1
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Chen H, King R, Smith D, Bayon C, Ashfield T, Torriani S, Kanyuka K, Hammond-Kosack K, Bieri S, Rudd J. Combined pangenomics and transcriptomics reveals core and redundant virulence processes in a rapidly evolving fungal plant pathogen. BMC Biol 2023; 21:24. [PMID: 36747219 PMCID: PMC9903594 DOI: 10.1186/s12915-023-01520-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 01/19/2023] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Studying genomic variation in rapidly evolving pathogens potentially enables identification of genes supporting their "core biology", being present, functional and expressed by all strains or "flexible biology", varying between strains. Genes supporting flexible biology may be considered to be "accessory", whilst the "core" gene set is likely to be important for common features of a pathogen species biology, including virulence on all host genotypes. The wheat-pathogenic fungus Zymoseptoria tritici represents one of the most rapidly evolving threats to global food security and was the focus of this study. RESULTS We constructed a pangenome of 18 European field isolates, with 12 also subjected to RNAseq transcription profiling during infection. Combining this data, we predicted a "core" gene set comprising 9807 sequences which were (1) present in all isolates, (2) lacking inactivating polymorphisms and (3) expressed by all isolates. A large accessory genome, consisting of 45% of the total genes, was also defined. We classified genetic and genomic polymorphism at both chromosomal and individual gene scales. Proteins required for essential functions including virulence had lower-than average sequence variability amongst core genes. Both core and accessory genomes encoded many small, secreted candidate effector proteins that likely interact with plant immunity. Viral vector-mediated transient in planta overexpression of 88 candidates failed to identify any which induced leaf necrosis characteristic of disease. However, functional complementation of a non-pathogenic deletion mutant lacking five core genes demonstrated that full virulence was restored by re-introduction of the single gene exhibiting least sequence polymorphism and highest expression. CONCLUSIONS These data support the combined use of pangenomics and transcriptomics for defining genes which represent core, and potentially exploitable, weaknesses in rapidly evolving pathogens.
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Affiliation(s)
- Hongxin Chen
- grid.418374.d0000 0001 2227 9389Department of Protecting Crops and the Environment, Rothamsted Research, Harpenden, Herts UK ,grid.12981.330000 0001 2360 039XPresent address: School of Agriculture, Shenzhen Campus of Sun Yat-sen University, Guangming District, Shenzhen, Guangdong People’s Republic of China
| | - Robert King
- grid.418374.d0000 0001 2227 9389Department of Protecting Crops and the Environment, Rothamsted Research, Harpenden, Herts UK
| | - Dan Smith
- grid.418374.d0000 0001 2227 9389Department of Protecting Crops and the Environment, Rothamsted Research, Harpenden, Herts UK
| | - Carlos Bayon
- grid.418374.d0000 0001 2227 9389Department of Protecting Crops and the Environment, Rothamsted Research, Harpenden, Herts UK
| | - Tom Ashfield
- grid.418374.d0000 0001 2227 9389Department of Protecting Crops and the Environment, Rothamsted Research, Harpenden, Herts UK ,grid.418374.d0000 0001 2227 9389Crop Health and Protection (CHaP), Rothamsted Research, Harpenden, Herts UK
| | - Stefano Torriani
- grid.420222.40000 0001 0669 0426Syngenta Crop Protection AG, Schaffhauserstrasse 101, CH-4332 Stein, Switzerland
| | - Kostya Kanyuka
- grid.418374.d0000 0001 2227 9389Department of Protecting Crops and the Environment, Rothamsted Research, Harpenden, Herts UK ,grid.17595.3f0000 0004 0383 6532Present address: National Institute for Agricultural Botany (NIAB), 93 Lawrence Weaver Road, Cambridge, UK
| | - Kim Hammond-Kosack
- grid.418374.d0000 0001 2227 9389Department of Protecting Crops and the Environment, Rothamsted Research, Harpenden, Herts UK
| | - Stephane Bieri
- grid.420222.40000 0001 0669 0426Syngenta Crop Protection AG, Schaffhauserstrasse 101, CH-4332 Stein, Switzerland
| | - Jason Rudd
- Department of Protecting Crops and the Environment, Rothamsted Research, Harpenden, Herts, UK.
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Blyth HR, Smith D, King R, Bayon C, Ashfield T, Walpole H, Venter E, Ray RV, Kanyuka K, Rudd JJ. Fungal plant pathogen "mutagenomics" reveals tagged and untagged mutations in Zymoseptoria tritici and identifies SSK2 as key morphogenesis and stress-responsive virulence factor. FRONTIERS IN PLANT SCIENCE 2023; 14:1140824. [PMID: 37206970 PMCID: PMC10190600 DOI: 10.3389/fpls.2023.1140824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 03/29/2023] [Indexed: 05/21/2023]
Abstract
"Mutagenomics" is the combination of random mutagenesis, phenotypic screening, and whole-genome re-sequencing to uncover all tagged and untagged mutations linked with phenotypic changes in an organism. In this study, we performed a mutagenomics screen on the wheat pathogenic fungus Zymoseptoria tritici for altered morphogenetic switching and stress sensitivity phenotypes using Agrobacterium-mediated "random" T-DNA mutagenesis (ATMT). Biological screening identified four mutants which were strongly reduced in virulence on wheat. Whole genome re-sequencing defined the positions of the T-DNA insertion events and revealed several unlinked mutations potentially affecting gene functions. Remarkably, two independent reduced virulence mutant strains, with similarly altered stress sensitivities and aberrant hyphal growth phenotypes, were found to have a distinct loss of function mutations in the ZtSSK2 MAPKKK gene. One mutant strain had a direct T-DNA insertion affecting the predicted protein's N-terminus, while the other possessed an unlinked frameshift mutation towards the C-terminus. We used genetic complementation to restore both strains' wild-type (WT) function (virulence, morphogenesis, and stress response). We demonstrated that ZtSSK2 has a non-redundant function with ZtSTE11 in virulence through the biochemical activation of the stress-activated HOG1 MAPK pathway. Moreover, we present data suggesting that SSK2 has a unique role in activating this pathway in response to specific stresses. Finally, dual RNAseq-based transcriptome profiling of WT and SSK2 mutant strains revealed many HOG1-dependent transcriptional changes in the fungus during early infection and suggested that the host response does not discriminate between WT and mutant strains during this early phase. Together these data define new genes implicated in the virulence of the pathogen and emphasise the importance of a whole genome sequencing step in mutagenomic discovery pipelines.
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Affiliation(s)
- Hannah R. Blyth
- Protecting Crops and the Environment, Rothamsted Research, Harpenden, United Kingdom
| | - Dan Smith
- Protecting Crops and the Environment, Rothamsted Research, Harpenden, United Kingdom
| | - Robert King
- Protecting Crops and the Environment, Rothamsted Research, Harpenden, United Kingdom
| | - Carlos Bayon
- Protecting Crops and the Environment, Rothamsted Research, Harpenden, United Kingdom
| | - Tom Ashfield
- Crop Health and Protection (CHAP), Rothamsted Research, Harpenden, United Kingdom
| | - Hannah Walpole
- Bioimaging Unit, Rothamsted Research, Harpenden, United Kingdom
| | - Eudri Venter
- Bioimaging Unit, Rothamsted Research, Harpenden, United Kingdom
| | - Rumiana V. Ray
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Loughborough, United Kingdom
| | - Kostya Kanyuka
- Protecting Crops and the Environment, Rothamsted Research, Harpenden, United Kingdom
| | - Jason J. Rudd
- Protecting Crops and the Environment, Rothamsted Research, Harpenden, United Kingdom
- *Correspondence: Jason J. Rudd,
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3
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Fraser CJ, Whitehall SK. Heterochromatin in the fungal plant pathogen, Zymoseptoria tritici: Control of transposable elements, genome plasticity and virulence. Front Genet 2022; 13:1058741. [DOI: 10.3389/fgene.2022.1058741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 11/04/2022] [Indexed: 11/22/2022] Open
Abstract
Heterochromatin is a repressive chromatin state that plays key roles in the functional organisation of eukaryotic genomes. In fungal plant pathogens, effector genes that are required for host colonization tend to be associated with heterochromatic regions of the genome that are enriched with transposable elements. It has been proposed that the heterochromatin environment silences effector genes in the absence of host and dynamic chromatin remodelling facilitates their expression during infection. Here we discuss this model in the context of the key wheat pathogen, Zymoseptoria tritici. We cover progress in understanding the deposition and recognition of heterochromatic histone post translational modifications in Z. tritici and the role that heterochromatin plays in control of genome plasticity and virulence.
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4
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Montezano Fernandes F, Vieira de Queiroz M, Lopes da Silva L, Maria Queiroz Azevedo D, Luis Badel J, Couto Alfenas A. Chromosomal polymorphism of the Ceratocystis fimbriata species complex in Brazil. Fungal Genet Biol 2022; 162:103728. [PMID: 35932991 DOI: 10.1016/j.fgb.2022.103728] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 07/15/2022] [Accepted: 07/23/2022] [Indexed: 11/04/2022]
Abstract
Ceratocystis fimbriata is an important pathogen that causes wilt in several plant species. Despite the importance of this pathogen, knowledge about its karyotypic polymorphism and genomic architecture is limited. The main objective of this study was to investigate the karyotype of isolates of the C. fimbriata species complex from different host plants and geographical origins in Brazil. First, the identity of the isolates was confirmed conducting multilocus sequence analysis (MLSA) phylogeny using β-tubulin (TUBB), translation elongation factor 1α (TEF-1α) and mating-type (MAT1 and MAT2) gene sequences. To investigate the chromosomal polymorphism, two conditions of pulsed-field gel electrophoresis (PFGE) were used and the karyotypes of the isolates obtained. The retrotransposon-microsatellite amplified polymorphism (REMAP) molecular marker was utilized to assess the genetic variability among isolates. In the MLSA utilizing the concatenated gene sequences, Ceratocystis cacaofunesta and C. fimbriata formed separate clades, but considerable variation among C. fimbriata isolates was observed. Polymorphism in chromosome number and size was found, indicating the existence of genomic differences among isolates and occurrence of chromosomal rearrangements in the species complex. The number of chromosomes varied from seven to nine and the estimated minimum chromosome sizes were estimated to be between 2.7 to 6.0 Mbp. Small polymorphic chromosomes ranging from 1.2 to 1.8 Mbp were observed in all isolates, raising the hypothesis that they could be supernumerary chromosomes. REMAP analysis revealed a high genetic variability and that isolates from the same host tend to group together in a same cluster. Our results bring new insights into the chromosomal diversity and genome organization of the C. fimbriata complex.
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Affiliation(s)
- Fernando Montezano Fernandes
- Laboratory of Forest Pathology, Department of Plant Pathology, Universidade Federal de Viçosa, Minas Gerais State, 36570-900, Brazil
| | - Marisa Vieira de Queiroz
- Laboratory of Molecular Genetics of Microorganisms, Department of Microbiology, Universidade Federal de Viçosa, Minas Gerais State, 36570-900, Brazil
| | - Leandro Lopes da Silva
- Laboratory of Molecular Genetics of Microorganisms, Department of Microbiology, Universidade Federal de Viçosa, Minas Gerais State, 36570-900, Brazil
| | - Daiana Maria Queiroz Azevedo
- Laboratory of Forest Pathology, Department of Plant Pathology, Universidade Federal de Viçosa, Minas Gerais State, 36570-900, Brazil
| | - Jorge Luis Badel
- Laboratory of Molecular Phytobacteriology, Department of Plant Pathology, Universidade Federal de Viçosa, Minas Gerais State, 36570-900, Brazil
| | - Acelino Couto Alfenas
- Laboratory of Forest Pathology, Department of Plant Pathology, Universidade Federal de Viçosa, Minas Gerais State, 36570-900, Brazil.
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5
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Characterization of Host-Specific Genes from Pine- and Grass-Associated Species of the Fusarium fujikuroi Species Complex. Pathogens 2022; 11:pathogens11080858. [PMID: 36014979 PMCID: PMC9415769 DOI: 10.3390/pathogens11080858] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 07/20/2022] [Accepted: 07/25/2022] [Indexed: 11/16/2022] Open
Abstract
The Fusarium fujikuroi species complex (FFSC) includes socioeconomically important pathogens that cause disease for numerous crops and synthesize a variety of secondary metabolites that can contaminate feedstocks and food. Here, we used comparative genomics to elucidate processes underlying the ability of pine-associated and grass-associated FFSC species to colonize tissues of their respective plant hosts. We characterized the identity, possible functions, evolutionary origins, and chromosomal positions of the host-range-associated genes encoded by the two groups of fungi. The 72 and 47 genes identified as unique to the respective genome groups were potentially involved in diverse processes, ranging from transcription, regulation, and substrate transport through to virulence/pathogenicity. Most genes arose early during the evolution of Fusarium/FFSC and were only subsequently retained in some lineages, while some had origins outside Fusarium. Although differences in the densities of these genes were especially noticeable on the conditionally dispensable chromosome of F. temperatum (representing the grass-associates) and F. circinatum (representing the pine-associates), the host-range-associated genes tended to be located towards the subtelomeric regions of chromosomes. Taken together, these results demonstrate that multiple mechanisms drive the emergence of genes in the grass- and pine-associated FFSC taxa examined. It also highlighted the diversity of the molecular processes potentially underlying niche-specificity in these and other Fusarium species.
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6
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Komluski J, Stukenbrock EH, Habig M. Non-Mendelian transmission of accessory chromosomes in fungi. Chromosome Res 2022; 30:241-253. [PMID: 35881207 PMCID: PMC9508043 DOI: 10.1007/s10577-022-09691-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 03/15/2022] [Accepted: 04/11/2022] [Indexed: 11/27/2022]
Abstract
Non-Mendelian transmission has been reported for various genetic elements, ranging from small transposons to entire chromosomes. One prime example of such a transmission pattern are B chromosomes in plants and animals. Accessory chromosomes in fungi are similar to B chromosomes in showing presence/absence polymorphism and being non-essential. How these chromosomes are transmitted during meiosis is however poorly understood—despite their often high impact on the fitness of the host. For several fungal organisms, a non-Mendelian transmission or a mechanistically unique meiotic drive of accessory chromosomes have been reported. In this review, we provide an overview of the possible mechanisms that can cause the non-Mendelian transmission or meiotic drives of fungal accessory chromosomes. We compare processes responsible for the non-Mendelian transmission of accessory chromosomes for different fungal eukaryotes and discuss the structural traits of fungal accessory chromosomes affecting their meiotic transmission. We conclude that research on fungal accessory chromosomes, due to their small size, ease of sequencing, and epigenetic profiling, can complement the study of B chromosomes in deciphering factors that influence and regulate the non-Mendelian transmission of entire chromosomes.
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Affiliation(s)
- Jovan Komluski
- Environmental Genomics, Christian-Albrechts University of Kiel, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Eva H Stukenbrock
- Environmental Genomics, Christian-Albrechts University of Kiel, Kiel, Germany.
- Max Planck Institute for Evolutionary Biology, Plön, Germany.
| | - Michael Habig
- Environmental Genomics, Christian-Albrechts University of Kiel, Kiel, Germany.
- Max Planck Institute for Evolutionary Biology, Plön, Germany.
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7
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Noar RD, Thomas E, Daub ME. Genetic Characteristics and Metabolic Interactions between Pseudocercospora fijiensis and Banana: Progress toward Controlling Black Sigatoka. PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11070948. [PMID: 35406928 PMCID: PMC9002641 DOI: 10.3390/plants11070948] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 03/23/2022] [Accepted: 03/25/2022] [Indexed: 05/10/2023]
Abstract
The international importance of banana and severity of black Sigatoka disease have led to extensive investigations into the genetic characteristics and metabolic interactions between the Dothideomycete Pseudocercospora fijiensis and its banana host. P. fijiensis was shown to have a greatly expanded genome compared to other Dothideomycetes, due to the proliferation of retrotransposons. Genome analysis suggests the presence of dispensable chromosomes that may aid in fungal adaptation as well as pathogenicity. Genomic research has led to the characterization of genes and metabolic pathways involved in pathogenicity, including: secondary metabolism genes such as PKS10-2, genes for mitogen-activated protein kinases such as Fus3 and Slt2, and genes for cell wall proteins such as glucosyl phosphatidylinositol (GPI) and glycophospholipid surface (Gas) proteins. Studies conducted on resistance mechanisms in banana have documented the role of jasmonic acid and ethylene pathways. With the development of banana transformation protocols, strategies for engineering resistance include transgenes expressing antimicrobial peptides or hydrolytic enzymes as well as host-induced gene silencing (HIGS) targeting pathogenicity genes. Pseudocercospora fijiensis has been identified as having high evolutionary potential, given its large genome size, ability to reproduce both sexually and asexually, and long-distance spore dispersal. Thus, multiple control measures are needed for the sustainable control of black Sigatoka disease.
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Affiliation(s)
- Roslyn D. Noar
- NSF Center for Integrated Pest Management, North Carolina State University, Raleigh, NC 27606, USA
- Correspondence:
| | - Elizabeth Thomas
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA; (E.T.); (M.E.D.)
| | - Margaret E. Daub
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA; (E.T.); (M.E.D.)
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8
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Phenotyping Mediterranean Durum Wheat Landraces for Resistance to Zymoseptoria tritici in Tunisia. Genes (Basel) 2022; 13:genes13020355. [PMID: 35205399 PMCID: PMC8872163 DOI: 10.3390/genes13020355] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/21/2022] [Accepted: 02/09/2022] [Indexed: 02/01/2023] Open
Abstract
Durum wheat landraces have huge potential for the identification of genetic factors valuable for improving resistance to biotic stresses. Tunisia is known as a hot spot for Septoria tritici blotch disease (STB), caused by the fungus Zymoseptoria tritici (Z. tritici). In this context, a collection of 3166 Mediterranean durum wheat landraces were evaluated at the seedling and adult stages for STB resistance in the 2016–2017 cropping season under field conditions in Kodia (Tunisia). Unadapted/susceptible accessions were eliminated to reach the final set of 1059 accessions; this was termed the Med-collection, which comprised accessions from 13 countries and was also screened in the 2018–2019 cropping season. The Med-collection showed high frequency of resistance reactions, among which over 50% showed an immune reaction (HR) at both seedling and adult growth stages. Interestingly, 92% of HR and R accessions maintained their resistance levels across the two years, confirming the highly significant correlation found between seedling- and adult-stage reactions. Plant Height was found to have a negative significant effect on adult-stage resistance, suggesting that either this trait can influence disease severity, or that it can be due to environmental/epidemiological factors. Accessions from Italy showed the highest variability, while those from Portugal, Spain and Tunisia showed the highest levels of resistance at both growth stages, suggesting that the latter accessions may harbor novel QTLs effective for STB resistance.
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9
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Kariyawasam GK, Wyatt N, Shi G, Liu S, Yan C, Ma Y, Zhong S, Rasmussen JB, Moolhuijzen P, Moffat CS, Friesen TL, Liu Z. A genome-wide genetic linkage map and reference quality genome sequence for a new race in the wheat pathogen Pyrenophora tritici-repentis. Fungal Genet Biol 2021; 152:103571. [PMID: 34015431 DOI: 10.1016/j.fgb.2021.103571] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 02/23/2021] [Accepted: 03/01/2021] [Indexed: 10/21/2022]
Abstract
Pyrenophora tritici-repentis is an ascomycete fungus that causes tan spot of wheat. The disease has a worldwide distribution and can cause significant yield and quality losses in wheat production. The fungal pathogen is homothallic in nature, which means it can undergo sexual reproduction by selfing to produce pseudothecia on wheat stubble for seasonal survival. Since homothallism precludes the development of bi-parental fungal populations, no genetic linkage map has been developed for P. tritici-repentis for mapping and map-based cloning of fungal virulence genes. In this work, we created two heterothallic strains by deleting one of the mating type genes in each of two parental isolates 86-124 (race 2) and AR CrossB10 (a new race) and developed a bi-parental fungal population between them. The draft genome sequences of the two parental isolates were aligned to the Pt-1C-BFP reference sequence to mine single nucleotide polymorphisms (SNPs). A total of 225 SNP markers were developed for genotyping the entire population. Additionally, 75 simple sequence repeat, and two gene markers were also developed and used in the genotyping. The resulting linkage map consisted of 13 linkage groups spanning 5,075.83 cM in genetic distance. Because the parental isolate AR CrossB10 is a new race and produces Ptr ToxC, it was sequenced using long-read sequencing platforms and de novo assembled into contigs. The majority of the contigs were further anchored into chromosomes with the aid of the linkage maps. The whole genome comparison of AR CrossB10 to the reference genome of M4 revealed a few chromosomal rearrangements. The genetic linkage map and the new AR CrossB10 genome sequence are valuable tools for gene cloning in P. tritici-repentis.
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Affiliation(s)
- Gayan K Kariyawasam
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108, USA
| | - Nathan Wyatt
- USDA-ARS Cereal Crops Research Unit, Edward T. Schafer Agricultural Research Center, Fargo, ND 58102, USA
| | - Gongjun Shi
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108, USA
| | - Sanzhen Liu
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
| | - Changhui Yan
- Department of Computer Science, North Dakota State University, Fargo, ND 58108, USA
| | - Yongchao Ma
- Department of Computer Science, North Dakota State University, Fargo, ND 58108, USA
| | - Shaobin Zhong
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108, USA
| | - Jack B Rasmussen
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108, USA
| | - Paula Moolhuijzen
- Center for Crop Disease and Management, Department of Environment and Agriculture, Curtin University, Bentley, Western Australia, Australia
| | - Caroline S Moffat
- Center for Crop Disease and Management, Department of Environment and Agriculture, Curtin University, Bentley, Western Australia, Australia
| | - Timothy L Friesen
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108, USA; USDA-ARS Cereal Crops Research Unit, Edward T. Schafer Agricultural Research Center, Fargo, ND 58102, USA
| | - Zhaohui Liu
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108, USA.
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10
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Eschenbrenner CJ, Feurtey A, Stukenbrock EH. Population Genomics of Fungal Plant Pathogens and the Analyses of Rapidly Evolving Genome Compartments. Methods Mol Biol 2021; 2090:337-355. [PMID: 31975174 DOI: 10.1007/978-1-0716-0199-0_14] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Genome sequencing of fungal pathogens have documented extensive variation in genome structure and composition between species and in many cases between individuals of the same species. This type of genomic variation can be adaptive for pathogens to rapidly evolve new virulence phenotypes. Analyses of genome-wide variation in fungal pathogen genomes rely on high quality assemblies and methods to detect and quantify structural variation. Population genomic studies in fungi have addressed the underlying mechanisms whereby structural variation can be rapidly generated. Transposable elements, high mutation and recombination rates as well as incorrect chromosome segregation during mitosis and meiosis contribute to extensive variation observed in many species. We here summarize key findings in the field of fungal pathogen genomics and we discuss methods to detect and characterize structural variants including an alignment-based pipeline to study variation in population genomic data.
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Affiliation(s)
- Christoph J Eschenbrenner
- Environmental Genomics, Christian-Albrechts University of Kiel, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Alice Feurtey
- Environmental Genomics, Christian-Albrechts University of Kiel, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Eva H Stukenbrock
- Environmental Genomics, Christian-Albrechts University of Kiel, Kiel, Germany.
- Max Planck Institute for Evolutionary Biology, Plön, Germany.
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11
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Ridenour JB, Möller M, Freitag M. Polycomb Repression without Bristles: Facultative Heterochromatin and Genome Stability in Fungi. Genes (Basel) 2020; 11:E638. [PMID: 32527036 PMCID: PMC7348808 DOI: 10.3390/genes11060638] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 05/27/2020] [Accepted: 06/04/2020] [Indexed: 02/06/2023] Open
Abstract
Genome integrity is essential to maintain cellular function and viability. Consequently, genome instability is frequently associated with dysfunction in cells and associated with plant, animal, and human diseases. One consequence of relaxed genome maintenance that may be less appreciated is an increased potential for rapid adaptation to changing environments in all organisms. Here, we discuss evidence for the control and function of facultative heterochromatin, which is delineated by methylation of histone H3 lysine 27 (H3K27me) in many fungi. Aside from its relatively well understood role in transcriptional repression, accumulating evidence suggests that H3K27 methylation has an important role in controlling the balance between maintenance and generation of novelty in fungal genomes. We present a working model for a minimal repressive network mediated by H3K27 methylation in fungi and outline challenges for future research.
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Affiliation(s)
| | | | - Michael Freitag
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis OR 97331, USA; (J.B.R.); (M.M.)
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12
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Fones HN, Bebber DP, Chaloner TM, Kay WT, Steinberg G, Gurr SJ. Threats to global food security from emerging fungal and oomycete crop pathogens. ACTA ACUST UNITED AC 2020; 1:332-342. [PMID: 37128085 DOI: 10.1038/s43016-020-0075-0] [Citation(s) in RCA: 147] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 04/09/2020] [Indexed: 11/09/2022]
Abstract
Emerging fungal and oomycete pathogens infect staple calorie crops and economically important commodity crops, thereby posing a significant risk to global food security. Our current agricultural systems - with emphasis on intensive monoculture practices - and globalized markets drive the emergence and spread of new pathogens and problematic traits, such as fungicide resistance. Climate change further promotes the emergence of pathogens on new crops and in new places. Here we review the factors affecting the introduction and spread of pathogens and current disease control strategies, illustrating these with the historic example of the Irish potato famine and contemporary examples of soybean rust, wheat blast and blotch, banana wilt and cassava root rot. Our Review looks to the future, summarizing what we see as the main challenges and knowledge gaps, and highlighting the direction that research must take to face the challenge of emerging crop pathogens.
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13
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Plaumann PL, Koch C. The Many Questions about Mini Chromosomes in Colletotrichum spp. PLANTS 2020; 9:plants9050641. [PMID: 32438596 PMCID: PMC7284448 DOI: 10.3390/plants9050641] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/08/2020] [Accepted: 05/14/2020] [Indexed: 11/16/2022]
Abstract
Many fungal pathogens carry accessory regions in their genome, which are not required for vegetative fitness. Often, although not always, these regions occur as relatively small chromosomes in different species. Such mini chromosomes appear to be a typical feature of many filamentous plant pathogens. Since these regions often carry genes coding for effectors or toxin-producing enzymes, they may be directly related to virulence of the respective pathogen. In this review, we outline the situation of small accessory chromosomes in the genus Colletotrichum, which accounts for ecologically important plant diseases. We summarize which species carry accessory chromosomes, their gene content, and chromosomal makeup. We discuss the large variation in size and number even between different isolates of the same species, their potential roles in host range, and possible mechanisms for intra- and interspecies exchange of these interesting genetic elements.
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14
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Covo S. Genomic Instability in Fungal Plant Pathogens. Genes (Basel) 2020; 11:E421. [PMID: 32295266 PMCID: PMC7230313 DOI: 10.3390/genes11040421] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 03/29/2020] [Accepted: 04/10/2020] [Indexed: 02/07/2023] Open
Abstract
Fungi and fungal-like organisms (oomycetes) that cause diseases in plants have impacted human communities for centuries and probably from the dawn of agriculture. In modern agriculture, there is a constant race between new strategies to manage fungal plant pathogens and their ability to adapt. An important component in this race is fungal genetic diversity. Mechanisms such as sexual and parasexual recombination that contribute to the creation of novel allele combinations in fungal plant pathogens are briefly discussed in the first part of this review. Advances in genomics have enabled the investigation of chromosomal aberrations of agriculturally important fungal isolates at the nucleotide level. Some of these cases are summarized in the second part of this review; it is claimed that the effect of chromosomal aberrations on pathogenicity should be studied mechanistically. More data on the effect of gene copy number variations on phenotypes that are relevant to agriculture are especially needed. Genome rearrangements through translocations have shaped the genome of fungal plant pathogens by creating lineage-specific chromosome territories encoding for genes participating in plant diseases. Pathogenicity chromosomes are unique cases of such lineage-specific genetic elements, interestingly these chromosomes can be transferred horizontally and thus transforming a non-pathogenic strain to a pathogenic one. The third part of this review describes our attempts to reveal mutators in fungal plant pathogens by identifying fungi that lack important DNA repair genes or respond to DNA damage in an unconventional way. We found that a group of fungal plant pathogens lack conserved genes that are needed for an important Holliday junction resolution pathway. In addition, in Fusarium oxysporum, the rate-limiting step in dNTP production is not induced under DNA replication stress. This is very different from organisms from bacteria to humans. It remains to be seen if these mechanisms promote genetic instability in fungal plant pathogens.
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Affiliation(s)
- Shay Covo
- Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University, Rehovot 76100001, Israel
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15
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Martin A, Moolhuijzen P, Tao Y, McIlroy J, Ellwood SR, Fowler RA, Platz GJ, Kilian A, Snyman L. Genomic Regions Associated with Virulence in Pyrenophora teres f. teres Identified by Genome-Wide Association Analysis and Biparental Mapping. PHYTOPATHOLOGY 2020; 110:881-891. [PMID: 31855502 DOI: 10.1094/phyto-10-19-0372-r] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Net form net blotch (NFNB), caused by the fungal pathogen Pyrenophora teres f. teres, is an important foliar disease present in all barley-producing regions of the world. This fungus is a hemibiotrophic and heterothallic ascomycete, where sexual recombination can lead to changes in disease expression in the host. Knowledge of the genetic architecture and genes involved in virulence is vital to increase the durability of NFNB resistance in barley cultivars. We used a genome-wide association mapping approach to characterize P. teres f. teres genomic regions associated with virulence in Australian barley cultivars. One hundred eighty-eight P. teres f. teres isolates collected across five Australian states were genotyped using Diversity Arrays Technology sequence markers and phenotyped across 20 different barley genotypes. Association mapping identified 14 different genomic regions associated with virulence, with the majority located on P. teres f. teres chromosomes 3 and 5 and one each present on chromosomes 1, 6, and 9. Four of the regions identified were confirmed by quantitative trait loci (QTL) mapping. The QTL regions are discussed in the context of their genomic architecture together with examination of their gene contents, which identified 20 predicted effectors. The number of QTL shown in this study at the population level clearly illustrates a complex genetic basis of P. teres f. teres virulence compared with pure necrotrophs, such as the wheat pathogens Parastagonospora nodorum and Parastagonospora tritici-repentis.
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Affiliation(s)
- Anke Martin
- Centre for Crop Health, University of Southern Queensland, Toowoomba, Queensland 4370, Australia
| | - Paula Moolhuijzen
- Centre for Crop & Disease Management, Department of Environment and Agriculture, Curtin University, Bentley, Western Australia 6102, Australia
| | - Yongfu Tao
- Hermitage Research Facility, Department of Agriculture & Fisheries, Warwick, Queensland 4370, Australia
| | - Judy McIlroy
- Hermitage Research Facility, Department of Agriculture & Fisheries, Warwick, Queensland 4370, Australia
| | - Simon R Ellwood
- Centre for Crop & Disease Management, Department of Environment and Agriculture, Curtin University, Bentley, Western Australia 6102, Australia
| | - Ryan A Fowler
- Hermitage Research Facility, Department of Agriculture & Fisheries, Warwick, Queensland 4370, Australia
| | - Greg J Platz
- Hermitage Research Facility, Department of Agriculture & Fisheries, Warwick, Queensland 4370, Australia
| | - Andrzej Kilian
- Diversity Arrays Technology, Bruce, Australian Capital Territory 2617, Australia
| | - Lisle Snyman
- Hermitage Research Facility, Department of Agriculture & Fisheries, Warwick, Queensland 4370, Australia
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16
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Chong P, Vichou AE, Schouten HJ, Meijer HJG, Arango Isaza RE, Kema GHJ. Pfcyp51 exclusively determines reduced sensitivity to 14α-demethylase inhibitor fungicides in the banana black Sigatoka pathogen Pseudocercospora fijiensis. PLoS One 2019; 14:e0223858. [PMID: 31622393 PMCID: PMC6797121 DOI: 10.1371/journal.pone.0223858] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Accepted: 09/30/2019] [Indexed: 11/27/2022] Open
Abstract
The haploid fungus Pseudocercospora fijiensis causes black Sigatoka in banana and is chiefly controlled by extensive fungicide applications, threatening occupational health and the environment. The 14α-Demethylase Inhibitors (DMIs) are important disease control fungicides, but they lose sensitivity in a rather gradual fashion, suggesting an underlying polygenic genetic mechanism. In spite of this, evidence found thus far suggests that P. fijiensis cyp51 gene mutations are the main responsible factor for sensitivity loss in the field. To better understand the mechanisms involved in DMI resistance, in this study we constructed a genetic map using DArTseq markers on two F1 populations generated by crossing two different DMI resistant strains with a sensitive strain. Analysis of the inheritance of DMI resistance in the F1 populations revealed two major and discrete DMI-sensitivity groups. This is an indicative of a single major responsible gene. Using the DMI-sensitivity scorings of both F1 populations and the generation of genetic linkage maps, the sensitivity causal factor was located in a single genetic region. Full agreement was found for genetic markers in either population, underlining the robustness of the approach. The two maps indicated a similar genetic region where the Pfcyp51 gene is found. Sequence analyses of the Pfcyp51 gene of the F1 populations also revealed a matching bimodal distribution with the DMI resistant. Amino acid substitutions in P. fijiensis CYP51 enzyme of the resistant progeny were previously correlated with the loss of DMI sensitivity. In addition, the resistant progeny inherited a Pfcyp51 gene promoter insertion, composed of a repeat element with a palindromic core, also previously correlated with increased gene expression. This genetic approach confirms that Pfcyp51 is the single explanatory gene for reduced sensitivity to DMI fungicides in the analysed P. fijiensis strains. Our study is the first genetic analysis to map the underlying genetic factors for reduced DMI efficacy.
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Affiliation(s)
- Pablo Chong
- ESPOL Polythecnic University, Escuela Superior Politécnica del Litoral, ESPOL, Centro de Investigaciones Biotecnológicas del Ecuador, Laboratorio de Fitopatología, Guayaquil, Ecuador
- Laboratory of Phytopathology, Wageningen University and Research, The Netherlands, Wageningen, the Netherlands
| | - Aikaterini-Eleni Vichou
- Laboratory of Phytopathology, Wageningen University and Research, The Netherlands, Wageningen, the Netherlands
| | - Henk J. Schouten
- Laboratory of Phytopathology, Wageningen University and Research, The Netherlands, Wageningen, the Netherlands
| | - Harold J. G. Meijer
- Laboratory of Phytopathology, Wageningen University and Research, The Netherlands, Wageningen, the Netherlands
| | - Rafael E. Arango Isaza
- Escuela de Biociencias, Faculta de Ciencias, Universidad Nacional de Colombia -Sede Medellín (UNALMED), Medellín, Colombia
- Unidad de biotecnología (UNALMED-CIB), Corporación para Investigaciones Biológicas, Medellín, Colombia
| | - Gert H. J. Kema
- Laboratory of Phytopathology, Wageningen University and Research, The Netherlands, Wageningen, the Netherlands
- * E-mail:
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17
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Fourie A, van der Nest MA, de Vos L, Wingfield MJ, Wingfield BD, Barnes I. QTL mapping of mycelial growth and aggressiveness to distinct hosts in Ceratocystis pathogens. Fungal Genet Biol 2019; 131:103242. [PMID: 31212023 DOI: 10.1016/j.fgb.2019.103242] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 06/07/2019] [Accepted: 06/12/2019] [Indexed: 10/26/2022]
Abstract
Some species of Ceratocystis display strong host specificity, such as C. fimbriata sensu stricto that is restricted to sweet potato (Ipomoea batatas) as host. In contrast, the closely related C. manginecans, infects Acacia mangium and Mangifera indica but is not pathogenic to I. batatas. Despite the economic importance of these fungi, knowledge regarding the genetic factors that influence their pathogenicity and host specificity is limited. A recent inheritance study, based on an interspecific cross between C. fimbriata and C. manginecans and the resultant 70 F1 progeny, confirmed that traits such as mycelial growth rate, spore production and aggressiveness on A. mangium and I. batatas are regulated by multiple genes. In the present study, a quantitative trait locus (QTL) analysis was performed to determine the genomic loci associated with these traits. All 70 progeny isolates were genotyped with SNP markers and a linkage map was constructed. The map contained 467 SNPs, distributed across nine linkage groups, with a total length of 1203 cm. Using the progeny genotypes and phenotypes, one QTL was identified on the linkage map for mycelial growth rate, one for aggressiveness to A. mangium and two for aggressiveness to I. batatas (P < 0.05). Two candidate genes, likely associated with mycelial growth rate, were identified in the QTL region. The three QTLs associated with aggressiveness to different hosts contained candidate genes involved in protein processing, detoxification and regions with effector genes and high transposable element density. The results provide a foundation for studies considering the function of genes regulating various quantitative traits in Ceratocystis.
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Affiliation(s)
- Arista Fourie
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0002, South Africa
| | - Magriet A van der Nest
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0002, South Africa; Biotechnology Platform, Agricultural Research Council, Private Bag X05, Onderstepoort 0110 0002, South Africa
| | - Lieschen de Vos
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0002, South Africa
| | - Michael J Wingfield
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0002, South Africa
| | - Brenda D Wingfield
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0002, South Africa
| | - Irene Barnes
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0002, South Africa.
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18
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van der Nest MA, Steenkamp ET, Roodt D, Soal NC, Palmer M, Chan WY, Wilken PM, Duong TA, Naidoo K, Santana QC, Trollip C, De Vos L, van Wyk S, McTaggart AR, Wingfield MJ, Wingfield BD. Genomic analysis of the aggressive tree pathogen Ceratocystis albifundus. Fungal Biol 2019; 123:351-363. [PMID: 31053324 DOI: 10.1016/j.funbio.2019.02.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 02/08/2019] [Accepted: 02/11/2019] [Indexed: 12/13/2022]
Abstract
The overall goal of this study was to determine whether the genome of an important plant pathogen in Africa, Ceratocystis albifundus, is structured into subgenomic compartments, and if so, to establish how these compartments are distributed across the genome. For this purpose, the publicly available genome of C. albifundus was complemented with the genome sequences for four additional isolates using the Illumina HiSeq platform. In addition, a reference genome for one of the individuals was assembled using both PacBio and Illumina HiSeq technologies. Our results showed a high degree of synteny between the five genomes, although several regions lacked detectable long-range synteny. These regions were associated with the presence of accessory genes, lower genetic similarity, variation in read-map depth, as well as transposable elements and genes associated with host-pathogen interactions (e.g. effectors and CAZymes). Such patterns are regarded as hallmarks of accelerated evolution, particularly of accessory subgenomic compartments in fungal pathogens. Our findings thus showed that the genome of C. albifundus is made-up of core and accessory subgenomic compartments, which is an important step towards characterizing its pangenome. This study also highlights the value of comparative genomics for understanding mechanisms that may underly and influence the biology and evolution of pathogens.
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Affiliation(s)
- Magriet A van der Nest
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa.
| | - Emma T Steenkamp
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Danielle Roodt
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Nicole C Soal
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Marike Palmer
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Wai-Yin Chan
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - P Markus Wilken
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Tuan A Duong
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Kershney Naidoo
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Quentin C Santana
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Conrad Trollip
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Lieschen De Vos
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Stephanie van Wyk
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Alistair R McTaggart
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Michael J Wingfield
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Brenda D Wingfield
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
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19
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Möller M, Schotanus K, Soyer JL, Haueisen J, Happ K, Stralucke M, Happel P, Smith KM, Connolly LR, Freitag M, Stukenbrock EH. Destabilization of chromosome structure by histone H3 lysine 27 methylation. PLoS Genet 2019; 15:e1008093. [PMID: 31009462 PMCID: PMC6510446 DOI: 10.1371/journal.pgen.1008093] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Revised: 05/10/2019] [Accepted: 03/15/2019] [Indexed: 01/23/2023] Open
Abstract
Chromosome and genome stability are important for normal cell function as instability often correlates with disease and dysfunction of DNA repair mechanisms. Many organisms maintain supernumerary or accessory chromosomes that deviate from standard chromosomes. The pathogenic fungus Zymoseptoria tritici has as many as eight accessory chromosomes, which are highly unstable during meiosis and mitosis, transcriptionally repressed, show enrichment of repetitive elements, and enrichment with heterochromatic histone methylation marks, e.g., trimethylation of H3 lysine 9 or lysine 27 (H3K9me3, H3K27me3). To elucidate the role of heterochromatin on genome stability in Z. tritici, we deleted the genes encoding the methyltransferases responsible for H3K9me3 and H3K27me3, kmt1 and kmt6, respectively, and generated a double mutant. We combined experimental evolution and genomic analyses to determine the impact of these deletions on chromosome and genome stability, both in vitro and in planta. We used whole genome sequencing, ChIP-seq, and RNA-seq to compare changes in genome and chromatin structure, and differences in gene expression between mutant and wildtype strains. Analyses of genome and ChIP-seq data in H3K9me3-deficient strains revealed dramatic chromatin reorganization, where H3K27me3 is mostly relocalized into regions that are enriched with H3K9me3 in wild type. Many genome rearrangements and formation of new chromosomes were found in the absence of H3K9me3, accompanied by activation of transposable elements. In stark contrast, loss of H3K27me3 actually increased the stability of accessory chromosomes under normal growth conditions in vitro, even without large scale changes in gene activity. We conclude that H3K9me3 is important for the maintenance of genome stability because it disallows H3K27me3 in regions considered constitutive heterochromatin. In this system, H3K27me3 reduces the overall stability of accessory chromosomes, generating a "metastable" state for these quasi-essential regions of the genome.
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Affiliation(s)
- Mareike Möller
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Fellow Group Environmental Genomics, Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Klaas Schotanus
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, United States of America
| | - Jessica L. Soyer
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, Thiverval-Grignon, France
| | - Janine Haueisen
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Fellow Group Environmental Genomics, Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Kathrin Happ
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
| | - Maja Stralucke
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
| | - Petra Happel
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Kristina M. Smith
- Department of Biology, Oregon State University—Cascades, Bend, OR, United States of America
| | - Lanelle R. Connolly
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, United States of America
| | - Michael Freitag
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, United States of America
| | - Eva H. Stukenbrock
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Fellow Group Environmental Genomics, Max Planck Institute for Evolutionary Biology, Plön, Germany
- * E-mail:
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20
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Haueisen J, Möller M, Eschenbrenner CJ, Grandaubert J, Seybold H, Adamiak H, Stukenbrock EH. Highly flexible infection programs in a specialized wheat pathogen. Ecol Evol 2019; 9:275-294. [PMID: 30680113 PMCID: PMC6342133 DOI: 10.1002/ece3.4724] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 10/04/2018] [Accepted: 10/05/2018] [Indexed: 12/21/2022] Open
Abstract
Many filamentous plant pathogens exhibit high levels of genomic variability, yet the impact of this variation on host-pathogen interactions is largely unknown. We have addressed host specialization in the wheat pathogen Zymoseptoria tritici. Our study builds on comparative analyses of infection and gene expression phenotypes of three isolates and reveals the extent to which genomic variation translates into phenotypic variation. The isolates exhibit genetic and genomic variation but are similarly virulent. By combining confocal microscopy, disease monitoring, staining of ROS, and comparative transcriptome analyses, we conducted a detailed comparison of the infection processes of these isolates in a susceptible wheat cultivar. We characterized four core infection stages: establishment, biotrophic growth, lifestyle transition, and necrotrophic growth and asexual reproduction that are shared by the three isolates. However, we demonstrate differentiated temporal and spatial infection development and significant differences in the expression profiles of the three isolates during the infection stages. More than 20% of the genes were differentially expressed and these genes were located significantly closer to transposable elements, suggesting an impact of epigenetic regulation. Further, differentially expressed genes were enriched in effector candidates suggesting that isolate-specific strategies for manipulating host defenses are present in Z. tritici. We demonstrate that individuals of a host-specialized pathogen have highly differentiated infection programs characterized by flexible infection development and functional redundancy. This illustrates how high genetic diversity in pathogen populations results in highly differentiated infection phenotypes, which fact needs to be acknowledged to understand host-pathogen interactions and pathogen evolution.
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Affiliation(s)
- Janine Haueisen
- Environmental Genomics GroupMax Planck Institute for Evolutionary BiologyPlönGermany
- Environmental Genomics GroupChristian‐Albrechts University KielKielGermany
| | - Mareike Möller
- Environmental Genomics GroupMax Planck Institute for Evolutionary BiologyPlönGermany
- Environmental Genomics GroupChristian‐Albrechts University KielKielGermany
| | - Christoph J. Eschenbrenner
- Environmental Genomics GroupMax Planck Institute for Evolutionary BiologyPlönGermany
- Environmental Genomics GroupChristian‐Albrechts University KielKielGermany
| | - Jonathan Grandaubert
- Environmental Genomics GroupMax Planck Institute for Evolutionary BiologyPlönGermany
- Fungal Biology and PathogenicityInstitute PasteurParisFrance
| | - Heike Seybold
- Environmental Genomics GroupMax Planck Institute for Evolutionary BiologyPlönGermany
- Environmental Genomics GroupChristian‐Albrechts University KielKielGermany
| | - Holger Adamiak
- Environmental Genomics GroupChristian‐Albrechts University KielKielGermany
| | - Eva H. Stukenbrock
- Environmental Genomics GroupMax Planck Institute for Evolutionary BiologyPlönGermany
- Environmental Genomics GroupChristian‐Albrechts University KielKielGermany
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21
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Habig M, Kema GHJ, Holtgrewe Stukenbrock E. Meiotic drive of female-inherited supernumerary chromosomes in a pathogenic fungus. eLife 2018; 7:e40251. [PMID: 30543518 PMCID: PMC6331196 DOI: 10.7554/elife.40251] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 12/13/2018] [Indexed: 01/03/2023] Open
Abstract
Meiosis is a key cellular process of sexual reproduction that includes pairing of homologous sequences. In many species however, meiosis can also involve the segregation of supernumerary chromosomes, which can lack a homolog. How these unpaired chromosomes undergo meiosis is largely unknown. In this study we investigated chromosome segregation during meiosis in the haploid fungus Zymoseptoria tritici that possesses a large complement of supernumerary chromosomes. We used isogenic whole chromosome deletion strains to compare meiotic transmission of chromosomes when paired and unpaired. Unpaired chromosomes inherited from the male parent as well as paired supernumerary chromosomes in general showed Mendelian inheritance. In contrast, unpaired chromosomes inherited from the female parent showed non-Mendelian inheritance but were amplified and transmitted to all meiotic products. We concluded that the supernumerary chromosomes of Z. tritici show a meiotic drive and propose an additional feedback mechanism during meiosis, which initiates amplification of unpaired female-inherited chromosomes.
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Affiliation(s)
- Michael Habig
- Environmental GenomicsChristian-Albrechts University of KielKielGermany
- Max Planck Institute for Evolutionary BiologyPlönGermany
| | - Gert HJ Kema
- Wageningen Plant ResearchWageningen University and ResearchWageningenThe Netherlands
- Laboratory of PhytopathologyWageningen University and ResearchWageningenThe Netherlands
| | - Eva Holtgrewe Stukenbrock
- Environmental GenomicsChristian-Albrechts University of KielKielGermany
- Max Planck Institute for Evolutionary BiologyPlönGermany
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22
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Möller M, Habig M, Freitag M, Stukenbrock EH. Extraordinary Genome Instability and Widespread Chromosome Rearrangements During Vegetative Growth. Genetics 2018; 210:517-529. [PMID: 30072376 PMCID: PMC6216587 DOI: 10.1534/genetics.118.301050] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 07/18/2018] [Indexed: 12/27/2022] Open
Abstract
The haploid genome of the pathogenic fungus Zymoseptoria tritici is contained on "core" and "accessory" chromosomes. While 13 core chromosomes are found in all strains, as many as eight accessory chromosomes show presence/absence variation and rearrangements among field isolates. The factors influencing these presence/absence polymorphisms are so far unknown. We investigated chromosome stability using experimental evolution, karyotyping, and genome sequencing. We report extremely high and variable rates of accessory chromosome loss during mitotic propagation in vitro and in planta Spontaneous chromosome loss was observed in 2 to >50% of cells during 4 weeks of incubation. Similar rates of chromosome loss in the closely related Zymoseptoria ardabiliae suggest that this extreme chromosome dynamic is a conserved phenomenon in the genus. Elevating the incubation temperature greatly increases instability of accessory and even core chromosomes, causing severe rearrangements involving telomere fusion and chromosome breakage. Chromosome losses do not affect the fitness of Zymoseptoria tritici in vitro, but some lead to increased virulence, suggesting an adaptive role of this extraordinary chromosome instability.
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Affiliation(s)
- Mareike Möller
- Environmental Genomics, Christian-Albrechts University, D-24118 Kiel, Germany
- Max Planck Fellow Group Environmental Genomics, Max Planck Institute for Evolutionary Biology, D-24306 Plön, Germany
| | - Michael Habig
- Environmental Genomics, Christian-Albrechts University, D-24118 Kiel, Germany
- Max Planck Fellow Group Environmental Genomics, Max Planck Institute for Evolutionary Biology, D-24306 Plön, Germany
| | - Michael Freitag
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331-7305
| | - Eva H Stukenbrock
- Environmental Genomics, Christian-Albrechts University, D-24118 Kiel, Germany
- Max Planck Fellow Group Environmental Genomics, Max Planck Institute for Evolutionary Biology, D-24306 Plön, Germany
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23
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Bertazzoni S, Williams AH, Jones DA, Syme RA, Tan KC, Hane JK. Accessories Make the Outfit: Accessory Chromosomes and Other Dispensable DNA Regions in Plant-Pathogenic Fungi. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:779-788. [PMID: 29664319 DOI: 10.1094/mpmi-06-17-0135-fi] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Fungal pathogen genomes can often be divided into core and accessory regions. Accessory regions ARs) may be comprised of either ARs (within core chromosomes (CCs) or wholly dispensable (accessory) chromosomes (ACs). Fungal ACs and ARs typically accumulate mutations and structural rearrangements more rapidly over time than CCs and many harbor genes relevant to host-pathogen interactions. These regions are of particular interest in plant pathology and include host-specific virulence factors and secondary metabolite synthesis gene clusters. This review outlines known ACs and ARs in fungal genomes, methods used for their detection, their common properties that differentiate them from the core genome, and what is currently known of their various roles in pathogenicity. Reports on the evolutionary processes generating and shaping AC and AR compartments are discussed, including repeat induced point mutation and breakage fusion bridge cycles. Previously ACs have been studied extensively within key genera, including Fusarium, Zymoseptoria, and Alternaria, but are growing in frequency of observation and perceived importance across a wider range of fungal species. Recent advances in sequencing technologies permit affordable genome assembly and resequencing of populations that will facilitate further discovery and routine screening of ACs.
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Affiliation(s)
- Stefania Bertazzoni
- 1 Centre for Crop & Disease Management, Curtin University, Perth, Western Australia, Australia; and
| | - Angela H Williams
- 1 Centre for Crop & Disease Management, Curtin University, Perth, Western Australia, Australia; and
| | - Darcy A Jones
- 1 Centre for Crop & Disease Management, Curtin University, Perth, Western Australia, Australia; and
| | - Robert A Syme
- 1 Centre for Crop & Disease Management, Curtin University, Perth, Western Australia, Australia; and
| | - Kar-Chun Tan
- 1 Centre for Crop & Disease Management, Curtin University, Perth, Western Australia, Australia; and
| | - James K Hane
- 1 Centre for Crop & Disease Management, Curtin University, Perth, Western Australia, Australia; and
- 2 Curtin Institute for Computation, Curtin University, Perth, Western Australia, Australia
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Fouché S, Plissonneau C, McDonald BA, Croll D. Meiosis Leads to Pervasive Copy-Number Variation and Distorted Inheritance of Accessory Chromosomes of the Wheat Pathogen Zymoseptoria tritici. Genome Biol Evol 2018; 10:1416-1429. [PMID: 29850789 PMCID: PMC6007412 DOI: 10.1093/gbe/evy100] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/22/2018] [Indexed: 12/11/2022] Open
Abstract
Meiosis is one of the most conserved molecular processes in eukaryotes. The fidelity of pairing and segregation of homologous chromosomes has a major impact on the proper transmission of genetic information. Aberrant chromosomal transmission can have major phenotypic consequences, yet the mechanisms are poorly understood. Fungi are excellent models to investigate processes of chromosomal transmission, because many species have highly polymorphic genomes that include accessory chromosomes. Inheritance of accessory chromosomes is often unstable and chromosomal losses have little impact on fitness. We analyzed chromosomal inheritance in 477 progeny coming from two crosses of the fungal wheat pathogen Zymoseptoria tritici. For this, we developed a high-throughput screening method based on restriction site-associated DNA sequencing that generated dense coverage of genetic markers along each chromosome. We identified rare instances of chromosomal duplications (disomy) in core chromosomes. Accessory chromosomes showed high overall frequencies of disomy. Chromosomal rearrangements were found exclusively on accessory chromosomes and were more frequent than disomy. Accessory chromosomes present in only one of the parents in an analyzed cross were inherited at significantly higher rates than the expected 1:1 segregation ratio. Both the chromosome and the parental background had significant impacts on the rates of disomy, losses, rearrangements, and distorted inheritance. We found that chromosomes with higher sequence similarity and lower repeat content were inherited more faithfully. The large number of rearranged progeny chromosomes identified in this species will enable detailed analyses of the mechanisms underlying chromosomal rearrangement.
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Affiliation(s)
- Simone Fouché
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Switzerland
| | - Clémence Plissonneau
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Switzerland
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, Thiverval-Grignon, France
| | - Bruce A McDonald
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Switzerland
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Switzerland
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25
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Ma X, Keller B, McDonald BA, Palma-Guerrero J, Wicker T. Comparative Transcriptomics Reveals How Wheat Responds to Infection by Zymoseptoria tritici. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:420-431. [PMID: 29090630 DOI: 10.1094/mpmi-10-17-0245-r] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The fungus Zymoseptoria tritici causes septoria tritici blotch (STB) on wheat, an important disease globally and the most damaging wheat disease in Europe. Despite the global significance of STB, the molecular basis of wheat defense against Z. tritici is poorly understood. Here, we use a comparative transcriptomic study to investigate how wheat responds to infection by four distinct strains of Z. tritici. We examined the response of wheat across the entire infection cycle, identifying both shared responses to the four strains and strain-specific responses. We found that the early asymptomatic phase is characterized by strong upregulation of genes encoding receptor-like kinases and pathogenesis-related proteins, indicating the onset of a defense response. We also identified genes that were differentially expressed among the four fungal strains, including genes related to defense. Genes involved in senescence were induced during both the asymptomatic phase and at late stages of infection, suggesting manipulation of senescence processes by both the plant and the pathogen. Our findings illustrate the need, when identifying important genes affecting disease resistance in plants, to include multiple pathogen strains.
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Affiliation(s)
- Xin Ma
- 1 Plant Pathology, Institute of Integrative Biology, ETH Zurich, 8092 Zurich, Switzerland; and
- 2 Department of Plant and Microbial Biology, University of Zurich, Zurich 8008, Switzerland
| | - Beat Keller
- 2 Department of Plant and Microbial Biology, University of Zurich, Zurich 8008, Switzerland
| | - Bruce A McDonald
- 1 Plant Pathology, Institute of Integrative Biology, ETH Zurich, 8092 Zurich, Switzerland; and
| | - Javier Palma-Guerrero
- 1 Plant Pathology, Institute of Integrative Biology, ETH Zurich, 8092 Zurich, Switzerland; and
| | - Thomas Wicker
- 2 Department of Plant and Microbial Biology, University of Zurich, Zurich 8008, Switzerland
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26
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Soyer JL, Balesdent MH, Rouxel T, Dean RA. To B or not to B: a tale of unorthodox chromosomes. Curr Opin Microbiol 2018; 46:50-57. [PMID: 29579575 DOI: 10.1016/j.mib.2018.01.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 01/19/2018] [Accepted: 01/24/2018] [Indexed: 01/21/2023]
Affiliation(s)
- Jessica L Soyer
- UMR BIOGER, INRA, AgroParisTech, Paris-Saclay University, Thiverval-Grignon, France
| | | | - Thierry Rouxel
- UMR BIOGER, INRA, AgroParisTech, Paris-Saclay University, Thiverval-Grignon, France
| | - Ralph A Dean
- Center for Integrated Fungal Research, North Carolina State University & Department of Entomology and Plant Pathology, North Carolina State University, United States.
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Abstract
The ability of an organism to replicate and segregate its genome with high fidelity is vital to its survival and for the production of future generations. Errors in either of these steps (replication or segregation) can lead to a change in ploidy or chromosome number. While these drastic genome changes can be detrimental to the organism, resulting in decreased fitness, they can also provide increased fitness during periods of stress. A change in ploidy or chromosome number can fundamentally change how a cell senses and responds to its environment. Here, we discuss current ideas in fungal biology that illuminate how eukaryotic genome size variation can impact the organism at a cellular and evolutionary level. One of the most fascinating observations from the past 2 decades of research is that some fungi have evolved the ability to tolerate large genome size changes and generate vast genomic heterogeneity without undergoing canonical meiosis.
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28
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Kema GHJ, Mirzadi Gohari A, Aouini L, Gibriel HAY, Ware SB, van den Bosch F, Manning-Smith R, Alonso-Chavez V, Helps J, Ben M'Barek S, Mehrabi R, Diaz-Trujillo C, Zamani E, Schouten HJ, van der Lee TAJ, Waalwijk C, de Waard MA, de Wit PJGM, Verstappen ECP, Thomma BPHJ, Meijer HJG, Seidl MF. Stress and sexual reproduction affect the dynamics of the wheat pathogen effector AvrStb6 and strobilurin resistance. Nat Genet 2018; 50:375-380. [PMID: 29434356 DOI: 10.1038/s41588-018-0052-9] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 01/06/2018] [Indexed: 11/09/2022]
Abstract
Host resistance and fungicide treatments are cornerstones of plant-disease control. Here, we show that these treatments allow sex and modulate parenthood in the fungal wheat pathogen Zymoseptoria tritici. We demonstrate that the Z. tritici-wheat interaction complies with the gene-for-gene model by identifying the effector AvrStb6, which is recognized by the wheat resistance protein Stb6. Recognition triggers host resistance, thus implying removal of avirulent strains from pathogen populations. However, Z. tritici crosses on wheat show that sex occurs even with an avirulent parent, and avirulence alleles are thereby retained in subsequent populations. Crossing fungicide-sensitive and fungicide-resistant isolates under fungicide pressure results in a rapid increase in resistance-allele frequency. Isolates under selection always act as male donors, and thus disease control modulates parenthood. Modeling these observations for agricultural and natural environments reveals extended durability of host resistance and rapid emergence of fungicide resistance. Therefore, fungal sex has major implications for disease control.
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Affiliation(s)
- Gerrit H J Kema
- Wageningen Plant Research, Wageningen University and Research, Wageningen, the Netherlands. .,Laboratory of Phytopathology, Wageningen University and Research, Wageningen, the Netherlands.
| | - Amir Mirzadi Gohari
- Wageningen Plant Research, Wageningen University and Research, Wageningen, the Netherlands.,Department of Plant Protection, College of Agriculture, University of Tehran, Karaj, Iran
| | - Lamia Aouini
- Wageningen Plant Research, Wageningen University and Research, Wageningen, the Netherlands
| | - Hesham A Y Gibriel
- Laboratory of Phytopathology, Wageningen University and Research, Wageningen, the Netherlands
| | - Sarah B Ware
- Wageningen Plant Research, Wageningen University and Research, Wageningen, the Netherlands.,Department of Biological Sciences, Benedictine University, Lisle, IL, USA
| | | | | | | | | | - Sarrah Ben M'Barek
- Laboratory of Molecular Plant Physiology, Biotechnology Center of Borj Cedria (CBBC), Hammam-Lif, Tunisia
| | - Rahim Mehrabi
- Department of Agricultural Biotechnology, College of Agriculture, Isfahan University of Technology, Isfahan, Iran
| | - Caucasella Diaz-Trujillo
- Wageningen Plant Research, Wageningen University and Research, Wageningen, the Netherlands.,Laboratory of Phytopathology, Wageningen University and Research, Wageningen, the Netherlands
| | - Elham Zamani
- Department of Plant Pathology, Tarbiat Modares University, Tehran, Iran
| | - Henk J Schouten
- Wageningen Plant Research, Wageningen University and Research, Wageningen, the Netherlands
| | - Theo A J van der Lee
- Wageningen Plant Research, Wageningen University and Research, Wageningen, the Netherlands
| | - Cees Waalwijk
- Wageningen Plant Research, Wageningen University and Research, Wageningen, the Netherlands
| | - Maarten A de Waard
- Laboratory of Phytopathology, Wageningen University and Research, Wageningen, the Netherlands
| | - Pierre J G M de Wit
- Laboratory of Phytopathology, Wageningen University and Research, Wageningen, the Netherlands
| | - Els C P Verstappen
- Wageningen Plant Research, Wageningen University and Research, Wageningen, the Netherlands
| | - Bart P H J Thomma
- Laboratory of Phytopathology, Wageningen University and Research, Wageningen, the Netherlands
| | - Harold J G Meijer
- Wageningen Plant Research, Wageningen University and Research, Wageningen, the Netherlands
| | - Michael F Seidl
- Laboratory of Phytopathology, Wageningen University and Research, Wageningen, the Netherlands
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Stewart EL, Croll D, Lendenmann MH, Sanchez‐Vallet A, Hartmann FE, Palma‐Guerrero J, Ma X, McDonald BA. Quantitative trait locus mapping reveals complex genetic architecture of quantitative virulence in the wheat pathogen Zymoseptoria tritici. MOLECULAR PLANT PATHOLOGY 2018; 19:201-216. [PMID: 27868326 PMCID: PMC6638037 DOI: 10.1111/mpp.12515] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We conducted a comprehensive analysis of virulence in the fungal wheat pathogen Zymoseptoria tritici using quantitative trait locus (QTL) mapping. High-throughput phenotyping based on automated image analysis allowed the measurement of pathogen virulence on a scale and with a precision that was not previously possible. Across two mapping populations encompassing more than 520 progeny, 540 710 pycnidia were counted and their sizes and grey values were measured. A significant correlation was found between pycnidia size and both spore size and number. Precise measurements of percentage leaf area covered by lesions provided a quantitative measure of host damage. Combining these large and accurate phenotypic datasets with a dense panel of restriction site-associated DNA sequencing (RADseq) genetic markers enabled us to genetically dissect pathogen virulence into components related to host damage and those related to pathogen reproduction. We showed that different components of virulence can be under separate genetic control. Large- and small-effect QTLs were identified for all traits, with some QTLs specific to mapping populations, cultivars and traits and other QTLs shared among traits within the same mapping population. We associated the presence of four accessory chromosomes with small, but significant, increases in several virulence traits, providing the first evidence for a meaningful function associated with accessory chromosomes in this organism. A large-effect QTL involved in host specialization was identified on chromosome 7, leading to the identification of candidate genes having a large effect on virulence.
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Affiliation(s)
- Ethan l. Stewart
- Plant Pathology Group, ETH Zürich, Universitätstrasse 2Zürich8092Switzerland
| | - Daniel Croll
- Plant Pathology Group, ETH Zürich, Universitätstrasse 2Zürich8092Switzerland
| | - Mark H. Lendenmann
- Plant Pathology Group, ETH Zürich, Universitätstrasse 2Zürich8092Switzerland
| | | | - Fanny E. Hartmann
- Plant Pathology Group, ETH Zürich, Universitätstrasse 2Zürich8092Switzerland
| | | | - Xin Ma
- Plant Pathology Group, ETH Zürich, Universitätstrasse 2Zürich8092Switzerland
| | - Bruce A. McDonald
- Plant Pathology Group, ETH Zürich, Universitätstrasse 2Zürich8092Switzerland
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30
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Forward Genetics Approach Reveals Host Genotype-Dependent Importance of Accessory Chromosomes in the Fungal Wheat Pathogen Zymoseptoria tritici. mBio 2017; 8:mBio.01919-17. [PMID: 29184021 PMCID: PMC5705923 DOI: 10.1128/mbio.01919-17] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The fungal wheat pathogen Zymoseptoria tritici possesses a large complement of accessory chromosomes showing presence/absence polymorphism among isolates. These chromosomes encode hundreds of genes; however, their functional role and why the chromosomes have been maintained over long evolutionary times are so far not known. In this study, we addressed the functional relevance of eight accessory chromosomes in reference isolate IPO323. We induced chromosome losses by inhibiting the β-tubulin assembly during mitosis using carbendazim and generated several independent isogenic strains, each lacking one of the accessory chromosomes. We confirmed chromosome losses by electrophoretic karyotyping and whole-genome sequencing. To assess the importance of the individual chromosomes during host infection, we performed in planta assays comparing disease development results in wild-type and chromosome mutant strains. Loss of the accessory chromosomes 14, 16, 18, 19, and 21 resulted in increased virulence on wheat cultivar Runal but not on cultivars Obelisk, Titlis, and Riband. Moreover, some accessory chromosomes affected the switch from biotrophy to necrotrophy as strains lacking accessory chromosomes 14, 18, 19, and 21 showed a significantly earlier onset of necrosis than the wild type on the Runal cultivar. In general, we observed that the timing of the lifestyle switch affects the fitness of Z. tritici. Taking the results together, this study was the first to use a forward-genetics approach to demonstrate a cultivar-dependent functional relevance of the accessory chromosomes of Z. tritici during host infection. Zymoseptoria tritici is a prominent fungal pathogen of wheat of worldwide distribution. This fungus shows a remarkable genome organization, with a large number of chromosomes that are present in only some isolates and therefore considered to be “accessory” chromosomes. To date, the function of these accessory chromosomes in Z. tritici has been unknown, although their maintenance in the species over evolutionary times suggests a functional relevance. Here we deleted whole accessory chromosomes to test the effect of these chromosomes on host specificity and virulence of the fungus. We show for the first time that some accessory chromosomes of Z. tritici affect the fitness of the fungus during host infection in a cultivar-dependent manner. These results show that the accessory chromosomes encode host-specific virulence determinants having a negative effect on fitness. Understanding the population dynamic of the accessory chromosomes and the molecular interaction of pathogen and plant traits is crucial to improve wheat-breeding strategies.
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31
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Mohammadi N, Mehrabi R, Mirzadi Gohari A, Mohammadi Goltapeh E, Safaie N, Kema GHJ. The ZtVf1 transcription factor regulates development and virulence in the foliar wheat pathogen Zymoseptoria tritici. Fungal Genet Biol 2017; 109:26-35. [PMID: 29031630 DOI: 10.1016/j.fgb.2017.10.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 10/03/2017] [Accepted: 10/11/2017] [Indexed: 10/18/2022]
Abstract
The dimorphic fungal pathogen, Zymoseptoria tritici undergoes discrete developmental changes to complete its life cycle on wheat. Molecular mechanisms underlying morphogenesis during infection process of Z. tritici are poorly understood. In this study, we have investigated the role of ZtVf1 gene encoding a transcription factor belonging to C2-H2 subfamily. In planta assays revealed that ZtVf1 is required for virulence. Reduced necrotic lesions and low pycnidia density within the lesions resulted in significantly reduced virulence of ZtVf1 mutants. Cytological analysis showed that the impaired virulence of ZtVf1 mutants attributed to reduced penetration and colonization along with hampered pycnidia differentiation. In vitro phenotyping showed that ZtVf1 deletion affects hyphal branching and biomass production suggesting that the reduced tissue colonization by the ZtVf1 mutant might be due to lower hyphal branching and less fungal biomass production. In addition, the majority of infected substomatal cavities by the ZtVf1 mutant filled with compacted mycelia mat that did not differentiate to mature pycnidia indicating that the impaired melanization negatively affected pycnidia formation and maturation. The ZtVf1 might target multiple genes belonging to different cellular processes whose identification is of eminent interest to increase our understanding of this pathosystem. Overall, the data provided in this study indicates that attenuated pathogenicity of ZtVf1 mutant is due to involvement of this gene in the regulation of both early and late stages of infection.
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Affiliation(s)
- Naser Mohammadi
- Department of Plant Pathology, Faculty of Agriculture, Tarbiat Modares University, P.O. Box 14115-111, Tehran, Iran; Dryland Agricultural Research Institute, Agricultural Research, Education & Extension Organization (ARREO), Maragheh, Iran
| | - Rahim Mehrabi
- Seed & Plant Improvement Institute, Agricultural Research, Education & Extension Organization (ARREO), P.O. Box 31585-4119, Karaj, Iran; Department of Biotechnology, College of Agriculture, Isfahan University of Technology, Isfahan, Iran.
| | - Amir Mirzadi Gohari
- Department of Plant Pathology, Faculty of Agricultural Sciences and Engineering, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
| | - Ebrahim Mohammadi Goltapeh
- Department of Plant Pathology, Faculty of Agriculture, Tarbiat Modares University, P.O. Box 14115-111, Tehran, Iran
| | - Naser Safaie
- Department of Plant Pathology, Faculty of Agriculture, Tarbiat Modares University, P.O. Box 14115-111, Tehran, Iran
| | - Gert H J Kema
- Laboratory of Phytopathology, Wageningen University and Research, 6700AA Wageningen, The Netherlands; Wageningen University and Research, Wageningen Plant Research, P.O. Box 16, 6700AA Wageningen, The Netherlands
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Tao SQ, Cao B, Tian CM, Liang YM. Comparative transcriptome analysis and identification of candidate effectors in two related rust species (Gymnosporangium yamadae and Gymnosporangium asiaticum). BMC Genomics 2017; 18:651. [PMID: 28830353 PMCID: PMC5567642 DOI: 10.1186/s12864-017-4059-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 08/14/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Rust fungi constitute the largest group of plant fungal pathogens. However, a paucity of data, including genomic sequences, transcriptome sequences, and associated molecular markers, hinders the development of inhibitory compounds and prevents their analysis from an evolutionary perspective. Gymnosporangium yamadae and G. asiaticum are two closely related rust fungal species, which are ecologically and economically important pathogens that cause apple rust and pear rust, respectively, proved to be devastating to orchards. In this study, we investigated the transcriptomes of these two Gymnosporangium species during the telial stage of their lifecycles. The aim of this study was to understand the evolutionary patterns of these two related fungi and to identify genes that developed by selection. RESULTS The transcriptomes of G. yamadae and G. asiaticum were generated from a mixture of RNA from three biological replicates of each species. We obtained 49,318 and 54,742 transcripts, with N50 values of 1957 and 1664, for G. yamadae and G. asiaticum, respectively. We also identified a repertoire of candidate effectors and other gene families associated with pathogenicity. A total of 4947 pairs of putative orthologues between the two species were identified. Estimation of the non-synonymous/synonymous substitution rate ratios for these orthologues identified 116 pairs with Ka/Ks values greater than1 that are under positive selection and 170 pairs with Ka/Ks values of 1 that are under neutral selection, whereas the remaining 4661 genes are subjected to purifying selection. We estimate that the divergence time between the two species is approximately 5.2 Mya. CONCLUSION This study constitutes a de novo assembly and comparative analysis between the transcriptomes of the two rust species G. yamadae and G. asiaticum. The results identified several orthologous genes, and many expressed genes were identified by annotation. Our analysis of Ka/Ks ratios identified orthologous genes subjected to positive or purifying selection. An evolutionary analysis of these two species provided a relatively precise divergence time. Overall, the information obtained in this study increases the genetic resources available for research on the genetic diversity of the Gymnosporangium genus.
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Affiliation(s)
- Si-Qi Tao
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University, Beijing, 100083, China
| | - Bin Cao
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University, Beijing, 100083, China
| | - Cheng-Ming Tian
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University, Beijing, 100083, China
| | - Ying-Mei Liang
- Museum of Beijing Forestry University, Beijing, 100083, China.
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33
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Möller M, Stukenbrock EH. Evolution and genome architecture in fungal plant pathogens. Nat Rev Microbiol 2017; 15:756-771. [DOI: 10.1038/nrmicro.2017.76] [Citation(s) in RCA: 219] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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34
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Mehrabi R, Mirzadi Gohari A, Kema GHJ. Karyotype Variability in Plant-Pathogenic Fungi. ANNUAL REVIEW OF PHYTOPATHOLOGY 2017; 55:483-503. [PMID: 28777924 DOI: 10.1146/annurev-phyto-080615-095928] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Recent advances in genetic and molecular technologies gradually paved the way for the transition from traditional fungal karyotyping to more comprehensive chromosome biology studies. Extensive chromosomal polymorphisms largely resulting from chromosomal rearrangements (CRs) are widely documented in fungal genomes. These extraordinary CRs in fungi generate substantial genome plasticity compared to other eukaryotic organisms. Here, we review the most recent findings on fungal CRs and their underlying mechanisms and discuss the functional consequences of CRs for adaptation, fungal evolution, host range, and pathogenicity of fungal plant pathogens in the context of chromosome biology. In addition to a complement of permanent chromosomes called core chromosomes, the genomes of many fungal pathogens comprise distinct unstable chromosomes called dispensable chromosomes (DCs) that also contribute to chromosome polymorphisms. Compared to the core chromosomes, the structural features of DCs usually differ for gene density, GC content, housekeeping genes, and recombination frequency. Despite their dispensability for normal growth and development, DCs have important biological roles with respect to pathogenicity in some fungi but not in others. Therefore, their evolutionary origin is also reviewed in relation to overall fungal physiology and pathogenicity.
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Affiliation(s)
- Rahim Mehrabi
- Seed and Plant Improvement Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
- Department of Biotechnology, College of Agriculture, Isfahan University of Technology, Isfahan, Iran
| | - Amir Mirzadi Gohari
- Department of Plant Pathology, Faculty of Agricultural Sciences and Engineering, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
- Wageningen Plant Research, Wageningen University and Research, 6700AA Wageningen, The Netherlands;
| | - Gert H J Kema
- Wageningen Plant Research, Wageningen University and Research, 6700AA Wageningen, The Netherlands;
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35
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Erlendson AA, Friedman S, Freitag M. A Matter of Scale and Dimensions: Chromatin of Chromosome Landmarks in the Fungi. Microbiol Spectr 2017; 5:10.1128/microbiolspec.FUNK-0054-2017. [PMID: 28752814 PMCID: PMC5536859 DOI: 10.1128/microbiolspec.funk-0054-2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Indexed: 02/06/2023] Open
Abstract
Chromatin and chromosomes of fungi are highly diverse and dynamic, even within species. Much of what we know about histone modification enzymes, RNA interference, DNA methylation, and cell cycle control was first addressed in Saccharomyces cerevisiae, Schizosaccharomyces pombe, Aspergillus nidulans, and Neurospora crassa. Here, we examine the three landmark regions that are required for maintenance of stable chromosomes and their faithful inheritance, namely, origins of DNA replication, telomeres and centromeres. We summarize the state of recent chromatin research that explains what is required for normal function of these specialized chromosomal regions in different fungi, with an emphasis on the silencing mechanism associated with subtelomeric regions, initiated by sirtuin histone deacetylases and histone H3 lysine 27 (H3K27) methyltransferases. We explore mechanisms for the appearance of "accessory" or "conditionally dispensable" chromosomes and contrast what has been learned from studies on genome-wide chromosome conformation capture in S. cerevisiae, S. pombe, N. crassa, and Trichoderma reesei. While most of the current knowledge is based on work in a handful of genetically and biochemically tractable model organisms, we suggest where major knowledge gaps remain to be closed. Fungi will continue to serve as facile organisms to uncover the basic processes of life because they make excellent model organisms for genetics, biochemistry, cell biology, and evolutionary biology.
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Affiliation(s)
- Allyson A. Erlendson
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331
| | - Steven Friedman
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331
| | - Michael Freitag
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331
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Palma-Guerrero J, Ma X, Torriani SFF, Zala M, Francisco CS, Hartmann FE, Croll D, McDonald BA. Comparative Transcriptome Analyses in Zymoseptoria tritici Reveal Significant Differences in Gene Expression Among Strains During Plant Infection. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2017; 30:231-244. [PMID: 28121239 DOI: 10.1094/mpmi-07-16-0146-r] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Zymoseptoria tritici is an ascomycete fungus that causes Septoria tritici blotch, a globally distributed foliar disease on wheat. Z. tritici populations are highly polymorphic and exhibit significant quantitative variation for virulence. Despite its importance, the genes responsible for quantitative virulence in this pathogen remain largely unknown. We investigated the expression profiles of four Z. tritici strains differing in virulence in an experiment conducted under uniform environmental conditions. Transcriptomes were compared at four different infection stages to characterize the regulation of gene families thought to be involved in virulence and to identify new virulence factors. The major components of the fungal infection transcriptome showed consistent expression profiles across strains. However, strain-specific regulation was observed for many genes, including some encoding putative virulence factors. We postulate that strain-specific regulation of virulence factors can determine the outcome of Z. tritici infections. We show that differences in gene expression may be major determinants of virulence variation among Z. tritici strains, adding to the already known contributions to virulence variation based on differences in gene sequence and gene presence/absence polymorphisms.
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Affiliation(s)
- Javier Palma-Guerrero
- 1 Plant Pathology, Institute of Integrative Biology, ETH Zurich, 8092 Zurich, Switzerland; and
| | - Xin Ma
- 1 Plant Pathology, Institute of Integrative Biology, ETH Zurich, 8092 Zurich, Switzerland; and
| | - Stefano F F Torriani
- 1 Plant Pathology, Institute of Integrative Biology, ETH Zurich, 8092 Zurich, Switzerland; and
- 2 Syngenta Crop Protection AG, Schaffhauserstrasse, 4332 Stein, Switzerland
| | - Marcello Zala
- 1 Plant Pathology, Institute of Integrative Biology, ETH Zurich, 8092 Zurich, Switzerland; and
| | - Carolina S Francisco
- 1 Plant Pathology, Institute of Integrative Biology, ETH Zurich, 8092 Zurich, Switzerland; and
| | - Fanny E Hartmann
- 1 Plant Pathology, Institute of Integrative Biology, ETH Zurich, 8092 Zurich, Switzerland; and
| | - Daniel Croll
- 1 Plant Pathology, Institute of Integrative Biology, ETH Zurich, 8092 Zurich, Switzerland; and
| | - Bruce A McDonald
- 1 Plant Pathology, Institute of Integrative Biology, ETH Zurich, 8092 Zurich, Switzerland; and
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Plissonneau C, Benevenuto J, Mohd-Assaad N, Fouché S, Hartmann FE, Croll D. Using Population and Comparative Genomics to Understand the Genetic Basis of Effector-Driven Fungal Pathogen Evolution. FRONTIERS IN PLANT SCIENCE 2017; 8:119. [PMID: 28217138 PMCID: PMC5289978 DOI: 10.3389/fpls.2017.00119] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 01/20/2017] [Indexed: 05/20/2023]
Abstract
Epidemics caused by fungal plant pathogens pose a major threat to agro-ecosystems and impact global food security. High-throughput sequencing enabled major advances in understanding how pathogens cause disease on crops. Hundreds of fungal genomes are now available and analyzing these genomes highlighted the key role of effector genes in disease. Effectors are small secreted proteins that enhance infection by manipulating host metabolism. Fungal genomes carry 100s of putative effector genes, but the lack of homology among effector genes, even for closely related species, challenges evolutionary and functional analyses. Furthermore, effector genes are often found in rapidly evolving chromosome compartments which are difficult to assemble. We review how population and comparative genomics toolsets can be combined to address these challenges. We highlight studies that associated genome-scale polymorphisms with pathogen lifestyles and adaptation to different environments. We show how genome-wide association studies can be used to identify effectors and other pathogenicity-related genes underlying rapid adaptation. We also discuss how the compartmentalization of fungal genomes into core and accessory regions shapes the evolution of effector genes. We argue that an understanding of genome evolution provides important insight into the trajectory of host-pathogen co-evolution.
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Affiliation(s)
- Clémence Plissonneau
- Plant Pathology, Institute of Integrative Biology, ETH ZurichZurich, Switzerland
- UMR, BIOGER, INRA, AgroParisTech, Université Paris-SaclayThiverval-Grignon, France
| | - Juliana Benevenuto
- College of Agriculture “Luiz de Queiroz”, University of São PauloSão Paulo, Brazil
| | - Norfarhan Mohd-Assaad
- Plant Pathology, Institute of Integrative Biology, ETH ZurichZurich, Switzerland
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan MalaysiaSelangor, Malaysia
| | - Simone Fouché
- Plant Pathology, Institute of Integrative Biology, ETH ZurichZurich, Switzerland
| | - Fanny E. Hartmann
- Plant Pathology, Institute of Integrative Biology, ETH ZurichZurich, Switzerland
| | - Daniel Croll
- Plant Pathology, Institute of Integrative Biology, ETH ZurichZurich, Switzerland
- Laboratory of Evolutionary Genetics, Institute of Biology, University of NeuchatelNeuchatel, Switzerland
- *Correspondence: Daniel Croll,
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Vlaardingerbroek I, Beerens B, Schmidt SM, Cornelissen BJC, Rep M. Dispensable chromosomes in Fusarium oxysporum f. sp. lycopersici. MOLECULAR PLANT PATHOLOGY 2016; 17:1455-1466. [PMID: 27271322 PMCID: PMC6638487 DOI: 10.1111/mpp.12440] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 06/02/2016] [Accepted: 06/03/2016] [Indexed: 05/23/2023]
Abstract
The genomes of many filamentous fungi consist of a 'core' part containing conserved genes essential for normal development as well as conditionally dispensable (CD) or lineage-specific (LS) chromosomes. In the plant-pathogenic fungus Fusarium oxysporum f. sp. lycopersici, one LS chromosome harbours effector genes that contribute to pathogenicity. We employed flow cytometry to select for events of spontaneous (partial) loss of either the two smallest LS chromosomes or two different core chromosomes. We determined the rate of spontaneous loss of the 'effector' LS chromosome in vitro at around 1 in 35 000 spores. In addition, a viable strain was obtained lacking chromosome 12, which is considered to be a part of the core genome. We also isolated strains carrying approximately 1-Mb deletions in the LS chromosomes and in the dispensable core chromosome. The large core chromosome 1 was never observed to sustain deletions over 200 kb. Whole-genome sequencing revealed that some of the sites at which the deletions occurred were the same in several independent strains obtained for the two chromosomes tested, indicating the existence of deletion hotspots. For the core chromosome, this deletion hotspot was the site of insertion of the marker used to select for loss events. Loss of the core chromosome did not affect pathogenicity, whereas loss of the effector chromosome led to a complete loss of pathogenicity.
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Affiliation(s)
- Ido Vlaardingerbroek
- Molecular Plant PathologyUniversity of AmsterdamAmsterdam1098 XH, the Netherlands
| | - Bas Beerens
- Molecular Plant PathologyUniversity of AmsterdamAmsterdam1098 XH, the Netherlands
| | - Sarah M. Schmidt
- Molecular Plant PathologyUniversity of AmsterdamAmsterdam1098 XH, the Netherlands
| | | | - Martijn Rep
- Molecular Plant PathologyUniversity of AmsterdamAmsterdam1098 XH, the Netherlands
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39
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Croll D, McDonald BA. The genetic basis of local adaptation for pathogenic fungi in agricultural ecosystems. Mol Ecol 2016; 26:2027-2040. [DOI: 10.1111/mec.13870] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Revised: 09/13/2016] [Accepted: 09/26/2016] [Indexed: 12/20/2022]
Affiliation(s)
- Daniel Croll
- Plant Pathology; Institute of Integrative Biology; ETH Zurich; 8092 Zurich Switzerland
| | - Bruce A. McDonald
- Plant Pathology; Institute of Integrative Biology; ETH Zurich; 8092 Zurich Switzerland
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40
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Noar RD, Daub ME. Transcriptome sequencing of Mycosphaerella fijiensis during association with Musa acuminata reveals candidate pathogenicity genes. BMC Genomics 2016; 17:690. [PMID: 27576702 PMCID: PMC5006380 DOI: 10.1186/s12864-016-3031-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 08/20/2016] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Mycosphaerella fijiensis, causative agent of the black Sigatoka disease of banana, is considered the most economically damaging banana disease. Despite its importance, the genetics of pathogenicity are poorly understood. Previous studies have characterized polyketide pathways with possible roles in pathogenicity. To identify additional candidate pathogenicity genes, we compared the transcriptome of this fungus during the necrotrophic phase of infection with that during saprophytic growth in medium. RESULTS Transcriptome analysis was conducted, and the functions of differentially expressed genes were predicted by identifying conserved domains, Gene Ontology (GO) annotation and GO enrichment analysis, Carbohydrate-Active EnZymes (CAZy) annotation, and identification of genes encoding effector-like proteins. The analysis showed that genes commonly involved in secondary metabolism have higher expression in infected leaf tissue, including genes encoding cytochrome P450s, short-chain dehydrogenases, and oxidoreductases in the 2-oxoglutarate and Fe(II)-dependent oxygenase superfamily. Other pathogenicity-related genes with higher expression in infected leaf tissue include genes encoding salicylate hydroxylase-like proteins, hydrophobic surface binding proteins, CFEM domain-containing proteins, and genes encoding secreted cysteine-rich proteins characteristic of effectors. More genes encoding amino acid transporters, oligopeptide transporters, peptidases, proteases, proteinases, sugar transporters, and proteins containing Domain of Unknown Function (DUF) 3328 had higher expression in infected leaf tissue, while more genes encoding inhibitors of peptidases and proteinases had higher expression in medium. Sixteen gene clusters with higher expression in leaf tissue were identified including clusters for the synthesis of a non-ribosomal peptide. A cluster encoding a novel fusicoccane was also identified. Two putative dispensable scaffolds were identified with a large proportion of genes with higher expression in infected leaf tissue, suggesting that they may play a role in pathogenicity. For two other scaffolds, no transcripts were detected in either condition, and PCR assays support the hypothesis that at least one of these scaffolds corresponds to a dispensable chromosome that is not required for survival or pathogenicity. CONCLUSIONS Our study revealed major changes in the transcriptome of Mycosphaerella fijiensis, when associating with its host compared to during saprophytic growth in medium. This analysis identified putative pathogenicity genes and also provides support for the existence of dispensable chromosomes in this fungus.
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Affiliation(s)
- Roslyn D. Noar
- Department of Plant Pathology, North Carolina State University, Raleigh, NC 27695-7616 USA
| | - Margaret E. Daub
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695-7612 USA
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Valente GT, Nakajima RT, Fantinatti BEA, Marques DF, Almeida RO, Simões RP, Martins C. B chromosomes: from cytogenetics to systems biology. Chromosoma 2016; 126:73-81. [PMID: 27558128 DOI: 10.1007/s00412-016-0613-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 08/10/2016] [Accepted: 08/15/2016] [Indexed: 01/01/2023]
Abstract
Though hundreds to thousands of reports have described the distribution of B chromosomes among diverse eukaryote groups, a comprehensive theory of their biological role has not yet clearly emerged. B chromosomes are classically understood as a sea of repetitive DNA sequences that are poor in genes and are maintained by a parasitic-drive mechanism during cell division. Recent developments in high-throughput DNA/RNA analyses have increased the resolution of B chromosome biology beyond those of classical and molecular cytogenetic methods; B chromosomes contain many transcriptionally active sequences, including genes, and can modulate the activity of autosomal genes. Furthermore, the most recent knowledge obtained from omics analyses, which is associated with a systemic view, has demonstrated that B chromosomes can influence cell biology in a complex way, possibly favoring their own maintenance and perpetuation.
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Affiliation(s)
- Guilherme T Valente
- Department of Bioprocess and Biotechnology, Agronomic Science School, UNESP - Sao Paulo State University, Botucatu, SP, 18610-307, Brazil
| | - Rafael T Nakajima
- Department of Morphology, Institute of Biosciences, UNESP - Sao Paulo State University, Sao Paulo, Botucatu, 18618-689, Brazil
| | - Bruno E A Fantinatti
- Department of Morphology, Institute of Biosciences, UNESP - Sao Paulo State University, Sao Paulo, Botucatu, 18618-689, Brazil
| | - Diego F Marques
- Department of Morphology, Institute of Biosciences, UNESP - Sao Paulo State University, Sao Paulo, Botucatu, 18618-689, Brazil
| | - Rodrigo O Almeida
- Department of Bioprocess and Biotechnology, Agronomic Science School, UNESP - Sao Paulo State University, Botucatu, SP, 18610-307, Brazil
| | - Rafael P Simões
- Department of Bioprocess and Biotechnology, Agronomic Science School, UNESP - Sao Paulo State University, Botucatu, SP, 18610-307, Brazil
| | - Cesar Martins
- Department of Morphology, Institute of Biosciences, UNESP - Sao Paulo State University, Sao Paulo, Botucatu, 18618-689, Brazil.
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Vanheule A, Audenaert K, Warris S, van de Geest H, Schijlen E, Höfte M, De Saeger S, Haesaert G, Waalwijk C, van der Lee T. Living apart together: crosstalk between the core and supernumerary genomes in a fungal plant pathogen. BMC Genomics 2016; 17:670. [PMID: 27552804 PMCID: PMC4994206 DOI: 10.1186/s12864-016-2941-6] [Citation(s) in RCA: 46] [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: 01/30/2016] [Accepted: 07/14/2016] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Eukaryotes display remarkable genome plasticity, which can include supernumerary chromosomes that differ markedly from the core chromosomes. Despite the widespread occurrence of supernumerary chromosomes in fungi, their origin, relation to the core genome and the reason for their divergent characteristics are still largely unknown. The complexity of genome assembly due to the presence of repetitive DNA partially accounts for this. RESULTS Here we use single-molecule real-time (SMRT) sequencing to assemble the genome of a prominent fungal wheat pathogen, Fusarium poae, including at least one supernumerary chromosome. The core genome contains limited transposable elements (TEs) and no gene duplications, while the supernumerary genome holds up to 25 % TEs and multiple gene duplications. The core genome shows all hallmarks of repeat-induced point mutation (RIP), a defense mechanism against TEs, specific for fungi. The absence of RIP on the supernumerary genome accounts for the differences between the two (sub)genomes, and results in a functional crosstalk between them. The supernumerary genome is a reservoir for TEs that migrate to the core genome, and even large blocks of supernumerary sequence (>200 kb) have recently translocated to the core. Vice versa, the supernumerary genome acts as a refuge for genes that are duplicated from the core genome. CONCLUSIONS For the first time, a mechanism was determined that explains the differences that exist between the core and supernumerary genome in fungi. Different biology rather than origin was shown to be responsible. A "living apart together" crosstalk exists between the core and supernumerary genome, accelerating chromosomal and organismal evolution.
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Affiliation(s)
- Adriaan Vanheule
- Department of Applied Biosciences, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
- Wageningen UR, Wageningen, The Netherlands
| | - Kris Audenaert
- Department of Applied Biosciences, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | | | | | | | - Monica Höfte
- Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Sarah De Saeger
- Department of Bioanalysis, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium
| | - Geert Haesaert
- Department of Applied Biosciences, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
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Arango Isaza RE, Diaz-Trujillo C, Dhillon B, Aerts A, Carlier J, Crane CF, V. de Jong T, de Vries I, Dietrich R, Farmer AD, Fortes Fereira C, Garcia S, Guzman M, Hamelin RC, Lindquist EA, Mehrabi R, Quiros O, Schmutz J, Shapiro H, Reynolds E, Scalliet G, Souza M, Stergiopoulos I, Van der Lee TAJ, De Wit PJGM, Zapater MF, Zwiers LH, Grigoriev IV, Goodwin SB, Kema GHJ. Combating a Global Threat to a Clonal Crop: Banana Black Sigatoka Pathogen Pseudocercospora fijiensis (Synonym Mycosphaerella fijiensis) Genomes Reveal Clues for Disease Control. PLoS Genet 2016; 12:e1005876. [PMID: 27512984 PMCID: PMC4981457 DOI: 10.1371/journal.pgen.1005876] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 01/27/2016] [Indexed: 12/03/2022] Open
Abstract
Black Sigatoka or black leaf streak disease, caused by the Dothideomycete fungus Pseudocercospora fijiensis (previously: Mycosphaerella fijiensis), is the most significant foliar disease of banana worldwide. Due to the lack of effective host resistance, management of this disease requires frequent fungicide applications, which greatly increase the economic and environmental costs to produce banana. Weekly applications in most banana plantations lead to rapid evolution of fungicide-resistant strains within populations causing disease-control failures throughout the world. Given its extremely high economic importance, two strains of P. fijiensis were sequenced and assembled with the aid of a new genetic linkage map. The 74-Mb genome of P. fijiensis is massively expanded by LTR retrotransposons, making it the largest genome within the Dothideomycetes. Melting-curve assays suggest that the genomes of two closely related members of the Sigatoka disease complex, P. eumusae and P. musae, also are expanded. Electrophoretic karyotyping and analyses of molecular markers in P. fijiensis field populations showed chromosome-length polymorphisms and high genetic diversity. Genetic differentiation was also detected using neutral markers, suggesting strong selection with limited gene flow at the studied geographic scale. Frequencies of fungicide resistance in fungicide-treated plantations were much higher than those in untreated wild-type P. fijiensis populations. A homologue of the Cladosporium fulvum Avr4 effector, PfAvr4, was identified in the P. fijiensis genome. Infiltration of the purified PfAVR4 protein into leaves of the resistant banana variety Calcutta 4 resulted in a hypersensitive-like response. This result suggests that Calcutta 4 could carry an unknown resistance gene recognizing PfAVR4. Besides adding to our understanding of the overall Dothideomycete genome structures, the P. fijiensis genome will aid in developing fungicide treatment schedules to combat this pathogen and in improving the efficiency of banana breeding programs.
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Affiliation(s)
- Rafael E. Arango Isaza
- Escuela de Biociencias, Universidad Nacional de Colombia, Medellín, Colombia
- Plant Biotechnology Unit, Corporación Para Investigaciones Biológicas, Medellín, Colombia
| | | | - Braham Dhillon
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana, United States of America
| | - Andrea Aerts
- US Department of Energy Joint Genome Institute, Walnut Creek, California, United States of America
| | | | - Charles F. Crane
- USDA-Agricultural Research Service, West Lafayette, Indiana, United States of America
| | - Tristan V. de Jong
- Plant Research International, Wageningen University and Research, Wageningen, The Netherlands
| | - Ineke de Vries
- Plant Research International, Wageningen University and Research, Wageningen, The Netherlands
| | - Robert Dietrich
- Syngenta Biotechnology Inc., Research Triangle Park, United States of America
| | - Andrew D. Farmer
- National Center for Genome Resources, Santa Fe, United States of America
| | | | | | - Mauricio Guzman
- National Banana Corporation of Costa Rica (CORBANA), La Rita de Pococí, Limón, Costa Rica
| | - Richard C. Hamelin
- Department of Forest and Conservation Sciences, The University of British Columbia, Vancouver, BC, Canada
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, Québec, QC, Canada
| | - Erika A. Lindquist
- US Department of Energy Joint Genome Institute, Walnut Creek, California, United States of America
| | - Rahim Mehrabi
- Department of Genetics, Seed and Plant Improvement Institute, Karaj, Iran
| | - Olman Quiros
- National Banana Corporation of Costa Rica (CORBANA), La Rita de Pococí, Limón, Costa Rica
| | - Jeremy Schmutz
- US Department of Energy Joint Genome Institute, Walnut Creek, California, United States of America
| | - Harris Shapiro
- US Department of Energy Joint Genome Institute, Walnut Creek, California, United States of America
| | - Elizabeth Reynolds
- General Bioinformatics at Syngenta Crop protection Jeallots Hill International Research Centre, Bracknell Berkshire, United Kingdom
| | | | - Manoel Souza
- Embrapa-LABEX Europe, Wageningen, The Netherlands
| | | | - Theo A. J. Van der Lee
- Plant Research International, Wageningen University and Research, Wageningen, The Netherlands
| | | | | | | | - Igor V. Grigoriev
- US Department of Energy Joint Genome Institute, Walnut Creek, California, United States of America
| | - Stephen B. Goodwin
- USDA-Agricultural Research Service, West Lafayette, Indiana, United States of America
| | - Gert H. J. Kema
- Plant Research International, Wageningen University and Research, Wageningen, The Netherlands
- Wageningen University, Laboratory of Phytopathology, Wageningen, The Netherlands
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Suffert F, Delestre G, Carpentier F, Gazeau G, Walker AS, Gélisse S, Duplaix C. Fashionably late partners have more fruitful encounters: Impact of the timing of co-infection and pathogenicity on sexual reproduction in Zymoseptoria tritici. Fungal Genet Biol 2016; 92:40-9. [DOI: 10.1016/j.fgb.2016.05.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 05/02/2016] [Accepted: 05/09/2016] [Indexed: 10/21/2022]
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45
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Utilizing Gene Tree Variation to Identify Candidate Effector Genes in Zymoseptoria tritici. G3-GENES GENOMES GENETICS 2016; 6:779-91. [PMID: 26837952 PMCID: PMC4825649 DOI: 10.1534/g3.115.025197] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Zymoseptoria tritici is a host-specific, necrotrophic pathogen of wheat. Infection by Z. tritici is characterized by its extended latent period, which typically lasts 2 wks, and is followed by extensive host cell death, and rapid proliferation of fungal biomass. This work characterizes the level of genomic variation in 13 isolates, for which we have measured virulence on 11 wheat cultivars with differential resistance genes. Between the reference isolate, IPO323, and the 13 Australian isolates we identified over 800,000 single nucleotide polymorphisms, of which ∼10% had an effect on the coding regions of the genome. Furthermore, we identified over 1700 probable presence/absence polymorphisms in genes across the Australian isolates using de novo assembly. Finally, we developed a gene tree sorting method that quickly identifies groups of isolates within a single gene alignment whose sequence haplotypes correspond with virulence scores on a single wheat cultivar. Using this method, we have identified < 100 candidate effector genes whose gene sequence correlates with virulence toward a wheat cultivar carrying a major resistance gene.
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46
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Cell biology of Zymoseptoria tritici: Pathogen cell organization and wheat infection. Fungal Genet Biol 2016; 79:17-23. [PMID: 26092785 PMCID: PMC4502449 DOI: 10.1016/j.fgb.2015.04.002] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 03/27/2015] [Accepted: 04/02/2015] [Indexed: 01/26/2023]
Abstract
Cell biology of the infection begins to shed light on the host–pathogen interaction. The cell biology of the fungal pathogen is highly understudied. Intensified cell biology research promises new fungicide targets and will help mode-of-action studies.
Cell biological research in the wheat pathogen Zymoseptoria tritici (formerly Mycosphaerella graminicola) has led to a good understanding of the histology of the infection process. Expression profiling and bioinformatic approaches, combined with molecular studies on signaling pathways, effectors and potential necrosis factors provides first insight into the complex interplay between the host and the pathogen. Cell biological studies will help to further our understanding of the infection strategy of the fungus. The cellular organization and intracellular dynamics of the fungus itself is largely unexplored. Insight into essential cellular processes within the pathogen will expand our knowledge of the basic biology of Z. tritici, thereby providing putative new anti-fungal targets.
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47
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Testa A, Oliver R, Hane J. Overview of genomic and bioinformatic resources for Zymoseptoria tritici. Fungal Genet Biol 2016; 79:13-6. [PMID: 26092784 DOI: 10.1016/j.fgb.2015.04.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 04/10/2015] [Accepted: 04/13/2015] [Indexed: 11/17/2022]
Abstract
Zymoseptoria tritici (syn. Mycosphaerella graminicola, Septoria tritici) is a haploid fungus belonging to the class Dothideomycetes. It is the causal agent of septoria leaf blotch - one of the world's most significant diseases of wheat. Here we review the genomic and bioinformatic resources that have been generated for Z. tritici. These include the whole-genome reference assembly for isolate IPO323, genome resequencing of alternate isolates, mitochondrial genome sequences, transcriptome sequences and expression data, and annotations of gene structure and function. We also highlight important advances in our fundamental knowledge of genome evolution and its effects on adaptation and pathogenicity in Z. tritici that have been facilitated by these resources.
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Affiliation(s)
- Alison Testa
- Centre for Crop and Disease Management, Curtin University, Perth, WA, Australia
| | - Richard Oliver
- Centre for Crop and Disease Management, Curtin University, Perth, WA, Australia
| | - James Hane
- Centre for Crop and Disease Management, Curtin University, Perth, WA, Australia; Curtin Institute for Computation, Curtin University, Perth, WA, Australia.
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48
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Mirzadi Gohari A, Ware SB, Wittenberg AHJ, Mehrabi R, Ben M'Barek S, Verstappen ECP, van der Lee TAJ, Robert O, Schouten HJ, de Wit PPJGM, Kema GHJ. Effector discovery in the fungal wheat pathogen Zymoseptoria tritici. MOLECULAR PLANT PATHOLOGY 2015; 16:931-45. [PMID: 25727413 PMCID: PMC6638447 DOI: 10.1111/mpp.12251] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Fungal plant pathogens, such as Zymoseptoria tritici (formerly known as Mycosphaerella graminicola), secrete repertoires of effectors to facilitate infection or trigger host defence mechanisms. The discovery and functional characterization of effectors provides valuable knowledge that can contribute to the design of new and effective disease management strategies. Here, we combined bioinformatics approaches with expression profiling during pathogenesis to identify candidate effectors of Z. tritici. In addition, a genetic approach was conducted to map quantitative trait loci (QTLs) carrying putative effectors, enabling the validation of both complementary strategies for effector discovery. In planta expression profiling revealed that candidate effectors were up-regulated in successive waves corresponding to consecutive stages of pathogenesis, contrary to candidates identified by QTL mapping that were, overall, expressed at low levels. Functional analyses of two top candidate effectors (SSP15 and SSP18) showed their dispensability for Z. tritici pathogenesis. These analyses reveal that generally adopted criteria, such as protein size, cysteine residues and expression during pathogenesis, may preclude an unbiased effector discovery. Indeed, genetic mapping of genomic regions involved in specificity render alternative effector candidates that do not match the aforementioned criteria, but should nevertheless be considered as promising new leads for effectors that are crucial for the Z. tritici-wheat pathosystem.
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Affiliation(s)
- Amir Mirzadi Gohari
- Wageningen University and Research Centre, Plant Research International, Droevendaalsesteeg 1, 6708, PB, Wageningen, The Netherlands
- Department of Plant Protection, College of Agriculture, University of Tehran, Plant Pathology Building, Karaj, Iran
| | - Sarah B Ware
- Wageningen University and Research Centre, Plant Research International, Droevendaalsesteeg 1, 6708, PB, Wageningen, The Netherlands
| | - Alexander H J Wittenberg
- Laboratory of Plant Breeding, Department of Plant Sciences, Wageningen University and Research Centre, Wageningen, the Netherlands
| | - Rahim Mehrabi
- Cereal Research Department, Seed and Plant Improvement Institute, PO Box 31585-4119, Karaj, Iran
| | - Sarrah Ben M'Barek
- Wageningen University and Research Centre, Plant Research International, Droevendaalsesteeg 1, 6708, PB, Wageningen, The Netherlands
- Center of Biotechnology of Borj Cedria, BP 901, Hammam-Lif, 2050, Tunisia
| | - Els C P Verstappen
- Wageningen University and Research Centre, Plant Research International, Droevendaalsesteeg 1, 6708, PB, Wageningen, The Netherlands
| | - Theo A J van der Lee
- Wageningen University and Research Centre, Plant Research International, Droevendaalsesteeg 1, 6708, PB, Wageningen, The Netherlands
| | - Olivier Robert
- Bioplante, Florimond Desprez, BP41, 59242, Cappelle-en-Pévèle, France
| | - Henk J Schouten
- Laboratory of Plant Breeding, Department of Plant Sciences, Wageningen University and Research Centre, Wageningen, the Netherlands
| | - Pierre P J G M de Wit
- Wageningen University and Research Centre, Laboratory of Phytopathology, P.O. Box 16, 6700, AA, Wageningen, The Netherlands
| | - Gert H J Kema
- Wageningen University and Research Centre, Plant Research International, Droevendaalsesteeg 1, 6708, PB, Wageningen, The Netherlands
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Schotanus K, Soyer JL, Connolly LR, Grandaubert J, Happel P, Smith KM, Freitag M, Stukenbrock EH. Histone modifications rather than the novel regional centromeres of Zymoseptoria tritici distinguish core and accessory chromosomes. Epigenetics Chromatin 2015; 8:41. [PMID: 26430472 PMCID: PMC4589918 DOI: 10.1186/s13072-015-0033-5] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 09/21/2015] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Supernumerary chromosomes have been found in many organisms. In fungi, these "accessory" or "dispensable" chromosomes are present at different frequencies in populations and are usually characterized by higher repetitive DNA content and lower gene density when compared to the core chromosomes. In the reference strain of the wheat pathogen, Zymoseptoria tritici, eight discrete accessory chromosomes have been found. So far, no functional role has been assigned to these chromosomes; however, they have existed as separate entities in the karyotypes of Zymoseptoria species over evolutionary time. In this study, we addressed what-if anything-distinguishes the chromatin of accessory chromosomes from core chromosomes. We used chromatin immunoprecipitation combined with high-throughput sequencing ("ChIP-seq") of DNA associated with the centromere-specific histone H3, CENP-A (CenH3), to identify centromeric DNA, and ChIP-seq with antibodies against dimethylated H3K4, trimethylated H3K9 and trimethylated H3K27 to determine the relative distribution and proportion of euchromatin, obligate and facultative heterochromatin, respectively. RESULTS Centromeres of the eight accessory chromosomes have the same sequence composition and structure as centromeres of the 13 core chromosomes and they are of similar length. Unlike those of most other fungi, Z. tritici centromeres are not composed entirely of repetitive DNA; some centromeres contain only unique DNA sequences, and bona fide expressed genes are located in regions enriched with CenH3. By fluorescence microscopy, we showed that centromeres of Z. tritici do not cluster into a single chromocenter during interphase. We found dramatically higher enrichment of H3K9me3 and H3K27me3 on the accessory chromosomes, consistent with the twofold higher proportion of repetitive DNA and poorly transcribed genes. In contrast, no single histone modification tested here correlated with the distribution of centromeric nucleosomes. CONCLUSIONS All centromeres are similar in length and composed of a mixture of unique and repeat DNA, and most contain actively transcribed genes. Centromeres, subtelomeric regions or telomere repeat length cannot account for the differences in transfer fidelity between core and accessory chromosomes, but accessory chromosomes are greatly enriched in nucleosomes with H3K27 trimethylation. Genes on accessory chromosomes appear to be silenced by trimethylation of H3K9 and H3K27.
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Affiliation(s)
- Klaas Schotanus
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Strasse 10, 35043 Marburg, Germany ; Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331-7303 USA ; Christian-Albrechts University of Kiel, Environmental Genomics, Am Botanischen Garten 9-11, 24118 Kiel, Germany ; Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306 Plön, Germany
| | - Jessica L Soyer
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Strasse 10, 35043 Marburg, Germany ; INRA, UMR 1290 INRA-AgroParisTech BIOGER, Avenue Lucien Brétignières, Thiverval-Grignon, 78850 France ; Christian-Albrechts University of Kiel, Environmental Genomics, Am Botanischen Garten 9-11, 24118 Kiel, Germany ; Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306 Plön, Germany
| | - Lanelle R Connolly
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331-7303 USA
| | - Jonathan Grandaubert
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Strasse 10, 35043 Marburg, Germany ; Christian-Albrechts University of Kiel, Environmental Genomics, Am Botanischen Garten 9-11, 24118 Kiel, Germany ; Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306 Plön, Germany
| | - Petra Happel
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Strasse 10, 35043 Marburg, Germany
| | - Kristina M Smith
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331-7303 USA
| | - Michael Freitag
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331-7303 USA
| | - Eva H Stukenbrock
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Strasse 10, 35043 Marburg, Germany ; Christian-Albrechts University of Kiel, Environmental Genomics, Am Botanischen Garten 9-11, 24118 Kiel, Germany ; Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306 Plön, Germany
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50
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Meiotic inheritance of a fungal supernumerary chromosome and its effect on sexual fertility in Nectria haematococca. Fungal Biol 2015; 119:929-939. [DOI: 10.1016/j.funbio.2015.07.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 06/25/2015] [Accepted: 07/14/2015] [Indexed: 11/20/2022]
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