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Chai H, Liu P, Ma Y, Chen W, Tao N, Zhao Y. Characterization of Vegetative Incompatibility in Morchella importuna and Location of the Related-Genes by Bulk Segregant Analysis. Front Microbiol 2022; 13:828514. [PMID: 35330770 PMCID: PMC8940278 DOI: 10.3389/fmicb.2022.828514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 01/31/2022] [Indexed: 12/04/2022] Open
Abstract
Vegetative incompatibility (VI) is a widespread phenomenon developed in Morchella importuna, a species of ascomycete fungus that is cultivated on a rapidly expanding scale in China. Understanding the genetic bases of this nonself-recognition phenomenon is beneficial for resolving some problems that are associated with the production of this highly prized edible fungus, such as crossbreeding, strain classification, and pathogen transmission. VI is genetically controlled by het genes, organized in two different systems, namely allelic and nonallelic. These het genes have been well characterized in Podospora anserina and Neurospora crassa. In this work, putative het-homologs were identified in the genome of M. importuna, but their low allelic polymorphism in different vegetative compatibility groups (VCGs) suggested that VI in this fungus might not be regulated by these het genes. The progeny derived from vegetative compatible parents became a VCG, while the single-ascospore strains from vegetative incompatible parents were divided into four VCGs, and the interaction between the inter-group strains led to the formation of two types of barrages, viz., thin dark line and raised aggregate of hyphae. The Bulk Segregant Analysis confirmed that the genes mimpvic32 and mimpvic33 were linked to VI reactions in M. importuna; nevertheless, the formation of barrages also occurred between the pairs carrying the same allele of these two genes. In sum, the VI control system in M. importuna was complicated, and there were more other allelic or non-allelic VI-related genes.
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Affiliation(s)
- Hongmei Chai
- Biotechnology and Germplasmic Resource Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, China.,Yunnan Provincial Key Laboratory of Agricultural Biotechnology, Kunming, China.,Key Laboratory of Southwestern Crop Resource Germplasm Innovation, Ministry of Agriculture and Rural Affairs, Kunming, China
| | - Ping Liu
- Biotechnology and Germplasmic Resource Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, China.,Yunnan Provincial Key Laboratory of Agricultural Biotechnology, Kunming, China.,Key Laboratory of Southwestern Crop Resource Germplasm Innovation, Ministry of Agriculture and Rural Affairs, Kunming, China
| | - Yuanhao Ma
- Biotechnology and Germplasmic Resource Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, China.,Yunnan Provincial Key Laboratory of Agricultural Biotechnology, Kunming, China.,Key Laboratory of Southwestern Crop Resource Germplasm Innovation, Ministry of Agriculture and Rural Affairs, Kunming, China
| | - Weimin Chen
- Biotechnology and Germplasmic Resource Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, China.,Yunnan Provincial Key Laboratory of Agricultural Biotechnology, Kunming, China.,Key Laboratory of Southwestern Crop Resource Germplasm Innovation, Ministry of Agriculture and Rural Affairs, Kunming, China
| | - Nan Tao
- Biotechnology and Germplasmic Resource Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, China.,Yunnan Provincial Key Laboratory of Agricultural Biotechnology, Kunming, China.,Key Laboratory of Southwestern Crop Resource Germplasm Innovation, Ministry of Agriculture and Rural Affairs, Kunming, China
| | - Yongchang Zhao
- Biotechnology and Germplasmic Resource Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, China.,Yunnan Provincial Key Laboratory of Agricultural Biotechnology, Kunming, China.,Key Laboratory of Southwestern Crop Resource Germplasm Innovation, Ministry of Agriculture and Rural Affairs, Kunming, China
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2
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Spontaneous changes in somatic compatibility in Fusarium circinatum. Fungal Biol 2021; 125:725-732. [PMID: 34420699 DOI: 10.1016/j.funbio.2021.04.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Revised: 04/08/2021] [Accepted: 04/26/2021] [Indexed: 11/24/2022]
Abstract
Filamentous fungi grow by the elaboration of hyphae, which may fuse to form a network as a colony develops. Fusion of hyphae can occur between genetically different individuals, provided they share a common allele at loci affecting somatic compatibility. Diversity in somatic compatibility phenotypes reduces the frequency of hyphal fusion in a population, thereby slowing the spread of deleterious genetic elements such as viruses and plasmids, which require direct cytoplasmic contact for transmission. Diverse somatic compatibility phenotypes can be generated by recombining alleles through sexual reproduction, but this mechanism may not fully account for the diversity found in nature. For example, multiple compatibility phenotypes of Fusarium circinatum were shown to be associated with the same clonal lineage, which implies they were derived by a mutation rather than recombination through sexual reproduction. Experimental tests of this hypothesis confirmed that spontaneous changes in somatic compatibility can occur at a frequency between 5 and 8 per million spores. Genomic analysis of F. circinatum strains with altered somatic compatibility revealed no consistent evidence of recombination and supported the hypothesis that a spontaneous mutation generated the observed phenotypic change. Genes known to be involved in somatic compatibility had no mutations, suggesting that mutation occurred in a gene with an as yet unexplored function in somatic compatibility.
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3
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Yow AG, Zhang Y, Bansal K, Eacker SM, Sullivan S, Liachko I, Cubeta MA, Rollins JA, Ashrafi H. Genome sequence of Monilinia vaccinii-corymbosi sheds light on mummy berry disease infection of blueberry and mating type. G3-GENES GENOMES GENETICS 2021; 11:6062400. [PMID: 33598705 PMCID: PMC8022979 DOI: 10.1093/g3journal/jkaa052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 10/29/2020] [Indexed: 11/22/2022]
Abstract
Mummy berry disease, caused by the fungal pathogen Monilinia vaccinii-corymbosi (Mvc), is one of the most economically important diseases of blueberries in North America. Mvc is capable of inducing two separate blighting stages during its life cycle. Infected fruits are rendered mummified and unmarketable. Genomic data for this pathogen is lacking, but could be useful in understanding the reproductive biology of Mvc and the mechanisms it deploys to facilitate host infection. In this study, PacBio sequencing and Hi-C interaction data were utilized to create a chromosome-scale reference genome for Mvc. The genome comprises nine chromosomes with a total length of 30 Mb, an N50 length of 4.06 Mb, and an average 413X sequence coverage. A total of 9399 gene models were predicted and annotated, and BUSCO analysis revealed that 98% of 1,438 searched conserved eukaryotic genes were present in the predicted gene set. Potential effectors were identified, and the mating-type (MAT) locus was characterized. Biotrophic effectors allow the pathogen to avoid recognition by the host plant and evade or mitigate host defense responses during the early stages of fruit infection. Following locule colonization, necrotizing effectors promote the mummification of host tissues. Potential biotrophic effectors utilized by Mvc include chorismate mutase for reducing host salicylate and necrotrophic effectors include necrosis-inducing proteins and hydrolytic enzymes for macerating host tissue. The MAT locus sequences indicate the potential for homothallism in the reference genome, but a deletion allele of the MAT locus, characterized in a second isolate, indicates heterothallism. Further research is needed to verify the roles of individual effectors in virulence and to determine the role of the MAT locus in outcrossing and population genotypic diversity.
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Affiliation(s)
- Ashley G Yow
- Department of Horticultural Science, North Carolina State University, Raleigh, NC 27695, USA
| | - Yucheng Zhang
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA
| | - Kamaldeep Bansal
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA
| | | | | | | | - Marc A Cubeta
- Department of Entomology and Plant Pathology, Center for Integrated Fungal Research, North Carolina State University, Raleigh, NC 27606, USA
| | - Jeffrey A Rollins
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA
| | - Hamid Ashrafi
- Department of Horticultural Science, North Carolina State University, Raleigh, NC 27695, USA
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Ament-Velásquez SL, Johannesson H, Giraud T, Debuchy R, Saupe SJ, Debets AJ, Bastiaans E, Malagnac F, Grognet P, Peraza-Reyes L, Gladieux P, Kruys Å, Silar P, Huhndorf SM, Miller AN, Vogan AA. The taxonomy of the model filamentous fungus Podospora anserina. MycoKeys 2020; 75:51-69. [PMID: 33281477 PMCID: PMC7710671 DOI: 10.3897/mycokeys.75.55968] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 08/11/2020] [Indexed: 11/17/2022] Open
Abstract
The filamentous fungus Podospora anserina has been used as a model organism for more than 100 years and has proved to be an invaluable resource in numerous areas of research. Throughout this period, P. anserina has been embroiled in a number of taxonomic controversies regarding the proper name under which it should be called. The most recent taxonomic treatment proposed to change the name of this important species to Triangularia anserina. The results of past name changes of this species indicate that the broader research community is unlikely to accept this change, which will lead to nomenclatural instability and confusion in literature. Here, we review the phylogeny of the species closely related to P. anserina and provide evidence that currently available marker information is insufficient to resolve the relationships amongst many of the lineages. We argue that it is not only premature to propose a new name for P. anserina based on current data, but also that every effort should be made to retain P. anserina as the current name to ensure stability and to minimise confusion in scientific literature. Therefore, we synonymise Triangularia with Podospora and suggest that either the type species of Podospora be moved to P. anserina from P. fimiseda or that all species within the Podosporaceae be placed in the genus Podospora.
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Affiliation(s)
- S. Lorena Ament-Velásquez
- Systematic Biology, Department of Organismal Biology, Uppsala University, Norbyvägen 18D, 752 36 Uppsala, SwedenUppsala UniveristyUppsalaSweden
| | - Hanna Johannesson
- Systematic Biology, Department of Organismal Biology, Uppsala University, Norbyvägen 18D, 752 36 Uppsala, SwedenUppsala UniveristyUppsalaSweden
| | - Tatiana Giraud
- Ecologie Systématique Evolution, CNRS, Université Paris-Saclay, AgroParisTech, 91400, Orsay, FranceUniversité Paris-SaclayOrsayFrance
| | - Robert Debuchy
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, FranceUniversité Paris-SaclayGif-sur-YvetteFrance
| | - Sven J. Saupe
- IBGC, UMR 5095, CNRS Université de Bordeaux, 1 rue Camille Saint Saëns, 33077, Bordeaux, FranceUniversité de BordeauxBordeauxFrance
| | - Alfons J.M. Debets
- Laboratory of Genetics, Wageningen University, Arboretumlaan 4, 6703 BD, Wageningen, NetherlandsWageningen UniversityWageningenNetherlands
| | - Eric Bastiaans
- Laboratory of Genetics, Wageningen University, Arboretumlaan 4, 6703 BD, Wageningen, NetherlandsWageningen UniversityWageningenNetherlands
| | - Fabienne Malagnac
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, FranceUniversité Paris-SaclayGif-sur-YvetteFrance
| | - Pierre Grognet
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, FranceUniversité Paris-SaclayGif-sur-YvetteFrance
| | - Leonardo Peraza-Reyes
- Instituto de Fisiología Celular, Departamento de Bioquímica y Biología Estructural, Universidad Nacional Autónoma de México, Mexico City, MexicoUniversidad Nacional Autónoma de MéxicoMexico CityMexico
| | - Pierre Gladieux
- UMR BGPI, Université de Montpellier, INRAE, CIRAD, Institut Agro, F-34398, Montpellier, FranceUniversité de MontpellierMontpellierFrance
| | - Åsa Kruys
- Museum of Evolution, Botany, Uppsala University, Norbyvägen 18, 752 36, Uppsala, SwedenUppsala UniversityUppsalaSweden
| | - Philippe Silar
- Université de Paris, Laboratoire Interdisciplinaire des Energies de Demain (LIED), F-75006, Paris, FranceUniversité de ParisParisFrance
| | - Sabine M. Huhndorf
- Botany Department, The Field Museum, Chicago, Illinois 60605, USAThe Field MuseumChicagoUnited States of America
| | - Andrew N. Miller
- Illinois Natural History Survey, University of Illinois, Champaign, IL 61820, USAUniversity of IllinoisChampaignUnited States of America
| | - Aaron A. Vogan
- Systematic Biology, Department of Organismal Biology, Uppsala University, Norbyvägen 18D, 752 36 Uppsala, SwedenUppsala UniveristyUppsalaSweden
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6
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Terruzzi L, Spagnolli G, Boldrini A, Requena JR, Biasini E, Faccioli P. All-atom simulation of the HET-s prion replication. PLoS Comput Biol 2020; 16:e1007922. [PMID: 32946455 PMCID: PMC7526898 DOI: 10.1371/journal.pcbi.1007922] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 09/30/2020] [Accepted: 08/03/2020] [Indexed: 11/18/2022] Open
Abstract
Prions are self-replicative protein particles lacking nucleic acids. Originally discovered for causing infectious neurodegenerative disorders, they have also been found to play several physiological roles in a variety of species. Functional and pathogenic prions share a common mechanism of replication, characterized by the ability of an amyloid conformer to propagate by inducing the conversion of its physiological, soluble counterpart. Since time-resolved biophysical experiments are currently unable to provide full reconstruction of the physico-chemical mechanisms responsible for prion replication, one must rely on computer simulations. In this work, we show that a recently developed algorithm called Self-Consistent Path Sampling (SCPS) overcomes the computational limitations of plain MD and provides a viable tool to investigate prion replication processes using state-of-the-art all-atom force fields in explicit solvent. First, we validate the reliability of SCPS simulations by characterizing the folding of a class of small proteins and comparing against the results of plain MD simulations. Next, we use SCPS to investigate the replication of the prion forming domain of HET-s, a physiological fungal prion for which high-resolution structural data are available. Our atomistic reconstruction shows remarkable similarities with a previously reported mechanism of mammalian PrPSc propagation obtained using a simpler and more approximate path sampling algorithm. Together, these results suggest that the propagation of prions generated by evolutionary distant proteins may share common features. In particular, in both these cases, prions propagate their conformation through a very similar templating mechanism. Prions are proteins capable of replicating in absence of nucleic acids. By propagating the information encoded in their conformation, prions exemplify the phenomenon of protein-based inheritance. These peculiar agents are associated with neurodegenerative pathologies in mammals, but also involved in a wide variety of physiological processes occurring in various biological contexts along the evolutionary scale. In this work, we apply a recently developed computational method to study the propagation mechanism of the fungal prion HET-s, using a realistic all-atom model. We find that the replication of HET-s shares fundamental features with the templated conversion of the mammalian prion PrPSc.
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Affiliation(s)
- Luca Terruzzi
- Sibylla Biotech SRL, Verona, Italy.,Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Povo, Trento, Italy
| | - Giovanni Spagnolli
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Povo, Trento, Italy.,Dulbecco Telethon Institute, University of Trento, Povo, Trento, Italy
| | - Alberto Boldrini
- Sibylla Biotech SRL, Verona, Italy.,Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Povo, Trento, Italy
| | - Jesús R Requena
- CIMUS Biomedical Research Institute & Department of Medical Sciences, University of Santiago de Compostela-IDIS, Spain
| | - Emiliano Biasini
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Povo, Trento, Italy.,Dulbecco Telethon Institute, University of Trento, Povo, Trento, Italy
| | - Pietro Faccioli
- Department of Physics, University of Trento, Povo, Trento, Italy.,INFN-TIFPA, University of Trento, Povo, Trento, Italy
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7
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Daskalov A, Gladieux P, Heller J, Glass NL. Programmed Cell Death in Neurospora crassa Is Controlled by the Allorecognition Determinant rcd-1. Genetics 2019; 213:1387-1400. [PMID: 31636083 PMCID: PMC6893366 DOI: 10.1534/genetics.119.302617] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Accepted: 10/17/2019] [Indexed: 12/31/2022] Open
Abstract
Nonself recognition following cell fusion between genetically distinct individuals of the same species in filamentous fungi often results in a programmed cell death (PCD) reaction, where the heterokaryotic fusion cell is compartmentalized and rapidly killed. The allorecognition process plays a key role as a defense mechanism that restricts genome exploitation, resource plundering, and the spread of deleterious senescence plasmids and mycoviruses. Although a number of incompatibility systems have been described that function in mature hyphae, less is known about the PCD pathways in asexual spores, which represent the main infectious unit in various human and plant fungal pathogens. Here, we report the identification of regulator of cell death-1 (rcd-1), a novel allorecognition gene, controlling PCD in germinating asexual spores of Neurospora crassa; rcd-1 is one of the most polymorphic genes in the genomes of wild N. crassa isolates. The coexpression of two antagonistic rcd-1-1 and rcd-1-2 alleles was necessary and sufficient to trigger cell death in fused germlings and in hyphae. Based on analysis of wild populations of N. crassa and N. discreta, rcd-1 alleles appeared to be under balancing selection and associated with trans-species polymorphisms. We shed light on genomic rearrangements that could have led to the emergence of the incompatibility system in Neurospora and show that rcd-1 belongs to a much larger gene family in fungi. Overall, our work contributes toward a better understanding of allorecognition and PCD in an underexplored developmental stage of filamentous fungi.
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Affiliation(s)
- Asen Daskalov
- Plant and Microbial Biology Department, The University of California, Berkeley, California 94720
| | - Pierre Gladieux
- UMR BGPI, INRA, CIRAD, Montpellier SupAgro, University Montpellier, 34060, France
| | - Jens Heller
- Plant and Microbial Biology Department, The University of California, Berkeley, California 94720
- Environmental Genomics and Systems Biology Division, The Lawrence Berkeley National Laboratory, California 94720
| | - N Louise Glass
- Plant and Microbial Biology Department, The University of California, Berkeley, California 94720
- Environmental Genomics and Systems Biology Division, The Lawrence Berkeley National Laboratory, California 94720
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8
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The mitochondrial translocase of the inner membrane PaTim54 is involved in defense response and longevity in Podospora anserina. Fungal Genet Biol 2019; 132:103257. [PMID: 31351193 DOI: 10.1016/j.fgb.2019.103257] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 06/26/2019] [Accepted: 07/22/2019] [Indexed: 11/20/2022]
Abstract
Fungi are very successful microorganisms capable of colonizing virtually any ecological niche where they must constantly cope with competitors including fungi, bacteria and nematodes. We have shown previously that the ascomycete Podopora anserina exhibits Hyphal Interference (HI), an antagonistic response triggered by direct contact of competing fungal hyphae. When challenged with Penicillium chrysogenum, P. anserina produces hydrogen peroxide at the confrontation and kills the hyphae of P. chrysogenum. Here, we report the characterization of the PDC2218 mutant affected in HI. When challenged with P. chrysogenum, the PDC2218 mutant produces a massive oxidative burst at the confrontation. However, this increased production of hydrogen peroxide is not correlated to increased cell death in P. chrysogenum. Hence, the oxidative burst and cell death in the challenger are uncoupled in PDC2218. The gene affected in PDC2218 is PaTim54, encoding the homologue of the budding yeast mitochondrial inner membrane import machinery component Tim54p. We show that PaTim54 is essential in P. anserina and that the phenotypes displayed by the PDC2218 mutant, renamed PaTim542218, are the consequence of a drastic reduction in the expression of PaTim54. Among these pleiotropic phenotypes, PDC2218-PaTim542218- displays increased lifespan, a phenotype in line with the observed mitochondrial defects in the mutant.
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Bailey BA, Evans HC, Phillips‐Mora W, Ali SS, Meinhardt LW. Moniliophthora roreri, causal agent of cacao frosty pod rot. MOLECULAR PLANT PATHOLOGY 2018; 19:1580-1594. [PMID: 29194910 PMCID: PMC6638017 DOI: 10.1111/mpp.12648] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 11/27/2017] [Accepted: 11/28/2017] [Indexed: 06/07/2023]
Abstract
Taxonomy: Moniliophthora roreri (Cif.) H.C. Evans et al. ; Phylum Basidiomycota; Class Agaricomycetes; Order Agaricales; Family Marasmiaceae; Genus Moniliophthora. Biology: Moniliophthora roreri attacks Theobroma and Herrania species causing frosty pod rot. Theobroma cacao (cacao) is the host of major economic concern. Moniliophthora roreri is a hemibiotroph with a long biotrophic phase (45-90 days). Spore masses, of apparent asexual origin, are produced on the pod surface after initiation of the necrotrophic phase. Spores are spread by wind, rain and human activity. Symptoms of the biotrophic phase can include necrotic flecks and, in some cases, pod malformation, but pods otherwise remain asymptomatic. Relationship to Moniliophthora perniciosa: Moniliophthora roreri and Moniliophthora perniciosa, causal agent of witches' broom disease of cacao, are closely related. Their genomes are similar, including many of the genes they carry which are considered to be important in the disease process. Moniliophthora perniciosa, also a hemibiotroph, has a typical basidiomycete lifestyle and morphology, forming clamp connections and producing mushrooms. Basidiospores infect meristematic tissues including flower cushions, stem tips and pods. Moniliophthora roreri does not form clamp connections or mushrooms and infects pods only. Both pathogens are limited to the Western Hemisphere and are a threat to cacao production around the world. Agronomic importance: Disease losses caused by frosty pod rot can reach 90% and result in field abandonment. Moniliophthora roreri remains in the invasive phase in the Western Hemisphere, not having reached Brazil, some islands within the Caribbean and a few specific regions within otherwise invaded countries. DISEASE MANAGEMENT The disease can be managed by a combination of cultural (for example, maintenance of tree height and removal of infected pods) and chemical methods. These methods benefit from regional application, but can be cost prohibitive. Breeding for disease resistance offers the greatest potential for frosty pod rot management and new tolerant materials are becoming available.
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Affiliation(s)
- Bryan A. Bailey
- Sustainable Perennial Crops Laboratory, United States Department of AgricultureAgricultural Research ServiceBeltsvilleMD 20705USA
| | | | - Wilbert Phillips‐Mora
- Tropical Agricultural Research and Higher Education Center (CATIE)Turrialba 7170Costa Rica
| | - Shahin S. Ali
- Sustainable Perennial Crops Laboratory, United States Department of AgricultureAgricultural Research ServiceBeltsvilleMD 20705USA
| | - Lyndel W. Meinhardt
- Sustainable Perennial Crops Laboratory, United States Department of AgricultureAgricultural Research ServiceBeltsvilleMD 20705USA
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Toh YF, Yew SM, Chan CL, Na SL, Lee KW, Hoh CC, Yee WY, Ng KP, Kuan CS. Genome Anatomy of Pyrenochaeta unguis-hominis UM 256, a Multidrug Resistant Strain Isolated from Skin Scraping. PLoS One 2016; 11:e0162095. [PMID: 27626635 PMCID: PMC5023194 DOI: 10.1371/journal.pone.0162095] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 08/17/2016] [Indexed: 11/18/2022] Open
Abstract
Pyrenochaeta unguis-hominis is a rare human pathogen that causes infection in human skin and nail. P. unguis-hominis has received little attention, and thus, the basic biology and pathogenicity of this fungus is not fully understood. In this study, we performed in-depth analysis of the P. unguis-hominis UM 256 genome that was isolated from the skin scraping of a dermatitis patient. The isolate was identified to species level using a comprehensive multilocus phylogenetic analysis of the genus Pyrenochaeta. The assembled UM 256 genome has a size of 35.5 Mb and encodes 12,545 putative genes, and 0.34% of the assembled genome is predicted transposable elements. Its genomic features propose that the fungus is a heterothallic fungus that encodes a wide array of plant cell wall degrading enzymes, peptidases, and secondary metabolite biosynthetic enzymes. Antifungal drug resistance genes including MDR, CDR, and ERG11/CYP51 were identified in P. unguis-hominis UM 256, which may confer resistance to this fungus. The genome analysis of P. unguis-hominis provides an insight into molecular and genetic basis of the fungal lifestyles, understanding the unrevealed biology of antifungal resistance in this fungus.
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Affiliation(s)
- Yue Fen Toh
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Su Mei Yew
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Chai Ling Chan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Shiang Ling Na
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Kok Wei Lee
- Codon Genomics SB, Seri Kembangan, Selangor Darul Ehsan, Malaysia
| | - Chee-Choong Hoh
- Codon Genomics SB, Seri Kembangan, Selangor Darul Ehsan, Malaysia
| | - Wai-Yan Yee
- Codon Genomics SB, Seri Kembangan, Selangor Darul Ehsan, Malaysia
| | - Kee Peng Ng
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Chee Sian Kuan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
- * E-mail:
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11
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Comeau AM, Dufour J, Bouvet GF, Jacobi V, Nigg M, Henrissat B, Laroche J, Levesque RC, Bernier L. Functional annotation of the Ophiostoma novo-ulmi genome: insights into the phytopathogenicity of the fungal agent of Dutch elm disease. Genome Biol Evol 2014; 7:410-30. [PMID: 25539722 PMCID: PMC4350166 DOI: 10.1093/gbe/evu281] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/09/2014] [Indexed: 12/18/2022] Open
Abstract
The ascomycete fungus Ophiostoma novo-ulmi is responsible for the pandemic of Dutch elm disease that has been ravaging Europe and North America for 50 years. We proceeded to annotate the genome of the O. novo-ulmi strain H327 that was sequenced in 2012. The 31.784-Mb nuclear genome (50.1% GC) is organized into 8 chromosomes containing a total of 8,640 protein-coding genes that we validated with RNA sequencing analysis. Approximately 53% of these genes have their closest match to Grosmannia clavigera kw1407, followed by 36% in other close Sordariomycetes, 5% in other Pezizomycotina, and surprisingly few (5%) orphans. A relatively small portion (∼3.4%) of the genome is occupied by repeat sequences; however, the mechanism of repeat-induced point mutation appears active in this genome. Approximately 76% of the proteins could be assigned functions using Gene Ontology analysis; we identified 311 carbohydrate-active enzymes, 48 cytochrome P450s, and 1,731 proteins potentially involved in pathogen-host interaction, along with 7 clusters of fungal secondary metabolites. Complementary mating-type locus sequencing, mating tests, and culturing in the presence of elm terpenes were conducted. Our analysis identified a specific genetic arsenal impacting the sexual and vegetative growth, phytopathogenicity, and signaling/plant-defense-degradation relationship between O. novo-ulmi and its elm host and insect vectors.
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Affiliation(s)
- André M Comeau
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Québec, Canada Centre d'Étude de la Forêt (CEF), Université Laval, Québec, Québec, Canada Present address: Department of Pharmacology, Dalhousie University, Halifax, NS, Canada
| | - Josée Dufour
- Centre d'Étude de la Forêt (CEF), Université Laval, Québec, Québec, Canada
| | - Guillaume F Bouvet
- Institut de Recherches Cliniques de Montréal (IRCM), Montréal, Québec, Canada
| | - Volker Jacobi
- Centre d'Étude de la Forêt (CEF), Université Laval, Québec, Québec, Canada
| | - Martha Nigg
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Québec, Canada Centre d'Étude de la Forêt (CEF), Université Laval, Québec, Québec, Canada
| | - Bernard Henrissat
- Centre National de la Recherche Scientifique (CNRS), UMR7257, Université Aix-Marseille, France Department of Biological Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Jérôme Laroche
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Québec, Canada
| | - Roger C Levesque
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Québec, Canada Département de Microbiologie-Infectiologie et Immunologie, Faculté de Médecine, Université Laval, Québec, Québec, Canada
| | - Louis Bernier
- Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Québec, Canada Centre d'Étude de la Forêt (CEF), Université Laval, Québec, Québec, Canada
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12
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Czárán T, Hoekstra RF, Aanen DK. Selection against somatic parasitism can maintain allorecognition in fungi. Fungal Genet Biol 2014; 73:128-37. [PMID: 25305337 DOI: 10.1016/j.fgb.2014.09.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 09/25/2014] [Accepted: 09/29/2014] [Indexed: 01/12/2023]
Abstract
Fusion between multicellular individuals is possible in many organisms with modular, indeterminate growth, such as marine invertebrates and fungi. Although fusion may provide various benefits, fusion usually is restricted to close relatives by allorecognition, also called heterokaryon or somatic incompatibility in fungi. A possible selective explanation for allorecognition is protection against somatic parasites. Such mutants contribute less to colony functions but more to reproduction. However, previous models testing this idea have failed to explain the high diversity of allorecognition alleles in nature. These models did not, however, consider the possible role of spatial structure. We model the joint evolution of allorecognition and somatic parasitism in a multicellular organism resembling an asexual ascomycete fungus in a spatially explicit simulation. In a 1000-by-1000 grid, neighbouring individuals can fuse, but only if they have the same allotype. Fusion with a parasitic individual decreases the total reproductive output of the fused individuals, but the parasite compensates for this individual-level fitness reduction by a disproportional share of the offspring. Allorecognition prevents the invasion of somatic parasites, and vice versa, mutation towards somatic parasitism provides the selective conditions for extensive allorecognition diversity. On the one hand, if allorecognition diversity did not build up fast enough, somatic parasites went to fixation; conversely, once parasites had gone to fixation no allorecognition diversity built up. On the other hand, the mere threat of parasitism could select for high allorecognition diversity, preventing invasion of somatic parasites. Moderate population viscosity combined with weak global dispersal was optimal for the joint evolution of allorecognition and protection against parasitism. Our results are consistent with the widespread occurrence of allorecognition in fungi and the low degree of somatic parasitism. We discuss the implications of our results for allorecognition in other organism groups.
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Affiliation(s)
- Tamas Czárán
- MTA-ELTE Research Group of Theoretical Biology and Evolutionary Ecology, Pázmány Péter sétány 1/C, 1117 Budapest, Hungary.
| | - Rolf F Hoekstra
- Laboratory of Genetics, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands.
| | - Duur K Aanen
- Laboratory of Genetics, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands.
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13
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Abstract
Alcoholic fermentations have accompanied human civilizations throughout our history. Lager yeasts have a several-century-long tradition of providing fresh beer with clean taste. The yeast strains used for lager beer fermentation have long been recognized as hybrids between two Saccharomyces species. We summarize the initial findings on this hybrid nature, the genomics/transcriptomics of lager yeasts, and established targets of strain improvements. Next-generation sequencing has provided fast access to yeast genomes. Its use in population genomics has uncovered many more hybridization events within Saccharomyces species, so that lager yeast hybrids are no longer the exception from the rule. These findings have led us to propose network evolution within Saccharomyces species. This "web of life" recognizes the ability of closely related species to exchange DNA and thus drain from a combined gene pool rather than be limited to a gene pool restricted by speciation. Within the domesticated lager yeasts, two groups, the Saaz and Frohberg groups, can be distinguished based on fermentation characteristics. Recent evidence suggests that these groups share an evolutionary history. We thus propose to refer to the Saaz group as Saccharomyces carlsbergensis and to the Frohberg group as Saccharomyces pastorianus based on their distinct genomes. New insight into the hybrid nature of lager yeast will provide novel directions for future strain improvement.
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Xiong D, Wang Y, Ma J, Klosterman SJ, Xiao S, Tian C. Deep mRNA sequencing reveals stage-specific transcriptome alterations during microsclerotia development in the smoke tree vascular wilt pathogen, Verticillium dahliae. BMC Genomics 2014; 15:324. [PMID: 24884698 PMCID: PMC4035056 DOI: 10.1186/1471-2164-15-324] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 04/22/2014] [Indexed: 11/16/2022] Open
Abstract
Background Verticillium dahliae is a soil-borne fungus that causes vascular wilt diseases in a wide range of plant hosts. V. dahliae produces multicelled, melanized resting bodies, also known as microsclerotia (MS) that can survive for years in the soil. The MS are the primary source of infection of the Verticillium disease cycle. Thus, MS formation marks an important event in the disease cycle of V. dahliae. Results In this study, next generation sequencing technology of RNA-Seq was employed to investigate the global transcriptomic dynamics of MS development to identify differential gene expression at several stages of MS formation in strain XS11 of V. dahliae, isolated from smoke tree. We observed large-scale changes in gene expression during MS formation, such as increased expression of genes involved in protein metabolism and carbohydrate metabolism. Genes involved in glycolytic pathway and melanin biosynthesis were dramatically up-regulated in MS. Cluster analyses revealed increased expression of genes encoding products involved in primary metabolism and stress responses throughout MS development. Differential expression of ubiquitin-dependent protein catabolism and cell death-associated genes during MS development were revealed. Homologs of genes located in the lineage-specific (LS) regions of V. dahliae strain VdLs.17, were either not expressed or showed low expression. Furthermore, alternative splicing (AS) events were analyzed, revealing that over 95.0% AS events involve retention of introns (RI). Conclusions These data reveal the dynamics of transcriptional regulation during MS formation and were used to construct a comprehensive high-resolution gene expression map. This map provides a key resource for understanding the biology and molecular basis of MS development of V. dahliae. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-324) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | - Chengming Tian
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China.
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15
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Wang YY, Liu B, Zhang XY, Zhou QM, Zhang T, Li H, Yu YF, Zhang XL, Hao XY, Wang M, Wang L, Wei JC. Genome characteristics reveal the impact of lichenization on lichen-forming fungus Endocarpon pusillum Hedwig (Verrucariales, Ascomycota). BMC Genomics 2014; 15:34. [PMID: 24438332 PMCID: PMC3897900 DOI: 10.1186/1471-2164-15-34] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 01/14/2014] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Lichen is a classic mutualistic organism and the lichenization is one of the fungal symbioses. The lichen-forming fungus Endocarpon pusillum is living in symbiosis with the green alga Diplosphaera chodatii Bialsuknia as a lichen in the arid regions. RESULTS 454 and Illumina technologies were used to sequence the genome of E. pusillum. A total of 9,285 genes were annotated in the 37.5 Mb genome of E. pusillum. Analyses of the genes provided direct molecular evidence for certain natural characteristics, such as homothallic reproduction and drought-tolerance. Comparative genomics analysis indicated that the expansion and contraction of some protein families in the E. pusillum genome reflect the specific relationship with its photosynthetic partner (D. chodatii). Co-culture experiments using the lichen-forming fungus E. pusillum and its algal partner allowed the functional identification of genes involved in the nitrogen and carbon transfer between both symbionts, and three lectins without signal peptide domains were found to be essential for the symbiotic recognition in the lichen; interestingly, the ratio of the biomass of both lichen-forming fungus and its photosynthetic partner and their contact time were found to be important for the interaction between these two symbionts. CONCLUSIONS The present study lays a genomic analysis of the lichen-forming fungus E. pusillum for demonstrating its general biological features and the traits of the interaction between this fungus and its photosynthetic partner D. chodatii, and will provide research basis for investigating the nature of its drought resistance and symbiosis.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Lei Wang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
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16
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Shlezinger N, Goldfinger N, Sharon A. Apoptotic-like programed cell death in fungi: the benefits in filamentous species. Front Oncol 2012; 2:97. [PMID: 22891165 PMCID: PMC3412994 DOI: 10.3389/fonc.2012.00097] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2012] [Accepted: 07/23/2012] [Indexed: 11/13/2022] Open
Abstract
Studies conducted in the early 1990s showed for the first time that Saccharomyces cerevisiae can undergo cell death with hallmarks of animal apoptosis. These findings came as a surprise, since suicide machinery was unexpected in unicellular organisms. Today, apoptosis in yeast is well-documented. Apoptotic death of yeast cells has been described under various conditions and S. cerevisiae homologs of human apoptotic genes have been identified and characterized. These studies also revealed fundamental differences between yeast and animal apoptosis; in S. cerevisiae apoptosis is mainly associated with aging and stress adaptation, unlike animal apoptosis, which is essential for proper development. Further, many apoptosis regulatory genes are either missing, or highly divergent in S. cerevisiae. Therefore, in this review we will use the term apoptosis-like programed cell death (PCD) instead of apoptosis. Despite these significant differences, S. cerevisiae has been instrumental in promoting the study of heterologous apoptotic proteins, particularly from human. Work in fungi other than S. cerevisiae revealed differences in the manifestation of PCD in single cell (yeasts) and multicellular (filamentous) species. Such differences may reflect the higher complexity level of filamentous species, and hence the involvement of PCD in a wider range of processes and life styles. It is also expected that differences might be found in the apoptosis apparatus of yeast and filamentous species. In this review we focus on aspects of PCD that are unique or can be better studied in filamentous species. We will highlight the similarities and differences of the PCD machinery between yeast and filamentous species and show the value of using S. cerevisiae along with filamentous species to study apoptosis.
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Affiliation(s)
- Neta Shlezinger
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University,Tel Aviv, Israel
| | - Nir Goldfinger
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University,Tel Aviv, Israel
| | - Amir Sharon
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University,Tel Aviv, Israel
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Scheckhuber CQ, Hamann A, Brust D, Osiewacz HD. Cellular homeostasis in fungi: impact on the aging process. Subcell Biochem 2012; 57:233-250. [PMID: 22094425 DOI: 10.1007/978-94-007-2561-4_11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Cellular quality control pathways are needed for maintaining the biological function of organisms. If these pathways become compromised, the results are usually highly detrimental. Functional impairments of cell components can lead to diseases and in extreme cases to organismal death. Dysfunction of cells can be induced by a number of toxic by-products that are formed during metabolic activity, like reactive oxygen and nitrogen species, for example. A key source of reactive oxygen species (ROS) are the organelles of oxidative phosphorylation, mitochondria. Therefore mitochondrial function is also directly affected by ROS, especially if there is a compromised ROS-scavenging capacity. Biological systems therefore depend on several lines of defence to counteract the toxic effects of ROS and other damaging agents. The first level is active at the molecular level and consists of various proteases that bind and degrade abnormally modified and / or aggregated mitochondrial proteins. The second level is concerned with maintaining the quality of whole mitochondria. Among the pathways of this level are mitochondrial dynamics and autophagy (mitophagy). Mitochondrial dynamics describes the time-dependent fusion and fission of mitochondria. It is argued that this kind of organellar dynamics has the power to restore the function of impaired organelles by content mixing with intact organelles. If the first and second lines of defence against damage fail and mitochondria become damaged too severely, there is the option to remove affected cells before they can elicit more damage to their surrounding environment by apoptosis. This form of programmed cell death is strictly regulated by a complex network of interacting components and can be divided into mitochondria-dependent and mitochondria-independent modes of action. In this review we give an overview on various biological quality control systems in fungi (yeasts and filamentous fungi) with an emphasis on autophagy (mitophagy) and apoptosis and how these pathways allow fungal organisms to maintain a balanced cellular homeostasis.
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Affiliation(s)
- Christian Q Scheckhuber
- Faculty of Biosciences, Institute of Molecular Biosciences and Cluster of Excellence Macromolecular Complexes, Johann Wolfgang Goethe University, 60438, Frankfurt/Main, Germany,
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18
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Localization of HET-S to the cell periphery, not to [Het-s] aggregates, is associated with [Het-s]-HET-S toxicity. Mol Cell Biol 2011; 32:139-53. [PMID: 22037764 DOI: 10.1128/mcb.06125-11] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Prion diseases are associated with accumulation of the amyloid form of the prion protein, but the mechanisms of toxicity are unknown. Amyloid toxicity is also associated with fungal prions. In Podospora anserina, the simultaneous presence of [Het-s] prion and its allelic protein HET-S causes cell death in a self-/nonself-discrimination process. Here, using the prion form of a fragment of HET-s ([PrD(157)(+)]), we show that [Het-s]-HET-S toxicity can be faithfully recapitulated in yeast. Overexpression of Hsp40 chaperone, Sis1, rescues this toxicity by curing cells of [PrD(157)(+)]. We find no evidence for toxic [PrD(157)(+)] conformers in the presence of HET-S. Instead, [PrD(157)(+)] appears to seed HET-S to accumulate at the cell periphery and to form aggregates distinct from visible [PrD(157)(+)] aggregates. Furthermore, HET-S mutants that cause HET-S to be sequestered into [PrD(157)(+)] prion aggregates are not toxic. The localization of HET-S at the cell periphery and its association with cell death was also observed in the native host Podospora anserina. Thus, upon interaction with [Het-s], HET-S localizes to the cell periphery, and this relocalization, rather than the formation of mixed HET-s/HET-S aggregates, is associated with toxicity.
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19
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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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20
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Wickner RB, Edskes HK, Bateman D, Kelly AC, Gorkovskiy A. The yeast prions [PSI+] and [URE3] are molecular degenerative diseases. Prion 2011; 5:258-62. [PMID: 22052353 DOI: 10.4161/pri.17748] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The yeast prions [URE3] and [PSI] are not found in wild strains, suggesting they are not an advantage. Prion-forming ability is not conserved, even within Saccharomyces, suggesting it is a disease. Prion domains have non-prion functions, explaining some conservation of sequence. However, in spite of the sequence being constrained in evolution by these non-prion functions, the prion domains vary more rapidly than the remainder of the molecule, and these changes produce a transmission barrier, suggesting that these changes were selected to block prion infection. Yeast prions [PSI] and [URE3] induce a cellular stress response (Hsp104 and Hsp70 induction), suggesting the cells are not happy about being infected. Recently, we showed that the array of [PSI] and [URE3] prions includes a majority of lethal or very toxic variants, a result not expected if either prion were an adaptive cellular response to stress.
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Affiliation(s)
- Reed B Wickner
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Disease, National Institutes of Health, Bethesda, MD, USA.
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21
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Wickner RB, Edskes HK, Bateman D, Kelly AC, Gorkovskiy A. The yeast prions [PSI+] and [URE3] are molecular degenerative diseases. Prion 2011. [PMID: 22052353 DOI: 10.4161/pri.5.4.17748] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The yeast prions [URE3] and [PSI] are not found in wild strains, suggesting they are not an advantage. Prion-forming ability is not conserved, even within Saccharomyces, suggesting it is a disease. Prion domains have non-prion functions, explaining some conservation of sequence. However, in spite of the sequence being constrained in evolution by these non-prion functions, the prion domains vary more rapidly than the remainder of the molecule, and these changes produce a transmission barrier, suggesting that these changes were selected to block prion infection. Yeast prions [PSI] and [URE3] induce a cellular stress response (Hsp104 and Hsp70 induction), suggesting the cells are not happy about being infected. Recently, we showed that the array of [PSI] and [URE3] prions includes a majority of lethal or very toxic variants, a result not expected if either prion were an adaptive cellular response to stress.
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Affiliation(s)
- Reed B Wickner
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Disease, National Institutes of Health, Bethesda, MD, USA.
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22
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Purin S, Morton JB. In situ analysis of anastomosis in representative genera of arbuscular mycorrhizal fungi. MYCORRHIZA 2011; 21:505-514. [PMID: 21221661 DOI: 10.1007/s00572-010-0356-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Accepted: 12/20/2010] [Indexed: 05/30/2023]
Abstract
Arbuscular mycorrhizal fungi (AMF) form obligate symbiotic associations with plants. As a result, the role of hyphal interactions in the establishment and maintenance of common mycorrhizal networks is poorly understood because of constraints on methods for in situ analysis. We designed a rhizohyphatron that allows the examination of intact mycelia growing from whole mycorrhizal plants. Plants preinoculated with spores were cultivated in a compartment with a connecting tube from which hyphae extend through a fine nylon mesh onto agar-coated slides. Species selected from each of the five AMF genera were used to assess and characterize the anastomosis behavior in the rhizohyphatron. Hyphal networks of Paraglomus occultum, Ambispora leptoticha, Scutellospora heterogama, and Gigaspora gigantea growing on the agar-coated slides showed no evidence of hyphal fusion. In contrast, anastomosis occurred in the hyphal networks of Glomus clarum and Glomus intraradices at an average frequency of less than 15% for both species. The rhizohyphatron developed in this study will provide knowledge of the biology and genetics of self/non-self recognition in AMF and help to better understand Glomeromycotan life history strategies.
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Affiliation(s)
- Sonia Purin
- West Virginia University, 1090 Agricultural Sciences Building, Morgantown, WV, 26506, USA.
| | - Joseph B Morton
- West Virginia University, 1090 Agricultural Sciences Building, Morgantown, WV, 26506, USA
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Bartoszewska M, Kiel JAKW. The role of macroautophagy in development of filamentous fungi. Antioxid Redox Signal 2011; 14:2271-87. [PMID: 20712412 DOI: 10.1089/ars.2010.3528] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Autophagy (macroautophagy) is a bulk degradative pathway by which cytoplasmic components are delivered to the vacuole for recycling. This process is conserved from yeast to human, where it is implicated in cancer and neurodegenerative diseases. During the last decade, many ATG genes involved in autophagy have been identified, initially in Saccharomyces cerevisiae. This review summarizes the knowledge on the molecular mechanisms of autophagy using yeast as model system. Although many of the core components involved in autophagy are conserved from yeast to human, there are, nevertheless, significant differences between these organisms, for example, during autophagy initiation. Autophagy also plays an essential role in filamentous fungi especially during differentiation. Remarkably, in these species autophagy may reflect features of both yeast and mammals. This is exemplified by the finding that filamentous fungi lack the S. cerevisiae clade-specific Atg31 protein, but contain Atg101, which is absent in this clade. A reappraisal of genome data further suggests that, similar to yeast and mammals, filamentous fungi probably also contain two distinct phosphatidylinositol 3-kinase complexes. This review also summarizes the state of knowledge on the role of autophagy in filamentous fungi during differentiation, such as pathogenic development, programmed cell death during heteroincompatibility, and spore formation.
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Affiliation(s)
- Magdalena Bartoszewska
- Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Haren, The Netherlands
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24
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Architecture and development of the Neurospora crassa hypha – a model cell for polarized growth. Fungal Biol 2011; 115:446-74. [PMID: 21640311 DOI: 10.1016/j.funbio.2011.02.008] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Revised: 02/08/2011] [Accepted: 02/09/2011] [Indexed: 11/20/2022]
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Wickner RB, Shewmaker F, Edskes H, Kryndushkin D, Nemecek J, McGlinchey R, Bateman D, Winchester CL. Prion amyloid structure explains templating: how proteins can be genes. FEMS Yeast Res 2011; 10:980-91. [PMID: 20726897 DOI: 10.1111/j.1567-1364.2010.00666.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The yeast and fungal prions determine heritable and infectious traits, and are thus genes composed of protein. Most prions are inactive forms of a normal protein as it forms a self-propagating filamentous β-sheet-rich polymer structure called amyloid. Remarkably, a single prion protein sequence can form two or more faithfully inherited prion variants, in effect alleles of these genes. What protein structure explains this protein-based inheritance? Using solid-state nuclear magnetic resonance, we showed that the infectious amyloids of the prion domains of Ure2p, Sup35p and Rnq1p have an in-register parallel architecture. This structure explains how the amyloid filament ends can template the structure of a new protein as it joins the filament. The yeast prions [PSI(+)] and [URE3] are not found in wild strains, indicating that they are a disadvantage to the cell. Moreover, the prion domains of Ure2p and Sup35p have functions unrelated to prion formation, indicating that these domains are not present for the purpose of forming prions. Indeed, prion-forming ability is not conserved, even within Saccharomyces cerevisiae, suggesting that the rare formation of prions is a disease. The prion domain sequences generally vary more rapidly in evolution than does the remainder of the molecule, producing a barrier to prion transmission, perhaps selected in evolution by this protection.
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Affiliation(s)
- Reed B Wickner
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA.
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López‐Villavicencio M, Courjol F, Gibson AK, Hood ME, Jonot O, Shykoff JA, Giraud T. COMPETITION, COOPERATION AMONG KIN, AND VIRULENCE IN MULTIPLE INFECTIONS. Evolution 2010; 65:1357-66. [DOI: 10.1111/j.1558-5646.2010.01207.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Manuela López‐Villavicencio
- Origine, Structure, Evolution de la Diversité, UMR 7205 CNRS‐MNHN, Muséum national d’histoire naturelle, CP39, 57 rue Cuvier, 75231 Paris Cedex 05, France
- E‐mail:
| | - Flavie Courjol
- Ecologie, Systématique et Evolution, UMR 8079, Bâtiment 360, Université Paris‐Sud, F‐91405 Orsay cedex, France; UMR 8079, Bâtiment 360, CNRS, F‐91405 Orsay cedex; France
- E‐mail:
| | - Amanda K. Gibson
- Ecologie, Systématique et Evolution, UMR 8079, Bâtiment 360, Université Paris‐Sud, F‐91405 Orsay cedex, France; UMR 8079, Bâtiment 360, CNRS, F‐91405 Orsay cedex; France
- E‐mail:
| | - Michael E. Hood
- Department of Biology, McGuire Life Sciences Building, Amherst College, Rts 9 and 116, Amherst, Massachusetts 01002‐5000
- E‐mail:
| | - Odile Jonot
- Ecologie, Systématique et Evolution, UMR 8079, Bâtiment 360, Université Paris‐Sud, F‐91405 Orsay cedex, France; UMR 8079, Bâtiment 360, CNRS, F‐91405 Orsay cedex; France
- E‐mail:
| | - Jacqui A. Shykoff
- Ecologie, Systématique et Evolution, UMR 8079, Bâtiment 360, Université Paris‐Sud, F‐91405 Orsay cedex, France; UMR 8079, Bâtiment 360, CNRS, F‐91405 Orsay cedex; France
- E‐mail:
| | - Tatiana Giraud
- Ecologie, Systématique et Evolution, UMR 8079, Bâtiment 360, Université Paris‐Sud, F‐91405 Orsay cedex, France; UMR 8079, Bâtiment 360, CNRS, F‐91405 Orsay cedex; France
- E‐mail:
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Chevanne D, Saupe SJ, Clavé C, Paoletti M. WD-repeat instability and diversification of the Podospora anserina hnwd non-self recognition gene family. BMC Evol Biol 2010; 10:134. [PMID: 20459612 PMCID: PMC2873952 DOI: 10.1186/1471-2148-10-134] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Accepted: 05/06/2010] [Indexed: 01/07/2023] Open
Abstract
Background Genes involved in non-self recognition and host defence are typically capable of rapid diversification and exploit specialized genetic mechanism to that end. Fungi display a non-self recognition phenomenon termed heterokaryon incompatibility that operates when cells of unlike genotype fuse and leads to the cell death of the fusion cell. In the fungus Podospora anserina, three genes controlling this allorecognition process het-d, het-e and het-r are paralogs belonging to the same hnwd gene family. HNWD proteins are STAND proteins (signal transduction NTPase with multiple domains) that display a WD-repeat domain controlling recognition specificity. Based on genomic sequence analysis of different P. anserina isolates, it was established that repeat regions of all members of the gene family are extremely polymorphic and undergoing concerted evolution arguing for frequent recombination within and between family members. Results Herein, we directly analyzed the genetic instability and diversification of this allorecognition gene family. We have constituted a collection of 143 spontaneous mutants of the het-R (HNWD2) and het-E (hnwd5) genes with altered recognition specificities. The vast majority of the mutants present rearrangements in the repeat arrays with deletions, duplications and other modifications as well as creation of novel repeat unit variants. Conclusions We investigate the extreme genetic instability of these genes and provide a direct illustration of the diversification strategy of this eukaryotic allorecognition gene family.
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Affiliation(s)
- Damien Chevanne
- Laboratoire de Génétique Moléculaire des Champignons, IBGC, UMR 5095 Université Victor Segalen Bordeaux 2, 1 rue Camille Saint-Saëns, Bordeaux Cedex, France
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Abstract
In fungi, cell fusion between genetically unlike individuals triggers a cell death reaction known as the incompatibility reaction. In Podospora anserina, the genes controlling this process belong to a gene family encoding STAND proteins with an N-terminal cell death effector domain, a central NACHT domain and a C-terminal WD-repeat domain. These incompatibility genes are extremely polymorphic, subject to positive Darwinian selection and display a remarkable genetic plasticity allowing for constant diversification of the WD-repeat domain responsible for recognition of non-self. Remarkably, the architecture of these proteins is related to pathogen-recognition receptors ensuring innate immunity in plants and animals. Here, we hypothesize that these P. anserina incompatibility genes could be components of a yet-unidentified innate immune system of fungi. As already proposed in the case of plant hybrid necrosis or graft rejection in mammals, incompatibility could be a by-product of pathogen-driven divergence in host defense genes.
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Affiliation(s)
- Mathieu Paoletti
- Laboratoire de Génétique Moléculaire des Champignons, Institut de Biochimie et de Génétique Cellulaires, UMR 5095 CNRS-Université de Bordeaux 2, 1 rue Camille St Saëns, 33077 Bordeaux Cedex, France
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Alberti S, Halfmann R, King O, Kapila A, Lindquist S. A systematic survey identifies prions and illuminates sequence features of prionogenic proteins. Cell 2009; 137:146-58. [PMID: 19345193 DOI: 10.1016/j.cell.2009.02.044] [Citation(s) in RCA: 774] [Impact Index Per Article: 51.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2008] [Revised: 02/09/2009] [Accepted: 02/25/2009] [Indexed: 02/01/2023]
Abstract
Prions are proteins that convert between structurally and functionally distinct states, one or more of which is transmissible. In yeast, this ability allows them to act as non-Mendelian elements of phenotypic inheritance. To further our understanding of prion biology, we conducted a bioinformatic proteome-wide survey for prionogenic proteins in S. cerevisiae, followed by experimental investigations of 100 prion candidates. We found an unexpected amino acid bias in aggregation-prone candidates and discovered that 19 of these could also form prions. At least one of these prion proteins, Mot3, produces a bona fide prion in its natural context that increases population-level phenotypic heterogeneity. The self-perpetuating states of these proteins present a vast source of heritable phenotypic variation that increases the adaptability of yeast populations to diverse environments.
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Affiliation(s)
- Simon Alberti
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
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Abstract
Autophagy has been monitored in the filamentous fungus Podospora anserina using electron, light, and fluorescence microscopy. In this organism autophagy can be induced either by starvation or rapamycin treatment or by het gene incompatibility. Incompatible HET products signal a cell death reaction referred to as cell death by incompatibility. In het-R het-V strain bearing the two incompatible het-R and het-V genes, cell death is induced by a simple shift in growth temperature, as incompatibility is thermosensitive. In this strain large autophagosomes are formed as revealed by electron microscopy or using the GFP-PaATG8 marker. This strain constitutes an alternative model to study autophagy. Analysis of the three autophagy mutants, DeltaPaATG1, DeltaPaATG8, and DeltapspA, reveals that autophagy is essential for aerial hyphae and female organ differentiation and involved in spore germination. During the incompatibility reaction, autophagy might protect cells from cell death as suggested by accelerated cell death observed in autophagy mutants.
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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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32
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Aanen DK, Debets AJM, de Visser JAGM, Hoekstra RF. The social evolution of somatic fusion. Bioessays 2008; 30:1193-203. [PMID: 18937373 DOI: 10.1002/bies.20840] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The widespread potential for somatic fusion among different conspecific multicellular individuals suggests that such fusion is adaptive. However, because recognition of non-kin (allorecognition) usually leads to a rejection response, successful somatic fusion is limited to close kin. This is consistent with kin-selection theory, which predicts that the potential cost of fusion and the potential for somatic parasitism decrease with increasing relatedness. Paradoxically, however, Crozier found that, in the short term, positive-frequency-dependent selection eliminates the required genetic polymorphism at allorecognition loci. The 'Crozier paradox' may be solved if allorecognition is based on extrinsically balanced polymorphisms, for example at immune loci. Alternatively, the assumption of most models that self fusion is mutually beneficial is wrong. If fusion is on average harmful, selection will promote unconditional rejection. However, we propose that fusion within individuals is beneficial, selecting for the ability to fuse, but fusion between individuals on average costly, selecting for non-self recognition (rather than non-kin recognition). We discuss experimental data on fungi that are consistent with this hypothesis.
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Affiliation(s)
- Duur K Aanen
- Plant Sciences, Laboratory of genetics, Wageningen University, Netherlands.
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Collado-Romero M, Mercado-Blanco J, Olivares-García C, Jiménez-Díaz RM. Phylogenetic analysis of Verticillium dahliae vegetative compatibility groups. PHYTOPATHOLOGY 2008; 98:1019-1028. [PMID: 18943740 DOI: 10.1094/phyto-98-9-1019] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The evolutionary relationships among Verticillium dahliae vegetative compatibility (VCG) subgroups VCG1A, VCG1B, VCG2A, VCG2B, VCG4A, VCG4B, and VCG6 were investigated by parsimony analysis of amplified fragment length polymorphism (AFLP) fingerprints and sequences of six DNA regions (actin, beta-tubulin, calmodulin, and histone 3 genes, the ITS 1 and 2 regions of the rDNA, and a V. dahliae-specific sequence), using 101 isolates of diverse host and geographic origin. Polymorphisms in gene sequences among isolates of different VCGs were very low and individual gene genealogies provided very little resolution at the VCG level. The combined analysis of all DNA regions differentiated all VCG subgroups except for isolates in VCG1A and VCG1B. VCG clonal lineages in V. dahliae and evolutionary relationships among them were resolved independently by analyses of AFLP fingerprints, multiple gene genealogies, and the combined data set of AFLP fingerprinting and multiple gene genealogies. Two main lineages (I and II) were identified with lineage II comprising two closely related subgroups of VCGs. Lineage I included VCG1A, VCG1B, and VCG2B334; and lineage II included, VCG2A and VCG4B (subclade 1); and VCG2B824, VCG4A, and VCG6 (subclade 2). VCG subgroups were monophyletic except for VCG2B that appeared polyphyletic. Limiting the parsimony analysis either to AFLP fingerprints or DNA sequences would have obscured intra-VCG differentiation. Therefore, the dual approach represented by the independent and combined analyses of AFLP fingerprints and DNA sequences was a highly valuable method for the identification of phylogenetic relationships at the intraspecific level in V. dahliae.
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Affiliation(s)
- M Collado-Romero
- Instituto de Agricultura Sostenible (IAS), Consejo Superior de Investigaciones Científicas (CSIC), Córdoba, Spain
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Crozet C, Lehmann S. [Prions: where do we stand 20 years after the appearance of bovine spongiform encephalopathy?]. Med Sci (Paris) 2007; 23:1148-57. [PMID: 18154718 DOI: 10.1051/medsci/200723121148] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Bovine spongiform encephalopathy (BSE) is a transmissible spongiform encephalopathy (TSE) identified twenty years ago in the British cattle herds. Creutzfeldt-Jakob disease (CJD) is a TSE that occurs in humans. In 1996, scientists found a possible link between BSE and a new variant of CJD (vCJD). The fact that the non conventional infectious agent of TSE, named prions, could cross the species barrier from cattle to human through meat consumption, raised a tremendous concern for public safety in Europe. This led to the development in the following two decades of substantial and expensive measures to contain BSE and prevent its transmission to humans. In parallel, scientific programs have been funded to progress through the comprehension of the physiopathology of these fatal disorders. In Europe, the BSE epidemics is now ending and the number of cases is decreasing thanks to the strict control of animal foodstuff that was the main source of prion contamination. Only a small number of vCJD have been detected, however, additional concerns have been raised recently for public safety as secondary transmission of CJD through medical procedure and blood transfusion is possible. In addition, the possibility that the BSE was transmitted to other animals including small ruminants is also worrisome. Research efforts are now focussing on decontamination and ante mortem diagnosis of TSE to prevent animal and human transmission. However, needs for fundamental research are still important as many questions remain to be addressed to understand the mechanism of prion transmission, as well as its pathogenesis.
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Affiliation(s)
- Carole Crozet
- Institut de Génétique Humaine, UPR1142 CNRS, CHU de Montpellier, UM1 Montpellier, 141, rue de la Cardonille, 34396 Montpellier Cedex 5, France
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35
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Paoletti M, Clavé C. The fungus-specific HET domain mediates programmed cell death in Podospora anserina. EUKARYOTIC CELL 2007; 6:2001-8. [PMID: 17873080 PMCID: PMC2168401 DOI: 10.1128/ec.00129-07] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Vegetative incompatibility is a programmed cell death reaction that occurs when fungal cells of unlike genotypes fuse. Genes defining vegetative incompatibility (het genes) are highly polymorphic, and most if not all incompatibility systems include a protein partner bearing the fungus-specific domain termed the HET domain. The nonallelic het-C/het-E incompatibility system is the best-characterized incompatibility system in Podospora anserina. Cell death is triggered by interaction of specific alleles of het-C, encoding a glycolipid transfer protein, and het-E, encoding a HET domain and a WD repeat domain involved in recognition. We show here that overexpression of the isolated HET domain from het-E results in cell death. This cell death is characterized by induction of autophagy, increased vacuolization, septation, and production of lipid droplets, which are hallmarks of cell death by incompatibility. In addition, the HET domain lethality is suppressed by the same mutations as vegetative incompatibility, but not by the inactivation of het-C. These results establish the HET domain as the mediator of cell death by incompatibility and lead to a modular conception of incompatibility systems whereby recognition is ensured by the variable regions of incompatibility proteins and cell death is triggered by the HET domain.
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Affiliation(s)
- M Paoletti
- Laboratoire de Génétique Moléculaire des Champignons, UMR-5095 CNRS et Université de Bordeaux 2, IBGC, 1 rue Camille Saint-Saëns, 33077 Bordeaux Cedex, France.
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Kerényi Z, Oláh B, Jeney A, Hornok L, Leslie JF. The homologue of het-c of Neurospora crassa lacks vegetative compatibility function in Fusarium proliferatum. Appl Environ Microbiol 2006; 72:6527-32. [PMID: 17021201 PMCID: PMC1610276 DOI: 10.1128/aem.01543-06] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
For two fungal strains to be vegetatively compatible and capable of forming a stable vegetative heterokaryon they must carry matching alleles at a series of loci variously termed het or vic genes. Cloned het/vic genes from Neurospora crassa and Podospora anserina have no obvious functional similarity and have various cellular functions. Our objective was to identify the homologue of the Neurospora het-c gene in Fusarium proliferatum and to determine if this gene has a vegetative compatibility function in this economically important and widely dispersed fungal pathogen. In F. proliferatum and five other closely related Fusarium species we found a few differences in the DNA sequence, but the changes were silent and did not alter the amino acid sequence of the resulting protein. Deleting the gene altered sexual fertility as the female parent, but it did not alter male fertility or existing vegetative compatibility interactions. Replacement of the allele-specific portion of the coding sequence with the sequence of an alternate allele in N. crassa did not result in a vegetative incompatibility response in transformed strains of F. proliferatum. Thus, the fphch gene in Fusarium appears unlikely to have the vegetative compatibility function associated with its homologue in N. crassa. These results suggest that the vegetative compatibility phenotype may result from convergent evolution. Thus, the genes involved in this process may need to be identified at the species level or at the level of a group of species and could prove to be attractive targets for the development of antifungal agents.
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Affiliation(s)
- Zoltán Kerényi
- Agricultural Biotechnology Center, Szent-Györgyi A u 4, H-2100 Gödöll, Hungary
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37
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Siemer AB, Arnold AA, Ritter C, Westfeld T, Ernst M, Riek R, Meier BH. Observation of Highly Flexible Residues in Amyloid Fibrils of the HET-s Prion. J Am Chem Soc 2006; 128:13224-8. [PMID: 17017802 DOI: 10.1021/ja063639x] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report the observation of undetected (until now) residues of the prion protein fragment HET-s(218-289) which give rise to well-resolved (13)C, (15)N, and (1)H NMR resonances under high-resolution magic-angle spinning (HRMAS) conditions. The observed signals belong to large polymeric units as shown by measuring the lateral diffusion constants. The amino acids identified in the spectra are compatible with their localization in the segments of the protein which could not be detected in earlier solid-state NMR experiments. The observed chemical shifts indicate that these residues are in a random-coil conformation. Complementary experiments which detect only dynamic or static residues, respectively, strongly suggest that they belong to different parts of the same molecule.
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38
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Robson GD. Programmed cell death in the aspergilli and other filamentous fungi. Med Mycol 2006; 44:S109-S114. [DOI: 10.1080/13693780600835765] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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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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Wickner RB, Edskes HK, Ross ED, Pierce MM, Shewmaker F, Baxa U, Brachmann A. Prions of yeast are genes made of protein: amyloids and enzymes. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2005; 69:489-96. [PMID: 16117685 DOI: 10.1101/sqb.2004.69.489] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- R B Wickner
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0830, USA
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Dalstra HJP, van der Zee R, Swart K, Hoekstra RF, Saupe SJ, Debets AJM. Non-mendelian inheritance of the HET-s prion or HET-s prion domains determines the het-S spore killing system in Podospora anserina. Fungal Genet Biol 2005; 42:836-47. [PMID: 16043372 DOI: 10.1016/j.fgb.2005.05.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2005] [Revised: 04/01/2005] [Accepted: 05/19/2005] [Indexed: 11/30/2022]
Abstract
Two alleles of the het-s/S locus occur naturally in the filamentous fungus Podospora anserina, het-s and het-S. The het-s encoded protein can form a prion that propagates a self-perpetuating amyloid aggregate, resulting in two phenotypes for the het-s strains. The prion-infected [Het-s] shows an antagonistic interaction to het-S whereas the prion-free [Het-s*] is neutral in interaction to het-S. The antagonism between [Het-s] and het-S is seen as heterokaryon incompatibility at the somatic level and as het-S spore killing in the sexual cycle. Two different domains of the HET-s and HET-S proteins have been identified, and a structure-function relationship has been established for interactions at the somatic level. In this study, we correlate accumulation of the HET-s and HET-S proteins (visualized using GFP) during the sexual cycle with timing of het-S spore abortion. Also, we present the structure-function relationship of the HET-s domains for interactions in the sexual cycle. We show that the constructs that ensure het-s incompatibility function in somatic mycelium are also active in het-S spore killing in the sexual cycle. In addition, paternal prion transmission and het-S spore killing has been found with the HET-s(157-289) truncated protein. The consequences of the unique transition from a coenocytic to a cellular state in the sexual phase and the timing, and localization of paternal and maternal HET-s and HET-S expression that are pertinent to prion transmission, and het-S spore killing are elaborated. These data further support our previously proposed model for het-S spore killing.
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Affiliation(s)
- Henk J P Dalstra
- Laboratory of Genetics, Wageningen University, Arboretumlaan 4, 6703 BD Wageningen, The Netherlands
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42
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Wickner RB, Edskes HK, Ross ED, Pierce MM, Baxa U, Brachmann A, Shewmaker F. Prion genetics: new rules for a new kind of gene. Annu Rev Genet 2005; 38:681-707. [PMID: 15355224 DOI: 10.1146/annurev.genet.38.072902.092200] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Just as nucleic acids can carry out enzymatic reactions, proteins can be genes. These heritable infectious proteins (prions) follow unique genetic rules that enable their identification: reversible curing, inducible "spontaneous generation," and phenotype surprises. Most prions are based on self-propagating amyloids, depend heavily on chaperones, show strain phenomena and, like other infectious elements, show species barriers to transmission. A recently identified prion is based on obligatory self-activation of an enzyme in trans. Although prions can be detrimental, they may also be beneficial to their hosts.
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Affiliation(s)
- Reed B Wickner
- Laboraory of Biochemistry and Genetics, National Institute of Diabetes Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0830, USA.
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43
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Xiang Q, Glass NL. Chromosome rearrangements in isolates that escape from het-c heterokaryon incompatibility in Neurospora crassa. Curr Genet 2003; 44:329-38. [PMID: 14564476 DOI: 10.1007/s00294-003-0451-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2003] [Revised: 08/29/2003] [Accepted: 09/08/2003] [Indexed: 10/26/2022]
Abstract
Chromosomal rearrangement is implicated in human cancers and hereditary diseases. Mechanisms generating chromosomal rearrangements may be shared by a variety of organisms. Spontaneous chromosomal rearrangements, especially large deletions, take place at high frequency in isolates that escape from heterokaryon incompatibility in Neurospora crassa. In this study, chromosomal rearrangements were detected in strains that had escaped from het-c heterokaryon incompatibility in N. crassa. A vc1 mutant carried a 20-kbp deletion covering five ORFs. A vc2 mutant carried a complex chromosome rearrangement with an 8-kbp deletion covering three ORFs, a 34-bp deletion and an 80-kbp inversion. The break-points of chromosome rearrangements in the vc1 and vc2 mutants all have direct repeats of 2 bp, similar to the break-points of some chromosome rearrangements associated with human cancer and genetic diseases. An ahc mutant carried a 31-kbp deletion covering at least 11 ORFs and a het-c deletion mutant carried a 7-kbp deletion covering two ORFs. Additional chromosomal rearrangements occurred in these two strains. These results indicate that escape from heterokaryon incompatibility can be used as a model system for chromosome rearrangement and DNA-repair studies. The impact of the chromosomal rearrangements is discussed, especially the deletion of the predicted ORFs on the phenotype of mutants.
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Affiliation(s)
- Qijun Xiang
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3102, USA
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44
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Dalstra HJP, Swart K, Debets AJM, Saupe SJ, Hoekstra RF. Sexual transmission of the [Het-S] prion leads to meiotic drive in Podospora anserina. Proc Natl Acad Sci U S A 2003; 100:6616-21. [PMID: 12719532 PMCID: PMC164496 DOI: 10.1073/pnas.1030058100] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2003] [Indexed: 11/18/2022] Open
Abstract
In the filamentous fungus Podospora anserina, two phenomena are associated with polymorphism at the het-s locus, vegetative incompatibility and ascospore abortion. Two het-s alleles occur naturally, het-s and het-S. The het-s encoded protein is a prion propagating as a self-perpetuating amyloid aggregate. When prion-infected [Het-s] hyphae fuse with [Het-S] hyphae, the resulting heterokaryotic cells necrotize. [Het-s] and [Het-S] strains are sexually compatible. When, however, a female [Het-s] crosses with [Het-S], a significant percentage of het-S spores abort, in a way similar to spore killing in Neurospora and Podospora. We report here that sexual transmission of the [Het-s] prion after nonisogamous mating in the reproductive cycle of Podospora is responsible for the killing of het-S spores. Progeny of crosses between isogenic strains with distinct wild-type or introduced, ectopic het-s/S alleles were cytologically and genetically analyzed. The effect of het-s/S overexpression, ectopic het-s/S expression, absence of het-s expression, loss of [Het-s] prion infection, and the distribution patterns of HET-s/S-GFP proteins were categorized during meiosis and ascospore formation. This study unveiled a het-S spore-killing system that is governed by dosage of and interaction between the [Het-s] prion and the HET-S protein. Due to this property of the [Het-s] prion, the het-s allele acts as a meiotic drive element favoring maintenance of the prion-forming allele in natural populations.
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Affiliation(s)
- Henk J P Dalstra
- Laboratory of Genetics, Wageningen University, Arboretumlaan 4, The Netherlands.
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Mattjus P, Turcq B, Pike HM, Molotkovsky JG, Brown RE. Glycolipid intermembrane transfer is accelerated by HET-C2, a filamentous fungus gene product involved in the cell-cell incompatibility response. Biochemistry 2003; 42:535-42. [PMID: 12525182 PMCID: PMC2593802 DOI: 10.1021/bi026896x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Among filamentous fungi capable of mycelial growth, het genes play crucial roles by regulating heterokaryon formation between different individuals. When fusion occurs between fungal mycelia that differ genetically at their het loci, the resulting heterokaryotic cells are quickly destroyed. It is unclear how het gene products of Podospora anserina trigger heterokaryon incompatibility. One unexplored possibility is that glycosphingolipids play a role because the het-c2 gene encodes a protein that displays 32% sequence identity and an additional 30% similarity to the mammalian glycolipid transfer protein. Here, P. anserina protoplasts containing wild-type het-c2 genes were shown to have greater glycosphingolipid transfer activity than protoplasts with disrupted het-c2 genes, a condition previously linked to altered cell compatibility following hyphal fusion. The observed glycolipid transfer activity could not be accounted for by nonspecific lipid transfer protein activity. Direct assessment showed that purified, recombinant HET-C2 accelerates the intermembrane transfer of glycolipid in vitro, but that the HET-C2 activity is mitigated much less by negatively charged membranes than the mammalian glycolipid transfer protein. The findings are discussed within the context of HET-C2 being a member of an emerging family of ancestral sphingolipid transfer proteins that play important roles in cell proliferation and accelerated death.
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Affiliation(s)
- Peter Mattjus
- The Hormel Institute, University of Minnesota, 801 16th Avenue NE Austin, Minnesota 55912, USA.
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Biella S, Smith ML, Aist JR, Cortesi P, Milgroom MG. Programmed cell death correlates with virus transmission in a filamentous fungus. Proc Biol Sci 2002; 269:2269-76. [PMID: 12455515 PMCID: PMC1691157 DOI: 10.1098/rspb.2002.2148] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Programmed cell death (PCD) is an essential part of the defence response in plants and animals against pathogens. Here, we report that PCD is also involved in defence against pathogens of fungi. Vegetative incompatibility is a self/non-self recognition system in fungi that results in PCD when cells of incompatible strains fuse. We quantified the frequency of cell death associated with six vegetative incompatibility (vic) genes in the filamentous ascomycete fungus Cryphonectria parasitica. Cell death frequencies were compared with the effects of vic genes on transmission of viruses between the same strains. We found a significant negative correlation between cell death and virus transmission. We also show that asymmetry in cell death correlates with asymmetry in virus transmission; greater transmission occurs into vic genotypes that exhibit delayed or infrequent PCD after fusion with an incompatible strain. Furthermore, we found that virus infection can have a significant, strain-specific, positive or negative effect on PCD. Specific interactions between vic gene function and viruses, along with correlations between cell death and transmission, strongly implicate PCD as a host-mediated pathogen defence strategy in fungi.
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Affiliation(s)
- Silvia Biella
- Department of Plant Pathology, Cornell University, Ithaca, NY 14853, USA
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Abstract
In this review, we give a summary of recent examples of hybridisation in fungi. Reports on hybridisation between pathogenic fungi infecting plants have increased during the last decade. Hybrids of plant pathogens may create devastating new diseases on both cultivated and wild plants; at the same time, hybridisation is one of the natural processes in the course of evolution of new taxa.
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Affiliation(s)
- Ake Olson
- Department of Forest Mycology and Pathology, Swedish University of Agricultural Sciences, Box 7026, 75007 Uppsala, Sweden.
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48
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Muirhead CA, Glass NL, Slatkin M. Multilocus self-recognition systems in fungi as a cause of trans-species polymorphism. Genetics 2002; 161:633-41. [PMID: 12072460 PMCID: PMC1462126 DOI: 10.1093/genetics/161.2.633] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Trans-species polymorphism, meaning the presence of alleles in different species that are more similar to each other than they are to alleles in the same species, has been found at loci associated with vegetative incompatibility in filamentous fungi. If individuals differ at one or more of these loci (termed het for heterokaryon), they cannot form stable heterokaryons after vegetative fusion. At the het-c locus in Neurospora crassa and related species there is clear evidence of trans-species polymorphism: three alleles have persisted for approximately 30 million years. We analyze a population genetic model of multilocus vegetative incompatibility and find the conditions under which trans-species polymorphism will occur. In the model, several unlinked loci determine the vegetative compatibility group (VCG) of an individual. Individuals of different VCGs fail to form productive heterokaryons, while those of the same VCG form viable heterokaryons. However, viable heterokaryon formation between individuals of the same VCG results in a loss in fitness, presumably via transfer of infectious agents by hyphal fusion or exploitation by aggressive genotypes. The result is a form of balancing selection on all loci affecting an individual's VCG. We analyze this model by making use of a Markov chain/strong selection, weak mutation (SSWM) approximation. We find that trans-species polymorphism of the type that has been found at the het-c locus is expected to occur only when the appearance of new incompatibility alleles is strongly constrained, because the rate of mutation to such alleles is very low, because the number of possible incompatibility alleles at each locus is restricted, or because the number of incompatibility loci is limited.
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Affiliation(s)
- Christina A Muirhead
- Department of Integrative Biology, University of California, Berkeley, California 94720-3140, USA
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Abstract
Infectious, self-propagating protein aggregates (prions) as well as structurally related amyloid fibrils have traditionally been associated with neurodegenerative diseases in mammals. However, recent work in fungi indicates that prions are not simply aberrations of protein folding, but are in fact widespread, conserved, and in certain cases, apparently beneficial. Analysis of prion behavior in yeast has led to insights into the mechanisms of prion appearance and propagation as well as the effect of prions on cellular physiology and perhaps evolution. The prion-forming proteins of Saccharomyces cerevisiae are members of a larger class of Gln/Asn-rich proteins that is abundantly represented in the genomes of higher eukaryotes, raising the prospect of genetically programmed prion-like behavior in other organisms.
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Affiliation(s)
- Lev Z Osherovich
- Howard Hughes Medical Institute, Department of Cellular, University of California, San Francisco 94143, USA.
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50
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Cortesi P, McCulloch CE, Song H, Lin H, Milgroom MG. Genetic control of horizontal virus transmission in the chestnut blight fungus, Cryphonectria parasitica. Genetics 2001; 159:107-18. [PMID: 11560890 PMCID: PMC1461798 DOI: 10.1093/genetics/159.1.107] [Citation(s) in RCA: 145] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Vegetative incompatibility in fungi has long been known to reduce the transmission of viruses between individuals, but the barrier to transmission is incomplete. In replicated laboratory assays, we showed conclusively that the transmission of viruses between individuals of the chestnut blight fungus Cryphonectria parasitica is controlled primarily by vegetative incompatibility (vic) genes. By replicating vic genotypes in independent fungal isolates, we quantified the effect of heteroallelism at each of six vic loci on virus transmission. Transmission occurs with 100% frequency when donor and recipient isolates have the same vic genotypes, but heteroallelism at one or more vic loci generally reduces virus transmission. Transmission was variable among single heteroallelic loci. At the extremes, heteroallelism at vic4 had no effect on virus transmission, but transmission occurred in only 21% of pairings that were heteroallelic at vic2. Intermediate frequencies of transmission were observed when vic3 and vic6 were heteroallelic (76 and 32%, respectively). When vic1, vic2, and vic7 were heteroallelic, the frequency of transmission depended on which alleles were present in the donor and the recipient. The effect of heteroallelism at two vic loci was mostly additive, although small but statistically significant interactions (epistasis) were observed in four pairs of vic loci. A logistic regression model was developed to predict the probability of virus transmission between vic genotypes. Heteroallelism at vic loci, asymmetry, and epistasis were the dominant factors controlling transmission, but host genetic background also was statistically significant, indicating that vic genes alone cannot explain all the variation in virus transmission. Predictions from the logistic regression model were highly correlated to independent transmission tests with field isolates. Our model can be used to estimate horizontal transmission rates as a function of host genetics in natural populations of C. parasitica.
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Affiliation(s)
- P Cortesi
- Istituto di Patologia Vegetale, Università degli Studi di Milano, 20133 Milan, Italy
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