1
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Stapley J, McDonald BA. Quantitative trait locus mapping of osmotic stress response in the fungal wheat pathogen Zymoseptoria tritici. G3 (BETHESDA, MD.) 2023; 13:jkad226. [PMID: 37774498 PMCID: PMC10700024 DOI: 10.1093/g3journal/jkad226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 09/19/2023] [Accepted: 09/20/2023] [Indexed: 10/01/2023]
Abstract
Osmotic stress is a ubiquitous and potent stress for all living organisms, but few studies have investigated the genetic basis of salt tolerance in filamentous fungi. The main aim of this study was to identify regions of the genome associated with tolerance to potassium chloride (KCl) in the wheat pathogen Zymoseptoria tritici. A secondary aim was to identify candidate genes affecting salt tolerance within the most promising chromosomal regions. We achieved these aims with a quantitative trait locus (QTL) mapping study using offspring from 2 crosses grown in vitro in the presence or absence of osmotic stress imposed by 0.75 M KCl. We identified significant QTL for most of the traits in both crosses. Several QTLs overlapped with QTL identified in earlier studies for other traits, and some QTL explained trait variation in both the control and salt stress environments. A significant QTL on chromosome 3 explained variation in colony radius at 8-day postinoculation (dpi) in the KCl environment as well as colony radius KCl tolerance at 8 dpi. The QTL peak had a high logarithm of the odds ratio (LOD) and encompassed an interval containing only 36 genes. Six of these genes present promising candidates for functional analyses. A gene ontology (GO) enrichment analysis of QTL unique to the KCl environment found evidence for the enrichment of functions involved in osmotic stress responses.
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Affiliation(s)
- Jessica Stapley
- Plant Pathology Group, Institute of Integrative Biology, ETH Zurich, Zürich 8092, Switzerland
| | - Bruce A McDonald
- Plant Pathology Group, Institute of Integrative Biology, ETH Zurich, Zürich 8092, Switzerland
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2
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Glad HM, Tralamazza SM, Croll D. The expression landscape and pangenome of long non-coding RNA in the fungal wheat pathogen Zymoseptoria tritici. Microb Genom 2023; 9. [PMID: 37991492 DOI: 10.1099/mgen.0.001136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2023] Open
Abstract
Long non-coding RNAs (lncRNAs) are regulatory molecules interacting in a wide array of biological processes. lncRNAs in fungal pathogens can be responsive to stress and play roles in regulating growth and nutrient acquisition. Recent evidence suggests that lncRNAs may also play roles in virulence, such as regulating pathogenicity-associated enzymes and on-host reproductive cycles. Despite the importance of lncRNAs, only a few model fungi have well-documented inventories of lncRNA. In this study, we apply a recent computational pipeline to predict high-confidence lncRNA candidates in Zymoseptoria tritici, an important global pathogen of wheat impacting global food production. We analyse genomic features of lncRNAs and the most likely associated processes through analyses of expression over a host infection cycle. We find that lncRNAs are frequently expressed during early infection, before the switch to necrotrophic growth. They are mostly located in facultative heterochromatic regions, which are known to contain many genes associated with pathogenicity. Furthermore, we find that lncRNAs are frequently co-expressed with genes that may be involved in responding to host defence signals, such as oxidative stress. Finally, we assess pangenome features of lncRNAs using four additional reference-quality genomes. We find evidence that the repertoire of expressed lncRNAs varies substantially between individuals, even though lncRNA loci tend to be shared at the genomic level. Overall, this study provides a repertoire and putative functions of lncRNAs in Z. tritici enabling future molecular genetics and functional analyses in an important pathogen.
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Affiliation(s)
- Hanna M Glad
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, 2000 Neuchâtel, Switzerland
| | - Sabina Moser Tralamazza
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, 2000 Neuchâtel, Switzerland
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, 2000 Neuchâtel, Switzerland
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3
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Meile L, Garrido-Arandia M, Bernasconi Z, Peter J, Schneller A, Bernasconi A, Alassimone J, McDonald BA, Sánchez-Vallet A. Natural variation in Avr3D1 from Zymoseptoria sp. contributes to quantitative gene-for-gene resistance and to host specificity. THE NEW PHYTOLOGIST 2023; 238:1562-1577. [PMID: 36529883 DOI: 10.1111/nph.18690] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 12/06/2022] [Indexed: 06/17/2023]
Abstract
Successful host colonization by plant pathogens requires the circumvention of host defense responses, frequently through sequence modifications in secreted pathogen proteins known as avirulence factors (Avrs). Although Avr sequences are often polymorphic, the contribution of these polymorphisms to virulence diversity in natural pathogen populations remains largely unexplored. We used molecular genetic tools to determine how natural sequence polymorphisms of the avirulence factor Avr3D1 in the wheat pathogen Zymoseptoria tritici contributed to adaptive changes in virulence. We showed that there is a continuous distribution in the magnitude of resistance triggered by different Avr3D1 isoforms and demonstrated that natural variation in an Avr gene can lead to a quantitative resistance phenotype. We further showed that homologues of Avr3D1 in two nonpathogenic sister species of Z. tritici are recognized by some wheat cultivars, suggesting that Avr-R gene-for-gene interactions can contribute to nonhost resistance. We suggest that the mechanisms underlying host range, qualitative resistance, and quantitative resistance are not exclusive.
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Affiliation(s)
- Lukas Meile
- Plant Pathology, Institute of Integrative Biology, ETH Zurich, Universitätstrasse 2, Zurich, 8092, Switzerland
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28223, Pozuelo de Alarcón, Madrid, Spain
| | - María Garrido-Arandia
- Plant Pathology, Institute of Integrative Biology, ETH Zurich, Universitätstrasse 2, Zurich, 8092, Switzerland
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28223, Pozuelo de Alarcón, Madrid, Spain
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid (UPM), 28040, Madrid, Spain
| | - Zoe Bernasconi
- Plant Pathology, Institute of Integrative Biology, ETH Zurich, Universitätstrasse 2, Zurich, 8092, Switzerland
| | - Jules Peter
- Plant Pathology, Institute of Integrative Biology, ETH Zurich, Universitätstrasse 2, Zurich, 8092, Switzerland
| | - Alissa Schneller
- Plant Pathology, Institute of Integrative Biology, ETH Zurich, Universitätstrasse 2, Zurich, 8092, Switzerland
| | - Alessio Bernasconi
- Plant Pathology, Institute of Integrative Biology, ETH Zurich, Universitätstrasse 2, Zurich, 8092, Switzerland
| | - Julien Alassimone
- Plant Pathology, Institute of Integrative Biology, ETH Zurich, Universitätstrasse 2, Zurich, 8092, Switzerland
| | - Bruce A McDonald
- Plant Pathology, Institute of Integrative Biology, ETH Zurich, Universitätstrasse 2, Zurich, 8092, Switzerland
| | - Andrea Sánchez-Vallet
- Plant Pathology, Institute of Integrative Biology, ETH Zurich, Universitätstrasse 2, Zurich, 8092, Switzerland
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28223, Pozuelo de Alarcón, Madrid, Spain
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4
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Resistance strategies for defense against Albugo candida causing white rust disease. Microbiol Res 2023; 270:127317. [PMID: 36805163 DOI: 10.1016/j.micres.2023.127317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 12/12/2022] [Accepted: 02/01/2023] [Indexed: 02/11/2023]
Abstract
Albugo candida, the causal organism of white rust, is an oomycete obligate pathogen infecting crops of Brassicaceae family occurred on aerial part, including vegetable and oilseed crops at all growth stages. The disease expression is characterized by local infection appearing on the abaxial region developing white or creamy yellow blister (sori) on leaves and systemic infections cause hypertrophy and hyperplasia leading to stag-head of reproductive organ. To overcome this problem, several disease management strategies like fungicide treatments were used in the field and disease-resistant varieties have also been developed using conventional and molecular breeding. Due to high variability among A. candida isolates, there is no single approach available to understand the diverse spectrum of disease symptoms. In absence of resistance sources against pathogen, repetitive cultivation of genetically-similar varieties locally tends to attract oomycete pathogen causing heavy yield losses. In the present review, a deep insight into the underlying role of the non-host resistance (NHR) defence mechanism available in plants, and the strategies to exploit available gene pools from plant species that are non-host to A. candida could serve as novel sources of resistance. This work summaries the current knowledge pertaining to the resistance sources available in non-host germ plasm, the understanding of defence mechanisms and the advance strategies covers molecular, biochemical and nature-based solutions in protecting Brassica crops from white rust disease.
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Hybrid de novo genome assembly and comparative genomics of three different isolates of Gnomoniopsis castaneae. Sci Rep 2023; 13:3356. [PMID: 36849528 PMCID: PMC9971261 DOI: 10.1038/s41598-023-30496-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 02/24/2023] [Indexed: 03/01/2023] Open
Abstract
The first genome assemblies of Gnomoniopsis castaneae (syn. G. smithogilvyi), the causal agent of chestnut brown rot of kernels, shoot blight and cankers, are provided here. Specifically, the complete genome of the Italian ex-type MUT401 isolate was compared to the draft genome of a second Italian isolate (GN01) and to the ICMP 14040 isolate from New Zealand. The three genome sequences were obtained through a hybrid assembly using both short Illumina reads and long Nanopore reads, their coding sequences were annotated and compared with each other and with other Diaporthales. The information offered by the genome assembly of the three isolates represents the base of data for further application related to -omics strategies of the fungus and to develop markers for population studies at a local and global scale.
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Oggenfuss U, Croll D. Recent transposable element bursts are associated with the proximity to genes in a fungal plant pathogen. PLoS Pathog 2023; 19:e1011130. [PMID: 36787337 PMCID: PMC9970103 DOI: 10.1371/journal.ppat.1011130] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 02/27/2023] [Accepted: 01/18/2023] [Indexed: 02/15/2023] Open
Abstract
The activity of transposable elements (TEs) contributes significantly to pathogen genome evolution. TEs often destabilize genome integrity but may also confer adaptive variation in pathogenicity or resistance traits. De-repression of epigenetically silenced TEs often initiates bursts of transposition activity that may be counteracted by purifying selection and genome defenses. However, how these forces interact to determine the expansion routes of TEs within a pathogen species remains largely unknown. Here, we analyzed a set of 19 telomere-to-telomere genomes of the fungal wheat pathogen Zymoseptoria tritici. Phylogenetic reconstruction and ancestral state estimates of individual TE families revealed that TEs have undergone distinct activation and repression periods resulting in highly uneven copy numbers between genomes of the same species. Most TEs are clustered in gene poor niches, indicating strong purifying selection against insertions near coding sequences, or as a consequence of insertion site preferences. TE families with high copy numbers have low sequence divergence and strong signatures of defense mechanisms (i.e., RIP). In contrast, small non-autonomous TEs (i.e., MITEs) are less impacted by defense mechanisms and are often located in close proximity to genes. Individual TE families have experienced multiple distinct burst events that generated many nearly identical copies. We found that a Copia element burst was initiated from recent copies inserted substantially closer to genes compared to older copies. Overall, TE bursts tended to initiate from copies in GC-rich niches that escaped inactivation by genomic defenses. Our work shows how specific genomic environments features provide triggers for TE proliferation in pathogen genomes.
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Affiliation(s)
- Ursula Oggenfuss
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
- * E-mail:
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7
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Wacker T, Helmstetter N, Wilson D, Fisher MC, Studholme DJ, Farrer RA. Two-speed genome evolution drives pathogenicity in fungal pathogens of animals. Proc Natl Acad Sci U S A 2023; 120:e2212633120. [PMID: 36595674 PMCID: PMC9926174 DOI: 10.1073/pnas.2212633120] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 11/14/2022] [Indexed: 01/05/2023] Open
Abstract
The origins and evolution of virulence in amphibian-infecting chytrids Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal) are largely unknown. Here, we use deep nanopore sequencing of Bsal and comparative genomics against 21 high-quality genome assemblies that span the fungal Chytridiomycota. We discover that Bsal has the most repeat-rich genome of the Chytridiomycota, comprising 40.9% repetitive elements; this genome has expanded to more than 3× the length of its conspecific Bd, with autonomous and fully functional LTR/Gypsy elements contributing significantly to the expansion. The M36 metalloprotease virulence factors are highly expanded (n = 177) in Bsal, most of which (53%) are flanked by transposable elements, suggesting they have a repeat-associated expansion. We find enrichment upstream of M36 metalloprotease genes of three novel repeat families belonging to the repeat superfamily of LINEs that are implicated with gene copy number variations. Additionally, Bsal has a highly compartmentalized genome architecture, with virulence factors enriched in gene-sparse/repeat-rich compartments, while core conserved genes are enriched in gene-rich/repeat-poor compartments. Genes upregulated during infection are primarily found in the gene-sparse/repeat-rich compartment in both Bd and Bsal. Furthermore, genes with signatures of positive selection in Bd are enriched in repeat-rich regions, suggesting these regions are a cradle for the evolution of chytrid pathogenicity. These are the hallmarks of two-speed genome evolution, and this study provides evidence of two-speed genomes in an animal pathogen, shedding light on the evolution of fungal pathogens of vertebrates driving global declines and extinctions.
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Affiliation(s)
- Theresa Wacker
- Medical Research Council Centre for Medical Mycology at the University of Exeter, ExeterEX4 4QD, United Kingdom
| | - Nicolas Helmstetter
- Medical Research Council Centre for Medical Mycology at the University of Exeter, ExeterEX4 4QD, United Kingdom
| | - Duncan Wilson
- Medical Research Council Centre for Medical Mycology at the University of Exeter, ExeterEX4 4QD, United Kingdom
| | - Matthew C. Fisher
- Medical Research Council (MRC) Centre for Global Infectious Disease Analysis, Imperial College London, LondonW12 0BZ, United Kingdom
| | - David J. Studholme
- Department of Biosciences, University of Exeter, ExeterEX4 4QD, United Kingdom
| | - Rhys A. Farrer
- Medical Research Council Centre for Medical Mycology at the University of Exeter, ExeterEX4 4QD, United Kingdom
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8
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Dubin CA, Voorhies M, Sil A, Teixeira MM, Barker BM, Brem RB. Genome Organization and Copy-Number Variation Reveal Clues to Virulence Evolution in Coccidioides posadasii. J Fungi (Basel) 2022; 8:jof8121235. [PMID: 36547568 PMCID: PMC9782707 DOI: 10.3390/jof8121235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 11/14/2022] [Accepted: 11/16/2022] [Indexed: 11/23/2022] Open
Abstract
The human fungal pathogen Coccidioides spp. causes valley fever, a treatment-refractory and sometimes deadly disease prevalent in arid regions of the western hemisphere. Fungal virulence in the mammalian host hinges on a switch between growth as hyphae and as large spherules containing infectious spores. How these virulence programs are encoded in the genome remains poorly understood. Drawing on Coccidioides genomic resources, we first discovered a new facet of genome organization in this system: spherule-gene islands, clusters of genes physically linked in the genome that exhibited specific mRNA induction in the spherule phase. Next, we surveyed copy-number variation genome-wide among strains of C. posadasii. Emerging from this catalog were spherule-gene islands with striking presence-absence differentiation between C. posadasii populations, a pattern expected from virulence factors subjected to different selective pressures across habitats. Finally, analyzing single-nucleotide differences across C. posadasii strains, we identified signatures of natural selection in spherule-expressed genes. Together, our data establish spherule-gene islands as candidate determinants of virulence and targets of selection in Coccidioides.
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Affiliation(s)
- Claire A. Dubin
- Department of Plant and Microbial Biology, UC Berkeley, Berkeley, CA 94720-3102, USA
| | - Mark Voorhies
- Department of Microbiology and Immunology, UC San Francisco, San Francisco, CA 94143, USA
| | - Anita Sil
- Department of Microbiology and Immunology, UC San Francisco, San Francisco, CA 94143, USA
| | - Marcus M. Teixeira
- The Translational Genomics Research Institute (TGen)-Affiliate of City of Hope, Flagstaff, AZ 85004, USA
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ 86011, USA
- Núcleo de Medicina Tropical, Faculdade de Medicina, Universidade de Brasília, Brasília 70910-900, Brazil
| | - Bridget M. Barker
- The Translational Genomics Research Institute (TGen)-Affiliate of City of Hope, Flagstaff, AZ 85004, USA
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Rachel B. Brem
- Department of Plant and Microbial Biology, UC Berkeley, Berkeley, CA 94720-3102, USA
- Correspondence:
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9
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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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10
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Wingfield BD, Berger DK, Coetzee MPA, Duong TA, Martin A, Pham NQ, van den Berg N, Wilken PM, Arun-Chinnappa KS, Barnes I, Buthelezi S, Dahanayaka BA, Durán A, Engelbrecht J, Feurtey A, Fourie A, Fourie G, Hartley J, Kabwe ENK, Maphosa M, Narh Mensah DL, Nsibo DL, Potgieter L, Poudel B, Stukenbrock EH, Thomas C, Vaghefi N, Welgemoed T, Wingfield MJ. IMA genome‑F17 : Draft genome sequences of an Armillaria species from Zimbabwe, Ceratocystis colombiana, Elsinoë necatrix, Rosellinia necatrix, two genomes of Sclerotinia minor, short‑read genome assemblies and annotations of four Pyrenophora teres isolates from barley grass, and a long-read genome assembly of Cercospora zeina. IMA Fungus 2022; 13:19. [PMID: 36411457 PMCID: PMC9677705 DOI: 10.1186/s43008-022-00104-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2022] [Indexed: 11/22/2022] Open
Affiliation(s)
- Brenda D. Wingfield
- grid.49697.350000 0001 2107 2298Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Dave K. Berger
- grid.49697.350000 0001 2107 2298Department of Plant and Soil Sciences, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0028 South Africa
| | - Martin P. A. Coetzee
- grid.49697.350000 0001 2107 2298Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Tuan A. Duong
- grid.49697.350000 0001 2107 2298Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Anke Martin
- grid.1048.d0000 0004 0473 0844Centre for Crop Health, University of Southern Queensland, Toowoomba, QLD 4350 Australia
| | - Nam Q. Pham
- grid.49697.350000 0001 2107 2298Department of Plant and Soil Sciences, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0028 South Africa
| | - Noelani van den Berg
- grid.49697.350000 0001 2107 2298Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - P. Markus Wilken
- grid.49697.350000 0001 2107 2298Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Kiruba Shankari Arun-Chinnappa
- grid.1048.d0000 0004 0473 0844Centre for Crop Health, University of Southern Queensland, Toowoomba, QLD 4350 Australia ,PerkinElmer Pty Ltd., Level 2, Building 5, Brandon Business Park, 530‑540, Springvale Road, Glen Waverley, VIC 3150 Australia
| | - Irene Barnes
- grid.49697.350000 0001 2107 2298Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Sikelela Buthelezi
- grid.49697.350000 0001 2107 2298Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | | | - Alvaro Durán
- Plant Health Program, Research and Development, Asia Pacific Resources International Holdings Ltd. (APRIL), Pangkalan Kerinci, Riau 28300 Indonesia
| | - Juanita Engelbrecht
- grid.49697.350000 0001 2107 2298Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Alice Feurtey
- grid.419520.b0000 0001 2222 4708Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306 Plön, Germany ,grid.9764.c0000 0001 2153 9986Environmental Genomics, Christian-Albrechts University of Kiel, 24118 Kiel, Germany
| | - Arista Fourie
- grid.49697.350000 0001 2107 2298Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Gerda Fourie
- grid.49697.350000 0001 2107 2298Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Jesse Hartley
- grid.49697.350000 0001 2107 2298Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Eugene N. K. Kabwe
- grid.49697.350000 0001 2107 2298Department of Biochemistry, Genetics and Microbiology, Centre for Bioinformatics and Computational Biology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Mkhululi Maphosa
- grid.49697.350000 0001 2107 2298Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Deborah L. Narh Mensah
- grid.49697.350000 0001 2107 2298Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa ,grid.423756.10000 0004 1764 1672CSIR, Food Research Institute, Accra, Ghana
| | - David L. Nsibo
- grid.49697.350000 0001 2107 2298Department of Plant and Soil Sciences, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0028 South Africa
| | - Lizel Potgieter
- grid.419520.b0000 0001 2222 4708Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306 Plön, Germany ,grid.9764.c0000 0001 2153 9986Environmental Genomics, Christian-Albrechts University of Kiel, 24118 Kiel, Germany
| | - Barsha Poudel
- grid.1048.d0000 0004 0473 0844Centre for Crop Health, University of Southern Queensland, Toowoomba, QLD 4350 Australia
| | - Eva H. Stukenbrock
- grid.419520.b0000 0001 2222 4708Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306 Plön, Germany ,grid.9764.c0000 0001 2153 9986Environmental Genomics, Christian-Albrechts University of Kiel, 24118 Kiel, Germany
| | - Chanel Thomas
- grid.49697.350000 0001 2107 2298Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Niloofar Vaghefi
- grid.1048.d0000 0004 0473 0844Centre for Crop Health, University of Southern Queensland, Toowoomba, QLD 4350 Australia ,grid.1008.90000 0001 2179 088XSchool of Agriculture and Food, University of Melbourne, Parkville, VIC 3010 Australia
| | - Tanya Welgemoed
- grid.49697.350000 0001 2107 2298Department of Biochemistry, Genetics and Microbiology, Centre for Bioinformatics and Computational Biology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Michael J. Wingfield
- grid.49697.350000 0001 2107 2298Department of Plant and Soil Sciences, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0028 South Africa
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11
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Li X, Mu K, Yang S, Wei J, Wang C, Yan W, Yuan F, Wang H, Han D, Kang Z, Zeng Q. Reduction of Rhizoctonia cerealis Infection on Wheat Through Host- and Spray-Induced Gene Silencing of an Orphan Secreted Gene. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2022; 35:803-813. [PMID: 36102883 DOI: 10.1094/mpmi-04-22-0075-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Rhizoctonia cerealis is a soilborne fungus that can cause sharp eyespot in wheat, resulting in massive yield losses found in many countries. Due to the lack of resistant cultivars, fungicides have been widely used to control this pathogen. However, chemical control is not environmentally friendly and is costly. Meanwhile, the lack of genetic transformation tools has hindered the functional characterization of virulence genes. In this study, we attempted to characterize the function of virulence genes by two transient methods, host-induced gene silencing (HIGS) and spray-induced gene silencing (SIGS), which use RNA interference to suppress the pathogenic development. We identified ten secretory orphan genes from the genome. After silencing these ten genes, only the RcOSP1 knocked-down plant significantly inhibited the growth of R. cerealis. We then described RcOSP1 as an effector that could impair wheat biological processes and suppress pathogen-associated molecular pattern-triggered immunity in the infection process. These findings confirm that HIGS and SIGS can be practical tools for researching R. cerealis virulence genes. [Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Xiang Li
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, China
| | - Keqing Mu
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, China
| | - Shuqing Yang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, China
| | - Jiajing Wei
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, China
| | - Congnawei Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, China
| | - Weiyi Yan
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, China
| | - Fengping Yuan
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, China
| | - Haiying Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, China
| | - Dejun Han
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, China
| | - Zhensheng Kang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, China
- Yangling Seed Industry Innovation Center, Yangling, Shaanxi 712100, China
| | - Qingdong Zeng
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, China
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12
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Jiang M, Li X, Dong X, Zu Y, Zhan Z, Piao Z, Lang H. Research Advances and Prospects of Orphan Genes in Plants. FRONTIERS IN PLANT SCIENCE 2022; 13:947129. [PMID: 35874010 PMCID: PMC9305701 DOI: 10.3389/fpls.2022.947129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 06/23/2022] [Indexed: 06/15/2023]
Abstract
Orphan genes (OGs) are defined as genes having no sequence similarity with genes present in other lineages. OGs have been regarded to play a key role in the development of lineage-specific adaptations and can also serve as a constant source of evolutionary novelty. These genes have often been found related to various stress responses, species-specific traits, special expression regulation, and also participate in primary substance metabolism. The advancement in sequencing tools and genome analysis methods has made the identification and characterization of OGs comparatively easier. In the study of OG functions in plants, significant progress has been made. We review recent advances in the fast evolving characteristics, expression modulation, and functional analysis of OGs with a focus on their role in plant biology. We also emphasize current challenges, adoptable strategies and discuss possible future directions of functional study of OGs.
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Affiliation(s)
- Mingliang Jiang
- School of Agriculture, Jilin Agricultural Science and Technology College, Jilin, China
| | - Xiaonan Li
- College of Horticulture, Shenyang Agricultural University, Shenyang, China
| | - Xiangshu Dong
- School of Agriculture, Yunnan University, Kunming, China
| | - Ye Zu
- College of Horticulture, Shenyang Agricultural University, Shenyang, China
| | - Zongxiang Zhan
- College of Horticulture, Shenyang Agricultural University, Shenyang, China
| | - Zhongyun Piao
- College of Horticulture, Shenyang Agricultural University, Shenyang, China
| | - Hong Lang
- School of Agriculture, Jilin Agricultural Science and Technology College, Jilin, China
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13
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Oggenfuss U, Badet T, Wicker T, Hartmann FE, Singh NK, Abraham L, Karisto P, Vonlanthen T, Mundt C, McDonald BA, Croll D. A population-level invasion by transposable elements triggers genome expansion in a fungal pathogen. eLife 2021; 10:e69249. [PMID: 34528512 PMCID: PMC8445621 DOI: 10.7554/elife.69249] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 08/28/2021] [Indexed: 12/16/2022] Open
Abstract
Genome evolution is driven by the activity of transposable elements (TEs). The spread of TEs can have deleterious effects including the destabilization of genome integrity and expansions. However, the precise triggers of genome expansions remain poorly understood because genome size evolution is typically investigated only among deeply divergent lineages. Here, we use a large population genomics dataset of 284 individuals from populations across the globe of Zymoseptoria tritici, a major fungal wheat pathogen. We built a robust map of genome-wide TE insertions and deletions to track a total of 2456 polymorphic loci within the species. We show that purifying selection substantially depressed TE frequencies in most populations, but some rare TEs have recently risen in frequency and likely confer benefits. We found that specific TE families have undergone a substantial genome-wide expansion from the pathogen's center of origin to more recently founded populations. The most dramatic increase in TE insertions occurred between a pair of North American populations collected in the same field at an interval of 25 years. We find that both genome-wide counts of TE insertions and genome size have increased with colonization bottlenecks. Hence, the demographic history likely played a major role in shaping genome evolution within the species. We show that both the activation of specific TEs and relaxed purifying selection underpin this incipient expansion of the genome. Our study establishes a model to recapitulate TE-driven genome evolution over deeper evolutionary timescales.
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Affiliation(s)
- Ursula Oggenfuss
- Laboratory of Evolutionary Genetics, Institute of Biology, University of NeuchâtelNeuchatelSwitzerland
| | - Thomas Badet
- Laboratory of Evolutionary Genetics, Institute of Biology, University of NeuchâtelNeuchatelSwitzerland
| | - Thomas Wicker
- Institute for Plant and Microbial Biology, University of ZurichZurichSwitzerland
| | - Fanny E Hartmann
- Ecologie Systématique Evolution, Bâtiment 360, Univ. Paris-Sud, AgroParisTech, CNRS, Université Paris-SaclayOrsayFrance
- Plant Pathology, Institute of Integrative Biology, ETH ZurichZurichSwitzerland
| | - Nikhil Kumar Singh
- Laboratory of Evolutionary Genetics, Institute of Biology, University of NeuchâtelNeuchatelSwitzerland
| | - Leen Abraham
- Laboratory of Evolutionary Genetics, Institute of Biology, University of NeuchâtelNeuchatelSwitzerland
| | - Petteri Karisto
- Plant Pathology, Institute of Integrative Biology, ETH ZurichZurichSwitzerland
| | - Tiziana Vonlanthen
- Plant Pathology, Institute of Integrative Biology, ETH ZurichZurichSwitzerland
| | - Christopher Mundt
- Department of Botany and Plant Pathology, Oregon State UniversityCorvallisUnited States
| | - Bruce A McDonald
- Plant Pathology, Institute of Integrative Biology, ETH ZurichZurichSwitzerland
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of NeuchâtelNeuchatelSwitzerland
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14
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Torres DE, Thomma BPHJ, Seidl MF. Transposable Elements Contribute to Genome Dynamics and Gene Expression Variation in the Fungal Plant Pathogen Verticillium dahliae. Genome Biol Evol 2021; 13:evab135. [PMID: 34100895 PMCID: PMC8290119 DOI: 10.1093/gbe/evab135] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/04/2021] [Indexed: 12/12/2022] Open
Abstract
Transposable elements (TEs) are a major source of genetic and regulatory variation in their host genome and are consequently thought to play important roles in evolution. Many fungal and oomycete plant pathogens have evolved dynamic and TE-rich genomic regions containing genes that are implicated in host colonization and adaptation. TEs embedded in these regions have typically been thought to accelerate the evolution of these genomic compartments, but little is known about their dynamics in strains that harbor them. Here, we used whole-genome sequencing data of 42 strains of the fungal plant pathogen Verticillium dahliae to systematically identify polymorphic TEs that may be implicated in genomic as well as in gene expression variation. We identified 2,523 TE polymorphisms and characterize a subset of 8% of the TEs as polymorphic elements that are evolutionary younger, less methylated, and more highly expressed when compared with the remaining 92% of the total TE complement. As expected, the polyrmorphic TEs are enriched in the adaptive genomic regions. Besides, we observed an association of polymorphic TEs with pathogenicity-related genes that localize nearby and that display high expression levels. Collectively, our analyses demonstrate that TE dynamics in V. dahliae contributes to genomic variation, correlates with expression of pathogenicity-related genes, and potentially impacts the evolution of adaptive genomic regions.
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Affiliation(s)
- David E Torres
- Theoretical Biology and Bioinformatics Group, Department of Biology, Utrecht University, The Netherlands
- Laboratory of Phytopathology, Wageningen University and Research, The Netherlands
| | - Bart P H J Thomma
- Laboratory of Phytopathology, Wageningen University and Research, The Netherlands
- Cluster of Excellence on Plant Sciences (CEPLAS), Institute for Plant Sciences, University of Cologne, Germany
| | - Michael F Seidl
- Theoretical Biology and Bioinformatics Group, Department of Biology, Utrecht University, The Netherlands
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15
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Asuke S, Magculia NJ, Inoue Y, Vy TTP, Tosa Y. Correlation of Genomic Compartments with Contrastive Modes of Functional Losses of Host Specificity Determinants During Pathotype Differentiation in Pyricularia oryzae. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:680-690. [PMID: 33522841 DOI: 10.1094/mpmi-12-20-0339-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The specificity between pathotypes of Pyricularia oryzae and genera of gramineous plants is governed by gene-for-gene interactions. Here, we show that avirulence genes involved in this host specificity have undergone different modes of functional losses dependent on or affected by genomic compartments harboring them. The avirulence of an Eleusine pathotype on wheat is controlled by five genes, including PWT3, which played a key role in the evolution of the Triticum pathotype (the wheat blast fungus). We cloned another gene using an association of its presence or absence with pathotypes and designated it as PWT6. PWT6 was widely distributed in a lineage composed of Eleusine and Eragrostis isolates but was completely absent in a lineage composed of Lolium and Triticum isolates. On the other hand, PWT3 homologs were present in all isolates, and their loss of function in Triticum isolates was caused by insertions of transposable elements or nucleotide substitutions. Analyses of whole-genome sequences of representative isolates revealed that these two genes were located in different genomic compartments; PWT6 was located in a repeat-rich region, while PWT3 was located in a repeat-poor region. These results suggest that the course of differentiation of the pathotypes in P. oryzae appears to be illustrated as processes of functional losses of avirulence genes but that modes of the losses are affected by genomic compartments in which they reside.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Soichiro Asuke
- Graduate School of Agricultural Science, Kobe University, Kobe 657-8501, Japan
| | | | - Yoshihiro Inoue
- Graduate School of Agricultural Science, Kobe University, Kobe 657-8501, Japan
| | - Trinh Thi Phuong Vy
- Graduate School of Agricultural Science, Kobe University, Kobe 657-8501, Japan
| | - Yukio Tosa
- Graduate School of Agricultural Science, Kobe University, Kobe 657-8501, Japan
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16
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Singh NK, Badet T, Abraham L, Croll D. Rapid sequence evolution driven by transposable elements at a virulence locus in a fungal wheat pathogen. BMC Genomics 2021; 22:393. [PMID: 34044766 PMCID: PMC8157644 DOI: 10.1186/s12864-021-07691-2] [Citation(s) in RCA: 15] [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: 02/16/2021] [Accepted: 05/07/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Plant pathogens cause substantial crop losses in agriculture production and threaten food security. Plants evolved the ability to recognize virulence factors and pathogens have repeatedly escaped recognition due rapid evolutionary change at pathogen virulence loci (i.e. effector genes). The presence of transposable elements (TEs) in close physical proximity of effector genes can have important consequences for gene regulation and sequence evolution. Species-wide investigations of effector gene loci remain rare hindering our ability to predict pathogen evolvability. RESULTS Here, we performed genome-wide association studies (GWAS) on a highly polymorphic mapping population of 120 isolates of Zymoseptoria tritici, the most damaging pathogen of wheat in Europe. We identified a major locus underlying significant variation in reproductive success of the pathogen and damage caused on the wheat cultivar Claro. The most strongly associated locus is intergenic and flanked by genes encoding a predicted effector and a serine-type endopeptidase. The center of the locus contained a highly dynamic region consisting of multiple families of TEs. Based on a large global collection of assembled genomes, we show that the virulence locus has undergone substantial recent sequence evolution. Large insertion and deletion events generated length variation between the flanking genes by a factor of seven (5-35 kb). The locus showed also strong signatures of genomic defenses against TEs (i.e. RIP) contributing to the rapid diversification of the locus. CONCLUSIONS In conjunction, our work highlights the power of combining GWAS and population-scale genome analyses to investigate major effect loci in pathogens.
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Affiliation(s)
- Nikhil Kumar Singh
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, 2000, Neuchâtel, Switzerland
| | - Thomas Badet
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, 2000, Neuchâtel, Switzerland
| | - Leen Abraham
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, 2000, Neuchâtel, Switzerland
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, 2000, Neuchâtel, Switzerland.
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17
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Gorkovskiy A, Verstrepen KJ. The Role of Structural Variation in Adaptation and Evolution of Yeast and Other Fungi. Genes (Basel) 2021; 12:699. [PMID: 34066718 PMCID: PMC8150848 DOI: 10.3390/genes12050699] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 04/30/2021] [Accepted: 05/04/2021] [Indexed: 01/12/2023] Open
Abstract
Mutations in DNA can be limited to one or a few nucleotides, or encompass larger deletions, insertions, duplications, inversions and translocations that span long stretches of DNA or even full chromosomes. These so-called structural variations (SVs) can alter the gene copy number, modify open reading frames, change regulatory sequences or chromatin structure and thus result in major phenotypic changes. As some of the best-known examples of SV are linked to severe genetic disorders, this type of mutation has traditionally been regarded as negative and of little importance for adaptive evolution. However, the advent of genomic technologies uncovered the ubiquity of SVs even in healthy organisms. Moreover, experimental evolution studies suggest that SV is an important driver of evolution and adaptation to new environments. Here, we provide an overview of the causes and consequences of SV and their role in adaptation, with specific emphasis on fungi since these have proven to be excellent models to study SV.
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Affiliation(s)
- Anton Gorkovskiy
- Laboratory for Genetics and Genomics, Centre of Microbial and Plant Genetics (CMPG), KU Leuven, Gaston Geenslaan 1, 3001 Leuven, Belgium;
- Laboratory for Systems Biology, VIB—KU Leuven Center for Microbiology, Bio-Incubator, Gaston Geenslaan 1, 3001 Leuven, Belgium
| | - Kevin J. Verstrepen
- Laboratory for Genetics and Genomics, Centre of Microbial and Plant Genetics (CMPG), KU Leuven, Gaston Geenslaan 1, 3001 Leuven, Belgium;
- Laboratory for Systems Biology, VIB—KU Leuven Center for Microbiology, Bio-Incubator, Gaston Geenslaan 1, 3001 Leuven, Belgium
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18
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Möller M, Habig M, Lorrain C, Feurtey A, Haueisen J, Fagundes WC, Alizadeh A, Freitag M, Stukenbrock EH. Recent loss of the Dim2 DNA methyltransferase decreases mutation rate in repeats and changes evolutionary trajectory in a fungal pathogen. PLoS Genet 2021; 17:e1009448. [PMID: 33750960 PMCID: PMC8016269 DOI: 10.1371/journal.pgen.1009448] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 04/01/2021] [Accepted: 02/26/2021] [Indexed: 01/04/2023] Open
Abstract
DNA methylation is found throughout all domains of life, yet the extent and function of DNA methylation differ among eukaryotes. Strains of the plant pathogenic fungus Zymoseptoria tritici appeared to lack cytosine DNA methylation (5mC) because gene amplification followed by Repeat-Induced Point mutation (RIP) resulted in the inactivation of the dim2 DNA methyltransferase gene. 5mC is, however, present in closely related sister species. We demonstrate that inactivation of dim2 occurred recently as some Z. tritici isolates carry a functional dim2 gene. Moreover, we show that dim2 inactivation occurred by a different path than previously hypothesized. We mapped the genome-wide distribution of 5mC in strains with or without functional dim2 alleles. Presence of functional dim2 correlates with high levels of 5mC in transposable elements (TEs), suggesting a role in genome defense. We identified low levels of 5mC in strains carrying non-functional dim2 alleles, suggesting that 5mC is maintained over time, presumably by an active Dnmt5 DNA methyltransferase. Integration of a functional dim2 allele in strains with mutated dim2 restored normal 5mC levels, demonstrating de novo cytosine methylation activity of Dim2. To assess the importance of 5mC for genome evolution, we performed an evolution experiment, comparing genomes of strains with high levels of 5mC to genomes of strains lacking functional dim2. We found that presence of a functional dim2 allele alters nucleotide composition by promoting C to T transitions (C→T) specifically at CpA (CA) sites during mitosis, likely contributing to TE inactivation. Our results show that 5mC density at TEs is a polymorphic trait in Z. tritici populations that can impact genome evolution.
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Affiliation(s)
- Mareike Möller
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Michael Habig
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Cécile Lorrain
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Alice Feurtey
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Janine Haueisen
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Wagner C. Fagundes
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Alireza Alizadeh
- Department of Plant Protection, Faculty of Agriculture, Azarbaijan Shahid Madani University, Tabriz, Iran
| | - 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 Institute for Evolutionary Biology, Plön, Germany
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19
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Reinhardt D, Roux C, Corradi N, Di Pietro A. Lineage-Specific Genes and Cryptic Sex: Parallels and Differences between Arbuscular Mycorrhizal Fungi and Fungal Pathogens. TRENDS IN PLANT SCIENCE 2021; 26:111-123. [PMID: 33011084 DOI: 10.1016/j.tplants.2020.09.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 08/29/2020] [Accepted: 09/08/2020] [Indexed: 05/25/2023]
Abstract
Arbuscular mycorrhizal fungi (AMF) live as obligate root symbionts on almost all land plants. They have long been regarded as ancient asexuals that have propagated clonally for millions of years. However, genomic studies in Rhizophagus irregularis and other AMF revealed many features indicative of sex. Surprisingly, comparative genomics of conspecific isolates of R. irregularis revealed an unexpected interstrain diversity, suggesting that AMF carry a high number of lineage-specific (LS) genes. Intriguingly, cryptic sex and LS genomic regions have previously been reported in a number of fungal pathogens of plants and humans. Here, we discuss these genomic similarities and highlight their potential relevance for AMF adaptation to the environment and for symbiotic functioning.
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Affiliation(s)
- Didier Reinhardt
- Department of Biology, University of Fribourg, Fribourg, Switzerland.
| | - Christophe Roux
- Laboratoire de Recherche en Sciences Végétales, UPS, CNRS, Université de Toulouse, Castanet-Tolosan 31326, France
| | - Nicolas Corradi
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Antonio Di Pietro
- Departamento de Genética, Universidad de Cordoba, 14071 Cordoba, Spain
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20
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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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21
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Turco S, Grottoli A, Drais MI, De Spirito C, Faino L, Reverberi M, Cristofori V, Mazzaglia A. Draft Genome Sequence of a New Fusarium Isolate Belonging to Fusarium tricinctum Species Complex Collected From Hazelnut in Central Italy. FRONTIERS IN PLANT SCIENCE 2021; 12:788584. [PMID: 34975974 PMCID: PMC8718101 DOI: 10.3389/fpls.2021.788584] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Accepted: 11/12/2021] [Indexed: 05/14/2023]
Abstract
In summer 2019, during a survey on the health status of a hazelnut orchard located in the Tuscia area (the province of Viterbo, Latium, Italy), nuts showing symptoms, such as brown-grayish spots at the bottom of the nuts progressing upward to the apex, and necrotic patches on the bracts and, sometimes, on the petioles, were found and collected for further studies. This syndrome is associated with the nut gray necrosis (NGN), whose main causal agent is Fusarium lateritium. Aiming to increase knowledge about this fungal pathogen, the whole-genome sequencing of a strain isolated from symptomatic hazelnut was performed using long Nanopore reads technology in combination with the higher precision of the Illumina reads, generating a high-quality genome assembly. The following phylogenetic and comparative genomics analysis suggested that this isolate is caused by the F. tricinctum species complex rather than F. lateritium one, as initially hypothesized. Thus, this study demonstrates that different Fusarium species can infect Corylus avellana producing the same symptomatology. In addition, it sheds light onto the genetic features of the pathogen in subject, clarifying facets about its biology, epidemiology, infection mechanisms, and host spectrum, with the future objective to develop specific and efficient control strategies.
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Affiliation(s)
- Silvia Turco
- Dipartimento di Scienze Agrarie e Forestali, Università degli Studi della Tuscia, Viterbo, Italy
- *Correspondence: Silvia Turco,
| | - Alessandro Grottoli
- Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria, Centro di Ricerca Difesa e Certificazione (CREA-DC), Rome, Italy
| | - Mounira Inas Drais
- Dipartimento di Scienze Agrarie e Forestali, Università degli Studi della Tuscia, Viterbo, Italy
| | - Carlo De Spirito
- Dipartimento di Scienze Agrarie e Forestali, Università degli Studi della Tuscia, Viterbo, Italy
| | - Luigi Faino
- Dipartimento di Biologia Ambientale, Sapienza Università di Roma, Rome, Italy
| | - Massimo Reverberi
- Dipartimento di Biologia Ambientale, Sapienza Università di Roma, Rome, Italy
| | - Valerio Cristofori
- Dipartimento di Scienze Agrarie e Forestali, Università degli Studi della Tuscia, Viterbo, Italy
| | - Angelo Mazzaglia
- Dipartimento di Scienze Agrarie e Forestali, Università degli Studi della Tuscia, Viterbo, Italy
- Angelo Mazzaglia,
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22
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Chromatin Dynamics Contribute to the Spatiotemporal Expression Pattern of Virulence Genes in a Fungal Plant Pathogen. mBio 2020; 11:mBio.02343-20. [PMID: 33024042 PMCID: PMC7542367 DOI: 10.1128/mbio.02343-20] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Fungal plant pathogens possess a large repertoire of genes encoding putative effectors, which are crucial for infection. Many of these genes are expressed at low levels in the absence of the host but are strongly induced at specific stages of the infection. The mechanisms underlying this transcriptional reprogramming remain largely unknown. We investigated the role of the genomic environment and associated chromatin modifications of effector genes in controlling their expression pattern in the fungal wheat pathogen Zymoseptoria tritici. Depending on their genomic location, effector genes are epigenetically repressed in the absence of the host and during the initial stages of infection. Derepression of effector genes occurs mainly during and after penetration of plant leaves and is associated with changes in histone modifications. Our work demonstrates the role of chromatin in shaping the expression of virulence components and, thereby, the interaction between fungal pathogens and their plant hosts. Dynamic changes in transcription profiles are key for the success of pathogens in colonizing their hosts. In many pathogens, genes associated with virulence, such as effector genes, are located in regions of the genome that are rich in transposable elements and heterochromatin. The contribution of chromatin modifications to gene expression in pathogens remains largely unknown. Using a combination of a reporter gene-based approach and chromatin immunoprecipitation, we show that the heterochromatic environment of effector genes in the fungal plant pathogen Zymoseptoria tritici is a key regulator of their specific spatiotemporal expression patterns. Enrichment in trimethylated lysine 27 of histone H3 dictates the repression of effector genes in the absence of the host. Chromatin decondensation during host colonization, featuring a reduction in this repressive modification, indicates a major role for epigenetics in effector gene induction. Our results illustrate that chromatin modifications triggered during host colonization determine the specific expression profile of effector genes at the cellular level and, hence, provide new insights into the regulation of virulence in fungal plant pathogens.
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Naranjo‐Ortiz MA, Gabaldón T. Fungal evolution: cellular, genomic and metabolic complexity. Biol Rev Camb Philos Soc 2020; 95:1198-1232. [PMID: 32301582 PMCID: PMC7539958 DOI: 10.1111/brv.12605] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 03/31/2020] [Accepted: 04/02/2020] [Indexed: 12/13/2022]
Abstract
The question of how phenotypic and genomic complexity are inter-related and how they are shaped through evolution is a central question in biology that historically has been approached from the perspective of animals and plants. In recent years, however, fungi have emerged as a promising alternative system to address such questions. Key to their ecological success, fungi present a broad and diverse range of phenotypic traits. Fungal cells can adopt many different shapes, often within a single species, providing them with great adaptive potential. Fungal cellular organizations span from unicellular forms to complex, macroscopic multicellularity, with multiple transitions to higher or lower levels of cellular complexity occurring throughout the evolutionary history of fungi. Similarly, fungal genomes are very diverse in their architecture. Deep changes in genome organization can occur very quickly, and these phenomena are known to mediate rapid adaptations to environmental changes. Finally, the biochemical complexity of fungi is huge, particularly with regard to their secondary metabolites, chemical products that mediate many aspects of fungal biology, including ecological interactions. Herein, we explore how the interplay of these cellular, genomic and metabolic traits mediates the emergence of complex phenotypes, and how this complexity is shaped throughout the evolutionary history of Fungi.
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Affiliation(s)
- Miguel A. Naranjo‐Ortiz
- Bioinformatics and Genomics Programme, Centre for Genomic Regulation (CRG)The Barcelona Institute of Science and TechnologyDr. Aiguader 88, Barcelona08003Spain
| | - Toni Gabaldón
- Bioinformatics and Genomics Programme, Centre for Genomic Regulation (CRG)The Barcelona Institute of Science and TechnologyDr. Aiguader 88, Barcelona08003Spain
- Department of Experimental Sciences, Universitat Pompeu Fabra (UPF)Dr. Aiguader 88, 08003BarcelonaSpain
- ICREAPg. Lluís Companys 23, 08010BarcelonaSpain
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Torres DE, Oggenfuss U, Croll D, Seidl MF. Genome evolution in fungal plant pathogens: looking beyond the two-speed genome model. FUNGAL BIOL REV 2020. [DOI: 10.1016/j.fbr.2020.07.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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An orphan protein of Fusarium graminearum modulates host immunity by mediating proteasomal degradation of TaSnRK1α. Nat Commun 2020; 11:4382. [PMID: 32873802 PMCID: PMC7462860 DOI: 10.1038/s41467-020-18240-y] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 08/06/2020] [Indexed: 02/06/2023] Open
Abstract
Fusarium graminearum is a causal agent of Fusarium head blight (FHB) and a deoxynivalenol (DON) producer. In this study, OSP24 is identified as an important virulence factor in systematic characterization of the 50 orphan secreted protein (OSP) genes of F. graminearum. Although dispensable for growth and initial penetration, OSP24 is important for infectious growth in wheat rachis tissues. OSP24 is specifically expressed during pathogenesis and its transient expression suppresses BAX- or INF1-induced cell death. Osp24 is translocated into plant cells and two of its 8 cysteine-residues are required for its function. Wheat SNF1-related kinase TaSnRK1α is identified as an Osp24-interacting protein and shows to be important for FHB resistance in TaSnRK1α-overexpressing or silencing transgenic plants. Osp24 accelerates the degradation of TaSnRK1α by facilitating its association with the ubiquitin-26S proteasome. Interestingly, TaSnRK1α also interacts with TaFROG, an orphan wheat protein induced by DON. TaFROG competes against Osp24 for binding with the same region of TaSnRKα and protects it from degradation. Overexpression of TaFROG stabilizes TaSnRK1α and increases FHB resistance. Taken together, Osp24 functions as a cytoplasmic effector by competing against TaFROG for binding with TaSnRK1α, demonstrating the counteracting roles of orphan proteins of both host and fungal pathogens during their interactions. Fusarium graminearum is a major fungal pathogen of cereals. Here the authors show that F. graminearum secretes an effector, Osp24, that induces degradation of the wheat TaSnRK1α kinase to promote disease while an orphan wheat protein, TaFROG1, can compete with Osp24 for binding to TaSnRK1α and protect it from degradation
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Feurtey A, Lorrain C, Croll D, Eschenbrenner C, Freitag M, Habig M, Haueisen J, Möller M, Schotanus K, Stukenbrock EH. Genome compartmentalization predates species divergence in the plant pathogen genus Zymoseptoria. BMC Genomics 2020; 21:588. [PMID: 32842972 PMCID: PMC7448473 DOI: 10.1186/s12864-020-06871-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 06/26/2020] [Indexed: 11/25/2022] Open
Abstract
Background Antagonistic co-evolution can drive rapid adaptation in pathogens and shape genome architecture. Comparative genome analyses of several fungal pathogens revealed highly variable genomes, for many species characterized by specific repeat-rich genome compartments with exceptionally high sequence variability. Dynamic genome structure may enable fast adaptation to host genetics. The wheat pathogen Zymoseptoria tritici with its highly variable genome, has emerged as a model organism to study genome evolution of plant pathogens. Here, we compared genomes of Z. tritici isolates and of sister species infecting wild grasses to address the evolution of genome composition and structure. Results Using long-read technology, we sequenced and assembled genomes of Z. ardabiliae, Z. brevis, Z. pseudotritici and Z. passerinii, together with two isolates of Z. tritici. We report a high extent of genome collinearity among Zymoseptoria species and high conservation of genomic, transcriptomic and epigenomic signatures of compartmentalization. We identify high gene content variability both within and between species. In addition, such variability is mainly limited to the accessory chromosomes and accessory compartments. Despite strong host specificity and non-overlapping host-range between species, predicted effectors are mainly shared among Zymoseptoria species, yet exhibiting a high level of presence-absence polymorphism within Z. tritici. Using in planta transcriptomic data from Z. tritici, we suggest different roles for the shared orthologs and for the accessory genes during infection of their hosts. Conclusion Despite previous reports of high genomic plasticity in Z. tritici, we describe here a high level of conservation in genomic, epigenomic and transcriptomic composition and structure across the genus Zymoseptoria. The compartmentalized genome allows the maintenance of a functional core genome co-occurring with a highly variable accessory genome.
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Affiliation(s)
- Alice Feurtey
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306, Plön, Germany.,Environmental Genomics, Christian-Albrechts University of Kiel, 24118, Kiel, Germany
| | - Cécile Lorrain
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306, Plön, Germany. .,Environmental Genomics, Christian-Albrechts University of Kiel, 24118, Kiel, Germany. .,INRA Centre Grand Est - Nancy, UMR 1136 INRA/Universite de Lorraine Interactions Arbres/Microorganismes, 54280, Champenoux, France.
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, 2000, Neuchâtel, Switzerland
| | - Christoph Eschenbrenner
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306, Plön, Germany.,Environmental Genomics, Christian-Albrechts University of Kiel, 24118, Kiel, Germany
| | - Michael Freitag
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, USA
| | - Michael Habig
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306, Plön, Germany.,Environmental Genomics, Christian-Albrechts University of Kiel, 24118, Kiel, Germany
| | - Janine Haueisen
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306, Plön, Germany.,Environmental Genomics, Christian-Albrechts University of Kiel, 24118, Kiel, Germany
| | - Mareike Möller
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306, Plön, Germany.,Environmental Genomics, Christian-Albrechts University of Kiel, 24118, Kiel, Germany.,Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, USA
| | - Klaas Schotanus
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306, Plön, Germany.,Environmental Genomics, Christian-Albrechts University of Kiel, 24118, Kiel, Germany.,Department of Molecular Genetics and Microbiology, Duke University, Duke University Medical Center, Durham, NC, 27710, USA
| | - Eva H Stukenbrock
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306, Plön, Germany.,Environmental Genomics, Christian-Albrechts University of Kiel, 24118, Kiel, Germany
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Rangel LI, Spanner RE, Ebert MK, Pethybridge SJ, Stukenbrock EH, de Jonge R, Secor GA, Bolton MD. Cercospora beticola: The intoxicating lifestyle of the leaf spot pathogen of sugar beet. MOLECULAR PLANT PATHOLOGY 2020; 21:1020-1041. [PMID: 32681599 PMCID: PMC7368123 DOI: 10.1111/mpp.12962] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 05/15/2020] [Accepted: 05/17/2020] [Indexed: 05/07/2023]
Abstract
Cercospora leaf spot, caused by the fungal pathogen Cercospora beticola, is the most destructive foliar disease of sugar beet worldwide. This review discusses C. beticola genetics, genomics, and biology and summarizes our current understanding of the molecular interactions that occur between C. beticola and its sugar beet host. We highlight the known virulence arsenal of C. beticola as well as its ability to overcome currently used disease management strategies. Finally, we discuss future prospects for the study and management of C. beticola infections in the context of newly employed molecular tools to uncover additional information regarding the biology of this pathogen. TAXONOMY Cercospora beticola Sacc.; Kingdom Fungi, Phylum Ascomycota, Class Dothideomycetes, Order Capnodiales, Family Mycosphaerellaceae, Genus Cercospora. HOST RANGE Well-known pathogen of sugar beet (Beta vulgaris subsp. vulgaris) and most species of the Beta genus. Reported as pathogenic on other members of the Chenopodiaceae (e.g., lamb's quarters, spinach) as well as members of the Acanthaceae (e.g., bear's breeches), Apiaceae (e.g., Apium), Asteraceae (e.g., chrysanthemum, lettuce, safflower), Brassicaceae (e.g., wild mustard), Malvaceae (e.g., Malva), Plumbaginaceae (e.g., Limonium), and Polygonaceae (e.g., broad-leaved dock) families. DISEASE SYMPTOMS Leaves infected with C. beticola exhibit circular lesions that are coloured tan to grey in the centre and are often delimited by tan-brown to reddish-purple rings. As disease progresses, spots can coalesce to form larger necrotic areas, causing severely infected leaves to wither and die. At the centre of these spots are black spore-bearing structures (pseudostromata). Older leaves often show symptoms first and younger leaves become infected as the disease progresses. MANAGEMENT Application of a mixture of fungicides with different modes of action is currently performed although elevated resistance has been documented in most employed fungicide classes. Breeding for high-yielding cultivars with improved host resistance is an ongoing effort and prudent cultural practices, such as crop rotation, weed host management, and cultivation to reduce infested residue levels, are widely used to manage disease. USEFUL WEBSITE: https://www.ncbi.nlm.nih.gov/genome/11237?genome_assembly_id=352037.
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Affiliation(s)
- Lorena I. Rangel
- Northern Crop Science LaboratoryU.S. Department of Agriculture ‐ Agricultural Research ServiceFargoNDUSA
| | - Rebecca E. Spanner
- Northern Crop Science LaboratoryU.S. Department of Agriculture ‐ Agricultural Research ServiceFargoNDUSA
- Department of Plant PathologyNorth Dakota State UniversityFargoNDUSA
| | - Malaika K. Ebert
- Northern Crop Science LaboratoryU.S. Department of Agriculture ‐ Agricultural Research ServiceFargoNDUSA
- Department of Plant PathologyNorth Dakota State UniversityFargoNDUSA
- Present address:
Department of Plant BiologyMichigan State UniversityEast LansingMIUSA
| | - Sarah J. Pethybridge
- Plant Pathology & Plant‐Microbe Biology SectionSchool of Integrative Plant ScienceCornell AgriTech at The New York State Agricultural Experiment StationCornell UniversityGenevaNYUSA
| | - Eva H. Stukenbrock
- Environmental Genomics GroupMax Planck Institute for Evolutionary BiologyPlönGermany
- Christian‐Albrechts University of KielKielGermany
| | - Ronnie de Jonge
- Department of Plant‐Microbe InteractionsUtrecht UniversityUtrechtNetherlands
| | - Gary A. Secor
- Department of Plant PathologyNorth Dakota State UniversityFargoNDUSA
| | - Melvin D. Bolton
- Northern Crop Science LaboratoryU.S. Department of Agriculture ‐ Agricultural Research ServiceFargoNDUSA
- Department of Plant PathologyNorth Dakota State UniversityFargoNDUSA
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Badet T, Croll D. The rise and fall of genes: origins and functions of plant pathogen pangenomes. CURRENT OPINION IN PLANT BIOLOGY 2020; 56:65-73. [PMID: 32480355 DOI: 10.1016/j.pbi.2020.04.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 04/14/2020] [Accepted: 04/18/2020] [Indexed: 06/11/2023]
Abstract
Plant pathogens can rapidly overcome resistance of their hosts by mutating key pathogenicity genes encoding for effectors. Pathogen adaptation is fuelled by extensive genetic variability in populations and different strains may not share the same set of genes. Recently, such an intra-specific variation in gene content became formalized as pangenomes distinguishing core genes (i.e. shared) and accessory genes (i.e. lineage or strain-specific). Across pathogens species, key effectors tend to be part of the rapidly evolving accessory genome. Here, we show how the construction and analysis of pathogen pangenomes provide deep insights into the dynamic host adaptation process. We also discuss how pangenomes should ideally be built and how geography, niche and lifestyle likely determine pangenome sizes.
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Affiliation(s)
- Thomas Badet
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Switzerland
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Switzerland.
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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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Hovhannisyan H, Saus E, Ksiezopolska E, Hinks Roberts AJ, Louis EJ, Gabaldón T. Integrative Omics Analysis Reveals a Limited Transcriptional Shock After Yeast Interspecies Hybridization. Front Genet 2020; 11:404. [PMID: 32457798 PMCID: PMC7221068 DOI: 10.3389/fgene.2020.00404] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 03/30/2020] [Indexed: 12/30/2022] Open
Abstract
The formation of interspecific hybrids results in the coexistence of two diverged genomes within the same nucleus. It has been hypothesized that negative epistatic interactions and regulatory interferences between the two sub-genomes may elicit a so-called genomic shock involving, among other alterations, broad transcriptional changes. To assess the magnitude of this shock in hybrid yeasts, we investigated the transcriptomic differences between a newly formed Saccharomyces cerevisiae × Saccharomyces uvarum diploid hybrid and its diploid parentals, which diverged ∼20 mya. RNA sequencing (RNA-Seq) based allele-specific expression (ASE) analysis indicated that gene expression changes in the hybrid genome are limited, with only ∼1–2% of genes significantly altering their expression with respect to a non-hybrid context. In comparison, a thermal shock altered six times more genes. Furthermore, differences in the expression between orthologous genes in the two parental species tended to be diminished for the corresponding homeologous genes in the hybrid. Finally, and consistent with the RNA-Seq results, we show a limited impact of hybridization on chromatin accessibility patterns, as assessed with assay for transposase-accessible chromatin using sequencing (ATAC-Seq). Overall, our results suggest a limited genomic shock in a newly formed yeast hybrid, which may explain the high frequency of successful hybridization in these organisms.
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Affiliation(s)
- Hrant Hovhannisyan
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain.,Department of Health and Life Sciences. Universitat Pompeu Fabra, Barcelona, Spain
| | - Ester Saus
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain.,Department of Health and Life Sciences. Universitat Pompeu Fabra, Barcelona, Spain
| | - Ewa Ksiezopolska
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain.,Department of Health and Life Sciences. Universitat Pompeu Fabra, Barcelona, Spain
| | - Alex J Hinks Roberts
- Centre for Genetic Architecture of Complex Traits, University of Leicester, Leicester, United Kingdom
| | - Edward J Louis
- Centre for Genetic Architecture of Complex Traits, University of Leicester, Leicester, United Kingdom
| | - Toni Gabaldón
- Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain.,Department of Health and Life Sciences. Universitat Pompeu Fabra, Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain
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31
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Feurtey A, Stevens DM, Stephan W, Stukenbrock EH. Interspecific Gene Exchange Introduces High Genetic Variability in Crop Pathogen. Genome Biol Evol 2020; 11:3095-3105. [PMID: 31603209 PMCID: PMC6836716 DOI: 10.1093/gbe/evz224] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/08/2019] [Indexed: 12/27/2022] Open
Abstract
Genome analyses have revealed a profound role of hybridization and introgression in the evolution of many eukaryote lineages, including fungi. The impact of recurrent introgression on fungal evolution however remains elusive. Here, we analyzed signatures of introgression along the genome of the fungal wheat pathogen Zymoseptoria tritici. We applied a comparative population genomics approach, including genome data from five Zymoseptoria species, to characterize the distribution and composition of introgressed regions representing segments with an exceptional haplotype pattern. These regions are found throughout the genome, comprising 5% of the total genome and overlapping with > 1,000 predicted genes. We performed window-based phylogenetic analyses along the genome to distinguish regions which have a monophyletic or nonmonophyletic origin with Z. tritici sequences. A majority of nonmonophyletic windows overlap with the highly variable regions suggesting that these originate from introgression. We verified that incongruent gene genealogies do not result from incomplete lineage sorting by comparing the observed and expected length distribution of haplotype blocks resulting from incomplete lineage sorting. Although protein-coding genes are not enriched in these regions, we identify 18 that encode putative virulence determinants. Moreover, we find an enrichment of transposable elements in these regions implying that hybridization may contribute to the horizontal spread of transposable elements. We detected a similar pattern in the closely related species Zymoseptoria ardabiliae, suggesting that hybridization is widespread among these closely related grass pathogens. Overall, our results demonstrate a significant impact of recurrent hybridization on overall genome evolution of this important wheat pathogen.
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Affiliation(s)
- Alice Feurtey
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, Plön, Germany.,Botanical Institute, Christian-Albrechts University of Kiel, Germany
| | - Danielle M Stevens
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, Plön, Germany.,Botanical Institute, Christian-Albrechts University of Kiel, Germany.,Department of Plant Pathology, University of California, Davis
| | - Wolfgang Stephan
- Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany
| | - Eva H Stukenbrock
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, Plön, Germany.,Botanical Institute, Christian-Albrechts University of Kiel, Germany
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Gu X, Ding J, Liu W, Yang X, Yao L, Gao X, Zhang M, Yang S, Wen J. Comparative genomics and association analysis identifies virulence genes of Cercospora sojina in soybean. BMC Genomics 2020; 21:172. [PMID: 32075575 PMCID: PMC7032006 DOI: 10.1186/s12864-020-6581-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 02/13/2020] [Indexed: 03/01/2023] Open
Abstract
BACKGROUND Recently, a new strain of Cercospora sojina (Race15) has been identified, which has caused the breakdown of resistance in most soybean cultivars in China. Despite this serious yield reduction, little is known about why this strain is more virulent than others. Therefore, we sequenced the Race15 genome and compared it to the Race1 genome sequence, as its virulence is significantly lower. We then re-sequenced 30 isolates of C. sojina from different regions to identifying differential virulence genes using genome-wide association analysis (GWAS). RESULTS The 40.12-Mb Race15 genome encodes 12,607 predicated genes and contains large numbers of gene clusters that have annotations in 11 different common databases. Comparative genomics revealed that although these two genomes had a large number of homologous genes, their genome structures have evolved to introduce 245 specific genes. The most important 5 candidate virulence genes were located on Contig 3 and Contig 1 and were mainly related to the regulation of metabolic mechanisms and the biosynthesis of bioactive metabolites, thereby putatively affecting fungi self-toxicity and reducing host resistance. Our study provides insight into the genomic basis of C. sojina pathogenicity and its infection mechanism, enabling future studies of this disease. CONCLUSIONS Via GWAS, we identified five candidate genes using three different methods, and these candidate genes are speculated to be related to metabolic mechanisms and the biosynthesis of bioactive metabolites. Meanwhile, Race15 specific genes may be linked with high virulence. The genes highly prevalent in virulent isolates should also be proposed as candidates, even though they were not found in our SNP analysis. Future work should focus on using a larger sample size to confirm and refine candidate gene identifications and should study the functional roles of these candidates, in order to investigate their potential roles in C. sojina pathogenicity.
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Affiliation(s)
- Xin Gu
- Department of Plant Protection, College of Agriculture, Northeast Agricultural University, Harbin, China
- Jiamusi Branch of Heilongjiang Academy of Agricultural Sciences, Jiamusi, China
| | - Junjie Ding
- Jiamusi Branch of Heilongjiang Academy of Agricultural Sciences, Jiamusi, China
| | - Wei Liu
- Jiamusi Branch of Heilongjiang Academy of Agricultural Sciences, Jiamusi, China
| | - Xiaohe Yang
- Jiamusi Branch of Heilongjiang Academy of Agricultural Sciences, Jiamusi, China
| | - Liangliang Yao
- Jiamusi Branch of Heilongjiang Academy of Agricultural Sciences, Jiamusi, China
| | - Xuedong Gao
- Jiamusi Branch of Heilongjiang Academy of Agricultural Sciences, Jiamusi, China
| | - Maoming Zhang
- Jiamusi Branch of Heilongjiang Academy of Agricultural Sciences, Jiamusi, China
| | - Shuai Yang
- Potato Research Institute, Heilongjiang Academy of Agricultural Sciences, Harbin, 150086, China
| | - Jingzhi Wen
- Department of Plant Protection, College of Agriculture, Northeast Agricultural University, Harbin, China.
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33
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Badet T, Oggenfuss U, Abraham L, McDonald BA, Croll D. A 19-isolate reference-quality global pangenome for the fungal wheat pathogen Zymoseptoria tritici. BMC Biol 2020; 18:12. [PMID: 32046716 PMCID: PMC7014611 DOI: 10.1186/s12915-020-0744-3] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 01/27/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND The gene content of a species largely governs its ecological interactions and adaptive potential. A species is therefore defined by both core genes shared between all individuals and accessory genes segregating presence-absence variation. There is growing evidence that eukaryotes, similar to bacteria, show intra-specific variability in gene content. However, it remains largely unknown how functionally relevant such a pangenome structure is for eukaryotes and what mechanisms underlie the emergence of highly polymorphic genome structures. RESULTS Here, we establish a reference-quality pangenome of a fungal pathogen of wheat based on 19 complete genomes from isolates sampled across six continents. Zymoseptoria tritici causes substantial worldwide losses to wheat production due to rapidly evolved tolerance to fungicides and evasion of host resistance. We performed transcriptome-assisted annotations of each genome to construct a global pangenome. Major chromosomal rearrangements are segregating within the species and underlie extensive gene presence-absence variation. Conserved orthogroups account for only ~ 60% of the species pangenome. Investigating gene functions, we find that the accessory genome is enriched for pathogenesis-related functions and encodes genes involved in metabolite production, host tissue degradation and manipulation of the immune system. De novo transposon annotation of the 19 complete genomes shows that the highly diverse chromosomal structure is tightly associated with transposable element content. Furthermore, transposable element expansions likely underlie recent genome expansions within the species. CONCLUSIONS Taken together, our work establishes a highly complex eukaryotic pangenome providing an unprecedented toolbox to study how pangenome structure impacts crop-pathogen interactions.
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Affiliation(s)
- Thomas Badet
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Ursula Oggenfuss
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Leen Abraham
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Bruce A McDonald
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland.
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Badet T, Oggenfuss U, Abraham L, McDonald BA, Croll D. A 19-isolate reference-quality global pangenome for the fungal wheat pathogen Zymoseptoria tritici. BMC Biol 2020; 18:12. [PMID: 32046716 DOI: 10.1101/803098] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 01/27/2020] [Indexed: 05/26/2023] Open
Abstract
BACKGROUND The gene content of a species largely governs its ecological interactions and adaptive potential. A species is therefore defined by both core genes shared between all individuals and accessory genes segregating presence-absence variation. There is growing evidence that eukaryotes, similar to bacteria, show intra-specific variability in gene content. However, it remains largely unknown how functionally relevant such a pangenome structure is for eukaryotes and what mechanisms underlie the emergence of highly polymorphic genome structures. RESULTS Here, we establish a reference-quality pangenome of a fungal pathogen of wheat based on 19 complete genomes from isolates sampled across six continents. Zymoseptoria tritici causes substantial worldwide losses to wheat production due to rapidly evolved tolerance to fungicides and evasion of host resistance. We performed transcriptome-assisted annotations of each genome to construct a global pangenome. Major chromosomal rearrangements are segregating within the species and underlie extensive gene presence-absence variation. Conserved orthogroups account for only ~ 60% of the species pangenome. Investigating gene functions, we find that the accessory genome is enriched for pathogenesis-related functions and encodes genes involved in metabolite production, host tissue degradation and manipulation of the immune system. De novo transposon annotation of the 19 complete genomes shows that the highly diverse chromosomal structure is tightly associated with transposable element content. Furthermore, transposable element expansions likely underlie recent genome expansions within the species. CONCLUSIONS Taken together, our work establishes a highly complex eukaryotic pangenome providing an unprecedented toolbox to study how pangenome structure impacts crop-pathogen interactions.
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Affiliation(s)
- Thomas Badet
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Ursula Oggenfuss
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Leen Abraham
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Bruce A McDonald
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland.
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Fouché S, Badet T, Oggenfuss U, Plissonneau C, Francisco CS, Croll D. Stress-Driven Transposable Element De-repression Dynamics and Virulence Evolution in a Fungal Pathogen. Mol Biol Evol 2020; 37:221-239. [PMID: 31553475 DOI: 10.1093/molbev/msz216] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Transposable elements (TEs) are drivers of genome evolution and affect the expression landscape of the host genome. Stress is a major factor inducing TE activity; however, the regulatory mechanisms underlying de-repression are poorly understood. Plant pathogens are excellent models to dissect the impact of stress on TEs. The process of plant infection induces stress for the pathogen, and virulence factors (i.e., effectors) located in TE-rich regions become expressed. To dissect TE de-repression dynamics and contributions to virulence, we analyzed the TE expression landscape of four strains of the major wheat pathogen Zymoseptoria tritici. We experimentally exposed strains to nutrient starvation and host infection stress. Contrary to expectations, we show that the two distinct conditions induce the expression of different sets of TEs. In particular, the most highly expressed TEs, including miniature inverted-repeat transposable element and long terminal repeat-Gypsy element, show highly distinct de-repression across stress conditions. Both the genomic context of TEs and the genetic background stress (i.e., different strains harboring the same TEs) were major predictors of de-repression under stress. Gene expression profiles under stress varied significantly depending on the proximity to the closest TEs and genomic defenses against TEs were largely ineffective to prevent de-repression. Next, we analyzed the locus encoding the Avr3D1 effector. We show that the insertion and subsequent silencing of TEs in close proximity likely contributed to reduced expression and virulence on a specific wheat cultivar. The complexity of TE responsiveness to stress across genetic backgrounds and genomic locations demonstrates substantial intraspecific genetic variation to control TEs with consequences for virulence.
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Affiliation(s)
- Simone Fouché
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland.,Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Thomas Badet
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Ursula Oggenfuss
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Clémence Plissonneau
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | | | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
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Ma X, Wiedmer J, Palma-Guerrero J. Small RNA Bidirectional Crosstalk During the Interaction Between Wheat and Zymoseptoria tritici. FRONTIERS IN PLANT SCIENCE 2020; 10:1669. [PMID: 31969895 PMCID: PMC6960233 DOI: 10.3389/fpls.2019.01669] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 11/27/2019] [Indexed: 05/21/2023]
Abstract
Cross-kingdom RNA interference (RNAi) has been shown to play important roles during plant-pathogen interactions, and both plants and pathogens can use small RNAs (sRNAs) to silence genes in each other. This bidirectional cross-kingdom RNAi was still unexplored in the wheat-Zymoseptoria tritici pathosystem. Here, we performed a detailed analysis of the sRNA bidirectional crosstalk between wheat and Z. tritici. Using a combination of small RNA sequencing (sRNA-seq) and microRNA sequencing (mRNA-seq), we were able to identify known and novel sRNAs and study their expression and their action on putative targets in both wheat and Z. tritici. We predicted the target genes of all the sRNAs in either wheat or Z. tritici transcriptome and used degradome analysis to validate the cleavage of these gene transcripts. We could not find any clear evidence of a cross-kingdom RNAi acting by mRNA cleavage in this pathosystem. We also found that the fungal sRNA enrichment was lower in planta than during in vitro growth, probably due to the lower expression of the only Dicer gene of the fungus during plant infection. Our results support the recent finding that Z. tritici sRNAs cannot play important roles during wheat infection. However, we also found that the fungal infection induced wheat sRNAs regulating the expression of specific wheat genes, including auxin-related genes, as an immune response. These results indicate a role of sRNAs in the regulation of wheat defenses during Z. tritici infection. Our findings contribute to improve our understanding of the interactions between wheat and Z. tritici.
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Affiliation(s)
- Xin Ma
- Plant Pathology, Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
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Brennan CJ, Zhou B, Benbow HR, Ajaz S, Karki SJ, Hehir JG, O’Driscoll A, Feechan A, Mullins E, Doohan FM. Taxonomically Restricted Wheat Genes Interact With Small Secreted Fungal Proteins and Enhance Resistance to Septoria Tritici Blotch Disease. FRONTIERS IN PLANT SCIENCE 2020; 11:433. [PMID: 32477375 PMCID: PMC7236048 DOI: 10.3389/fpls.2020.00433] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 03/24/2020] [Indexed: 05/12/2023]
Abstract
Understanding the nuances of host/pathogen interactions are paramount if we wish to effectively control cereal diseases. In the case of the wheat/Zymoseptoria tritici interaction that leads to Septoria tritici blotch (STB) disease, a 10,000-year-old conflict has led to considerable armaments being developed on both sides which are not reflected in conventional model systems. Taxonomically restricted genes (TRGs) have evolved in wheat to better allow it to cope with stress caused by fungal pathogens, and Z. tritici has evolved specialized effectors which allow it to manipulate its' host. A microarray focused on the latent phase response of a resistant wheat cultivar (cv. Stigg) and susceptible wheat cultivar (cv. Gallant) to Z. tritici infection was mined for TRGs within the Poaceae. From this analysis, we identified two TRGs that were significantly upregulated in response to Z. tritici infection, Septoria-responsive TRG6 and 7 (TaSRTRG6 and TaSRTRG7). Virus induced silencing of these genes resulted in an increased susceptibility to STB disease in cvs. Gallant and Stigg, and significantly so in the latter (2.5-fold increase in STB disease). In silico and localization studies categorized TaSRTRG6 as a secreted protein and TaSRTRG7 as an intracellular protein. Yeast two-hybrid analysis and biofluorescent complementation studies demonstrated that both TaSRTRG6 and TaSRTRG7 can interact with small proteins secreted by Z. tritici (potential effector candidates). Thus we conclude that TRGs are an important part of the wheat-Z. tritici co-evolution story and potential candidates for modulating STB resistance.
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Affiliation(s)
- Ciarán J. Brennan
- UCD School of Biology and Environmental Science and UCD Earth Institute, UCD O’Brien Centre for Science (East), University College Dublin, Belfield, Ireland
| | - Binbin Zhou
- UCD School of Biology and Environmental Science and UCD Earth Institute, UCD O’Brien Centre for Science (East), University College Dublin, Belfield, Ireland
| | - Harriet R. Benbow
- UCD School of Biology and Environmental Science and UCD Earth Institute, UCD O’Brien Centre for Science (East), University College Dublin, Belfield, Ireland
| | - Sobia Ajaz
- UCD School of Biology and Environmental Science and UCD Earth Institute, UCD O’Brien Centre for Science (East), University College Dublin, Belfield, Ireland
| | - Sujit J. Karki
- School of Agriculture and Food Science, University College Dublin, Belfield, Ireland
| | | | | | - Angela Feechan
- School of Agriculture and Food Science, University College Dublin, Belfield, Ireland
| | - Ewen Mullins
- Department of Crop Science, Teagasc, Carlow, Ireland
| | - Fiona M. Doohan
- UCD School of Biology and Environmental Science and UCD Earth Institute, UCD O’Brien Centre for Science (East), University College Dublin, Belfield, Ireland
- *Correspondence: Fiona M. Doohan,
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Cause and Effectors: Whole-Genome Comparisons Reveal Shared but Rapidly Evolving Effector Sets among Host-Specific Plant-Castrating Fungi. mBio 2019; 10:mBio.02391-19. [PMID: 31690676 PMCID: PMC6831777 DOI: 10.1128/mbio.02391-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Plant pathogens use molecular weapons to successfully infect their hosts, secreting a large portfolio of various proteins and enzymes. Different plant species are often parasitized by host-specific pathogens; however, it is still unclear whether the molecular basis of such host specialization involves species-specific weapons or different variants of the same weapons. We therefore compared the genes encoding secreted proteins in three plant-castrating pathogens parasitizing different host plants, producing their spores in plant anthers by replacing pollen. We validated our predictions for secretion signals for some genes and checked that our predicted secreted proteins were often highly expressed during plant infection. While we found few species-specific secreted proteins, numerous genes encoding secreted proteins showed signs of rapid evolution and of natural selection. Our study thus found that most changes among closely related host-specific pathogens involved rapid adaptive changes in shared molecular weapons rather than innovations for new weapons. Plant pathogens utilize a portfolio of secreted effectors to successfully infect and manipulate their hosts. It is, however, still unclear whether changes in secretomes leading to host specialization involve mostly effector gene gains/losses or changes in their sequences. To test these hypotheses, we compared the secretomes of three host-specific castrating anther smut fungi (Microbotryum), two being sister species. To address within-species evolution, which might involve coevolution and local adaptation, we compared the secretomes of strains from differentiated populations. We experimentally validated a subset of signal peptides. Secretomes ranged from 321 to 445 predicted secreted proteins (SPs), including a few species-specific proteins (42 to 75), and limited copy number variation, i.e., little gene family expansion or reduction. Between 52% and 68% of the SPs did not match any Pfam domain, a percentage that reached 80% for the small secreted proteins, indicating rapid evolution. In comparison to background genes, we indeed found SPs to be more differentiated among species and strains, more often under positive selection, and highly expressed in planta; repeat-induced point mutations (RIPs) had no role in effector diversification, as SPs were not closer to transposable elements than background genes and were not more RIP affected. Our study thus identified both conserved core proteins, likely required for the pathogenic life cycle of all Microbotryum species, and proteins that were species specific or evolving under positive selection; these proteins may be involved in host specialization and/or coevolution. Most changes among closely related host-specific pathogens, however, involved rapid changes in sequences rather than gene gains/losses.
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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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40
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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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Mohd-Assaad N, McDonald BA, Croll D. The emergence of the multi-species NIP1 effector in Rhynchosporium was accompanied by high rates of gene duplications and losses. Environ Microbiol 2019; 21:2677-2695. [PMID: 30838748 DOI: 10.1111/1462-2920.14583] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 02/23/2019] [Accepted: 03/04/2019] [Indexed: 01/28/2023]
Abstract
Plant pathogens secrete effector proteins to manipulate the host and facilitate infection. Cognate hosts trigger strong defence responses upon detection of these effectors. Consequently, pathogens and hosts undergo rapid coevolutionary arms races driven by adaptive evolution of effectors and receptors. Because of their high rate of turnover, most effectors are thought to be species-specific and the evolutionary trajectories are poorly understood. Here, we investigate the necrosis-inducing protein 1 (NIP1) effector in the multihost pathogen genus Rhynchosporium. We retraced the evolutionary history of the NIP1 locus using whole-genome assemblies of 146 strains covering four closely related species. NIP1 orthologues were present in all species but the locus consistently segregated presence-absence polymorphisms suggesting long-term balancing selection. We also identified previously unknown paralogues of NIP1 that were shared among multiple species and showed substantial copy-number variation within R. commune. The NIP1A paralogue was under significant positive selection suggesting that NIP1A is the dominant effector variant coevolving with host immune receptors. Consistent with this prediction, we found that copy number variation at NIP1A had a stronger effect on virulence than NIP1B. Our analyses unravelled the origins and diversification mechanisms of a pathogen effector family shedding light on how pathogens gain adaptive genetic variation.
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Affiliation(s)
- Norfarhan Mohd-Assaad
- Plant Pathology, Institute of Integrative Biology, ETH, Zurich, 8092 Zurich, Switzerland.,School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
| | - Bruce A McDonald
- Plant Pathology, Institute of Integrative Biology, ETH, Zurich, 8092 Zurich, Switzerland
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, 2000 Neuchâtel, Switzerland
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Mitotic Recombination and Rapid Genome Evolution in the Invasive Forest Pathogen Phytophthora ramorum. mBio 2019; 10:mBio.02452-18. [PMID: 30862749 PMCID: PMC6414701 DOI: 10.1128/mbio.02452-18] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Alien species are often successful invaders in new environments, despite the introduction of a few isolates with a reduced genetic pool. This is called the genetic paradox of invasion. We found two mechanisms by which the invasive forest pathogen causing sudden oak and sudden larch death can evolve. Extensive mitotic recombination producing runs of homozygosity generates genotypic diversity even in the absence of sexual reproduction, and rapid turnover of genes in the non-core, or nonessential portion of genome not shared by all isolates, allows pathogenicity genes to evolve rapidly or be eliminated while retaining essential genes. Mitotic recombination events occur in genomic hot spots, resulting in similar ROH patterns in different isolates or groups; one ROH, independently generated in two different groups, was enriched in pathogenicity genes and may be a target for selection. This provides important insights into the evolution of invasive alien pathogens and their potential for adaptation and future persistence. Invasive alien species often have reduced genetic diversity and must adapt to new environments. Given the success of many invasions, this is sometimes called the genetic paradox of invasion. Phytophthora ramorum is invasive, limited to asexual reproduction within four lineages, and presumed clonal. It is responsible for sudden oak death in the United States, sudden larch death in Europe, and ramorum blight in North America and Europe. We sequenced the genomes of 107 isolates to determine how this pathogen can overcome the invasion paradox. Mitotic recombination (MR) associated with transposons and low gene density has generated runs of homozygosity (ROH) affecting 2,698 genes, resulting in novel genotypic diversity within the lineages. One ROH enriched in effectors was fixed in the NA1 lineage. An independent ROH affected the same scaffold in the EU1 lineage, suggesting an MR hot spot and a selection target. Differences in host infection between EU1 isolates with and without the ROH suggest that they may differ in aggressiveness. Non-core regions (not shared by all lineages) had signatures of accelerated evolution and were enriched in putative pathogenicity genes and transposons. There was a striking pattern of gene loss, including all effectors, in the non-core EU2 genome. Positive selection was observed in 8.0% of RxLR and 18.8% of Crinkler effector genes compared with 0.9% of the core eukaryotic gene set. We conclude that the P. ramorum lineages are diverging via a rapidly evolving non-core genome and that the invasive asexual lineages are not clonal, but display genotypic diversity caused by MR.
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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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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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45
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Chen ECH, Morin E, Beaudet D, Noel J, Yildirir G, Ndikumana S, Charron P, St-Onge C, Giorgi J, Krüger M, Marton T, Ropars J, Grigoriev IV, Hainaut M, Henrissat B, Roux C, Martin F, Corradi N. High intraspecific genome diversity in the model arbuscular mycorrhizal symbiont Rhizophagus irregularis. THE NEW PHYTOLOGIST 2018; 220:1161-1171. [PMID: 29355972 DOI: 10.1111/nph.14989] [Citation(s) in RCA: 126] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 12/03/2017] [Indexed: 05/20/2023]
Abstract
Arbuscular mycorrhizal fungi (AMF) are known to improve plant fitness through the establishment of mycorrhizal symbioses. Genetic and phenotypic variations among closely related AMF isolates can significantly affect plant growth, but the genomic changes underlying this variability are unclear. To address this issue, we improved the genome assembly and gene annotation of the model strain Rhizophagus irregularis DAOM197198, and compared its gene content with five isolates of R. irregularis sampled in the same field. All isolates harbor striking genome variations, with large numbers of isolate-specific genes, gene family expansions, and evidence of interisolate genetic exchange. The observed variability affects all gene ontology terms and PFAM protein domains, as well as putative mycorrhiza-induced small secreted effector-like proteins and other symbiosis differentially expressed genes. High variability is also found in active transposable elements. Overall, these findings indicate a substantial divergence in the functioning capacity of isolates harvested from the same field, and thus their genetic potential for adaptation to biotic and abiotic changes. Our data also provide a first glimpse into the genome diversity that resides within natural populations of these symbionts, and open avenues for future analyses of plant-AMF interactions that link AMF genome variation with plant phenotype and fitness.
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Affiliation(s)
- Eric C H Chen
- Department of Biology, University of Ottawa, Ottawa, ON, K1N9A7, Canada
| | - Emmanuelle Morin
- Institut National de la Recherche Agronomique (INRA), Unité Mixte de Recherche 1136 Interactions Arbres/Microorganismes, Laboratoire D'excellence Recherches Avancées sur la Biologie de l'Arbre et les Ecosystèmes Forestiers (ARBRE), Centre INRA-Grand Est-Nancy, Champenoux, 54280, France
| | - Denis Beaudet
- Department of Biology, University of Ottawa, Ottawa, ON, K1N9A7, Canada
| | - Jessica Noel
- Department of Biology, University of Ottawa, Ottawa, ON, K1N9A7, Canada
| | - Gokalp Yildirir
- Department of Biology, University of Ottawa, Ottawa, ON, K1N9A7, Canada
| | - Steve Ndikumana
- Department of Biology, University of Ottawa, Ottawa, ON, K1N9A7, Canada
| | - Philippe Charron
- Department of Biology, University of Ottawa, Ottawa, ON, K1N9A7, Canada
| | - Camille St-Onge
- Department of Biology, University of Ottawa, Ottawa, ON, K1N9A7, Canada
| | - John Giorgi
- Department of Biology, University of Ottawa, Ottawa, ON, K1N9A7, Canada
| | - Manuela Krüger
- Department of Biology, University of Ottawa, Ottawa, ON, K1N9A7, Canada
| | - Timea Marton
- Department of Biology, University of Ottawa, Ottawa, ON, K1N9A7, Canada
| | - Jeanne Ropars
- Department of Biology, University of Ottawa, Ottawa, ON, K1N9A7, Canada
| | - Igor V Grigoriev
- US Department of Energy Joint Genome Institute (JGI), Walnut Creek, CA, 94598, USA
| | - Matthieu Hainaut
- Architecture et Fonction des Macromolécules Biologiques, CNRS, Aix-Marseille Université, Marseille, 13288, France
- INRA, USC 1408 AFMB, Marseille, F-13288, France
| | - Bernard Henrissat
- Architecture et Fonction des Macromolécules Biologiques, CNRS, Aix-Marseille Université, Marseille, 13288, France
- INRA, USC 1408 AFMB, Marseille, F-13288, France
- Department of Biological Sciences, King Abdulaziz University, Jeddah, 21589, Saudi Arabia
| | - Christophe Roux
- Laboratoire de Recherche en Sciences Végétales, UPS, CNRS 24 Chemin de Borde Rouge-Auzeville, Université de Toulouse, Castanet-Tolosan, 31326, France
| | - Francis Martin
- Institut National de la Recherche Agronomique (INRA), Unité Mixte de Recherche 1136 Interactions Arbres/Microorganismes, Laboratoire D'excellence Recherches Avancées sur la Biologie de l'Arbre et les Ecosystèmes Forestiers (ARBRE), Centre INRA-Grand Est-Nancy, Champenoux, 54280, France
| | - Nicolas Corradi
- Department of Biology, University of Ottawa, Ottawa, ON, K1N9A7, Canada
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46
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Bioinformatic prediction of plant–pathogenicity effector proteins of fungi. Curr Opin Microbiol 2018; 46:43-49. [DOI: 10.1016/j.mib.2018.01.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 01/16/2018] [Accepted: 01/31/2018] [Indexed: 12/12/2022]
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47
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Mathieu S, Cusant L, Roux C, Corradi N. Arbuscular mycorrhizal fungi: intraspecific diversity and pangenomes. THE NEW PHYTOLOGIST 2018; 220:1129-1134. [PMID: 29949657 DOI: 10.1111/nph.15275] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 05/21/2018] [Indexed: 06/08/2023]
Abstract
Contents Summary 1129 I. Introduction 1129 II. Intraspecific phenotypic variation and the plant host 1130 III. High inter-isolate genetic diversity in model AMF 1130 IV. Genome diversity within the model AM fungus Rhizophagus irregularis 1131 V. Pangenomes and the future of AMF ecological genomics 1131 Acknowledgements 1133 References 1133 SUMMARY: Arbuscular mycorrhizal fungi (AMF) are ubiquitous plant symbionts with an intriguing population biology. Conspecific AMF strains can vary substantially at the genetic and phenotypic levels, leading to direct and quantifiable variation in plant growth. Recent studies have shown that high intraspecific diversity is very common in AMF, and not only found in model species. Studies have also revealed how the phenotype of conspecific isolates varies depending on the plant host, highlighting the functional relevance of intraspecific phenotypic plasticity for the AMF ecology and mycorrhizal symbiosis. Recent work has also demonstrated that conspecific isolates of the model AMF Rhizophagus irregularis harbor large and highly variable pangenomes, highlighting the potential role of intraspecific genome diversity for the ecological adaptation of these symbionts.
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Affiliation(s)
- Stephanie Mathieu
- Department of Biology, University of Ottawa, Ottawa, ON, K1N 6N5, Canada
| | - Loïc Cusant
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, UPS, CNRS 24 Chemin de Borde Rouge-Auzeville, Castanet-Tolosan, France
| | - Christophe Roux
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, UPS, CNRS 24 Chemin de Borde Rouge-Auzeville, Castanet-Tolosan, France
| | - Nicolas Corradi
- Department of Biology, University of Ottawa, Ottawa, ON, K1N 6N5, Canada
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48
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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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49
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Syme RA, Tan KC, Rybak K, Friesen TL, McDonald BA, Oliver RP, Hane JK. Pan-Parastagonospora Comparative Genome Analysis-Effector Prediction and Genome Evolution. Genome Biol Evol 2018; 10:2443-2457. [PMID: 30184068 PMCID: PMC6152946 DOI: 10.1093/gbe/evy192] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2018] [Indexed: 01/01/2023] Open
Abstract
We report a fungal pan-genome study involving Parastagonospora spp., including 21 isolates of the wheat (Triticum aestivum) pathogen Parastagonospora nodorum, 10 of the grass-infecting Parastagonospora avenae, and 2 of a closely related undefined sister species. We observed substantial variation in the distribution of polymorphisms across the pan-genome, including repeat-induced point mutations, diversifying selection and gene gains and losses. We also discovered chromosome-scale inter and intraspecific presence/absence variation of some sequences, suggesting the occurrence of one or more accessory chromosomes or regions that may play a role in host-pathogen interactions. The presence of known pathogenicity effector loci SnToxA, SnTox1, and SnTox3 varied substantially among isolates. Three P. nodorum isolates lacked functional versions for all three loci, whereas three P. avenae isolates carried one or both of the SnTox1 and SnTox3 genes, indicating previously unrecognized potential for discovering additional effectors in the P. nodorum-wheat pathosystem. We utilized the pan-genomic comparative analysis to improve the prediction of pathogenicity effector candidates, recovering the three confirmed effectors among our top-ranked candidates. We propose applying this pan-genomic approach to identify the effector repertoire involved in other host-microbe interactions involving necrotrophic pathogens in the Pezizomycotina.
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Affiliation(s)
- Robert A Syme
- Centre for Crop & Disease Management, School of Molecular & Life Sciences, Curtin University, Bentley, Western Australia, Australia
| | - Kar-Chun Tan
- Centre for Crop & Disease Management, School of Molecular & Life Sciences, Curtin University, Bentley, Western Australia, Australia
| | - Kasia Rybak
- Centre for Crop & Disease Management, School of Molecular & Life Sciences, Curtin University, Bentley, Western Australia, Australia
| | - Timothy L Friesen
- Cereal Crops Research Unit, USDA-ARS Red River Valley Agricultural Research Center, Fargo, North Dakota
| | - Bruce A McDonald
- Plant Pathology Group, Institute of Integrative Biology, Swiss Federal Institute of Technology (ETH), Zurich, Switzerland
| | - Richard P Oliver
- Centre for Crop & Disease Management, School of Molecular & Life Sciences, Curtin University, Bentley, Western Australia, Australia
| | - James K Hane
- Centre for Crop & Disease Management, School of Molecular & Life Sciences, Curtin University, Bentley, Western Australia, Australia
- Curtin Institute for Computation, Curtin University, Bentley, Western Australia, Australia
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50
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Sánchez-Vallet A, Fouché S, Fudal I, Hartmann FE, Soyer JL, Tellier A, Croll D. The Genome Biology of Effector Gene Evolution in Filamentous Plant Pathogens. ANNUAL REVIEW OF PHYTOPATHOLOGY 2018; 56:21-40. [PMID: 29768136 DOI: 10.1146/annurev-phyto-080516-035303] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Filamentous pathogens, including fungi and oomycetes, pose major threats to global food security. Crop pathogens cause damage by secreting effectors that manipulate the host to the pathogen's advantage. Genes encoding such effectors are among the most rapidly evolving genes in pathogen genomes. Here, we review how the major characteristics of the emergence, function, and regulation of effector genes are tightly linked to the genomic compartments where these genes are located in pathogen genomes. The presence of repetitive elements in these compartments is associated with elevated rates of point mutations and sequence rearrangements with a major impact on effector diversification. The expression of many effectors converges on an epigenetic control mediated by the presence of repetitive elements. Population genomics analyses showed that rapidly evolving pathogens show high rates of turnover at effector loci and display a mosaic in effector presence-absence polymorphism among strains. We conclude that effective pathogen containment strategies require a thorough understanding of the effector genome biology and the pathogen's potential for rapid adaptation.
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Affiliation(s)
- Andrea Sánchez-Vallet
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, 8092 Zürich, Switzerland
| | - Simone Fouché
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, 8092 Zürich, Switzerland
| | - Isabelle Fudal
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, 78850 Thiverval-Grignon, France
| | - Fanny E Hartmann
- Ecologie Systématique Evolution, AgroParisTech, Université Paris-Sud, CNRS, Université Paris-Saclay, 91400 Orsay, France
| | - Jessica L Soyer
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, 78850 Thiverval-Grignon, France
| | - Aurélien Tellier
- Section of Population Genetics, Technical University of Munich, 85354 Freising, Germany
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, 2000 Neuchâtel, Switzerland;
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