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Cohen AB, Cai G, Price DC, Molnar TJ, Zhang N, Hillman BI. The massive 340 megabase genome of Anisogramma anomala, a biotrophic ascomycete that causes eastern filbert blight of hazelnut. BMC Genomics 2024; 25:347. [PMID: 38580927 PMCID: PMC10998396 DOI: 10.1186/s12864-024-10198-1] [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: 05/12/2023] [Accepted: 03/07/2024] [Indexed: 04/07/2024] Open
Abstract
BACKGROUND The ascomycete fungus Anisogramma anomala causes Eastern Filbert Blight (EFB) on hazelnut (Corylus spp.) trees. It is a minor disease on its native host, the American hazelnut (C. americana), but is highly destructive on the commercially important European hazelnut (C. avellana). In North America, EFB has historically limited commercial production of hazelnut to west of the Rocky Mountains. A. anomala is an obligately biotrophic fungus that has not been grown in continuous culture, rendering its study challenging. There is a 15-month latency before symptoms appear on infected hazelnut trees, and only a sexual reproductive stage has been observed. Here we report the sequencing, annotation, and characterization of its genome. RESULTS The genome of A. anomala was assembled into 108 scaffolds totaling 342,498,352 nt with a GC content of 34.46%. Scaffold N50 was 33.3 Mb and L50 was 5. Nineteen scaffolds with lengths over 1 Mb constituted 99% of the assembly. Telomere sequences were identified on both ends of two scaffolds and on one end of another 10 scaffolds. Flow cytometry estimated the genome size of A. anomala at 370 Mb. The genome exhibits two-speed evolution, with 93% of the assembly as AT-rich regions (32.9% GC) and the other 7% as GC-rich (57.1% GC). The AT-rich regions consist predominantly of repeats with low gene content, while 90% of predicted protein coding genes were identified in GC-rich regions. Copia-like retrotransposons accounted for more than half of the genome. Evidence of repeat-induced point mutation (RIP) was identified throughout the AT-rich regions, and two copies of the rid gene and one of dim-2, the key genes in the RIP mutation pathway, were identified in the genome. Consistent with its homothallic sexual reproduction cycle, both MAT1-1 and MAT1-2 idiomorphs were found. We identified a large suite of genes likely involved in pathogenicity, including 614 carbohydrate active enzymes, 762 secreted proteins and 165 effectors. CONCLUSIONS This study reveals the genomic structure, composition, and putative gene function of the important pathogen A. anomala. It provides insight into the molecular basis of the pathogen's life cycle and a solid foundation for studying EFB.
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Affiliation(s)
- Alanna B Cohen
- Department of Plant Biology, Rutgers The State University of New Jersey, New Brunswick, NJ, 08901, USA
- Graduate Program in Microbial Biology, Rutgers The State University of New Jersey, New Brunswick, NJ, 08901, USA
| | - Guohong Cai
- Crop Production and Pest Control Research Unit, USDA-ARS, West Lafayette, IN, 47907, USA.
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA.
| | - Dana C Price
- Department of Entomology, Rutgers The State University of New Jersey, New Brunswick, NJ, 08901, USA
- Center for Vector Biology, Rutgers The State University of New Jersey, New Brunswick, NJ, 08901, USA
| | - Thomas J Molnar
- Department of Plant Biology, Rutgers The State University of New Jersey, New Brunswick, NJ, 08901, USA
| | - Ning Zhang
- Department of Plant Biology, Rutgers The State University of New Jersey, New Brunswick, NJ, 08901, USA
- Graduate Program in Microbial Biology, Rutgers The State University of New Jersey, New Brunswick, NJ, 08901, USA
- Department of Biochemistry and Microbiology, Rutgers The State University of New Jersey, New Brunswick, NJ, 08901, USA
| | - Bradley I Hillman
- Department of Plant Biology, Rutgers The State University of New Jersey, New Brunswick, NJ, 08901, USA.
- Graduate Program in Microbial Biology, Rutgers The State University of New Jersey, New Brunswick, NJ, 08901, USA.
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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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Hensen N, Bonometti L, Westerberg I, Brännström IO, Guillou S, Cros-Aarteil S, Calhoun S, Haridas S, Kuo A, Mondo S, Pangilinan J, Riley R, LaButti K, Andreopoulos B, Lipzen A, Chen C, Yan M, Daum C, Ng V, Clum A, Steindorff A, Ohm RA, Martin F, Silar P, Natvig DO, Lalanne C, Gautier V, Ament-Velásquez SL, Kruys Å, Hutchinson MI, Powell AJ, Barry K, Miller AN, Grigoriev IV, Debuchy R, Gladieux P, Hiltunen Thorén M, Johannesson H. Genome-scale phylogeny and comparative genomics of the fungal order Sordariales. Mol Phylogenet Evol 2023; 189:107938. [PMID: 37820761 DOI: 10.1016/j.ympev.2023.107938] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 09/28/2023] [Accepted: 10/04/2023] [Indexed: 10/13/2023]
Abstract
The order Sordariales is taxonomically diverse, and harbours many species with different lifestyles and large economic importance. Despite its importance, a robust genome-scale phylogeny, and associated comparative genomic analysis of the order is lacking. In this study, we examined whole-genome data from 99 Sordariales, including 52 newly sequenced genomes, and seven outgroup taxa. We inferred a comprehensive phylogeny that resolved several contentious relationships amongst families in the order, and cleared-up intrafamily relationships within the Podosporaceae. Extensive comparative genomics showed that genomes from the three largest families in the dataset (Chaetomiaceae, Podosporaceae and Sordariaceae) differ greatly in GC content, genome size, gene number, repeat percentage, evolutionary rate, and genome content affected by repeat-induced point mutations (RIP). All genomic traits showed phylogenetic signal, and ancestral state reconstruction revealed that the variation of the properties stems primarily from within-family evolution. Together, the results provide a thorough framework for understanding genome evolution in this important group of fungi.
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Affiliation(s)
- Noah Hensen
- Stockholm University, Department of Ecology, Environment and Plants Sciences, Stockholm, Sweden
| | - Lucas Bonometti
- University of Montpellier, PHIM Plant Health Institute, Montpellier, France
| | - Ivar Westerberg
- Stockholm University, Department of Ecology, Environment and Plants Sciences, Stockholm, Sweden
| | - Ioana Onut Brännström
- Oslo University, Natural History Museum, Oslo, Norway; Uppsala University, Department of Ecology and Genetics, Uppsala, Sweden
| | - Sonia Guillou
- University of Montpellier, PHIM Plant Health Institute, Montpellier, France
| | | | - Sara Calhoun
- Lawrence Berkeley National Laboratory, U.S. Department of Energy Joint Genome Institute, Berkeley, CA, USA
| | - Sajeet Haridas
- Lawrence Berkeley National Laboratory, U.S. Department of Energy Joint Genome Institute, Berkeley, CA, USA
| | - Alan Kuo
- Lawrence Berkeley National Laboratory, U.S. Department of Energy Joint Genome Institute, Berkeley, CA, USA
| | - Stephen Mondo
- Lawrence Berkeley National Laboratory, U.S. Department of Energy Joint Genome Institute, Berkeley, CA, USA
| | - Jasmyn Pangilinan
- Lawrence Berkeley National Laboratory, U.S. Department of Energy Joint Genome Institute, Berkeley, CA, USA
| | - Robert Riley
- Lawrence Berkeley National Laboratory, U.S. Department of Energy Joint Genome Institute, Berkeley, CA, USA
| | - Kurt LaButti
- Lawrence Berkeley National Laboratory, U.S. Department of Energy Joint Genome Institute, Berkeley, CA, USA
| | - Bill Andreopoulos
- Lawrence Berkeley National Laboratory, U.S. Department of Energy Joint Genome Institute, Berkeley, CA, USA
| | - Anna Lipzen
- Lawrence Berkeley National Laboratory, U.S. Department of Energy Joint Genome Institute, Berkeley, CA, USA
| | - Cindy Chen
- Lawrence Berkeley National Laboratory, U.S. Department of Energy Joint Genome Institute, Berkeley, CA, USA
| | - Mi Yan
- Lawrence Berkeley National Laboratory, U.S. Department of Energy Joint Genome Institute, Berkeley, CA, USA
| | - Chris Daum
- Lawrence Berkeley National Laboratory, U.S. Department of Energy Joint Genome Institute, Berkeley, CA, USA
| | - Vivian Ng
- Lawrence Berkeley National Laboratory, U.S. Department of Energy Joint Genome Institute, Berkeley, CA, USA
| | - Alicia Clum
- Lawrence Berkeley National Laboratory, U.S. Department of Energy Joint Genome Institute, Berkeley, CA, USA
| | - Andrei Steindorff
- Lawrence Berkeley National Laboratory, U.S. Department of Energy Joint Genome Institute, Berkeley, CA, USA
| | - Robin A Ohm
- Lawrence Berkeley National Laboratory, U.S. Department of Energy Joint Genome Institute, Berkeley, CA, USA
| | | | - Philippe Silar
- Université de Paris Cité, Laboratoire Interdisciplinaire des Energies de Demain, Paris, France
| | - Donald O Natvig
- University of New Mexico, Department of Biology, Albuquerque, USA
| | - Christophe Lalanne
- Université de Paris Cité, Laboratoire Interdisciplinaire des Energies de Demain, Paris, France
| | - Valérie Gautier
- Université de Paris Cité, Laboratoire Interdisciplinaire des Energies de Demain, Paris, France
| | | | - Åsa Kruys
- Uppsala University, Museum of Evolution, Uppsala, Sweden
| | | | - Amy Jo Powell
- Sandia National Laboratories, Dept. of Systems Design and Architecture, Albuquerque, USA
| | - Kerrie Barry
- Lawrence Berkeley National Laboratory, U.S. Department of Energy Joint Genome Institute, Berkeley, CA, USA
| | - Andrew N Miller
- University of Illinois Urbana-Champaign, Illinois Natural History Survey, USA
| | - Igor V Grigoriev
- Lawrence Berkeley National Laboratory, U.S. Department of Energy Joint Genome Institute, Berkeley, CA, USA; University of California Berkeley, Department of Plant and Microbial Biology, Berkeley, CA, USA
| | - Robert Debuchy
- Université Paris-Saclay, Institute for Integrative Biology of the Cell, Gif-sur-Yvette, France
| | - Pierre Gladieux
- University of Montpellier, PHIM Plant Health Institute, Montpellier, France
| | - Markus Hiltunen Thorén
- Stockholm University, Department of Ecology, Environment and Plants Sciences, Stockholm, Sweden; The Royal Swedish Academy of Sciences, Stockholm, Sweden
| | - Hanna Johannesson
- Stockholm University, Department of Ecology, Environment and Plants Sciences, Stockholm, Sweden; The Royal Swedish Academy of Sciences, Stockholm, Sweden.
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Rogério F, Baroncelli R, Cuevas-Fernández FB, Becerra S, Crouch J, Bettiol W, Azcárate-Peril MA, Malapi-Wight M, Ortega V, Betran J, Tenuta A, Dambolena JS, Esker PD, Revilla P, Jackson-Ziems TA, Hiltbrunner J, Munkvold G, Buhiniček I, Vicente-Villardón JL, Sukno SA, Thon MR. Population Genomics Provide Insights into the Global Genetic Structure of Colletotrichum graminicola, the Causal Agent of Maize Anthracnose. mBio 2023; 14:e0287822. [PMID: 36533926 PMCID: PMC9973043 DOI: 10.1128/mbio.02878-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 11/17/2022] [Indexed: 12/24/2022] Open
Abstract
Understanding the genetic diversity and mechanisms underlying genetic variation in pathogen populations is crucial to the development of effective control strategies. We investigated the genetic diversity and reproductive biology of Colletotrichum graminicola isolates which infect maize by sequencing the genomes of 108 isolates collected from 14 countries using restriction site-associated DNA sequencing (RAD-seq) and whole-genome sequencing (WGS). Clustering analyses based on single-nucleotide polymorphisms revealed three genetic groups delimited by continental origin, compatible with short-dispersal of the pathogen and geographic subdivision. Intra- and intercontinental migration was observed between Europe and South America, likely associated with the movement of contaminated germplasm. Low clonality, evidence of genetic recombination, and high phenotypic diversity were detected. We show evidence that, although it is rare (possibly due to losses of sexual reproduction- and meiosis-associated genes) C. graminicola can undergo sexual recombination. Our results support the hypotheses that intra- and intercontinental pathogen migration and genetic recombination have great impacts on the C. graminicola population structure. IMPORTANCE Plant pathogens cause significant reductions in yield and crop quality and cause enormous economic losses worldwide. Reducing these losses provides an obvious strategy to increase food production without further degrading natural ecosystems; however, this requires knowledge of the biology and evolution of the pathogens in agroecosystems. We employed a population genomics approach to investigate the genetic diversity and reproductive biology of the maize anthracnose pathogen (Colletotrichum graminicola) in 14 countries. We found that the populations are correlated with their geographical origin and that migration between countries is ongoing, possibly caused by the movement of infected plant material. This result has direct implications for disease management because migration can cause the movement of more virulent and/or fungicide-resistant genotypes. We conclude that genetic recombination is frequent (in contrast to the traditional view of C. graminicola being mainly asexual), which strongly impacts control measures and breeding programs aimed at controlling this disease.
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Affiliation(s)
- Flávia Rogério
- Instituto de Investigación en Agrobiotecnología (CIALE), Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain
| | - Riccardo Baroncelli
- Instituto de Investigación en Agrobiotecnología (CIALE), Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain
- Department of Agricultural and Food Sciences (DISTAL), University of Bologna, Bologna, Italy
| | - Francisco Borja Cuevas-Fernández
- Instituto de Investigación en Agrobiotecnología (CIALE), Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain
| | - Sioly Becerra
- Instituto de Investigación en Agrobiotecnología (CIALE), Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain
| | - JoAnne Crouch
- Foreign Disease and Weed Science Unit, United States Department of Agriculture, Fort Detrick, Maryland, USA
| | | | - M. Andrea Azcárate-Peril
- Center for Gastrointestinal Biology and Disease, Department of Medicine, School of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
- Division of Gastroenterology and Hepatology, Department of Medicine, School of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
- UNC Microbiome Core, Department of Medicine, School of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Martha Malapi-Wight
- USDA Animal and Plant Health Inspection Services, Biotechnology Regulatory Services, Riverdale, Maryland, USA
| | | | | | - Albert Tenuta
- Ontario Ministry of Agriculture, Food, and Rural Affairs, University of Guelph-Ridgetown, Ridgetown, Ontario, Canada
| | - José S. Dambolena
- Facultad de Ciencias Exactas Físicas y Naturales, Universidad Nacional de Córdoba, IMBIV-CONICET-ICTA, Córdoba, Argentina
| | - Paul D. Esker
- Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, State College, Pennsylvania, USA
| | - Pedro Revilla
- Misión Biológica de Galicia, Spanish National Research Council (CSIC), Pontevedra, Spain
| | | | | | - Gary Munkvold
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, Iowa, USA
| | - Ivica Buhiniček
- BC Institute for Breeding and Production of Field Crops, Dugo Selo, Croatia
| | | | - Serenella A. Sukno
- Instituto de Investigación en Agrobiotecnología (CIALE), Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain
| | - Michael R. Thon
- Instituto de Investigación en Agrobiotecnología (CIALE), Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain
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Nuclear Genome Sequence and Gene Expression of an Intracellular Fungal Endophyte Stimulating the Growth of Cranberry Plants. J Fungi (Basel) 2023; 9:jof9010126. [PMID: 36675947 PMCID: PMC9861600 DOI: 10.3390/jof9010126] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/04/2023] [Accepted: 01/11/2023] [Indexed: 01/18/2023] Open
Abstract
Ericaceae thrive in poor soil, which we postulate is facilitated by microbes living inside those plants. Here, we investigate the growth stimulation of the American cranberry (Vaccinium macrocarpon) by one of its fungal endosymbionts, EC4. We show that the symbiont resides inside the epidermal root cells of the host but extends into the rhizosphere via its hyphae. Morphological classification of this fungus is ambiguous, but phylogenetic inference based on 28S rRNA identifies EC4 as a Codinaeella species (Chaetosphaeriaceae, Sordariomycetes, Ascomycetes). We sequenced the genome and transcriptome of EC4, providing the first 'Omics' information of a Chaetosphaeriaceae fungus. The 55.3-Mbp nuclear genome contains 17,582 potential protein-coding genes, of which nearly 500 have the capacity to promote plant growth. For comparing gene sets involved in biofertilization, we annotated the published genome assembly of the plant-growth-promoting Trichoderma hamatum. The number of proteins involved in phosphate transport and solubilization is similar in the two fungi. In contrast, EC4 has ~50% more genes associated with ammonium, nitrate/nitrite transport, and phytohormone synthesis. The expression of 36 presumed plant-growth-promoting EC4 genes is stimulated when the fungus is in contact with the plant. Thus, Omics and in-plantae tests make EC4 a promising candidate for cranberry biofertilization on nutrient-poor soils.
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Zaccaron AZ, Chen LH, Samaras A, Stergiopoulos I. A chromosome-scale genome assembly of the tomato pathogen Cladosporium fulvum reveals a compartmentalized genome architecture and the presence of a dispensable chromosome. Microb Genom 2022; 8:000819. [PMID: 35471194 PMCID: PMC9453070 DOI: 10.1099/mgen.0.000819] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Accepted: 03/29/2022] [Indexed: 01/25/2023] Open
Abstract
Cladosporium fulvum is a fungal pathogen that causes leaf mould of tomato. The reference genome of this pathogen was released in 2012 but its high repetitive DNA content prevented a contiguous assembly and further prohibited the analysis of its genome architecture. In this study, we combined third generation sequencing technology with the Hi-C chromatin conformation capture technique, to produce a high-quality and near complete genome assembly and gene annotation of a Race 5 isolate of C. fulvum. The resulting genome assembly contained 67.17 Mb organized into 14 chromosomes (Chr1-to-Chr14), all of which were assembled telomere-to-telomere. The smallest of the chromosomes, Chr14, is only 460 kb in size and contains 25 genes that all encode hypothetical proteins. Notably, PCR assays revealed that Chr14 was absent in 19 out of 24 isolates of a world-wide collection of C. fulvum, indicating that Chr14 is dispensable. Thus, C. fulvum is currently the second species of Capnodiales shown to harbour dispensable chromosomes. The genome of C. fulvum Race 5 is 49.7 % repetitive and contains 14 690 predicted genes with an estimated completeness of 98.9%, currently one of the highest among the Capnodiales. Genome structure analysis revealed a compartmentalized architecture composed of gene-dense and repeat-poor regions interspersed with gene-sparse and repeat-rich regions. Nearly 39.2 % of the C. fulvum Race 5 genome is affected by Repeat-Induced Point (RIP) mutations and evidence of RIP leakage toward non-repetitive regions was observed in all chromosomes, indicating the RIP plays an important role in the evolution of this pathogen. Finally, 345 genes encoding candidate effectors were identified in C. fulvum Race 5, with a significant enrichment of their location in gene-sparse regions, in accordance with the 'two-speed genome' model of evolution. Overall, the new reference genome of C. fulvum presents several notable features and is a valuable resource for studies in plant pathogens.
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Affiliation(s)
- Alex Z. Zaccaron
- Department of Plant Pathology, University of California Davis, Davis, USA
| | - Li-Hung Chen
- Department of Plant Pathology, University of California Davis, Davis, USA
- Present address: Department of Plant Pathology, National Chung Hsing University, Taichung, Taiwan, ROC
| | - Anastasios Samaras
- Department of Plant Pathology, University of California Davis, Davis, USA
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De Miccolis Angelini RM, Landi L, Raguseo C, Pollastro S, Faretra F, Romanazzi G. Tracking of Diversity and Evolution in the Brown Rot Fungi Monilinia fructicola, Monilinia fructigena, and Monilinia laxa. Front Microbiol 2022; 13:854852. [PMID: 35356516 PMCID: PMC8959702 DOI: 10.3389/fmicb.2022.854852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 02/15/2022] [Indexed: 11/13/2022] Open
Abstract
Monilinia species are among the most devastating fungi worldwide as they cause brown rot and blossom blight on fruit trees. To understand the molecular bases of their pathogenic lifestyles, we compared the newly assembled genomes of single strains of Monilinia fructicola, M. fructigena and M. laxa, with those of Botrytis cinerea and Sclerotinia sclerotiorum, as the closest species within Sclerotiniaceae. Phylogenomic analysis of orthologous proteins and syntenic investigation suggest that M. laxa is closer to M. fructigena than M. fructicola, and is closest to the other investigated Sclerotiniaceae species. This indicates that M. laxa was the earliest result of the speciation process. Distinct evolutionary profiles were observed for transposable elements (TEs). M. fructicola and M. laxa showed older bursts of TE insertions, which were affected (mainly in M. fructicola) by repeat-induced point (RIP) mutation gene silencing mechanisms. These suggested frequent occurrence of the sexual process in M. fructicola. More recent TE expansion linked with low RIP action was observed in M. fructigena, with very little in S. sclerotiorum and B. cinerea. The detection of active non-syntenic TEs is indicative of horizontal gene transfer and has resulted in alterations in specific gene functions. Analysis of candidate effectors, biosynthetic gene clusters for secondary metabolites and carbohydrate-active enzymes, indicated that Monilinia genus has multiple virulence mechanisms to infect host plants, including toxins, cell-death elicitor, putative virulence factors and cell-wall-degrading enzymes. Some species-specific pathogenic factors might explain differences in terms of host plant and organ preferences between M. fructigena and the other two Monilinia species.
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Affiliation(s)
| | - Lucia Landi
- Department of Agricultural, Food and Environmental Sciences, Marche Polytechnic University, Ancona, Italy
| | - Celeste Raguseo
- Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Stefania Pollastro
- Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Francesco Faretra
- Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Gianfranco Romanazzi
- Department of Agricultural, Food and Environmental Sciences, Marche Polytechnic University, Ancona, Italy
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Dolatabadian A, Fernando WGD. Genomic Variations and Mutational Events Associated with Plant-Pathogen Interactions. BIOLOGY 2022; 11:421. [PMID: 35336795 PMCID: PMC8945218 DOI: 10.3390/biology11030421] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/07/2022] [Accepted: 03/08/2022] [Indexed: 12/23/2022]
Abstract
Phytopathologists are actively researching the molecular basis of plant-pathogen interactions. The mechanisms of responses to pathogens have been studied extensively in model crop plant species and natural populations. Today, with the rapid expansion of genomic technologies such as DNA sequencing, transcriptomics, proteomics, and metabolomics, as well as the development of new methods and protocols, data analysis, and bioinformatics, it is now possible to assess the role of genetic variation in plant-microbe interactions and to understand the underlying molecular mechanisms of plant defense and microbe pathogenicity with ever-greater resolution and accuracy. Genetic variation is an important force in evolution that enables organisms to survive in stressful environments. Moreover, understanding the role of genetic variation and mutational events is essential for crop breeders to produce improved cultivars. This review focuses on genetic variations and mutational events associated with plant-pathogen interactions and discusses how these genome compartments enhance plants' and pathogens' evolutionary processes.
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Affiliation(s)
- Aria Dolatabadian
- Department of Plant Science, Faculty of Agricultural and Food Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada;
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9
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Vogan AA, Martinossi-Allibert I, Ament-Velásquez SL, Svedberg J, Johannesson H. The spore killers, fungal meiotic driver elements. Mycologia 2022; 114:1-23. [PMID: 35138994 DOI: 10.1080/00275514.2021.1994815] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
During meiosis, both alleles of any given gene should have equal chances of being inherited by the progeny. There are a number of reasons why, however, this is not the case, with one of the most intriguing instances presenting itself as the phenomenon of meiotic drive. Genes that are capable of driving can manipulate the ratio of alleles among viable meiotic products so that they are inherited in more than half of them. In many cases, this effect is achieved by direct antagonistic interactions, where the driving allele inhibits or otherwise eliminates the alternative allele. In ascomycete fungi, meiotic products are packaged directly into ascospores; thus, the effect of meiotic drive has been given the nefarious moniker, "spore killing." In recent years, many of the known spore killers have been elevated from mysterious phenotypes to well-described systems at genetic, genomic, and molecular levels. In this review, we describe the known diversity of spore killers and synthesize the varied pieces of data from each system into broader trends regarding genome architecture, mechanisms of resistance, the role of transposable elements, their effect on population dynamics, speciation and gene flow, and finally how they may be developed as synthetic drivers. We propose that spore killing is common, but that it is under-observed because of a lack of studies on natural populations. We encourage researchers to seek new spore killers to build on the knowledge that these remarkable genetic elements can teach us about meiotic drive, genomic conflict, and evolution more broadly.
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Affiliation(s)
- Aaron A Vogan
- Systematic Biology, Department of Organismal Biology, Uppsala University, 752 36, Uppsala, Sweden
| | - Ivain Martinossi-Allibert
- Systematic Biology, Department of Organismal Biology, Uppsala University, 752 36, Uppsala, Sweden.,Institut de Biochimie et de Génétique Cellulaire, UMR 5095 CNRS, Université de Bordeaux, 33077, Bordeaux CEDEX, France
| | - S Lorena Ament-Velásquez
- Systematic Biology, Department of Organismal Biology, Uppsala University, 752 36, Uppsala, Sweden
| | - Jesper Svedberg
- Department of Biomolecular Engineering, University of California, -Santa Cruz, Santa Cruz, California 95064
| | - Hanna Johannesson
- Systematic Biology, Department of Organismal Biology, Uppsala University, 752 36, Uppsala, Sweden
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10
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Nagel JH, Wingfield MJ, Slippers B. Next-generation sequencing provides important insights into the biology and evolution of the Botryosphaeriaceae. FUNGAL BIOL REV 2021. [DOI: 10.1016/j.fbr.2021.09.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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11
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Treindl AD, Stapley J, Winter DJ, Cox MP, Leuchtmann A. Chromosome-level genomes provide insights into genome evolution, organization and size in Epichloe fungi. Genomics 2021; 113:4267-4275. [PMID: 34774981 DOI: 10.1016/j.ygeno.2021.11.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 10/21/2021] [Accepted: 11/08/2021] [Indexed: 01/10/2023]
Abstract
Epichloe fungi are endophytes of cool season grasses, both wild species and commercial cultivars, where they may exhibit mutualistic or pathogenic lifestyles. The Epichloe-grass symbiosis is of great interest to agricultural research for the fungal bioprotective properties conferred to host grasses but also serves as an ideal system to study the evolution of fungal plant-pathogens in natural environments. Here, we assembled and annotated gapless chromosome-level genomes of two pathogenic Epichloe sibling species. Both genomes have a bipartite genome organization, with blocks of highly syntenic gene-rich regions separated by blocks of AT-rich DNA. The AT-rich regions show an extensive signature of RIP (repeat-induced point mutation) and the expansion of this compartment accounts for the large difference in genome size between the two species. This study reveals how the rapid evolution of repeat structure can drive divergence between closely related taxa and highlights the evolutionary role of dynamic compartments in fungal genomes.
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Affiliation(s)
- Artemis D Treindl
- Plant Ecological Genetics Group, Institute of Integrative Biology, ETH Zurich, 8092 Zurich, Switzerland.
| | - Jessica Stapley
- Plant Ecological Genetics Group, Institute of Integrative Biology, ETH Zurich, 8092 Zurich, Switzerland
| | - David J Winter
- Statistics and Bioinformatics Group, School of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand
| | - Murray P Cox
- Statistics and Bioinformatics Group, School of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand
| | - Adrian Leuchtmann
- Plant Ecological Genetics Group, Institute of Integrative Biology, ETH Zurich, 8092 Zurich, Switzerland
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12
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Zhang Z, He C, Chen Y, Li B, Tian S. DNA Methyltransferases Regulate Pathogenicity of Botrytis cinerea to Horticultural Crops. J Fungi (Basel) 2021; 7:jof7080659. [PMID: 34436198 PMCID: PMC8399656 DOI: 10.3390/jof7080659] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 08/05/2021] [Accepted: 08/09/2021] [Indexed: 11/18/2022] Open
Abstract
Botrytis cinerea is one of the most destructive fungal pathogens that cause gray mold rot in horticultural products, including fresh fruits, vegetables, and flowers, leading to serious economic losses. B. cinerea is difficult to control because it has strong stress resistance and complex infection modes. The pathogenic mechanisms of B. cinerea have been revealed at multiple levels, but little is known at the epigenetic level. In this study, we first revealed the important role of DNA methyltransferases in regulating the development and pathogenicity of B. cinerea. We showed that two DNA methyltransferases, BcDIM2 and BcRID2, showed a strong synergistic effect in regulating the pathogenicity of B. cinerea. The double knockout mutant ΔBcdim2rid2 showed slower mycelial growth, lower spore germination, attenuated oxidative tolerance, and complete pathogenicity loss on various hosts, which is related to the reduced expression of virulence-related genes in ΔBcdim2rid2 and the induced resistance of the host. Although B. cinerea has multiple DNA methyltransferases, the global methylation level is very low, and few 5mC sites can be detected by BS-seq. These results first revealed the important role and the action mode of DNA methyltransferases in B. cinerea.
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Affiliation(s)
- Zhanquan Zhang
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; (Z.Z.); (C.H.); (Y.C.); (B.L.)
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chang He
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; (Z.Z.); (C.H.); (Y.C.); (B.L.)
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yong Chen
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; (Z.Z.); (C.H.); (Y.C.); (B.L.)
| | - Boqiang Li
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; (Z.Z.); (C.H.); (Y.C.); (B.L.)
| | - Shiping Tian
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; (Z.Z.); (C.H.); (Y.C.); (B.L.)
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Correspondence:
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13
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Torres DE, Thomma BPHJ, Seidl MF. Transposable Elements Contribute to Genome Dynamics and Gene Expression Variation in the Fungal Plant Pathogen Verticillium dahliae. Genome Biol Evol 2021; 13:evab135. [PMID: 34100895 PMCID: PMC8290119 DOI: 10.1093/gbe/evab135] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/04/2021] [Indexed: 12/12/2022] Open
Abstract
Transposable elements (TEs) are a major source of genetic and regulatory variation in their host genome and are consequently thought to play important roles in evolution. Many fungal and oomycete plant pathogens have evolved dynamic and TE-rich genomic regions containing genes that are implicated in host colonization and adaptation. TEs embedded in these regions have typically been thought to accelerate the evolution of these genomic compartments, but little is known about their dynamics in strains that harbor them. Here, we used whole-genome sequencing data of 42 strains of the fungal plant pathogen Verticillium dahliae to systematically identify polymorphic TEs that may be implicated in genomic as well as in gene expression variation. We identified 2,523 TE polymorphisms and characterize a subset of 8% of the TEs as polymorphic elements that are evolutionary younger, less methylated, and more highly expressed when compared with the remaining 92% of the total TE complement. As expected, the polyrmorphic TEs are enriched in the adaptive genomic regions. Besides, we observed an association of polymorphic TEs with pathogenicity-related genes that localize nearby and that display high expression levels. Collectively, our analyses demonstrate that TE dynamics in V. dahliae contributes to genomic variation, correlates with expression of pathogenicity-related genes, and potentially impacts the evolution of adaptive genomic regions.
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Affiliation(s)
- David E Torres
- Theoretical Biology and Bioinformatics Group, Department of Biology, Utrecht University, The Netherlands
- Laboratory of Phytopathology, Wageningen University and Research, The Netherlands
| | - Bart P H J Thomma
- Laboratory of Phytopathology, Wageningen University and Research, The Netherlands
- Cluster of Excellence on Plant Sciences (CEPLAS), Institute for Plant Sciences, University of Cologne, Germany
| | - Michael F Seidl
- Theoretical Biology and Bioinformatics Group, Department of Biology, Utrecht University, The Netherlands
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14
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Elfstrand M, Chen J, Cleary M, Halecker S, Ihrmark K, Karlsson M, Davydenko K, Stenlid J, Stadler M, Durling MB. Comparative analyses of the Hymenoscyphus fraxineus and Hymenoscyphus albidus genomes reveals potentially adaptive differences in secondary metabolite and transposable element repertoires. BMC Genomics 2021; 22:503. [PMID: 34217229 PMCID: PMC8254937 DOI: 10.1186/s12864-021-07837-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 06/24/2021] [Indexed: 11/29/2022] Open
Abstract
Background The dieback epidemic decimating common ash (Fraxinus excelsior) in Europe is caused by the invasive fungus Hymenoscyphus fraxineus. In this study we analyzed the genomes of H. fraxineus and H. albidus, its native but, now essentially displaced, non-pathogenic sister species, and compared them with several other members of Helotiales. The focus of the analyses was to identify signals in the genome that may explain the rapid establishment of H. fraxineus and displacement of H. albidus. Results The genomes of H. fraxineus and H. albidus showed a high level of synteny and identity. The assembly of H. fraxineus is 13 Mb longer than that of H. albidus’, most of this difference can be attributed to higher dispersed repeat content (i.e. transposable elements [TEs]) in H. fraxineus. In general, TE families in H. fraxineus showed more signals of repeat-induced point mutations (RIP) than in H. albidus, especially in Long-terminal repeat (LTR)/Copia and LTR/Gypsy elements. Comparing gene family expansions and 1:1 orthologs, relatively few genes show signs of positive selection between species. However, several of those did appeared to be associated with secondary metabolite genes families, including gene families containing two of the genes in the H. fraxineus-specific, hymenosetin biosynthetic gene cluster (BGC). Conclusion The genomes of H. fraxineus and H. albidus show a high degree of synteny, and are rich in both TEs and BGCs, but the genomic signatures also indicated that H. albidus may be less well equipped to adapt and maintain its ecological niche in a rapidly changing environment. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-07837-2.
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Affiliation(s)
- Malin Elfstrand
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Almas Allé 5, Box 7026, SE-750 07, Uppsala, Sweden.
| | - Jun Chen
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Almas Allé 5, Box 7026, SE-750 07, Uppsala, Sweden.,Systematic & Evolutionary Botany and Biodiversity group, MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Michelle Cleary
- Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, Sundsvägen 3, Box 49, SE-230 53, Alnarp, Sweden
| | - Sandra Halecker
- Dept. Microbial Drugs, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, D-38124, Braunschweig, Germany
| | - Katarina Ihrmark
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Almas Allé 5, Box 7026, SE-750 07, Uppsala, Sweden
| | - Magnus Karlsson
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Almas Allé 5, Box 7026, SE-750 07, Uppsala, Sweden
| | - Kateryna Davydenko
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Almas Allé 5, Box 7026, SE-750 07, Uppsala, Sweden.,Ukrainian research Institute of Forestry and Forest Melioration, 62458, Kharkov, Ukraine
| | - Jan Stenlid
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Almas Allé 5, Box 7026, SE-750 07, Uppsala, Sweden
| | - Marc Stadler
- Dept. Microbial Drugs, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, D-38124, Braunschweig, Germany
| | - Mikael Brandström Durling
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Almas Allé 5, Box 7026, SE-750 07, Uppsala, Sweden
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15
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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: 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: 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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16
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Biocatalytic potential of basidiomycetes: Relevance, challenges and research interventions in industrial processes. SCIENTIFIC AFRICAN 2021. [DOI: 10.1016/j.sciaf.2021.e00717] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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17
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Distinct Roles of Two DNA Methyltransferases from Cryphonectria parasitica in Fungal Virulence, Responses to Hypovirus Infection, and Viral Clearance. mBio 2021; 12:mBio.02890-20. [PMID: 33563819 PMCID: PMC8545091 DOI: 10.1128/mbio.02890-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Two DNA methyltransferase (DNMTase) genes from Cryphonectria parasitica have been previously identified as CpDmt1 and CpDmt2, which are orthologous to rid and dim-2 of Neurospora crassa, respectively. While global changes in DNA methylation have been associated with fungal sectorization and CpDmt1 but not CpDmt2 has been implicated in the sporadic sectorization, the present study continues to investigate the biological functions of both DNMTase genes. Transcription of both DNMTases is regulated in response to infection with the Cryphonectria hypovirus 1 (CHV1-EP713). CpDmt1 is upregulated and CpDmt2 is downregulated by CHV1 infection. Conidium production and response to heat stress are affected only by mutation of CpDmt1, not by CpDmt2 mutation. Significant changes in virulence are observed in opposite directions; i.e., the CpDmt1-null mutant is hypervirulent, while the CpDmt2-null mutant is hypovirulent. Compared to the CHV1-infected wild type, CHV1-transferred single and double mutants show severe growth retardation: the colony size is less than 10% that of the parental virus-free null mutants, and their titers of transferred CHV1 are higher than that of the wild type, implying that no defect in viral replication occurs. However, as cultivation proceeds, spontaneous viral clearance is observed in hypovirus-infected colonies of the null mutants, which has never been reported in this fungus-virus interaction. This study demonstrates that both DNMTases are significant factors in fungal development and virulence. Each fungal DNMTase affects fungal biology in both common and separate ways. In addition, both genes are essential to the antiviral responses, including viral clearance which depends on their mutations.
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18
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van Wyk S, Wingfield BD, De Vos L, van der Merwe NA, Steenkamp ET. Genome-Wide Analyses of Repeat-Induced Point Mutations in the Ascomycota. Front Microbiol 2021; 11:622368. [PMID: 33597932 PMCID: PMC7882544 DOI: 10.3389/fmicb.2020.622368] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 12/29/2020] [Indexed: 11/17/2022] Open
Abstract
The Repeat-Induced Point (RIP) mutation pathway is a fungus-specific genome defense mechanism that mitigates the deleterious consequences of repeated genomic regions and transposable elements (TEs). RIP mutates targeted sequences by introducing cytosine to thymine transitions. We investigated the genome-wide occurrence and extent of RIP with a sliding-window approach. Using genome-wide RIP data and two sets of control groups, the association between RIP, TEs, and GC content were contrasted in organisms capable and incapable of RIP. Based on these data, we then set out to determine the extent and occurrence of RIP in 58 representatives of the Ascomycota. The findings were summarized by placing each of the fungi investigated in one of six categories based on the extent of genome-wide RIP. In silico RIP analyses, using a sliding-window approach with stringent RIP parameters, implemented simultaneously within the same genetic context, on high quality genome assemblies, yielded superior results in determining the genome-wide RIP among the Ascomycota. Most Ascomycota had RIP and these mutations were particularly widespread among classes of the Pezizomycotina, including the early diverging Orbiliomycetes and the Pezizomycetes. The most extreme cases of RIP were limited to representatives of the Dothideomycetes and Sordariomycetes. By contrast, the genomes of the Taphrinomycotina and Saccharomycotina contained no detectable evidence of RIP. Also, recent losses in RIP combined with controlled TE proliferation in the Pezizomycotina subphyla may promote substantial genome enlargement as well as the formation of sub-genomic compartments. These findings have broadened our understanding of the taxonomic range and extent of RIP in Ascomycota and how this pathway affects the genomes of fungi harboring it.
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Affiliation(s)
| | | | | | | | - Emma T. Steenkamp
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
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19
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Crouch JA, Dawe A, Aerts A, Barry K, Churchill ACL, Grimwood J, Hillman BI, Milgroom MG, Pangilinan J, Smith M, Salamov A, Schmutz J, Yadav JS, Grigoriev IV, Nuss DL. Genome Sequence of the Chestnut Blight Fungus Cryphonectria parasitica EP155: A Fundamental Resource for an Archetypical Invasive Plant Pathogen. PHYTOPATHOLOGY 2020; 110:1180-1188. [PMID: 32207662 DOI: 10.1094/phyto-12-19-0478-a] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Cryphonectria parasitica is the causal agent of chestnut blight, a fungal disease that almost entirely eliminated mature American chestnut from North America over a 50-year period. Here, we formally report the genome of C. parasitica EP155 using a Sanger shotgun sequencing approach. After finishing and integration with simple-sequence repeat markers, the assembly was 43.8 Mb in 26 scaffolds (L50 = 5; N50 = 4.0Mb). Eight chromosomes are predicted: five scaffolds have two telomeres and six scaffolds have one telomere sequence. In total, 11,609 gene models were predicted, of which 85% show similarities to other proteins. This genome resource has already increased the utility of a fundamental plant pathogen experimental system through new understanding of the fungal vegetative incompatibility system, with significant implications for enhancing mycovirus-based biological control.
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Affiliation(s)
- Jo Anne Crouch
- Mycology and Nematology Genetic Diversity and Biology Laboratory, United States Department of Agriculture-Agricultural Research Service, 10300 Baltimore Avenue, Building 010A, Beltsville, MD, U.S.A
| | - Angus Dawe
- Department of Biological Sciences, Mississippi State University, 295 Lee Boulevard, Mississippi State, MS, U.S.A
| | - Andrea Aerts
- United States Department of Energy Joint Genome Institute, Walnut Creek, CA, U.S.A
| | - Kerrie Barry
- United States Department of Energy Joint Genome Institute, Walnut Creek, CA, U.S.A
| | - Alice C L Churchill
- School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology Section, Cornell University, Ithaca, NY, U.S.A
| | - Jane Grimwood
- HudsonAlpha Institute for Biotechnology, Huntsville, AL, U.S.A
| | - Bradley I Hillman
- Department of Plant Biology, Rutgers University, 59 Dudley Road, New Brunswick, NJ, U.S.A
| | - Michael G Milgroom
- School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology Section, Cornell University, Ithaca, NY, U.S.A
| | - Jasmyn Pangilinan
- United States Department of Energy Joint Genome Institute, Walnut Creek, CA, U.S.A
| | - Myron Smith
- Department of Biology, Carleton University, 1125 Colonel by Drive, Ottawa, ON, Canada
| | - Asaf Salamov
- United States Department of Energy Joint Genome Institute, Walnut Creek, CA, U.S.A
| | - Jeremy Schmutz
- United States Department of Energy Joint Genome Institute, Walnut Creek, CA, U.S.A
- HudsonAlpha Institute for Biotechnology, Huntsville, AL, U.S.A
| | - Jagjit S Yadav
- Environmental Genetics and Molecular Toxicology Division, Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, OH, U.S.A
| | - Igor V Grigoriev
- HudsonAlpha Institute for Biotechnology, Huntsville, AL, U.S.A
- Department of Plant and Microbial Biology, University of California Berkeley, Berkeley, CA, U.S.A
| | - Donald L Nuss
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, U.S.A
- Division of Plant and Soil Sciences, West Virginia University, Morgantown, WV, U.S.A
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20
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da Silva LL, Moreno HLA, Correia HLN, Santana MF, de Queiroz MV. Colletotrichum: species complexes, lifestyle, and peculiarities of some sources of genetic variability. Appl Microbiol Biotechnol 2020; 104:1891-1904. [PMID: 31932894 DOI: 10.1007/s00253-020-10363-y] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/30/2019] [Accepted: 01/09/2020] [Indexed: 11/25/2022]
Abstract
The genus Colletotrichum comprises species with different lifestyles but is mainly known for phytopathogenic species that infect crops of agronomic relevance causing considerable losses. The fungi of the genus Colletotrichum are distributed in species complexes and within each complex some species have particularities regarding their lifestyle. The most commonly found and described lifestyles in Colletotrichum are endophytic and hemibiotrophic phytopathogenic. Several of these phytopathogenic species show wide genetic variability, which makes long-term maintenance of resistance in plants difficult. Different mechanisms may play an important role in the emergence of genetic variants but are not yet fully understood in this genus. These mechanisms include heterokaryosis, a parasexual cycle, sexual cycle, transposable element activity, and repeat-induced point mutations. This review provides an overview of the genus Colletotrichum, the species complexes described so far and the most common lifestyles in the genus, with a special emphasis on the mechanisms that may be responsible, at least in part, for the emergence of new genotypes under field conditions.
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Affiliation(s)
- Leandro Lopes da Silva
- Laboratório de Genética Molecular de Fungos, Departamento de Microbiologia/Instituto de Biotecnologia Aplicada à Agropecuária (BIOAGRO), Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Hanna Lorena Alvarado Moreno
- Laboratório de Genética Molecular de Fungos, Departamento de Microbiologia/Instituto de Biotecnologia Aplicada à Agropecuária (BIOAGRO), Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Hilberty Lucas Nunes Correia
- Laboratório de Genética Molecular de Fungos, Departamento de Microbiologia/Instituto de Biotecnologia Aplicada à Agropecuária (BIOAGRO), Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Mateus Ferreira Santana
- Laboratório de Genética Molecular de Fungos, Departamento de Microbiologia/Instituto de Biotecnologia Aplicada à Agropecuária (BIOAGRO), Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Marisa Vieira de Queiroz
- Laboratório de Genética Molecular de Fungos, Departamento de Microbiologia/Instituto de Biotecnologia Aplicada à Agropecuária (BIOAGRO), Universidade Federal de Viçosa, Viçosa, MG, Brazil.
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21
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22
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Rajarammohan S, Paritosh K, Pental D, Kaur J. Comparative genomics of Alternaria species provides insights into the pathogenic lifestyle of Alternaria brassicae - a pathogen of the Brassicaceae family. BMC Genomics 2019; 20:1036. [PMID: 31888481 PMCID: PMC6937934 DOI: 10.1186/s12864-019-6414-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 12/19/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Alternaria brassicae, a necrotrophic pathogen, causes Alternaria Leaf Spot, one of the economically important diseases of Brassica crops. Many other Alternaria spp. such as A. brassicicola and A. alternata are known to cause secondary infections in the A. brassicae-infected Brassicas. The genome architecture, pathogenicity factors, and determinants of host-specificity of A. brassicae are unknown. In this study, we annotated and characterised the recently announced genome assembly of A. brassicae and compared it with other Alternaria spp. to gain insights into its pathogenic lifestyle. RESULTS We also sequenced the genomes of two A. alternata isolates that were co-infecting B. juncea using Nanopore MinION sequencing for additional comparative analyses within the Alternaria genus. Genome alignments within the Alternaria spp. revealed high levels of synteny between most chromosomes with some intrachromosomal rearrangements. We show for the first time that the genome of A. brassicae, a large-spored Alternaria species, contains a dispensable chromosome. We identified 460 A. brassicae-specific genes, which included many secreted proteins and effectors. Furthermore, we have identified the gene clusters responsible for the production of Destruxin-B, a known pathogenicity factor of A. brassicae. CONCLUSION The study provides a perspective into the unique and shared repertoire of genes within the Alternaria genus and identifies genes that could be contributing to the pathogenic lifestyle of A. brassicae.
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Affiliation(s)
- Sivasubramanian Rajarammohan
- Department of Genetics, University of Delhi , South Campus, New Delhi, 110021, India
- Present Address: National Agri-Food Biotechnology Institute, Mohali, India
| | - Kumar Paritosh
- Centre for Genetic Manipulation of Crop Plants, University of Delhi South Campus, New Delhi, India
| | - Deepak Pental
- Centre for Genetic Manipulation of Crop Plants, University of Delhi South Campus, New Delhi, India
| | - Jagreet Kaur
- Department of Genetics, University of Delhi , South Campus, New Delhi, 110021, India.
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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: 7] [Impact Index Per Article: 1.4] [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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van Wyk S, Harrison CH, Wingfield BD, De Vos L, van der Merwe NA, Steenkamp ET. The RIPper, a web-based tool for genome-wide quantification of Repeat-Induced Point (RIP) mutations. PeerJ 2019; 7:e7447. [PMID: 31523495 PMCID: PMC6714961 DOI: 10.7717/peerj.7447] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 07/09/2019] [Indexed: 12/24/2022] Open
Abstract
Background The RIPper (http://theripper.hawk.rocks) is a set of web-based tools designed for analyses of Repeat-Induced Point (RIP) mutations in the genome sequences of Ascomycota. The RIP pathway is a fungal genome defense mechanism that is aimed at identifying repeated and duplicated motifs, into which it then introduces cytosine to thymine transition mutations. RIP thus serves to deactivate and counteract the deleterious consequences of selfish or mobile DNA elements in fungal genomes. The occurrence, genetic context and frequency of RIP mutations are widely used to assess the activity of this pathway in genomic regions of interest. Here, we present a bioinformatics tool that is specifically fashioned to automate the investigation of changes in RIP product and substrate nucleotide frequencies in fungal genomes. Results We demonstrated the ability of The RIPper to detect the occurrence and extent of RIP mutations in known RIP affected sequences. Specifically, a sliding window approach was used to perform genome-wide RIP analysis on the genome assembly of Neurospora crassa. Additionally, fine-scale analysis with The RIPper showed that gene regions and transposable element sequences, previously determined to be affected by RIP, were indeed characterized by high frequencies of RIP mutations. Data generated using this software further showed that large proportions of the N. crassa genome constitutes RIP mutations with extensively affected regions displaying reduced GC content. The RIPper was further useful for investigating and visualizing changes in RIP mutations across the length of sequences of interest, allowing for fine-scale analyses. Conclusion This software identified RIP targeted genomic regions and provided RIP statistics for an entire genome assembly, including the genomic proportion affected by RIP. Here, we present The RIPper as an efficient tool for genome-wide RIP analyses.
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Affiliation(s)
- Stephanie van Wyk
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, Gauteng, South Africa
| | - Christopher H Harrison
- Department of product and software development, Amplo PTY, Pretoria, Gauteng, South Africa
| | - Brenda D Wingfield
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, Gauteng, South Africa
| | - Lieschen De Vos
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, Gauteng, South Africa
| | - Nicolaas A van der Merwe
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, Gauteng, South Africa
| | - Emma T Steenkamp
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, Gauteng, South Africa
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Schmitz RJ, Lewis ZA, Goll MG. DNA Methylation: Shared and Divergent Features across Eukaryotes. Trends Genet 2019; 35:818-827. [PMID: 31399242 DOI: 10.1016/j.tig.2019.07.007] [Citation(s) in RCA: 127] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/01/2019] [Accepted: 07/15/2019] [Indexed: 02/02/2023]
Abstract
Chemical modification of nucleotide bases in DNA provides one mechanism for conveying information in addition to the genetic code. 5-methylcytosine (5mC) represents the most common chemically modified base in eukaryotic genomes. Sometimes referred to simply as DNA methylation, in eukaryotes 5mC is most prevalent at CpG dinucleotides and is frequently associated with transcriptional repression of transposable elements. However, 5mC levels and distributions are variable across phylogenies, and emerging evidence suggests that the functions of DNA methylation may be more diverse and complex than was previously appreciated. We summarize the current understanding of DNA methylation profiles and functions in different eukaryotic lineages.
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Affiliation(s)
- Robert J Schmitz
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
| | - Zachary A Lewis
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
| | - Mary G Goll
- Department of Genetics, University of Georgia, Athens, GA 30602, USA.
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Muszewska A, Steczkiewicz K, Stepniewska-Dziubinska M, Ginalski K. Transposable elements contribute to fungal genes and impact fungal lifestyle. Sci Rep 2019; 9:4307. [PMID: 30867521 PMCID: PMC6416283 DOI: 10.1038/s41598-019-40965-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 02/26/2019] [Indexed: 12/21/2022] Open
Abstract
The last decade brought a still growing experimental evidence of mobilome impact on host's gene expression. We systematically analysed genomic location of transposable elements (TEs) in 625 publicly available fungal genomes from the NCBI database in order to explore their potential roles in genome evolution and correlation with species' lifestyle. We found that non-autonomous TEs and remnant copies are evenly distributed across genomes. In consequence, they also massively overlap with regions annotated as genes, which suggests a great contribution of TE-derived sequences to host's coding genome. Younger and potentially active TEs cluster with one another away from genic regions. This non-randomness is a sign of either selection against insertion of TEs in gene proximity or target site preference among some types of TEs. Proteins encoded by genes with old transposable elements insertions have significantly less repeat and protein-protein interaction motifs but are richer in enzymatic domains. However, genes only proximal to TEs do not display any functional enrichment. Our findings show that adaptive cases of TE insertion remain a marginal phenomenon, and the overwhelming majority of TEs are evolving neutrally. Eventually, animal-related and pathogenic fungi have more TEs inserted into genes than fungi with other lifestyles. This is the first systematic, kingdom-wide study concerning mobile elements and their genomic neighbourhood. The obtained results should inspire further research concerning the roles TEs played in evolution and how they shape the life we know today.
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Affiliation(s)
- Anna Muszewska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106, Warsaw, Poland.
| | - Kamil Steczkiewicz
- Laboratory of Bioinformatics and Systems Biology, CeNT, University of Warsaw, Zwirki i Wigury 93, 02-089, Warsaw, Poland
| | | | - Krzysztof Ginalski
- Laboratory of Bioinformatics and Systems Biology, CeNT, University of Warsaw, Zwirki i Wigury 93, 02-089, Warsaw, Poland
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Valero-Jiménez CA, Veloso J, Staats M, van Kan JAL. Comparative genomics of plant pathogenic Botrytis species with distinct host specificity. BMC Genomics 2019; 20:203. [PMID: 30866801 PMCID: PMC6417074 DOI: 10.1186/s12864-019-5580-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 03/03/2019] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Fungi of the genus Botrytis (presently containing ~ 35 species) are able to infect more than 1400 different plant species and cause losses in a wide range of crops of economic importance. The best studied species is B. cinerea, which has a broad host range and is one of the best studied necrotrophic plant pathogenic fungi. Most other Botrytis spp. have a narrow host range and have been studied in less detail. To characterize genomic variation among different representatives of Botrytis spp., we sequenced and annotated the draft genomes of nine Botrytis species: B. calthae, B. convoluta, B. elliptica, B. galanthina, B. hyacinthi, B. narcissicola, B. paeoniae, B. porri and B. tulipae. RESULTS Bioinformatics and comparative genomics tools were applied to determine a core of 7668 shared protein families in all Botrytis species, which grouped them in two distinct phylogenetic clades. The secretome of all nine Botrytis spp. was similar in number (ranging from 716 to 784 predicted proteins). A detailed analysis of the molecular functions of the secretome revealed that shared activities were highly similar. Orthologs to effectors functionally studied in B. cinerea were also present in the other Botrytis species. A complex pattern of presence/absence of secondary metabolite biosynthetic key enzymes was observed. CONCLUSIONS Comparative genomics of Botrytis show that overall, species share the main signatures and protein families in the secreted proteins, and of known effectors. Our study provides leads to study host range determinants in the genus Botrytis and provides a stepping stone to elucidate the roles of effector candidates in the infection process of these species.
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Affiliation(s)
| | - Javier Veloso
- Laboratory of Phytopathology, Wageningen University, 6708PB Wageningen, the Netherlands
- Department of Biology, Faculty of Sciences, University of A Coruña, A Coruña, Spain
| | - Martijn Staats
- Biosystematics Group, Wageningen University, 6708PB Wageningen, the Netherlands
- Present address: RIKILT Wageningen University and Research, 6708WB Wageningen, the Netherlands
| | - Jan A. L. van Kan
- Laboratory of Phytopathology, Wageningen University, 6708PB Wageningen, the Netherlands
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Van de Wouw AP, Elliott CE, Popa KM, Idnurm A. Analysis of Repeat Induced Point (RIP) Mutations in Leptosphaeria maculans Indicates Variability in the RIP Process Between Fungal Species. Genetics 2019; 211:89-104. [PMID: 30389803 PMCID: PMC6325690 DOI: 10.1534/genetics.118.301712] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 10/24/2018] [Indexed: 01/01/2023] Open
Abstract
Gene duplication contributes to evolutionary potential, yet many duplications in a genome arise from the activity of "selfish" genetic elements such as transposable elements. Fungi have a number of mechanisms by which they limit the expansion of transposons, including Repeat Induced Point mutation (RIP). RIP has been best characterized in the Sordariomycete Neurospora crassa, wherein duplicated DNA regions are recognized after cell fusion, but before nuclear fusion during the sexual cycle, and then mutated. While "signatures" of RIP appear in the genome sequences of many fungi, the species most distant from N. crassa in which the process has been experimentally demonstrated to occur is the Dothideomycete Leptosphaeria maculans In the current study, we show that similar to N. crassa, nonlinked duplications can trigger RIP; however, the frequency of the generated RIP mutations is extremely low in L maculans (< 0.1%) and requires a large duplication to initiate RIP, and that multiple premeiotic mitoses are involved in the RIP process. However, a single sexual cycle leads to the generation of progeny with unique haplotypes, despite progeny pairs being generated from mitosis. We hypothesize that these different haplotypes may be the result of the deamination process occurring post karyogamy, leading to unique mutations within each of the progeny pairs. These findings indicate that the RIP process, while common to many fungi, differs between fungi and that this impacts on the fate of duplicated DNA.
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Affiliation(s)
- Angela P Van de Wouw
- School of BioSciences, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Candace E Elliott
- School of BioSciences, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Kerryn M Popa
- School of BioSciences, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Alexander Idnurm
- School of BioSciences, The University of Melbourne, Parkville, Victoria 3010, Australia
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Murat C, Payen T, Noel B, Kuo A, Morin E, Chen J, Kohler A, Krizsán K, Balestrini R, Da Silva C, Montanini B, Hainaut M, Levati E, Barry KW, Belfiori B, Cichocki N, Clum A, Dockter RB, Fauchery L, Guy J, Iotti M, Le Tacon F, Lindquist EA, Lipzen A, Malagnac F, Mello A, Molinier V, Miyauchi S, Poulain J, Riccioni C, Rubini A, Sitrit Y, Splivallo R, Traeger S, Wang M, Žifčáková L, Wipf D, Zambonelli A, Paolocci F, Nowrousian M, Ottonello S, Baldrian P, Spatafora JW, Henrissat B, Nagy LG, Aury JM, Wincker P, Grigoriev IV, Bonfante P, Martin FM. Pezizomycetes genomes reveal the molecular basis of ectomycorrhizal truffle lifestyle. Nat Ecol Evol 2018; 2:1956-1965. [DOI: 10.1038/s41559-018-0710-4] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 10/04/2018] [Indexed: 11/09/2022]
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Wu Y, Ma X, Pan Z, Kale SD, Song Y, King H, Zhang Q, Presley C, Deng X, Wei CI, Xiao S. Comparative genome analyses reveal sequence features reflecting distinct modes of host-adaptation between dicot and monocot powdery mildew. BMC Genomics 2018; 19:705. [PMID: 30253736 PMCID: PMC6156980 DOI: 10.1186/s12864-018-5069-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 09/11/2018] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Powdery mildew (PM) is one of the most important and widespread plant diseases caused by biotrophic fungi. Notably, while monocot (grass) PM fungi exhibit high-level of host-specialization, many dicot PM fungi display a broad host range. To understand such distinct modes of host-adaptation, we sequenced the genomes of four dicot PM biotypes belonging to Golovinomyces cichoracearum or Oidium neolycopersici. RESULTS We compared genomes of the four dicot PM together with those of Blumeria graminis f.sp. hordei (both DH14 and RACE1 isolates), B. graminis f.sp. tritici, and Erysiphe necator infectious on barley, wheat and grapevine, respectively. We found that despite having a similar gene number (6620-6961), the PM genomes vary from 120 to 222 Mb in size. This high-level of genome size variation is indicative of highly differential transposon activities in the PM genomes. While the total number of genes in any given PM genome is only about half of that in the genomes of closely related ascomycete fungi, most (~ 93%) of the ascomycete core genes (ACGs) can be found in the PM genomes. Yet, 186 ACGs were found absent in at least two of the eight PM genomes, of which 35 are missing in some dicot PM biotypes, but present in the three monocot PM genomes, indicating remarkable, independent and perhaps ongoing gene loss in different PM lineages. Consistent with this, we found that only 4192 (3819 singleton) genes are shared by all the eight PM genomes, the remaining genes are lineage- or biotype-specific. Strikingly, whereas the three monocot PM genomes possess up to 661 genes encoding candidate secreted effector proteins (CSEPs) with families containing up to 38 members, all the five dicot PM fungi have only 116-175 genes encoding CSEPs with limited gene amplification. CONCLUSIONS Compared to monocot (grass) PM fungi, dicot PM fungi have a much smaller effectorome. This is consistent with their contrasting modes of host-adaption: while the monocot PM fungi show a high-level of host specialization, which may reflect an advanced host-pathogen arms race, the dicot PM fungi tend to practice polyphagy, which might have lessened selective pressure for escalating an with a particular host.
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Affiliation(s)
- Ying Wu
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD 20850 USA
| | - Xianfeng Ma
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD 20850 USA
- Hunan Provincial Key Laboratory for Germplasm Innovation and Utilization of Crop, Hunan Agricultural University, Changsha, 410128 China
| | - Zhiyong Pan
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Key Laboratory of Horticultural Crop Biology and Genetic Improvement (Central Region, Ministry of Agriculture), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070 China
| | - Shiv D. Kale
- Biocomplexity Institute, Virginia Tech, Blacksburg, VA 24061 USA
| | - Yi Song
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD 20850 USA
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083 China
| | - Harlan King
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD 20850 USA
| | - Qiong Zhang
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD 20850 USA
| | - Christian Presley
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD 20850 USA
| | - Xiuxin Deng
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Key Laboratory of Horticultural Crop Biology and Genetic Improvement (Central Region, Ministry of Agriculture), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070 China
| | - Cheng-I Wei
- College of Agriculture & Natural Resources, University of Maryland, College Park, MD 20742 USA
| | - Shunyuan Xiao
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD 20850 USA
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD 20742 USA
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Syme RA, Tan KC, Rybak K, Friesen TL, McDonald BA, Oliver RP, Hane JK. Pan-Parastagonospora Comparative Genome Analysis-Effector Prediction and Genome Evolution. Genome Biol Evol 2018; 10:2443-2457. [PMID: 30184068 PMCID: PMC6152946 DOI: 10.1093/gbe/evy192] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2018] [Indexed: 01/01/2023] Open
Abstract
We report a fungal pan-genome study involving Parastagonospora spp., including 21 isolates of the wheat (Triticum aestivum) pathogen Parastagonospora nodorum, 10 of the grass-infecting Parastagonospora avenae, and 2 of a closely related undefined sister species. We observed substantial variation in the distribution of polymorphisms across the pan-genome, including repeat-induced point mutations, diversifying selection and gene gains and losses. We also discovered chromosome-scale inter and intraspecific presence/absence variation of some sequences, suggesting the occurrence of one or more accessory chromosomes or regions that may play a role in host-pathogen interactions. The presence of known pathogenicity effector loci SnToxA, SnTox1, and SnTox3 varied substantially among isolates. Three P. nodorum isolates lacked functional versions for all three loci, whereas three P. avenae isolates carried one or both of the SnTox1 and SnTox3 genes, indicating previously unrecognized potential for discovering additional effectors in the P. nodorum-wheat pathosystem. We utilized the pan-genomic comparative analysis to improve the prediction of pathogenicity effector candidates, recovering the three confirmed effectors among our top-ranked candidates. We propose applying this pan-genomic approach to identify the effector repertoire involved in other host-microbe interactions involving necrotrophic pathogens in the Pezizomycotina.
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Affiliation(s)
- Robert A Syme
- Centre for Crop & Disease Management, School of Molecular & Life Sciences, Curtin University, Bentley, Western Australia, Australia
| | - Kar-Chun Tan
- Centre for Crop & Disease Management, School of Molecular & Life Sciences, Curtin University, Bentley, Western Australia, Australia
| | - Kasia Rybak
- Centre for Crop & Disease Management, School of Molecular & Life Sciences, Curtin University, Bentley, Western Australia, Australia
| | - Timothy L Friesen
- Cereal Crops Research Unit, USDA-ARS Red River Valley Agricultural Research Center, Fargo, North Dakota
| | - Bruce A McDonald
- Plant Pathology Group, Institute of Integrative Biology, Swiss Federal Institute of Technology (ETH), Zurich, Switzerland
| | - Richard P Oliver
- Centre for Crop & Disease Management, School of Molecular & Life Sciences, Curtin University, Bentley, Western Australia, Australia
| | - James K Hane
- Centre for Crop & Disease Management, School of Molecular & Life Sciences, Curtin University, Bentley, Western Australia, Australia
- Curtin Institute for Computation, Curtin University, Bentley, Western Australia, Australia
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Global analysis of mutations driving microevolution of a heterozygous diploid fungal pathogen. Proc Natl Acad Sci U S A 2018; 115:E8688-E8697. [PMID: 30150418 PMCID: PMC6140516 DOI: 10.1073/pnas.1806002115] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Candida albicans is a heterozygous diploid yeast that is a commensal of the human gastrointestinal tract and a prevalent opportunistic pathogen. Here, whole-genome sequencing was performed on multiple C. albicans isolates passaged both in vitro and in vivo to characterize the complete spectrum of mutations arising in laboratory culture and in the mammalian host. We establish that, independent of culture niche, microevolution is primarily driven by de novo base substitutions and frequent short-tract loss-of-heterozygosity events. An average base-substitution rate of ∼1.2 × 10-10 per base pair per generation was observed in vitro, with higher rates inferred during host infection. Large-scale chromosomal changes were relatively rare, although chromosome 7 trisomies frequently emerged during passaging in a gastrointestinal model and was associated with increased fitness for this niche. Multiple chromosomal features impacted mutational patterns, with mutation rates elevated in repetitive regions, subtelomeric regions, and in gene families encoding cell surface proteins involved in host adhesion. Strikingly, de novo mutation rates were more than 800-fold higher in regions immediately adjacent to emergent loss-of-heterozygosity tracts, indicative of recombination-induced mutagenesis. Furthermore, genomes showed biased patterns of mutations suggestive of extensive purifying selection during passaging. These results reveal how both cell-intrinsic and cell-extrinsic factors influence C. albicans microevolution, and provide a quantitative picture of genome dynamics in this heterozygous diploid species.
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Horns F, Petit E, Hood ME. Massive Expansion of Gypsy-Like Retrotransposons in Microbotryum Fungi. Genome Biol Evol 2018; 9:363-371. [PMID: 28164239 PMCID: PMC5381629 DOI: 10.1093/gbe/evx011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/30/2017] [Indexed: 12/11/2022] Open
Abstract
Transposable elements (TEs) are selfish, autonomously replicating DNA sequences that constitute a major component of eukaryotic genomes and contribute to genome evolution through their movement and amplification. Many fungal genomes, including the anther-smut fungi in the basidiomycete genus Microbotryum, have genome defense mechanisms, such as repeat-induced point mutation (RIP), which hypermutate repetitive DNA and limit TE activity. Little is known about how hypermutation affects the tempo of TE activity and their sequence evolution. Here we report the identification of a massive burst-like expansion of Gypsy-like retrotransposons in a strain of Microbotryum. This TE expansion evidently occurred in the face of RIP-like hypermutation activity. By examining the fitness of individual TE insertion variants, we found that RIP-like mutations impair TE fitness and limit proliferation. Our results provide evidence for a punctuated pattern of TE expansion in a fungal genome, similar to that observed in animals and plants. While targeted hypermutation is often thought of as an effective protection against mobile element activity, our findings suggest that active TEs can persist and undergo selection while they proliferate in genomes that have RIP-like defenses.
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Affiliation(s)
- Felix Horns
- Department of Biology, Amherst College, Amherst, MA
| | - Elsa Petit
- Department of Biology, Amherst College, Amherst, MA
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Bulla I, Aliaga B, Lacal V, Bulla J, Grunau C, Chaparro C. Notos - a galaxy tool to analyze CpN observed expected ratios for inferring DNA methylation types. BMC Bioinformatics 2018; 19:105. [PMID: 29587630 PMCID: PMC5870242 DOI: 10.1186/s12859-018-2115-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Accepted: 03/13/2018] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND DNA methylation patterns store epigenetic information in the vast majority of eukaryotic species. The relatively high costs and technical challenges associated with the detection of DNA methylation however have created a bias in the number of methylation studies towards model organisms. Consequently, it remains challenging to infer kingdom-wide general rules about the functions and evolutionary conservation of DNA methylation. Methylated cytosine is often found in specific CpN dinucleotides, and the frequency distributions of, for instance, CpG observed/expected (CpG o/e) ratios have been used to infer DNA methylation types based on higher mutability of methylated CpG. RESULTS Predominantly model-based approaches essentially founded on mixtures of Gaussian distributions are currently used to investigate questions related to the number and position of modes of CpG o/e ratios. These approaches require the selection of an appropriate criterion for determining the best model and will fail if empirical distributions are complex or even merely moderately skewed. We use a kernel density estimation (KDE) based technique for robust and precise characterization of complex CpN o/e distributions without a priori assumptions about the underlying distributions. CONCLUSIONS We show that KDE delivers robust descriptions of CpN o/e distributions. For straightforward processing, we have developed a Galaxy tool, called Notos and available at the ToolShed, that calculates these ratios of input FASTA files and fits a density to their empirical distribution. Based on the estimated density the number and shape of modes of the distribution is determined, providing a rational for the prediction of the number and the types of different methylation classes. Notos is written in R and Perl.
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Affiliation(s)
- Ingo Bulla
- Institut für Mathematik und Informatik, Universität Greifswald, Walther-Rathenau-Str. 47, Greifswald, 17487 Germany
- Theoretical Biology and Biophysics, Group T-6, Los Alamos National Laboratory, New Mexico, Los Alamos USA
| | - Benoît Aliaga
- Univ. Perpignan Via Domitia, IHPE UMR 5244, CNRS, IFREMER, Univ. Montpellier, 58 Avenue Paul Alduy, Perpignan, 66860 France
| | - Virginia Lacal
- Department of Mathematics, University of Bergen, P.O. Box 7803, Bergen, 5020 Norway
| | - Jan Bulla
- Department of Mathematics, University of Bergen, P.O. Box 7803, Bergen, 5020 Norway
| | - Christoph Grunau
- Univ. Perpignan Via Domitia, IHPE UMR 5244, CNRS, IFREMER, Univ. Montpellier, 58 Avenue Paul Alduy, Perpignan, 66860 France
| | - Cristian Chaparro
- Univ. Perpignan Via Domitia, IHPE UMR 5244, CNRS, IFREMER, Univ. Montpellier, 58 Avenue Paul Alduy, Perpignan, 66860 France
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Abstract
Transposable elements have colonized the genomes of nearly all organisms, including fungi. Although transposable elements may sometimes provide beneficial functions to their hosts their overall impact is considered deleterious. As a result, the activity of transposable elements needs to be counterbalanced by the host genome defenses. In fungi, the primary genome defense mechanisms include repeat-induced point mutation (RIP) and methylation induced premeiotically, meiotic silencing by unpaired DNA, sex-induced silencing, cosuppression (also known as somatic quelling), and cotranscriptional RNA surveillance. Recent studies of the filamentous fungus Neurospora crassa have shown that the process of repeat recognition for RIP apparently involves interactions between coaligned double-stranded segments of chromosomal DNA. These studies have also shown that RIP can be mediated by the conserved pathway that establishes transcriptional (heterochromatic) silencing of repetitive DNA. In light of these new findings, RIP emerges as a specialized case of the general phenomenon of heterochromatic silencing of repetitive DNA.
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Analysis of Transposable Elements in Coccidioides Species. J Fungi (Basel) 2018; 4:jof4010013. [PMID: 29371508 PMCID: PMC5872316 DOI: 10.3390/jof4010013] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/05/2018] [Accepted: 01/11/2018] [Indexed: 12/24/2022] Open
Abstract
Coccidioides immitis and C. posadasii are primary pathogenic fungi that cause disease in immunologically-normal animals and people. The organism is found exclusively in arid regions of the Southwestern United States, Mexico, and South America, but not in other parts of the world. This study is a detailed analysis of the transposable elements (TE) in Coccidioides spp. As is common in most fungi, Class I and Class II transposons were identified and the LTR Gypsy superfamily is the most common. The minority of Coccidioides Gypsy transposons contained regions highly homologous to polyprotein domains. Phylogenetic analysis of the integrase and reverse transcriptase sequences revealed that many, but not all, of the Gypsy reverse transcriptase and integrase domains clustered by species suggesting extensive transposition after speciation of the two Coccidiodies spp. The TEs were clustered and the distribution is enriched for the ends on contigs. Analysis of gene expression data from C. immitis found that protein-coding genes within 1 kB of hAT or Gypsy TEs were poorly expressed. The expression of C. posadasii genes within 1 kB of Gypsy TEs was also significantly lower compared to all genes but the difference in expression was smaller than C. immitis. C. posadasii orthologs of C. immitis Gyspsy-associated genes were also likely to be TE-associated. In both C. immitis and C. posadasii the TEs were preferentially associated with genes annotated with protein kinase gene ontology terms. These observations suggest that TE may play a role in influencing gene expression in Coccidioides spp. Our hope is that these bioinformatic studies of the potential TE influence on expression and evolution of Coccidioides will prompt the development of testable hypotheses to better understand the role of TEs in the biology and gene regulation of Coccidioides spp.
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Li WC, Chen CL, Wang TF. Repeat-induced point (RIP) mutation in the industrial workhorse fungus Trichoderma reesei. Appl Microbiol Biotechnol 2018; 102:1567-1574. [DOI: 10.1007/s00253-017-8731-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Revised: 12/18/2017] [Accepted: 12/20/2017] [Indexed: 02/01/2023]
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Dallery JF, Lapalu N, Zampounis A, Pigné S, Luyten I, Amselem J, Wittenberg AHJ, Zhou S, de Queiroz MV, Robin GP, Auger A, Hainaut M, Henrissat B, Kim KT, Lee YH, Lespinet O, Schwartz DC, Thon MR, O'Connell RJ. Gapless genome assembly of Colletotrichum higginsianum reveals chromosome structure and association of transposable elements with secondary metabolite gene clusters. BMC Genomics 2017; 18:667. [PMID: 28851275 PMCID: PMC5576322 DOI: 10.1186/s12864-017-4083-x] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 08/21/2017] [Indexed: 11/11/2022] Open
Abstract
Background The ascomycete fungus Colletotrichum higginsianum causes anthracnose disease of brassica crops and the model plant Arabidopsis thaliana. Previous versions of the genome sequence were highly fragmented, causing errors in the prediction of protein-coding genes and preventing the analysis of repetitive sequences and genome architecture. Results Here, we re-sequenced the genome using single-molecule real-time (SMRT) sequencing technology and, in combination with optical map data, this provided a gapless assembly of all twelve chromosomes except for the ribosomal DNA repeat cluster on chromosome 7. The more accurate gene annotation made possible by this new assembly revealed a large repertoire of secondary metabolism (SM) key genes (89) and putative biosynthetic pathways (77 SM gene clusters). The two mini-chromosomes differed from the ten core chromosomes in being repeat- and AT-rich and gene-poor but were significantly enriched with genes encoding putative secreted effector proteins. Transposable elements (TEs) were found to occupy 7% of the genome by length. Certain TE families showed a statistically significant association with effector genes and SM cluster genes and were transcriptionally active at particular stages of fungal development. All 24 subtelomeres were found to contain one of three highly-conserved repeat elements which, by providing sites for homologous recombination, were probably instrumental in four segmental duplications. Conclusion The gapless genome of C. higginsianum provides access to repeat-rich regions that were previously poorly assembled, notably the mini-chromosomes and subtelomeres, and allowed prediction of the complete SM gene repertoire. It also provides insights into the potential role of TEs in gene and genome evolution and host adaptation in this asexual pathogen. Electronic supplementary material The online version of this article (10.1186/s12864-017-4083-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jean-Félix Dallery
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, Thiverval-Grignon, France
| | - Nicolas Lapalu
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, Thiverval-Grignon, France
| | - Antonios Zampounis
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, Thiverval-Grignon, France.,Present Address: Department of Deciduous Fruit Trees, Institute of Plant Breeding and Plant Genetic Resources, Hellenic Agricultural Organization 'Demeter', Naoussa, Greece
| | - Sandrine Pigné
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, Thiverval-Grignon, France
| | | | | | | | - Shiguo Zhou
- Laboratory for Molecular and Computational Genomics, Department of Chemistry, Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Marisa V de Queiroz
- Laboratório de Genética Molecular de Fungos, Universidade Federal de Viçosa, Viçosa, Brazil
| | - Guillaume P Robin
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, Thiverval-Grignon, France
| | - Annie Auger
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, Thiverval-Grignon, France
| | - Matthieu Hainaut
- CNRS UMR 7257, Aix-Marseille University, Marseille, France.,INRA, USC 1408 AFMB, Marseille, France
| | - Bernard Henrissat
- CNRS UMR 7257, Aix-Marseille University, Marseille, France.,INRA, USC 1408 AFMB, Marseille, France.,Department of Biological Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Ki-Tae Kim
- Department of Agricultural Biotechnology, Center for Fungal Genetic Resources, Seoul National University, Seoul, Korea
| | - Yong-Hwan Lee
- Department of Agricultural Biotechnology, Center for Fungal Genetic Resources, Seoul National University, Seoul, Korea
| | - Olivier Lespinet
- Laboratoire de Recherche en Informatique, CNRS, Université Paris-Sud, Orsay, France.,Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Orsay, France
| | - David C Schwartz
- Laboratory for Molecular and Computational Genomics, Department of Chemistry, Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Michael R Thon
- Instituto Hispano-Luso de Investigaciones Agrarias (CIALE), Department of Microbiology and Genetics, University of Salamanca, Salamanca, Spain
| | - Richard J O'Connell
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, Thiverval-Grignon, France.
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Abstract
The nuclear ribosomal DNA (rDNA) is considered as a paradigm of concerted evolution. Components of the rDNA tandem repeats (45S) are widely used in phylogenetic studies of different organisms and the internal transcribed spacer (ITS) region was recently selected as a fungal DNA bar code. However, rRNA pseudogenes, as one kind of escape from concerted evolution, were reported in a wide range of organisms, especially in plants and animals. Moreover, large numbers of 5S rRNA pseudogenes were identified in several filamentous ascomycetes. To study whether rDNA evolves in a strict concerted manner and test whether rRNA pseudogenes exist in more species of ascomycetes, intragenomic rDNA polymorphisms were analyzed using whole genome sequences. Divergent rDNA paralogs were found to coexist within a single genome in seven filamentous ascomycetes examined. A great number of paralogs were identified as pseudogenes according to the mutation and secondary structure analyses. Phylogenetic analyses of the three rRNA coding regions of the 45S rDNA repeats, i.e., 18S, 5.8S, and 28S, revealed an interspecies clustering pattern of those different rDNA paralogs. The identified rRNA pseudogenic sequences were validated using specific primers designed. Mutation analyses revealed that the repeat-induced point (RIP) mutation was probably responsible for the formation of those rRNA pseudogenes.
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40
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Donnart T, Piednoël M, Higuet D, Bonnivard É. Filamentous ascomycete genomes provide insights into Copia retrotransposon diversity in fungi. BMC Genomics 2017; 18:410. [PMID: 28545447 PMCID: PMC5445492 DOI: 10.1186/s12864-017-3795-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 05/16/2017] [Indexed: 12/31/2022] Open
Abstract
Background The relative scarcity of Copia retrotransposons has been recently characterized in metazoans in comparison with the other superfamilies of LTR elements. Furthermore, Copia retrotransposons have often a particular dynamics that results in a highly predominant single clade of elements within a large host taxon, such as the GalEa-like retrotransposons in crustaceans. Taking advantage of the skyrocketing amount of genomic data available for fungi, we carried out the first large-scale comparative genomic analysis of the Copia clades in filamentous ascomycetes. Results Screening 30 completely sequenced genomes allowed us to identify more than 2500 Copia copies with conserved LTR, which are distributed in 138 families. Their characterization revealed that fungal Copia diversity is much broader than previously thought with at least 27 clades, 23 of which likely correspond to new ones. While the Copia copy number is low in most species, the two clades GalEa and FunCo1 are widely distributed and highly dominate Copia content as they both account for 80% of the detected sequences. Conclusions In Fungi, GalEa retrotransposons are restricted to Pezizomycotina in which they can make up an outstandingly high proportion of the genome (up to 10% in Cenococcum geophilum). At last, we revealed that fungal GalEa elements structurally differ from all other Copia elements with an absence of Primer Binding Site. These elements however harbor a Conserved Hairpin Site which is probably essential for their transposition. Electronic supplementary material The online version of this article (doi:10.1186/s12864-017-3795-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Tifenn Donnart
- Sorbonne Universités, UPMC Univ Paris 06, Univ Antilles, Univ Nice Sophia Antipolis, CNRS, Evolution Paris Seine - Institut de Biologie Paris Seine (EPS - IBPS), 75005, Paris, France
| | - Mathieu Piednoël
- Department of Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, Carl-von-Linné Weg 10, D-50829, Cologne, Germany
| | - Dominique Higuet
- Sorbonne Universités, UPMC Univ Paris 06, Univ Antilles, Univ Nice Sophia Antipolis, CNRS, Evolution Paris Seine - Institut de Biologie Paris Seine (EPS - IBPS), 75005, Paris, France
| | - Éric Bonnivard
- Sorbonne Universités, UPMC Univ Paris 06, Univ Antilles, Univ Nice Sophia Antipolis, CNRS, Evolution Paris Seine - Institut de Biologie Paris Seine (EPS - IBPS), 75005, Paris, France.
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41
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DNA sequence homology induces cytosine-to-thymine mutation by a heterochromatin-related pathway in Neurospora. Nat Genet 2017; 49:887-894. [PMID: 28459455 PMCID: PMC5474309 DOI: 10.1038/ng.3857] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Accepted: 03/31/2017] [Indexed: 12/16/2022]
Abstract
Eukaryotic genomes contain substantial amounts of repetitive DNA organized in the form of constitutive heterochromatin and associated with repressive epigenetic modifications, such as H3K9me3 and C5-cytosine methylation (5mC). In the fungus Neurospora crassa, H3K9me3 and 5mC are catalyzed, respectively, by a conserved SUV39 histone methyltransferase DIM-5 and a DNMT1-like cytosine methyltransferase DIM-2. Here we show that DIM-2 can also mediate Repeat-Induced Point mutation (RIP) of repetitive DNA in N. crassa. We further show that DIM-2-dependent RIP requires DIM-5, HP1, and other known heterochromatin factors, implying the role of a repeat-induced heterochromatin-related process. Our previous findings suggest that the mechanism of repeat recognition for RIP involves direct interactions between homologous double-stranded (ds) DNA segments. We thus now propose that, in somatic cells, homologous dsDNA/dsDNA interactions between a small number of repeat copies can nucleate a transient heterochromatic state, which, on longer repeat arrays, may lead to the formation of constitutive heterochromatin.
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42
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Clutterbuck AJ. Genomic CG dinucleotide deficiencies associated with transposable element hypermutation in Basidiomycetes, some lower fungi, a moss and a clubmoss. Fungal Genet Biol 2017; 104:16-28. [PMID: 28438577 DOI: 10.1016/j.fgb.2017.04.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 04/10/2017] [Accepted: 04/17/2017] [Indexed: 12/15/2022]
Abstract
Many Basidiomycete genomes include substantial fractions that are deficient in CG dinucleotides, in extreme cases amounting to 70% of the genome. CG deficiency is variable and correlates with genome size and, more closely, with transposable element (TE) content. Many species have limited CG deficiency; it is therefore likely that there are other mechanisms that can control TE proliferation. Examination of TEs confirms that C-to-T transition mutations in CG dinucleotides may comprise a conspicuous proportion of differences between paired elements, however transition/transversion ratios are never as high as those due to RIP in some Ascomycetes, suggesting that repeat-associated CG mutation is not totally pervasive. This has allowed gene family expansion in Basidiomycetes, although CG transition differences are often prominent in paired gene family members, and are evidently responsible for destruction of some copies. A few lower fungal genomes exhibit similar evidence of repeat-associated CG mutation, as do the genomes of the two lower plants Physcomitrella patens and Selaginella moellendorffii, in both of which mutation parallels published methylation of CHG as well as CG nucleotides. In Basidiomycete DNA methylation has been reported to be largely confined to CG dinucleotides in repetitive DNA, but while methylation and mutation are evidently associated, it is not clear which is cause and which effect.
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Affiliation(s)
- A John Clutterbuck
- Wolfson Link Building, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, UK.
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43
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Wang Y, Wang T, Qiao L, Zhu J, Fan J, Zhang T, Wang ZX, Li W, Chen A, Huang B. DNA methyltransferases contribute to the fungal development, stress tolerance and virulence of the entomopathogenic fungus Metarhizium robertsii. Appl Microbiol Biotechnol 2017; 101:4215-4226. [PMID: 28238081 DOI: 10.1007/s00253-017-8197-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 02/04/2017] [Accepted: 02/11/2017] [Indexed: 12/31/2022]
Abstract
DNA methylation is an important epigenetic mark in mammals, plants, and fungi and depends on multiple genetic pathways involving de novo and maintenance DNA methyltransferases (DNMTases). Metarhizium robertsii, a model system for investigating insect-fungus interactions, has been used as an environmentally friendly alternative to chemical insecticides. However, little is known concerning the molecular basis for DNA methylation. Here, we report on the roles of two DNMTases (MrRID and MrDIM-2) by characterizing ΔMrRID, ΔMrDIM-2, and ΔRID/ΔDIM-2 mutants. The results showed that approximately 71, 10, and 8% of mC sites remained in the ΔMrRID, ΔMrDIM-2, and ΔRID/ΔDIM-2 strains, respectively, compared with the wild-type (WT) strain. Further analysis showed that MrRID regulates the specificity of DNA methylation and MrDIM-2 is responsible for most DNA methylation, implying an interaction or cooperation between MrRID and MrDIM-2 for DNA methylation. Moreover, the ΔMrDIM-2 and ΔRID/ΔDIM-2 strains showed more defects in radial growth and conidial production compared to the WT. Under ultraviolet (UV) irradiation or heat stress, an obvious reduction in spore viability was observed for all the mutant strains compared to the WT. The spore median lethal times (LT50s) for the ΔMrDIM-2 and ΔRID/ΔDIM-2 strains in the greater wax moth, Galleria mellonella, were decreased by 47.7 and 65.9%, respectively, which showed that MrDIM-2 is required for full fungal virulence. Our data advances the understanding of the function of DNMTase in entomopathogenic fungi, which should contribute to future epigenetic investigations in fungi.
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Affiliation(s)
- Yulong Wang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, 230036, China
| | - Tiantian Wang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, 230036, China
| | - Lintao Qiao
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, 230036, China
| | - Jianyu Zhu
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, 230036, China
| | - Jinrui Fan
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, 230036, China
| | - Tingting Zhang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, 230036, China
| | - Zhang-Xun Wang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, 230036, China.,School of Plant Protection, Anhui Agricultural University, Hefei, 230036, China
| | - Wanzhen Li
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, 230036, China.,Engineering Technology Research Center of Microbial Fermentation Anhui Province, Anhui Polytechnic University, Wuhu, 241000, China
| | - Anhui Chen
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, 230036, China.,Department of Food and Biology, Xuzhou Institute of Technology, Xuzhou, 221008, China
| | - Bo Huang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, 230036, China.
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44
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Identification of A. arborescens, A. grandis, and A. protenta as new members of the European Alternaria population on potato. Fungal Biol 2017; 121:172-188. [DOI: 10.1016/j.funbio.2016.11.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 11/21/2016] [Accepted: 11/28/2016] [Indexed: 11/24/2022]
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45
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Braga RM, Santana MF, Costa RVD, Brommonschenkel SH, de Araújo EF, de Queiroz MV. Transposable elements belonging to the Tc1-Mariner superfamily are heavily mutated in Colletotrichum graminicola. Mycologia 2017; 106:629-41. [DOI: 10.3852/13-262] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Raíssa Mesquita Braga
- Departamento de Microbiologia, Instituto de Ciências Biomédicas II, Universidade de São Paulo, Avenida Professor Lineu Prestes 1374, Cidade Universitária, São Paulo, Brasil. CEP: 05508-900
| | - Mateus Ferreira Santana
- Departamento de Microbiologia, Universidade Federal de Viçosa, Avenida Peter Henry Rolfs s/n, Campus Universitário, Viçosa, Brasil. CEP: 36570-000
| | - Rodrigo Veras da Costa
- Embrapa Milho e Sorgo, Rod MG 424 Km 65, Sete Lagoas, Minas Gerais, Brasil. CEP: 35701-970
| | - Sergio Herminio Brommonschenkel
- Departamento de Fitopatologia, Universidade Federal de Viçosa, Avenida Peter Henry Rolfs s/n, Campus Universitário, Viçosa, Brasil. CEP: 36570-000
| | - Elza Fernandes de Araújo
- Fundação de Amparo à Pesquisa do Estado de Minas Gerais, Rua Raul Pompeia 101, São Pedro, Belo Horizonte, Brasil. CEP: 30330-080
| | - Marisa Vieira de Queiroz
- Departamento de Microbiologia, Universidade Federal de Viçosa, Avenida Peter Henry Rolfs s/n, Campus Universitário, Viçosa, Brasil. CEP: 36570-000
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46
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Li WC, Huang CH, Chen CL, Chuang YC, Tung SY, Wang TF. Trichoderma reesei complete genome sequence, repeat-induced point mutation, and partitioning of CAZyme gene clusters. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:170. [PMID: 28690679 PMCID: PMC5496416 DOI: 10.1186/s13068-017-0825-x] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 05/22/2017] [Indexed: 05/13/2023]
Abstract
BACKGROUND Trichoderma reesei (Ascomycota, Pezizomycotina) QM6a is a model fungus for a broad spectrum of physiological phenomena, including plant cell wall degradation, industrial production of enzymes, light responses, conidiation, sexual development, polyketide biosynthesis, and plant-fungal interactions. The genomes of QM6a and its high enzyme-producing mutants have been sequenced by second-generation-sequencing methods and are publicly available from the Joint Genome Institute. While these genome sequences have offered useful information for genomic and transcriptomic studies, their limitations and especially their short read lengths make them poorly suited for some particular biological problems, including assembly, genome-wide determination of chromosome architecture, and genetic modification or engineering. RESULTS We integrated Pacific Biosciences and Illumina sequencing platforms for the highest-quality genome assembly yet achieved, revealing seven telomere-to-telomere chromosomes (34,922,528 bp; 10877 genes) with 1630 newly predicted genes and >1.5 Mb of new sequences. Most new sequences are located on AT-rich blocks, including 7 centromeres, 14 subtelomeres, and 2329 interspersed AT-rich blocks. The seven QM6a centromeres separately consist of 24 conserved repeats and 37 putative centromere-encoded genes. These findings open up a new perspective for future centromere and chromosome architecture studies. Next, we demonstrate that sexual crossing readily induced cytosine-to-thymine point mutations on both tandem and unlinked duplicated sequences. We also show by bioinformatic analysis that T. reesei has evolved a robust repeat-induced point mutation (RIP) system to accumulate AT-rich sequences, with longer AT-rich blocks having more RIP mutations. The widespread distribution of AT-rich blocks correlates genome-wide partitions with gene clusters, explaining why clustering of genes has been reported to not influence gene expression in T. reesei. CONCLUSION Compartmentation of ancestral gene clusters by AT-rich blocks might promote flexibilities that are evolutionarily advantageous in this fungus' soil habitats and other natural environments. Our analyses, together with the complete genome sequence, provide a better blueprint for biotechnological and industrial applications.
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Affiliation(s)
- Wan-Chen Li
- Taiwan International Graduate Program in Molecular and Cellular Biology, Academia Sinica, Taipei, 115 Taiwan
- Institute of Life Sciences, National Defense Medical Center, Taipei, 115 Taiwan
- Institute of Molecular Biology, Academia Sinica, Taipei, 115 Taiwan
| | - Chien-Hao Huang
- Institute of Molecular Biology, Academia Sinica, Taipei, 115 Taiwan
- Institute of Genome Sciences, National Yang-Ming University, Taipei, 112 Taiwan
| | - Chia-Ling Chen
- Institute of Molecular Biology, Academia Sinica, Taipei, 115 Taiwan
| | - Yu-Chien Chuang
- Institute of Molecular Biology, Academia Sinica, Taipei, 115 Taiwan
| | - Shu-Yun Tung
- Institute of Molecular Biology, Academia Sinica, Taipei, 115 Taiwan
| | - Ting-Fang Wang
- Taiwan International Graduate Program in Molecular and Cellular Biology, Academia Sinica, Taipei, 115 Taiwan
- Institute of Molecular Biology, Academia Sinica, Taipei, 115 Taiwan
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47
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Gladyshev E, Kleckner N. Recombination-independent recognition of DNA homology for repeat-induced point mutation. Curr Genet 2016; 63:389-400. [PMID: 27628707 DOI: 10.1007/s00294-016-0649-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 09/04/2016] [Accepted: 09/06/2016] [Indexed: 12/31/2022]
Abstract
Numerous cytogenetic observations have shown that homologous chromosomes (or individual chromosomal loci) can engage in specific pairing interactions in the apparent absence of DNA breakage and recombination, suggesting that canonical recombination-mediated mechanisms may not be the only option for sensing DNA/DNA homology. One proposed mechanism for such recombination-independent homology recognition involves direct contacts between intact double-stranded DNA molecules. The strongest in vivo evidence for the existence of such a mechanism is provided by the phenomena of homology-directed DNA modifications in fungi, known as repeat-induced point mutation (RIP, discovered in Neurospora crassa) and methylation-induced premeiotically (MIP, discovered in Ascobolus immersus). In principle, Neurospora RIP can detect the presence of gene-sized DNA duplications irrespectively of their origin, underlying nucleotide sequence, coding capacity or relative, as well as absolute positions in the genome. Once detected, both sequence copies are altered by numerous cytosine-to-thymine (C-to-T) mutations that extend specifically over the duplicated region. We have recently shown that Neurospora RIP does not require MEI-3, the only RecA/Rad51 protein in this organism, consistent with a recombination-independent mechanism. Using an ultra-sensitive assay for RIP mutation, we have defined additional features of this process. We have shown that RIP can detect short islands of homology of only three base-pairs as long as many such islands are arrayed with a periodicity of 11 or 12 base-pairs along a pair of DNA molecules. While the presence of perfect homology is advantageous, it is not required: chromosomal segments with overall sequence identity of only 35-36 % can still be recognized by RIP. Importantly, in order for this process to work efficiently, participating DNA molecules must be able to co-align along their lengths. Based on these findings, we have proposed a model, in which sequence homology is detected by direct interactions between slightly-extended double-stranded DNAs. As a next step, it will be important to determine if the uncovered principles also apply to other processes that involve recombination-independent interactions between homologous chromosomal loci in vivo as well as to protein-free DNA/DNA interactions that were recently observed under biologically relevant conditions in vitro.
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Affiliation(s)
- Eugene Gladyshev
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Room NW140, Cambridge, MA, 02138, USA.
| | - Nancy Kleckner
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Room NW140, Cambridge, MA, 02138, USA.
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48
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Vanheule A, Audenaert K, Warris S, van de Geest H, Schijlen E, Höfte M, De Saeger S, Haesaert G, Waalwijk C, van der Lee T. Living apart together: crosstalk between the core and supernumerary genomes in a fungal plant pathogen. BMC Genomics 2016; 17:670. [PMID: 27552804 PMCID: PMC4994206 DOI: 10.1186/s12864-016-2941-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Accepted: 07/14/2016] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Eukaryotes display remarkable genome plasticity, which can include supernumerary chromosomes that differ markedly from the core chromosomes. Despite the widespread occurrence of supernumerary chromosomes in fungi, their origin, relation to the core genome and the reason for their divergent characteristics are still largely unknown. The complexity of genome assembly due to the presence of repetitive DNA partially accounts for this. RESULTS Here we use single-molecule real-time (SMRT) sequencing to assemble the genome of a prominent fungal wheat pathogen, Fusarium poae, including at least one supernumerary chromosome. The core genome contains limited transposable elements (TEs) and no gene duplications, while the supernumerary genome holds up to 25 % TEs and multiple gene duplications. The core genome shows all hallmarks of repeat-induced point mutation (RIP), a defense mechanism against TEs, specific for fungi. The absence of RIP on the supernumerary genome accounts for the differences between the two (sub)genomes, and results in a functional crosstalk between them. The supernumerary genome is a reservoir for TEs that migrate to the core genome, and even large blocks of supernumerary sequence (>200 kb) have recently translocated to the core. Vice versa, the supernumerary genome acts as a refuge for genes that are duplicated from the core genome. CONCLUSIONS For the first time, a mechanism was determined that explains the differences that exist between the core and supernumerary genome in fungi. Different biology rather than origin was shown to be responsible. A "living apart together" crosstalk exists between the core and supernumerary genome, accelerating chromosomal and organismal evolution.
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Affiliation(s)
- Adriaan Vanheule
- Department of Applied Biosciences, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
- Wageningen UR, Wageningen, The Netherlands
| | - Kris Audenaert
- Department of Applied Biosciences, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | | | | | | | - Monica Höfte
- Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Sarah De Saeger
- Department of Bioanalysis, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium
| | - Geert Haesaert
- Department of Applied Biosciences, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
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Chang TC, Salvucci A, Crous PW, Stergiopoulos I. Comparative Genomics of the Sigatoka Disease Complex on Banana Suggests a Link between Parallel Evolutionary Changes in Pseudocercospora fijiensis and Pseudocercospora eumusae and Increased Virulence on the Banana Host. PLoS Genet 2016; 12:e1005904. [PMID: 27513322 PMCID: PMC4981473 DOI: 10.1371/journal.pgen.1005904] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 02/05/2016] [Indexed: 01/05/2023] Open
Abstract
The Sigatoka disease complex, caused by the closely-related Dothideomycete fungi Pseudocercospora musae (yellow sigatoka), Pseudocercospora eumusae (eumusae leaf spot), and Pseudocercospora fijiensis (black sigatoka), is currently the most devastating disease on banana worldwide. The three species emerged on bananas from a recent common ancestor and show clear differences in virulence, with P. eumusae and P. fijiensis considered the most aggressive. In order to understand the genomic modifications associated with shifts in the species virulence spectra after speciation, and to identify their pathogenic core that can be exploited in disease management programs, we have sequenced and analyzed the genomes of P. eumusae and P. musae and compared them with the available genome sequence of P. fijiensis. Comparative analysis of genome architectures revealed significant differences in genome size, mainly due to different rates of LTR retrotransposon proliferation. Still, gene counts remained relatively equal and in the range of other Dothideomycetes. Phylogenetic reconstruction based on a set of 46 conserved single-copy genes strongly supported an earlier evolutionary radiation of P. fijiensis from P. musae and P. eumusae. However, pairwise analyses of gene content indicated that the more virulent P. eumusae and P. fijiensis share complementary patterns of expansions and contractions in core gene families related to metabolism and enzymatic degradation of plant cell walls, suggesting that the evolution of virulence in these two pathogens has, to some extent, been facilitated by convergent changes in metabolic pathways associated with nutrient acquisition and assimilation. In spite of their common ancestry and shared host-specificity, the three species retain fairly dissimilar repertoires of effector proteins, suggesting that they likely evolved different strategies for manipulating the host immune system. Finally, 234 gene families, including seven putative effectors, were exclusively present in the three Sigatoka species, and could thus be related to adaptation to the banana host. Understanding the evolutionary and genomic changes involved in the emergence of new pathogens and shifts in virulence spectra is vital for deciphering the biological process of disease emergence and for designing new and effective disease control methods. In this study, we employed comparative genomics in order to examine the nature, diversity, and extent of genomic modifications associated with changes in virulence among Pseudocercospora musae, Pseudocercospora eumusae, and Pseudocercospora fijiensis, the main constituents of the Sigatoka disease complex on banana, currently one of the most destructive diseases on banana worldwide. Our comparative genome analyses have highlighted the role of pathoadaptive changes in virulence associated genes, such as those encoding for effectors, in shaping the underlying differences in virulence spectra among the three species, and also revealed that changes in the size of gene families associated with nutrient acquisition and assimilation are more respectful of the species virulence profiles rather than their evolutionary relationships. Thus, we posit that next to species-specific evolutionary adaptations in virulence-associated genes, the increase in virulence of P. eumusae and P. fijiensis has been driven by convergent evolution in metabolic pathways that likely facilitate a higher efficiency of nutrient acquisition, uptake, and utilization.
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Affiliation(s)
- Ti-Cheng Chang
- Department of Plant Pathology, University of California Davis, Davis, California, United States of America
| | - Anthony Salvucci
- Department of Plant Pathology, University of California Davis, Davis, California, United States of America
| | - Pedro W. Crous
- CBS-KNAW Fungal Biodiversity Centre, Utrecht, The Netherlands
| | - Ioannis Stergiopoulos
- Department of Plant Pathology, University of California Davis, Davis, California, United States of America
- * E-mail:
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50
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Testa AC, Oliver RP, Hane JK. OcculterCut: A Comprehensive Survey of AT-Rich Regions in Fungal Genomes. Genome Biol Evol 2016; 8:2044-64. [PMID: 27289099 PMCID: PMC4943192 DOI: 10.1093/gbe/evw121] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/14/2016] [Indexed: 12/03/2022] Open
Abstract
We present a novel method to measure the local GC-content bias in genomes and a survey of published fungal species. The method, enacted as "OcculterCut" (https://sourceforge.net/projects/occultercut, last accessed April 30, 2016), identified species containing distinct AT-rich regions. In most fungal taxa, AT-rich regions are a signature of repeat-induced point mutation (RIP), which targets repetitive DNA and decreases GC-content though the conversion of cytosine to thymine bases. RIP has in turn been identified as a driver of fungal genome evolution, as RIP mutations can also occur in single-copy genes neighboring repeat-rich regions. Over time RIP perpetuates "two speeds" of gene evolution in the GC-equilibrated and AT-rich regions of fungal genomes. In this study, genomes showing evidence of this process are found to be common, particularly among the Pezizomycotina. Further analysis highlighted differences in amino acid composition and putative functions of genes from these regions, supporting the hypothesis that these regions play an important role in fungal evolution. OcculterCut can also be used to identify genes undergoing RIP-assisted diversifying selection, such as small, secreted effector proteins that mediate host-microbe disease interactions.
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Affiliation(s)
- Alison C Testa
- Department of Environment & Agriculture, Centre for Crop and Disease Management, Curtin University, Perth, Australia
| | - Richard P Oliver
- Department of Environment & Agriculture, Centre for Crop and Disease Management, Curtin University, Perth, Australia
| | - James K Hane
- Department of Environment & Agriculture, Centre for Crop and Disease Management, Curtin University, Perth, Australia Curtin Institute for Computation, Curtin University, Perth, Australia
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