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Petit E, Silver C, Cornille A, Gladieux P, Rosenthal L, Bruns E, Yee S, Antonovics J, Giraud T, Hood ME. Co-occurrence and hybridization of anther-smut pathogens specialized on Dianthus hosts. Mol Ecol 2017; 26:1877-1890. [PMID: 28231407 DOI: 10.1111/mec.14073] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 01/13/2017] [Accepted: 02/09/2017] [Indexed: 01/05/2023]
Abstract
Host specialization has important consequences for the diversification and ecological interactions of obligate pathogens. The anther-smut disease of natural plant populations, caused by Microbotryum fungi, has been characterized by specialized host-pathogen interactions, which contribute in part to the isolation among these numerous fungal species. This study investigated the molecular variation of Microbotryum pathogens within the geographic and host-specific distributions on wild Dianthus species in southern European Alps. In contrast to prior studies on this pathogen genus, a range of overlapping host specificities was observed for four delineated Microbotryum lineages on Dianthus hosts, and their frequent co-occurrence within single-host populations was quantified at local and regional scales. In addition to potential consequences for direct pathogen competition, the sympatry of Microbotryum lineages led to hybridization between them in many populations, and these admixed genotypes suffered significant meiotic sterility. Therefore, this investigation of the anther-smut fungi reveals how variation in the degrees of host specificity can have major implications for ecological interactions and genetic integrity of differentiated pathogen lineages.
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Affiliation(s)
- Elsa Petit
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA, USA
| | - Casey Silver
- Biology Department, Amherst College, Amherst, MA, 01002, USA
| | - Amandine Cornille
- Center for Adaptation to a Changing Environment, ETH Zürich, 8092, Zürich, Switzerland
| | - Pierre Gladieux
- UMR BGPI, INRA, Campus International de Baillarguet, 34398, Montpellier, France
| | - Lisa Rosenthal
- Biology Department, Amherst College, Amherst, MA, 01002, USA
| | - Emily Bruns
- Department of Biology, University of Virginia, Charlottesville, VA, 22903, USA
| | - Sarah Yee
- Biology Department, Amherst College, Amherst, MA, 01002, USA
| | - Janis Antonovics
- Department of Biology, University of Virginia, Charlottesville, VA, 22903, USA
| | - Tatiana Giraud
- Ecologie Systematique Evolution, CNRS, University of Paris-Sud, AgroParisTech, Université Paris-Saclay, 91400, Orsay, France
| | - Michael E Hood
- Biology Department, Amherst College, Amherst, MA, 01002, USA
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2
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Fortuna TM, Snirc A, Badouin H, Gouzy J, Siguenza S, Esquerre D, Le Prieur S, Shykoff JA, Giraud T. Polymorphic Microsatellite Markers for the Tetrapolar Anther-Smut Fungus Microbotryum saponariae Based on Genome Sequencing. PLoS One 2016; 11:e0165656. [PMID: 27832131 PMCID: PMC5104459 DOI: 10.1371/journal.pone.0165656] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 10/14/2016] [Indexed: 01/06/2023] Open
Abstract
Background Anther-smut fungi belonging to the genus Microbotryum sterilize their host plants by aborting ovaries and replacing pollen by fungal spores. Sibling Microbotryum species are highly specialized on their host plants and they have been widely used as models for studies of ecology and evolution of plant pathogenic fungi. However, most studies have focused, so far, on M. lychnidis-dioicae that parasitizes the white campion Silene latifolia. Microbotryum saponariae, parasitizing mainly Saponaria officinalis, is an interesting anther-smut fungus, since it belongs to a tetrapolar lineage (i.e., with two independently segregating mating-type loci), while most of the anther-smut Microbotryum fungi are bipolar (i.e., with a single mating-type locus). Saponaria officinalis is a widespread long-lived perennial plant species with multiple flowering stems, which makes its anther-smut pathogen a good model for studying phylogeography and within-host multiple infections. Principal Findings Here, based on a generated genome sequence of M. saponariae we developed 6 multiplexes with a total of 22 polymorphic microsatellite markers using an inexpensive and efficient method. We scored these markers in fungal individuals collected from 97 populations across Europe, and found that the number of their alleles ranged from 2 to 11, and their expected heterozygosity from 0.01 to 0.58. Cross-species amplification was examined using nine other Microbotryum species parasitizing hosts belonging to Silene, Dianthus and Knautia genera. All loci were successfully amplified in at least two other Microbotryum species. Significance These newly developed markers will provide insights into the population genetic structure and the occurrence of within-host multiple infections of M. saponariae. In addition, the draft genome of M. saponariae, as well as one of the described markers will be useful resources for studying the evolution of the breeding systems in the genus Microbotryum and the evolution of specialization onto different plant species.
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Affiliation(s)
- Taiadjana M. Fortuna
- Laboratoire d’Ecologie Systématique Evolution, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91400, Orsay, France
- * E-mail:
| | - Alodie Snirc
- Laboratoire d’Ecologie Systématique Evolution, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91400, Orsay, France
| | - Hélène Badouin
- Laboratoire d’Ecologie Systématique Evolution, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91400, Orsay, France
| | - Jérome Gouzy
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, Castanet-Tolosan, F-31326, France
- CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, Castanet-Tolosan, F-31326, France
| | - Sophie Siguenza
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, Castanet-Tolosan, F-31326, France
- CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, Castanet-Tolosan, F-31326, France
| | - Diane Esquerre
- GenPhySE, Université de Toulouse, INRA, INPT, ENVT, Castanet-Tolosan, F-31326, France
| | - Stéphanie Le Prieur
- Laboratoire d’Ecologie Systématique Evolution, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91400, Orsay, France
| | - Jacqui A. Shykoff
- Laboratoire d’Ecologie Systématique Evolution, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91400, Orsay, France
| | - Tatiana Giraud
- Laboratoire d’Ecologie Systématique Evolution, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91400, Orsay, France
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3
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Toh SS, Perlin MH. Resurgence of Less-Studied Smut Fungi as Models of Phytopathogenesis in the Omics Age. PHYTOPATHOLOGY 2016; 106:1244-1254. [PMID: 27111800 DOI: 10.1094/phyto-02-16-0075-rvw] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The smut fungi form a large, diverse, and nonmonophyletic group of plant pathogens that have long served as both important pests of human agriculture and, also, as fertile organisms of scientific investigation. As modern techniques of molecular genetic analysis became available, many previously studied species that proved refractive to these techniques fell by the wayside and were neglected. Now, as the advent of rapid and affordable next-generation sequencing provides genomic and transcriptomic resources for even these "forgotten" fungi, several species are making a comeback and retaking prominent places in phytopathogenic research. In this review, we highlight several of these smut fungi, with special emphasis on Microbotryum lychnidis-dioicae, an anther smut whose molecular genetic tools have finally begun to catch up with its historical importance in classical genetics and now provide mechanistic insights for ecological studies, evolution of host-pathogen interaction, and investigations of emerging infectious disease.
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Affiliation(s)
- Su San Toh
- First and second authors: Department of Biology and Program on Disease Evolution, University of Louisville, Kentucky; and first author: Defence Medical and Environmental Research Institute, DSO National Laboratories, Singapore
| | - Michael H Perlin
- First and second authors: Department of Biology and Program on Disease Evolution, University of Louisville, Kentucky; and first author: Defence Medical and Environmental Research Institute, DSO National Laboratories, Singapore
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4
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Bueker B, Eberlein C, Gladieux P, Schaefer A, Snirc A, Bennett DJ, Begerow D, Hood ME, Giraud T. Distribution and population structure of the anther smut Microbotryum silenes-acaulis parasitizing an arctic-alpine plant. Mol Ecol 2016; 25:811-24. [PMID: 26671732 DOI: 10.1111/mec.13512] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 11/02/2015] [Accepted: 11/26/2015] [Indexed: 12/18/2022]
Abstract
Cold-adapted organisms with current arctic-alpine distributions have persisted during the last glaciation in multiple ice-free refugia, leaving footprints in their population structure that contrast with temperate plants and animals. However, pathogens that live within hosts having arctic-alpine distributions have been little studied. Here, we therefore investigated the geographical range and population structure of a fungus parasitizing an arctic-alpine plant. A total of 1437 herbarium specimens of the plant Silene acaulis were examined, and the anther smut pathogen Microbotryum silenes-acaulis was present throughout the host's geographical range. There was significantly greater incidence of anther smut disease in more northern latitudes and where the host locations were less dense, indicating a major influence of environmental factors and/or host demographic structure on the pathogen distribution. Genetic analyses with seven microsatellite markers on recent collections of 195 M. silenes-acaulis individuals revealed three main genetic clusters, in North America, northern Europe and southern Europe, likely corresponding to differentiation in distinct refugia during the last glaciation. The lower genetic diversity in northern Europe indicates postglacial recolonization northwards from southern refugia. This study combining herbarium surveys and population genetics thus uniquely reveals the effects of climate and environmental factors on a plant pathogen species with an arctic-alpine distribution.
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Affiliation(s)
- Britta Bueker
- Lehrstuhl für Evolution und Biodiversität der Pflanzen, AG Geobotanik, Ruhr-Universität Bochum, Universitätsstraße 150, 44780, Bochum, Germany.,Department of Biology, Amherst College, 220 South Pleasant Street, Amherst, MA, 01002, USA
| | - Chris Eberlein
- Lehrstuhl für Evolution und Biodiversität der Pflanzen, AG Geobotanik, Ruhr-Universität Bochum, Universitätsstraße 150, 44780, Bochum, Germany.,Institut de Biologie Intégrative et des Systèmes, Département de Biologie, PROTEO, Université Laval, Pavillon Charles-Eugène-Marchand, 1030 Avenue de la Médicine, Quebec City, Quebec, Canada, G1V 0A6
| | - Pierre Gladieux
- Ecologie Systématique Evolution, CNRS, Univ. Paris-Sud, AgroParisTech, Université Paris-Saclay, 91400, Orsay, France.,INRA, UMR BGPI, Bâtiment K, Campus International de Baillarguet, F-34398, Montpellier, France.,CIRAD, F-34398, Montpellier, France
| | - Angela Schaefer
- Lehrstuhl für Evolution und Biodiversität der Pflanzen, AG Geobotanik, Ruhr-Universität Bochum, Universitätsstraße 150, 44780, Bochum, Germany
| | - Alodie Snirc
- Ecologie Systématique Evolution, CNRS, Univ. Paris-Sud, AgroParisTech, Université Paris-Saclay, 91400, Orsay, France
| | - Dominic J Bennett
- Ecologie Systématique Evolution, CNRS, Univ. Paris-Sud, AgroParisTech, Université Paris-Saclay, 91400, Orsay, France.,Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Dominik Begerow
- Lehrstuhl für Evolution und Biodiversität der Pflanzen, AG Geobotanik, Ruhr-Universität Bochum, Universitätsstraße 150, 44780, Bochum, Germany
| | - Michael E Hood
- Department of Biology, Amherst College, 220 South Pleasant Street, Amherst, MA, 01002, USA
| | - Tatiana Giraud
- Ecologie Systématique Evolution, CNRS, Univ. Paris-Sud, AgroParisTech, Université Paris-Saclay, 91400, Orsay, France
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5
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Toh SS, Treves DS, Barati MT, Perlin MH. Reliable transformation system for Microbotryum lychnidis-dioicae informed by genome and transcriptome project. Arch Microbiol 2016; 198:813-25. [PMID: 27215216 DOI: 10.1007/s00203-016-1244-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Revised: 05/08/2016] [Accepted: 05/16/2016] [Indexed: 10/21/2022]
Abstract
Microbotryum lychnidis-dioicae is a member of a species complex infecting host plants in the Caryophyllaceae. It is used as a model system in many areas of research, but attempts to make this organism tractable for reverse genetic approaches have not been fruitful. Here, we exploited the recently obtained genome sequence and transcriptome analysis to inform our design of constructs for use in Agrobacterium-mediated transformation techniques currently available for other fungi. Reproducible transformation was demonstrated at the genomic, transcriptional and functional levels. Moreover, these initial proof-of-principle experiments provide evidence that supports the findings from initial global transcriptome analysis regarding expression from the respective promoters under different growth conditions of the fungus. The technique thus provides for the first time the ability to stably introduce transgenes and over-express target M. lychnidis-dioicae genes.
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Affiliation(s)
- Su San Toh
- Department of Biology and Program on Disease Evolution, University of Louisville, Louisville, KY, 40292, USA
| | | | - Michelle T Barati
- Kidney Disease Program, University of Louisville, Louisville, KY, USA
| | - Michael H Perlin
- Department of Biology and Program on Disease Evolution, University of Louisville, Louisville, KY, 40292, USA.
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6
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Buono L, López-Villavicencio M, Shykoff JA, Snirc A, Giraud T. Influence of multiple infection and relatedness on virulence: disease dynamics in an experimental plant population and its castrating parasite. PLoS One 2014; 9:e98526. [PMID: 24892951 PMCID: PMC4043691 DOI: 10.1371/journal.pone.0098526] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 05/02/2014] [Indexed: 11/18/2022] Open
Abstract
The level of parasite virulence, i.e., the decrease in host's fitness due to a pathogen, is expected to depend on several parameters, such as the type of the disease (e.g., castrating or host-killing) and the prevalence of multiple infections. Although these parameters have been extensively studied theoretically, few empirical data are available to validate theoretical predictions. Using the anther smut castrating disease on Silene latifolia caused by Microbotryum lychnidis-dioicae, we studied the dynamics of multiple infections and of different components of virulence (host death, non-recovery and percentage of castrated stems) during the entire lifespan of the host in an experimental population. We monitored the number of fungal genotypes within plants and their relatedness across five years, using microsatellite markers, as well as the rates of recovery and host death in the population. The mean relatedness among genotypes within plants remained at a high level throughout the entire host lifespan despite the dynamics of the disease, with recurrent new infections. Recovery was lower for plants with multiple infections compared to plants infected by a single genotype. As expected for castrating parasites, M. lychnidis-dioicae did not increase host mortality. Mortality varied across years but was generally lower for plants that had been diseased the preceding year. This is one of the few studies to have empirically verified theoretical expectations for castrating parasites, and to show particularly i) that castrated hosts live longer, suggesting that parasites can redirect resources normally used in reproduction to increase host lifespan, lengthening their transmission phase, and ii) that multiple infections increase virulence, here in terms of non-recovery and host castration.
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Affiliation(s)
- Lorenza Buono
- Ecologie, Systématique et Evolution, Université Paris-Sud, Orsay, France
- Ecologie, Systématique et Evolution, CNRS, Orsay, France
| | - Manuela López-Villavicencio
- Department Systématique et Evolution, Origine, Structure, Evolution de la Biodiversité, UMR 7205 CNRS-MNHN, Muséum National d'Histoire Naturelle, Paris, France
| | - Jacqui A. Shykoff
- Ecologie, Systématique et Evolution, Université Paris-Sud, Orsay, France
- Ecologie, Systématique et Evolution, CNRS, Orsay, France
| | - Alodie Snirc
- Ecologie, Systématique et Evolution, Université Paris-Sud, Orsay, France
- Ecologie, Systématique et Evolution, CNRS, Orsay, France
| | - Tatiana Giraud
- Ecologie, Systématique et Evolution, Université Paris-Sud, Orsay, France
- Ecologie, Systématique et Evolution, CNRS, Orsay, France
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7
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GIRAUD T, YOCKTENG R, MARTHEY S, CHIAPELLO H, JONOT O, LOPEZ-VILLAVICENCIO M, DE VIENNE DM, HOOD ME, REFREGIER G, GENDRAULT-JACQUEMARD A, WINCKER P, DOSSAT C. PERMANENT GENETIC RESOURCES: Isolation of 60 polymorphic microsatellite loci in EST libraries of four sibling species of the phytopathogenic fungal complex Microbotryum. Mol Ecol Resour 2008; 8:387-92. [DOI: 10.1111/j.1471-8286.2007.01967.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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8
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Refrégier G, Le Gac M, Jabbour F, Widmer A, Shykoff JA, Yockteng R, Hood ME, Giraud T. Cophylogeny of the anther smut fungi and their caryophyllaceous hosts: prevalence of host shifts and importance of delimiting parasite species for inferring cospeciation. BMC Evol Biol 2008; 8:100. [PMID: 18371215 PMCID: PMC2324105 DOI: 10.1186/1471-2148-8-100] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2007] [Accepted: 03/27/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Using phylogenetic approaches, the expectation that parallel cladogenesis should occur between parasites and hosts has been validated in some studies, but most others provided evidence for frequent host shifts. Here we examine the evolutionary history of the association between Microbotryum fungi that cause anther smut disease and their Caryophyllaceous hosts. We investigated the congruence between host and parasite phylogenies, inferred cospeciation events and host shifts, and assessed whether geography or plant ecology could have facilitated the putative host shifts identified. For cophylogeny analyses on microorganisms, parasite strains isolated from different host species are generally considered to represent independent evolutionary lineages, often without checking whether some strains actually belong to the same generalist species. Such an approach may mistake intraspecific nodes for speciation events and thus bias the results of cophylogeny analyses if generalist species are found on closely related hosts. A second aim of this study was therefore to evaluate the impact of species delimitation on the inferences of cospeciation. RESULTS We inferred a multiple gene phylogeny of anther smut strains from 21 host plants from several geographic origins, complementing a previous study on the delimitation of fungal species and their host specificities. We also inferred a multi-gene phylogeny of their host plants, and the two phylogenies were compared. A significant level of cospeciation was found when each host species was considered to harbour a specific parasite strain, i.e. when generalist parasite species were not recognized as such. This approach overestimated the frequency of cocladogenesis because individual parasite species capable of infecting multiple host species (i.e. generalists) were found on closely related hosts. When generalist parasite species were appropriately delimited and only a single representative of each species was retained, cospeciation events were not more frequent than expected under a random distribution, and many host shifts were inferred.Current geographic distributions of host species seemed to be of little relevance for understanding the putative historical host shifts, because most fungal species had overlapping geographic ranges. We did detect some ecological similarities, including shared pollinators and habitat types, between host species that were diseased by closely related anther smut species. Overall, genetic similarity underlying the host-parasite interactions appeared to have the most important influence on specialization and host-shifts: generalist multi-host parasite species were found on closely related plant species, and related species in the Microbotryum phylogeny were associated with members of the same host clade. CONCLUSION We showed here that Microbotryum species have evolved through frequent host shifts to moderately distant hosts, and we show further that accurate delimitation of parasite species is essential for interpreting cophylogeny studies.
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Affiliation(s)
- Guislaine Refrégier
- Ecologie, Systématique et Evolution, Bâtiment 360, Université Paris-Sud, F-91405 Orsay cedex, France ; CNRS F-91405 Orsay cedex, France
| | - Mickaël Le Gac
- Ecologie, Systématique et Evolution, Bâtiment 360, Université Paris-Sud, F-91405 Orsay cedex, France ; CNRS F-91405 Orsay cedex, France
- Department of Zoology, 6270 University Boulevard, Vancouver BC V6T 1Z4, Canada
| | - Florian Jabbour
- Ecologie, Systématique et Evolution, Bâtiment 360, Université Paris-Sud, F-91405 Orsay cedex, France ; CNRS F-91405 Orsay cedex, France
| | - Alex Widmer
- ETH Zurich, Institute of Integrative Biology, Plant Ecological Genetics, Universitätstr. 16, 8092 Zurich, Switzerland
| | - Jacqui A Shykoff
- Ecologie, Systématique et Evolution, Bâtiment 360, Université Paris-Sud, F-91405 Orsay cedex, France ; CNRS F-91405 Orsay cedex, France
| | - Roxana Yockteng
- Ecologie, Systématique et Evolution, Bâtiment 360, Université Paris-Sud, F-91405 Orsay cedex, France ; CNRS F-91405 Orsay cedex, France
- MNHN UMR 5202, Unité Origine, structure et évolution de la biodiversité, Département Systématique et Evolution, 16 rue Buffon CP 39 75005, France
| | - Michael E Hood
- Department of Biology, McGuire Life Sciences Building, Amherst College, Rts 9 & 116, Amherst, MA 01002-5000, USA
| | - Tatiana Giraud
- Ecologie, Systématique et Evolution, Bâtiment 360, Université Paris-Sud, F-91405 Orsay cedex, France ; CNRS F-91405 Orsay cedex, France
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Dutech C, Enjalbert J, Fournier E, Delmotte F, Barrès B, Carlier J, Tharreau D, Giraud T. Challenges of microsatellite isolation in fungi. Fungal Genet Biol 2007; 44:933-49. [PMID: 17659989 DOI: 10.1016/j.fgb.2007.05.003] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2006] [Revised: 05/04/2007] [Accepted: 05/28/2007] [Indexed: 10/23/2022]
Abstract
Although they represent powerful genetic markers in many fields of biology, microsatellites have been isolated in few fungal species. The aim of this study was to assess whether obtaining microsatellite markers with an acceptable level of polymorphism is generally harder from fungi than in other organisms. We therefore surveyed the number, nature and polymorphism level of published microsatellite markers in fungi from the literature and from our own data on seventeen fungal microsatellite-enriched libraries, and in five other phylogroups (angiosperms, insects, fishes, birds and mammals). Fungal microsatellites indeed appeared both harder to isolate and to exhibit lower polymorphism than in other organisms. This appeared to be due, at least in part, to genomic specificities, such as scarcity and shortness of fungal microsatellite loci. A correlation was observed between mean repeat number and mean allele number in the published fungal microsatellite loci. The cross-species transferability of fungal microsatellites also appeared lower than in other phylogroups. However, microsatellites have been useful in some fungal species. Thus, the considerable advantages of these markers make their development worthwhile, and this study provides some guidelines for their isolation.
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Affiliation(s)
- Cyril Dutech
- INRA, Biodiversité, Gènes et Communautés, 33612, Cestas, France.
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10
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BONO JEREMYM, BLATRIX RUMSAIS, ANTOLIN MICHAELF, HERBERS JOANM. Pirate ants (Polyergus breviceps) and sympatric hosts (Formica occulta and Formica sp. cf. argentea): host specificity and coevolutionary dynamics. Biol J Linn Soc Lond 2007. [DOI: 10.1111/j.1095-8312.2007.00817.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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11
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Koskella B, Giraud T, Hood ME. Pathogen Relatedness Affects the Prevalence of Within‐Host Competition. Am Nat 2006; 168:121-6. [PMID: 16874619 DOI: 10.1086/505770] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2006] [Accepted: 05/09/2006] [Indexed: 11/03/2022]
Abstract
Although the evolutionary consequences of within-host competition among pathogens have been examined extensively, there exists a critical gap in our understanding of factors determining the prevalence of multiple infections. Here we examine the effects of relatedness among strains of the anther-smut pathogen Microbotryum violaceum on the probability of multiple infection in its host, Silene latifolia, after sequential inoculations. We found a significantly higher probability of multiple infection when interacting strains were more closely related, suggesting mechanisms of competitive exclusion that are conditional on genotypic characteristics of the strains involved. Pathogen relatedness therefore determines the prevalence of multiple infection in addition to its outcome, with important consequences for our understanding of virulence evolution and pathogen population structure and diversity.
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Affiliation(s)
- B Koskella
- Department of Biology, Indiana University, Bloomington, IN 47405, USA.
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12
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López-Villavicencio M, Enjalbert J, Hood ME, Shykoff JA, Raquin C, Giraud T. The anther smut disease on Gypsophila repens: a case of parasite sub-optimal performance following a recent host shift? J Evol Biol 2005; 18:1293-303. [PMID: 16135124 DOI: 10.1111/j.1420-9101.2005.00924.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The study of how parasites adapt to new hosts is of great importance for understanding the emergence of new diseases. Here, we report a study of the anther smut disease on Gypsophila repens (Caryophyllaceae). In contrast to what is usually found on other host species, infected natural populations of G. repens are extremely rare. Moreover, symptoms of diseased plants are incomplete and highly variable over the time. These results suggest that the fungus infecting G. repens is a case of a parasite not capable of exploiting its host optimally. Molecular analyses of Microbotryum violaceum strains infecting this and other Caryophyllaceae revealed that this sub-optimal behaviour probably resulted from a recent host shift from the morphologically similar plant Petrorhagia saxifraga. With its exceptionally low virulence and prevalence, but apparent self-sustainability, the disease on G. repens may thus represent an interesting case study for investigating the conditions leading to adaptation of parasites on new hosts.
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13
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Lim S, Notley-McRobb L, Lim M, Carter DA. A comparison of the nature and abundance of microsatellites in 14 fungal genomes. Fungal Genet Biol 2004; 41:1025-36. [PMID: 15465391 DOI: 10.1016/j.fgb.2004.08.004] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2004] [Accepted: 08/06/2004] [Indexed: 11/18/2022]
Abstract
An overview of the character of microsatellites in 14 fungal genomes was obtained by analyzing databases containing complete or nearly complete genome sequences. Low GC content, rather than genome size, was the best predictor of high microsatellite density, although very long iterations of tandem repeats were less common in small genomes. Motif type correlated with %GC in that low-GC genomes were more likely to be dominated by A/T-rich motifs, and vice versa, although some exceptions were noted. The experimentally useful dinucleotide and trinucleotide arrays were analyzed in greater detail. Although these varied in sequence and length among fungal species, some that are likely to be universally useful were identified. This information will be useful for researchers wanting to identify the most useful microsatellites to analyze for the fungi included in this survey and provides a platform for choosing microsatellites to target in fungi that are not yet sequenced.
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Affiliation(s)
- S Lim
- School of Molecular and Microbial Biosciences, University of Sydney, Sydney, Australia
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Giraud T. Patterns of within population dispersal and mating of the fungus Microbotryum violaceum parasitising the plant Silene latifolia. Heredity (Edinb) 2004; 93:559-65. [PMID: 15292913 DOI: 10.1038/sj.hdy.6800554] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
This study explores the patterns of dispersal and mating of the anther smut Microbotryum violaceum, a model species in genetics and evolutionary biology. A French metapopulation of the fungus collected from its caryophyllaceous host Silene latifolia was analysed using microsatellites. The genetic diversity was low, populations were strongly differentiated, and there was no pattern of isolation by distance among populations. There was a strong deficit in heterozygotes, confirming the high self-fertilisation rates suggested by previous studies. Within populations there was a strong pattern of isolation by distance, with identical genotypes being highly clustered. This indicates that fungal spores are dispersed mostly between adjacent plants, and such local dispersal is important for understanding the dynamics and evolution of this disease. Local clusters of identical heterozygous genotypes did not contain significantly fewer individuals than did clusters of homozygous genotypes. As selfing between products of independent meiotic events (intertetrad selfing) rapidly reduces heterozygosity, this suggests that intratetrad matings are frequent, which helps to explain the puzzling maintenance of a sex-ratio distortion in M. violaceum.
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Affiliation(s)
- T Giraud
- Ecologie, Systématique et Evolution, UMR 8079 CNRS-UPS, Bâtiment 360, Université Paris-Sud, F-91405 Orsay cedex, France.
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