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Kupper Q, Prospero S. Microsatellite Genotyping in the Chestnut Blight Fungus Cryphonectria parasitica. Methods Mol Biol 2022; 2536:423-433. [PMID: 35819618 DOI: 10.1007/978-1-0716-2517-0_24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
This chapter describes the use of polymorphic microsatellite (simple sequence repeats, SSR) markers for genotyping isolates of Cryphonectria parasitica, the causal agent of chestnut blight. The SSR presented are particularly useful to characterize the genetic population structure of this invasive fungal pathogen, including invasion history (e.g., possible source population, introduced genotypes) and reproduction mode (sexual vs. asexual). Microsatellite markers can also be used to track fungal strains in laboratory and field experiments.
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Affiliation(s)
- Quirin Kupper
- Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
| | - Simone Prospero
- Swiss Federal Research Institute WSL, Birmensdorf, Switzerland.
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2
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Nuskern L, Tkalec M, Srezović B, Ježić M, Gačar M, Ćurković-Perica M. Laccase Activity in Fungus Cryphonectria parasitica Is Affected by Growth Conditions and Fungal-Viral Genotypic Interactions. J Fungi (Basel) 2021; 7:958. [PMID: 34829245 PMCID: PMC8620238 DOI: 10.3390/jof7110958] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 11/06/2021] [Accepted: 11/08/2021] [Indexed: 11/16/2022] Open
Abstract
Laccase activity reduction in the chestnut blight fungus Cryphonectria parasitica usually accompanies the hypovirulence caused by the infection of fungus with Cryphonectria hypovirus 1 (CHV1). However, the different methods utilized for assessing this phenomenon has produced varied and often conflicting results. Furthermore, the majority of experimental setups included only one prototypic system, further confounding the results. Considering the diversity of fungal isolates, viral strains, and variability of their effects on the phytopathogenic process observed in nature, our goal was to ascertain if laccase activity variability is affected by (1) different C. parasitica isolates infected with several CHV1 strains, and (2) growth conditions. We have demonstrated that some CHV1 strains, contrary to previous assumptions, increase the activity of C. parasitica laccases. The specific fungal isolates used in the experiments and culture conditions also affected the results. Furthermore, we showed that two commonly used laccase substrates, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) and 2,4-dimethoxyphenol, cannot be used interchangeably in C. parasitica laccase activity measurements. Our results illustrate the importance of conducting this type of study in experimental systems and culture conditions that resemble natural conditions as much as possible to be able to infer the most relevant conclusions applicable to natural populations.
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Affiliation(s)
- Lucija Nuskern
- Department of Biology, Division of Microbiology, Faculty of Science, University of Zagreb, Marulićev trg 9a, 10000 Zagreb, Croatia; (L.N.); (B.S.); (M.J.); (M.G.)
| | - Mirta Tkalec
- Department of Biology, Division of Botany, Faculty of Science, University of Zagreb, Rooseveltov trg 6, 10000 Zagreb, Croatia;
| | - Bruno Srezović
- Department of Biology, Division of Microbiology, Faculty of Science, University of Zagreb, Marulićev trg 9a, 10000 Zagreb, Croatia; (L.N.); (B.S.); (M.J.); (M.G.)
| | - Marin Ježić
- Department of Biology, Division of Microbiology, Faculty of Science, University of Zagreb, Marulićev trg 9a, 10000 Zagreb, Croatia; (L.N.); (B.S.); (M.J.); (M.G.)
| | - Martina Gačar
- Department of Biology, Division of Microbiology, Faculty of Science, University of Zagreb, Marulićev trg 9a, 10000 Zagreb, Croatia; (L.N.); (B.S.); (M.J.); (M.G.)
| | - Mirna Ćurković-Perica
- Department of Biology, Division of Microbiology, Faculty of Science, University of Zagreb, Marulićev trg 9a, 10000 Zagreb, Croatia; (L.N.); (B.S.); (M.J.); (M.G.)
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Ježić M, Schwarz JM, Prospero S, Sotirovski K, Risteski M, Ćurković-Perica M, Nuskern L, Krstin L, Katanić Z, Maleničić E, Poljak I, Idžojtić M, Rigling D. Temporal and Spatial Genetic Population Structure of Cryphonectria parasitica and Its Associated Hypovirus Across an Invasive Range of Chestnut Blight in Europe. Phytopathology 2021; 111:1327-1337. [PMID: 33417482 DOI: 10.1094/phyto-09-20-0405-r] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Chestnut blight has spread throughout Europe since the introduction of its causal agent, Cryphonectria parasitica, >70 years ago. In our study, we analyzed the diversity of vegetative compatibility (vc) and microsatellite genotypes of C. parasitica, as well as sequence diversity of Cryphonectria hypovirus 1 (CHV1) in six populations from Switzerland, Croatia, and North Macedonia. Resampling of local populations that were already investigated more than a decade ago allowed us to analyze the spatial and temporal population structure across an invasive range of the pathogen in Europe. Regardless of which genetic marker was used, the >60-year-old Swiss and Croatian populations had high population diversity, whereas more recent North Macedonian populations were mostly clonal. These diversity differences between the investigated populations remained stable over time. A high diversity of CHV1 was observed in all three countries, with North Macedonian strains forming a separate cluster from strains obtained in other countries. No correlation between vc diversity and CHV1 prevalence was observed, suggesting a well-established and maintained natural hypovirulence in all countries, further corroborated by an observed increase in genetic diversity of Croatian C. parasitica populations over time, without collapse of CHV1 prevalence.
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Affiliation(s)
- Marin Ježić
- University of Zagreb, Faculty of Science, Department of Biology, Division of Microbiology, Zagreb, Croatia
| | | | - Simone Prospero
- Swiss Federal Research Institute WSL, 8903 Birmensdorf, Switzerland
| | - Kiril Sotirovski
- Ss Cyril and Methodius University in Skopje, Hans Em Faculty of Forest Sciences, Landscape Architecture and Environmental Engineering, 1000 Skopje, North Macedonia
| | - Mihajlo Risteski
- Ss Cyril and Methodius University in Skopje, Hans Em Faculty of Forest Sciences, Landscape Architecture and Environmental Engineering, 1000 Skopje, North Macedonia
| | - Mirna Ćurković-Perica
- University of Zagreb, Faculty of Science, Department of Biology, Division of Microbiology, Zagreb, Croatia
| | - Lucija Nuskern
- University of Zagreb, Faculty of Science, Department of Biology, Division of Microbiology, Zagreb, Croatia
| | - Ljiljana Krstin
- University J. J. Strossmayer of Osijek, Department of Biology, 31000 Osijek, Croatia
| | - Zorana Katanić
- University J. J. Strossmayer of Osijek, Department of Biology, 31000 Osijek, Croatia
| | - Ema Maleničić
- University of Zagreb, Faculty of Science, Department of Biology, Division of Microbiology, Zagreb, Croatia
| | - Igor Poljak
- University of Zagreb, Faculty of Forestry and Wood Technology, Department of Forest Genetics, Dendrology and Botany, 10000 Zagreb, Croatia
| | - Marilena Idžojtić
- University of Zagreb, Faculty of Forestry and Wood Technology, Department of Forest Genetics, Dendrology and Botany, 10000 Zagreb, Croatia
| | - Daniel Rigling
- Swiss Federal Research Institute WSL, 8903 Birmensdorf, Switzerland
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Skrede I, Murat C, Hess J, Maurice S, Sønstebø JH, Kohler A, Barry-Etienne D, Eastwood D, Högberg N, Martin F, Kauserud H. Contrasting demographic histories revealed in two invasive populations of the dry rot fungus Serpula lacrymans. Mol Ecol 2021; 30:2772-2789. [PMID: 33955084 DOI: 10.1111/mec.15934] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 04/15/2021] [Accepted: 04/19/2021] [Indexed: 12/21/2022]
Abstract
Globalization and international trade have impacted organisms around the world leading to a considerable number of species establishing in new geographic areas. Many organisms have taken advantage of human-made environments, including buildings. One such species is the dry rot fungus Serpula lacrymans, which is the most aggressive wood-decay fungus in indoor environments in temperate regions. Using population genomic analyses of 36 full genome sequenced isolates, we demonstrated that European and Japanese isolates are highly divergent and the populations split 3000-19,000 generations ago, probably predating human influence. Approximately 250 generations ago, the European population went through a tight bottleneck, probably corresponding to the fungus colonization of the built environment in Europe. The demographic history of these populations, probably lead to low adaptive potential. Only two loci under selection were identified using a Fst outlier approach, and selective sweep analyses identified three loci with extended haplotype homozygosity. The selective sweep analyses found signals in genes possibly related to decay of various substrates in Japan and in genes involved DNA replication and protein modification in Europe. Our results suggest that the dry rot fungus independently established in indoor environments in Europe and Japan and that invasive species can potentially establish large populations in new habitats based on a few colonizing individuals.
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Affiliation(s)
- Inger Skrede
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Claude Murat
- INRAE, UMR Interactions Arbres/Microorganismes, Centre INRAE-GrandEst Lorraine, Université de Lorraine, Champenoux, France
| | - Jaqueline Hess
- Department of Biosciences, University of Oslo, Oslo, Norway.,University of Vienna, Vienna, Austria
| | - Sundy Maurice
- Department of Biosciences, University of Oslo, Oslo, Norway
| | | | - Annegret Kohler
- INRAE, UMR Interactions Arbres/Microorganismes, Centre INRAE-GrandEst Lorraine, Université de Lorraine, Champenoux, France
| | | | - Dan Eastwood
- Department of Biosciences, University of Swansea, Swansea, UK
| | - Nils Högberg
- Department of Forest Mycology and Plant Pathology, Swedish Agricultural University, Uppsala, Sweden
| | - Francis Martin
- INRAE, UMR Interactions Arbres/Microorganismes, Centre INRAE-GrandEst Lorraine, Université de Lorraine, Champenoux, France.,Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Institute of Microbiology, Beijing Forestry University, Beijing, China
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Kranjec Orlović J, Drvodelić D, Vukelić M, Rukavina M, Diminić D, Oršanić M. Impact of Thermotherapy and Short-Term Storage on Quercus robur L. Acorn Mycobiota and Germination. Forests 2021; 12:528. [DOI: 10.3390/f12050528] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
When natural regeneration of Quercus robur stands is hampered by an insufficient acorn yield, human assisted sowing of acorns collected in non-affected stands and stored for some period of time is performed. To inhibit the development of fungi and acorn deterioration during storage, thermotherapy is usually applied by submerging acorns for 2.5 h in water heated to 41 °C. This research aimed to test the effect of four thermotherapy treatments of different durations and/or applied temperatures as well as short-term storage at −1 °C or 3 °C on acorn internal mycobiota and germination. Fungal presence in cotyledons was analyzed in 450 acorns by isolation of mycelia on artificial media, followed by a DNA-based identification. Germination of 2000 acorns was monitored in an open field trial. Thermotherapy significantly decreased fungal diversity, while storage at 3 °C increased the isolation frequency of several fungi, mainly Penicillium spp. The most frequently isolated fungi did not show a negative impact on acorn germination after short-term storage. The study confirmed the efficiency of thermotherapy in the eradication of a part of acorn internal mycobiota, but also its effect on the proliferation of fast-colonizing fungi during storage. However, the latter showed to be more stimulated by storage conditions, specifically by storage at 3 °C.
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Stauber L, Badet T, Feurtey A, Prospero S, Croll D. Emergence and diversification of a highly invasive chestnut pathogen lineage across southeastern Europe. eLife 2021; 10:e56279. [PMID: 33666552 PMCID: PMC7935491 DOI: 10.7554/elife.56279] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Accepted: 02/17/2021] [Indexed: 12/18/2022] Open
Abstract
Invasive microbial species constitute a major threat to biodiversity, agricultural production and human health. Invasions are often dominated by one or a small number of genotypes, yet the underlying factors driving invasions are poorly understood. The chestnut blight fungus Cryphonectria parasitica first decimated the North American chestnut, and a more recent outbreak threatens European chestnut stands. To unravel the chestnut blight invasion of southeastern Europe, we sequenced 230 genomes of predominantly European strains. Genotypes outside of the invasion zone showed high levels of diversity with evidence for frequent and ongoing recombination. The invasive lineage emerged from the highly diverse European genotype pool rather than a secondary introduction from Asia or North America. The expansion across southeastern Europe was mostly clonal and is dominated by a single mating type, suggesting a fitness advantage of asexual reproduction. Our findings show how an intermediary, highly diverse bridgehead population gave rise to an invasive, largely clonally expanding pathogen.
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Affiliation(s)
- Lea Stauber
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL)BirmensdorfSwitzerland
- Laboratory of Evolutionary Genetics, Institute of Biology, University of NeuchâtelNeuchâtelSwitzerland
| | - Thomas Badet
- Laboratory of Evolutionary Genetics, Institute of Biology, University of NeuchâtelNeuchâtelSwitzerland
| | - Alice Feurtey
- Laboratory of Evolutionary Genetics, Institute of Biology, University of NeuchâtelNeuchâtelSwitzerland
- Plant Pathology, Institute of Integrative Biology, ETH ZürichZürichSwitzerland
| | - Simone Prospero
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL)BirmensdorfSwitzerland
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of NeuchâtelNeuchâtelSwitzerland
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Krstin L, Katanić Z, Repar J, Ježić M, Kobaš A, Ćurković-Perica M. Genetic Diversity of Cryphonectria hypovirus 1, a Biocontrol Agent of Chestnut Blight, in Croatia and Slovenia. Microb Ecol 2020; 79:148-163. [PMID: 31053974 DOI: 10.1007/s00248-019-01377-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 04/03/2019] [Indexed: 06/09/2023]
Abstract
Transmissible hypovirulence associated with Cryphonectria hypovirus 1 (CHV1) has been used for biological control of chestnut blight, devastating disease of chestnut caused by the fungus Cryphonectria parasitica. The main aims of this study were to provide molecular characterization of CHV1 from Croatia and Slovenia and to reveal its genetic variability, phylogeny, and diversification of populations. Fifty-one CHV1 haplotypes were detected among 54 partially sequenced CHV1 isolates, all belonging to Italian subtype (I). Diversity was mainly generated by point mutations while evidence of recombination was not found. The level of conservation over analyzed parts of ORF-A proteins p29 and p40 varied, but functional sites were highly conserved. Phylogenetic analysis revealed close relatedness and intermixing of Croatian and Slovenian CHV1 populations. Our CHV1 isolates were also related to Swiss and Bosnian hypoviruses supporting previously suggested course of CHV1 invasion in Europe. Overall, this study indicates that phylogeny of CHV1 subtype I in Europe is complex and characterized with frequent point mutations resulting in many closely related variants of the virus. Possible association between variations within CHV1 ORF-A and growth of the hypovirulent fungal isolates is tested and presented.
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Affiliation(s)
- Ljiljana Krstin
- Department of Biology, Josip Juraj Strossmayer University of Osijek, HR-31000, Osijek, Croatia
| | - Zorana Katanić
- Department of Biology, Josip Juraj Strossmayer University of Osijek, HR-31000, Osijek, Croatia
| | - Jelena Repar
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Marin Ježić
- Department of Biology, Faculty of Science, University of Zagreb, HR-10000, Zagreb, Croatia
| | - Ana Kobaš
- Department of Biology, Josip Juraj Strossmayer University of Osijek, HR-31000, Osijek, Croatia
| | - Mirna Ćurković-Perica
- Department of Biology, Faculty of Science, University of Zagreb, HR-10000, Zagreb, Croatia.
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8
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Vuković R, Liber Z, Ježić M, Sotirovski K, Ćurković-Perica M. Link between epigenetic diversity and invasive status of south-eastern European populations of phytopathogenic fungus Cryphonectria parasitica. Environ Microbiol 2019; 21:4521-4536. [PMID: 31314941 DOI: 10.1111/1462-2920.14742] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 07/12/2019] [Accepted: 07/15/2019] [Indexed: 12/14/2022]
Abstract
Epigenetic modifications may play an important role in invasion and adaptation of clonal and invasive populations to different environments. The aim of this study was to analyse epigenetic diversity and structure within and among populations of invasive pathogenic fungus Cryphonectria parasitica from south-eastern Europe, where one haplotype S12 dominates. The highest level of epigenetic diversity was found in haplotype S1, followed by S2, while the lowest level of epigenetic diversity was found in haplotype S12. Similar pattern of epigenetic diversity was detected in the control, genetically diverse Croatian population where S1 haplotype dominates. In four south-eastern European populations, the highest level of epigenetic diversity was observed in the Italian population, the oldest population in the studied area, while the lowest diversity was found in most recently established Bulgarian population. This relationship between epigenetic diversity and population age implies the important role of epigenetic modifications on the process of invasion. Our data suggest that epigenetic differences might affect the success of expansion of certain haplotype into new regions. Understanding the role of epigenetic processes in expansion and (pre)adaptation of fungal plant pathogens, besides fundamental knowledge, can contribute to development of strategies for control of fungal spread and pathogenesis.
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Affiliation(s)
- Rosemary Vuković
- Department of Biology, J. J. Strossmayer University of Osijek, Osijek, Croatia
| | - Zlatko Liber
- Department of Biology, Faculty of Science, University of Zagreb, Zagreb, Croatia.,Centre of Excellence for Biodiversity and Molecular Plant Breeding, Zagreb, Croatia
| | - Marin Ježić
- Department of Biology, Faculty of Science, University of Zagreb, Zagreb, Croatia
| | - Kiril Sotirovski
- Faculty of Forestry, Ss. Cyril and Methodius University of Skopje, Skopje, North Macedonia
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Rigling D, Borst N, Cornejo C, Supatashvili A, Prospero S. Genetic and Phenotypic Characterization of Cryphonectria hypovirus 1 from Eurasian Georgia. Viruses 2018; 10:v10120687. [PMID: 30513977 PMCID: PMC6315935 DOI: 10.3390/v10120687] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 11/30/2018] [Accepted: 11/30/2018] [Indexed: 01/18/2023] Open
Abstract
Cryphonectria hypovirus 1 (CHV-1) infects the chestnut blight fungus Cryphonectria parasitica and acts as a biological control agent against this harmful tree disease. In this study, we screened the recently characterized C. parasitica population in Eurasian Georgia for the presence of CHV-1. We found 62 CHV-1 infected C. parasitica isolates (9.3%) among a total of 664 isolates sampled in 14 locations across Georgia. The prevalence of CHV-1 at the different locations ranged from 0% in the eastern part of the country to 29% in the western part. Sequencing of two specific regions of the viral genome one each in ORFA and ORFB revealed a unique CHV-1 subtype in Georgia. This subtype has a recombinant pattern combining the ORFA region from the subtype F2 and the ORFB region from subtype D. All 62 viral strains belonged to this Georgian CHV-1 subtype (subtype G). The CHV-1 subtype G strongly reduced the parasitic growth of C. parasitica isolates from Georgia, with a more severe effect on the European genepool compared to the Georgian genepool. The CHV-1 subtype detected in Georgia provides a valuable candidate for biological control applications in the Caucasus region.
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Affiliation(s)
- Daniel Rigling
- WSL Swiss Federal Research Institute, Zürcherstrasse 111, 8903 Birmensdorf; Switzerland.
| | - Nora Borst
- WSL Swiss Federal Research Institute, Zürcherstrasse 111, 8903 Birmensdorf; Switzerland.
| | - Carolina Cornejo
- WSL Swiss Federal Research Institute, Zürcherstrasse 111, 8903 Birmensdorf; Switzerland.
| | - Archil Supatashvili
- Vasil Gulisashvili Forestry Institute, Agricultural University of Georgia, 0186 Tbilisi, Georgia.
| | - Simone Prospero
- WSL Swiss Federal Research Institute, Zürcherstrasse 111, 8903 Birmensdorf; Switzerland.
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Ježić M, Mlinarec J, Vuković R, Katanić Z, Krstin L, Nuskern L, Poljak I, Idžojtić M, Tkalec M, Ćurković-Perica M. Changes in Cryphonectria parasitica Populations Affect Natural Biological Control of Chestnut Blight. Phytopathology 2018; 108:870-877. [PMID: 29442579 DOI: 10.1094/phyto-07-17-0252-r] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Invasive species, especially plant pathogens, have a potential to completely eradicate native plant species and remodel landscapes. Tripartite interactions among sweet chestnut (Castanea sativa), chestnut blight-causing invasive fungus Cryphonectria parasitica, and hyperparasitic virus Cryphonectria hypovirus 1 (CHV1) were studied in two populations. The number of different vegetative compatibility (vc) types of C. parasitica more than doubled over the 10 years, while the hypovirulence incidence dropped in one population and slightly increased in the other one. Over the course of our 3-year monitoring experiment, the prevalence of hypovirulent isolates obtained from monitored cankers increased slowly (i.e., more hypovirulent isolates were being obtained from the same cankers over time). Within studied cankers, considerable changes in vc type and CHV1 presence were observed, indicating a highly dynamic system in which virulent and hypovirulent mycelia, sometimes of discordant vc types, often appeared together. The increase in hypovirulence prevalence did not have any observable curative effect on the cankers and, occasionally, reactivation of healed cankers by new, virulent C. parasitica isolates was observed. Both short- and long-term observations and revalidation of the infected plant populations are necessary to accurately estimate disease progress and formulate an adequate disease management strategy.
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Affiliation(s)
- Marin Ježić
- First, second, sixth, and tenth authors: University of Zagreb, Faculty of Science, Department of Biology, Division of Microbiology, Marulicev trg 9a, Zagreb, Croatia; third, fourth, and fifth authors: J. J. Strossmayer University of Osijek, Department of Biology, Cara Hadrijana 8A, Osijek, Croatia; seventh and eighth authors: University of Zagreb, Faculty of Forestry, Department of forest genetics and dendrology, Svetosimunska 25, Zagreb, Croatia; and ninth author: University of Zagreb, Faculty of Science, Department of Biology, Division of Botany, Rooseveltov trg 6, Zagreb, Croatia
| | - Jelena Mlinarec
- First, second, sixth, and tenth authors: University of Zagreb, Faculty of Science, Department of Biology, Division of Microbiology, Marulicev trg 9a, Zagreb, Croatia; third, fourth, and fifth authors: J. J. Strossmayer University of Osijek, Department of Biology, Cara Hadrijana 8A, Osijek, Croatia; seventh and eighth authors: University of Zagreb, Faculty of Forestry, Department of forest genetics and dendrology, Svetosimunska 25, Zagreb, Croatia; and ninth author: University of Zagreb, Faculty of Science, Department of Biology, Division of Botany, Rooseveltov trg 6, Zagreb, Croatia
| | - Rosemary Vuković
- First, second, sixth, and tenth authors: University of Zagreb, Faculty of Science, Department of Biology, Division of Microbiology, Marulicev trg 9a, Zagreb, Croatia; third, fourth, and fifth authors: J. J. Strossmayer University of Osijek, Department of Biology, Cara Hadrijana 8A, Osijek, Croatia; seventh and eighth authors: University of Zagreb, Faculty of Forestry, Department of forest genetics and dendrology, Svetosimunska 25, Zagreb, Croatia; and ninth author: University of Zagreb, Faculty of Science, Department of Biology, Division of Botany, Rooseveltov trg 6, Zagreb, Croatia
| | - Zorana Katanić
- First, second, sixth, and tenth authors: University of Zagreb, Faculty of Science, Department of Biology, Division of Microbiology, Marulicev trg 9a, Zagreb, Croatia; third, fourth, and fifth authors: J. J. Strossmayer University of Osijek, Department of Biology, Cara Hadrijana 8A, Osijek, Croatia; seventh and eighth authors: University of Zagreb, Faculty of Forestry, Department of forest genetics and dendrology, Svetosimunska 25, Zagreb, Croatia; and ninth author: University of Zagreb, Faculty of Science, Department of Biology, Division of Botany, Rooseveltov trg 6, Zagreb, Croatia
| | - Ljiljana Krstin
- First, second, sixth, and tenth authors: University of Zagreb, Faculty of Science, Department of Biology, Division of Microbiology, Marulicev trg 9a, Zagreb, Croatia; third, fourth, and fifth authors: J. J. Strossmayer University of Osijek, Department of Biology, Cara Hadrijana 8A, Osijek, Croatia; seventh and eighth authors: University of Zagreb, Faculty of Forestry, Department of forest genetics and dendrology, Svetosimunska 25, Zagreb, Croatia; and ninth author: University of Zagreb, Faculty of Science, Department of Biology, Division of Botany, Rooseveltov trg 6, Zagreb, Croatia
| | - Lucija Nuskern
- First, second, sixth, and tenth authors: University of Zagreb, Faculty of Science, Department of Biology, Division of Microbiology, Marulicev trg 9a, Zagreb, Croatia; third, fourth, and fifth authors: J. J. Strossmayer University of Osijek, Department of Biology, Cara Hadrijana 8A, Osijek, Croatia; seventh and eighth authors: University of Zagreb, Faculty of Forestry, Department of forest genetics and dendrology, Svetosimunska 25, Zagreb, Croatia; and ninth author: University of Zagreb, Faculty of Science, Department of Biology, Division of Botany, Rooseveltov trg 6, Zagreb, Croatia
| | - Igor Poljak
- First, second, sixth, and tenth authors: University of Zagreb, Faculty of Science, Department of Biology, Division of Microbiology, Marulicev trg 9a, Zagreb, Croatia; third, fourth, and fifth authors: J. J. Strossmayer University of Osijek, Department of Biology, Cara Hadrijana 8A, Osijek, Croatia; seventh and eighth authors: University of Zagreb, Faculty of Forestry, Department of forest genetics and dendrology, Svetosimunska 25, Zagreb, Croatia; and ninth author: University of Zagreb, Faculty of Science, Department of Biology, Division of Botany, Rooseveltov trg 6, Zagreb, Croatia
| | - Marilena Idžojtić
- First, second, sixth, and tenth authors: University of Zagreb, Faculty of Science, Department of Biology, Division of Microbiology, Marulicev trg 9a, Zagreb, Croatia; third, fourth, and fifth authors: J. J. Strossmayer University of Osijek, Department of Biology, Cara Hadrijana 8A, Osijek, Croatia; seventh and eighth authors: University of Zagreb, Faculty of Forestry, Department of forest genetics and dendrology, Svetosimunska 25, Zagreb, Croatia; and ninth author: University of Zagreb, Faculty of Science, Department of Biology, Division of Botany, Rooseveltov trg 6, Zagreb, Croatia
| | - Mirta Tkalec
- First, second, sixth, and tenth authors: University of Zagreb, Faculty of Science, Department of Biology, Division of Microbiology, Marulicev trg 9a, Zagreb, Croatia; third, fourth, and fifth authors: J. J. Strossmayer University of Osijek, Department of Biology, Cara Hadrijana 8A, Osijek, Croatia; seventh and eighth authors: University of Zagreb, Faculty of Forestry, Department of forest genetics and dendrology, Svetosimunska 25, Zagreb, Croatia; and ninth author: University of Zagreb, Faculty of Science, Department of Biology, Division of Botany, Rooseveltov trg 6, Zagreb, Croatia
| | - Mirna Ćurković-Perica
- First, second, sixth, and tenth authors: University of Zagreb, Faculty of Science, Department of Biology, Division of Microbiology, Marulicev trg 9a, Zagreb, Croatia; third, fourth, and fifth authors: J. J. Strossmayer University of Osijek, Department of Biology, Cara Hadrijana 8A, Osijek, Croatia; seventh and eighth authors: University of Zagreb, Faculty of Forestry, Department of forest genetics and dendrology, Svetosimunska 25, Zagreb, Croatia; and ninth author: University of Zagreb, Faculty of Science, Department of Biology, Division of Botany, Rooseveltov trg 6, Zagreb, Croatia
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11
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Krstin L, Katanić Z, Ježić M, Poljak I, Nuskern L, Matković I, Idžojtić M, Ćurković-Perica M. Biological control of chestnut blight in Croatia: an interaction between host sweet chestnut, its pathogen Cryphonectria parasitica and the biocontrol agent Cryphonectria hypovirus 1. Pest Manag Sci 2017; 73:582-589. [PMID: 27288259 DOI: 10.1002/ps.4335] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 06/07/2016] [Accepted: 06/08/2016] [Indexed: 06/06/2023]
Abstract
BACKGROUND Chestnut blight, caused by the fungus Cryphonectria parasitica, is a severe chestnut disease that can be controlled with naturally occurring hypoviruses in many areas of Europe. The aim of this research was to measure the effect of different Cryphonectria hypovirus 1 (CHV1) strains on the growth of the fungal host and select strains that could potentially be used for human-mediated biocontrol in forests and orchards, and to investigate whether and how chestnut-fungus-virus interactions affect the development and growth of the lesion area on cut stems. RESULTS Two Croatian CHV1 strains (CR23 and M56/1) were selected as potential biocontrol agents. The sequencing of CHV1/ORF-A showed that both of these virus strains belonged to the Italian subtype of CHV1. In vitro transfection of selected virus strains from hypovirulent to genetically diverse virus-free fungal isolates and subsequent inoculation of all virus/fungus combinations on stems of genetically diverse sweet chestnut trees revealed that Croatian virus strain CR23 had an equally hypovirulent effect on the host as the strong French strain CHV1-EP713, while M56/1 had a weaker effect. Furthermore, it was shown that in some cases the same hypovirus/fungus combinations induced various degrees of canker development on different chestnut genotypes. CONCLUSION Some CHV1 strains belonging to the Italian subtype have similar hypovirulent effects on C. parasitica to those belonging to the French subtype. Furthermore, chestnut susceptibility and recovery could be influenced by the response of chestnut trees to particular hypovirulent C. parasitica isolates, and virus-fungus-chestnut interactions could have significant implications for the success of chestnut blight biocontrol. © 2016 Society of Chemical Industry.
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Affiliation(s)
- Ljiljana Krstin
- Department of Biology, University of J. J. Strossmayer in Osijek, Osijek, Croatia
| | - Zorana Katanić
- Department of Biology, University of J. J. Strossmayer in Osijek, Osijek, Croatia
| | - Marin Ježić
- Division of Biology, Faculty of Science, University of Zagreb, Zagreb, Croatia
| | - Igor Poljak
- Department of Forest Genetics, Dendrology and Botany, Faculty of Forestry, University of Zagreb, Zagreb, Croatia
| | - Lucija Nuskern
- Division of Biology, Faculty of Science, University of Zagreb, Zagreb, Croatia
| | - Ivana Matković
- Department of Biology, University of J. J. Strossmayer in Osijek, Osijek, Croatia
| | - Marilena Idžojtić
- Department of Forest Genetics, Dendrology and Botany, Faculty of Forestry, University of Zagreb, Zagreb, Croatia
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12
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Jeger M, Bragard C, Chatzivassiliou E, Dehnen‐Schmutz K, Gilioli G, Jaques Miret JA, MacLeod A, Navajas Navarro M, Niere B, Parnell S, Potting R, Rafoss T, Urek G, Van Bruggen A, Van der Werf W, West J, Winter S, Maresi G, Prospero S, Vettraino AM, Vloutoglou I, Pautasso M, Rossi V. Risk assessment and reduction options for Cryphonectria parasitica in the EU. EFSA J 2016. [DOI: 10.2903/j.efsa.2016.4641] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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13
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Ashu EE, Xu J. The roles of sexual and asexual reproduction in the origin and dissemination of strains causing fungal infectious disease outbreaks. Infect Genet Evol 2015; 36:199-209. [PMID: 26394109 DOI: 10.1016/j.meegid.2015.09.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 09/16/2015] [Accepted: 09/18/2015] [Indexed: 12/15/2022]
Abstract
Sexual reproduction commonly refers to the reproductive process in which genomes from two sources are combined into a single cell through mating and then the zygote genomes are partitioned to progeny cells through meiosis. Reproduction in the absence of mating and meiosis is referred to as asexual or clonal reproduction. One major advantage of sexual reproduction is that it generates genetic variation among progeny which may allow for faster adaptation of the population to novel and/or stressful environments. However, adaptation to stressful or new environments can still occur through mutation, in the absence of sex. In this review, we analyzed the relative contributions of sexual and asexual reproduction in the origin and spread of strains causing fungal infectious diseases outbreaks. The necessity of sex and the ability of asexual fungi to initiate outbreaks are discussed. We propose a framework that relates the modes of reproduction to the origin and propagation of fungal disease outbreaks. Our analyses suggest that both sexual and asexual reproduction can play critical roles in the origin of outbreak strains and that the rapid spread of outbreak strains is often accomplished through asexual expansion.
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Affiliation(s)
- Eta Ebasi Ashu
- Department of Biology, McMaster University, 1280 Main St. W, Hamilton, ON L8S 4K1, Canada
| | - Jianping Xu
- Department of Biology, McMaster University, 1280 Main St. W, Hamilton, ON L8S 4K1, Canada.
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14
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Short DP, Double M, Nuss DL, Stauder CM, MacDonald W, Kasson MT. Multilocus PCR Assays Elucidate Vegetative Incompatibility Gene Profiles of Cryphonectria parasitica in the United States. Appl Environ Microbiol 2015; 81:5736-42. [PMID: 26070681 DOI: 10.1128/AEM.00926-15] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 06/08/2015] [Indexed: 11/20/2022] Open
Abstract
Chestnut blight is a devastating disease of Castanea spp. Mycoviruses that reduce virulence (hypovirulence) of the causative agent, Cryphonectria parasitica, can be used to manage chestnut blight. However, vegetative incompatibility (vic) barriers that restrict anastomosis-mediated virus transmission hamper hypovirulence efficacy. In order to effectively determine the vegetative incompatibility genetic structure of C. parasitica field populations, we have designed PCR primer sets that selectively amplify and distinguish alleles for each of the six known diallelic C. parasitica vic genetic loci. PCR assay results were validated using a panel of 64 European tester strains with genetically determined vic genotypes. Analysis of 116 C. parasitica isolates collected from five locations in the eastern United States revealed 39 unique vic genotypes and generally good agreement between PCR and tester strain coculturing assays in terms of vic diversity and genotyping. However, incongruences were observed for isolates from multiple locations and suggested that the coculturing assay can overestimate diversity at the six known vic loci. The availability of molecular tools for rapid and precise vic genotyping significantly improves the ability to predict and evaluate the efficacy of hypovirulence and related management strategies.
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Abstract
Forest pathology, the science of forest health and tree diseases, is operating in a rapidly developing environment. Most importantly, global trade and climate change are increasing the threat to forest ecosystems posed by new diseases. Various studies relevant to forest pathology in a changing world are accumulating, thus making it necessary to provide an update of recent literature. In this contribution, we summarize research at the interface between forest pathology and landscape ecology, biogeography, global change science and research on tree endophytes. Regional outbreaks of tree diseases are requiring interdisciplinary collaboration, e.g. between forest pathologists and landscape ecologists. When tree pathogens are widely distributed, the factors determining their broad-scale distribution can be studied using a biogeographic approach. Global change, the combination of climate and land use change, increased pollution, trade and urbanization, as well as invasive species, will influence the effects of forest disturbances such as wildfires, droughts, storms, diseases and insect outbreaks, thus affecting the health and resilience of forest ecosystems worldwide. Tree endophytes can contribute to biological control of infectious diseases, enhance tolerance to environmental stress or behave as opportunistic weak pathogens potentially competing with more harmful ones. New molecular techniques are available for studying the complete tree endobiome under the influence of global change stressors from the landscape to the intercontinental level. Given that exotic tree diseases have both ecologic and economic consequences, we call for increased interdisciplinary collaboration in the coming decades between forest pathologists and researchers studying endophytes with tree geneticists, evolutionary and landscape ecologists, biogeographers, conservation biologists and global change scientists and outline interdisciplinary research gaps.
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Affiliation(s)
- Marco Pautasso
- Forest Pathology & Dendrology, Institute of Integrative Biology (IBZ), ETH Zurich, 8092, Zurich, Switzerland,
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16
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Gladieux P, Feurtey A, Hood ME, Snirc A, Clavel J, Dutech C, Roy M, Giraud T. The population biology of fungal invasions. Mol Ecol 2015; 24:1969-86. [DOI: 10.1111/mec.13028] [Citation(s) in RCA: 142] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 11/24/2014] [Accepted: 11/28/2014] [Indexed: 12/16/2022]
Affiliation(s)
- P. Gladieux
- Ecologie; Systématique et Evolution; Université Paris-Sud; Bâtiment 360 F-91405 Orsay France
- CNRS; 91405 Orsay France
| | - A. Feurtey
- Ecologie; Systématique et Evolution; Université Paris-Sud; Bâtiment 360 F-91405 Orsay France
- CNRS; 91405 Orsay France
| | - M. E. Hood
- Department of Biology; Amherst College; Amherst Massachusetts 01002 USA
| | - A. Snirc
- Ecologie; Systématique et Evolution; Université Paris-Sud; Bâtiment 360 F-91405 Orsay France
- CNRS; 91405 Orsay France
| | - J. Clavel
- Conservation des Espèces; Restauration et Suivi des Populations - CRBPO; Muséum National d'Histoire Naturelle-CNRS-Université Pierre et Marie Curie; 55 rue Buffon 75005 Paris France
| | - C. Dutech
- Biodiversité Gènes et Communautés; INRA-Université Bordeaux 1; Site de Pierroton 33610 Cestas France
| | - M. Roy
- Evolution et Diversité Biologique; Université Toulouse Paul Sabatier-Ecole Nationale de Formation Agronomique-CNRS; 118 route de Narbonne 31062 Toulouse France
| | - T. Giraud
- Ecologie; Systématique et Evolution; Université Paris-Sud; Bâtiment 360 F-91405 Orsay France
- CNRS; 91405 Orsay France
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18
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Peters FS, Busskamp J, Prospero S, Rigling D, Metzler B. Genetic diversification of the chestnut blight fungus Cryphonectria parasitica and its associated hypovirus in Germany. Fungal Biol 2013; 118:193-210. [PMID: 24528641 DOI: 10.1016/j.funbio.2013.11.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 11/06/2013] [Accepted: 11/20/2013] [Indexed: 10/25/2022]
Abstract
Chestnut blight in south-western Germany was first reported in 1992 and is since expanding in distribution. Here we investigated the invasion history of Cryphonectria parasitica and its associated hypovirus. For this, we characterized 284 isolates collected between 1992 and 2012 for hypovirulence, vegetative compatibility (vc), mating type, and microsatellite haplotype. A total of 27 haplotypes and 15 vc types were observed, although the C. parasitica population analyzed is currently dominated to 50 % by one haplotype and to 64 % by the vc type EU-2. Structure analysis indicated two divergent genetic pools. Over 66 % of the haplotypes belonged to a pool probably originating from northern Italy. Further diversification is expected due to ongoing sexual recombination, but also to new migration and additional introductions. Cryphonectria hypovirus 1 (CHV-1) was found in four of five C. parasitica populations from Baden-Württemberg. Genetic analysis of the 35 CHV-1 isolates obtained revealed that they all belong to the German subtype, although they have clearly diverged from the first German hypovirus isolated in 1992. Our study suggests that C. parasitica has been introduced into Germany several times from two different gene pools, whereas the hypovirus most probably has a single origin.
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Affiliation(s)
- Franziska S Peters
- FVA Forest Research Institute of Baden-Württemberg (FVA-BW), Dept. Forest Protection, Wonnhaldestr. 4, D-79100 Freiburg, Germany.
| | - Johanna Busskamp
- FVA Forest Research Institute of Baden-Württemberg (FVA-BW), Dept. Forest Protection, Wonnhaldestr. 4, D-79100 Freiburg, Germany.
| | - Simone Prospero
- WSL Swiss Federal Research Institute, Zürcherstrasse 111, CH-8903 Birmensdorf, Switzerland.
| | - Daniel Rigling
- WSL Swiss Federal Research Institute, Zürcherstrasse 111, CH-8903 Birmensdorf, Switzerland.
| | - Berthold Metzler
- FVA Forest Research Institute of Baden-Württemberg (FVA-BW), Dept. Forest Protection, Wonnhaldestr. 4, D-79100 Freiburg, Germany.
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Prospero S, Lutz A, Tavadze B, Supatashvili A, Rigling D. Discovery of a new gene pool and a high genetic diversity of the chestnut blight fungus Cryphonectria parasitica in Caucasian Georgia. Infect Genet Evol 2013; 20:131-9. [PMID: 23994123 DOI: 10.1016/j.meegid.2013.08.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 08/08/2013] [Accepted: 08/12/2013] [Indexed: 11/24/2022]
Abstract
In this study, we investigated the population genetic structure and possible origins of the plant pathogen Cryphonectria parasitica in Caucasian Georgia, a region within the centre of origin of the host species Castanea sativa. A total of 427 C. parasitica isolates from nine populations were genotyped at 10 microsatellite loci. A high genetic diversity was detected, but the overall Georgian population was dominated by three haplotypes which were present in most individual populations. Two of them have not been previously found in Europe. Bayesian clustering analysis and principal component analysis could not identify their source population, neither in Asia nor in North America. On the other hand, one haplotype is frequent in Central Europe and probably naturally invaded Caucasian Georgia from neighbouring Turkey. Seventy-three haplotypes were unique to specific populations, and 66 of them were represented by a single isolate. Allele patterns suggest that most of these haplotypes emerged locally through sexual recombination between haplotypes of the Georgian and the central European gene pool. Due to the high incidence of haplotypes not otherwise present in Europe, Caucasian Georgia represents an additional source of diversity for the European C. parasitica population.
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Affiliation(s)
- S Prospero
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, CH-8903 Birmensdorf, Switzerland.
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Abstract
Cryphonectria hypovirus 1 hyperparasitizes the chestnut blight fungus Cryphonectria parasitica and acts as a biocontrol agent for this serious tree disease. The virus is transmitted cytoplasmatically between fungal individuals. However, highly virulent viruses strongly debilitate their host and, thus, reduce their own transmission probability. Furthermore, vegetative incompatibility between fungi is an important transmission barrier. Therefore, virulent viruses are expected to be strongly selected against in fungal populations with high levels of vegetative incompatibility, eventually leading to the erosion of biocontrol. To test this prediction, we assessed the virulence of the virus in four European C. parasitica populations with high diversity of vegetative compatibility types and in four populations with low diversity. We expected the degree of virus virulence to be lower in fungal populations with high levels of vegetative incompatibility. However, our results did not reveal such a trend. No significant differences in virus virulence between populations with low versus high diversity of vegetative compatibility types were observed. There was no evidence for an erosion of disease control due to the presence of these transmission barriers. Thus, the findings of this study are promising for the sustainability of Cryphonectria hypovirus 1 as a biocontrol agent for chestnut blight in Europe.
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Bryner SF, Rigling D, Brunner PC. Invasion history and demographic pattern of Cryphonectria hypovirus 1 across European populations of the chestnut blight fungus. Ecol Evol 2012; 2:3227-41. [PMID: 23301186 PMCID: PMC3539014 DOI: 10.1002/ece3.429] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Revised: 10/09/2012] [Accepted: 10/13/2012] [Indexed: 01/16/2023] Open
Abstract
We reconstructed the invasion history of the fungal virus Cryphonectria hypovirus 1 (CHV-1) in Europe, which infects the chestnut blight fungus Cryphonectria parasitica. The pattern of virus evolution was inferred based on nucleotide sequence variation from isolates sampled across a wide area in Europe at different points in time. Phylogeny and time estimates suggested that CHV-1 was introduced together with its fungal host to Europe and that it rapidly colonized the central range along the south facing slopes of the Alps and the north-east facing slopes of the Dinaric Alps. These central populations were the source for two waves of simultaneous invasions toward the southern Balkans and Turkey, as indicated by migration rates. Our results showed that the evolutionary scenarios for CHV-1 and C. parasitica were spatially congruent. As infection with CHV-1 reduces the pathogenicity of C. parasitica toward the chestnut tree, CHV-1 invasions of the newly established C. parasitica populations probably prevented the development of devastating chestnut blight epidemics in Europe. We propose that in this, and supposedly in other pathosystems, geographic, vegetation-related, demographic, economic, and political factors may help explain the correlated invasion pattern of a parasite and its host.
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Affiliation(s)
- Sarah F Bryner
- WSL Swiss Federal Research Institute CH-8903, Birmensdorf, Switzerland
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