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Clavé C, Dheur S, Ament-Velásquez SL, Granger-Farbos A, Saupe SJ. het-B allorecognition in Podospora anserina is determined by pseudo-allelic interaction of genes encoding a HET and lectin fold domain protein and a PII-like protein. PLoS Genet 2024; 20:e1011114. [PMID: 38346076 PMCID: PMC10890737 DOI: 10.1371/journal.pgen.1011114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 02/23/2024] [Accepted: 01/29/2024] [Indexed: 02/25/2024] Open
Abstract
Filamentous fungi display allorecognition genes that trigger regulated cell death (RCD) when strains of unlike genotype fuse. Podospora anserina is one of several model species for the study of this allorecognition process termed heterokaryon or vegetative incompatibility. Incompatibility restricts transmission of mycoviruses between isolates. In P. anserina, genetic analyses have identified nine incompatibility loci, termed het loci. Here we set out to clone the genes controlling het-B incompatibility. het-B displays two incompatible alleles, het-B1 and het-B2. We find that the het-B locus encompasses two adjacent genes, Bh and Bp that exist as highly divergent allelic variants (Bh1/Bh2 and Bp1/Bp2) in the incompatible haplotypes. Bh encodes a protein with an N-terminal HET domain, a cell death inducing domain bearing homology to Toll/interleukin-1 receptor (TIR) domains and a C-terminal domain with a predicted lectin fold. The Bp product is homologous to PII-like proteins, a family of small trimeric proteins acting as sensors of adenine nucleotides in bacteria. We show that although the het-B system appears genetically allelic, incompatibility is in fact determined by the non-allelic Bh1/Bp2 interaction while the reciprocal Bh2/Bp1 interaction plays no role in incompatibility. The highly divergent C-terminal lectin fold domain of BH determines recognition specificity. Population studies and genome analyses indicate that het-B is under balancing selection with trans-species polymorphism, highlighting the evolutionary significance of the two incompatible haplotypes. In addition to emphasizing anew the central role of TIR-like HET domains in fungal RCD, this study identifies novel players in fungal allorecognition and completes the characterization of the entire het gene set in that species.
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Affiliation(s)
- Corinne Clavé
- IBGC, UMR 5095, CNRS-Université de Bordeaux, Bordeaux, France
| | - Sonia Dheur
- IBGC, UMR 5095, CNRS-Université de Bordeaux, Bordeaux, France
| | | | | | - Sven J. Saupe
- IBGC, UMR 5095, CNRS-Université de Bordeaux, Bordeaux, France
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2
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Romon-Ochoa P, Samal P, Gorton C, Lewis A, Chitty R, Eacock A, Krzywinska E, Crampton M, Pérez-Sierra A, Biddle M, Jones B, Ward L. Cryphonectria parasitica Detections in England, Jersey, and Guernsey during 2020-2023 Reveal Newly Affected Areas and Infections by the CHV1 Mycovirus. J Fungi (Basel) 2023; 9:1036. [PMID: 37888292 PMCID: PMC10607933 DOI: 10.3390/jof9101036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 10/08/2023] [Accepted: 10/09/2023] [Indexed: 10/28/2023] Open
Abstract
In England, Cryphonectria parasitica was detected for the first time in 2011 in a nursery and in 2016 in the wider environment. Surveys between 2017 and 2020 identified the disease at different sites in Berkshire, Buckinghamshire, Cornwall, Derbyshire, Devon, Dorset, London, West Sussex, and the island of Jersey, while the present study comprises the results of the 2020-2023 survey with findings in Derbyshire, Devon, Kent, Nottinghamshire, Herefordshire, Leicestershire, London, West Sussex, and the islands of Jersey and Guernsey. A total of 226 suspected samples were collected from 72 surveyed sites, as far north as Edinburgh and as far west as Plymouth (both of which were negative), and 112 samples tested positive by real-time PCR and isolation from 35 sites. The 112 isolates were tested for the vegetative compatibility group (VCG), mating type, and Cryphonectria hypovirus 1 (CHV1). Twelve VCGs were identified, with two of them (EU-5 and EU-22) being the first records in the UK. Both mating types were present (37% MAT-1 and 63% MAT-2), but only one mating type was present per site and VCG, and perithecia were never observed. Cryphonectria hypovirus 1 (CHV1), consistently subtype-I haplotype E-5, was detected in three isolates at a low concentration (5.9, 21.1, and 33.0 ng/µL) from locations in London, Nottinghamshire, and Devon.
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Affiliation(s)
- Pedro Romon-Ochoa
- Forest Research, Plant Pathology Department, Alice Holt Research Station, Farnham, Surrey GU10 4LH, UK; (P.S.); (M.B.); (L.W.)
| | - Pankajini Samal
- Forest Research, Plant Pathology Department, Alice Holt Research Station, Farnham, Surrey GU10 4LH, UK; (P.S.); (M.B.); (L.W.)
| | - Caroline Gorton
- Forest Research, THDAS-Tree Health Diagnostics and Advisory Service, Alice Holt Research Station, Farnham, Surrey GU10 4LH, UK; (C.G.); (A.L.); (R.C.); (A.E.); (E.K.); (M.C.); (A.P.-S.)
| | - Alex Lewis
- Forest Research, THDAS-Tree Health Diagnostics and Advisory Service, Alice Holt Research Station, Farnham, Surrey GU10 4LH, UK; (C.G.); (A.L.); (R.C.); (A.E.); (E.K.); (M.C.); (A.P.-S.)
| | - Ruth Chitty
- Forest Research, THDAS-Tree Health Diagnostics and Advisory Service, Alice Holt Research Station, Farnham, Surrey GU10 4LH, UK; (C.G.); (A.L.); (R.C.); (A.E.); (E.K.); (M.C.); (A.P.-S.)
| | - Amy Eacock
- Forest Research, THDAS-Tree Health Diagnostics and Advisory Service, Alice Holt Research Station, Farnham, Surrey GU10 4LH, UK; (C.G.); (A.L.); (R.C.); (A.E.); (E.K.); (M.C.); (A.P.-S.)
| | - Elzbieta Krzywinska
- Forest Research, THDAS-Tree Health Diagnostics and Advisory Service, Alice Holt Research Station, Farnham, Surrey GU10 4LH, UK; (C.G.); (A.L.); (R.C.); (A.E.); (E.K.); (M.C.); (A.P.-S.)
| | - Michael Crampton
- Forest Research, THDAS-Tree Health Diagnostics and Advisory Service, Alice Holt Research Station, Farnham, Surrey GU10 4LH, UK; (C.G.); (A.L.); (R.C.); (A.E.); (E.K.); (M.C.); (A.P.-S.)
| | - Ana Pérez-Sierra
- Forest Research, THDAS-Tree Health Diagnostics and Advisory Service, Alice Holt Research Station, Farnham, Surrey GU10 4LH, UK; (C.G.); (A.L.); (R.C.); (A.E.); (E.K.); (M.C.); (A.P.-S.)
| | - Mick Biddle
- Forest Research, Plant Pathology Department, Alice Holt Research Station, Farnham, Surrey GU10 4LH, UK; (P.S.); (M.B.); (L.W.)
| | - Ben Jones
- Forestry Commission, 620 Bristol Business Park, Bristol BS16 1EJ, UK;
| | - Lisa Ward
- Forest Research, Plant Pathology Department, Alice Holt Research Station, Farnham, Surrey GU10 4LH, UK; (P.S.); (M.B.); (L.W.)
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3
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Blumenstein K, Bußkamp J, Langer GJ, Terhonen E. Diplodia tip blight pathogen's virulence empowered through host switch. FRONTIERS IN FUNGAL BIOLOGY 2022; 3:939007. [PMID: 37746207 PMCID: PMC10512300 DOI: 10.3389/ffunb.2022.939007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Accepted: 07/04/2022] [Indexed: 09/26/2023]
Abstract
Increased drought combined with emerging pathogens poses an increased threat to forest health. This is attributable to the unpredictable behaviour of forest pathosystems, which can favour fungal pathogens over the host under persistent drought stress conditions. Diplodia sapinea (≡ Sphaeropsis sapinea) is one of the most severe pathogens in Scots pine (Pinus sylvestris) causing Diplodia tip blight (conifer blight) under certain environmental conditions. Recently, the fungus has also been isolated from non-conifer hosts, indicating that it has a broader host range than previously known. In this study we compared the impact of different levels of water availability on necrosis length caused by D. sapinea strains isolated as endophytes (eight strains isolated from asymptomatic Scots pine) and pathogens (five strains isolated from symptomatic Scots pine) and five strains isolated from symptomatic non-pine hosts. For all strains the decreased water availability increased the necrosis length in Scots pine shoots. The isolates from non-pine hosts caused the most severe reactions under all water availabilities. The results of the study indicate the likelihood that effects of climatic changes such as drought will drive D. sapinea damage in Scots pine-dominated forests and increase mortality rates in affected trees. Further, the higher necrosis in the Scots pines caused by strains that had performed a host switch are concerning with regard to future scenarios thus increasing infection pressure on Scots pine from unknown sources.
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Affiliation(s)
- Kathrin Blumenstein
- Forest Pathology Research Group, Department of Forest Botany and Tree Physiology, Faculty of Forest Sciences and Forest Ecology, Georg-August-University Göttingen, Göttingen, Germany
- Chair of Pathology of Trees, Institute of Forestry, Faculty of Environment and Natural Resources, University of Freiburg, Freiburg, Germany
| | - Johanna Bußkamp
- Section Mycology and Complex Diseases, Department of Forest Protection, Northwest German Forest Research Institute, Göttingen, Germany
| | - Gitta Jutta Langer
- Section Mycology and Complex Diseases, Department of Forest Protection, Northwest German Forest Research Institute, Göttingen, Germany
| | - Eeva Terhonen
- Forest Pathology Research Group, Department of Forest Botany and Tree Physiology, Faculty of Forest Sciences and Forest Ecology, Georg-August-University Göttingen, Göttingen, Germany
- Natural Resources Institute Finland (Luke), Forest Health and Biodiversity, Helsinki, Finland
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4
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Nuskern L, Stojanović M, Milanović-Litre M, Šibenik T, Ježić M, Poljak I, Ćurković-Perica M. Filling the Gap in Southern Europe—Diversity of Cryphonectria parasitica and Associated Mycovirus (Cryphonectria hypovirus 1) in Montenegro. J Fungi (Basel) 2022; 8:jof8060552. [PMID: 35736034 PMCID: PMC9224863 DOI: 10.3390/jof8060552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/19/2022] [Accepted: 05/20/2022] [Indexed: 11/16/2022] Open
Abstract
Cryphonectria parasitica is an invasive fungal pathogen that causes blight disease on chestnut trees. Its destructive effect can be controlled with naturally occurring mycovirus Cryphonectria hypovirus 1 (CHV1). To date, the spread of C. parasitica and CHV1 in Europe is fairly well documented, but there are still several unexplored regions. Thus, we sampled blight cankers from four sweet chestnut populations in Bay of Kotor and Lake Skadar regions in Montenegro. We determined vegetative compatibility (vc) type and mating-type diversity using molecular vic and MAT1 genotyping, as well as confirming the presence of CHV1 by RT-PCR. We identified 11 vc types, with EU-12 being the dominant one represented by 58.2% of all fungal isolates. The Shannon diversity index ranged from 0.93 to 1.47. Both mating types of C. parasitica were found in all four populations. The prevalence of CHV1 ranged from 15% to 40%. All CHV1 isolates belonged to Italian subtype I of CHV1 and were closely related, with relatively recent common ancestors. Our results indicate a longer presence of C. parasitica and CHV1 in Montenegro than previously thought. Natural biocontrol with CHV1 seems to be well established. However, it has the potential for deterioration; thus, close monitoring is required.
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Affiliation(s)
- Lucija Nuskern
- Division of Microbiology, Department of Biology, Faculty of Science, University of Zagreb, Marulićev trg 9a, 10000 Zagreb, Croatia; (L.N.); (M.M.-L.); (T.Š.); (M.J.)
| | - Milena Stojanović
- Biotechnical Faculty, University of Montenegro, Mihaila Lalića Br. 15, 81000 Podgorica, Montenegro;
| | - Marija Milanović-Litre
- Division of Microbiology, Department of Biology, Faculty of Science, University of Zagreb, Marulićev trg 9a, 10000 Zagreb, Croatia; (L.N.); (M.M.-L.); (T.Š.); (M.J.)
| | - Tena Šibenik
- Division of Microbiology, Department of Biology, Faculty of Science, University of Zagreb, Marulićev trg 9a, 10000 Zagreb, Croatia; (L.N.); (M.M.-L.); (T.Š.); (M.J.)
| | - Marin Ježić
- Division of Microbiology, Department of Biology, Faculty of Science, University of Zagreb, Marulićev trg 9a, 10000 Zagreb, Croatia; (L.N.); (M.M.-L.); (T.Š.); (M.J.)
| | - Igor Poljak
- Department of Forest Genetics, Dendrology and Botany, Faculty of Forestry and Wood Technology, University of Zagreb, Svetošimunska Cesta 23, 10000 Zagreb, Croatia;
| | - Mirna Ćurković-Perica
- Division of Microbiology, Department of Biology, Faculty of Science, University of Zagreb, Marulićev trg 9a, 10000 Zagreb, Croatia; (L.N.); (M.M.-L.); (T.Š.); (M.J.)
- Correspondence: ; Tel.: +385-(0)1-4898-076
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5
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Stauber L, Croll D, Prospero S. Temporal changes in pathogen diversity in a perennial plant-pathogen-hyperparasite system. Mol Ecol 2022; 31:2073-2088. [PMID: 35122694 PMCID: PMC9540319 DOI: 10.1111/mec.16386] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 01/26/2022] [Accepted: 01/31/2022] [Indexed: 11/27/2022]
Abstract
Hyperparasites can affect the evolution of pathosystems by influencing the stability of both pathogen and host populations. However, how pathogens of perennial hosts evolve in the presence of a hyperparasite has rarely been studied. Here, we investigated temporal changes in genetic diversity of the invasive chestnut blight pathogen Cryphonectria parasitica in the presence of its parasitic mycovirus Cryphonectria hypovirus 1 (CHV1). The virus reduces fungal virulence and represents an effective natural biocontrol agent against chestnut blight in Europe. We analysed genome-wide diversity and CHV1 prevalence in C. parasitica populations in southern Switzerland that were sampled twice at an interval of about 30 years. Overall, we found that both pathogen population structure and CHV1 prevalence were retained over time. The results suggest that recent bottlenecks have influenced the structure of C. parasitica populations in southern Switzerland. Strong balancing selection signals were found at a single vegetative incompatibility (vic) locus, consistent with negative frequency-dependent selection imposed by the vegetative incompatibility system. High levels of mating among related individuals (i.e., inbreeding) and genetic drift are probably at the origin of imbalanced allele ratios at vic loci and subsequently low vc type diversity. Virus infection rates were stable at ~30% over the study period and we found no significant impact of the virus on fungal population diversity. Consequently, the efficacy of CHV1-mediated biocontrol was probably retained.
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Affiliation(s)
- Lea Stauber
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL)BirmensdorfSwitzerland
- Laboratory of Evolutionary GeneticsInstitute of BiologyUniversity of NeuchâtelNeuchâtelSwitzerland
- Department of Environmental SciencesUniversity of BaselBaselSwitzerland
| | - Daniel Croll
- Laboratory of Evolutionary GeneticsInstitute of BiologyUniversity of NeuchâtelNeuchâtelSwitzerland
| | - Simone Prospero
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL)BirmensdorfSwitzerland
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6
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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] [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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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] [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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In-Tree Behavior of Diverse Viruses Harbored in the Chestnut Blight Fungus, Cryphonectria parasitica. J Virol 2021; 95:JVI.01962-20. [PMID: 33361433 DOI: 10.1128/jvi.01962-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 12/17/2020] [Indexed: 12/20/2022] Open
Abstract
The ascomycete Cryphonectria parasitica causes destructive chestnut blight. Biological control of the fungus by virus infection (hypovirulence) has been shown to be an effective control strategy against chestnut blight in Europe. To provide biocontrol effects, viruses must be able to induce hypovirulence and spread efficiently in chestnut trees. Field studies using living trees to date have focused on a selected family of viruses called hypoviruses, especially prototypic hypovirus CHV1, but there are now known to be many other viruses that infect C. parasitica Here, we tested seven different viruses for their hypovirulence induction, biocontrol potential, and transmission properties between two vegetatively compatible but molecularly distinguishable fungal strains in trees. The test included cytosolically and mitochondrially replicating viruses with positive-sense single-stranded RNA or double-stranded RNA genomes. The seven viruses showed different in planta behaviors and were classified into four groups. Group I, including CHV1, had great biocontrol potential and could protect trees by efficiently spreading and converting virulent to hypovirulent cankers in the trees. Group II could induce high levels of hypovirulence but showed much smaller biocontrol potential, likely because of inefficient virus transmission. Group III showed poor performance in hypovirulence induction and biocontrol, while efficiently being transmitted in the infected trees. Group IV could induce hypovirulence and spread efficiently but showed poor biocontrol potential. Nuclear and mitochondrial genotyping of fungal isolates obtained from the treated cankers confirmed virus transmission between the two fungal strains in most isolates. These results are discussed in view of dynamic interactions in the tripartite pathosystem.IMPORTANCE The ascomycete Cryphonectria parasitica causes destructive chestnut blight, which is controllable by hypovirulence-conferring viruses infecting the fungus. The tripartite chestnut/C. parasitica/virus pathosystem involves the dynamic interactions of their genetic elements, i.e., virus transmission and lateral transfer of nuclear and mitochondrial genomes between fungal strains via anastomosis occurring in trees. Here, we tested diverse RNA viruses for their hypovirulence induction, biocontrol potential, and transmission properties between two vegetatively compatible but molecularly distinguishable fungal strains in live chestnut trees. The tested viruses, which are different in genome type (single-stranded or double-stranded RNA) and organization, replication site (cytosol or mitochondria), virus form (encapsidated or capsidless) and/or symptomatology, have been unexplored in the aforementioned aspects under controlled conditions. This study showed intriguing different in-tree behaviors of the seven viruses and suggested that to exert significant biocontrol effects, viruses must be able to induce hypovirulence and spread efficiently in the fungus infecting the chestnut trees.
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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] [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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10
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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] [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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Milgroom MG, Smith ML, Drott MT, Nuss DL. Balancing selection at nonself recognition loci in the chestnut blight fungus, Cryphonectria parasitica, demonstrated by trans-species polymorphisms, positive selection, and even allele frequencies. Heredity (Edinb) 2018; 121:511-523. [PMID: 29426879 DOI: 10.1038/s41437-018-0060-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 01/12/2018] [Accepted: 01/15/2018] [Indexed: 11/09/2022] Open
Abstract
Balancing selection has been inferred in diverse organisms for nonself recognition genes, including those involved in immunity, mating compatibility, and vegetative incompatibility. Although selective forces maintaining polymorphisms are known for genes involved in immunity and mating, mechanisms of balancing selection for vegetative incompatibility genes in fungi are being debated. We hypothesized that allorecognition and its consequent inhibition of virus transmission contribute to the maintenance of polymorphisms in vegetative incompatibility loci (vic) in the chestnut blight fungus, Cryphonectria parasitica. Balancing selection was demonstrated at two loci, vic2 and vic6, by trans-species polymorphisms in C. parasitica, C. radicalis, and C. japonica and signatures of positive selection in gene sequences. In addition, more than half (31 of 54) of allele frequency estimates at six vic loci in nine field populations of C. parasitica from Asia and the eastern US were not significantly different from 0.5, as expected at equilibrium for two alleles per locus under balancing selection. At three vic loci, deviations from 0.5 were predicted based on the effects of heteroallelism on virus transmission. Twenty-five of 27 allele frequency estimates were greater than or equal to 0.5 for the allele that confers significantly stronger inhibition of virus transmission at three loci with asymmetric transmission. These results are consistent with the allorecognition hypothesis that vegetative incompatibility genes are under selection because of their role in reducing infection by viruses.
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Affiliation(s)
- Michael G Milgroom
- School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology Section, Cornell University, Ithaca, NY, 14853, USA.
| | - Myron L Smith
- Department of Biology, Carleton University, Ottawa, ON, K1S 5B6, Canada
| | - Milton T Drott
- School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology Section, Cornell University, Ithaca, NY, 14853, USA
| | - Donald L Nuss
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, 20850, USA.,Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, 26506, USA
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12
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Rigling D, Prospero S. Cryphonectria parasitica, the causal agent of chestnut blight: invasion history, population biology and disease control. MOLECULAR PLANT PATHOLOGY 2018; 19:7-20. [PMID: 28142223 PMCID: PMC6638123 DOI: 10.1111/mpp.12542] [Citation(s) in RCA: 189] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 12/19/2016] [Accepted: 01/26/2017] [Indexed: 05/25/2023]
Abstract
Chestnut blight, caused by Cryphonectria parasitica, is a devastating disease infecting American and European chestnut trees. The pathogen is native to East Asia and was spread to other continents via infected chestnut plants. This review summarizes the current state of research on this pathogen with a special emphasis on its interaction with a hyperparasitic mycovirus that acts as a biological control agent of chestnut blight. TAXONOMY Cryphonectria parasitica (Murr.) Barr. is a Sordariomycete (ascomycete) fungus in the family Cryphonectriaceae (Order Diaporthales). Closely related species that can also be found on chestnut include Cryphonectria radicalis, Cryphonectria naterciae and Cryphonectria japonica. HOST RANGE Major hosts are species in the genus Castanea (Family Fagaceae), particularly the American chestnut (C. dentata), the European chestnut (C. sativa), the Chinese chestnut (C. mollissima) and the Japanese chestnut (C. crenata). Minor incidental hosts include oaks (Quercus spp.), maples (Acer spp.), European hornbeam (Carpinus betulus) and American chinkapin (Castanea pumila). DISEASE SYMPTOMS Cryphonectria parasitica causes perennial necrotic lesions (so-called cankers) on the bark of stems and branches of susceptible host trees, eventually leading to wilting of the plant part distal to the infection. Chestnut blight cankers are characterized by the presence of mycelial fans and fruiting bodies of the pathogen. Below the canker the tree may react by producing epicormic shoots. Non-lethal, superficial or callusing cankers on susceptible host trees are usually associated with mycovirus-induced hypovirulence. DISEASE CONTROL After the introduction of C. parasitica into a new area, eradication efforts by cutting and burning the infected plants/trees have mostly failed. In Europe, the mycovirus Cryphonectria hypovirus 1 (CHV-1) acts as a successful biological control agent of chestnut blight by causing so-called hypovirulence. CHV-1 infects C. parasitica and reduces its parasitic growth and sporulation capacity. Individual cankers can be therapeutically treated with hypovirus-infected C. parasitica strains. The hypovirus may subsequently spread to untreated cankers and become established in the C. parasitica population. Hypovirulence is present in many chestnut-growing regions of Europe, either resulting naturally or after biological control treatments. In North America, disease management of chestnut blight is mainly focused on breeding with the goal to backcross the Chinese chestnut's blight resistance into the American chestnut genome.
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Affiliation(s)
- Daniel Rigling
- Swiss Federal Institute for ForestSnow and Landscape Research (WSL)Birmensdorf8903Switzerland
| | - Simone Prospero
- Swiss Federal Institute for ForestSnow and Landscape Research (WSL)Birmensdorf8903Switzerland
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13
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Liu YC, Milgroom MG. High diversity of vegetative compatibility types inCryphonectria parasiticain Japan and China. Mycologia 2017. [DOI: 10.1080/15572536.2007.11832587] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
| | - Michael G. Milgroom
- Department of Plant Pathology, Cornell University, Ithaca, New York 14853-4203
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14
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Vegetative incompatibility in fungi: From recognition to cell death, whatever does the trick. FUNGAL BIOL REV 2016. [DOI: 10.1016/j.fbr.2016.08.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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15
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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] [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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Jiménez-Gasco MDM, Malcolm GM, Berbegal M, Armengol J, Jiménez-Díaz RM. Complex molecular relationship between vegetative compatibility groups (VCGs) in Verticillium dahliae: VCGs do not always align with clonal lineages. PHYTOPATHOLOGY 2014; 104:650-659. [PMID: 24328492 DOI: 10.1094/phyto-07-13-0180-r] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Verticillium wilts caused by the soilborne fungus Verticillium dahliae are among the most challenging diseases to control. Populations of this pathogen have been traditionally studied by means of vegetative compatibility groups (VCGs) under the assumption that VCGs comprise genetically related isolates that correlate with clonal lineages. We aimed to resolve the phylogenetic relationships among VCGs and their subgroups based on sequences of the intergenic spacer region (IGS) of the ribosomal DNA and six anonymous polymorphic sequences containing single-nucleotide polymorphisms (VdSNPs). A collection of 68 V. dahliae isolates representing the main VCGs and subgroups (VCGs 1A, 1B, 2A, 2B, 3, 4A, 4B, and 6) from different geographic origins and hosts was analyzed using the seven DNA regions. Maximum parsimony (MP) phylogenies inferred from IGS and VdSNP sequences showed five and six distinct clades, respectively. Phylogenetic analyses of individual and combined data sets indicated that certain VCG subgroups (e.g., VCGs 1A and 1B) are closely related and share a common ancestor; however, other subgroups (e.g., VCG 4B) are more closely related to members of a different VCG (e.g., VCG 2A) than to subgroups of the same VCG (VCG 4B). Furthermore, MP analyses indicated that VCG 2B is polyphyletic, with isolates placed in at least three distinct phylogenetic lineages based on IGS sequences and two lineages based on VdSNP sequences. Results from our study suggest the existence of main VCG lineages that contain VCGs 1A and 1B; VCGs 2A and 4B; and VCG 4A, for which both phylogenies agree; and the existence of other VCGs or VCG subgroups that seem to be genetically heterogeneous or show discrepancies in their phylogenetic placement: VCG 2B, VCG 3, and VCG 6. These results raise important caveats regarding the interpretation of VCG analyses: genetic homogeneity and close evolutionary relationship between members of a VCG should not be assumed.
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Chagnon PL. Ecological and evolutionary implications of hyphal anastomosis in arbuscular mycorrhizal fungi. FEMS Microbiol Ecol 2014; 88:437-44. [DOI: 10.1111/1574-6941.12321] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 03/05/2014] [Accepted: 03/06/2014] [Indexed: 01/10/2023] Open
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Vegetative incompatibility loci with dedicated roles in allorecognition restrict mycovirus transmission in chestnut blight fungus. Genetics 2014; 197:701-14. [PMID: 24690544 DOI: 10.1534/genetics.114.164574] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Vegetative incompatibility (vic), a form of nonself allorecognition, operates widely in filamentous fungi and restricts transmission of virulence-attenuating hypoviruses in the chestnut blight fungus Cryphonectria parasitica. We report here the use of a polymorphism-based comparative genomics approach to complete the molecular identification of the genetically defined C. parasitica vic loci with the identification of vic1 and vic3. The vic1 locus in the C. parasitica reference strain EP155 consists of a polymorphic HET-domain-containing 771-aa ORF designated vic1a-2, which shares 91% identity with the corresponding vic1a-1 allele, and a small (172 aa) idiomorphic DUF1909-domain-containing ORF designated vic1b-2 that is absent at the vic1-1 locus. Gene disruption of either vic1a-2 or vic1b-2 in strain EP155 eliminated restrictions on virus transmission when paired with a vic1 heteroallelic strain; however, only disruption of vic1a-2 abolished the incompatible programmed cell death (PCD) reaction. The vic3 locus of strain EP155 contains two polymorphic ORFs of 599 aa (vic3a-1) and 102 aa (vic3b-1) that shared 46 and 85% aa identity with the corresponding vic3a-2 and vic3b-2 alleles, respectively. Disruption of either vic3a-1 or vic3b-1 resulted in increased virus transmission. However, elimination of PCD required disruption of both vic3a and vic3b. Additional allelic heterogeneity included a sequence inversion and a 8.5-kb insertion containing a LTR retrotransposon sequence and an adjacent HET-domain gene at the vic1 locus and a 7.7-kb sequence deletion associated with a nonfunctional, pseudo vic locus. Combined gene disruption studies formally confirmed restriction of mycovirus transmission by five C. parasitica vic loci and suggested dedicated roles in allorecognition. The relevance of these results to the acquisition and maintenance of vic genes and the potential for manipulation of vic alleles for enhanced mycovirus transmission are discussed.
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Van der Nest MA, Olson A, Lind M, Vélëz H, Dalman K, Brandström Durling M, Karlsson M, Stenlid J. Distribution and evolution of het gene homologs in the basidiomycota. Fungal Genet Biol 2013; 64:45-57. [PMID: 24380733 DOI: 10.1016/j.fgb.2013.12.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 12/04/2013] [Accepted: 12/20/2013] [Indexed: 12/24/2022]
Abstract
In filamentous fungi a system known as somatic incompatibility (SI) governs self/non-self recognition. SI is controlled by a regulatory signaling network involving proteins encoded at the het (heterokaryon incompatible) loci. Despite the wide occurrence of SI, the molecular identity and structure of only a small number of het genes and their products have been characterized in the model fungi Neurospora crassa and Podospora anserina. Our aim was to identify and study the distribution and evolution of putative het gene homologs in the Basidiomycota. For this purpose we used the information available for the model fungi to identify homologs of het genes in other fungi, especially the Basidiomycota. Putative het-c, het-c2 and un-24 homologs, as well as sequences containing the NACHT, HET or WD40 domains present in the het-e, het-r, het-6 and het-d genes were identified in certain members of the Ascomycota and Basidiomycota. The widespread phylogenetic distribution of certain het genes may reflect the fact that the encoded proteins are involved in fundamental cellular processes other than SI. Although homologs of het-S were previously known only from the Sordariomycetes (Ascomycota), we also identified a putative homolog of this gene in Gymnopus luxurians (Basidiomycota, class Agaricomycetes). Furthermore, with the exception of un-24, all of the putative het genes identified occurred mostly in a multi-copy fashion, some with lineage and species-specific expansions. Overall our results indicated that gene duplication followed by gene loss and/or gene family expansion, as well as multiple events of domain fusion and shuffling played an important role in the evolution of het gene homologs of Basidiomycota and other filamentous fungi.
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Affiliation(s)
- M A Van der Nest
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala SE-750 07, Sweden.
| | - A Olson
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala SE-750 07, Sweden
| | - M Lind
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala SE-750 07, Sweden
| | - H Vélëz
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala SE-750 07, Sweden
| | - K Dalman
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala SE-750 07, Sweden
| | - M Brandström Durling
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala SE-750 07, Sweden
| | - M Karlsson
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala SE-750 07, Sweden
| | - J Stenlid
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala SE-750 07, Sweden
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20
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Springer JC, Davelos Baines AL, Fulbright DW, Chansler MT, Jarosz AM. Hyperparasites influence population structure of the chestnut blight pathogen, Cryphonectria parasitica. PHYTOPATHOLOGY 2013; 103:1280-1286. [PMID: 23819549 DOI: 10.1094/phyto-10-12-0273-r] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Vegetative compatibility (VC) is commonly used to characterize structure and diversity in fungal populations. In the chestnut blight fungus, Cryphonectria parasitica, high VC diversity is hypothesized to be responsible for the failure of hyperparasitic mycoviruses to spread through pathogen populations in North America. To test this hypothesis, we assessed VC diversity at three recovering sites in Michigan where mycoviruses had invaded and compared them with four epidemic population sites where mycoviruses were absent. VC diversity was assessed for samples collected in 1996 and 2009, which allowed us to determine how C. parasitica populations changed with time. Twelve VC types were found in 1996 while 29 were found in 2009; 75% of types overlapped between the sample dates. Sites where mycoviruses were present had unique VC structures with the exception of the recovering population site at County Line where the main VC group was also detected at two epidemic sites. With one exception, epidemic sites contained more VC groups and displayed higher population level diversity than recovering sites. Mating-type analyses of blight populations revealed that two of three recovering populations were significantly skewed for MAT2 suggesting asexual reproduction, while epidemic sites with a long history of blight infection had ratios near 50:50 suggesting sexual reproduction. We propose that selection in the largely asexual C. parasitica populations at two recovering sites favors the most-fit fungal genotype by mycovirus combination and results in reduced diversity relative to the sexually reproducing pathogen populations at epidemic sites.
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21
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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] [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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22
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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. INFECTION GENETICS AND EVOLUTION 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] [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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23
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Abstract
Exotic, invasive pathogens have emerged repeatedly and continue to emerge to threaten the world's forests. Ecosystem structure and function can be permanently changed when keystone tree species such as the American chestnut (Castanea dentata) are eliminated from a whole range by disease. The fungal ascomycete pathogen Cryphonectria parasitica is responsible for causing chestnut blight. Once the pathogen was introduced into the Eastern US, where chestnuts were predominant, chestnuts were all but eliminated. This pathogen is currently causing extensive damage in Europe. A study in this issue of Molecular Ecology sheds new light on the pattern and process of emergence of this devastating plant pathogen (Dutech et al. 2012). The authors used microsatellite markers to investigate the evolutionary history of C. parasitica populations introduced into North America and Europe. To infer sources of migrants and the migration events, the authors included putative source populations endemic to China and Japan, inferred potentially unsampled populations and conducted a multivariate population genetic and complex ABC analysis. Cryphonectria parasitica emerges as an example of an introduced pathogen with limited genotypic diversity and some admixture in the invaded ranges, yet repeated invasions into different areas of Europe and the United States. This work sheds new light on the emergence of C. parasitica providing compelling evidence that this pathogen emerged by repeated migration and occasional admixture.
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Affiliation(s)
- Niklaus J Grünwald
- Horticultural Crops Research Laboratory, USDA Agricultural Research Service (ARS), Corvallis, OR 97330, USA.
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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: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [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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25
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Nydam ML, Taylor AA, De Tomaso AW. Evidence for selection on a chordate histocompatibility locus. Evolution 2012; 67:487-500. [PMID: 23356620 DOI: 10.1111/j.1558-5646.2012.01787.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Allorecognition is the ability of an organism to differentiate self or close relatives from unrelated individuals. The best known applications of allorecognition are the prevention of inbreeding in hermaphroditic species (e.g., the self-incompatibility [SI] systems in plants), the vertebrate immune response to foreign antigens mediated by MHC loci, and somatic fusion, where two genetically independent individuals physically join to become a chimera. In the few model systems where the loci governing allorecognition outcomes have been identified, the corresponding proteins have exhibited exceptional polymorphism. But information about the evolution of this polymorphism outside MHC is limited. We address this subject in the ascidian Botryllus schlosseri, where allorecognition outcomes are determined by a single locus, called FuHC (Fusion/HistoCompatibility). Molecular variation in FuHC is distributed almost entirely within populations, with very little evidence for differentiation among different populations. Mutation plays a larger role than recombination in the creation of FuHC polymorphism. A selection statistic, neutrality tests, and distribution of variation within and among different populations all provide evidence for selection acting on FuHC, but are not in agreement as to whether the selection is balancing or directional.
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Affiliation(s)
- Marie L Nydam
- Division of Science and Mathematics, Centre College, Danville, Kentucky 40422, USA.
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Dutech C, Barrès B, Bridier J, Robin C, Milgroom MG, Ravigné V. The chestnut blight fungus world tour: successive introduction events from diverse origins in an invasive plant fungal pathogen. Mol Ecol 2012; 21:3931-46. [PMID: 22548317 DOI: 10.1111/j.1365-294x.2012.05575.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Clonal expansion has been observed in several invasive fungal plant pathogens colonizing new areas, raising the question of the origin of clonal lineages. Using microsatellite markers, we retraced the evolutionary history of introduction of the chestnut blight fungus, Cryphonectria parasitica, in North America and western Europe. Combining discriminant analysis of principal components and approximate Bayesian computation analysis, we showed that several introduction events from genetically differentiated source populations have occurred in both invaded areas. In addition, a low signal of genetic recombination among different source populations was suggested in North America. Finally, two genetic lineages were present in both invaded areas as well as in the native areas, suggesting the existence of genetic lineages with a high capacity to establish in diverse environments and host species. This study confirmed the importance of multiple introductions, but questioned the role of genetic admixture in the success of introduction of a fungal plant pathogen.
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Affiliation(s)
- C Dutech
- INRA, UMR1202 BIOGECO, Cestas F-33610, France.
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27
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Diverse sources of infection and cryptic recombination revealed in South African Diplodia pinea populations. Fungal Biol 2012; 116:112-20. [DOI: 10.1016/j.funbio.2011.10.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2010] [Revised: 10/03/2011] [Accepted: 10/23/2011] [Indexed: 11/23/2022]
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Prospero S, Rigling D. Invasion genetics of the chestnut blight fungus Cryphonectria parasitica in Switzerland. PHYTOPATHOLOGY 2012; 102:73-82. [PMID: 21848397 DOI: 10.1094/phyto-02-11-0055] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Cryphonectria parasitica is the best-known example of an invasive forest pathogen in Europe. In southern Switzerland, chestnut blight was first reported in 1948 whereas, north of the Alps, it did not appear until the 1980s. Between 1995 and 2008, we sampled 640 C. parasitica isolates from nine populations south of the Alps and nine north of the Alps. Twelve historical isolates, collected between 1950 and 1972 in the south, were obtained from our collection. All 652 isolates were screened at 10 microsatellite loci to test for the existence of divergent genetic pools and to infer possible origins of haplotypes. In total, 52 haplotypes were identified. Structure software analysis indicated that 43 haplotypes (including all historical haplotypes) belonged to a main cluster, 6 haplotypes belonged to a different cluster, and 3 haplotypes had an intermediate allele pattern. All newly founded populations in northern Switzerland were initiated by one or just a few haplotypes from the main cluster, which probably came directly from the populations south of the Alps. Subsequently, genetic diversity increased through mutations, sexual reproduction, or new migrations. The highest increase in diversity was observed in populations where haplotypes from different genetic pools were encountered.
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Affiliation(s)
- S Prospero
- WSL Swiss Federal Research Institute, Birmensdorf, Switzerland.
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29
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Nydam ML, De Tomaso AW. Creation and maintenance of variation in allorecognition Loci: molecular analysis in various model systems. Front Immunol 2011; 2:79. [PMID: 22566868 PMCID: PMC3342096 DOI: 10.3389/fimmu.2011.00079] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 12/02/2011] [Indexed: 01/28/2023] Open
Abstract
Allorecognition is the ability of an organism to differentiate self or close relatives from unrelated conspecifics. Effective allorecognition systems are critical to the survival of organisms; they prevent inbreeding and facilitate fusions between close relatives. Where the loci governing allorecognition outcomes have been identified, the corresponding proteins often exhibit exceptional polymorphism. Two important questions about this polymorphism remain unresolved: how is it created, and how is it maintained. Because the genetic bases of several allorecognition systems have now been identified, including alr1 and alr2 in Hydractinia, fusion histocompatibility in Botryllus, the het (vic) loci in fungi, tgrB1 and tgrC1 in Dictyostelium, and self-incompatibility (SI) loci in several plant families, we are now poised to achieve a clearer understanding of how these loci evolve. In this review, we summarize what is currently known about the evolution of allorecognition loci, highlight open questions, and suggest future directions.
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Affiliation(s)
- Marie L Nydam
- Department of Molecular, Cellular and Developmental Biology, University of California Santa Barbara Santa Barbara, CA, USA.
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JEŽIĆ MARIN, KRSTIN LJILJANA, RIGLING DANIEL, ĆURKOVIĆ‐PERICA MIRNA. High diversity in populations of the introduced plant pathogen,
Cryphonectria parasitica
, due to encounters between genetically divergent genotypes. Mol Ecol 2011; 21:87-99. [DOI: 10.1111/j.1365-294x.2011.05369.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- MARIN JEŽIĆ
- Division of Biology, Faculty of Science, University of Zagreb, Marulićev trg 9a, HR‐10000 Zagreb, Croatia
| | - LJILJANA KRSTIN
- Department of Biology, University of J. J. Strossmayer in Osijek, Trg Lj. Gaja 6, HR‐31000 Osijek, Croatia
| | - DANIEL RIGLING
- WSL Swiss Federal Research Institute, Zürcherstrasse 111, CH‐8903 Birmensdorf, Switzerland
| | - MIRNA ĆURKOVIĆ‐PERICA
- Division of Biology, Faculty of Science, University of Zagreb, Marulićev trg 9a, HR‐10000 Zagreb, Croatia
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Molecular characterization of vegetative incompatibility genes that restrict hypovirus transmission in the chestnut blight fungus Cryphonectria parasitica. Genetics 2011; 190:113-27. [PMID: 22021387 PMCID: PMC3249360 DOI: 10.1534/genetics.111.133983] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Genetic nonself recognition systems such as vegetative incompatibility operate in many filamentous fungi to regulate hyphal fusion between genetically dissimilar individuals and to restrict the spread of virulence-attenuating mycoviruses that have potential for biological control of pathogenic fungi. We report here the use of a comparative genomics approach to identify seven candidate polymorphic genes associated with four vegetative incompatibility (vic) loci of the chestnut blight fungus Cryphonectria parasitica. Disruption of candidate alleles in one of two strains that were heteroallelic at vic2, vic6, or vic7 resulted in enhanced virus transmission, but did not prevent barrage formation associated with mycelial incompatibility. Detailed characterization of the vic6 locus revealed the involvement of nonallelic interactions between two tightly linked genes in barrage formation, heterokaryon formation, and asymmetric, gene-specific influences on virus transmission. The combined results establish molecular identities of genes associated with four C. parasitica vic loci and provide insights into how these recognition factors interact to trigger incompatibility and restrict virus transmission.
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32
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Brusini J, Robin C, Franc A. Parasitism and maintenance of diversity in a fungal vegetative incompatibility system: the role of selection by deleterious cytoplasmic elements. Ecol Lett 2011; 14:444-52. [PMID: 21382145 DOI: 10.1111/j.1461-0248.2011.01602.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In fungi, horizontal transmission of deleterious cytoplasmic elements is reduced by the vegetative incompatibility system. This self/non-self recognition system may select for greater diversity of fungal incompatibility phenotypes in a frequency-dependent manner but the link between the diversity of fungal phenotypes and the virulence of cytoplasmic parasites has been poorly studied. We used an epidemiological model to show that even when transmission between incompatibility types is permitted, parasite pressure can lead to high levels of polymorphism for vegetative incompatibility systems. Moreover, high levels of polymorphism in host populations can select for less virulent cytoplasmic parasites. This feedback mechanism between parasite virulence and vegetative incompatibility system polymorphism of host populations may account for the general avirulence of most known mycoviruses. Furthermore, this mechanism provides a new perspective on the particular ecology and evolution of the host/parasite interactions acting between fungi and their cytoplasmic parasites.
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Affiliation(s)
- Jérémie Brusini
- INRA, UMR 1202 Biodiversity, Genes & Communities, 69 Route d'Arcachon, F-33610 Cestas, France.
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33
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Popov AP, Belov AA, Ivanushkina NE, Tsvetkov IL, Konichev AS. Molecular genetic determinants of intraspecific polymorphism of the phytopathogenic fungus Cryphonectria parasitica. RUSS J GENET+ 2011. [DOI: 10.1134/s1022795411030112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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34
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ENGH INGEBORGBJORVAND, CARLSEN TOR, SAETRE GLENNPETER, HÖGBERG NILS, DOI SHUICHI, KAUSERUD HÅVARD. Two invasive populations of the dry rot fungusSerpula lacrymansshow divergent population genetic structures. Mol Ecol 2010; 19:706-15. [DOI: 10.1111/j.1365-294x.2009.04505.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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35
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Dutech C, Fabreguettes O, Capdevielle X, Robin C. Multiple introductions of divergent genetic lineages in an invasive fungal pathogen, Cryphonectria parasitica, in France. Heredity (Edinb) 2009; 105:220-8. [PMID: 19997121 DOI: 10.1038/hdy.2009.164] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The occurrence of multiple introductions may be a crucial factor in the successful establishment of invasive species, but few studies focus on the introduction of fungal pathogens, despite their significant effect on invaded habitats. Although Cryphonectria parasitica, the chestnut blight fungus introduced in North America and Europe from Asia during the 20th century, caused dramatic changes in its new range, the history of its introduction is not well retraced in Europe. Using 10 microsatellite loci, we investigated the genetic diversity of 583 isolates in France, where several introductions have been hypothesized. Our analyses showed that the seven most frequent multilocus genotypes belonged to three genetic lineages, which had a different and geographically limited distribution. These results suggest that different introduction events occurred in France. Genetic recombination was low among these lineages, despite the presence of the two mating types in each chestnut stand analysed. The spatial distribution of lineages suggests that the history of introductions in France associated with the slow expansion of the disease has contributed to the low observed rate of recombination among the divergent lineages. However, we discuss the possibility that environmental conditions or viral interactions could locally reduce recombination among genotypes.
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Affiliation(s)
- C Dutech
- INRA, UMR 1202 BIOGECO, Equipe de Pathologie Forestière, Domaine de Pierroton, Cestas, France.
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36
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The horizontal transmission of Cryphonectria hypovirus 1 (CHV1) is affected by virus strains. CHINESE SCIENCE BULLETIN-CHINESE 2009. [DOI: 10.1007/s11434-009-0368-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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37
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Milgroom MG, Sotirovski K, Risteski M, Brewer MT. Heterokaryons and parasexual recombinants of Cryphonectria parasitica in two clonal populations in southeastern Europe. Fungal Genet Biol 2009; 46:849-54. [PMID: 19643198 DOI: 10.1016/j.fgb.2009.07.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2009] [Revised: 07/22/2009] [Accepted: 07/23/2009] [Indexed: 11/27/2022]
Abstract
Evidence for parasexuality in natural populations of haploid fungi requires the demonstration of diploids or heterokaryons and recombinant genotypes in the absence of sex. We studied clonal populations of the chestnut blight fungus, Cryphonectria parasitica, in southeastern Europe and found evidence of parasexuality in two locations. In Osoj, Macedonia, we found one isolate (Os05-66) that had two alleles at six codominant loci, giving a haplotype that was a composite of two clones in this population. Six single-conidial isolates from Os05-66 had two alleles at some loci, suggesting partial diploidy or aneuploidy, and we found four recombinant haplotypes among single-conidial isolates from hyphal-tip isolates of the same isolate. In Teano, Italy, we found two heterokaryon isolates that were partial composites of two dominant clones. Single-conidial isolates from hyphal-tip isolates had recombinant haplotypes. These results provide evidence that is consistent with the hypothesis of parasexuality in C. parasitica in Europe, similar to an earlier report in a natural population in the USA.
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Affiliation(s)
- Michael G Milgroom
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA.
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38
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Chevanne D, Bastiaans E, Debets A, Saupe SJ, Clavé C, Paoletti M. Identification of the het-r vegetative incompatibility gene of Podospora anserina as a member of the fast evolving HNWD gene family. Curr Genet 2009; 55:93-102. [PMID: 19137300 DOI: 10.1007/s00294-008-0227-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Revised: 12/18/2008] [Accepted: 12/18/2008] [Indexed: 01/08/2023]
Abstract
In fungi, vegetative incompatibility is a conspecific non-self recognition mechanism that restricts formation of viable heterokaryons when incompatible alleles of specific het loci interact. In Podospora anserina, three non-allelic incompatibility systems have been genetically defined involving interactions between het-c and het-d, het-c and het-e, het-r and het-v. het-d and het-e are paralogues belonging to the HNWD gene family that encode proteins of the STAND class. HET-D and HET-E proteins comprise an N-terminal HET effector domain, a central GTP binding site and a C-terminal WD repeat domain constituted of tandem repeats of highly conserved WD40 repeat units that define the specificity of alleles during incompatibility. The WD40 repeat units of the members of this HNWD family are undergoing concerted evolution. By combining genetic analysis and gain of function experiments, we demonstrate that an additional member of this family, HNWD2, corresponds to the het-r non-allelic incompatibility gene. As for het-d and het-e, allele specificity at the het-r locus is determined by the WD repeat domain. Natural isolates show allelic variation for het-r.
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Affiliation(s)
- Damien Chevanne
- Laboratoire de Génétique Moléculaire des Champignons, IBGC, UMR5095, Université Victor Segalen Bordeaux2 et CNRS, 1 rue Camille Saint-Saëns, 33077, Bordeaux Cedex, France
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39
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Milgroom MG, Sotirovski K, Spica D, Davis JE, Brewer MT, Milev M, Cortesi P. Clonal population structure of the chestnut blight fungus in expanding ranges in southeastern Europe. Mol Ecol 2008; 17:4446-58. [PMID: 18803594 DOI: 10.1111/j.1365-294x.2008.03927.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Expanding populations are often less genetically diverse at their margins than at the centre of a species' range. Established, older populations of the chestnut blight fungus, Cryphonectria parasitica, are more variable for vegetative compatibility (vc) types than in expanding populations in southeastern Europe where C. parasitica has colonized relatively recently. To test whether vc types represent clones, we genotyped 373 isolates of C. parasitica from southern Italy, Romania, Bulgaria, Macedonia, Greece and Turkey using 11 sequence-characterized amplified region (SCAR) markers. Ten SCAR loci and six vegetative incompatibility (vic) loci were polymorphic in these samples. These populations are clonal by all criteria tested: (i) among 373 isolates, we found only eight multilocus haplotypes, and the same haplotypes were found in multiple countries, sometimes separated in time by as much as 12 years; (ii) the number of haplotypes observed was significantly less than expected under random mating; (iii) populations are in linkage disequilibrium; (iv) the two sets of independent markers, SCARs and vc types, are highly correlated; and (v) sexual structures of C. parasitica were found only in Bulgaria and Romania. One mating type (MAT-1) was found in 98% of the isolates sampled. In contrast, a population in northern Italy, in the central part of the range in Europe, had 12 multilocus haplotypes among 19 isolates. The spread of a few clones could be the result either of founder effect and restricted migration, or these clones have greater fitness than others and spread because they are better adapted to conditions in southeastern Europe.
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Affiliation(s)
- Michael G Milgroom
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA.
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40
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Carter LLA, Leslie JF, Webster RK. Population structure of Fusarium fujikuroi from California rice and water grass. PHYTOPATHOLOGY 2008; 98:992-8. [PMID: 18943737 DOI: 10.1094/phyto-98-9-0992] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The recent observance of Fusarium fujikuroi, the causal agent of Bakanae disease of rice, in California provides a unique opportunity to assess the population diversity of an introduced pathogen in a new environment. We collected 172 isolates of this pathogen between 2000 and 2003 from California rice and two from water grass (Echinochloa spp.). Pathogenicity of F. fujikuroi was demonstrated on early water grass (E. oryzoides) and barnyard grass (E. crus-galli) indicating that weed control should be part of Bakanae management programs. Both mating types and six unique amplified fragment length polymorphism haplotypes corresponding to six identified vegetative compatibility groups were detected. The two most frequently isolated haplotypes encompassed 94% of the collected isolates, suggesting that clonal reproduction dominates. Coefficients of similarity between the unique haplotypes ranged from 0.94 to 0.98, and indicate that there is very little genotypic variation in the F. fujikuroi population in California. The near fixation of the MAT-1 idiomorph (observed ratio 170 MAT-1:4 MAT-2), is consistent with a hypothesis of predominant or exclusive asexual reproduction. The low level of introduced genotypic diversity, in conjunction with the asexual reproductive strategy of this population will slow evolutionary processes, including adaptation to the California environment.
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Affiliation(s)
- L L A Carter
- Department of Plant Pathology, Throckmorton Plant Sciences Center, Kansas State University, Manhattan 66506.
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41
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van der Nest MA, Slippers B, Stenlid J, Wilken PM, Vasaitis R, Wingfield MJ, Wingfield BD. Characterization of the systems governing sexual and self-recognition in the white rot homobasidiomycete Amylostereum areolatum. Curr Genet 2008; 53:323-36. [DOI: 10.1007/s00294-008-0188-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2008] [Revised: 03/10/2008] [Accepted: 03/11/2008] [Indexed: 10/22/2022]
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42
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Jo YK, Chang SW, Rees J, Jung G. Reassessment of vegetative compatibility of Sclerotinia homoeocarpa using nitrate-nonutilizing mutants. PHYTOPATHOLOGY 2008; 98:108-114. [PMID: 18943245 DOI: 10.1094/phyto-98-1-0108] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Nitrate-nonutilizing (nit) mutants were recovered for the first time from 21 isolates of Sclerotinia homoeocarpa collected in the United States. Mutants were selected from shredded mycelium of each isolate when cultured on water agar medium amended with 4% (wt/vol) potassium chlorate. The mutants could be classified into three phenotypes: nit1, nit3, and NitM, based on their growth on minimal medium (Czapek solution agar) supplemented with NaNO(2) or hypoxanthine. Complementary heterokaryons were observed in pairings between different phenotypes of nit mutants derived from compatible isolates, but not in self-fusions or pairings between incompatible isolates. The vigor of prototrophic growth varied with isolates and mutant phenotypes. Strong and continuous heterokaryons, as well as weak and spontaneous ones, formed depending on pairings of nit mutants. Stable heterokaryons between compatible isolates, but apoptotic reactions between incompatible isolates, were observed immediately after hyphal fusion under the epifluorescence microscope. The 21 isolates used in this study, which were previously assigned into 11 different vegetative compatibility groups (VCGs) based on the formation of a barrage zone at the contact site of paired isolates on complete medium (potato dextrose agar), were regrouped into five VCGs based on heterokaryon formation between nit mutants on minimal medium.
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Affiliation(s)
- Y-K Jo
- Department of Plant, Soil and Insects Sciences, University of Massachusets, Amherst 01003, USA
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43
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Rossman AY, Farr DF, Castlebury LA. A review of the phylogeny and biology of the Diaporthales. MYCOSCIENCE 2007. [DOI: 10.1007/s10267-007-0347-7] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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44
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Yan B, Li Z, Huang H, Qin L. Genetic diversity and population differentiation of chestnut blight fungus, Cryphonectria parasitica, in China as revealed by RAPD. Biochem Genet 2007; 45:487-506. [PMID: 17497221 DOI: 10.1007/s10528-007-9090-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2006] [Accepted: 01/27/2007] [Indexed: 10/23/2022]
Abstract
Seventeen Cryphonectria parasitica populations sampled from six regions in China were investigated using RAPD. Across all 169 isolates from the 17 populations evaluated, 52 of the 71 markers (73%) were polymorphic, total genetic diversity (h) was 0.1463, and Shannon's index was 0.2312. Diversity within populations accounted for 74% of total genetic diversity, and genetic differentiation among populations was 0.26 (G (ST) = 0.26). Gene flow was 1.4 among the populations; higher gene flow was found among populations within regions and among regions [N (m) (G (SR)) = 2.8 and N (m) (G (RT)) = 3.5]. The unweighted pair group mean analysis (UPGMA) dendrogram revealed two distinct clusters: the northern China group and the southern China group. The spatial autocorrelation analysis revealed that the variation at most loci was randomly distributed and lacked spatial structure, but several loci and closer distances were spatially structured. Human activity and habitat could also be important factors affecting genetic structure among C. parasitica populations in China. Genetic diversity was highest in Southwest China, descending in an orderly fashion to Northeast China. This pattern indicated that Southwest China might be the center of origin of C. parasitica in China. The present study provides useful information for understanding the origin and spread of chestnut blight fungus in China and valuable data for formulating relevant strategies for controlling the disease in China.
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Affiliation(s)
- Boqian Yan
- Wuhan Botanical Garden, Chinese Academy of Sciences, Moshan, Wuhan, Hubei, 430074, PR China
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Prospero S, Conedera M, Heiniger U, Rigling D. Saprophytic Activity and Sporulation of Cryphonectria parasitica on Dead Chestnut Wood in Forests with Naturally Established Hypovirulence. PHYTOPATHOLOGY 2006; 96:1337-44. [PMID: 18943666 DOI: 10.1094/phyto-96-1337] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
ABSTRACT Sustainable biological control of the chestnut blight fungus Crypho-nectria parasitica with hypovirulence depends on the production and dissemination of hypovirus-infected propagules of the pathogen. We investigated the ability of C. parasitica to sporulate and produce hypo-virus-infected spores on recently dead chestnut wood in coppice stands in southern Switzerland where hypovirulence has been naturally established. The number and type (active, inactive, or none) of cankers was assessed on experimentally cut and stacked stems, firewood stacks, and natural dead wood. Hypovirus-free and hypovirus-infected strains readily survived for more than 1 year in the chestnut blight cankers of the stacked stems. Sporulation of C. parasitica was observed on the surface of preexisting inactive and active cankers, as well as on newly colonized bark areas and was significantly more abundant than on comparable cankers on living stems. On all types of dead wood, we observed more stromata with perithecia than with pycnidia; however, a large proportion of the stromata was not differentiated. All perithecia examined yielded only hypovirus-free ascospores. The incidence of pycnidia that produced hypovirus-infected conidia ranged from 5% on natural dead wood to 41% on the experimental stacks. The mean virus transmission rate into conidia was 69%. Our study demonstrates a considerable saprophytic activity of C. parasitica on recently dead chestnut wood and supports the hypothesis of a role of this saprophytic phase in the epidemiology of hypovirulence.
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Park Y, Chen X, Punja ZK. Molecular and Biological Characterization of a Mitovirus in Chalara elegans (Thielaviopsis basicola). PHYTOPATHOLOGY 2006; 96:468-79. [PMID: 18944306 DOI: 10.1094/phyto-96-0468] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
ABSTRACT A 2.8-kb double-stranded RNA (dsRNA) element in strain BK18 of Chalara elegans originally isolated from cotton soil in California was characterized by obtaining a full-length cDNA sequence (2,896 nucleotides in length) from a series of overlapping clones. Sequence analysis revealed the presence of one large open reading frame (ORF I) using the mitochondrial genetic code, with 20 to 34% amino acid identity to the ORF I of other previously reported fungal mitochondrial RNA viruses. The ORF I encoded a putative protein of 705 amino acids and contained the conserved motif characteristic of RNA-dependent RNA polymerases. Purification of mitochondria from strain BK18 confirmed the co-localization of this dsRNA, and northern blot hybridization with a strand-specific probe revealed the (+) single-stranded nature. This Chalara elegans mitovirus (CeMV) is designated as a new member of the genus Mitovirus of the family Narnaviridae. Using dsRNA-specific primers, the ORF I region (positions 427 to 2544) was obtained from an additional 2.8-kb dsRNA element in strain HA2 originating from carrot roots in the Netherlands. Both ORFs had 98% homology at the nucleotide and amino acid levels. CeMV was also found to be present in five additional strains of C. elegans from different geographic locations worldwide, and a 97 to 100% nucleotide sequence identity was observed within a 300-bp region of ORF I in these strains. To determine the biological effects of CeMV on C. elegans, attempts to cure strain BK18 of the dsRNA were made. Sequential transfers of mycelium at 35 to 37 degrees C yielded a colony which lacked the 2.8-kb dsRNA when visualized on agarose gels and also in northern blot hybridization analysis. However, reverse transcription-polymerase chain reaction with specific primer sets revealed a band, indicating that dsRNA replication had been significantly repressed (latent). The wild type and latently infected strains were compared for colony morphology, growth rate, melanin production, various enzymatic assays (polyphenoloxidase, laccase, tyrosinase, and esterase), and virulence on carrot roots. Colony morphology on V8 agar was comparable between the two strains, while growth rate, melanin production, and virulence were enhanced in the latently infected strain. There were no detectable differences in enzymatic activity. Transmission electron microscopy of hyphae of the wild type and latently infected strains revealed differences in the number and size of the mitochondria, which were enhanced in the latently infected strain. Our results show that CeMV is a new member of the genus Mitovirus with some disruptive effects on its fungal host and is present in C. elegans strains from different locations worldwide.
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Breuillin F, Dutech C, Robin C. Genetic diversity of the Chestnut blight fungus Cryphonectria parasitica in four French populations assessed by microsatellite markers. ACTA ACUST UNITED AC 2006; 110:288-96. [PMID: 16377166 DOI: 10.1016/j.mycres.2005.09.016] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2005] [Revised: 09/09/2005] [Accepted: 09/25/2005] [Indexed: 11/25/2022]
Abstract
Microsatellites are powerful markers to infer population genetic parameters. Here, 13 microsatellite loci isolated from a genomic and a cDNA library of Cryphonectria parasitica were used to characterize the genetic diversity and structure of four French populations. Twelve of these loci were polymorphic within populations, and average gene diversity (H(e)) was estimated to be 0.35. There was a lower genetic diversity in a south-eastern population relative to three south-western populations. In these three populations, microsatellite genotypic diversity was higher than vegetative compatibility type diversity. A high genetic differentiation (G(ST) = 0.27) suggested a low gene flow and/or founder effects of French populations which are in agreement with low dispersal of spores and different introductions of this species in southern France. This study demonstrates the significance of these microsatellite loci to assess gene flow and reproductive system in this important pathogen.
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Affiliation(s)
- Florence Breuillin
- Institut National de la Recherche Agronomique, Unité Mixte de Recherche BIOGECO, Equipe de Pathologie Forestière, Domaine de la Grande Ferrade, 71 Villenave d'Ornon, France
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McGuire IC, Davis JE, Double ML, MacDonald WL, Rauscher JT, McCawley S, Milgroom MG. Heterokaryon formation and parasexual recombination between vegetatively incompatible lineages in a population of the chestnut blight fungus, Cryphonectria parasitica. Mol Ecol 2006; 14:3657-69. [PMID: 16202087 DOI: 10.1111/j.1365-294x.2005.02693.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Heterokaryosis was recently reported in the chestnut blight fungus, Cryphonectria parasitica, in which individuals contain nuclei that are isogenic except at the mating-type locus (MAT). MAT heterokaryons were found in several natural populations, including a putatively clonal population in West Salem, Wisconsin, providing an opportunity to address the question of how heterokaryons arise. We represented relationships among RFLP fingerprint haplotypes as networks in which loop formation is considered evidence of recombination. From 1990 to 1995, this population was clonal, as indicated by a simple haplotype network without loops, and the correlation of vegetative compatibility (vc) types and mating types with haplotype lineages. By 1999, we observed loops in the haplotype network involving isolates of two vc types (WS-2 and WS-3). Isolates with haplotypes in the loops were either MAT heterokaryons, carried the opposite mating type from other isolates of the same vc type, and/or had two alleles at two or more codominant SCAR (sequence-characterized amplified region) loci. Segregation of markers and recombination were evident among single-spore isolates from one heterokaryon; these single-spore isolates had novel fingerprint haplotypes, also within the loops. In contrast, vc type WS-1, which comprises 85% of the population, was represented by a simple network with no loops, indicating a clonal lineage varying only by mutation. Almost all isolates of WS-1 had the same mating type; the exceptions were five isolates that were MAT heterokaryons. These results are consistent with the hypothesis that heterokaryons formed between vegetatively incompatible individuals, and recombination occurred by a parasexual process.
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Affiliation(s)
- I C McGuire
- Department of Plant Pathology, Cornell University, Ithaca, NY 14853, USA
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Giovannetti M, Avio L, Fortuna P, Pellegrino E, Sbrana C, Strani P. At the root of the wood wide web: self recognition and non-self incompatibility in mycorrhizal networks. PLANT SIGNALING & BEHAVIOR 2006; 1:1-5. [PMID: 19521468 PMCID: PMC2633692 DOI: 10.4161/psb.1.1.2277] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2005] [Accepted: 10/31/2005] [Indexed: 05/11/2023]
Abstract
Arbuscular mycorrhizal (AM) fungi are mutualistic symbionts living in the roots of 80% of land plant species, and developing extensive, below-ground extraradical hyphae fundamental for the uptake of soil nutrients and their transfer to host plants. Since AM fungi have a wide host range, they are able to colonize and interconnect contiguous plants by means of hyphae extending from one root system to another. Such hyphae may fuse due to the widespread occurrence of anastomoses, whose formation depends on a highly regulated mechanism of self recognition. Here, we examine evidences of self recognition and non-self incompatibility in hyphal networks formed by AM fungi and discuss recent results showing that the root systems of plants belonging to different species, genera and families may be connected by means of anastomosis formation between extraradical mycorrhizal networks, which can create indefinitely large numbers of belowground fungal linkages within plant communities.
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Affiliation(s)
| | - Luciano Avio
- Institute of Biology and Agriculture Biotechnology; CNR; UO Pisa; Pisa, Italy
| | - Paola Fortuna
- Department of Crop Plant Biology; CNR; UO Pisa; Pisa, Italy
| | | | - Cristiana Sbrana
- Institute of Biology and Agriculture Biotechnology; CNR; UO Pisa; Pisa, Italy
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Fedorova ND, Badger JH, Robson GD, Wortman JR, Nierman WC. Comparative analysis of programmed cell death pathways in filamentous fungi. BMC Genomics 2005; 6:177. [PMID: 16336669 PMCID: PMC1325252 DOI: 10.1186/1471-2164-6-177] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2005] [Accepted: 12/08/2005] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Fungi can undergo autophagic- or apoptotic-type programmed cell death (PCD) on exposure to antifungal agents, developmental signals, and stress factors. Filamentous fungi can also exhibit a form of cell death called heterokaryon incompatibility (HI) triggered by fusion between two genetically incompatible individuals. With the availability of recently sequenced genomes of Aspergillus fumigatus and several related species, we were able to define putative components of fungi-specific death pathways and the ancestral core apoptotic machinery shared by all fungi and metazoa. RESULTS Phylogenetic profiling of HI-associated proteins from four Aspergilli and seven other fungal species revealed lineage-specific protein families, orphan genes, and core genes conserved across all fungi and metazoa. The Aspergilli-specific domain architectures include NACHT family NTPases, which may function as key integrators of stress and nutrient availability signals. They are often found fused to putative effector domains such as Pfs, SesB/LipA, and a newly identified domain, HET-s/LopB. Many putative HI inducers and mediators are specific to filamentous fungi and not found in unicellular yeasts. In addition to their role in HI, several of them appear to be involved in regulation of cell cycle, development and sexual differentiation. Finally, the Aspergilli possess many putative downstream components of the mammalian apoptotic machinery including several proteins not found in the model yeast, Saccharomyces cerevisiae. CONCLUSION Our analysis identified more than 100 putative PCD associated genes in the Aspergilli, which may help expand the range of currently available treatments for aspergillosis and other invasive fungal diseases. The list includes species-specific protein families as well as conserved core components of the ancestral PCD machinery shared by fungi and metazoa.
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Affiliation(s)
- Natalie D Fedorova
- The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20850, USA
| | - Jonathan H Badger
- The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20850, USA
| | - Geoff D Robson
- Faculty of Life Sciences, 1.800 Stopford Building, University of Manchester, Manchester M13 9PT, UK
| | - Jennifer R Wortman
- The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20850, USA
| | - William C Nierman
- The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20850, USA
- The George Washington University School of Medicine, Department of Biochemistry and Molecular Biology, 2300 Eye Street, NW Washington, DC 20837, USA
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