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Open accessJournal ArticleDOI: 10.1073/PNAS.95.5.2044

Multiple evolutionary origins of the fungus causing Panama disease of banana: Concordant evidence from nuclear and mitochondrial gene genealogies

03 Mar 1998-Proceedings of the National Academy of Sciences of the United States of America (National Academy of Sciences)-Vol. 95, Iss: 5, pp 2044-2049
Abstract: Panama disease of banana, caused by the fungus Fusarium oxysporum f. sp. cubense, is a serious constraint both to the commercial production of banana and cultivation for subsistence agriculture. Previous work has indicated that F. oxysporum f. sp. cubense consists of several clonal lineages that may be genetically distant. In this study we tested whether lineages of the Panama disease pathogen have a monophyletic origin by comparing DNA sequences of nuclear and mitochondrial genes. DNA sequences were obtained for translation elongation factor 1α and the mitochondrial small subunit ribosomal RNA genes for F. oxysporum strains from banana, pathogenic strains from other hosts and putatively nonpathogenic isolates of F. oxysporum. Cladograms for the two genes were highly concordant and a partition-homogeneity test indicated the two datasets could be combined. The tree inferred from the combined dataset resolved five lineages corresponding to “F. oxysporum f. sp. cubense” with a large dichotomy between two taxa represented by strains most commonly isolated from bananas with Panama disease. The results also demonstrate that the latter two taxa have significantly different chromosome numbers. F. oxysporum isolates collected as nonpathogenic or pathogenic to other hosts that have very similar or identical elongation factor 1α and mitochondrial small subunit genotypes as banana pathogens were shown to cause little or no disease on banana. Taken together, these results indicate Panama disease of banana is caused by fungi with independent evolutionary origins. more

Topics: Fusarium oxysporum f.sp. cubense (66%), Panama disease (64%), Fusarium oxysporum (61%) more

Open accessJournal ArticleDOI: 10.1111/J.1364-3703.2011.00783.X
Abstract: The aim of this review was to survey all fungal pathologists with an association with the journal Molecular Plant Pathology and ask them to nominate which fungal pathogens they would place in a 'Top 10' based on scientific/economic importance. The survey generated 495 votes from the international community, and resulted in the generation of a Top 10 fungal plant pathogen list for Molecular Plant Pathology. The Top 10 list includes, in rank order, (1) Magnaporthe oryzae; (2) Botrytis cinerea; (3) Puccinia spp.; (4) Fusarium graminearum; (5) Fusarium oxysporum; (6) Blumeria graminis; (7) Mycosphaerella graminicola; (8) Colletotrichum spp.; (9) Ustilago maydis; (10) Melampsora lini, with honourable mentions for fungi just missing out on the Top 10, including Phakopsora pachyrhizi and Rhizoctonia solani. This article presents a short resume of each fungus in the Top 10 list and its importance, with the intent of initiating discussion and debate amongst the plant mycology community, as well as laying down a bench-mark. It will be interesting to see in future years how perceptions change and what fungi will comprise any future Top 10. more

Topics: Plant Mycology (54%), Puccinia (52%), Phakopsora pachyrhizi (50%)

2,078 Citations

Journal ArticleDOI: 10.2307/3761358
Ignazio Carbone1, Linda M. Kohn1Institutions (1)
01 May 1999-Mycologia
Abstract: A simple method is described for designing primer sets that can amplify specific protein-encoding sequences in a wide variety of filamentous ascomycetes. Using this technique, we successfully desig... more

1,779 Citations

Open accessJournal ArticleDOI: 10.1038/NATURE08850
18 Mar 2010-Nature
Abstract: Fusarium species are among the most important phytopathogenic and toxigenic fungi. To understand the molecular underpinnings of pathogenicity in the genus Fusarium, we compared the genomes of three phenotypically diverse species: Fusarium graminearum, Fusarium verticillioides and Fusarium oxysporum f. sp. lycopersici. Our analysis revealed lineage-specific (LS) genomic regions in F. oxysporum that include four entire chromosomes and account for more than one-quarter of the genome. LS regions are rich in transposons and genes with distinct evolutionary profiles but related to pathogenicity, indicative of horizontal acquisition. Experimentally, we demonstrate the transfer of two LS chromosomes between strains of F. oxysporum, converting a non-pathogenic strain into a pathogen. Transfer of LS chromosomes between otherwise genetically isolated strains explains the polyphyletic origin of host specificity and the emergence of new pathogenic lineages in F. oxysporum. These findings put the evolution of fungal pathogenicity into a new perspective. more

Topics: Fusarium oxysporum (61%), Fungal genetics (53%), Fusarium (51%) more

1,205 Citations

Journal ArticleDOI: 10.1023/B:EJPP.0000032386.75915.A0
Abstract: One of the greatest impediments to the study of Fusarium has been the incorrect and confused application of species names to toxigenic and pathogenic isolates, owing in large part to intrinsic limitations of morphological species recognition and its application. To address this problem, we have created FUSARIUM-ID v. 1.0, a publicly available database of partial translation elongation factor 1-alpha (TEF) DNA sequences, presently representing a selected sample of the diversity of the genus diversity, with excellent representation of Type-B trichothecene toxin producers, and the Gibberella fujikuroi, Fusarium oxysporum and F. solani species complexes. Users can generate sequences using primers that are conserved across the genus, and use the sequence as a query to BLAST the database, which can be accessed at, or in a phylogenetic analysis. Correct identification of a known species in these groups often can be performed using this gene region alone. This growing database will contain only vouchered sequences attached to publicly available cultures. In the future, FUSARIUM-ID will be expanded to include additional sequences, including multiple sequences from the same species, sequences from new and revised species, and information from additional genes. more

Topics: Sequence database (62%), Fusarium solani (53%), Fusarium incarnatum (52%)

849 Citations

Open accessJournal ArticleDOI: 10.1073/PNAS.130193297
Abstract: During the past decade, the plant disease called scab or Fusarium head blight of wheat and barley has reached epidemic proportions in North America and elsewhere in the world. Scab is an economically devastating plant disease, not only because it causes significant reduction in seed yields and quality, but also because infested seeds are often contaminated with trichothecene and estrogenic mycotoxins that pose a serious threat to animal health and food safety. To test whether the primary etiological agent of scab, the fungus Fusarium graminearum, is panmictic throughout its range, allelic genealogies were constructed from six single-copy nuclear genes from strains selected to represent the global genetic diversity of this pathogen. Excluding one hybrid strain, all six genealogies recovered the same seven biogeographically structured lineages, suggesting that they represent phylogenetically distinct species among which gene flow has been very limited during their evolutionary history. Parsimony analysis of the combined data set comprising 7,120 aligned nucleotide characters resolved most relationships among the seven lineages of the F. graminearum clade and related fusaria included in the study. Phylogenetic evidence is also presented for introgressive hybridization and intragenic recombination among lineages of the F. graminearum clade in nature. more

Topics: Gibberella zeae (60%), Plant disease (54%)

749 Citations


Journal ArticleDOI: 10.1093/SYSBIO/42.2.182
01 Jun 1993-Systematic Biology
Abstract: Bootstrapping is a common method for assessing confidence in phylogenetic anal? yses. Although bootstrapping was first applied in phylogenetics to assess the repeatability of a given result, bootstrap results are commonly interpreted as a measure of the probability that a phylogenetic estimate represents the true phylogeny. Here we use computer simulations and a laboratory-generated phylogeny to test bootstrapping results of parsimony analyses, both as measures of repeatability (i.e., the probability of repeating a result given a new sample of characters) and accuracy (i.e., the probability that a result represents the true phylogeny). Our results indicate that any given bootstrap proportion provides an unbiased but highly imprecise measure of repeatability, unless the actual probability of replicating the relevant result is nearly one. The imprecision of the estimate is great enough to render the estimate virtually useless as a measure of repeatability. Under conditions thought to be typical of most phylogenetic analyses, however, bootstrap proportions in majority-rule consensus trees provide biased but highly con? servative estimates of the probability of correctly inferring the corresponding clades. Specifically, under conditions of equal rates of change, symmetric phylogenies, and internodal change of 70% usually correspond to a probability of >95% that the corresponding dade is real. However, under conditions of very high rates of internodal change (approaching randomization of the characters among taxa) or highly unequal rates of change among taxa, bootstrap proportions >50% are overestimates of accuracy. (Boot? strapping; accuracy; repeatability; phylogeny; parsimony; precision; statistical analyses; simu? lations.) more

3,847 Citations

Journal ArticleDOI: 10.2307/4109469
01 Jan 1972-Kew Bulletin

2,145 Citations

Journal ArticleDOI: 10.1006/MPEV.1996.0376
Kerry O'Donnell1, Elizabeth Cigelnik1Institutions (1)
Abstract: The evolutionary history of the phytopathogenic Gibberella fujikuroi complex of Fusarium and related species was investigated by cladistic analysis of DNA sequences obtained from multiple unlinked loci. Gene phylogenies inferred from the mitochondrial small subunit (mtSSU) rDNA, nuclear 28S rDNA, and beta-tubulin gene were generally concordant, providing strong support for a fully resolved phylogeny of all biological and most morphological species. Discordance of the nuclear rDNA internal transcribed spacer 2 (ITS2) gene tree is due to paralogous or xenologous ITS2 sequences. PCR and sequence analysis demonstrated that every strain of the ingroup species tested possesses two highly divergent nonorthologous ITS2 types designated type I and type II. Only the major ITS2 type, however, is discernable when PCR products are amplified and sequenced directly with conserved primers. The minor ITS2 type was recovered using ITS2 type-specific PCR primers. Distribution of the major ITS2 type within the species lineages exhibits a homoplastic pattern of evolution, thus obscuring true phylogenetic relationships. The results suggest that the ancestral ITS2 types may have arisen following an ancient interspecific hybridization or gene duplication which occurred prior to the evolutionary radiation of the Gibberella fujikuroi complex and related species of Fusarium. The results also indicate that current morphological-based taxonomic schemes for these fungi are unnatural and a new classification is required. more

Topics: Lineage (evolution) (57%), Phylogenetic tree (55%), Phylogenetics (53%) more

1,461 Citations

Journal ArticleDOI: 10.1146/ANNUREV.ES.22.110191.002521
Abstract: The fungi comprise both members of the kingdom Fungi as we now recognize it (Ascomycota, Basidiomycota, Zygomycota, and Chytridiomycota) and fungal-like protists such as the Oomycota and the cellular and acellular slime molds (Myxomycota and Acrasiomycota). Treating this admittedly polyphyletic assemblage as a group is useful because these organisms often fill rather similar roles within ecosystems, and they have traditionally been studied almost exclusively by mycologists and plant pathologists. Throughout this review, Fungi will refer to the Kingdom, fungi to the organisms studied by mycologists. The fungi, as thus defined, are of great importance for the following reasons: (a) They are the primary decomposers in all terrestrial ecosystems; (b) they are important symbiotic associates of vascular plants both in mutualistic and parasitic relationships; (c) they constitute the overwhelming majority of plant pathogens and as such have a tremendous eco- more

Topics: Chytridiomycota (52%), Slime mold (50%)

902 Citations

Journal ArticleDOI: 10.1016/0169-5347(96)10006-9
Abstract: Systematists have access to multiple sources of character information in phylogenetic analysis. For example, it is not unusual to have nucleotide sequences from several different genes, or to have molecular and morphological data. How should diverse data be analyzed in phylogenetic analysis? Several methods have been proposed for the treatment of partitioned data: the total evidence, separate analysis, and conditional combination approaches. Here, we review some of the advantages and disadvantages of the different approaches, with special concentration on which methods help us to discern the evolutionary process and provide the most accurate estimates of phylogeny. more

Topics: Phylogenetic network (62%), Phylogenetic tree (53%), Phylogenetics (51%)

843 Citations

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