reciprocal 91 %), indicating that the two isolates represented a single species. However, levels of DNA–DNA relatedness between N. aquibiodomus NL21T and strains CL-SC21T and CL-SC22 were 28 % (reciprocal 45 %) and 25 % (reciprocal 50 %), respectively. Phylogenetic analysis and the results of biochemical tests showed that strains CL-SC21T and CL-SC22 were different from all recognized species of the genus Nitratireductor. Thus, strains CL-SC21T and CL-SC22 represent a novel species of the genus Nitratireductor, for which the name Nitratireductor aquimarinus sp. nov. is proposed. The type strain is CL-SC21T ( = KCCM 90090T = JCM 17288T).


2007 ◽  
Vol 57 (3) ◽  
pp. 444-449 ◽  
Author(s):  
Minna Hannula ◽  
Marja-Liisa Hänninen

Analysis of 16S rRNA gene sequences is one of the most common methods for investigating the phylogeny and taxonomy of bacteria. However, several studies have indicated that the 16S rRNA gene does not distinguish between certain Helicobacter species. We therefore selected for phylogenetic analysis an alternative marker, gyrB, encoding gyrase subunit B. The aim of this investigation was to examine the applicability of gyrB gene fragments (~1100 bp) for the phylogenetic study of 16 Helicobacter species and a total of 33 Helicobacter strains included in this study. Based on the sequenced fragments, a phylogenetic tree was obtained that contained two distinct clusters, with gastric species forming one cluster and enterohepatic species the other. The only exception was the gastric species Helicobacter mustelae, which clustered with the enterohepatic species. The calculated similarity matrix revealed the highest interspecies similarity between Helicobacter salomonis and Helicobacter felis (89 %) and the lowest similarity between Helicobacter pullorum and H. felis (60 %). The DNA G+C content of the sequenced fragments was ⩽40 mol% in enterohepatic species and >46 mol% in gastric species, excluding Helicobacter pylori and H. mustelae, with G+C contents of 34 and 42 mol%, respectively. In summary, the gyrB gene fragments provided superior resolution and reliability to the 16S rRNA gene for differentiating between closely related Helicobacter species. A further outcome of this study was achieved by designing gyrB gene-based species-specific PCR primers for the identification of Helicobacter bizzozeronii.


2007 ◽  
Vol 73 (20) ◽  
pp. 6682-6685 ◽  
Author(s):  
Daniel P. R. Herlemann ◽  
Oliver Geissinger ◽  
Andreas Brune

ABSTRACT The bacterial candidate phylum Termite Group I (TG-1) presently consists mostly of “Endomicrobia,” which are endosymbionts of flagellate protists occurring exclusively in the hindguts of termites and wood-feeding cockroaches. Here, we show that public databases contain many, mostly undocumented 16S rRNA gene sequences from other habitats that are affiliated with the TG-1 phylum but are only distantly related to “Endomicrobia.” Phylogenetic analysis of the expanded data set revealed several diverse and deeply branching lineages comprising clones from many different habitats. In addition, we designed specific primers to explore the diversity and environmental distribution of bacteria in the TG-1 phylum.


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