scholarly journals Oidium neolycopersici: Intraspecific Variability Inferred from Amplified Fragment Length Polymorphism Analysis and Relationship with Closely Related Powdery Mildew Fungi Infecting Various Plant Species

2008 ◽  
Vol 98 (5) ◽  
pp. 529-540 ◽  
Author(s):  
T. Jankovics ◽  
Y. Bai ◽  
G. M. Kovács ◽  
M. Bardin ◽  
P. C. Nicot ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Plant Species ◽  
Length Polymorphism ◽  
Fragment Length ◽  
Fragment Length Polymorphism ◽  
Amplified Fragment Length Polymorphism ◽  
Its Sequences ◽  
Polymorphism Analysis ◽  
Oidium Neolycopersici ◽  
Powdery Mildews

Previous works indicated a considerable variation in the pathogenicity, virulence, and host range of Oidium neolycopersici isolates causing tomato powdery mildew epidemics in many parts of the world. In this study, rDNA internal transcribed spacer (ITS) sequences, and amplified fragment length polymorphism (AFLP) patterns were analyzed in 17 O. neolycopersici samples collected in Europe, North America, and Japan, including those which overcame some of the tomato major resistance genes. The ITS sequences were identical in all 10 samples tested and were also identical to ITS sequences of eight previously studied O. neolycopersici specimens. The AFLP analysis revealed a high genetic diversity in O. neolycopersici and indicated that all 17 samples represented different genotypes. This might suggest the existence of either a yet unrevealed sexual reproduction or other genetic mechanisms that maintain a high genetic variability in O. neolycopersici. No clear correlation was found between the virulence and the AFLP patterns of the O. neolycopersici isolates studied. The relationship between O. neolycopersici and powdery mildew anamorphs infecting Aquilegia vulgaris, Chelidonium majus, Passiflora caerulea, and Sedum alboroseum was also investigated. These anamorphs are morphologically indistinguishable from and phylogenetically closely related to O. neolycopersici. The cross-inoculation tests and the analyses of ITS sequences and AFLP patterns jointly indicated that the powdery mildew anamorphs collected from the above mentioned plant species all represent distinct, but closely related species according to the phylogenetic species recognition. All these species were pathogenic only to their original host plant species, except O. neolycopersici which infected S. alboroseum, tobacco, petunia, and Arabidopsis thaliana, in addition to tomato, in cross-inoculation tests. This is the first genome-wide study that investigates the relationships among powdery mildews that are closely related based on ITS sequences and morphology. The results indicate that morphologically indistinguishable powdery mildews that differed in only one to five single nucleotide positions in their ITS region are to be considered as different taxa with distinct host ranges.

scholarly journals High-Resolution Genotyping of Streptococcus pyogenesSerotype M1 Isolates by Fluorescent Amplified-Fragment Length Polymorphism Analysis

1999 ◽  
Vol 37 (6) ◽  
pp. 1948-1952 ◽  
Author(s):  
Meeta Desai ◽  
Androulla Efstratiou ◽  
Robert George ◽  
John Stanley
Keyword(s):  
Length Polymorphism ◽  
Fragment Length ◽  
Fragment Length Polymorphism ◽  
Geographic Origin ◽  
Amplified Fragment Length Polymorphism ◽  
Discriminatory Power ◽  
Polymorphism Analysis ◽  
Worldwide Distribution ◽  
High Discriminatory Power ◽  
Typing Methods

We have used fluorescent amplified-fragment length polymorphism (FAFLP) analysis to subtype clinical isolates of Streptococcus pyogenes serotype M1. Established typing methods define most M1 isolates as members of a clone that has a worldwide distribution and that is strongly associated with invasive diseases. FAFLP analysis simultaneously sampled 90 to 120 loci throughout the M1 genome. Its discriminatory power, precision, and reproducibility were compared with those of other molecular typing methods. Irrespective of disease symptomatology or geographic origin, the majority of the clinical M1 isolates shared a single ribotype, pulsed-field gel electrophoresis macrorestriction profile, and emm1 gene sequence. Nonetheless, among these isolates, FAFLP analysis could differentiate 17 distinct profiles, including seven multi-isolate groups. The FAFLP profiles of M1 isolates reproducibly exhibited between 1 and more than 20 amplified fragment differences. The high discriminatory power of genotyping by FAFLP analysis revealed genetic microheterogeneity and differentiated otherwise “identical” M1 isolates as members of a clone complex.

scholarly journals Genomic Relatedness of ChlamydiaIsolates Determined by Amplified Fragment Length Polymorphism Analysis

1999 ◽  
Vol 181 (15) ◽  
pp. 4469-4475 ◽  
Author(s):  
Adam Meijer ◽  
Servaas A. Morré ◽  
Adriaan J. C. Van Den Brule ◽  
Paul H. M. Savelkoul ◽  
Jacobus M. Ossewaarde
Keyword(s):  
Cluster Analysis ◽  
Length Polymorphism ◽  
Fragment Length ◽  
Fragment Length Polymorphism ◽  
Amplified Fragment Length Polymorphism ◽  
Chlamydia Psittaci ◽  
Rrna Genes ◽  
Aflp Analysis ◽  
Polymorphism Analysis ◽  
Genomic Relatedness

ABSTRACT The genomic relatedness of 19 Chlamydia pneumoniaeisolates (17 from respiratory origin and 2 from atherosclerotic origin), 21 Chlamydia trachomatis isolates (all serovars from the human biovar, an isolate from the mouse biovar, and a porcine isolate), 6 Chlamydia psittaci isolates (5 avian isolates and 1 feline isolate), and 1 Chlamydia pecorum isolate was studied by analyzing genomic amplified fragment length polymorphism (AFLP) fingerprints. The AFLP procedure was adapted from a previously developed method for characterization of clinical C. trachomatis isolates. The fingerprints of all C. pneumoniae isolates were nearly identical, clustering together at a Dice similarity of 92.6% (± 1.6% standard deviation). The fingerprints of the C. trachomatis isolates of human, mouse, and swine origin were clearly distinct from each other. The fingerprints of the isolates from the human biovar could be divided into at least 12 different types when the presence or absence of specific bands was taken into account. The C. psittacifingerprints could be divided into a parakeet, a pigeon, and a feline type. The fingerprint of C. pecorum was clearly distinct from all others. Cluster analysis of selected isolates from all species revealed groups other than those based on sequence data from single genes (in particular, omp1 and rRNA genes) but was in agreement with available DNA-DNA hybridization data. In conclusion, cluster analysis of AFLP fingerprints of representatives of all species provided suggestions for a grouping of chlamydiae based on the analysis of the whole genome. Furthermore, genomic AFLP analysis showed that the genome of C. pneumoniae is highly conserved and that no differences exist between isolates of respiratory and atherosclerotic origins.

Predictive Fluorescent Amplified-Fragment Length Polymorphism Analysis of Escherichia coli: High-Resolution Typing Method with Phylogenetic Significance

1999 ◽  
Vol 37 (5) ◽  
pp. 1274-1279 ◽  
Author(s):  
Catherine Arnold ◽  
Lou Metherell ◽  
Geraldine Willshaw ◽  
Anthony Maggs ◽  
John Stanley
Keyword(s):  
Escherichia Coli ◽  
High Resolution ◽  
Length Polymorphism ◽  
Fragment Length ◽  
Fragment Length Polymorphism ◽  
Amplified Fragment Length Polymorphism ◽  
Polymorphism Analysis ◽  
Enzyme Electrophoresis ◽  
Typing Method ◽  
E Coli

The fluorescent amplified-fragment length polymorphism (FAFLP) assay potentially amplifies a unique set of genome fragments from each bacterial clone. It uses stringently hybridizing primers which carry a fluorescent label. Precise fragment sizing is achieved by the inclusion of an internal size standard in every lane. Therefore, a unique genotype identifier(s) can be found in the form of fragments of precise size or sizes, and these can be generated reproducibly. In order to evaluate the potential of FAFLP as an epidemiological typing method with a valid phylogenetic basis, we applied it to 87 strains ofEscherichia coli. These comprised the EcoR collection, which has previously been classified by multilocus enzyme electrophoresis (MLEE) and which represents the genetic diversity of the species E. coli, plus 15 strains of the clinically important serogroup O157. FAFLP with an unlabelled nonselectiveEcoRI primer (Eco+0) and a labelled selectiveMseI primer (Mse+TA) gave strain-specific profiles. Fragments of identical sizes (in base pairs) were assumed to be identical, and the genetic distances between the strains were calculated. A phylogenetic tree derived from measure of distance correlated closely with the MLEE groupings of the EcoR collection and placed the verocytotoxin-producing O157 strains on an outlier branch. Our data indicate that FAFLP is suitable for epidemiological investigation of E. coli infection, providing well-defined and reproducible identifiers of genotype for each strain. Since FAFLP objectively samples the whole genome, each strain or isolate can be assigned a place within the broad context of the whole species and can also be subjected to a high-resolution comparison with closely related strains to investigate epidemiological clonality.

Comparative Fingerprinting Analysis ofCampylobacter jejuni subsp. jejuni Strains by Amplified-Fragment Length Polymorphism Genotyping

2000 ◽  
Vol 38 (9) ◽  
pp. 3379-3387 ◽  
Author(s):  
Bjørn-Arne Lindstedt ◽  
Even Heir ◽  
Traute Vardund ◽  
Kjetil K. Melby ◽  
Georg Kapperud
Keyword(s):  
Length Polymorphism ◽  
Fragment Length ◽  
Fragment Length Polymorphism ◽  
Amplified Fragment Length Polymorphism ◽  
Epidemiological Surveillance ◽  
Aflp Analysis ◽  
Polymorphism Analysis ◽  
Pcr Rflp ◽  
Pcr Products ◽  
Ofcampylobacter Jejuni

Amplified-fragment length polymorphism (AFLP) analysis with the endonucleases BglII and MfeI was used to genotype 91 Campylobacter jejuni subsp. jejunistrains from outbreaks and sporadic cases. AFLP-generated fragments were labeled with fluorescent dye and separated by capillary electrophoresis. The software packages GeneScan and GelCompar II were used to calculate AFLP pattern similarities and to investigate phylogenetic relationships among the genotyped strains. The AFLP method was compared with two additional DNA-based typing methods, pulsed-field gel electrophoresis (PFGE) using SmaI and restriction fragment length polymorphism analysis on PCR products (PCR-RFLP) of theflaA and flaB genes. We found that AFLP analysis of C. jejuni strains is a rapid method that offers better discriminatory power than do both PFGE and PCR-RFLP. AFLP and, to a lesser extent, PCR-RFLP could differentiate strains within the same PFGE profiles, which also makes PCR-RFLP an alternative to PFGE. We were able to clearly distinguish 9 of 10 recognized outbreaks by AFLP and to identify similarities among outbreak and sporadic strains. Therefore, AFLP is suitable for epidemiological surveillance ofC. jejuni and will be an excellent tool for source identification in outbreak situations.

scholarly journals Amplified-Fragment Length Polymorphism Analysis: the State of an Art

1999 ◽  
Vol 37 (10) ◽  
pp. 3083-3091 ◽  
Author(s):  
P. H. M. Savelkoul ◽  
H. J. M. Aarts ◽  
J. de Haas ◽  
L. Dijkshoorn ◽  
B. Duim ◽  
...  
Keyword(s):  
Length Polymorphism ◽  
Fragment Length ◽  
Fragment Length Polymorphism ◽  
Amplified Fragment Length Polymorphism ◽  
The State ◽  
Polymorphism Analysis
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