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Guo J, Shi G, Islam MM, Kariyawasam G, Moolhuijzen P, See PT, Zhong S, Aboukhaddour R, Faris JD, Friesen T, Liu Z. Identification of a novel genetic locus conferring virulence in the wheat tan spot pathogen Pyrenophora tritici-repentis. Fungal Genet Biol 2025; 179:104002. [PMID: 40383413 DOI: 10.1016/j.fgb.2025.104002] [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] [Received: 03/09/2025] [Revised: 05/12/2025] [Accepted: 05/13/2025] [Indexed: 05/20/2025]
Abstract
The ascomycete Pyrenophora tritici-repentis (Ptr) is the causal agent of tan spot, a common and economically important wheat disease worldwide. Three necrotrophic effectors (NEs), known as Ptr ToxA, Ptr ToxB, and Ptr ToxC, have been identified from the fungal pathogen as major virulence factors. The race 2 isolate 86-124 which produces Ptr ToxA is capable of causing disease on wheat lines that is insensitive to Ptr ToxA, suggesting the use of additional NEs during the infection. To identify new NE gene(s) from 86-124, we developed a biparental fungal population from a cross between this isolate and the race 5 isolate DW5 using genetically modified heterothallic strains. The fungal population was genotyped with SNP and SSR markers as well as the ToxA gene, the mating type genes, and six ToxB loci. Each progeny was phenotyped onto the hard red spring wheat line CDC-Osler, which is insensitive to both Ptr ToxA and Ptr ToxB, but is highly susceptible to 86-124. The constructed genetic map consisted of 11 linkage groups that corresponded to the 11 chromosomes (chr) of the Ptr reference genome. ToxA and mating type genes mapped to the expected positions. Five of the six ToxB copies were tightly linked, residing at the distal end of chr 11, while the sixth copy was localized to the distal end of chr 5. Composite interval mapping revealed a major QTL on the distal end of chr 2 conferring virulence toward CDC-Osler by 86-124. This locus was designated as VirOsler1. Genomic sequence alignment at the locus showed a region of approximately 900 kb at the end of chr 2 absent in DW5. The identification of VirOsler1 locus provides clear evidence that the wheat tan spot pathogen uses additional virulence factors that interact with unidentified host factors for disease susceptibility.
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Affiliation(s)
- Jingwei Guo
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58102, USA
| | - Gongjun Shi
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58102, USA
| | - Md Mukul Islam
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58102, USA
| | - Gayan Kariyawasam
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58102, USA; Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, TN 37996, USA
| | - Paula Moolhuijzen
- Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Bentley, WA 6102, Australia
| | - Pao-Theen See
- Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Bentley, WA 6102, Australia
| | - Shaobin Zhong
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58102, USA; USDA-ARS Cereal Disease Laboratory, St. Paul, MN 55108, USA
| | - Reem Aboukhaddour
- Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, Lethbridge, AB T1J 4B1, Canada
| | - Justin D Faris
- USDA-ARS Cereal Crops Research Unit, Edward T. Schafer Agricultural Research Center, Fargo, ND 58102, USA
| | - Timothy Friesen
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58102, USA; USDA-ARS Cereal Crops Research Unit, Edward T. Schafer Agricultural Research Center, Fargo, ND 58102, USA
| | - Zhaohui Liu
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58102, USA.
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2
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Oggenfuss U, Todd RT, Soisangwan N, Kemp B, Guyer A, Beach A, Selmecki A. Candida albicans isolates contain frequent heterozygous structural variants and transposable elements within genes and centromeres. Genome Res 2025; 35:824-838. [PMID: 39438112 PMCID: PMC12047244 DOI: 10.1101/gr.279301.124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2024] [Accepted: 10/21/2024] [Indexed: 10/25/2024]
Abstract
The human fungal pathogen Candida albicans poses a significant burden on global health, causing high rates of mortality and antifungal drug resistance. C. albicans is a heterozygous diploid organism that reproduces asexually. Structural variants (SVs) are an important source of genomic rearrangement, particularly in species that lack sexual recombination. To comprehensively investigate SVs across clinical isolates of C. albicans, we conducted long-read sequencing and genome-wide SV analysis in three distantly related clinical isolates. Our work includes a new, comprehensive analysis of transposable element (TE) composition, location, and diversity. SVs and TEs are frequently close to coding sequences and many SVs are heterozygous, suggesting that SVs might impact gene and allele-specific expression. Most SVs are uniquely present in only one clinical isolate, indicating that SVs represent a significant source of intraspecies genetic variation. We identify multiple, distinct SVs at the centromeres of Chromosome 4 and Chromosome 5, including inversions and transposon polymorphisms. These two chromosomes are often aneuploid in drug-resistant clinical isolates and can form isochromosome structures with breakpoints near the centromere. Further screening of 100 clinical isolates confirms the widespread presence of centromeric SVs in C. albicans, often appearing in a heterozygous state, indicating that SVs are contributing to centromere evolution in C. albicans Together, these findings highlight that SVs and TEs are common across diverse clinical isolates of C. albicans and that the centromeres of this organism are important sites of genome rearrangement.
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Affiliation(s)
- Ursula Oggenfuss
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Robert T Todd
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota 55455, USA
- Department of Biology, Bard College, Annandale-on-Hudson, New York 12504, USA
| | - Natthapon Soisangwan
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Bailey Kemp
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Alison Guyer
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Annette Beach
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Anna Selmecki
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota 55455, USA;
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Fagundes WC, Huang YS, Häußler S, Langner T. From Lesions to Lessons: Two Decades of Filamentous Plant Pathogen Genomics. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2025; 38:187-205. [PMID: 39813026 DOI: 10.1094/mpmi-09-24-0115-fi] [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: 01/16/2025]
Abstract
Many filamentous microorganisms, such as fungi and oomycetes, have evolved the ability to colonize plants and cause devastating crop diseases. Coevolutionary conflicts with their hosts have shaped the genomes of these plant pathogens. Over the past 20 years, genomics and genomics-enabled technologies have revealed remarkable diversity in genome size, architecture, and gene regulatory mechanisms. Technical and conceptual advances continue to provide novel insights into evolutionary dynamics, diversification of distinct genomic compartments, and facilitated molecular disease diagnostics. In this review, we discuss how genomics has advanced our understanding of genome organization and plant-pathogen coevolution and provide a perspective on future developments in the field. [Formula: see text] Copyright © 2025 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
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Affiliation(s)
| | - Yu-Seng Huang
- Max-Planck-Institute for Biology, 72076 Tübingen, Germany
| | - Sophia Häußler
- Max-Planck-Institute for Biology, 72076 Tübingen, Germany
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Jay A, Jordan DF, Gerstein A, Landry CR. The role of gene copy number variation in antimicrobial resistance in human fungal pathogens. NPJ ANTIMICROBIALS AND RESISTANCE 2025; 3:1. [PMID: 39781035 PMCID: PMC11703754 DOI: 10.1038/s44259-024-00072-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2024] [Accepted: 12/05/2024] [Indexed: 01/11/2025]
Abstract
Faced with the burden of increasing resistance to antifungals in many fungal pathogens and the constant emergence of new drug-resistant strains, it is essential to assess the importance of various resistance mechanisms. Fungi have relatively plastic genomes and can tolerate genomic copy number variation (CNV) caused by aneuploidy and gene amplification or deletion. In many cases, these genomic changes lead to adaptation to stressful conditions, including those caused by antifungal drugs. Here, we specifically examine the contribution of CNVs to antifungal resistance. We undertook a thorough literature search, collecting reports of antifungal resistance caused by a CNV, and classifying the examples of CNV-conferred resistance into four main mechanisms. We find that in human fungal pathogens, there is little evidence that gene copy number plays a major role in the emergence of antifungal resistance compared to other types of mutations. We discuss why we might be underestimating their importance and new approaches being used to study them.
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Affiliation(s)
- Adarsh Jay
- Département de Biochimie, de Microbiologie et de Bio-informatique, Faculté des Sciences et de Génie, Université Laval, Québec City, G1V 0A6 Canada
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec City, G1V 0A6 Canada
- PROTEO, Le regroupement québécois de recherche sur la fonction, l’ingénierie et les applications des protéines, Université Laval, Québec City, G1V 0A6 Canada
- Centre de Recherche sur les Données Massives, Université Laval, Québec City, G1V 0A6 Canada
| | - David F. Jordan
- Département de Biochimie, de Microbiologie et de Bio-informatique, Faculté des Sciences et de Génie, Université Laval, Québec City, G1V 0A6 Canada
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec City, G1V 0A6 Canada
- PROTEO, Le regroupement québécois de recherche sur la fonction, l’ingénierie et les applications des protéines, Université Laval, Québec City, G1V 0A6 Canada
- Centre de Recherche sur les Données Massives, Université Laval, Québec City, G1V 0A6 Canada
| | - Aleeza Gerstein
- Department of Microbiology, The University of Manitoba, Winnipeg, R3T 2N2 Canada
- Department of Statistics, The University of Manitoba, Winnipeg, R3T 2N2 Canada
| | - Christian R. Landry
- Département de Biochimie, de Microbiologie et de Bio-informatique, Faculté des Sciences et de Génie, Université Laval, Québec City, G1V 0A6 Canada
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec City, G1V 0A6 Canada
- PROTEO, Le regroupement québécois de recherche sur la fonction, l’ingénierie et les applications des protéines, Université Laval, Québec City, G1V 0A6 Canada
- Centre de Recherche sur les Données Massives, Université Laval, Québec City, G1V 0A6 Canada
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Jones DAB, Rybak K, Hossain M, Bertazzoni S, Williams A, Tan KC, Phan HTT, Hane JK. Repeat-induced point mutations driving Parastagonospora nodorum genomic diversity are balanced by selection against non-synonymous mutations. Commun Biol 2024; 7:1614. [PMID: 39627497 PMCID: PMC11615325 DOI: 10.1038/s42003-024-07327-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Accepted: 11/27/2024] [Indexed: 12/06/2024] Open
Abstract
Parastagonospora nodorum is necrotrophic fungal pathogen of wheat with significant genomic resources. Population-level pangenome data for 173 isolates, of which 156 were from Western Australia (WA) and 17 were international, were examined for overall genomic diversity and effector gene content. A heterothallic core population occurred across all regions of WA, with asexually-reproducing clonal clusters in dryer northern regions. High potential for SNP diversity in the form of repeat-induced point mutation (RIP)-like transitions, was observed across the genome, suggesting widespread 'RIP-leakage' from transposon-rich repetitive sequences into non-repetitive regions. The strong potential for RIP-like mutations was balanced by negative selection against non-synonymous SNPs, that was observed within protein-coding regions. Protein isoform profiles of known effector loci (SnToxA, SnTox1, SnTox3, SnTox267, and SnTox5) indicated low-levels of non-synonymous and high-levels of silent RIP-like mutations. Effector predictions identified 186 candidate secreted predicted effector proteins (CSEPs), 69 of which had functional annotations and included confirmed effectors. Pangenome-based effector isoform profiles across WA were distinct from global isolates and were conserved relative to population structure, and may enable new approaches for monitoring crop disease pathotypes.
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Affiliation(s)
- Darcy A B Jones
- Centre for Crop & Disease Management, School of Molecular & Life Sciences, Curtin University, Perth, WA, Australia
| | - Kasia Rybak
- Centre for Crop & Disease Management, School of Molecular & Life Sciences, Curtin University, Perth, WA, Australia
| | - Mohitul Hossain
- Centre for Crop & Disease Management, School of Molecular & Life Sciences, Curtin University, Perth, WA, Australia
| | - Stefania Bertazzoni
- Centre for Crop & Disease Management, School of Molecular & Life Sciences, Curtin University, Perth, WA, Australia
| | - Angela Williams
- Centre for Crop & Disease Management, School of Molecular & Life Sciences, Curtin University, Perth, WA, Australia
| | - Kar-Chun Tan
- Centre for Crop & Disease Management, School of Molecular & Life Sciences, Curtin University, Perth, WA, Australia
| | - Huyen T T Phan
- Centre for Crop & Disease Management, School of Molecular & Life Sciences, Curtin University, Perth, WA, Australia
| | - James K Hane
- Centre for Crop & Disease Management, School of Molecular & Life Sciences, Curtin University, Perth, WA, Australia.
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Gyawali N, Hao Y, Lin G, Huang J, Bika R, Daza L, Zheng H, Cruppe G, Caragea D, Cook D, Valent B, Liu S. Using recurrent neural networks to detect supernumerary chromosomes in fungal strains causing blast diseases. NAR Genom Bioinform 2024; 6:lqae108. [PMID: 39165675 PMCID: PMC11333962 DOI: 10.1093/nargab/lqae108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 06/27/2024] [Accepted: 08/06/2024] [Indexed: 08/22/2024] Open
Abstract
The genomes of the fungus Magnaporthe oryzae that causes blast diseases on diverse grass species, including major crops, have indispensable core-chromosomes and may contain supernumerary chromosomes, also known as mini-chromosomes. These mini-chromosomes are speculated to provide effector gene mobility, and may transfer between strains. To understand the biology of mini-chromosomes, it is valuable to be able to detect whether a M. oryzae strain possesses a mini-chromosome. Here, we applied recurrent neural network models for classifying DNA sequences as arising from core- or mini-chromosomes. The models were trained with sequences from available core- and mini-chromosome assemblies, and then used to predict the presence of mini-chromosomes in a global collection of M. oryzae isolates using short-read DNA sequences. The model predicted that mini-chromosomes were prevalent in M. oryzae isolates. Interestingly, at least one mini-chromosome was present in all recent wheat isolates, but no mini-chromosomes were found in early isolates collected before 1991, indicating a preferential selection for strains carrying mini-chromosomes in recent years. The model was also used to identify assembled contigs derived from mini-chromosomes. In summary, our study has developed a reliable method for categorizing DNA sequences and showcases an application of recurrent neural networks in predictive genomics.
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Affiliation(s)
- Nikesh Gyawali
- Department of Computer Science, Kansas State University, Manhattan, KS 66506, USA
| | - Yangfan Hao
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
| | - Guifang Lin
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
| | - Jun Huang
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
| | - Ravi Bika
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
| | - Lidia Calderon Daza
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
| | - Huakun Zheng
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
| | - Giovana Cruppe
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
| | - Doina Caragea
- Department of Computer Science, Kansas State University, Manhattan, KS 66506, USA
| | - David Cook
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
| | - Barbara Valent
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
| | - Sanzhen Liu
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
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Lapalu N, Simon A, Lu A, Plaumann PL, Amselem J, Pigné S, Auger A, Koch C, Dallery JF, O'Connell RJ. Complete genome of the Medicago anthracnose fungus, Colletotrichum destructivum, reveals a mini-chromosome-like region within a core chromosome. Microb Genom 2024; 10:001283. [PMID: 39166978 PMCID: PMC11338638 DOI: 10.1099/mgen.0.001283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 07/22/2024] [Indexed: 08/23/2024] Open
Abstract
Colletotrichum destructivum (Cd) is a phytopathogenic fungus causing significant economic losses on forage legume crops (Medicago and Trifolium species) worldwide. To gain insights into the genetic basis of fungal virulence and host specificity, we sequenced the genome of an isolate from Medicago sativa using long-read (PacBio) technology. The resulting genome assembly has a total length of 51.7 Mb and comprises ten core chromosomes and two accessory chromosomes, all of which were sequenced from telomere to telomere. A total of 15, 631 gene models were predicted, including genes encoding potentially pathogenicity-related proteins such as candidate-secreted effectors (484), secondary metabolism key enzymes (110) and carbohydrate-active enzymes (619). Synteny analysis revealed extensive structural rearrangements in the genome of Cd relative to the closely related Brassicaceae pathogen, Colletotrichum higginsianum. In addition, a 1.2 Mb species-specific region was detected within the largest core chromosome of Cd that has all the characteristics of fungal accessory chromosomes (transposon-rich, gene-poor, distinct codon usage), providing evidence for exchange between these two genomic compartments. This region was also unique in having undergone extensive intra-chromosomal segmental duplications. Our findings provide insights into the evolution of accessory regions and possible mechanisms for generating genetic diversity in this asexual fungal pathogen.
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Affiliation(s)
- Nicolas Lapalu
- Université Paris-Saclay, INRAE, UR BIOGER, 91120 Palaiseau, France
| | - Adeline Simon
- Université Paris-Saclay, INRAE, UR BIOGER, 91120 Palaiseau, France
| | - Antoine Lu
- Université Paris-Saclay, INRAE, UR BIOGER, 91120 Palaiseau, France
| | - Peter-Louis Plaumann
- Division of Biochemistry, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Joëlle Amselem
- Université Paris-Saclay, INRAE, URGI, 78000 Versailles, France
| | - Sandrine Pigné
- Université Paris-Saclay, INRAE, UR BIOGER, 91120 Palaiseau, France
| | - Annie Auger
- Université Paris-Saclay, INRAE, UR BIOGER, 91120 Palaiseau, France
| | - Christian Koch
- Division of Biochemistry, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
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Tralamazza SM, Gluck-Thaler E, Feurtey A, Croll D. Copy number variation introduced by a massive mobile element facilitates global thermal adaptation in a fungal wheat pathogen. Nat Commun 2024; 15:5728. [PMID: 38977688 PMCID: PMC11231334 DOI: 10.1038/s41467-024-49913-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 06/25/2024] [Indexed: 07/10/2024] Open
Abstract
Copy number variation (CNV) can drive rapid evolution in changing environments. In microbial pathogens, such adaptation is a key factor underpinning epidemics and colonization of new niches. However, the genomic determinants of such adaptation remain poorly understood. Here, we systematically investigate CNVs in a large genome sequencing dataset spanning a worldwide collection of 1104 genomes from the major wheat pathogen Zymoseptoria tritici. We found overall strong purifying selection acting on most CNVs. Genomic defense mechanisms likely accelerated gene loss over episodes of continental colonization. Local adaptation along climatic gradients was likely facilitated by CNVs affecting secondary metabolite production and gene loss in general. One of the strongest loci for climatic adaptation is a highly conserved gene of the NAD-dependent Sirtuin family. The Sirtuin CNV locus localizes to an ~68-kb Starship mobile element unique to the species carrying genes highly expressed during plant infection. The element has likely lost the ability to transpose, demonstrating how the ongoing domestication of cargo-carrying selfish elements can contribute to selectable variation within populations. Our work highlights how standing variation in gene copy numbers at the global scale can be a major factor driving climatic and metabolic adaptation in microbial species.
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Affiliation(s)
- Sabina Moser Tralamazza
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, CH-2000, Neuchâtel, Switzerland
| | - Emile Gluck-Thaler
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, CH-2000, Neuchâtel, Switzerland
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, USA
| | - Alice Feurtey
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, CH-2000, Neuchâtel, Switzerland
- Plant Pathology, D-USYS, ETH Zurich, CH-8092, Zurich, Switzerland
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, CH-2000, Neuchâtel, Switzerland.
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Cissé OH, Ma L, Kovacs JA. Retracing the evolution of Pneumocystis species, with a focus on the human pathogen Pneumocystis jirovecii. Microbiol Mol Biol Rev 2024; 88:e0020222. [PMID: 38587383 PMCID: PMC11332345 DOI: 10.1128/mmbr.00202-22] [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: 04/09/2024] Open
Abstract
SUMMARYEvery human being is presumed to be infected by the fungus Pneumocystis jirovecii at least once in his or her lifetime. This fungus belongs to a large group of species that appear to exclusively infect mammals, with P. jirovecii being the only one known to cause disease in humans. The mystery of P. jirovecii origin and speciation is just beginning to unravel. Here, we provide a review of the major steps of P. jirovecii evolution. The Pneumocystis genus likely originated from soil or plant-associated organisms during the period of Cretaceous ~165 million years ago and successfully shifted to mammals. The transition coincided with a substantial loss of genes, many of which are related to the synthesis of nutrients that can be scavenged from hosts or cell wall components that could be targeted by the mammalian immune system. Following the transition, the Pneumocystis genus cospeciated with mammals. Each species specialized at infecting its own host. Host specialization is presumably built at least partially upon surface glycoproteins, whose protogene was acquired prior to the genus formation. P. jirovecii appeared at ~65 million years ago, overlapping with the emergence of the first primates. P. jirovecii and its sister species P. macacae, which infects macaques nowadays, may have had overlapping host ranges in the distant past. Clues from molecular clocks suggest that P. jirovecii did not cospeciate with humans. Molecular evidence suggests that Pneumocystis speciation involved chromosomal rearrangements and the mounting of genetic barriers that inhibit gene flow among species.
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Affiliation(s)
- Ousmane H. Cissé
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Liang Ma
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Joseph A. Kovacs
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
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10
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van Westerhoven AC, Aguilera-Galvez C, Nakasato-Tagami G, Shi-Kunne X, Martinez de la Parte E, Chavarro-Carrero E, Meijer HJG, Feurtey A, Maryani N, Ordóñez N, Schneiders H, Nijbroek K, Wittenberg AHJ, Hofstede R, García-Bastidas F, Sørensen A, Swennen R, Drenth A, Stukenbrock EH, Kema GHJ, Seidl MF. Segmental duplications drive the evolution of accessory regions in a major crop pathogen. THE NEW PHYTOLOGIST 2024; 242:610-625. [PMID: 38402521 DOI: 10.1111/nph.19604] [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: 08/05/2023] [Accepted: 02/01/2024] [Indexed: 02/26/2024]
Abstract
Many pathogens evolved compartmentalized genomes with conserved core and variable accessory regions (ARs) that carry effector genes mediating virulence. The fungal plant pathogen Fusarium oxysporum has such ARs, often spanning entire chromosomes. The presence of specific ARs influences the host range, and horizontal transfer of ARs can modify the pathogenicity of the receiving strain. However, how these ARs evolve in strains that infect the same host remains largely unknown. We defined the pan-genome of 69 diverse F. oxysporum strains that cause Fusarium wilt of banana, a significant constraint to global banana production, and analyzed the diversity and evolution of the ARs. Accessory regions in F. oxysporum strains infecting the same banana cultivar are highly diverse, and we could not identify any shared genomic regions and in planta-induced effectors. We demonstrate that segmental duplications drive the evolution of ARs. Furthermore, we show that recent segmental duplications specifically in accessory chromosomes cause the expansion of ARs in F. oxysporum. Taken together, we conclude that extensive recent duplications drive the evolution of ARs in F. oxysporum, which contribute to the evolution of virulence.
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Affiliation(s)
- Anouk C van Westerhoven
- Laboratory of Phytopathology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands
- Department of Biology, Theoretical Biology & Bioinformatics, Utrecht University, Padualaan 8, 3584 CH, Utrecht, the Netherlands
| | - Carolina Aguilera-Galvez
- Laboratory of Phytopathology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands
| | - Giuliana Nakasato-Tagami
- Laboratory of Phytopathology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands
| | - Xiaoqian Shi-Kunne
- Laboratory of Phytopathology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands
| | - Einar Martinez de la Parte
- Laboratory of Phytopathology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands
| | - Edgar Chavarro-Carrero
- Laboratory of Phytopathology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands
| | - Harold J G Meijer
- Laboratory of Phytopathology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands
- Department Biointeractions and Plant Health, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands
| | - Alice Feurtey
- Christian-Albrechts University of Kiel, Christian-Albrechts-Platz 4, 24118, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, August-Thienemann-Straße 2, 24306, Plön, Germany
- Plant Pathology, Eidgenössische Technische Hochschule Zürich, Rämistrasse 101, 8092, Zürich, Switzerland
| | - Nani Maryani
- Biology Education, Universitas Sultan Ageng Tirtayasa, Jalan Raya Palka No.Km 3, 42163, Banten, Indonesia
| | - Nadia Ordóñez
- Laboratory of Phytopathology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands
| | - Harrie Schneiders
- KeyGene, Agro Business Park 90, 6708 PW, Wageningen, the Netherlands
| | - Koen Nijbroek
- KeyGene, Agro Business Park 90, 6708 PW, Wageningen, the Netherlands
| | | | - Rene Hofstede
- KeyGene, Agro Business Park 90, 6708 PW, Wageningen, the Netherlands
| | | | - Anker Sørensen
- KeyGene, Agro Business Park 90, 6708 PW, Wageningen, the Netherlands
| | - Ronny Swennen
- Division of Crop Biotechnics, Laboratory of Tropical Crop Improvement, Catholic University of Leuven, Oude Markt 13, 3000, Leuven, Belgium
- International Institute of Tropical Agriculture, Plot 15 Naguru E Rd, Kampala, PO Box 7878, Uganda
| | - Andre Drenth
- The University of Queensland, St Lucia, 4072, Brisbane, Queensland, Australia
| | - Eva H Stukenbrock
- Christian-Albrechts University of Kiel, Christian-Albrechts-Platz 4, 24118, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, August-Thienemann-Straße 2, 24306, Plön, Germany
| | - Gert H J Kema
- Laboratory of Phytopathology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands
| | - Michael F Seidl
- Department of Biology, Theoretical Biology & Bioinformatics, Utrecht University, Padualaan 8, 3584 CH, Utrecht, the Netherlands
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11
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Habig M, Grasse AV, Müller J, Stukenbrock EH, Leitner H, Cremer S. Frequent horizontal chromosome transfer between asexual fungal insect pathogens. Proc Natl Acad Sci U S A 2024; 121:e2316284121. [PMID: 38442176 PMCID: PMC10945790 DOI: 10.1073/pnas.2316284121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 01/24/2024] [Indexed: 03/07/2024] Open
Abstract
Entire chromosomes are typically only transmitted vertically from one generation to the next. The horizontal transfer of such chromosomes has long been considered improbable, yet gained recent support in several pathogenic fungi where it may affect the fitness or host specificity. To date, it is unknown how these transfers occur, how common they are, and whether they can occur between different species. In this study, we show multiple independent instances of horizontal transfers of the same accessory chromosome between two distinct strains of the asexual entomopathogenic fungus Metarhizium robertsii during experimental co-infection of its insect host, the Argentine ant. Notably, only the one chromosome-but no other-was transferred from the donor to the recipient strain. The recipient strain, now harboring the accessory chromosome, exhibited a competitive advantage under certain host conditions. By phylogenetic analysis, we further demonstrate that the same accessory chromosome was horizontally transferred in a natural environment between M. robertsii and another congeneric insect pathogen, Metarhizium guizhouense. Hence, horizontal chromosome transfer is not limited to the observed frequent events within species during experimental infections but also occurs naturally across species. The accessory chromosome that was transferred contains genes that may be involved in its preferential horizontal transfer or support its establishment. These genes encode putative histones and histone-modifying enzymes, as well as putative virulence factors. Our study reveals that both intra- and interspecies horizontal transfer of entire chromosomes is more frequent than previously assumed, likely representing a not uncommon mechanism for gene exchange.
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Affiliation(s)
- Michael Habig
- Environmental Genomics, Christian-Albrechts University of Kiel, Kiel24118, Germany
- Max Planck Institute for Evolutionary Biology, Plön24306, Germany
| | - Anna V. Grasse
- Institute of Science and Technology Austria (ISTA), Klosterneuburg3400, Austria
| | - Judith Müller
- Environmental Genomics, Christian-Albrechts University of Kiel, Kiel24118, Germany
- Max Planck Institute for Evolutionary Biology, Plön24306, Germany
| | - Eva H. Stukenbrock
- Environmental Genomics, Christian-Albrechts University of Kiel, Kiel24118, Germany
- Max Planck Institute for Evolutionary Biology, Plön24306, Germany
| | - Hanna Leitner
- Institute of Science and Technology Austria (ISTA), Klosterneuburg3400, Austria
| | - Sylvia Cremer
- Institute of Science and Technology Austria (ISTA), Klosterneuburg3400, Austria
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12
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Liu S, Lin G, Ramachandran SR, Daza LC, Cruppe G, Tembo B, Singh PK, Cook D, Pedley KF, Valent B. Rapid mini-chromosome divergence among fungal isolates causing wheat blast outbreaks in Bangladesh and Zambia. THE NEW PHYTOLOGIST 2024; 241:1266-1276. [PMID: 37984076 DOI: 10.1111/nph.19402] [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: 10/20/2023] [Accepted: 10/27/2023] [Indexed: 11/22/2023]
Abstract
The fungal pathogen, Magnaporthe oryzae Triticum pathotype, causing wheat blast disease was first identified in South America and recently spread across continents to South Asia and Africa. Here, we studied the genetic relationship among isolates found on the three continents. Magnaporthe oryzae strains closely related to a South American field isolate B71 were found to have caused the wheat blast outbreaks in South Asia and Africa. Genomic variation among isolates from the three continents was examined using an improved B71 reference genome and whole-genome sequences. We found strong evidence to support that the outbreaks in Bangladesh and Zambia were caused by the introductions of genetically separated isolates, although they were all close to B71 and, therefore, collectively referred to as the B71 branch. In addition, B71 branch strains carried at least one supernumerary mini-chromosome. Genome assembly of a Zambian strain revealed that its mini-chromosome was similar to the B71 mini-chromosome but with a high level of structural variation. Our findings show that while core genomes of the multiple introductions are highly similar, the mini-chromosomes have undergone marked diversification. The maintenance of the mini-chromosome and rapid genomic changes suggest the mini-chromosomes may serve important virulence or niche adaptation roles under diverse environmental conditions.
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Affiliation(s)
- Sanzhen Liu
- Department of Plant Pathology, Kansas State University, Manhattan, KS, 66506-5502, USA
| | - Guifang Lin
- Department of Plant Pathology, Kansas State University, Manhattan, KS, 66506-5502, USA
| | - Sowmya R Ramachandran
- United States Department of Agriculture-Agricultural Research Service (USDA-ARS), Foreign Disease-Weed Science Research Unit, Ft. Detrick, MD, 21702-9253, USA
| | - Lidia Calderon Daza
- Department of Plant Pathology, Kansas State University, Manhattan, KS, 66506-5502, USA
| | - Giovana Cruppe
- Department of Plant Pathology, Kansas State University, Manhattan, KS, 66506-5502, USA
| | - Batiseba Tembo
- Zambia Agricultural Research Institute, Mt. Makulu Central Research Station, Lusaka, 10101, Zambia
| | - Pawan Kumar Singh
- International Maize and Wheat Improvement Center (CIMMYT), Texcoco, 56237, Mexico
| | - David Cook
- Department of Plant Pathology, Kansas State University, Manhattan, KS, 66506-5502, USA
| | - Kerry F Pedley
- United States Department of Agriculture-Agricultural Research Service (USDA-ARS), Foreign Disease-Weed Science Research Unit, Ft. Detrick, MD, 21702-9253, USA
| | - Barbara Valent
- Department of Plant Pathology, Kansas State University, Manhattan, KS, 66506-5502, USA
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13
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Kamble A, Michavila S, Gimenez-Ibanez S, Redkar A. Shared infection strategy of a fungal pathogen across diverse lineages of land plants, the Fusarium example. CURRENT OPINION IN PLANT BIOLOGY 2024; 77:102498. [PMID: 38142620 DOI: 10.1016/j.pbi.2023.102498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 11/30/2023] [Accepted: 11/30/2023] [Indexed: 12/26/2023]
Abstract
Plants engage with a wide variety of microorganisms either in parasitic or mutualistic relationships, which have helped them to adapt to terrestrial ecosystems. Microbial interactions have driven plant evolution and led to the emergence of complex interaction outcomes via suppression of host defenses by evolving pathogens. The evolution of plant-microbe interactions is shaped by conserved host and pathogen gene modules and fast-paced lineage-specific adaptability which determines the interaction outcome. Recent findings from different microbes ranging from bacteria, oomycetes, and fungi suggest recurrent concepts in establishing interactions with evolutionarily distant plant hosts, but also clade-specific adaptation that ultimately contributes to pathogenicity. Here, we revisit some of the latest features that illustrate shared colonization strategies of the fungal pathogen Fusarium oxysporum on distant plant lineages and lineage-specific adaptability of mini-chromosomal units encoding effectors, for shaping host-specific pathogenicity in angiosperms.
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Affiliation(s)
- Avinash Kamble
- Department of Botany, Savitribai Phule Pune University, Ganeshkhind, Pune, 411007, India
| | - Santiago Michavila
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología CSIC, Campus Universidad Autonoma, Madrid, 28049, Spain
| | - Selena Gimenez-Ibanez
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología CSIC, Campus Universidad Autonoma, Madrid, 28049, Spain
| | - Amey Redkar
- National Centre for Biological Sciences, Tata Institute of Fundamental Research (NCBS-TIFR), GKVK Campus, Bellary Road, Bengaluru, 560065, India.
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14
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Zaccaron AZ, Stergiopoulos I. Analysis of five near-complete genome assemblies of the tomato pathogen Cladosporium fulvum uncovers additional accessory chromosomes and structural variations induced by transposable elements effecting the loss of avirulence genes. BMC Biol 2024; 22:25. [PMID: 38281938 PMCID: PMC10823647 DOI: 10.1186/s12915-024-01818-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 01/04/2024] [Indexed: 01/30/2024] Open
Abstract
BACKGROUND Fungal plant pathogens have dynamic genomes that allow them to rapidly adapt to adverse conditions and overcome host resistance. One way by which this dynamic genome plasticity is expressed is through effector gene loss, which enables plant pathogens to overcome recognition by cognate resistance genes in the host. However, the exact nature of these loses remains elusive in many fungi. This includes the tomato pathogen Cladosporium fulvum, which is the first fungal plant pathogen from which avirulence (Avr) genes were ever cloned and in which loss of Avr genes is often reported as a means of overcoming recognition by cognate tomato Cf resistance genes. A recent near-complete reference genome assembly of C. fulvum isolate Race 5 revealed a compartmentalized genome architecture and the presence of an accessory chromosome, thereby creating a basis for studying genome plasticity in fungal plant pathogens and its impact on avirulence genes. RESULTS Here, we obtained near-complete genome assemblies of four additional C. fulvum isolates. The genome assemblies had similar sizes (66.96 to 67.78 Mb), number of predicted genes (14,895 to 14,981), and estimated completeness (98.8 to 98.9%). Comparative analysis that included the genome of isolate Race 5 revealed high levels of synteny and colinearity, which extended to the density and distribution of repetitive elements and of repeat-induced point (RIP) mutations across homologous chromosomes. Nonetheless, structural variations, likely mediated by transposable elements and effecting the deletion of the avirulence genes Avr4E, Avr5, and Avr9, were also identified. The isolates further shared a core set of 13 chromosomes, but two accessory chromosomes were identified as well. Accessory chromosomes were significantly smaller in size, and one carried pseudogenized copies of two effector genes. Whole-genome alignments further revealed genomic islands of near-zero nucleotide diversity interspersed with islands of high nucleotide diversity that co-localized with repeat-rich regions. These regions were likely generated by RIP, which generally asymmetrically affected the genome of C. fulvum. CONCLUSIONS Our results reveal new evolutionary aspects of the C. fulvum genome and provide new insights on the importance of genomic structural variations in overcoming host resistance in fungal plant pathogens.
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Affiliation(s)
- Alex Z Zaccaron
- Department of Plant Pathology, University of California Davis, Davis, CA, 95616-8751, USA
| | - Ioannis Stergiopoulos
- Department of Plant Pathology, University of California Davis, Davis, CA, 95616-8751, USA.
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15
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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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16
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Bernasconi A, Lorrain C, Flury P, Alassimone J, McDonald BA, Sánchez-Vallet A. Virulent strains of Zymoseptoria tritici suppress the host immune response and facilitate the success of avirulent strains in mixed infections. PLoS Pathog 2023; 19:e1011767. [PMID: 37972205 PMCID: PMC10721197 DOI: 10.1371/journal.ppat.1011767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 12/14/2023] [Accepted: 10/19/2023] [Indexed: 11/19/2023] Open
Abstract
Plants interact with a plethora of pathogenic microorganisms in nature. Pathogen-plant interaction experiments focus mainly on single-strain infections, typically ignoring the complexity of multi-strain infections even though mixed infections are common and critical for the infection outcome. The wheat pathogen Zymoseptoria tritici forms highly diverse fungal populations in which several pathogen strains often colonize the same leaf. Despite the importance of mixed infections, the mechanisms governing interactions between a mixture of pathogen strains within a plant host remain largely unexplored. Here we demonstrate that avirulent pathogen strains benefit from being in mixed infections with virulent strains. We show that virulent strains suppress the wheat immune response, allowing avirulent strains to colonize the apoplast and to reproduce. Our experiments indicate that virulent strains in mixed infections can suppress the plant immune system, probably facilitating the persistence of avirulent pathogen strains in fields planted with resistant host plants.
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Affiliation(s)
- Alessio Bernasconi
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Cécile Lorrain
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Priska Flury
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Julien Alassimone
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Bruce A. McDonald
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Andrea Sánchez-Vallet
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
- Centro de Biotecnología y Genómica de Plantas (CBGP/Universidad Politécnica de Madrid-Instituto Nacional de Investigación Agraria y Alimentaria/Centro Superior de Investigaciones Científicas (INIA/CSIC), Campus de Montegancedo, Pozuelo de Alarcón (Madrid) Spain
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17
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Sugihara Y, Abe Y, Takagi H, Abe A, Shimizu M, Ito K, Kanzaki E, Oikawa K, Kourelis J, Langner T, Win J, Białas A, Lüdke D, Contreras MP, Chuma I, Saitoh H, Kobayashi M, Zheng S, Tosa Y, Banfield MJ, Kamoun S, Terauchi R, Fujisaki K. Disentangling the complex gene interaction networks between rice and the blast fungus identifies a new pathogen effector. PLoS Biol 2023; 21:e3001945. [PMID: 36656825 PMCID: PMC9851567 DOI: 10.1371/journal.pbio.3001945] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 12/05/2022] [Indexed: 01/20/2023] Open
Abstract
Studies focused solely on single organisms can fail to identify the networks underlying host-pathogen gene-for-gene interactions. Here, we integrate genetic analyses of rice (Oryza sativa, host) and rice blast fungus (Magnaporthe oryzae, pathogen) and uncover a new pathogen recognition specificity of the rice nucleotide-binding domain and leucine-rich repeat protein (NLR) immune receptor Pik, which mediates resistance to M. oryzae expressing the avirulence effector gene AVR-Pik. Rice Piks-1, encoded by an allele of Pik-1, recognizes a previously unidentified effector encoded by the M. oryzae avirulence gene AVR-Mgk1, which is found on a mini-chromosome. AVR-Mgk1 has no sequence similarity to known AVR-Pik effectors and is prone to deletion from the mini-chromosome mediated by repeated Inago2 retrotransposon sequences. AVR-Mgk1 is detected by Piks-1 and by other Pik-1 alleles known to recognize AVR-Pik effectors; recognition is mediated by AVR-Mgk1 binding to the integrated heavy metal-associated (HMA) domain of Piks-1 and other Pik-1 alleles. Our findings highlight how complex gene-for-gene interaction networks can be disentangled by applying forward genetics approaches simultaneously to the host and pathogen. We demonstrate dynamic coevolution between an NLR integrated domain and multiple families of effector proteins.
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Affiliation(s)
- Yu Sugihara
- Iwate Biotechnology Research Center, Kitakami, Iwate, Japan
- Crop Evolution Laboratory, Kyoto University, Mozume, Muko, Kyoto, Japan
- The Sainsbury Laboratory, University of East Anglia, Norwich, United Kingdom
| | - Yoshiko Abe
- Iwate Biotechnology Research Center, Kitakami, Iwate, Japan
| | - Hiroki Takagi
- Iwate Biotechnology Research Center, Kitakami, Iwate, Japan
| | - Akira Abe
- Iwate Biotechnology Research Center, Kitakami, Iwate, Japan
| | - Motoki Shimizu
- Iwate Biotechnology Research Center, Kitakami, Iwate, Japan
| | - Kazue Ito
- Iwate Biotechnology Research Center, Kitakami, Iwate, Japan
| | - Eiko Kanzaki
- Iwate Biotechnology Research Center, Kitakami, Iwate, Japan
| | - Kaori Oikawa
- Iwate Biotechnology Research Center, Kitakami, Iwate, Japan
| | - Jiorgos Kourelis
- The Sainsbury Laboratory, University of East Anglia, Norwich, United Kingdom
| | - Thorsten Langner
- The Sainsbury Laboratory, University of East Anglia, Norwich, United Kingdom
| | - Joe Win
- The Sainsbury Laboratory, University of East Anglia, Norwich, United Kingdom
| | - Aleksandra Białas
- The Sainsbury Laboratory, University of East Anglia, Norwich, United Kingdom
| | - Daniel Lüdke
- The Sainsbury Laboratory, University of East Anglia, Norwich, United Kingdom
| | | | - Izumi Chuma
- Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Japan
| | | | | | - Shuan Zheng
- Iwate Biotechnology Research Center, Kitakami, Iwate, Japan
- Crop Evolution Laboratory, Kyoto University, Mozume, Muko, Kyoto, Japan
| | - Yukio Tosa
- Graduate School of Agricultural Science, Kobe University, Kobe, Japan
| | - Mark J. Banfield
- Department of Biochemistry and Metabolism, John Innes Centre, Norwich Research Park, Norwich, United Kingdom
| | - Sophien Kamoun
- The Sainsbury Laboratory, University of East Anglia, Norwich, United Kingdom
| | - Ryohei Terauchi
- Iwate Biotechnology Research Center, Kitakami, Iwate, Japan
- Crop Evolution Laboratory, Kyoto University, Mozume, Muko, Kyoto, Japan
| | - Koki Fujisaki
- Iwate Biotechnology Research Center, Kitakami, Iwate, Japan
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18
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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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19
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Bergin SA, Zhao F, Ryan AP, Müller CA, Nieduszynski CA, Zhai B, Rolling T, Hohl TM, Morio F, Scully J, Wolfe KH, Butler G. Systematic Analysis of Copy Number Variations in the Pathogenic Yeast Candida parapsilosis Identifies a Gene Amplification in RTA3 That is Associated with Drug Resistance. mBio 2022; 13:e0177722. [PMID: 36121151 PMCID: PMC9600344 DOI: 10.1128/mbio.01777-22] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 08/31/2022] [Indexed: 01/12/2023] Open
Abstract
We analyzed the genomes of 170 C. parapsilosis isolates and identified multiple copy number variations (CNVs). We identified two genes, RTA3 (CPAR2_104610) and ARR3 (CPAR2_601050), each of which was the target of multiple independent amplification events. Phylogenetic analysis shows that most of these amplifications originated only once. For ARR3, which encodes a putative arsenate transporter, 8 distinct CNVs were identified, ranging in size from 2.3 kb to 10.5 kb with 3 to 23 copies. For RTA3, 16 distinct CNVs were identified, ranging in size from 0.3 kb to 4.5 kb with 2 to ~50 copies. One unusual amplification resulted in a DUP-TRP/INV-DUP structure similar to some human CNVs. RTA3 encodes a putative phosphatidylcholine (PC) floppase which is known to regulate the inward translocation of PC in Candida albicans. We found that an increased copy number of RTA3 correlated with resistance to miltefosine, an alkylphosphocholine drug that affects PC metabolism. Additionally, we conducted an adaptive laboratory evolution experiment in which two C. parapsilosis isolates were cultured in increasing concentrations of miltefosine. Two genes, CPAR2_303950 and CPAR2_102700, coding for putative PC flippases homologous to S. cerevisiae DNF1 gained homozygous protein-disrupting mutations in the evolved strains. Overall, our results show that C. parapsilosis can gain resistance to miltefosine, a drug that has recently been granted orphan drug designation approval by the United States Food and Drug Administration for the treatment of invasive candidiasis, through both CNVs or loss-of-function alleles in one of the flippase genes. IMPORTANCE Copy number variations (CNVs) are an important source of genomic diversity that have been associated with drug resistance. We identify two unusual CNVs in the human fungal pathogen Candida parapsilosis. Both target a single gene (RTA3 or ARR3), and they have occurred multiple times in multiple isolates. The copy number of RTA3, a putative floppase that controls the inward translocation of lipids in the cell membrane, correlates with resistance to miltefosine, a derivative of phosphatidylcholine (PC) that was originally developed as an anticancer drug. In 2021, miltefosine was designated an orphan drug by the United States Food and Drug Administration for the treatment of invasive candidiasis. Importantly, we find that resistance to miltefosine is also caused by mutations in flippases, which control the outward movement of lipids, and that many C. parapsilosis isolates are prone to easily acquiring an increased resistance to miltefosine.
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Affiliation(s)
- Sean A. Bergin
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin, Ireland
| | - Fang Zhao
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin, Ireland
| | - Adam P. Ryan
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin, Ireland
| | - Carolin A. Müller
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Conrad A. Nieduszynski
- Earlham Institute, Norwich, United Kingdom
- School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
| | - Bing Zhai
- Infectious Disease Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York, USA
- Immunology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, New York, USA
- Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Thierry Rolling
- Infectious Disease Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York, USA
- Immunology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Tobias M. Hohl
- Infectious Disease Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York, USA
- Immunology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, New York, USA
- Department of Medicine, Weill Cornell Medical College, New York, New York, USA
| | - Florent Morio
- Nantes Université, CHU de Nantes, Cibles et Médicaments des Infections et de l'Immunité, IICiMed, Nantes, France
| | - Jillian Scully
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin, Ireland
| | - Kenneth H. Wolfe
- School of Medicine, Conway Institute, University College Dublin, Belfield, Dublin, Ireland
| | - Geraldine Butler
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin, Ireland
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20
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Kilaru S, Fantozzi E, Cannon S, Schuster M, Chaloner TM, Guiu-Aragones C, Gurr SJ, Steinberg G. Zymoseptoria tritici white-collar complex integrates light, temperature and plant cues to initiate dimorphism and pathogenesis. Nat Commun 2022; 13:5625. [PMID: 36163135 PMCID: PMC9512790 DOI: 10.1038/s41467-022-33183-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 09/07/2022] [Indexed: 11/08/2022] Open
Abstract
Transitioning from spores to hyphae is pivotal to host invasion by the plant pathogenic fungus Zymoseptoria tritici. This dimorphic switch can be initiated by high temperature in vitro (~27 °C); however, such a condition may induce cellular heat stress, questioning its relevance to field infections. Here, we study the regulation of the dimorphic switch by temperature and other factors. Climate data from wheat-growing areas indicate that the pathogen sporadically experiences high temperatures such as 27 °C during summer months. However, using a fluorescent dimorphic switch reporter (FDR1) in four wild-type strains, we show that dimorphic switching already initiates at 15-18 °C, and is enhanced by wheat leaf surface compounds. Transcriptomics reveals 1261 genes that are up- or down-regulated in hyphae of all strains. These pan-strain core dimorphism genes (PCDGs) encode known effectors, dimorphism and transcription factors, and light-responsive proteins (velvet factors, opsins, putative blue light receptors). An FDR1-based genetic screen reveals a crucial role for the white-collar complex (WCC) in dimorphism and virulence, mediated by control of PCDG expression. Thus, WCC integrates light with biotic and abiotic cues to orchestrate Z. tritici infection.
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Affiliation(s)
- Sreedhar Kilaru
- Biosciences, University of Exeter, Stocker Road, EX4 4QD, Exeter, UK
| | - Elena Fantozzi
- Biosciences, University of Exeter, Stocker Road, EX4 4QD, Exeter, UK
| | - Stuart Cannon
- Biosciences, University of Exeter, Stocker Road, EX4 4QD, Exeter, UK
| | - Martin Schuster
- Biosciences, University of Exeter, Stocker Road, EX4 4QD, Exeter, UK
| | - Thomas M Chaloner
- Biosciences, University of Exeter, Stocker Road, EX4 4QD, Exeter, UK
| | | | - Sarah J Gurr
- Biosciences, University of Exeter, Stocker Road, EX4 4QD, Exeter, UK
- University of Utrecht, Padualaan 8, Utrecht, 3584 CH, The Netherlands
| | - Gero Steinberg
- Biosciences, University of Exeter, Stocker Road, EX4 4QD, Exeter, UK.
- University of Utrecht, Padualaan 8, Utrecht, 3584 CH, The Netherlands.
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21
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Bernasconi A, Alassimone J, McDonald BA, Sánchez‐Vallet A. Asexual reproductive potential trumps virulence as a predictor of competitive ability in mixed infections. Environ Microbiol 2022; 24:4369-4381. [PMID: 35437879 PMCID: PMC9790533 DOI: 10.1111/1462-2920.16018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 04/13/2022] [Indexed: 12/30/2022]
Abstract
Natural infections frequently involve several co-infecting pathogen strains. These mixed infections can affect the extent of the infection, the transmission success of the pathogen and the eventual epidemic outcome. To date, few studies have investigated how mixed infections affect transmission between hosts. Zymoseptoria tritici is a highly diverse wheat pathogen in which multiple strains often coexist in the same lesion. Here we demonstrate that the most competitive strains often exclude their competitors during serial passages of mixed infections. The outcome of the competition depended on both the host genotype and the genotypes of the competing pathogen strains. Differences in virulence among the strains were not associated with competitive advantages during transmission, while differences in reproductive potential had a strong effect on strain competitive ability. Overall, our findings suggest that host specialization is determined mainly by the ability to successfully transmit offspring to new hosts during mixed infections.
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Affiliation(s)
- Alessio Bernasconi
- Plant Pathology, Institute of Integrative Biology, ETH ZürichZürichCH‐8092Switzerland
| | - Julien Alassimone
- Plant Pathology, Institute of Integrative Biology, ETH ZürichZürichCH‐8092Switzerland
| | - Bruce A. McDonald
- Plant Pathology, Institute of Integrative Biology, ETH ZürichZürichCH‐8092Switzerland
| | - Andrea Sánchez‐Vallet
- Plant Pathology, Institute of Integrative Biology, ETH ZürichZürichCH‐8092Switzerland
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22
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McDonald BA, Suffert F, Bernasconi A, Mikaberidze A. How large and diverse are field populations of fungal plant pathogens? The case of Zymoseptoria tritici. Evol Appl 2022; 15:1360-1373. [PMID: 36187182 PMCID: PMC9488677 DOI: 10.1111/eva.13434] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 05/28/2022] [Accepted: 06/06/2022] [Indexed: 12/02/2022] Open
Abstract
Pathogen populations differ in the amount of genetic diversity they contain. Populations carrying higher genetic diversity are thought to have a greater evolutionary potential than populations carrying less diversity. We used published studies to estimate the range of values associated with two critical components of genetic diversity, the number of unique pathogen genotypes and the number of spores produced during an epidemic, for the septoria tritici blotch pathogen Zymoseptoria tritici. We found that wheat fields experiencing typical levels of infection are likely to carry between 3.1 and 14.0 million pathogen genotypes per hectare and produce at least 2.1-9.9 trillion pycnidiospores per hectare. Given the experimentally derived mutation rate of 3 × 10-10 substitutions per site per cell division, we estimate that between 27 and 126 million pathogen spores carrying adaptive mutations to counteract fungicides and resistant cultivars will be produced per hectare during a growing season. This suggests that most of the adaptive mutations that have been observed in Z. tritici populations can emerge through local selection from standing genetic variation that already exists within each field. The consequences of these findings for disease management strategies are discussed.
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Affiliation(s)
- Bruce A. McDonald
- Plant Pathology GroupInstitute of Integrative Biology, ETH ZurichZurichSwitzerland
| | | | - Alessio Bernasconi
- Plant Pathology GroupInstitute of Integrative Biology, ETH ZurichZurichSwitzerland
| | - Alexey Mikaberidze
- School of Agriculture, Policy and DevelopmentUniversity of ReadingReadingUK
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23
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Xia C, Qiu A, Wang M, Liu T, Chen W, Chen X. Current Status and Future Perspectives of Genomics Research in the Rust Fungi. Int J Mol Sci 2022; 23:9629. [PMID: 36077025 PMCID: PMC9456177 DOI: 10.3390/ijms23179629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 08/22/2022] [Accepted: 08/22/2022] [Indexed: 11/16/2022] Open
Abstract
Rust fungi in Pucciniales have caused destructive plant epidemics, have become more aggressive with new virulence, rapidly adapt to new environments, and continually threaten global agriculture. With the rapid advancement of genome sequencing technologies and data analysis tools, genomics research on many of the devastating rust fungi has generated unprecedented insights into various aspects of rust biology. In this review, we first present a summary of the main findings in the genomics of rust fungi related to variations in genome size and gene composition between and within species. Then we show how the genomics of rust fungi has promoted our understanding of the pathogen virulence and population dynamics. Even with great progress, many questions still need to be answered. Therefore, we introduce important perspectives with emphasis on the genome evolution and host adaptation of rust fungi. We believe that the comparative genomics and population genomics of rust fungi will provide a further understanding of the rapid evolution of virulence and will contribute to monitoring the population dynamics for disease management.
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Affiliation(s)
- Chongjing Xia
- Wheat Research Institute, School of Life Sciences and Engineering, Southwest University of Science and Technology, Mianyang 621010, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Age Qiu
- Wheat Research Institute, School of Life Sciences and Engineering, Southwest University of Science and Technology, Mianyang 621010, China
| | - Meinan Wang
- Department of Plant Pathology, Washington State University, Pullman, WA 99164-6430, USA
| | - Taiguo Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Wanquan Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Xianming Chen
- Department of Plant Pathology, Washington State University, Pullman, WA 99164-6430, USA
- Wheat Health, Genetics, and Quality Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Pullman, WA 99164-6430, USA
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24
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Montezano Fernandes F, Vieira de Queiroz M, Lopes da Silva L, Maria Queiroz Azevedo D, Luis Badel J, Couto Alfenas A. Chromosomal polymorphism of the Ceratocystis fimbriata species complex in Brazil. Fungal Genet Biol 2022; 162:103728. [PMID: 35932991 DOI: 10.1016/j.fgb.2022.103728] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 07/15/2022] [Accepted: 07/23/2022] [Indexed: 11/04/2022]
Abstract
Ceratocystis fimbriata is an important pathogen that causes wilt in several plant species. Despite the importance of this pathogen, knowledge about its karyotypic polymorphism and genomic architecture is limited. The main objective of this study was to investigate the karyotype of isolates of the C. fimbriata species complex from different host plants and geographical origins in Brazil. First, the identity of the isolates was confirmed conducting multilocus sequence analysis (MLSA) phylogeny using β-tubulin (TUBB), translation elongation factor 1α (TEF-1α) and mating-type (MAT1 and MAT2) gene sequences. To investigate the chromosomal polymorphism, two conditions of pulsed-field gel electrophoresis (PFGE) were used and the karyotypes of the isolates obtained. The retrotransposon-microsatellite amplified polymorphism (REMAP) molecular marker was utilized to assess the genetic variability among isolates. In the MLSA utilizing the concatenated gene sequences, Ceratocystis cacaofunesta and C. fimbriata formed separate clades, but considerable variation among C. fimbriata isolates was observed. Polymorphism in chromosome number and size was found, indicating the existence of genomic differences among isolates and occurrence of chromosomal rearrangements in the species complex. The number of chromosomes varied from seven to nine and the estimated minimum chromosome sizes were estimated to be between 2.7 to 6.0 Mbp. Small polymorphic chromosomes ranging from 1.2 to 1.8 Mbp were observed in all isolates, raising the hypothesis that they could be supernumerary chromosomes. REMAP analysis revealed a high genetic variability and that isolates from the same host tend to group together in a same cluster. Our results bring new insights into the chromosomal diversity and genome organization of the C. fimbriata complex.
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Affiliation(s)
- Fernando Montezano Fernandes
- Laboratory of Forest Pathology, Department of Plant Pathology, Universidade Federal de Viçosa, Minas Gerais State, 36570-900, Brazil
| | - Marisa Vieira de Queiroz
- Laboratory of Molecular Genetics of Microorganisms, Department of Microbiology, Universidade Federal de Viçosa, Minas Gerais State, 36570-900, Brazil
| | - Leandro Lopes da Silva
- Laboratory of Molecular Genetics of Microorganisms, Department of Microbiology, Universidade Federal de Viçosa, Minas Gerais State, 36570-900, Brazil
| | - Daiana Maria Queiroz Azevedo
- Laboratory of Forest Pathology, Department of Plant Pathology, Universidade Federal de Viçosa, Minas Gerais State, 36570-900, Brazil
| | - Jorge Luis Badel
- Laboratory of Molecular Phytobacteriology, Department of Plant Pathology, Universidade Federal de Viçosa, Minas Gerais State, 36570-900, Brazil
| | - Acelino Couto Alfenas
- Laboratory of Forest Pathology, Department of Plant Pathology, Universidade Federal de Viçosa, Minas Gerais State, 36570-900, Brazil.
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25
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Komluski J, Stukenbrock EH, Habig M. Non-Mendelian transmission of accessory chromosomes in fungi. Chromosome Res 2022; 30:241-253. [PMID: 35881207 PMCID: PMC9508043 DOI: 10.1007/s10577-022-09691-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 03/15/2022] [Accepted: 04/11/2022] [Indexed: 11/27/2022]
Abstract
Non-Mendelian transmission has been reported for various genetic elements, ranging from small transposons to entire chromosomes. One prime example of such a transmission pattern are B chromosomes in plants and animals. Accessory chromosomes in fungi are similar to B chromosomes in showing presence/absence polymorphism and being non-essential. How these chromosomes are transmitted during meiosis is however poorly understood—despite their often high impact on the fitness of the host. For several fungal organisms, a non-Mendelian transmission or a mechanistically unique meiotic drive of accessory chromosomes have been reported. In this review, we provide an overview of the possible mechanisms that can cause the non-Mendelian transmission or meiotic drives of fungal accessory chromosomes. We compare processes responsible for the non-Mendelian transmission of accessory chromosomes for different fungal eukaryotes and discuss the structural traits of fungal accessory chromosomes affecting their meiotic transmission. We conclude that research on fungal accessory chromosomes, due to their small size, ease of sequencing, and epigenetic profiling, can complement the study of B chromosomes in deciphering factors that influence and regulate the non-Mendelian transmission of entire chromosomes.
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Affiliation(s)
- Jovan Komluski
- Environmental Genomics, Christian-Albrechts University of Kiel, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Eva H Stukenbrock
- Environmental Genomics, Christian-Albrechts University of Kiel, Kiel, Germany.
- Max Planck Institute for Evolutionary Biology, Plön, Germany.
| | - Michael Habig
- Environmental Genomics, Christian-Albrechts University of Kiel, Kiel, Germany.
- Max Planck Institute for Evolutionary Biology, Plön, Germany.
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26
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Redkar A, Sabale M, Zuccaro A, Di Pietro A. Determinants of endophytic and pathogenic lifestyle in root colonizing fungi. CURRENT OPINION IN PLANT BIOLOGY 2022; 67:102226. [PMID: 35526366 DOI: 10.1016/j.pbi.2022.102226] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 03/28/2022] [Accepted: 03/30/2022] [Indexed: 06/14/2023]
Abstract
Plant-fungal interactions in the soil crucially impact crop productivity and can range from highly beneficial to detrimental. Accumulating evidence suggests that some root-colonizing fungi shift between endophytic and pathogenic behaviour depending on the host species and that combinations of effector proteins collectively shape the fungal lifestyle on a given plant. In this review we discuss recent advances in our understanding of how fungal infection strategies on roots can lead to contrasting outcomes for the host. We highlight functional similarities and differences in compatibility determinants that control the colonization of specific-cell layers within plant roots, ultimately shaping the continuum between endophytic and pathogenic lifestyle.
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Affiliation(s)
- Amey Redkar
- Departamento de Genética, Universidad de Córdoba, 14071 Córdoba, Spain; Department of Botany, Savitribai Phule Pune University, Ganeshkhind, Pune, 411007, India.
| | - Mugdha Sabale
- Departamento de Genética, Universidad de Córdoba, 14071 Córdoba, Spain
| | - Alga Zuccaro
- University of Cologne, Institute for Plant Sciences, D-50674, Cologne, Germany; Cluster of Excellence on Plant Sciences (CEPLAS), D-50674, Cologne, Germany
| | - Antonio Di Pietro
- Departamento de Genética, Universidad de Córdoba, 14071 Córdoba, Spain.
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27
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Shi G, Kariyawasam G, Liu S, Leng Y, Zhong S, Ali S, Moolhuijzen P, Moffat CS, Rasmussen JB, Friesen TL, Faris JD, Liu Z. A Conserved Hypothetical Gene Is Required but Not Sufficient for Ptr ToxC Production in Pyrenophora tritici-repentis. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2022; 35:336-348. [PMID: 35100008 DOI: 10.1094/mpmi-12-21-0299-r] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The fungus Pyrenophora tritici-repentis causes tan spot, an important foliar disease of wheat worldwide. The fungal pathogen produces three necrotrophic effectors, namely Ptr ToxA, Ptr ToxB, and Ptr ToxC to induce necrosis or chlorosis in wheat. Both Ptr ToxA and Ptr ToxB are proteins, and their encoding genes have been cloned. Ptr ToxC was characterized as a low-molecular weight molecule 20 years ago but the one or more genes controlling its production in P. tritici-repentis are unknown. Here, we report the genetic mapping, molecular cloning, and functional analysis of a fungal gene that is required for Ptr ToxC production. The genetic locus controlling the production of Ptr ToxC, termed ToxC, was mapped to a subtelomeric region using segregating biparental populations, genome sequencing, and association analysis. Additional marker analysis further delimited ToxC to a 173-kb region. The predicted genes in the region were examined for presence/absence polymorphism in different races and isolates leading to the identification of a single candidate gene. Functional validation showed that this gene was required but not sufficient for Ptr ToxC production, thus it is designated as ToxC1. ToxC1 encoded a conserved hypothetical protein likely located on the vacuole membrane. The gene was highly expressed during infection, and only one haplotype was identified among 120 isolates sequenced. Our work suggests that Ptr ToxC is not a protein and is likely produced through a cascade of biosynthetic pathway. The identification of ToxC1 is a major step toward revealing the Ptr ToxC biosynthetic pathway and studying its molecular interactions with host factors.[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)
- Gongjun Shi
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108, U.S.A
| | - Gayan Kariyawasam
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108, U.S.A
| | - Sanzhen Liu
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, U.S.A
| | - Yueqiang Leng
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108, U.S.A
| | - Shaobin Zhong
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108, U.S.A
| | - Shaukat Ali
- Department of Agronomy, Horticulture & Plant Science, South Dakota State University Brookings, SD 57006, U.S.A
| | - Paula Moolhuijzen
- Center for Crop Disease and Management, School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia, Australia
| | - Caroline S Moffat
- Center for Crop Disease and Management, School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia, Australia
| | - Jack B Rasmussen
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108, U.S.A
| | - Timothy L Friesen
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108, U.S.A
- USDA-ARS Cereal Crops Research Unit, Edward T. Schafer Agricultural Research Center, Fargo, ND 58102, U.S.A
| | - Justin D Faris
- USDA-ARS Cereal Crops Research Unit, Edward T. Schafer Agricultural Research Center, Fargo, ND 58102, U.S.A
| | - Zhaohui Liu
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108, U.S.A
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28
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Abstract
This chapter describes protocols for the development of consensus chemical phenotypes or "metabolomes" of fungal populations using ultra-high pressure liquid chromatography coupled to high resolution mass spectrometry (UPLC-HRMS). Isolates are cultured using multiple media conditions to elicit the expression of diverse secondary metabolite biosynthetic gene clusters. The mycelium and spent culture media are extracted using organic solvents and profiled by ultra-high pressure chromatography coupled with a high resolution Thermo Orbitrap XL mass spectrometer with the ability to trap and fragment ions to general MS2 spectra. MS data preprocessing is explained and illustrated using the freely available software MZMine 2. Through data processing, binary matrices of mass features can be generated and then combined into a consensus secondary metabolite phenotype of all isolates grown in all media conditions. The production of consensus chemical phenotypes is useful for screening large fungal populations (both inter and intra-species populations) for isolates potentially expressing novel secondary metabolites or analogs of known secondary metabolites.
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Affiliation(s)
- Thomas E Witte
- Agriculture and Agri-Food Canada, Ottawa Research and Development Centre, Ottawa, ON, Canada
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON, Canada
| | - David P Overy
- Agriculture and Agri-Food Canada, Ottawa Research and Development Centre, Ottawa, ON, Canada.
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29
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Epigenetic modifications affect the rate of spontaneous mutations in a pathogenic fungus. Nat Commun 2021; 12:5869. [PMID: 34620872 PMCID: PMC8497519 DOI: 10.1038/s41467-021-26108-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 09/17/2021] [Indexed: 12/17/2022] Open
Abstract
Mutations are the source of genetic variation and the substrate for evolution. Genome-wide mutation rates appear to be affected by selection and are probably adaptive. Mutation rates are also known to vary along genomes, possibly in response to epigenetic modifications, but causality is only assumed. In this study we determine the direct impact of epigenetic modifications and temperature stress on mitotic mutation rates in a fungal pathogen using a mutation accumulation approach. Deletion mutants lacking epigenetic modifications confirm that histone mark H3K27me3 increases whereas H3K9me3 decreases the mutation rate. Furthermore, cytosine methylation in transposable elements (TE) increases the mutation rate 15-fold resulting in significantly less TE mobilization. Also accessory chromosomes have significantly higher mutation rates. Finally, we find that temperature stress substantially elevates the mutation rate. Taken together, we find that epigenetic modifications and environmental conditions modify the rate and the location of spontaneous mutations in the genome and alter its evolutionary trajectory.
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30
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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: 40] [Impact Index Per Article: 10.0] [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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31
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Fan Y, Gale AN, Bailey A, Barnes K, Colotti K, Mass M, Morina LB, Robertson B, Schwab R, Tselepidakis N, Timp W. Genome and transcriptome of a pathogenic yeast, Candida nivariensis. G3 (BETHESDA, MD.) 2021; 11:jkab137. [PMID: 33890630 PMCID: PMC8496292 DOI: 10.1093/g3journal/jkab137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 04/11/2021] [Indexed: 11/14/2022]
Abstract
We present a highly contiguous genome and transcriptome of the pathogenic yeast, Candida nivariensis. We sequenced both the DNA and RNA of this species using both the Oxford Nanopore Technologies and Illumina platforms. We assembled the genome into an 11.8 Mb draft composed of 16 contigs with an N50 of 886 Kb, including a circular mitochondrial sequence of 28 Kb. Using direct RNA nanopore sequencing and Illumina cDNA sequencing, we constructed an annotation of our new assembly, supplemented by lifting over genes from Saccharomyces cerevisiae and Candida glabrata.
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Affiliation(s)
- Yunfan Fan
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Andrew N Gale
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Anna Bailey
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Kali Barnes
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Kiersten Colotti
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Michal Mass
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Luke B Morina
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Bailey Robertson
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Remy Schwab
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Niki Tselepidakis
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Winston Timp
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Division of Infectious Disease, Department of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
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Badet T, Fouché S, Hartmann FE, Zala M, Croll D. Machine-learning predicts genomic determinants of meiosis-driven structural variation in a eukaryotic pathogen. Nat Commun 2021; 12:3551. [PMID: 34112792 PMCID: PMC8192914 DOI: 10.1038/s41467-021-23862-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 05/11/2021] [Indexed: 02/05/2023] Open
Abstract
Species harbor extensive structural variation underpinning recent adaptive evolution. However, the causality between genomic features and the induction of new rearrangements is poorly established. Here, we analyze a global set of telomere-to-telomere genome assemblies of a fungal pathogen of wheat to establish a nucleotide-level map of structural variation. We show that the recent emergence of pesticide resistance has been disproportionally driven by rearrangements. We use machine learning to train a model on structural variation events based on 30 chromosomal sequence features. We show that base composition and gene density are the major determinants of structural variation. Retrotransposons explain most inversion, indel and duplication events. We apply our model to Arabidopsis thaliana and show that our approach extends to more complex genomes. Finally, we analyze complete genomes of haploid offspring in a four-generation pedigree. Meiotic crossover locations are enriched for new rearrangements consistent with crossovers being mutational hotspots. The model trained on species-wide structural variation accurately predicts the position of >74% of newly generated variants along the pedigree. The predictive power highlights causality between specific sequence features and the induction of chromosomal rearrangements. Our work demonstrates that training sequence-derived models can accurately identify regions of intrinsic DNA instability in eukaryotic genomes.
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Affiliation(s)
- Thomas Badet
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Simone Fouché
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
- Plant Pathology, Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
| | - Fanny E Hartmann
- Ecologie Systématique Evolution, Bâtiment 360, Univ. Paris-Sud, AgroParisTech, CNRS, Université Paris-Saclay, Orsay, France
| | - Marcello Zala
- Plant Pathology, Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland.
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Kariyawasam GK, Wyatt N, Shi G, Liu S, Yan C, Ma Y, Zhong S, Rasmussen JB, Moolhuijzen P, Moffat CS, Friesen TL, Liu Z. A genome-wide genetic linkage map and reference quality genome sequence for a new race in the wheat pathogen Pyrenophora tritici-repentis. Fungal Genet Biol 2021; 152:103571. [PMID: 34015431 DOI: 10.1016/j.fgb.2021.103571] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 02/23/2021] [Accepted: 03/01/2021] [Indexed: 10/21/2022]
Abstract
Pyrenophora tritici-repentis is an ascomycete fungus that causes tan spot of wheat. The disease has a worldwide distribution and can cause significant yield and quality losses in wheat production. The fungal pathogen is homothallic in nature, which means it can undergo sexual reproduction by selfing to produce pseudothecia on wheat stubble for seasonal survival. Since homothallism precludes the development of bi-parental fungal populations, no genetic linkage map has been developed for P. tritici-repentis for mapping and map-based cloning of fungal virulence genes. In this work, we created two heterothallic strains by deleting one of the mating type genes in each of two parental isolates 86-124 (race 2) and AR CrossB10 (a new race) and developed a bi-parental fungal population between them. The draft genome sequences of the two parental isolates were aligned to the Pt-1C-BFP reference sequence to mine single nucleotide polymorphisms (SNPs). A total of 225 SNP markers were developed for genotyping the entire population. Additionally, 75 simple sequence repeat, and two gene markers were also developed and used in the genotyping. The resulting linkage map consisted of 13 linkage groups spanning 5,075.83 cM in genetic distance. Because the parental isolate AR CrossB10 is a new race and produces Ptr ToxC, it was sequenced using long-read sequencing platforms and de novo assembled into contigs. The majority of the contigs were further anchored into chromosomes with the aid of the linkage maps. The whole genome comparison of AR CrossB10 to the reference genome of M4 revealed a few chromosomal rearrangements. The genetic linkage map and the new AR CrossB10 genome sequence are valuable tools for gene cloning in P. tritici-repentis.
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Affiliation(s)
- Gayan K Kariyawasam
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108, USA
| | - Nathan Wyatt
- USDA-ARS Cereal Crops Research Unit, Edward T. Schafer Agricultural Research Center, Fargo, ND 58102, USA
| | - Gongjun Shi
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108, USA
| | - Sanzhen Liu
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
| | - Changhui Yan
- Department of Computer Science, North Dakota State University, Fargo, ND 58108, USA
| | - Yongchao Ma
- Department of Computer Science, North Dakota State University, Fargo, ND 58108, USA
| | - Shaobin Zhong
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108, USA
| | - Jack B Rasmussen
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108, USA
| | - Paula Moolhuijzen
- Center for Crop Disease and Management, Department of Environment and Agriculture, Curtin University, Bentley, Western Australia, Australia
| | - Caroline S Moffat
- Center for Crop Disease and Management, Department of Environment and Agriculture, Curtin University, Bentley, Western Australia, Australia
| | - Timothy L Friesen
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108, USA; USDA-ARS Cereal Crops Research Unit, Edward T. Schafer Agricultural Research Center, Fargo, ND 58102, USA
| | - Zhaohui Liu
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108, USA.
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Witte TE, Villeneuve N, Boddy CN, Overy DP. Accessory Chromosome-Acquired Secondary Metabolism in Plant Pathogenic Fungi: The Evolution of Biotrophs Into Host-Specific Pathogens. Front Microbiol 2021; 12:664276. [PMID: 33968000 PMCID: PMC8102738 DOI: 10.3389/fmicb.2021.664276] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 03/09/2021] [Indexed: 11/25/2022] Open
Abstract
Accessory chromosomes are strain- or pathotype-specific chromosomes that exist in addition to the core chromosomes of a species and are generally not considered essential to the survival of the organism. Among pathogenic fungal species, accessory chromosomes harbor pathogenicity or virulence factor genes, several of which are known to encode for secondary metabolites that are involved in plant tissue invasion. Accessory chromosomes are of particular interest due to their capacity for horizontal transfer between strains and their dynamic "crosstalk" with core chromosomes. This review focuses exclusively on secondary metabolism (including mycotoxin biosynthesis) associated with accessory chromosomes in filamentous fungi and the role accessory chromosomes play in the evolution of secondary metabolite gene clusters. Untargeted metabolomics profiling in conjunction with genome sequencing provides an effective means of linking secondary metabolite products with their respective biosynthetic gene clusters that reside on accessory chromosomes. While the majority of literature describing accessory chromosome-associated toxin biosynthesis comes from studies of Alternaria pathotypes, the recent discovery of accessory chromosome-associated biosynthetic genes in Fusarium species offer fresh insights into the evolution of biosynthetic enzymes such as non-ribosomal peptide synthetases (NRPSs), polyketide synthases (PKSs) and regulatory mechanisms governing their expression.
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Affiliation(s)
- Thomas E. Witte
- Agriculture and Agri-Food Canada, Ottawa Research and Development Centre, Ottawa, ON, Canada
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Nicolas Villeneuve
- Agriculture and Agri-Food Canada, Ottawa Research and Development Centre, Ottawa, ON, Canada
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Christopher N. Boddy
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON, Canada
| | - David P. Overy
- Agriculture and Agri-Food Canada, Ottawa Research and Development Centre, Ottawa, ON, Canada
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Dutta A, Croll D, McDonald BA, Barrett LG. Maintenance of variation in virulence and reproduction in populations of an agricultural plant pathogen. Evol Appl 2021; 14:335-347. [PMID: 33664780 PMCID: PMC7896723 DOI: 10.1111/eva.13117] [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] [Received: 04/15/2020] [Revised: 07/04/2020] [Accepted: 08/13/2020] [Indexed: 11/27/2022] Open
Abstract
Genetic diversity within pathogen populations is critically important for predicting pathogen evolution, disease outcomes and prevalence. However, we lack a good understanding of the processes maintaining genetic variation and constraints on pathogen life-history evolution. Here, we analysed interactions between 12 wheat host genotypes and 145 strains of Zymoseptoria tritici from five global populations to investigate the evolution and maintenance of variation in pathogen virulence and reproduction. We found a strong positive correlation between virulence (amount of leaf necrosis) and reproduction (pycnidia density within lesions), with substantial variation in both traits maintained within populations. On average, highly virulent isolates exhibited higher reproduction, which might increase transmission potential in agricultural fields planted to homogeneous hosts at a high density. We further showed that pathogen strains with a narrow host range (i.e. specialists) for reproduction were on average less virulent, and those with a broader host range (i.e. generalists) were on average less fecund on a given specific host. These costs associated with adaptation to different host genotypes might constrain the emergence of generalists by disrupting the directional evolution of virulence and fecundity. We conclude that selection favouring pathogen strains that are virulent across diverse hosts, coupled with selection that maximizes fecundity on specific hosts, may explain the maintenance of these pathogenicity traits within and among populations.
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Affiliation(s)
- Anik Dutta
- Plant PathologyInstitute of Integrative BiologyETH ZurichZurichSwitzerland
| | - Daniel Croll
- Laboratory of Evolutionary GeneticsInstitute of BiologyUniversity of NeuchâtelNeuchâtelSwitzerland
| | - Bruce A. McDonald
- Plant PathologyInstitute of Integrative BiologyETH ZurichZurichSwitzerland
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Li J, Fokkens L, Conneely LJ, Rep M. Partial pathogenicity chromosomes in Fusarium oxysporum are sufficient to cause disease and can be horizontally transferred. Environ Microbiol 2020; 22:4985-5004. [PMID: 32452643 PMCID: PMC7818268 DOI: 10.1111/1462-2920.15095] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/13/2020] [Accepted: 05/21/2020] [Indexed: 01/05/2023]
Abstract
In Fusarium oxysporum f.sp. lycopersici, all effector genes reported so far - also called SIX genes - are located on a single accessory chromosome which is required for pathogenicity and can also be horizontally transferred to another strain. To narrow down the minimal region required for virulence, we selected partial pathogenicity chromosome deletion strains by fluorescence-assisted cell sorting of a strain in which the two arms of the pathogenicity chromosome were labelled with GFP and RFP respectively. By testing the virulence of these deletion mutants, we show that the complete long arm and part of the short arm of the pathogenicity chromosome are not required for virulence. In addition, we demonstrate that smaller versions of the pathogenicity chromosome can also be transferred to a non-pathogenic strain and they are sufficient to turn the non-pathogen into a pathogen. Surprisingly, originally non-pathogenic strains that had received a smaller version of the pathogenicity chromosome were much more aggressive than recipients with a complete pathogenicity chromosome. Whole genome sequencing analysis revealed that partial deletions of the pathogenicity chromosome occurred mainly close to repeats, and that spontaneous duplication of sequences in accessory regions is frequent both in chromosome deletion strains and in horizontal transfer strains.
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Affiliation(s)
- Jiming Li
- Molecular Plant PathologyUniversity of AmsterdamAmsterdam1098 XHThe Netherlands
| | - Like Fokkens
- Molecular Plant PathologyUniversity of AmsterdamAmsterdam1098 XHThe Netherlands
| | - Lee James Conneely
- Molecular Plant PathologyUniversity of AmsterdamAmsterdam1098 XHThe Netherlands
| | - Martijn Rep
- Molecular Plant PathologyUniversity of AmsterdamAmsterdam1098 XHThe Netherlands
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Abstract
Most genomes within the species complex of Fusarium oxysporum are organized into two compartments: the core chromosomes (CCs) and accessory chromosomes (ACs). As opposed to CCs, which are conserved and vertically transmitted to carry out essential housekeeping functions, lineage- or strain-specific ACs are believed to be initially horizontally acquired through unclear mechanisms. These two genomic compartments are different in terms of gene density, the distribution of transposable elements, and epigenetic markers. Although common in eukaryotes, the functional importance of ACs is uniquely emphasized among fungal species, specifically in relationship to fungal pathogenicity and their adaptation to diverse hosts. With a focus on the cross-kingdom fungal pathogen F. oxysporum, this review provides a summary of the differences between CCs and ACs based on current knowledge of gene functions, genome structures, and epigenetic signatures, and explores the transcriptional crosstalk between the core and accessory genomes.
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38
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Todd RT, Selmecki A. Expandable and reversible copy number amplification drives rapid adaptation to antifungal drugs. eLife 2020; 9:e58349. [PMID: 32687060 PMCID: PMC7371428 DOI: 10.7554/elife.58349] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 07/09/2020] [Indexed: 12/13/2022] Open
Abstract
Previously, we identified long repeat sequences that are frequently associated with genome rearrangements, including copy number variation (CNV), in many diverse isolates of the human fungal pathogen Candida albicans (Todd et al., 2019). Here, we describe the rapid acquisition of novel, high copy number CNVs during adaptation to azole antifungal drugs. Single-cell karyotype analysis indicates that these CNVs appear to arise via a dicentric chromosome intermediate and breakage-fusion-bridge cycles that are repaired using multiple distinct long inverted repeat sequences. Subsequent removal of the antifungal drug can lead to a dramatic loss of the CNV and reversion to the progenitor genotype and drug susceptibility phenotype. These findings support a novel mechanism for the rapid acquisition of antifungal drug resistance and provide genomic evidence for the heterogeneity frequently observed in clinical settings.
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Affiliation(s)
- Robert T Todd
- Department of Microbiology and Immunology, University of Minnesota Medical SchoolMinneapolis, MinnesotaUnited States
| | - Anna Selmecki
- Department of Microbiology and Immunology, University of Minnesota Medical SchoolMinneapolis, MinnesotaUnited States
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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: 227] [Impact Index Per Article: 45.4] [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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40
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Plaumann PL, Koch C. The Many Questions about Mini Chromosomes in Colletotrichum spp. PLANTS 2020; 9:plants9050641. [PMID: 32438596 PMCID: PMC7284448 DOI: 10.3390/plants9050641] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/08/2020] [Accepted: 05/14/2020] [Indexed: 11/16/2022]
Abstract
Many fungal pathogens carry accessory regions in their genome, which are not required for vegetative fitness. Often, although not always, these regions occur as relatively small chromosomes in different species. Such mini chromosomes appear to be a typical feature of many filamentous plant pathogens. Since these regions often carry genes coding for effectors or toxin-producing enzymes, they may be directly related to virulence of the respective pathogen. In this review, we outline the situation of small accessory chromosomes in the genus Colletotrichum, which accounts for ecologically important plant diseases. We summarize which species carry accessory chromosomes, their gene content, and chromosomal makeup. We discuss the large variation in size and number even between different isolates of the same species, their potential roles in host range, and possible mechanisms for intra- and interspecies exchange of these interesting genetic elements.
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41
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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: 3.2] [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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42
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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: 82] [Impact Index Per Article: 16.4] [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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43
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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: 0.2] [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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44
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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: 57] [Impact Index Per Article: 11.4] [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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45
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Wyatt NA, Richards JK, Brueggeman RS, Friesen TL. A Comparative Genomic Analysis of the Barley Pathogen Pyrenophora teres f. teres Identifies Subtelomeric Regions as Drivers of Virulence. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2020; 33:173-188. [PMID: 31502507 DOI: 10.1094/mpmi-05-19-0128-r] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Pyrenophora teres f. teres causes net form net blotch of barley and is an economically important pathogen throughout the world. However, P. teres f. teres is lacking in the genomic resources necessary to characterize the mechanisms of virulence. Recently a high-quality reference genome was generated for P. teres f. teres isolate 0-1. Here, we present the reference quality sequence and annotation of four new isolates and we use the five available P. teres f. teres genomes for an in-depth comparison, resulting in the generation of hypotheses pertaining to the potential mechanisms and evolution of virulence. Comparative analyses were performed between all five P. teres f. teres genomes, examining genomic organization, structural variations, and core and accessory genomic content, specifically focusing on the genomic characterization of known virulence loci and the localization of genes predicted to encode secreted and effector proteins. We showed that 14 of 15 currently published virulence quantitative trait loci (QTL) span accessory genomic regions, consistent with these accessory regions being important drivers of host adaptation. Additionally, these accessory genomic regions were frequently found in subtelomeric regions of chromosomes, with 10 of the 14 accessory region QTL localizing to subtelomeric regions. Comparative analysis of the subtelomeric regions of P. teres f. teres chromosomes revealed translocation events in which homology was detected between nonhomologous chromosomes at a significantly higher rate than the rest of the genome. These results indicate that the subtelomeric accessory genomic compartments not only harbor most of the known virulence loci but, also, that these regions have the capacity to rapidly evolve.
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Affiliation(s)
- Nathan A Wyatt
- Genomics and Bioinformatics Program, North Dakota State University, Fargo, ND, U.S.A
- Department of Plant Pathology, North Dakota State University
| | - Jonathan K Richards
- Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, LA, U.S.A
| | - Robert S Brueggeman
- Genomics and Bioinformatics Program, North Dakota State University, Fargo, ND, U.S.A
- Department of Plant Pathology, North Dakota State University
| | - Timothy L Friesen
- Genomics and Bioinformatics Program, North Dakota State University, Fargo, ND, U.S.A
- Department of Plant Pathology, North Dakota State University
- Cereal Crops Research Unit, Red River Valley Agricultural Research Center, USDA-ARS, Fargo, ND, U.S.A
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van Wyk S, Wingfield BD, De Vos L, van der Merwe NA, Santana QC, Steenkamp ET. Repeat-Induced Point Mutations Drive Divergence between Fusarium circinatum and Its Close Relatives. Pathogens 2019; 8:pathogens8040298. [PMID: 31847413 PMCID: PMC6963459 DOI: 10.3390/pathogens8040298] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 12/06/2019] [Accepted: 12/09/2019] [Indexed: 01/01/2023] Open
Abstract
The Repeat-Induced Point (RIP) mutation pathway is a fungal-specific genome defense mechanism that counteracts the deleterious effects of transposable elements. This pathway permanently mutates its target sequences by introducing cytosine to thymine transitions. We investigated the genome-wide occurrence of RIP in the pitch canker pathogen, Fusarium circinatum, and its close relatives in the Fusarium fujikuroi species complex (FFSC). Our results showed that the examined fungi all exhibited hallmarks of RIP, but that they differed in terms of the extent to which their genomes were affected by this pathway. RIP mutations constituted a large proportion of all the FFSC genomes, including both core and dispensable chromosomes, although the latter were generally more extensively affected by RIP. Large RIP-affected genomic regions were also much more gene sparse than the rest of the genome. Our data further showed that RIP-directed sequence diversification increased the variability between homologous regions of related species, and that RIP-affected regions can interfere with homologous recombination during meiosis, thereby contributing to post-mating segregation distortion. Taken together, these findings suggest that RIP can drive the independent divergence of chromosomes, alter chromosome architecture, and contribute to the divergence among F. circinatum and other members of this economically important group of fungi.
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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 2019; 11:3095-3105. [PMID: 31603209 PMCID: PMC6836716 DOI: 10.1093/gbe/evz224] [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: 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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Wang M, Fu H, Shen X, Ruan R, Rokas A, Li H. Genomic features and evolution of the conditionally dispensable chromosome in the tangerine pathotype of Alternaria alternata. MOLECULAR PLANT PATHOLOGY 2019; 20:1425-1438. [PMID: 31297970 PMCID: PMC6792136 DOI: 10.1111/mpp.12848] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The tangerine pathotype of the ascomycete fungus Alternaria alternata is the causal agent of citrus brown spot, which can result in significant losses of both yield and marketability for tangerines worldwide. A conditionally dispensable chromosome (CDC), which harbours the host-selective ACT toxin gene cluster, is required for tangerine pathogenicity of A. alternata. To understand the genetic makeup and evolution of the tangerine pathotype CDC, we isolated and sequenced the CDCs of the A. alternata Z7 strain and analysed the function and evolution of their genes. The A. alternata Z7 strain has two CDCs (~1.1 and ~0.8 Mb, respectively), and the longer Z7 CDC contains all but one contig of the shorter one. Z7 CDCs contain 254 predicted protein-coding genes, which are enriched in functional categories associated with 'metabolic process' (55 genes, P = 0.037). Relatively few of the CDC genes can be classified as carbohydrate-active enzymes (CAZymes) (4) and transporters (19) and none as kinases. Evolutionary analysis of the 254 CDC proteins showed that their evolutionary conservation tends to be restricted within the genus Alternaria and that the CDC genes evolve faster than genes in the essential chromosomes, likely due to fewer selective constraints. Interestingly, phylogenetic analysis suggested that four of the 25 genes responsible for the ACT toxin production were likely transferred from Colletotrichum (Sordariomycetes). Functional experiments showed that two of them are essential for the virulence of the tangerine pathotype of A. alternata. These results provide new insights into the function and evolution of CDC genes in Alternaria.
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Affiliation(s)
- Mingshuang Wang
- Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of BiotechnologyZhejiang UniversityHangzhou310058China
- Department of Biological SciencesVanderbilt UniversityNashvilleTN37235USA
- College of Life and Environmental SciencesHangzhou Normal UniversityHangzhou310036China
| | - Huilan Fu
- Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of BiotechnologyZhejiang UniversityHangzhou310058China
| | - Xing‐Xing Shen
- Department of Biological SciencesVanderbilt UniversityNashvilleTN37235USA
| | - Ruoxin Ruan
- Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of BiotechnologyZhejiang UniversityHangzhou310058China
- Hangzhou Academy of Agricultural SciencesHangzhou310024China
| | - Antonis Rokas
- Department of Biological SciencesVanderbilt UniversityNashvilleTN37235USA
| | - Hongye Li
- Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of BiotechnologyZhejiang UniversityHangzhou310058China
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Peng Z, Oliveira-Garcia E, Lin G, Hu Y, Dalby M, Migeon P, Tang H, Farman M, Cook D, White FF, Valent B, Liu S. Effector gene reshuffling involves dispensable mini-chromosomes in the wheat blast fungus. PLoS Genet 2019; 15:e1008272. [PMID: 31513573 PMCID: PMC6741851 DOI: 10.1371/journal.pgen.1008272] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 06/24/2019] [Indexed: 11/28/2022] Open
Abstract
Newly emerged wheat blast disease is a serious threat to global wheat production. Wheat blast is caused by a distinct, exceptionally diverse lineage of the fungus causing rice blast disease. Through sequencing a recent field isolate, we report a reference genome that includes seven core chromosomes and mini-chromosome sequences that harbor effector genes normally found on ends of core chromosomes in other strains. No mini-chromosomes were observed in an early field strain, and at least two from another isolate each contain different effector genes and core chromosome end sequences. The mini-chromosome is enriched in transposons occurring most frequently at core chromosome ends. Additionally, transposons in mini-chromosomes lack the characteristic signature for inactivation by repeat-induced point (RIP) mutation genome defenses. Our results, collectively, indicate that dispensable mini-chromosomes and core chromosomes undergo divergent evolutionary trajectories, and mini-chromosomes and core chromosome ends are coupled as a mobile, fast-evolving effector compartment in the wheat pathogen genome.
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Affiliation(s)
- Zhao Peng
- Department of Plant Pathology, Kansas State University, Manhattan, KS, United States of America
- Department of Plant Pathology, University of Florida, Gainesville, FL, United States of America
| | - Ely Oliveira-Garcia
- Department of Plant Pathology, Kansas State University, Manhattan, KS, United States of America
| | - Guifang Lin
- Department of Plant Pathology, Kansas State University, Manhattan, KS, United States of America
| | - Ying Hu
- Department of Plant Pathology, Kansas State University, Manhattan, KS, United States of America
| | - Melinda Dalby
- Department of Plant Pathology, Kansas State University, Manhattan, KS, United States of America
| | - Pierre Migeon
- Department of Plant Pathology, Kansas State University, Manhattan, KS, United States of America
| | - Haibao Tang
- Center for Genomics and Biotechnology and Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fujian, China
| | - Mark Farman
- Department of Plant Pathology, University of Kentucky, Lexington, KY, United States of America
| | - David Cook
- Department of Plant Pathology, Kansas State University, Manhattan, KS, United States of America
| | - Frank F. White
- Department of Plant Pathology, University of Florida, Gainesville, FL, United States of America
| | - Barbara Valent
- Department of Plant Pathology, Kansas State University, Manhattan, KS, United States of America
| | - Sanzhen Liu
- Department of Plant Pathology, Kansas State University, Manhattan, KS, United States of America
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50
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Peng Z, Oliveira-Garcia E, Lin G, Hu Y, Dalby M, Migeon P, Tang H, Farman M, Cook D, White FF, Valent B, Liu S. Effector gene reshuffling involves dispensable mini-chromosomes in the wheat blast fungus. PLoS Genet 2019; 15:e1008272. [PMID: 31513573 DOI: 10.1101/359455] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 06/24/2019] [Indexed: 05/26/2023] Open
Abstract
Newly emerged wheat blast disease is a serious threat to global wheat production. Wheat blast is caused by a distinct, exceptionally diverse lineage of the fungus causing rice blast disease. Through sequencing a recent field isolate, we report a reference genome that includes seven core chromosomes and mini-chromosome sequences that harbor effector genes normally found on ends of core chromosomes in other strains. No mini-chromosomes were observed in an early field strain, and at least two from another isolate each contain different effector genes and core chromosome end sequences. The mini-chromosome is enriched in transposons occurring most frequently at core chromosome ends. Additionally, transposons in mini-chromosomes lack the characteristic signature for inactivation by repeat-induced point (RIP) mutation genome defenses. Our results, collectively, indicate that dispensable mini-chromosomes and core chromosomes undergo divergent evolutionary trajectories, and mini-chromosomes and core chromosome ends are coupled as a mobile, fast-evolving effector compartment in the wheat pathogen genome.
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Affiliation(s)
- Zhao Peng
- Department of Plant Pathology, Kansas State University, Manhattan, KS, United States of America
- Department of Plant Pathology, University of Florida, Gainesville, FL, United States of America
| | - Ely Oliveira-Garcia
- Department of Plant Pathology, Kansas State University, Manhattan, KS, United States of America
| | - Guifang Lin
- Department of Plant Pathology, Kansas State University, Manhattan, KS, United States of America
| | - Ying Hu
- Department of Plant Pathology, Kansas State University, Manhattan, KS, United States of America
| | - Melinda Dalby
- Department of Plant Pathology, Kansas State University, Manhattan, KS, United States of America
| | - Pierre Migeon
- Department of Plant Pathology, Kansas State University, Manhattan, KS, United States of America
| | - Haibao Tang
- Center for Genomics and Biotechnology and Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fujian, China
| | - Mark Farman
- Department of Plant Pathology, University of Kentucky, Lexington, KY, United States of America
| | - David Cook
- Department of Plant Pathology, Kansas State University, Manhattan, KS, United States of America
| | - Frank F White
- Department of Plant Pathology, University of Florida, Gainesville, FL, United States of America
| | - Barbara Valent
- Department of Plant Pathology, Kansas State University, Manhattan, KS, United States of America
| | - Sanzhen Liu
- Department of Plant Pathology, Kansas State University, Manhattan, KS, United States of America
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