scholarly journals Cryptic haplotypes of "Candidatus Liberibacter africanus"

2015 ◽  
Author(s):  
Warrick Nelson ◽  
Sandrine Eveillard ◽  
Marie-Pierre Dubrana ◽  
Joseph Bové
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
16S Rdna ◽  
Rrna Gene ◽  
Gene Sequences ◽  
16S Rrna Gene Sequences ◽  
Rdna Sequences ◽  
New Information ◽  
Candidatus Liberibacter ◽  
Citrus Leaves

“Candidatus Liberibacter africanus” (Laf) has long been recognised as a causal agent of the devastating citrus disease huanglongbing (HLB) or citrus greening. This species is currently restricted to Africa, the Arabian Peninsula and some Indian Ocean islands and vectored by the African citrus psyllid, Trioza erytreae. Blotchy mottle on citrus leaves is characteristic of the disease. Somewhat similar symptoms in the Rutaceous tree Calodendrum capensis (Cape Chestnut) resulted in the discovery of Laf outside commercial citrus crops in South Africa. This was classed as a subspecies of Laf (capensis, hence LafC). In subsequent surveys of both commercial citrus crops and Calodendrum, both natural and ornamental specimens, LafC was not found in the citrus crop, nor has Laf been found in C. capensis. HLB was reported from Madagascar in 1968 but no sequences from this source have so far been published. Until fairly recently, only the reference 16S rRNA gene sequences of Laf (L22533) and LafC (AF137368) had been deposited in GenBank. Both of these reference sequences contain a number of unresolved nucleotides. Resolving these nucleotide positions by aligning against more recently available sequences, it becomes evident that these unresolved positions represent one percentage point difference in similarity between Laf and LafC. The originally reported 97.4% similarity is therefore incorrect based on this new information. Recalculating the similarity on the full length 16S rDNA sequence results in 99.54% similarity, a value too high to justify a subspecies status. LafC should therefore be reduced to that of a haplotype of Laf. Further, the six 16S rRNA gene sequences currently available in GenBank identified as the species Laf separate into 2 haplotype groups. The 3 haplotypes of Laf are therefore LafA designated as the first accession sequenced (L22533), LafC for the former capensis subspecies and to recognise the prior use of this term, and LafB for the third haplotype not previously recognised. Thus the cryptic presence of 3 haplotypes is revealed by this review of the Laf 16S rDNA sequences.

scholarly journals Estimation of the Relative Abundance of DifferentBacteroides and Prevotella Ribotypes in Gut Samples by Restriction Enzyme Profiling of PCR-Amplified 16S rRNA Gene Sequences

1998 ◽  
Vol 64 (10) ◽  
pp. 3683-3689 ◽  
Author(s):  
Jacqueline Wood ◽  
Karen P. Scott ◽  
Gorazd Avguštin ◽  
C. James Newbold ◽  
Harry J. Flint
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
16S Rdna ◽  
Restriction Enzymes ◽  
Pcr Primers ◽  
Gut Contents ◽  
Rrna Gene ◽  
Gene Sequences ◽  
16S Rrna Gene Sequences ◽  
Bacterial Populations

ABSTRACT We describe an approach for determining the genetic composition ofBacteroides and Prevotellapopulations in gut contents based on selective amplification of 16S rRNA gene sequences (rDNA) followed by cleavage of the amplified material with restriction enzymes. The relative contributions of different ribotypes to total Bacteroides andPrevotella 16S rDNA are estimated after end labelling of one of the PCR primers, and the contribution ofBacteroides and Prevotellasequences to total eubacterial 16S rDNA is estimated by measuring the binding of oligonucleotide probes to amplified DNA.Bacteroides and Prevotella 16S rDNA accounted for between 12 and 62% of total eubacterial 16S rDNA in samples of ruminal contents from six sheep and a cow. Ribotypes 4, 5, 6, and 7, which include most cultivated rumen Prevotellastrains, together accounted for between 20 and 86% of the total amplified Bacteroides andPrevotella rDNA in these samples. The most abundantBacteroides or Prevotella ribotype in four animals, however, was ribotype 8, for which there is only one known cultured isolate, while ribotypes 1 and 2, which include many colonic Bacteroides spp., were the most abundant in two animals. This indicates that some abundantBacteroides and Prevotella groups in the rumen are underrepresented among cultured rumenPrevotella isolates. The approach described here provides a rapid, convenient, and widely applicable method for comparing the genotypic composition of bacterial populations in gut samples.

scholarly journals Comparison of two approaches for the classification of 16S rRNA gene sequences

2014 ◽  
Vol 63 (10) ◽  
pp. 1311-1315 ◽  
Author(s):  
Sonia Chatellier ◽  
Nathalie Mugnier ◽  
Françoise Allard ◽  
Bertrand Bonnaud ◽  
Valérie Collin ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
16S Rdna ◽  
Rrna Gene ◽  
Research Database ◽  
16S Rdna Sequencing ◽  
Gene Sequences ◽  
16S Rrna Gene Sequences ◽  
Rdna Sequencing ◽  
Lowest Common Ancestor

The use of 16S rRNA gene sequences for microbial identification in clinical microbiology is accepted widely, and requires databases and algorithms. We compared a new research database containing curated 16S rRNA gene sequences in combination with the lca (lowest common ancestor) algorithm (RDB-LCA) to a commercially available 16S rDNA Centroid approach. We used 1025 bacterial isolates characterized by biochemistry, matrix-assisted laser desorption/ionization time-of-flight MS and 16S rDNA sequencing. Nearly 80 % of isolates were identified unambiguously at the species level by both classification platforms used. The remaining isolates were mostly identified correctly at the genus level due to the limited resolution of 16S rDNA sequencing. Discrepancies between both 16S rDNA platforms were due to differences in database content and the algorithm used, and could amount to up to 10.5 %. Up to 1.4 % of the analyses were found to be inconclusive. It is important to realize that despite the overall good performance of the pipelines for analysis, some inconclusive results remain that require additional in-depth analysis performed using supplementary methods.

scholarly journals Clover Proliferation Group (16SrVI) Subgroup A (16SrVI-A) Phytoplasma is a Probable Causal Agent of Dry Bean Phyllody Disease in Washington

Plant Disease ◽  
2004 ◽  
Vol 88 (4) ◽  
pp. 429-429
Author(s):  
I.-M. Lee ◽  
K. D. Bottner ◽  
P. N. Miklas ◽  
M. A. Pastor-Corrales
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
16S Rdna ◽  
Sequence Homology ◽  
Rrna Gene ◽  
16S Rrna Gene Sequences ◽  
Dry Bean ◽  
Rdna Sequences ◽  
Bean Plants ◽  
16S Rdna Sequences

During 2003, a new disease, dry bean phyllody (DBPh), was observed in the Columbia Basin of Washington in dry bean (Phaseolus vulgaris L.) cultivars of Andean origin grown in Mattawa and Paterson, WA that caused great reduction in dry bean production. Symptoms of DBPh became apparent during mid-to-late pod development and were characterized by leafy petals (phyllody) and aborted seed pods resembling thin, twisted, and corrugated leaf-like structures. Deformed sterile pods that were small, sickle-shaped, upright, and leathery were also observed. The infected plants generally exhibited chlorosis, stunting, or bud proliferation from leaf axils. Symptoms of DBPh were indicative of possible infection by phytoplasmas. Restriction fragment length polymorphism (RFLP) and phylogenetic analyses of amplified 16S rDNA sequences were used for phytoplasma identification. Four symptomatic bean plants were analyzed and tested positive for phytoplasma infection on the basis of results of initial polymerase chain reaction (PCR) and subsequent nested-PCR amplifications (2). RFLP analyses of 16S rDNA sequences with restriction enzymes, MseI, AluI, HhaI, RsaI, and HpaII indicated that the phytoplasma strains associated with DBPh belonged to the clover proliferation group (16SrVI) subgroup A (16SrVI-A) (2). This subgroup currently consists of three members, clover proliferation (CP; GenBank Accession No. AY500130), potato witches'-broom (PWB; GenBank Accession No. AY500818), and vinca virescence (VR; GenBank Accession No. AY500817), a strain of beet leafhopper-transmitted virescence agent (BLTVA) phytoplasmas (1,2). The taxonomic affiliations of the DBPh phytoplasma strains were confirmed by phylogenetic analysis of cloned 16S rRNA gene sequences (GenBank Accession Nos. DBPh2, AY496002; DBPh3, AY496003). Among the existing members of subgroup 16SrVI-A, the four DBPh strains were closely related to the VR strain with 99.7% 16S rDNA sequence homology and to the CP strain with 99.2% sequence homology. To gain further evidence on the role of 16SrVI-A phytoplasma strains in DBPh disease, a modified test of Koch's postulates was conducted. Infected tissue from one phytoplasma-positive dry bean sample was grafted onto three Pinto UI-114 bean seedlings in the greenhouse. Within 60 days, the bean seedlings exhibited corrugated leaf-like structures from aborted seedpods, a lack of flower formation, general chlorosis, and stunting similar to the original diseased plants. The lower leaves of the inoculated bean plants became epinastic and leathery. The transmitted phytoplasma was detected in each of the grafted symptomatic seedlings, and the RFLP patterns of its 16S rRNA gene sequences were identical to those of the phytoplasmas in the scions. A high correlation between the presence of disease symptoms and the presence of subgroup 16SrVI-A phytoplasmas in the bean plants suggests that these phytoplasmas play an etiological role in DBPh disease. To our knowledge, these findings provide the first confirmed case of phytoplasma-associated DBPh in the United States. References: (1) D. A. Golino et al. Plant Dis. 73:850, 1989. (2) I.-M. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1998.

scholarly journals Molecular Characterization and Detection of 16SrIII Group Phytoplasma Associated with Huanglongbing Symptoms

2019 ◽  
Vol 109 (3) ◽  
pp. 366-374 ◽  
Author(s):  
Nelson Arno Wulff ◽  
Camila Giacomo Fassini ◽  
Viviani Vieira Marques ◽  
Elaine Cristina Martins ◽  
Daniela Aparecida Bononi Coletti ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Diagnostic Tools ◽  
Melia Azedarach ◽  
Rrna Gene ◽  
Nucleotide Polymorphisms ◽  
Gene Sequences ◽  
16S Rrna Gene Sequences ◽  
Candidatus Liberibacter ◽  
A Minor

When huanglongbing (HLB) was found in Brazil in 2004, ‘Candidatus Liberibacter americanus’ was infecting most of the trees while ‘Ca. L. asiaticus’ was present in a minor proportion. Currently, ‘Ca. L. asiaticus’ is the predominant bacterium associated with HLB in citrus trees in São Paulo (SP) and Minas Gerais (MG) States, the major citrus-growing regions in Brazil. A phytoplasma from the 16SrIX group was associated with HLB symptoms in Brazil in 2007, in plants free of Liberibacter spp. In this report, HLB samples testing negative for ‘Ca. L. asiaticus’, ‘Ca. L. americanus’, and 16SrIX phytoplasma were infected with 16SrIII phytoplasmas. Coinfection with ‘Ca. L. asiaticus’ and 16SrIII was also found. The 16S ribosomal RNA (rRNA) gene sequences from 22 samples were obtained and sequenced, confirming that the 16SrIII group phytoplasma is associated with HLB symptoms in SP and MG States. Ten single-nucleotide polymorphisms (SNPs) were found in the 1,427-bp 16S rRNA gene sequences from 16SrIII phytoplasmas from citrus, whereas none was detected in 16S rRNA gene sequences among 16SrIX phytoplasma from citrus. Ribosomal protein (rp) rpsSrplVrpsC gene sequences were amplified with 16SrIII group-specific primers, sequenced from a subset of nine samples, and assembled into three groups based on eight SNPs. SNPs in 16S rRNA gene and rp gene sequences are common in 16SrIII phytoplasmas from other hosts and this phytoplasma group is widespread in South America. 16SrIII phytoplasmas highly related are commonly found in Melia azedarach, a widespread tree in Brazil and Argentina. The finding of a new phytoplasma associated with HLB symptoms belonging to the 16SrIII group reinforces the need to develop diagnostic tools to assess HLB-associated microbiomes.

Monoglobus pectinilyticus gen. nov., sp. nov., a pectinolytic bacterium isolated from human faeces.

2020 ◽  
Author(s):  
CC Kim ◽  
WJ Kelly ◽  
ML Patchett ◽  
GW Tannock ◽  
Z Jordens ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Sequence Similarity ◽  
Middle Lamella ◽  
Rrna Gene ◽  
Gene Sequences ◽  
16S Rrna Gene Sequences ◽  
Citrus Peel ◽  
Human Faeces ◽  
The Family

© 2017 IUMS. A novel anaerobic pectinolytic bacterium (strain 14T) was isolated from human faeces. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain 14T belonged to the family Ruminococcaceae, but was located separately from known clostridial clusters within the taxon. The closest cultured relative of strain 14T was Acetivibrio cellulolyticus (89.7% sequence similarity). Strain 14T shared ~99% sequence similarity with cloned 16S rRNA gene sequences from uncultured bacteria derived from the human gut. Cells were Gram-stain-positive, non-motile cocci approximately 0.6μm in diameter. Strain 14T fermented pectins from citrus peel, apple, and kiwifruit as well as carbohydrates that are constituents of pectins and hemicellulose, such as galacturonic acid, xylose, and arabinose. TEM images of strain 14T, cultured in association with plant tissues, suggested extracellular fibrolytic activity associated with the bacterial cells, forming zones of degradation in the pectin-rich regions of middle lamella. Phylogenetic and phenotypic analysis supported the differentiation of strain 14T as a novel genus in the family Ruminococcaceae. The name Monoglobus pectinilyticus gen. nov., sp. nov. is proposed; the type strain is 14T (JCM 31914T=DSM 104782T).

scholarly journals The Termite Group I Phylum Is Highly Diverse and Widespread in the Environment

2007 ◽  
Vol 73 (20) ◽  
pp. 6682-6685 ◽  
Author(s):  
Daniel P. R. Herlemann ◽  
Oliver Geissinger ◽  
Andreas Brune
Keyword(s):  
Phylogenetic Analysis ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Rrna Gene ◽  
Gene Sequences ◽  
16S Rrna Gene Sequences ◽  
Specific Primers ◽  
Environmental Distribution ◽  
Data Set ◽  
Group I

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.

scholarly journals Microbiological and Geochemical Heterogeneity in an In Situ Uranium Bioremediation Field Site

2005 ◽  
Vol 71 (10) ◽  
pp. 6308-6318 ◽  
Author(s):  
Helen A. Vrionis ◽  
Robert T. Anderson ◽  
Irene Ortiz-Bernad ◽  
Kathleen R. O'Neill ◽  
Charles T. Resch ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Acid Volatile Sulfide ◽  
Rrna Gene ◽  
Gene Sequences ◽  
16S Rrna Gene Sequences ◽  
Geochemical Heterogeneity

ABSTRACT The geochemistry and microbiology of a uranium-contaminated subsurface environment that had undergone two seasons of acetate addition to stimulate microbial U(VI) reduction was examined. There were distinct horizontal and vertical geochemical gradients that could be attributed in large part to the manner in which acetate was distributed in the aquifer, with more reduction of Fe(III) and sulfate occurring at greater depths and closer to the point of acetate injection. Clone libraries of 16S rRNA genes derived from sediments and groundwater indicated an enrichment of sulfate-reducing bacteria in the order Desulfobacterales in sediment and groundwater samples. These samples were collected nearest the injection gallery where microbially reducible Fe(III) oxides were highly depleted, groundwater sulfate concentrations were low, and increases in acid volatile sulfide were observed in the sediment. Further down-gradient, metal-reducing conditions were present as indicated by intermediate Fe(II)/Fe(total) ratios, lower acid volatile sulfide values, and increased abundance of 16S rRNA gene sequences belonging to the dissimilatory Fe(III)- and U(VI)-reducing family Geobacteraceae. Maximal Fe(III) and U(VI) reduction correlated with maximal recovery of Geobacteraceae 16S rRNA gene sequences in both groundwater and sediment; however, the sites at which these maxima occurred were spatially separated within the aquifer. The substantial microbial and geochemical heterogeneity at this site demonstrates that attempts should be made to deliver acetate in a more uniform manner and that closely spaced sampling intervals, horizontally and vertically, in both sediment and groundwater are necessary in order to obtain a more in-depth understanding of microbial processes and the relative contribution of attached and planktonic populations to in situ uranium bioremediation.

scholarly journals Biogeochemistry and Community Composition of Iron- and Sulfur-Precipitating Microbial Mats at the Chefren Mud Volcano (Nile Deep Sea Fan, Eastern Mediterranean)

2008 ◽  
Vol 74 (10) ◽  
pp. 3198-3215 ◽  
Author(s):  
Enoma O. Omoregie ◽  
Vincent Mastalerz ◽  
Gert de Lange ◽  
Kristina L. Straub ◽  
Andreas Kappler ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Microbial Mats ◽  
Eastern Mediterranean ◽  
Sulfide Oxidation ◽  
Mud Volcano ◽  
Rrna Gene ◽  
Anaerobic Oxidation Of Methane ◽  
Gene Sequences ◽  
16S Rrna Gene Sequences

ABSTRACT In this study we determined the composition and biogeochemistry of novel, brightly colored, white and orange microbial mats at the surface of a brine seep at the outer rim of the Chefren mud volcano. These mats were interspersed with one another, but their underlying sediment biogeochemistries differed considerably. Microscopy revealed that the white mats were granules composed of elemental S filaments, similar to those produced by the sulfide-oxidizing epsilonproteobacterium “Candidatus Arcobacter sulfidicus.” Fluorescence in situ hybridization indicated that microorganisms targeted by a “Ca. Arcobacter sulfidicus”-specific oligonucleotide probe constituted up to 24% of the total the cells within these mats. Several 16S rRNA gene sequences from organisms closely related to “Ca. Arcobacter sulfidicus” were identified. In contrast, the orange mat consisted mostly of bright orange flakes composed of empty Fe(III) (hydr)oxide-coated microbial sheaths, similar to those produced by the neutrophilic Fe(II)-oxidizing betaproteobacterium Leptothrix ochracea. None of the 16S rRNA gene sequences obtained from these samples were closely related to sequences of known neutrophilic aerobic Fe(II)-oxidizing bacteria. The sediments below both types of mats showed relatively high sulfate reduction rates (300 nmol·cm−3·day−1) partially fueled by the anaerobic oxidation of methane (10 to 20 nmol·cm−3·day−1). Free sulfide produced below the white mat was depleted by sulfide oxidation within the mat itself. Below the orange mat free Fe(II) reached the surface layer and was depleted in part by microbial Fe(II) oxidation. Both mats and the sediments underneath them hosted very diverse microbial communities and contained mineral precipitates, most likely due to differences in fluid flow patterns.

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