1
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Treindl AD, Stapley J, Croll D, Leuchtmann A. Two-speed genomes of Epichloe fungal pathogens show contrasting signatures of selection between species and across populations. Mol Ecol 2024; 33:e17242. [PMID: 38084851 DOI: 10.1111/mec.17242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 11/23/2023] [Accepted: 11/30/2023] [Indexed: 12/19/2023]
Abstract
Antagonistic selection between pathogens and their hosts can drive rapid evolutionary change and leave distinct molecular footprints of past and ongoing selection in the genomes of the interacting species. Despite an increasing availability of tools able to identify signatures of selection, the genetic mechanisms underlying coevolutionary interactions and the specific genes involved are still poorly understood, especially in heterogeneous natural environments. We searched the genomes of two species of Epichloe plant pathogen for evidence of recent selection. The Epichloe genus includes highly host-specific species that can sterilize their grass hosts. We performed selection scans using genome-wide SNP data from seven natural populations of two co-occurring Epichloe sibling species specialized on different hosts. We found evidence of recent (and ongoing) selective sweeps across the genome in both species. However, selective sweeps were more abundant in the species with a larger effective population size. Sweep regions often overlapped with highly polymorphic AT-rich regions supporting the role of these genome compartments in adaptive evolution. Although most loci under selection were specific to individual populations, we could also identify several candidate genes targeted by selection in sweep regions shared among populations. The genes encoded small secreted proteins typical of fungal effectors and cell wall-degrading enzymes. By investigating the genomic signatures of selection across multiple populations and species, this study contributes to our understanding of complex adaptive processes in natural plant pathogen systems.
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Affiliation(s)
- Artemis D Treindl
- Plant Ecological Genetics Group, Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
- Biodiversity and Conservation Biology, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Jessica Stapley
- Plant Pathology Group, Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Adrian Leuchtmann
- Plant Ecological Genetics Group, Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
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2
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Taliadoros D, Stukenbrock EH. The use of evolutionary analyses to predict functionally relevant traits in filamentous plant pathogens. Curr Opin Microbiol 2023; 73:102244. [PMID: 36889024 DOI: 10.1016/j.mib.2022.102244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 10/27/2022] [Accepted: 11/03/2022] [Indexed: 03/08/2023]
Abstract
Identifying traits involved in plant-pathogen interactions is one of the major objectives in molecular plant pathology. Evolutionary analyses may assist in the identification of genes encoding traits that are involved in virulence and local adaptation, including adaptation to agricultural intervention strategies. In the past decades, the number of available genome sequences of fungal plant pathogens has rapidly increased, providing a rich source for the discovery of functionally important genes as well as inference of species histories. Positive selection in the form of diversifying or directional selection leaves particular signatures in genome alignments and can be identified with statistical genetics methods. This review summarises the concepts and approaches used in evolutionary genomics and lists major discoveries related to plant-pathogen adaptative evolution. We underline the significant contribution of evolutionary genomics in discovering virulence-related traits and the study of plant-pathogen ecology and adaptive evolution.
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3
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Quintanilha-Peixoto G, Marone MP, Raya FT, José J, Oliveira A, Fonseca PLC, Tomé LMR, Bortolini DE, Kato RB, Araújo DS, De-Paula RB, Cuesta-Astroz Y, Duarte EAA, Badotti F, de Carvalho Azevedo VA, Brenig B, Soares ACF, Carazzolle MF, Pereira GAG, Aguiar ERGR, Góes-Neto A. Phylogenomics and gene selection in Aspergillus welwitschiae: Possible implications in the pathogenicity in Agave sisalana. Genomics 2022; 114:110517. [PMID: 36306958 DOI: 10.1016/j.ygeno.2022.110517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 10/10/2022] [Accepted: 10/25/2022] [Indexed: 11/04/2022]
Abstract
Aspergillus welwitschiae causes bole rot disease in sisal (Agave sisalana and related species) which affects the production of natural fibers in Brazil, the main worldwide producer of sisal fibers. This fungus is a saprotroph with a broad host range. Previous research established A. welwitschiae as the only causative agent of bole rot in the field, but little is known about the evolution of this species and its strains. In this work, we performed a comparative genomics analysis of 40 Aspergillus strains. We show the conflicting molecular identity of this species, with one sisal-infecting strain sharing its last common ancestor with Aspergillus niger, having diverged only 833 thousand years ago. Furthermore, our analysis of positive selection reveals sites under selection in genes coding for siderophore transporters, Sodium‑calcium exchangers, and Phosphatidylethanolamine-binding proteins (PEBPs). Herein, we discuss the possible impacts of these gene functions on the pathogenicity in sisal.
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Affiliation(s)
| | - Marina Püpke Marone
- Department of Genetics, Evolution, Microbiology, and Immunology, University of Campinas, Campinas, São Paulo, Brazil
| | - Fábio Trigo Raya
- Department of Genetics, Evolution, Microbiology, and Immunology, University of Campinas, Campinas, São Paulo, Brazil
| | - Juliana José
- Department of Genetics, Evolution, Microbiology, and Immunology, University of Campinas, Campinas, São Paulo, Brazil
| | - Adriele Oliveira
- Department of Genetics, Evolution, Microbiology, and Immunology, University of Campinas, Campinas, São Paulo, Brazil
| | | | | | - Dener Eduardo Bortolini
- Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Rodrigo Bentes Kato
- Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Daniel S Araújo
- Program in Bioinformatics, Loyola University Chicago, Chicago, United States
| | - Ruth B De-Paula
- Department of Neurology, Baylor College of Medicine, Houston, United States
| | - Yesid Cuesta-Astroz
- Instituto Colombiano de Medicina Tropical, Universidad CES, Medellín, Colombia
| | - Elizabeth A A Duarte
- Centro Universitário Maria Milza, Cruz das Almas, Brazil; Center of Agricultural, Environmental and Biological Sciences, Universidade Federal do Recôncavo da Bahia, Cruz das Almas, Brazil
| | - Fernanda Badotti
- Department of Chemistry, Federal Center of Technological Education of Minas Gerais, Belo Horizonte, Brazil
| | | | - Bertram Brenig
- Institute of Veterinary Medicine, University of Göttingen, Göttingen, Germany
| | - Ana Cristina Fermino Soares
- Center of Agricultural, Environmental and Biological Sciences, Universidade Federal do Recôncavo da Bahia, Cruz das Almas, Brazil
| | - Marcelo Falsarella Carazzolle
- Department of Genetics, Evolution, Microbiology, and Immunology, University of Campinas, Campinas, São Paulo, Brazil
| | | | - Eric Roberto Guimarães Rocha Aguiar
- Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil; Center of Biotechnology and Genetics, Department of Biological Science, Universidade Estadual de Santa Cruz, Ilhéus, Brazil
| | - Aristóteles Góes-Neto
- Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
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Abraham A, LaBella AL, Capra JA, Rokas A. Mosaic patterns of selection in genomic regions associated with diverse human traits. PLoS Genet 2022; 18:e1010494. [PMID: 36342969 PMCID: PMC9671423 DOI: 10.1371/journal.pgen.1010494] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 11/17/2022] [Accepted: 10/21/2022] [Indexed: 11/09/2022] Open
Abstract
Natural selection shapes the genetic architecture of many human traits. However, the prevalence of different modes of selection on genomic regions associated with variation in traits remains poorly understood. To address this, we developed an efficient computational framework to calculate positive and negative enrichment of different evolutionary measures among regions associated with complex traits. We applied the framework to summary statistics from >900 genome-wide association studies (GWASs) and 11 evolutionary measures of sequence constraint, population differentiation, and allele age while accounting for linkage disequilibrium, allele frequency, and other potential confounders. We demonstrate that this framework yields consistent results across GWASs with variable sample sizes, numbers of trait-associated SNPs, and analytical approaches. The resulting evolutionary atlas maps diverse signatures of selection on genomic regions associated with complex human traits on an unprecedented scale. We detected positive enrichment for sequence conservation among trait-associated regions for the majority of traits (>77% of 290 high power GWASs), which included reproductive traits. Many traits also exhibited substantial positive enrichment for population differentiation, especially among hair, skin, and pigmentation traits. In contrast, we detected widespread negative enrichment for signatures of balancing selection (51% of GWASs) and absence of enrichment for evolutionary signals in regions associated with late-onset Alzheimer's disease. These results support a pervasive role for negative selection on regions of the human genome that contribute to variation in complex traits, but also demonstrate that diverse modes of evolution are likely to have shaped trait-associated loci. This atlas of evolutionary signatures across the diversity of available GWASs will enable exploration of the relationship between the genetic architecture and evolutionary processes in the human genome.
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Affiliation(s)
- Abin Abraham
- Vanderbilt University Medical Center, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Abigail L. LaBella
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
- Evolutionary Studies Initiative, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Bioinformatics and Genomics, University of North Carolina at Charlotte, North Carolina, United States of America
- North Carolina Research Center, Kannapolis, North Carolina, United States of America
| | - John A. Capra
- Bakar Computational Health Sciences Institute, University of California, San Francisco, California, United States of America
- Department of Epidemiology and Biostatistics, University of California, San Francisco, California, United States of America
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
- Evolutionary Studies Initiative, Vanderbilt University, Nashville, Tennessee, United States of America
- Department of Biomedical Informatics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Vanderbilt Genetics Institute, Vanderbilt University, Nashville, Tennessee, United States of America
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5
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Sotiropoulos AG, Arango-Isaza E, Ban T, Barbieri C, Bourras S, Cowger C, Czembor PC, Ben-David R, Dinoor A, Ellwood SR, Graf J, Hatta K, Helguera M, Sánchez-Martín J, McDonald BA, Morgounov AI, Müller MC, Shamanin V, Shimizu KK, Yoshihira T, Zbinden H, Keller B, Wicker T. Global genomic analyses of wheat powdery mildew reveal association of pathogen spread with historical human migration and trade. Nat Commun 2022; 13:4315. [PMID: 35882860 PMCID: PMC9315327 DOI: 10.1038/s41467-022-31975-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 07/13/2022] [Indexed: 12/25/2022] Open
Abstract
The fungus Blumeria graminis f. sp. tritici causes wheat powdery mildew disease. Here, we study its spread and evolution by analyzing a global sample of 172 mildew genomes. Our analyses show that B.g. tritici emerged in the Fertile Crescent during wheat domestication. After it spread throughout Eurasia, colonization brought it to America, where it hybridized with unknown grass mildew species. Recent trade brought USA strains to Japan, and European strains to China. In both places, they hybridized with local ancestral strains. Thus, although mildew spreads by wind regionally, our results indicate that humans drove its global spread throughout history and that mildew rapidly evolved through hybridization. The fungus Blumeria graminis f. sp. tritici causes wheat powdery mildew disease. Here, Sotiropoulos et al. analyze a global sample of 172 mildew genomes, providing evidence that humans drove global spread of the pathogen throughout history and that mildew rapidly evolved through hybridization with local fungal strains.
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Affiliation(s)
| | - Epifanía Arango-Isaza
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Tomohiro Ban
- Kihara Institute for Biological Research, Yokohama City University, Yokohama, Kanagawa, Japan
| | - Chiara Barbieri
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.,Department of Linguistic and Cultural Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, 04103, Germany
| | - Salim Bourras
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland.,Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Christina Cowger
- USDA-ARS Department of Plant Pathology, North Carolina State University, Raleigh, NC, USA
| | - Paweł C Czembor
- Plant Breeding and Acclimatization Institute - National Research Institute, Radzików, 05-870 Błonie, Poland
| | - Roi Ben-David
- Department of Vegetables and Field crops, Institute of Plant Sciences, ARO-Volcani Center, Rishon LeZion, 7528809, Israel
| | - Amos Dinoor
- Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food & Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Simon R Ellwood
- Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Bentley, WA, 6102, Australia
| | - Johannes Graf
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Koichi Hatta
- Hokkaido Agricultural Research Center Field Crop Research and Development, National Agricultural Research Organization, Sapporo, Hokkaido, Japan
| | - Marcelo Helguera
- Centro de Investigaciones Agropecuarias (CIAP), INTA, Córdoba, Argentina
| | - Javier Sánchez-Martín
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Bruce A McDonald
- Plant Pathology, Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland
| | - Alexey I Morgounov
- Food and Agriculture Organization of the United Nations, Riyadh, Saudi Arabia
| | - Marion C Müller
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | | | - Kentaro K Shimizu
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.,Kihara Institute for Biological Research, Yokohama City University, Yokohama, Kanagawa, Japan
| | - Taiki Yoshihira
- Department of Sustainable Agriculture, Rakuno Gakuen University, Ebetsu, Hokkaido, Japan
| | - Helen Zbinden
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Beat Keller
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Thomas Wicker
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland.
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6
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Stalder L, Oggenfuss U, Mohd‐Assaad N, Croll D. The population genetics of adaptation through copy‐number variation in a fungal plant pathogen. Mol Ecol 2022; 32:2443-2460. [PMID: 35313056 DOI: 10.1111/mec.16435] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 03/14/2022] [Accepted: 03/16/2022] [Indexed: 11/28/2022]
Abstract
Microbial pathogens can adapt rapidly to changing environments such as the application of pesticides or host resistance. Copy number variations (CNVs) are a major source of adaptive genetic variation for recent adaptation. Here, we analyse how a major fungal pathogen of barley, Rhynchosporium commune, has adapted to the host environment and fungicide applications. We screen the genomes of 125 isolates sampled across a worldwide set of populations and identify a total of 7,879 gene duplications and 116 gene deletions. Most gene duplications result from segmental chromosomal duplications. Although CNVs are generally under negative selection, we find that genes affected by CNVs are enriched in functions related to host exploitation (i.e., effectors and cell-wall-degrading enzymes). We perform genome-wide association studies (GWAS) and identify a large segmental duplication of CYP51A that has contributed to the emergence of azole resistance and a duplication encompassing an effector gene affecting virulence. We show that the adaptive CNVs were probably created by recently active transposable element families. Moreover, we find that specific transposable element families are important drivers of recent gene CNV. Finally, we use a genome-wide single nucleotide polymorphism data set to replicate the GWAS and contrast it with the CNV-focused analysis. Together, our findings show how extensive segmental duplications create the raw material for recent adaptation in global populations of a fungal pathogen.
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Affiliation(s)
- Luzia Stalder
- Laboratory of Evolutionary Genetics Institute of Biology University of Neuchâtel 2000 Neuchâtel Switzerland
| | - Ursula Oggenfuss
- Laboratory of Evolutionary Genetics Institute of Biology University of Neuchâtel 2000 Neuchâtel Switzerland
| | - Norfarhan Mohd‐Assaad
- Plant Pathology Institute of Integrative Biology ETH, Zurich 8092 Zurich Switzerland
- Department of Applied Physics Faculty of Science and Technology Universiti Kebangsaan Malaysia 43600 Bangi Selangor Malaysia
| | - Daniel Croll
- Laboratory of Evolutionary Genetics Institute of Biology University of Neuchâtel 2000 Neuchâtel Switzerland
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7
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Wu Q, Wang Y, Liu LN, Shi K, Li CY. Comparative Genomics and Gene Pool Analysis Reveal the Decrease of Genome Diversity and Gene Number in Rice Blast Fungi by Stable Adaption with Rice. J Fungi (Basel) 2021; 8:jof8010005. [PMID: 35049945 PMCID: PMC8778285 DOI: 10.3390/jof8010005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 12/12/2021] [Accepted: 12/17/2021] [Indexed: 11/16/2022] Open
Abstract
Magnaporthe oryzae caused huge losses in rice and wheat production worldwide. Comparing to long-term co-evolution history with rice, wheat-infecting isolates were new-emerging. To reveal the genetic differences between rice and wheat blast on global genomic scale, 109 whole-genome sequences of M. oryzae from rice, wheat, and other hosts were reanalyzed in this study. We found that the rice lineage had gone through stronger selective sweep and fewer conserved genes than those of Triticum and Lolium lineages, which indicated that rice blast fungi adapted to rice by gene loss and rapid evolution of specific loci. Furthermore, 228 genes associated with host adaptation of M. oryzae were found by presence/absence variation (PAV) analyses. The functional annotation of these genes found that the fine turning of genes gain/loss involved with transport and transcription factor, thiol metabolism, and nucleotide metabolism respectively are major mechanisms for rice adaption. This result implies that genetic base of specific host plant may lead to gene gain/loss variation of pathogens, so as to enhance their adaptability to host. Further characterization of these specific loci and their roles in adaption and evaluation of the fungi may eventually lead to understanding of interaction mechanism and develop new strategies of the disease management.
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Affiliation(s)
- Qi Wu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming 650201, China; (Q.W.); (Y.W.); (L.-N.L.)
- College of Science, Yunnan Agricultural University, Kunming 650201, China
- Yunnan Organic Tea Industry Intelligent Engineering Research Center, Key Laboratory of Intelligent Organic Tea Garden Construction in Universities of Yunnan Province, Key Laboratory for Crop Production and Smart Agriculture of Yunnan Province, Yunnan Agricultural University, Kunming 650201, China
| | - Yi Wang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming 650201, China; (Q.W.); (Y.W.); (L.-N.L.)
| | - Li-Na Liu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming 650201, China; (Q.W.); (Y.W.); (L.-N.L.)
- Key Laboratory of Green Prevention and Control of Agricultural Transboundary Pests of Yunnan Province, Agricultural Environment and Resources Institute, Yunnan Academy of Agricultural Sciences, Kunming 650201, China
| | - Kai Shi
- School of Foreign Language, Yunnan Agricultural University, Kunming 650201, China;
| | - Cheng-Yun Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming 650201, China; (Q.W.); (Y.W.); (L.-N.L.)
- Correspondence:
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8
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Pereira D, Oggenfuss U, McDonald BA, Croll D. Population genomics of transposable element activation in the highly repressive genome of an agricultural pathogen. Microb Genom 2021; 7:000540. [PMID: 34424154 PMCID: PMC8549362 DOI: 10.1099/mgen.0.000540] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 02/03/2021] [Indexed: 12/13/2022] Open
Abstract
The activity of transposable elements (TEs) can be an important driver of genetic diversity with TE-mediated mutations having a wide range of fitness consequences. To avoid deleterious effects of TE activity, some fungi have evolved highly sophisticated genomic defences to reduce TE proliferation across the genome. Repeat-induced point mutation (RIP) is a fungal-specific TE defence mechanism efficiently targeting duplicated sequences. The rapid accumulation of RIPs is expected to deactivate TEs over the course of a few generations. The evolutionary dynamics of TEs at the population level in a species with highly repressive genome defences is poorly understood. Here, we analyse 366 whole-genome sequences of Parastagonospora nodorum, a fungal pathogen of wheat with efficient RIP. A global population genomics analysis revealed high levels of genetic diversity and signs of frequent sexual recombination. Contrary to expectations for a species with RIP, we identified recent TE activity in multiple populations. The TE composition and copy numbers showed little divergence among global populations regardless of the demographic history. Miniature inverted-repeat transposable elements (MITEs) and terminal repeat retrotransposons in miniature (TRIMs) were largely underlying recent intra-species TE expansions. We inferred RIP footprints in individual TE families and found that recently active, high-copy TEs have possibly evaded genomic defences. We find no evidence that recent positive selection acted on TE-mediated mutations rather that purifying selection maintained new TE insertions at low insertion frequencies in populations. Our findings highlight the complex evolutionary equilibria established by the joint action of TE activity, selection and genomic repression.
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Affiliation(s)
- Danilo Pereira
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
- Present address: Max Planck Institute for Evolutionary Biology, August-Thienemann-Straße 2, D-24306 Plön, Germany
| | - Ursula Oggenfuss
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Bruce A. McDonald
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
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9
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Chen JY, Zhang DD, Huang JQ, Li R, Wang D, Song J, Puri KD, Yang L, Kong ZQ, Tong BZ, Li JJ, Huang YS, Simko I, Klosterman SJ, Dai XF, Subbarao KV. Dynamics of Verticillium dahliae race 1 population under managed agricultural ecosystems. BMC Biol 2021; 19:131. [PMID: 34172070 PMCID: PMC8235872 DOI: 10.1186/s12915-021-01061-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 06/01/2021] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Plant pathogens and their hosts undergo adaptive changes in managed agricultural ecosystems, by overcoming host resistance, but the underlying genetic adaptations are difficult to determine in natural settings. Verticillium dahliae is a fungal pathogen that causes Verticillium wilt on many economically important crops including lettuce. We assessed the dynamics of changes in the V. dahliae genome under selection in a long-term field experiment. RESULTS In this study, a field was fumigated before the Verticillium dahliae race 1 strain (VdLs.16) was introduced. A derivative 145-strain population was collected over a 6-year period from this field in which a seggregating population of lettuce derived from Vr1/vr1 parents were evaluated. We de novo sequenced the parental genome of VdLs.16 strain and resequenced the derivative strains to analyze the genetic variations that accumulate over time in the field cropped with lettuce. Population genomics analyses identified 2769 single-nucleotide polymorphisms (SNPs) and 750 insertion/deletions (In-Dels) in the 145 isolates compared with the parental genome. Sequence divergence was identified in the coding sequence regions of 378 genes and in the putative promoter regions of 604 genes. Five-hundred and nine SNPs/In-Dels were identified as fixed. The SNPs and In-Dels were significantly enriched in the transposon-rich, gene-sparse regions, and in those genes with functional roles in signaling and transcriptional regulation. CONCLUSIONS Under the managed ecosystem continuously cropped to lettuce, the local adaptation of V. dahliae evolves at a whole genome scale to accumulate SNPs/In-Dels nonrandomly in hypervariable regions that encode components of signal transduction and transcriptional regulation.
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Affiliation(s)
- Jie-Yin Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Dan-Dan Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | | | - Ran Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Dan Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jian Song
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Krishna D Puri
- Department of Plant Pathology, University of California, Davis, c/o U.S. Agricultural Research Station, Salinas, CA, USA
| | - Lin Yang
- BGI-Shenzhen, Shenzhen, Guangdong, China
| | - Zhi-Qiang Kong
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | | | - Jun-Jiao Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | | | - Ivan Simko
- United States Department of Agriculture, Agricultural Research Service, Crop Improvement and Protection Research Unit, Salinas, CA, USA
| | - Steven J Klosterman
- United States Department of Agriculture, Agricultural Research Service, Crop Improvement and Protection Research Unit, Salinas, CA, USA.
| | - Xiao-Feng Dai
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
| | - Krishna V Subbarao
- Department of Plant Pathology, University of California, Davis, c/o U.S. Agricultural Research Station, Salinas, CA, USA.
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10
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Ma F, Lau CY, Zheng C. Large genetic diversity and strong positive selection in F-box and GPCR genes among the wild isolates of Caenorhabditis elegans. Genome Biol Evol 2021; 13:6163285. [PMID: 33693740 PMCID: PMC8120010 DOI: 10.1093/gbe/evab048] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 02/17/2021] [Accepted: 03/03/2021] [Indexed: 01/05/2023] Open
Abstract
The F-box and chemosensory GPCR (csGPCR) gene families are greatly expanded in nematodes, including the model organism Caenorhabditis elegans, compared with insects and vertebrates. However, the intraspecific evolution of these two gene families in nematodes remain unexamined. In this study, we analyzed the genomic sequences of 330 recently sequenced wild isolates of C. elegans using a range of population genetics approaches. We found that F-box and csGPCR genes, especially the Srw family csGPCRs, showed much more diversity than other gene families. Population structure analysis and phylogenetic analysis divided the wild strains into eight non-Hawaiian and three Hawaiian subpopulations. Some Hawaiian strains appeared to be more ancestral than all other strains. F-box and csGPCR genes maintained a great amount of the ancestral variants in the Hawaiian subpopulation and their divergence among the non-Hawaiian subpopulations contributed significantly to population structure. F-box genes are mostly located at the chromosomal arms and high recombination rate correlates with their large polymorphism. Moreover, using both neutrality tests and extended haplotype homozygosity analysis, we identified signatures of strong positive selection in the F-box and csGPCR genes among the wild isolates, especially in the non-Hawaiian population. Accumulation of high-frequency-derived alleles in these genes was found in non-Hawaiian population, leading to divergence from the ancestral genotype. In summary, we found that F-box and csGPCR genes harbor a large pool of natural variants, which may be subjected to positive selection. These variants are mostly mapped to the substrate-recognition domains of F-box proteins and the extracellular and intracellular regions of csGPCRs, possibly resulting in advantages during adaptation by affecting protein degradation and the sensing of environmental cues, respectively.
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Affiliation(s)
- Fuqiang Ma
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China
| | - Chun Yin Lau
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China
| | - Chaogu Zheng
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China
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11
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Duan G, Bao J, Chen X, Xie J, Liu Y, Chen H, Zheng H, Tang W, Wang Z. Large-Scale Genome Scanning within Exonic Regions Revealed the Contributions of Selective Sweep Prone Genes to Host Divergence and Adaptation in Magnaporthe oryzae Species Complex. Microorganisms 2021; 9:562. [PMID: 33803140 PMCID: PMC8000120 DOI: 10.3390/microorganisms9030562] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 03/05/2021] [Accepted: 03/06/2021] [Indexed: 11/30/2022] Open
Abstract
Magnaporthe oryzae, one of the most notorious plant pathogens in the agronomic ecosystem, causes a destructive rice blast disease around the world. The blast fungus infects wide arrays of cultivated and non-cultivated plants within the Poaceae. Studies have shown that host speciation exerts selection pressure that drives the evolution and divergence of the M. oryzae population. Population genetic relationship deducted by genome-wide single nucleotide polymorphisms showed that M. oryzae differentiation is highly consistent with the host speciation process. In particular, the rice-infecting population of M. oryzae is distinct from populations from other hosts. However, how genome regions prone to host-mediated selection pressures associated with speciation in M. oryzae, especially at a large-scale population level, has not been extensively characterized. Here, we detected strong evidence of sweep selection throughout the genomes of rice and non-rice pathotypes of M. oryzae population using integrated haplotype score (iHS), cross population extended haplotype homozygosity (XPEHH), and cross population composite likelihood ratio (XPCLR) tests. Functional annotation analyses of the genes associated with host-mediated selection pressure showed that 14 pathogenicity-related genes are under positive selection pressure. Additionally, we showed that 17 candidate effector proteins are under positive and divergent selection among the blast fungus population through sweep selection analysis. Specifically, we find that a divergent selective gene, MGG_13871, is experiencing host-directed mutation in two amino acid residues in rice and non-rice infecting populations. These results provide a crucial insight into the impact of selective sweeping on the differentiation of M. oryzae populations and the dynamic influences of genomic regions in promoting host adaptation and speciation among M. oryzae species.
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Affiliation(s)
- Guohua Duan
- State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, The School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (G.D.); (J.B.); (X.C.); (J.X.); (Y.L.); (H.C.); (H.Z.)
- Fujian Universities Key Laboratory for Plant-Microbe Interaction, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Jiandong Bao
- State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, The School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (G.D.); (J.B.); (X.C.); (J.X.); (Y.L.); (H.C.); (H.Z.)
| | - Xiaomin Chen
- State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, The School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (G.D.); (J.B.); (X.C.); (J.X.); (Y.L.); (H.C.); (H.Z.)
- Fujian Universities Key Laboratory for Plant-Microbe Interaction, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Jiahui Xie
- State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, The School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (G.D.); (J.B.); (X.C.); (J.X.); (Y.L.); (H.C.); (H.Z.)
- Fujian Universities Key Laboratory for Plant-Microbe Interaction, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yuchan Liu
- State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, The School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (G.D.); (J.B.); (X.C.); (J.X.); (Y.L.); (H.C.); (H.Z.)
| | - Huiquan Chen
- State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, The School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (G.D.); (J.B.); (X.C.); (J.X.); (Y.L.); (H.C.); (H.Z.)
- Fuzhou Institute of Oceanography, Minjiang University, Fuzhou 350108, China
| | - Huakun Zheng
- State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, The School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (G.D.); (J.B.); (X.C.); (J.X.); (Y.L.); (H.C.); (H.Z.)
- Fujian Universities Key Laboratory for Plant-Microbe Interaction, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Wei Tang
- State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, The School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (G.D.); (J.B.); (X.C.); (J.X.); (Y.L.); (H.C.); (H.Z.)
- Fujian Universities Key Laboratory for Plant-Microbe Interaction, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Zonghua Wang
- State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, The School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (G.D.); (J.B.); (X.C.); (J.X.); (Y.L.); (H.C.); (H.Z.)
- Fujian Universities Key Laboratory for Plant-Microbe Interaction, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Fuzhou Institute of Oceanography, Minjiang University, Fuzhou 350108, China
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12
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Carlier J, Bonnot F, Roussel V, Ravel S, Martinez RT, Perez-Vicente L, Abadie C, Wright S. Convergent Adaptation to Quantitative Host Resistance in a Major Plant Pathogen. mBio 2021; 12:e03129-20. [PMID: 33622734 DOI: 10.1128/mBio.03129-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Plant pathogens can adapt to quantitative resistance, eroding its effectiveness. The aim of this work was to reveal the genomic basis of adaptation to such a resistance in populations of the fungus Pseudocercospora fijiensis, a major devastating pathogen of banana, by studying convergent adaptation on different cultivars. Samples from P. fijiensis populations showing a local adaptation pattern on new banana hybrids with quantitative resistance were compared, based on a genome scan approach, with samples from traditional and more susceptible cultivars in Cuba and the Dominican Republic. Whole-genome sequencing of pools of P. fijiensis isolates (pool-seq) sampled from three locations per country was conducted according to a paired population design. The findings of different combined analyses highly supported the existence of convergent adaptation on the study cultivars between locations within but not between countries. Five to six genomic regions involved in this adaptation were detected in each country. An annotation analysis and available biological data supported the hypothesis that some genes within the detected genomic regions may play a role in quantitative pathogenicity, including gene regulation. The results suggested that the genetic basis of fungal adaptation to quantitative plant resistance is at least oligogenic, while highlighting the existence of specific host-pathogen interactions for this kind of resistance.IMPORTANCE Understanding the genetic basis of pathogen adaptation to quantitative resistance in plants has a key role to play in establishing durable strategies for resistance deployment. In this context, a population genomic approach was developed for a major plant pathogen (the fungus Pseudocercospora fijiensis causing black leaf streak disease of banana) whereby samples from new resistant banana hybrids were compared with samples from more susceptible conventional cultivars in two countries. A total of 11 genomic regions for which there was strong evidence of selection by quantitative resistance were detected. An annotation analysis and available biological data supported the hypothesis that some of the genes within these regions may play a role in quantitative pathogenicity. These results suggested a polygenic basis of quantitative pathogenicity in this fungal pathogen and complex molecular plant-pathogen interactions in quantitative disease development involving several genes on both sides.
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13
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Hartmann FE, Rodríguez de la Vega RC, Gladieux P, Ma WJ, Hood ME, Giraud T. Higher Gene Flow in Sex-Related Chromosomes than in Autosomes during Fungal Divergence. Mol Biol Evol 2020; 37:668-682. [PMID: 31651949 PMCID: PMC7038665 DOI: 10.1093/molbev/msz252] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Nonrecombining sex chromosomes are widely found to be more differentiated than autosomes among closely related species, due to smaller effective population size and/or to a disproportionally large-X effect in reproductive isolation. Although fungal mating-type chromosomes can also display large nonrecombining regions, their levels of differentiation compared with autosomes have been little studied. Anther-smut fungi from the Microbotryum genus are castrating pathogens of Caryophyllaceae plants with largely nonrecombining mating-type chromosomes. Using whole genome sequences of 40 fungal strains, we quantified genetic differentiation among strains isolated from the geographically overlapping North American species and subspecies of Silene virginica and S. caroliniana. We inferred that gene flow likely occurred at the early stages of divergence and then completely stopped. We identified large autosomal genomic regions with chromosomal inversions, with higher genetic divergence than the rest of the genomes and highly enriched in selective sweeps, supporting a role of rearrangements in preventing gene flow in genomic regions involved in ecological divergence. Unexpectedly, the nonrecombining mating-type chromosomes showed lower divergence than autosomes due to higher gene flow, which may be promoted by adaptive introgressions of less degenerated mating-type chromosomes. The fact that both mating-type chromosomes are always heterozygous and nonrecombining may explain such patterns that oppose to those found for XY or ZW sex chromosomes. The specific features of mating-type chromosomes may also apply to the UV sex chromosomes determining sexes at the haploid stage in algae and bryophytes and may help test general hypotheses on the evolutionary specificities of sex-related chromosomes.
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Affiliation(s)
- Fanny E Hartmann
- Ecologie Systematique Evolution, Batiment 360, Univ. Paris-Sud, AgroParisTech, CNRS, Université Paris-Saclay, Orsay, France
| | - Ricardo C Rodríguez de la Vega
- Ecologie Systematique Evolution, Batiment 360, Univ. Paris-Sud, AgroParisTech, CNRS, Université Paris-Saclay, Orsay, France
| | - Pierre Gladieux
- UMR BGPI, Univ Montpellier, INRA, CIRAD, Montpellier SupAgro, Montpellier, France
| | - Wen-Juan Ma
- Biology Department, Science Centre, Amherst College, Amherst, MA
| | - Michael E Hood
- Biology Department, Science Centre, Amherst College, Amherst, MA
| | - Tatiana Giraud
- Ecologie Systematique Evolution, Batiment 360, Univ. Paris-Sud, AgroParisTech, CNRS, Université Paris-Saclay, Orsay, France
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14
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Abstract
Studies in diverse biological systems have indicated that host-parasite co-evolution is responsible for the extraordinary genetic diversity seen in some genomic regions, such as major histocompatibility (MHC) genes in jawed vertebrates and resistance genes in plants. This diversity is believed to evolve under balancing selection on hosts by parasites. However, the mechanisms that link the genomic signatures in these regions to the underlying co-evolutionary process are only slowly emerging. We still lack a clear picture of the co-evolutionary concepts and of the genetic basis of the co-evolving phenotypic traits in the interacting antagonists. Emerging genomic tools that provide new options for identifying underlying genes will contribute to a fuller understanding of the co-evolutionary process.
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Affiliation(s)
- Dieter Ebert
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland. .,Wissenschaftskolleg zu Berlin, Berlin, Germany.
| | - Peter D Fields
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland
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15
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de Vries S, Stukenbrock EH, Rose LE. Rapid evolution in plant-microbe interactions - an evolutionary genomics perspective. New Phytol 2020; 226:1256-1262. [PMID: 31997351 DOI: 10.1111/nph.16458] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 01/13/2020] [Indexed: 05/22/2023]
Abstract
Access to greater genomic resolution through new sequencing technologies is transforming the field of plant pathology. As scientists embrace these new methods, some overarching patterns and observations come into focus. Evolutionary genomic studies are used to determine not only the origins of pathogen lineages and geographic patterns of genetic diversity, but also to discern how natural selection structures genetic variation across the genome. With greater and greater resolution, we can now pinpoint the targets of selection on a large scale. At multiple levels, crypsis and convergent evolution are evident. Host jumps and shifts may be more pervasive than once believed, and hybridization and horizontal gene transfer (HGT) likely play important roles in the emergence of genetic novelty.
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Affiliation(s)
- Sophie de Vries
- Institute of Population Genetics, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Eva H Stukenbrock
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, Plön, Germany
- The Botanical Institute, Christian-Albrechts University of Kiel, Am Botanischen Garden 9-11, 24118, Kiel, Germany
| | - Laura E Rose
- Institute of Population Genetics, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
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16
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Derbyshire MC. Bioinformatic Detection of Positive Selection Pressure in Plant Pathogens: The Neutral Theory of Molecular Sequence Evolution in Action. Front Microbiol 2020; 11:644. [PMID: 32328056 PMCID: PMC7160247 DOI: 10.3389/fmicb.2020.00644] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 03/20/2020] [Indexed: 11/13/2022] Open
Abstract
The genomes of plant pathogenic fungi and oomycetes are often exposed to strong positive selection pressure. During speciation, shifts in host range and preference can lead to major adaptive changes. Furthermore, evolution of total host resistance to most isolates can force rapid evolutionary changes in host-specific pathogens. Crop pathogens are subjected to particularly intense selective pressures from monocultures and fungicides. Detection of the footprints of positive selection in plant pathogen genomes is a worthwhile endeavor as it aids understanding of the fundamental biology of these important organisms. There are two main classes of test for detection of positively selected alleles. Tests based on the ratio of non-synonymous to synonymous substitutions per site detect the footprints of multiple fixation events between divergent lineages. Thus, they are well-suited to the study of ancient adaptation events spanning speciations. On the other hand, tests that scan genomes for local fluctuations in allelic diversity within populations are suitable for detection of recent positive selection in populations. In this review, I briefly describe some of the more widely used tests of positive selection and the theory underlying them. I then discuss various examples of their application to plant pathogen genomes, emphasizing the types of genes that are associated with signatures of positive selection. I conclude with a discussion of the practicality of such tests for identification of pathogen genes of interest and the important features of pathogen ecology that must be taken into account for accurate interpretation.
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Affiliation(s)
- Mark C Derbyshire
- Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Perth, WA, Australia
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17
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Quibod IL, Atieza-Grande G, Oreiro EG, Palmos D, Nguyen MH, Coronejo ST, Aung EE, Nugroho C, Roman-Reyna V, Burgos MR, Capistrano P, Dossa SG, Onaga G, Saloma C, Cruz CV, Oliva R. The Green Revolution shaped the population structure of the rice pathogen Xanthomonas oryzae pv. oryzae. ISME J 2020; 14:492-505. [PMID: 31666657 DOI: 10.1038/s41396-019-0545-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 10/15/2019] [Accepted: 10/17/2019] [Indexed: 11/15/2022]
Abstract
The impact of modern agriculture on the evolutionary trajectory of plant pathogens is a central question for crop sustainability. The Green Revolution replaced traditional rice landraces with high-yielding varieties, creating a uniform selection pressure that allows measuring the effect of such intervention. In this study, we analyzed a unique historical pathogen record to assess the impact of a major resistance gene, Xa4, in the population structure of Xanthomonas oryzae pv. oryzae (Xoo) collected in the Philippines in a span of 40 years. After the deployment of Xa4 in the early 1960s, the emergence of virulent pathogen groups was associated with the increasing adoption of rice varieties carrying Xa4, which reached 80% of the total planted area. Whole genomes analysis of a representative sample suggested six major pathogen groups with distinctive signatures of selection in genes related to secretion system, cell-wall degradation, lipopolysaccharide production, and detoxification of host defense components. Association genetics also suggested that each population might evolve different mechanisms to adapt to Xa4. Interestingly, we found evidence of strong selective sweep affecting several populations in the mid-1980s, suggesting a major bottleneck that coincides with the peak of Xa4 deployment in the archipelago. Our study highlights how modern agricultural practices facilitate the adaptation of pathogens to overcome the effects of standard crop improvement efforts.
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18
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Richards JK, Stukenbrock EH, Carpenter J, Liu Z, Cowger C, Faris JD, Friesen TL. Local adaptation drives the diversification of effectors in the fungal wheat pathogen Parastagonospora nodorum in the United States. PLoS Genet 2019; 15:e1008223. [PMID: 31626626 PMCID: PMC6821140 DOI: 10.1371/journal.pgen.1008223] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 10/30/2019] [Accepted: 08/25/2019] [Indexed: 12/22/2022] Open
Abstract
Filamentous fungi rapidly evolve in response to environmental selection pressures in part due to their genomic plasticity. Parastagonospora nodorum, a fungal pathogen of wheat and causal agent of septoria nodorum blotch, responds to selection pressure exerted by its host, influencing the gain, loss, or functional diversification of virulence determinants, known as effector genes. Whole genome resequencing of 197 P. nodorum isolates collected from spring, durum, and winter wheat production regions of the United States enabled the examination of effector diversity and genomic regions under selection specific to geographically discrete populations. 1,026,859 SNPs/InDels were used to identify novel loci, as well as SnToxA and SnTox3 as factors in disease. Genes displaying presence/absence variation, predicted effector genes, and genes localized on an accessory chromosome had significantly higher pN/pS ratios, indicating a higher rate of sequence evolution. Population structure analyses indicated two P. nodorum populations corresponding to the Upper Midwest (Population 1) and Southern/Eastern United States (Population 2). Prevalence of SnToxA varied greatly between the two populations which correlated with presence of the host sensitivity gene Tsn1 in the most prevalent cultivars in the corresponding regions. Additionally, 12 and 5 candidate effector genes were observed to be under diversifying selection among isolates from Population 1 and 2, respectively, but under purifying selection or neutrally evolving in the opposite population. Selective sweep analysis revealed 10 and 19 regions that had recently undergone positive selection in Population 1 and 2, respectively, involving 92 genes in total. When comparing genes with and without presence/absence variation, those genes exhibiting this variation were significantly closer to transposable elements. Taken together, these results indicate that P. nodorum is rapidly adapting to distinct selection pressures unique to spring and winter wheat production regions by rapid adaptive evolution and various routes of genomic diversification, potentially facilitated through transposable element activity.
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Affiliation(s)
- Jonathan K. Richards
- Department of Plant Pathology and Crop Physiology, Louisiana State University Agricultural Center, Baton Rouge, Louisiana, United States of America
| | - Eva H. Stukenbrock
- Department of Environmental Genomics, Christian-Albrechts University of Kiel, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Jessica Carpenter
- Department of Plant Pathology, North Dakota State University, Fargo, North Dakota, United States of America
| | - Zhaohui Liu
- Department of Plant Pathology, North Dakota State University, Fargo, North Dakota, United States of America
| | - Christina Cowger
- Plant Science Research Unit, USDA-ARS, Raleigh, North Carolina, United States of America
| | - Justin D. Faris
- Cereal Crops Research Unit, Edward T. Schaefer Agricultural Research Center, USDA-ARS, Fargo, North Dakota, United States of America
| | - Timothy L. Friesen
- Department of Plant Pathology, North Dakota State University, Fargo, North Dakota, United States of America
- Cereal Crops Research Unit, Edward T. Schaefer Agricultural Research Center, USDA-ARS, Fargo, North Dakota, United States of America
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19
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Hartmann FE, Rodríguez de la Vega RC, Carpentier F, Gladieux P, Cornille A, Hood ME, Giraud T. Understanding Adaptation, Coevolution, Host Specialization, and Mating System in Castrating Anther-Smut Fungi by Combining Population and Comparative Genomics. Annu Rev Phytopathol 2019; 57:431-457. [PMID: 31337277 DOI: 10.1146/annurev-phyto-082718-095947] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Anther-smut fungi provide a powerful system to study host-pathogen specialization and coevolution, with hundreds of Microbotryum species specialized on diverse Caryophyllaceae plants, castrating their hosts through manipulation of the hosts' reproductive organs to facilitate disease transmission. Microbotryum fungi have exceptional genomic characteristics, including dimorphic mating-type chromosomes, that make this genus anexcellent model for studying the evolution of mating systems and their influence on population genetics structure and adaptive potential. Important insights into adaptation, coevolution, host specialization, and mating system evolution have been gained using anther-smut fungi, with new insights made possible by the recent advent of genomic approaches. We illustrate with Microbotryum case studies how using a combination of comparative genomics, population genomics, and transcriptomics approaches enables the integration of different evolutionary perspectives across different timescales. We also highlight current challenges and suggest future studies that will contribute to advancing our understanding of the mechanisms underlying adaptive processes in populations of fungal pathogens.
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Affiliation(s)
- Fanny E Hartmann
- Ecologie Systématique Evolution, Univ. Paris-Sud, AgroParisTech, CNRS, Université Paris-Saclay, 91400 Orsay, France;
| | | | - Fantin Carpentier
- Ecologie Systématique Evolution, Univ. Paris-Sud, AgroParisTech, CNRS, Université Paris-Saclay, 91400 Orsay, France;
| | - Pierre Gladieux
- UMR BGPI, Univ. Montpellier, INRA, CIRAD, Montpellier SupAgro, 34398 Montpellier, France
| | - Amandine Cornille
- Génétique Quantitative et Evolution-Le Moulon, INRA; Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91198 Gif-sur-Yvette, France
| | - Michael E Hood
- Biology Department, Amherst College, Amherst, Massachusetts 01002-5000, USA
| | - Tatiana Giraud
- Ecologie Systématique Evolution, Univ. Paris-Sud, AgroParisTech, CNRS, Université Paris-Saclay, 91400 Orsay, France;
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20
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Mohd-Assaad N, McDonald BA, Croll D. The emergence of the multi-species NIP1 effector in Rhynchosporium was accompanied by high rates of gene duplications and losses. Environ Microbiol 2019; 21:2677-2695. [PMID: 30838748 DOI: 10.1111/1462-2920.14583] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 02/23/2019] [Accepted: 03/04/2019] [Indexed: 01/28/2023]
Abstract
Plant pathogens secrete effector proteins to manipulate the host and facilitate infection. Cognate hosts trigger strong defence responses upon detection of these effectors. Consequently, pathogens and hosts undergo rapid coevolutionary arms races driven by adaptive evolution of effectors and receptors. Because of their high rate of turnover, most effectors are thought to be species-specific and the evolutionary trajectories are poorly understood. Here, we investigate the necrosis-inducing protein 1 (NIP1) effector in the multihost pathogen genus Rhynchosporium. We retraced the evolutionary history of the NIP1 locus using whole-genome assemblies of 146 strains covering four closely related species. NIP1 orthologues were present in all species but the locus consistently segregated presence-absence polymorphisms suggesting long-term balancing selection. We also identified previously unknown paralogues of NIP1 that were shared among multiple species and showed substantial copy-number variation within R. commune. The NIP1A paralogue was under significant positive selection suggesting that NIP1A is the dominant effector variant coevolving with host immune receptors. Consistent with this prediction, we found that copy number variation at NIP1A had a stronger effect on virulence than NIP1B. Our analyses unravelled the origins and diversification mechanisms of a pathogen effector family shedding light on how pathogens gain adaptive genetic variation.
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Affiliation(s)
- Norfarhan Mohd-Assaad
- Plant Pathology, Institute of Integrative Biology, ETH, Zurich, 8092 Zurich, Switzerland.,School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
| | - Bruce A McDonald
- Plant Pathology, Institute of Integrative Biology, ETH, Zurich, 8092 Zurich, Switzerland
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, 2000 Neuchâtel, Switzerland
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21
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Derbyshire MC, Denton-Giles M, Hane JK, Chang S, Mousavi-Derazmahalleh M, Raffaele S, Buchwaldt L, Kamphuis LG. A whole genome scan of SNP data suggests a lack of abundant hard selective sweeps in the genome of the broad host range plant pathogenic fungus Sclerotinia sclerotiorum. PLoS One 2019; 14:e0214201. [PMID: 30921376 PMCID: PMC6438532 DOI: 10.1371/journal.pone.0214201] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 03/10/2019] [Indexed: 01/08/2023] Open
Abstract
The pathogenic fungus Sclerotinia sclerotiorum infects over 600 species of plant. It is present in numerous environments throughout the world and causes significant damage to many agricultural crops. Fragmentation and lack of gene flow between populations may lead to population sub-structure. Within discrete recombining populations, positive selection may lead to a ‘selective sweep’. This is characterised by an increase in frequency of a favourable allele leading to reduction in genotypic diversity in a localised genomic region due to the phenomenon of genetic hitchhiking. We aimed to assess whether isolates of S. sclerotiorum from around the world formed genotypic clusters associated with geographical origin and to determine whether signatures of population-specific positive selection could be detected. To do this, we sequenced the genomes of 25 isolates of S. sclerotiorum collected from four different continents–Australia, Africa (north and south), Europe and North America (Canada and the northen United States) and conducted SNP based analyses of population structure and selective sweeps. Among the 25 isolates, there was evidence for two major population clusters. One of these consisted of 11 isolates from Canada, the USA and France (population 1), and the other consisted of nine isolates from Australia and one from Morocco (population 2). The rest of the isolates were genotypic outliers. We found that there was evidence of outcrossing in these two populations based on linkage disequilibrium decay. However, only a single candidate selective sweep was observed, and it was present in population 2. This sweep was close to a Major Facilitator Superfamily transporter gene, and we speculate that this gene may have a role in nutrient uptake from the host. The low abundance of selective sweeps in the S. sclerotiorum genome contrasts the numerous examples in the genomes of other fungal pathogens. This may be a result of its slow rate of evolution and low effective recombination rate due to self-fertilisation and vegetative reproduction.
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Affiliation(s)
- Mark Charles Derbyshire
- Centre for Crop and Disease Management, Curtin University, Perth, Western Australia, Australia
- * E-mail:
| | - Matthew Denton-Giles
- Centre for Crop and Disease Management, Curtin University, Perth, Western Australia, Australia
| | - James K. Hane
- Centre for Crop and Disease Management, Curtin University, Perth, Western Australia, Australia
| | - Steven Chang
- Centre for Crop and Disease Management, Curtin University, Perth, Western Australia, Australia
| | - Mahsa Mousavi-Derazmahalleh
- Centre for Crop and Disease Management, Curtin University, Perth, Western Australia, Australia
- UWA School of Agriculture and Environment, The University of Western Australia, Perth, Western Australia, Australia
| | - Sylvain Raffaele
- Laboratoire des Interactions Plantes-Micro-organismes (LIPM), Université de Toulouse, INRA, Toulouse, France
| | - Lone Buchwaldt
- Agriculture and Agri-Food Canada, Saskatoon Research and Development Centre, Saskatchewan, Saskatoon, Canada
| | - Lars G. Kamphuis
- Centre for Crop and Disease Management, Curtin University, Perth, Western Australia, Australia
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Sánchez-Vallet A, Fouché S, Fudal I, Hartmann FE, Soyer JL, Tellier A, Croll D. The Genome Biology of Effector Gene Evolution in Filamentous Plant Pathogens. Annu Rev Phytopathol 2018; 56:21-40. [PMID: 29768136 DOI: 10.1146/annurev-phyto-080516-035303] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Filamentous pathogens, including fungi and oomycetes, pose major threats to global food security. Crop pathogens cause damage by secreting effectors that manipulate the host to the pathogen's advantage. Genes encoding such effectors are among the most rapidly evolving genes in pathogen genomes. Here, we review how the major characteristics of the emergence, function, and regulation of effector genes are tightly linked to the genomic compartments where these genes are located in pathogen genomes. The presence of repetitive elements in these compartments is associated with elevated rates of point mutations and sequence rearrangements with a major impact on effector diversification. The expression of many effectors converges on an epigenetic control mediated by the presence of repetitive elements. Population genomics analyses showed that rapidly evolving pathogens show high rates of turnover at effector loci and display a mosaic in effector presence-absence polymorphism among strains. We conclude that effective pathogen containment strategies require a thorough understanding of the effector genome biology and the pathogen's potential for rapid adaptation.
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Affiliation(s)
- Andrea Sánchez-Vallet
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, 8092 Zürich, Switzerland
| | - Simone Fouché
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, 8092 Zürich, Switzerland
| | - Isabelle Fudal
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, 78850 Thiverval-Grignon, France
| | - Fanny E Hartmann
- Ecologie Systématique Evolution, AgroParisTech, Université Paris-Sud, CNRS, Université Paris-Saclay, 91400 Orsay, France
| | - Jessica L Soyer
- UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, 78850 Thiverval-Grignon, France
| | - Aurélien Tellier
- Section of Population Genetics, Technical University of Munich, 85354 Freising, Germany
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, 2000 Neuchâtel, Switzerland;
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