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Tralamazza SM, Gluck-Thaler E, Feurtey A, Croll D. Copy number variation introduced by a massive mobile element facilitates global thermal adaptation in a fungal wheat pathogen. Nat Commun 2024; 15:5728. [PMID: 38977688 PMCID: PMC11231334 DOI: 10.1038/s41467-024-49913-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 06/25/2024] [Indexed: 07/10/2024] Open
Abstract
Copy number variation (CNV) can drive rapid evolution in changing environments. In microbial pathogens, such adaptation is a key factor underpinning epidemics and colonization of new niches. However, the genomic determinants of such adaptation remain poorly understood. Here, we systematically investigate CNVs in a large genome sequencing dataset spanning a worldwide collection of 1104 genomes from the major wheat pathogen Zymoseptoria tritici. We found overall strong purifying selection acting on most CNVs. Genomic defense mechanisms likely accelerated gene loss over episodes of continental colonization. Local adaptation along climatic gradients was likely facilitated by CNVs affecting secondary metabolite production and gene loss in general. One of the strongest loci for climatic adaptation is a highly conserved gene of the NAD-dependent Sirtuin family. The Sirtuin CNV locus localizes to an ~68-kb Starship mobile element unique to the species carrying genes highly expressed during plant infection. The element has likely lost the ability to transpose, demonstrating how the ongoing domestication of cargo-carrying selfish elements can contribute to selectable variation within populations. Our work highlights how standing variation in gene copy numbers at the global scale can be a major factor driving climatic and metabolic adaptation in microbial species.
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Affiliation(s)
- Sabina Moser Tralamazza
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, CH-2000, Neuchâtel, Switzerland
| | - Emile Gluck-Thaler
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, CH-2000, Neuchâtel, Switzerland
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, USA
| | - Alice Feurtey
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, CH-2000, Neuchâtel, Switzerland
- Plant Pathology, D-USYS, ETH Zurich, CH-8092, Zurich, Switzerland
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, CH-2000, Neuchâtel, Switzerland.
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2
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Wacker T, Helmstetter N, Studholme DJ, Farrer RA. Genome variation in the Batrachochytrium pathogens of amphibians. PLoS Pathog 2024; 20:e1012218. [PMID: 38781266 PMCID: PMC11115238 DOI: 10.1371/journal.ppat.1012218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2024] Open
Affiliation(s)
- Theresa Wacker
- Biosciences, University of Exeter, Exeter, United Kingdom
| | - Nicolas Helmstetter
- Medical Research Council Centre for Medical Mycology at the University of Exeter, Exeter, United Kingdom
| | | | - Rhys A. Farrer
- Medical Research Council Centre for Medical Mycology at the University of Exeter, Exeter, United Kingdom
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3
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Verster R, Ghosh PN, Sewell TR, Garner TWJ, Fisher MC, Muller W, Cilliers D, Weldon C. Environment predicts Batrachochytrium dendrobatidis lineage distribution and zones of recombination in South Africa. Ecol Evol 2024; 14:e11037. [PMID: 38390004 PMCID: PMC10883246 DOI: 10.1002/ece3.11037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 01/10/2024] [Accepted: 02/02/2024] [Indexed: 02/24/2024] Open
Abstract
The amphibian-infecting chytrid fungus, Batrachochytrium dendrobatidis (Bd), is widespread throughout Africa and is linked to declines of populations and species across the continent. While it is well established that the lineage of Bd encodes traits which determine disease severity, knowledge around how lineages are distributed according to environmental envelope is unclear. We here studied the distribution of Bd in South Africa based on the two lineages found, BdGPL and BdCAPE, in terms of their genome and environmental envelope statistically associated with their distribution. We used Bd surveillance data from published studies, as well as data collected during fieldwork from across South Africa, Lesotho, and eSwatini with samples collected along a transect spanning most of South Africa from Lesotho to the west coast. We utilized lineage-typing qPCR to resolve the spatial distribution of BdGPL and BdCAPE across South Africa and used the resulting surveillance data to create a predictive ecological niche model for Bd lineages in South Africa. Phylogenomic analyses were performed on isolates sourced from across the transect. We show that BdGPL demonstrates a strong isolation by distance suggestive of stepping-stone dispersal, while BdCAPE showed two distinct clusters within their genomic structure that appear geographically and temporally clustered, indicating two separate invasions. Our predictive niche model revealed that the two lineages tended to occur in different ecotypes; BdGPL was associated with lower altitude, arid regions while BdCAPE occurred across cooler, higher altitude environs. Niche predictions identified a zone of lineage contact, where genomics identified inter-lineage recombinants. We argue that this zone of recombination should be prioritized for disease surveillance as it is a potential hotspot for the evolution of variants of amphibian chytrid with novel traits that may be epidemiologically relevant.
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Affiliation(s)
- Ruhan Verster
- Unit for Environmental Sciences and Management North-West University Potchefstroom South Africa
| | - Pria N Ghosh
- Unit for Environmental Sciences and Management North-West University Potchefstroom South Africa
- MRC Centre for Global Infectious Disease Analysis, School of Public Health Imperial College London London UK
| | - Tom R Sewell
- MRC Centre for Global Infectious Disease Analysis, School of Public Health Imperial College London London UK
| | - Trenton W J Garner
- Unit for Environmental Sciences and Management North-West University Potchefstroom South Africa
- Institute of Zoology Zoological Society of London London UK
| | - Matthew C Fisher
- MRC Centre for Global Infectious Disease Analysis, School of Public Health Imperial College London London UK
| | - Wynand Muller
- Unit for Environmental Sciences and Management North-West University Potchefstroom South Africa
| | - Dirk Cilliers
- Unit for Environmental Sciences and Management North-West University Potchefstroom South Africa
| | - Ché Weldon
- Unit for Environmental Sciences and Management North-West University Potchefstroom South Africa
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4
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Albanaz ATS, Carrington M, Frolov AO, Ganyukova AI, Gerasimov ES, Kostygov AY, Lukeš J, Malysheva MN, Votýpka J, Zakharova A, Záhonová K, Zimmer SL, Yurchenko V, Butenko A. Shining the spotlight on the neglected: new high-quality genome assemblies as a gateway to understanding the evolution of Trypanosomatidae. BMC Genomics 2023; 24:471. [PMID: 37605127 PMCID: PMC10441713 DOI: 10.1186/s12864-023-09591-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 08/15/2023] [Indexed: 08/23/2023] Open
Abstract
BACKGROUND Protists of the family Trypanosomatidae (phylum Euglenozoa) have gained notoriety as parasites affecting humans, domestic animals, and agricultural plants. However, the true extent of the group's diversity spreads far beyond the medically and veterinary relevant species. We address several knowledge gaps in trypanosomatid research by undertaking sequencing, assembly, and analysis of genomes from previously overlooked representatives of this protistan group. RESULTS We assembled genomes for twenty-one trypanosomatid species, with a primary focus on insect parasites and Trypanosoma spp. parasitizing non-human hosts. The assemblies exhibit sizes consistent with previously sequenced trypanosomatid genomes, ranging from approximately 18 Mb for Obscuromonas modryi to 35 Mb for Crithidia brevicula and Zelonia costaricensis. Despite being the smallest, the genome of O. modryi has the highest content of repetitive elements, contributing nearly half of its total size. Conversely, the highest proportion of unique DNA is found in the genomes of Wallacemonas spp., with repeats accounting for less than 8% of the assembly length. The majority of examined species exhibit varying degrees of aneuploidy, with trisomy being the most frequently observed condition after disomy. CONCLUSIONS The genome of Obscuromonas modryi represents a very unusual, if not unique, example of evolution driven by two antidromous forces: i) increasing dependence on the host leading to genomic shrinkage and ii) expansion of repeats causing genome enlargement. The observed variation in somy within and between trypanosomatid genera suggests that these flagellates are largely predisposed to aneuploidy and, apparently, exploit it to gain a fitness advantage. High heterogeneity in the genome size, repeat content, and variation in chromosome copy numbers in the newly-sequenced species highlight the remarkable genome plasticity exhibited by trypanosomatid flagellates. These new genome assemblies are a robust foundation for future research on the genetic basis of life cycle changes and adaptation to different hosts in the family Trypanosomatidae.
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Affiliation(s)
- Amanda T S Albanaz
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00, Ostrava, Czech Republic
| | - Mark Carrington
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK
| | - Alexander O Frolov
- Zoological Institute of the Russian Academy of Sciences, 199034, St. Petersburg, Russia
| | - Anna I Ganyukova
- Zoological Institute of the Russian Academy of Sciences, 199034, St. Petersburg, Russia
| | - Evgeny S Gerasimov
- Faculty of Biology, M. V. Lomonosov Moscow State University, 119991, Moscow, Russia
- Martsinovsky Institute of Medical Parasitology, Sechenov University, 119435, Moscow, Russia
| | - Alexei Y Kostygov
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00, Ostrava, Czech Republic
| | - Julius Lukeš
- Institute of Parasitology, Czech Academy of Sciences, 370 05, České Budějovice, Czech Republic
- Faculty of Sciences, University of South Bohemia, 370 05, České Budějovice, Czech Republic
| | - Marina N Malysheva
- Zoological Institute of the Russian Academy of Sciences, 199034, St. Petersburg, Russia
| | - Jan Votýpka
- Institute of Parasitology, Czech Academy of Sciences, 370 05, České Budějovice, Czech Republic
- Department of Parasitology, Faculty of Science, Charles University, 128 44, Prague, Czech Republic
| | - Alexandra Zakharova
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00, Ostrava, Czech Republic
| | - Kristína Záhonová
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00, Ostrava, Czech Republic
- Institute of Parasitology, Czech Academy of Sciences, 370 05, České Budějovice, Czech Republic
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, 252 50, Vestec, Czech Republic
- Division of Infectious Diseases, Department of Medicine, University of Alberta, Edmonton, T6G 2G3, Canada
| | - Sara L Zimmer
- Duluth Campus, University of Minnesota Medical School, Duluth, MN, 55812, USA
| | - Vyacheslav Yurchenko
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00, Ostrava, Czech Republic.
| | - Anzhelika Butenko
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00, Ostrava, Czech Republic.
- Institute of Parasitology, Czech Academy of Sciences, 370 05, České Budějovice, Czech Republic.
- Faculty of Sciences, University of South Bohemia, 370 05, České Budějovice, Czech Republic.
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5
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Wacker T, Helmstetter N, Wilson D, Fisher MC, Studholme DJ, Farrer RA. Two-speed genome evolution drives pathogenicity in fungal pathogens of animals. Proc Natl Acad Sci U S A 2023; 120:e2212633120. [PMID: 36595674 PMCID: PMC9926174 DOI: 10.1073/pnas.2212633120] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 11/14/2022] [Indexed: 01/05/2023] Open
Abstract
The origins and evolution of virulence in amphibian-infecting chytrids Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal) are largely unknown. Here, we use deep nanopore sequencing of Bsal and comparative genomics against 21 high-quality genome assemblies that span the fungal Chytridiomycota. We discover that Bsal has the most repeat-rich genome of the Chytridiomycota, comprising 40.9% repetitive elements; this genome has expanded to more than 3× the length of its conspecific Bd, with autonomous and fully functional LTR/Gypsy elements contributing significantly to the expansion. The M36 metalloprotease virulence factors are highly expanded (n = 177) in Bsal, most of which (53%) are flanked by transposable elements, suggesting they have a repeat-associated expansion. We find enrichment upstream of M36 metalloprotease genes of three novel repeat families belonging to the repeat superfamily of LINEs that are implicated with gene copy number variations. Additionally, Bsal has a highly compartmentalized genome architecture, with virulence factors enriched in gene-sparse/repeat-rich compartments, while core conserved genes are enriched in gene-rich/repeat-poor compartments. Genes upregulated during infection are primarily found in the gene-sparse/repeat-rich compartment in both Bd and Bsal. Furthermore, genes with signatures of positive selection in Bd are enriched in repeat-rich regions, suggesting these regions are a cradle for the evolution of chytrid pathogenicity. These are the hallmarks of two-speed genome evolution, and this study provides evidence of two-speed genomes in an animal pathogen, shedding light on the evolution of fungal pathogens of vertebrates driving global declines and extinctions.
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Affiliation(s)
- Theresa Wacker
- Medical Research Council Centre for Medical Mycology at the University of Exeter, ExeterEX4 4QD, United Kingdom
| | - Nicolas Helmstetter
- Medical Research Council Centre for Medical Mycology at the University of Exeter, ExeterEX4 4QD, United Kingdom
| | - Duncan Wilson
- Medical Research Council Centre for Medical Mycology at the University of Exeter, ExeterEX4 4QD, United Kingdom
| | - Matthew C. Fisher
- Medical Research Council (MRC) Centre for Global Infectious Disease Analysis, Imperial College London, LondonW12 0BZ, United Kingdom
| | - David J. Studholme
- Department of Biosciences, University of Exeter, ExeterEX4 4QD, United Kingdom
| | - Rhys A. Farrer
- Medical Research Council Centre for Medical Mycology at the University of Exeter, ExeterEX4 4QD, United Kingdom
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6
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Byrne AQ, Waddle AW, Saenz V, Ohmer M, Jaeger JR, Richards-Zawacki CL, Voyles J, Rosenblum EB. Host species is linked to pathogen genotype for the amphibian chytrid fungus (Batrachochytrium dendrobatidis). PLoS One 2022; 17:e0261047. [PMID: 35286323 PMCID: PMC8920232 DOI: 10.1371/journal.pone.0261047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 03/01/2022] [Indexed: 11/21/2022] Open
Abstract
Host-pathogen specificity can arise from certain selective environments mediated by both the host and pathogen. Therefore, understanding the degree to which host species identity is correlated with pathogen genotype can help reveal historical host-pathogen dynamics. One animal disease of particular concern is chytridiomycosis, typically caused by the global panzootic lineage of the amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd), termed Bd-GPL. This pathogen lineage has caused devastating declines in amphibian communities around the world. However, the site of origin for the common ancestor of modern Bd-GPL and the fine-scale transmission dynamics of this lineage have remained a mystery. This is especially the case in North America where Bd-GPL is widespread, but disease outbreaks occur sporadically. Herein, we use Bd genetic data collected throughout the United States from amphibian skin swabs and cultured isolate samples to investigate Bd genetic patterns. We highlight two case studies in Pennsylvania and Nevada where Bd-GPL genotypes are strongly correlated with host species identity. Specifically, in some localities bullfrogs (Rana catesbeiana) are infected with Bd-GPL lineages that are distinct from those infecting other sympatric amphibian species. Overall, we reveal a previously unknown association of Bd genotype with host species and identify the eastern United States as a Bd diversity hotspot and potential site of origin for Bd-GPL.
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Affiliation(s)
- Allison Q. Byrne
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, California, United States of America
- * E-mail:
| | - Anthony W. Waddle
- One Health Research Group, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Victoria, Australia
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, Nevada, United States of America
| | - Veronica Saenz
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Michel Ohmer
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Biology, University of Mississippi, Oxford, Mississippi, United States of America
| | - Jef R. Jaeger
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, Nevada, United States of America
| | - Corinne L. Richards-Zawacki
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Jamie Voyles
- Department of Biology, University of Nevada Reno, Reno, Nevada, United States of America
| | - Erica Bree Rosenblum
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, California, United States of America
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7
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Farrer RA. HaplotypeTools: a toolkit for accurately identifying recombination and recombinant genotypes. BMC Bioinformatics 2021; 22:560. [PMID: 34809571 PMCID: PMC8607637 DOI: 10.1186/s12859-021-04473-1] [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: 07/20/2021] [Accepted: 11/10/2021] [Indexed: 11/17/2022] Open
Abstract
Background Identifying haplotypes is central to sequence analysis in diploid or polyploid genomes. Despite this, there remains a lack of research and tools designed for physical phasing and its downstream analysis. Results HaplotypeTools is a new toolset to phase variant sites using VCF and BAM files and to analyse phased VCFs. Phasing is achieved via the identification of reads overlapping ≥ 2 heterozygous positions and then extended by additional reads, a process that can be parallelized across a computer cluster. HaplotypeTools includes various utility scripts for downstream analysis including crossover detection and phylogenetic placement of haplotypes to other lineages or species. HaplotypeTools was assessed for accuracy against WhatsHap using simulated short and long reads, demonstrating higher accuracy, albeit with reduced haplotype length. HaplotypeTools was also tested on real Illumina data to determine the ancestry of hybrid fungal isolate Batrachochytrium dendrobatidis (Bd) SA-EC3, finding 80% of haplotypes across the genome phylogenetically cluster with parental lineages BdGPL (39%) and BdCAPE (41%), indicating those are the parental lineages. Finally, ~ 99% of phasing was conserved between overlapping phase groups between SA-EC3 and either parental lineage, indicating mitotic gene conversion/parasexuality as the mechanism of recombination for this hybrid isolate. HaplotypeTools is open source and freely available from https://github.com/rhysf/HaplotypeTools under the MIT License. Conclusions HaplotypeTools is a powerful resource for analyzing hybrid or recombinant diploid or polyploid genomes and identifying parental ancestry for sub-genomic regions.
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Affiliation(s)
- Rhys A Farrer
- Medical Research Council Centre for Medical Mycology at the University of Exeter, Exeter, UK.
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8
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Wang Y, Verbrugghe E, Meuris L, Chiers K, Kelly M, Strubbe D, Callewaert N, Pasmans F, Martel A. Epidermal galactose spurs chytrid virulence and predicts amphibian colonization. Nat Commun 2021; 12:5788. [PMID: 34608163 PMCID: PMC8490390 DOI: 10.1038/s41467-021-26127-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 09/09/2021] [Indexed: 02/08/2023] Open
Abstract
The chytrid fungal pathogens Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans cause the skin disease chytridiomycosis in amphibians, which is driving a substantial proportion of an entire vertebrate class to extinction. Mitigation of its impact is largely unsuccessful and requires a thorough understanding of the mechanisms underpinning the disease ecology. By identifying skin factors that mediate key events during the early interaction with B. salamandrivorans zoospores, we discovered a marker for host colonization. Amphibian skin associated beta-galactose mediated fungal chemotaxis and adhesion to the skin and initiated a virulent fungal response. Fungal colonization correlated with the skin glycosylation pattern, with cutaneous galactose content effectively predicting variation in host susceptibility to fungal colonization between amphibian species. Ontogenetic galactose patterns correlated with low level and asymptomatic infections in salamander larvae that were carried over through metamorphosis, resulting in juvenile mortality. Pronounced variation of galactose content within some, but not all species, may promote the selection for more colonization resistant host lineages, opening new avenues for disease mitigation.
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Affiliation(s)
- Yu Wang
- grid.5342.00000 0001 2069 7798Wildlife Health Ghent, Department of Pathology, Bacteriology and Poultry Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Elin Verbrugghe
- grid.5342.00000 0001 2069 7798Wildlife Health Ghent, Department of Pathology, Bacteriology and Poultry Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Leander Meuris
- grid.5342.00000 0001 2069 7798Center for Medical Biotechnology, Department of Biochemistry and Microbiology, VIB-Ghent University, Zwijnaarde, Belgium
| | - Koen Chiers
- grid.5342.00000 0001 2069 7798Department of Pathology, Bacteriology and Poultry Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Moira Kelly
- grid.5342.00000 0001 2069 7798Wildlife Health Ghent, Department of Pathology, Bacteriology and Poultry Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Diederik Strubbe
- grid.5342.00000 0001 2069 7798Terrestrial Ecology Unit, Department of Biology, Faculty of Sciences, Ghent University, Ghent, Belgium
| | - Nico Callewaert
- grid.5342.00000 0001 2069 7798Center for Medical Biotechnology, Department of Biochemistry and Microbiology, VIB-Ghent University, Zwijnaarde, Belgium
| | - Frank Pasmans
- grid.5342.00000 0001 2069 7798Wildlife Health Ghent, Department of Pathology, Bacteriology and Poultry Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - An Martel
- grid.5342.00000 0001 2069 7798Wildlife Health Ghent, Department of Pathology, Bacteriology and Poultry Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
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9
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Early-diverging fungal phyla: taxonomy, species concept, ecology, distribution, anthropogenic impact, and novel phylogenetic proposals. FUNGAL DIVERS 2021; 109:59-98. [PMID: 34608378 PMCID: PMC8480134 DOI: 10.1007/s13225-021-00480-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Accepted: 07/19/2021] [Indexed: 01/02/2023]
Abstract
The increasing number of new fungal species described from all over the world along with the use of genetics to define taxa, has dramatically changed the classification system of early-diverging fungi over the past several decades. The number of phyla established for non-Dikarya fungi has increased from 2 to 17. However, to date, both the classification and phylogeny of the basal fungi are still unresolved. In this article, we review the recent taxonomy of the basal fungi and re-evaluate the relationships among early-diverging lineages of fungal phyla. We also provide information on the ecology and distribution in Mucoromycota and highlight the impact of chytrids on amphibian populations. Species concepts in Chytridiomycota, Aphelidiomycota, Rozellomycota, Neocallimastigomycota are discussed in this paper. To preserve the current application of the genus Nephridiophaga (Chytridiomycota: Nephridiophagales), a new type species, Nephridiophaga blattellae, is proposed.
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10
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Nielsen KN, Salgado JFM, Natsopoulou ME, Kristensen T, Stajich JE, De Fine Licht HH. Diploidy within a Haploid Genus of Entomopathogenic Fungi. Genome Biol Evol 2021; 13:evab158. [PMID: 34247231 PMCID: PMC8325562 DOI: 10.1093/gbe/evab158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/02/2021] [Indexed: 12/28/2022] Open
Abstract
Fungi in the genus Metarhizium are soil-borne plant-root endophytes and rhizosphere colonizers, but also potent insect pathogens with highly variable host ranges. These ascomycete fungi are predominantly asexually reproducing and ancestrally haploid, but two independent origins of persistent diploidy within the Coleoptera-infecting Metarhizium majus species complex are known and has been attributed to incomplete chromosomal segregation following meiosis during the sexual cycle. There is also evidence for infrequent sexual cycles in the locust-specific pathogenic fungus Metarhizium acridum (Hypocreales: Clavicipitaceae), which is an important entomopathogenic biocontrol agent used for the control of grasshoppers in agricultural systems as an alternative to chemical control. Here, we show that the genome of the M. acridum isolate ARSEF 324, which is formulated and commercially utilized is functionally diploid. We used single-molecule real-time sequencing technology to complete a high-quality assembly of ARSEF 324. K-mer frequencies, intragenomic collinearity between contigs and single nucleotide variant read depths across the genome revealed the first incidence of diploidy described within the species M. acridum. The haploid assembly of 44.7 Mb consisted of 20.8% repetitive elements, which is the highest proportion described of any Metarhizium species. The long-read diploid genome assembly sheds light on past research on this strain, such as unusual high UVB tolerance. The data presented here could fuel future investigation into the fitness landscape of fungi with infrequent sexual reproduction and aberrant ploidy levels, not least in the context of biocontrol agents.
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Affiliation(s)
- Knud Nor Nielsen
- Section for Organismal Biology, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - João Felipe Moreira Salgado
- Department of Microbiology and Plant Pathology, University of California Riverside, California, USA
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Brazil
| | - Myrsini Eirini Natsopoulou
- Section for Organismal Biology, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Thea Kristensen
- Section for Organismal Biology, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Jason E Stajich
- Department of Microbiology and Plant Pathology, University of California Riverside, California, USA
| | - Henrik H De Fine Licht
- Section for Organismal Biology, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Denmark
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11
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Rothstein AP, Byrne AQ, Knapp RA, Briggs CJ, Voyles J, Richards-Zawacki CL, Rosenblum EB. Divergent regional evolutionary histories of a devastating global amphibian pathogen. Proc Biol Sci 2021; 288:20210782. [PMID: 34157877 PMCID: PMC8220259 DOI: 10.1098/rspb.2021.0782] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Emerging infectious diseases are a pressing threat to global biological diversity. Increased incidence and severity of novel pathogens underscores the need for methodological advances to understand pathogen emergence and spread. Here, we use genetic epidemiology to test, and challenge, key hypotheses about a devastating zoonotic disease impacting amphibians globally. Using an amplicon-based sequencing method and non-invasive samples we retrospectively explore the history of the fungal pathogen Batrachochytrium dendrobatidis (Bd) in two emblematic amphibian systems: the Sierra Nevada of California and Central Panama. The hypothesis in both regions is the hypervirulent Global Panzootic Lineage of Bd (BdGPL) was recently introduced and spread rapidly in a wave-like pattern. Our data challenge this hypothesis by demonstrating similar epizootic signatures can have radically different underlying evolutionary histories. In Central Panama, our genetic data confirm a recent and rapid pathogen spread. However, BdGPL in the Sierra Nevada has remarkable spatial structuring, high genetic diversity and a relatively older history inferred from time-dated phylogenies. Thus, this deadly pathogen lineage may have a longer history in some regions than assumed, providing insights into its origin and spread. Overall, our results highlight the importance of integrating observed wildlife die-offs with genetic data to more accurately reconstruct pathogen outbreaks.
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Affiliation(s)
- Andrew P Rothstein
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, USA.,Museum of Vertebrate Zoology, University of California Berkeley, Berkeley, CA, USA
| | - Allison Q Byrne
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, USA.,Museum of Vertebrate Zoology, University of California Berkeley, Berkeley, CA, USA.,Center for Conservation Genomics, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, DC, USA
| | - Roland A Knapp
- Sierra Nevada Aquatic Research Laboratory, University of California, Mammoth Lakes, CA, USA.,Earth Research Institute, University of California, Santa Barbara, CA, USA
| | - Cheryl J Briggs
- Earth Research Institute, University of California, Santa Barbara, CA, USA.,Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA, USA
| | - Jamie Voyles
- Department of Biology, University of Nevada, Reno, NV, USA
| | | | - Erica Bree Rosenblum
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, USA.,Museum of Vertebrate Zoology, University of California Berkeley, Berkeley, CA, USA
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12
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Medina D, Greenspan SE, Carvalho T, Becker CG, Toledo LF. Co-infecting pathogen lineages have additive effects on host bacterial communities. FEMS Microbiol Ecol 2021; 97:6134751. [PMID: 33580951 DOI: 10.1093/femsec/fiab030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 02/11/2021] [Indexed: 01/08/2023] Open
Abstract
Amphibian skin bacteria may confer protection against the fungus Batrachochytrium dendrobatidis (Bd), but responses of skin bacteria to different Bd lineages are poorly understood. The global panzootic lineage (Bd-GPL) has caused amphibian declines and extinctions globally. However, other lineages are enzootic (Bd-Asia-2/Brazil). Increased contact rates between Bd-GPL and enzootic lineages via globalization pose unknown consequences for host-microbiome-pathogen dynamics. We conducted a laboratory experiment and used 16S rRNA amplicon-sequencing to assess: (i) whether two lineages (Bd-Asia-2/Brazil and Bd-GPL) and their recombinant, in single and mixed infections, differentially affect amphibian skin bacteria; (ii) and the changes associated with the transition to laboratory conditions. We determined no clear differences in bacterial diversity among Bd treatments, despite differences in infection intensity. However, we observed an additive effect of mixed infections on bacterial alpha diversity and a potentially antagonistic interaction between Bd genotypes. Additionally, observed changes in community composition suggest a higher ability of Bd-GPL to alter skin bacteria. Lastly, we observed a drastic reduction in bacterial diversity and a change in community structure in laboratory conditions. We provide evidence for complex interactions between Bd genotypes and amphibian skin bacteria during coinfections, and expand on the implications of experimental conditions in ecological studies.
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Affiliation(s)
- Daniel Medina
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Instituto de Biologia, Universidade Estadual de Campinas, R. Monteiro Lobato, 255 - CEP 13083-862, Campinas, São Paulo, Brazil.,Sistema Nacional de Investigación, SENACYT, Building 205, City of Knowledge, Clayton, Panama, Republic of Panama
| | - Sasha E Greenspan
- Department of Biological Sciences, The University of Alabama, 1339 Science and Engineering Complex, Tuscaloosa 35487, Alabama, USA
| | - Tamilie Carvalho
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Instituto de Biologia, Universidade Estadual de Campinas, R. Monteiro Lobato, 255 - CEP 13083-862, Campinas, São Paulo, Brazil
| | - C Guilherme Becker
- Department of Biological Sciences, The University of Alabama, 1339 Science and Engineering Complex, Tuscaloosa 35487, Alabama, USA
| | - Luís Felipe Toledo
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Instituto de Biologia, Universidade Estadual de Campinas, R. Monteiro Lobato, 255 - CEP 13083-862, Campinas, São Paulo, Brazil
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13
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Gerstein AC, Sharp NP. The population genetics of ploidy change in unicellular fungi. FEMS Microbiol Rev 2021; 45:6121427. [PMID: 33503232 DOI: 10.1093/femsre/fuab006] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 01/14/2021] [Indexed: 12/23/2022] Open
Abstract
Changes in ploidy are a significant type of genetic variation, describing the number of chromosome sets per cell. Ploidy evolves in natural populations, clinical populations, and lab experiments, particularly in fungi. Despite a long history of theoretical work on this topic, predicting how ploidy will evolve has proven difficult, as it is often unclear why one ploidy state outperforms another. Here, we review what is known about contemporary ploidy evolution in diverse fungal species through the lens of population genetics. As with typical genetic variants, ploidy evolution depends on the rate that new ploidy states arise by mutation, natural selection on alternative ploidy states, and random genetic drift. However, ploidy variation also has unique impacts on evolution, with the potential to alter chromosomal stability, the rate and patterns of point mutation, and the nature of selection on all loci in the genome. We discuss how ploidy evolution depends on these general and unique factors and highlight areas where additional experimental evidence is required to comprehensively explain the ploidy transitions observed in the field and the lab.
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Affiliation(s)
- Aleeza C Gerstein
- Dept. of Microbiology, Dept. of Statistics, University of Manitoba Canada
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14
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Vogel G, Gore MA, Smart CD. Genome-Wide Association Study in New York Phytophthora capsici Isolates Reveals Loci Involved in Mating Type and Mefenoxam Sensitivity. PHYTOPATHOLOGY 2021; 111:204-216. [PMID: 32539639 DOI: 10.1094/phyto-04-20-0112-fi] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Phytophthora capsici is a soilborne oomycete plant pathogen that causes severe vegetable crop losses in New York (NY) state and worldwide. This pathogen is difficult to manage, in part due to its production of long-lasting sexual spores and its tendency to quickly evolve fungicide resistance. We single nucleotide polymorphism (SNP) genotyped 252 P. capsici isolates, predominantly from NY, in order to conduct a genome-wide association study for mating type and mefenoxam sensitivity. The population structure and extent of chromosomal copy number variation in this collection of isolates were also characterized. Population structure analyses showed isolates largely clustered by the field site where they were collected, with values of FST between pairs of fields ranging from 0.10 to 0.31. Thirty-three isolates were putative aneuploids, demonstrating evidence for having up to four linkage groups present in more than two copies, and an additional two isolates appeared to be genome-wide triploids. Mating type was mapped to a region on scaffold 4, consistent with previous findings, and mefenoxam sensitivity was associated with several SNP markers at a novel locus on scaffold 62. We identified several candidate genes for mefenoxam sensitivity, including a homolog of yeast ribosome synthesis factor Rrp5, but failed to locate near the scaffold 62 locus any subunits of RNA polymerase I, the hypothesized target site of phenylamide fungicides in oomycetes. This work expands our knowledge of the population biology of P. capsici and provides a foundation for functional validation of candidate genes associated with epidemiologically important phenotypes.
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Affiliation(s)
- Gregory Vogel
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Geneva, NY 14456
| | - Michael A Gore
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853
| | - Christine D Smart
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Geneva, NY 14456
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15
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Sieber N, Hartikainen H, Vorburger C. Validation of an eDNA-based method for the detection of wildlife pathogens in water. DISEASES OF AQUATIC ORGANISMS 2020; 141:171-184. [PMID: 33089822 DOI: 10.3354/dao03524] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Monitoring the occurrence and density of parasites and pathogens can identify high infection-risk areas and facilitates disease control and eradication measures. Environmental DNA (eDNA) techniques are increasingly used for pathogen detection due to their relative ease of application. Since many factors affect the reliability and efficacy of eDNA-based detection, rigorous validation and assessment of method limitations is a crucial first step. We evaluated an eDNA detection method using in situ filtration of large-volume water samples, developed to detect and quantify aquatic wildlife parasites by quantitative PCR (qPCR). We assessed method reliability using Batrachochytrium dendrobatidis, a pathogenic fungus of amphibians and the myxozoan Tetracapsuloides bryosalmonae, causative agent of salmonid proliferative kidney disease, in a controlled experimental setup. Different amounts of parasite spores were added to tanks containing either clean tap water or water from a semi-natural mesocosm community. Overall detection rates were higher than 80%, but detection was not consistent among replicate samples. Within-tank variation in detection emphasises the need for increased site-level replication when dealing with parasites and pathogens. Estimated parasite DNA concentrations in water samples were highly variable, and a significant increase with higher spore concentrations was observed only for B. dendrobatidis. Despite evidence for PCR inhibition in DNA extractions from mesocosm water samples, the type of water did not affect detection rates significantly. Direct spiking controls revealed that the filtration step reduced detection sensitivity. Our study identifies sensitive quantification and sufficient replication as major remaining challenges for the eDNA-based methods for detection of parasites in water.
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Affiliation(s)
- Natalie Sieber
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
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16
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Naranjo‐Ortiz MA, Gabaldón T. Fungal evolution: cellular, genomic and metabolic complexity. Biol Rev Camb Philos Soc 2020; 95:1198-1232. [PMID: 32301582 PMCID: PMC7539958 DOI: 10.1111/brv.12605] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 03/31/2020] [Accepted: 04/02/2020] [Indexed: 12/13/2022]
Abstract
The question of how phenotypic and genomic complexity are inter-related and how they are shaped through evolution is a central question in biology that historically has been approached from the perspective of animals and plants. In recent years, however, fungi have emerged as a promising alternative system to address such questions. Key to their ecological success, fungi present a broad and diverse range of phenotypic traits. Fungal cells can adopt many different shapes, often within a single species, providing them with great adaptive potential. Fungal cellular organizations span from unicellular forms to complex, macroscopic multicellularity, with multiple transitions to higher or lower levels of cellular complexity occurring throughout the evolutionary history of fungi. Similarly, fungal genomes are very diverse in their architecture. Deep changes in genome organization can occur very quickly, and these phenomena are known to mediate rapid adaptations to environmental changes. Finally, the biochemical complexity of fungi is huge, particularly with regard to their secondary metabolites, chemical products that mediate many aspects of fungal biology, including ecological interactions. Herein, we explore how the interplay of these cellular, genomic and metabolic traits mediates the emergence of complex phenotypes, and how this complexity is shaped throughout the evolutionary history of Fungi.
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Affiliation(s)
- Miguel A. Naranjo‐Ortiz
- Bioinformatics and Genomics Programme, Centre for Genomic Regulation (CRG)The Barcelona Institute of Science and TechnologyDr. Aiguader 88, Barcelona08003Spain
| | - Toni Gabaldón
- Bioinformatics and Genomics Programme, Centre for Genomic Regulation (CRG)The Barcelona Institute of Science and TechnologyDr. Aiguader 88, Barcelona08003Spain
- Department of Experimental Sciences, Universitat Pompeu Fabra (UPF)Dr. Aiguader 88, 08003BarcelonaSpain
- ICREAPg. Lluís Companys 23, 08010BarcelonaSpain
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17
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Integrated Analysis of Gene Expression, SNP, InDel, and CNV Identifies Candidate Avirulence Genes in Australian Isolates of the Wheat Leaf Rust Pathogen Puccinia triticina. Genes (Basel) 2020; 11:genes11091107. [PMID: 32967372 PMCID: PMC7564353 DOI: 10.3390/genes11091107] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 09/18/2020] [Indexed: 11/17/2022] Open
Abstract
The leaf rust pathogen, Puccinia triticina (Pt), threatens global wheat production. The deployment of leaf rust (Lr) resistance (R) genes in wheat varieties is often followed by the development of matching virulence in Pt due to presumed changes in avirulence (Avr) genes in Pt. Identifying such Avr genes is a crucial step to understand the mechanisms of wheat-rust interactions. This study is the first to develop and apply an integrated framework of gene expression, single nucleotide polymorphism (SNP), insertion/deletion (InDel), and copy number variation (CNV) analysis in a rust fungus and identify candidate avirulence genes. Using a long-read based de novo genome assembly of an isolate of Pt ('Pt104') as the reference, whole-genome resequencing data of 12 Pt pathotypes derived from three lineages Pt104, Pt53, and Pt76 were analyzed. Candidate avirulence genes were identified by correlating virulence profiles with small variants (SNP and InDel) and CNV, and RNA-seq data of an additional three Pt isolates to validate expression of genes encoding secreted proteins (SPs). Out of the annotated 29,043 genes, 2392 genes were selected as SP genes with detectable expression levels. Small variant comparisons between the isolates identified 27-40 candidates and CNV analysis identified 14-31 candidates for each Avr gene, which when combined, yielded the final 40, 64, and 69 candidates for AvrLr1, AvrLr15, and AvrLr24, respectively. Taken together, our results will facilitate future work on experimental validation and cloning of Avr genes. In addition, the integrated framework of data analysis that we have developed and reported provides a more comprehensive approach for Avr gene mining than is currently available.
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18
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Burrowes PA, James TY, Jenkinson TS, De la Riva I. Genetic analysis of post-epizootic amphibian chytrid strains in Bolivia: Adding a piece to the puzzle. Transbound Emerg Dis 2020; 67:2163-2171. [PMID: 32277592 DOI: 10.1111/tbed.13568] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 02/11/2020] [Accepted: 03/14/2020] [Indexed: 12/26/2022]
Abstract
The evolutionary history and dispersal pattern of Batrachochytrium dendrobatidis (Bd), an emergent fungal pathogen responsible for the decline and extinctions of many species of amphibians worldwide, is still not well understood. In South America, the tropical Andes are known as an important site for amphibian diversification, but also for being a place where hosts are at greater risk of chytridiomycosis. In an attempt to understand the history and the geographic pattern of Bd-associated amphibian declines in Bolivia, we isolated Bd from hosts at two locations that differ in their chronology of Bd prevalence and host survival outcome, the cloud forests of the Amazonian slopes of the Andes and Lake Titicaca in the altiplano. We genotyped Bd from both locations and sequenced the genome from the cloud forest isolate and then compared them to reference sequences of other Bd strains across the world. We found that the Bolivian chytrid isolates were nearly genotypically identical and that they belong to the global panzootic lineage (Bd-GPL). The Bolivian Bd strain grouped with other tropical New World strains but was closest to those from the Brazilian Atlantic Forest. Our results extend the presence of Bd-GPL to the central Andes in South America and report this hypervirulent strain at Lago Titicaca, where Bd has been detected since 1863, without evidence of amphibian declines. These findings suggest a more complex evolutionary history for this pathogen in Bolivia and may point to the existence of an old lineage of Bd that has since been extirpated following the arrival of the panzootic Bd-GPL or that the timing of Bd-GPL emergence is earlier than generally acknowledged.
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Affiliation(s)
| | - Timothy Y James
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Thomas S Jenkinson
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, USA
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19
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McDonald CA, Longo AV, Lips KR, Zamudio KR. Incapacitating effects of fungal coinfection in a novel pathogen system. Mol Ecol 2020; 29:3173-3186. [PMID: 32310322 DOI: 10.1111/mec.15452] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 03/16/2020] [Accepted: 04/08/2020] [Indexed: 12/20/2022]
Abstract
As globalization lowers geographic barriers to movement, coinfection with novel and enzootic pathogens is increasingly likely. Novel and enzootic pathogens can interact synergistically or antagonistically, leading to increased or decreased disease severity. Here we examine host immune responses to coinfection with two closely related fungal pathogens: Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal). Both pathogens have had detrimental effects on amphibian populations, with Bd now largely enzootic, while Bsal is currently spreading and causing epizootics. Recent experimental work revealed that newts coinfected with Bd and Bsal had significantly higher mortality than those infected with either pathogen alone. Here we characterize host immunogenomic responses to chytrid coinfection relative to single infection. Across several classes of immune genes including pattern recognition receptors, cytokines, and MHC, coinfected host gene expression was weakly upregulated or comparable to that seen in single Bd infection, but significantly decreased when compared to Bsal infection. Combined with strong complement pathway downregulation and keratin upregulation, these results indicate that coinfection with Bd and Bsal compromises immune responses active against Bsal alone. As Bsal continues to invade naïve habitats where Bd is enzootic, coinfection will be increasingly common. If other Bd-susceptible species in the region have similar responses, interactions between the two pathogens could cause severe population and community-level declines.
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Affiliation(s)
- Cait A McDonald
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA
| | - Ana V Longo
- Department of Biology, University of Maryland, College Park, MD, USA
| | - Karen R Lips
- Department of Biology, University of Maryland, College Park, MD, USA
| | - Kelly R Zamudio
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA
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20
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Coelho C, Farrer RA. Pathogen and host genetics underpinning cryptococcal disease. ADVANCES IN GENETICS 2020; 105:1-66. [PMID: 32560785 DOI: 10.1016/bs.adgen.2020.02.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cryptococcosis is a severe fungal disease causing 220,000 cases of cryptococcal meningitis yearly. The etiological agents of cryptococcosis are taxonomically grouped into at least two species complexes belonging to the genus Cryptococcus. All of these yeasts are environmentally ubiquitous fungi (often found in soil, leaves and decaying wood, tree hollows, and associated with bird feces especially pigeon guano). Infection in a range of animals including humans begins following inhalation of spores or aerosolized yeasts. Recent advances provide fundamental insights into the factors from both the pathogen and its hosts which influence pathogenesis and disease. The complex interactions leading to disease in mammalian hosts have also updated from the availability of better genomic tools and datasets. In this review, we discuss recent genetic research on Cryptococcus, covering the epidemiology, ecology, and evolution of Cryptococcus pathogenic species. We also discuss the insights into the host immune response obtained from the latest genetic modified host models as well as insights from monogenic disorders in humans. Finally we highlight outstanding questions that can be answered in the near future using bioinformatics and genomic tools.
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Affiliation(s)
- Carolina Coelho
- Medical Research Council Centre for Medical Mycology at the University of Exeter, Exeter, United Kingdom
| | - Rhys A Farrer
- Medical Research Council Centre for Medical Mycology at the University of Exeter, Exeter, United Kingdom.
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21
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Wang L, Chen H, Li J, Shu H, Zhang X, Wang Y, Tyler BM, Dong S. Effector gene silencing mediated by histone methylation underpins host adaptation in an oomycete plant pathogen. Nucleic Acids Res 2020; 48:1790-1799. [PMID: 31819959 PMCID: PMC7039004 DOI: 10.1093/nar/gkz1160] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 11/23/2019] [Accepted: 11/29/2019] [Indexed: 12/21/2022] Open
Abstract
The relentless adaptability of pathogen populations is a major obstacle to effective disease control measures. Increasing evidence suggests that gene transcriptional polymorphisms are a strategy deployed by pathogens to evade host immunity. However, the underlying mechanisms of transcriptional plasticity remain largely elusive. Here we found that the soybean root rot pathogen Phytophthora sojae evades the soybean Resistance gene Rps1b through transcriptional polymorphisms in the effector gene Avr1b that occur in the absence of any sequence variation. Elevated levels of histone H3 Lysine27 tri-methylation (H3K27me3) were observed at the Avr1b locus in a naturally occurring Avr1b-silenced strain but not in an Avr1b-expressing strain, suggesting a correlation between this epigenetic modification and silencing of Avr1b. To genetically test this hypothesis, we edited the gene, PsSu(z)12, encoding a core subunit of the H3K27me3 methyltransferase complex by using CRISPR/Cas9, and obtained three deletion mutants. H3K27me3 depletion within the Avr1b genomic region correlated with impaired Avr1b gene silencing in these mutants. Importantly, these mutants lost the ability to evade immune recognition by soybeans carrying Rps1b. These data support a model in which pathogen effector transcriptional polymorphisms are associated with changes in chromatin epigenetic marks, highlighting epigenetic variation as a mechanism of pathogen adaptive plasticity.
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Affiliation(s)
- Liyuan Wang
- Department of Plant Pathology, Nanjing Agriculture University, Nanjing 210095, China
| | - Han Chen
- Department of Plant Pathology, Nanjing Agriculture University, Nanjing 210095, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China
| | - JiangJiang Li
- Department of Plant Pathology, Nanjing Agriculture University, Nanjing 210095, China
| | - Haidong Shu
- Department of Plant Pathology, Nanjing Agriculture University, Nanjing 210095, China
| | - Xiangxue Zhang
- Department of Plant Pathology, Nanjing Agriculture University, Nanjing 210095, China
| | - Yuanchao Wang
- Department of Plant Pathology, Nanjing Agriculture University, Nanjing 210095, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China
| | - Brett M Tyler
- Center for Genome Research and Biocomputing, and Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA
| | - Suomeng Dong
- Department of Plant Pathology, Nanjing Agriculture University, Nanjing 210095, China
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing 210095, China
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22
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Abstract
Discovering that chytrid fungi cause chytridiomycosis in amphibians represented a paradigm shift in our understanding of how emerging infectious diseases contribute to global patterns of biodiversity loss. In this Review we describe how the use of multidisciplinary biological approaches has been essential to pinpointing the origins of amphibian-parasitizing chytrid fungi, including Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans, as well as to timing their emergence, tracking their cycles of expansion and identifying the core mechanisms that underpin their pathogenicity. We discuss the development of the experimental methods and bioinformatics toolkits that have provided a fuller understanding of batrachochytrid biology and informed policy and control measures.
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23
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Harrison XA, Sewell T, Fisher M, Antwis RE. Designing Probiotic Therapies With Broad-Spectrum Activity Against a Wildlife Pathogen. Front Microbiol 2020; 10:3134. [PMID: 32038568 PMCID: PMC6987264 DOI: 10.3389/fmicb.2019.03134] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 12/26/2019] [Indexed: 11/24/2022] Open
Abstract
Host-associated microbes form an important component of immunity that protect against infection by pathogens. Treating wild individuals with these protective microbes, known as probiotics, can reduce rates of infection and disease in both wild and captive settings. However, the utility of probiotics for tackling wildlife disease requires that they offer consistent protection across the broad genomic variation of the pathogen that hosts can encounter in natural settings. Here we develop multi-isolate probiotic consortia with the aim of effecting broad-spectrum inhibition of growth of the lethal amphibian pathogen Batrachochytrium dendrobatidis (Bd) when tested against nine Bd isolates from two distinct lineages. Though we achieved strong growth inhibition between 70 and 100% for seven Bd isolates, two isolates appeared consistently resistant to inhibition, irrespective of probiotic strategy employed. We found no evidence that genomic relatedness of the chytrid predicted similarity of inhibition scores, nor that increasing the genetic diversity of the bacterial consortia could offer stronger inhibition of pathogen growth, even for the two resistant isolates. Our findings have important consequences for the application of probiotics to mitigate wildlife diseases in the face of extensive pathogen genomic variation.
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Affiliation(s)
- Xavier A Harrison
- Institute of Zoology, Zoological Society of London, London, United Kingdom.,Centre for Ecology and Conservation, University of Exeter, Penryn, United Kingdom
| | - Thomas Sewell
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom
| | - Matthew Fisher
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom
| | - Rachael E Antwis
- School of Science, Engineering and Environment, University of Salford, Salford, United Kingdom
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24
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Hybridization Facilitates Adaptive Evolution in Two Major Fungal Pathogens. Genes (Basel) 2020; 11:genes11010101. [PMID: 31963231 PMCID: PMC7017293 DOI: 10.3390/genes11010101] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 01/02/2020] [Accepted: 01/14/2020] [Indexed: 01/13/2023] Open
Abstract
Hybridization is increasingly recognized as an important force impacting adaptation and evolution in many lineages of fungi. During hybridization, divergent genomes and alleles are brought together into the same cell, potentiating adaptation by increasing genomic plasticity. Here, we review hybridization in fungi by focusing on two fungal pathogens of animals. Hybridization is common between the basidiomycete yeast species Cryptococcus neoformans × Cryptococcus deneoformans, and hybrid genotypes are frequently found in both environmental and clinical settings. The two species show 10-15% nucleotide divergence at the genome level, and their hybrids are highly heterozygous. Though largely sterile and unable to mate, these hybrids can propagate asexually and generate diverse genotypes by nondisjunction, aberrant meiosis, mitotic recombination, and gene conversion. Under stress conditions, the rate of such genetic changes can increase, leading to rapid adaptation. Conversely, in hybrids formed between lineages of the chytridiomycete frog pathogen Batrachochytrium dendrobatidis (Bd), the parental genotypes are considerably less diverged (0.2% divergent). Bd hybrids are formed from crosses between lineages that rarely undergo sex. A common theme in both species is that hybrids show genome plasticity via aneuploidy or loss of heterozygosity and leverage these mechanisms as a rapid way to generate genotypic/phenotypic diversity. Some hybrids show greater fitness and survival in both virulence and virulence-associated phenotypes than parental lineages under certain conditions. These studies showcase how experimentation in model species such as Cryptococcus can be a powerful tool in elucidating the genotypic and phenotypic consequences of hybridization.
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25
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McDonald CA, Ellison AR, Toledo LF, James TY, Zamudio KR. Gene expression varies within and between enzootic and epizootic lineages of Batrachochytrium dendrobatidis (Bd) in the Americas. Fungal Biol 2019; 124:34-43. [PMID: 31892375 DOI: 10.1016/j.funbio.2019.10.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 07/29/2019] [Accepted: 10/21/2019] [Indexed: 12/16/2022]
Abstract
While much research focus is paid to hypervirulent fungal lineages during emerging infectious disease outbreaks, examining enzootic pathogen isolates can be equally fruitful in delineating infection dynamics and determining pathogenesis. The fungal pathogen of amphibians, Batrachochytrium dendrobatidis (Bd), exhibits markedly different patterns of disease in natural populations, where it has caused massive amphibian declines in some regions, yet persists enzootically in others. Here we compare in vitro gene expression profiles of a panel of Bd isolates representing both the enzootic Bd-Brazil lineage, and the more recently diverged, panzootic lineage, Bd-GPL. We document significantly different lineage-specific and intralineage gene expression patterns, with Bd-Brazil upregulating genes with aspartic-type peptidase activity, and Bd-GPL upregulating CBM18 chitin-binding genes, among others. We also find pronounced intralineage variation in membrane integrity and transmembrane transport ability within our Bd-GPL isolates. Finally, we highlight unexpectedly divergent expression profiles in sympatric panzootic isolates, underscoring microgeographic functional variation in a largely clonal lineage. This variation in gene expression likely plays an important role in the relative pathogenesis and host range of Bd-Brazil and Bd-GPL isolates. Together, our results demonstrate that functional genomics approaches can provide information relevant to studies of virulence evolution within the Bd clade.
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Affiliation(s)
- C A McDonald
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14850, USA.
| | - A R Ellison
- School of Natural Sciences, Bangor University, Bangor LL57 2UW, UK
| | - L F Toledo
- Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil
| | - T Y James
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - K R Zamudio
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14850, USA
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Fu M, Waldman B. Ancestral chytrid pathogen remains hypervirulent following its long coevolution with amphibian hosts. Proc Biol Sci 2019; 286:20190833. [PMID: 31161901 DOI: 10.1098/rspb.2019.0833] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Many amphibian species around the world, except in Asia, suffer morbidity and mortality when infected by the emerging infectious pathogen Batrachochytrium dendrobatidis (Bd). A lineage of the amphibian chytrid fungus isolated from South Korean amphibians (BdAsia-1) is evolutionarily basal to recombinant global pandemic lineages (BdGPL) associated with worldwide amphibian population declines. In Asia, the Bd pathogen and its amphibian hosts have coevolved over 100 years or more. Thus, resilience of Asian amphibian populations to infection might result from attenuated virulence of endemic Bd lineages, evolved immunity to the pathogen or both. We compared susceptibilities of an Australasian amphibian, Litoria caerulea, known to lack resistance to BdGPL, with those of three Korean species, Bufo gargarizans, Bombina orientalis and Hyla japonica, after inoculation with BdAsia-1, BdGPL or a blank solution. Subjects became infected in all experimental treatments but Korean species rapidly cleared themselves of infection, regardless of Bd lineage. They survived with no apparent secondary effects. By contrast, L. caerulea, after infection by either BdAsia-1 or BdGPL, suffered deteriorating body condition and carried progressively higher Bd loads over time. Subsequently, most subjects died. Comparing their effects on L. caerulea, BdAsia-1 induced more rapid disease progression than BdGPL. The results suggest that genomic recombination with other lineages was not necessary for the ancestral Bd lineage to evolve hypervirulence over its long period of coevolution with amphibian hosts. The pathogen's virulence may have driven strong selection for immune responses in endemic Asian amphibian host species.
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Affiliation(s)
- Minjie Fu
- 1 Laboratory of Behavioral and Population Ecology, School of Biological Sciences, Seoul National University , Seoul 08826 , South Korea
| | - Bruce Waldman
- 1 Laboratory of Behavioral and Population Ecology, School of Biological Sciences, Seoul National University , Seoul 08826 , South Korea.,2 Department of Integrative Biology, Oklahoma State University , Stillwater, OK 74078 , USA
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Sabino-Pinto J, Martel A, Pasmans F, Steinfartz S, Vences M. Pooling skin swabs does not inhibit qPCR detection of amphibian chytrid infection. PLoS One 2019; 14:e0214405. [PMID: 30939146 PMCID: PMC6445426 DOI: 10.1371/journal.pone.0214405] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 03/12/2019] [Indexed: 11/18/2022] Open
Abstract
Immediate and reliable pathogen detection in large numbers of samples is essential in wildlife disease monitoring and is often realized by DNA-based techniques. Pooling samples increases processing efficiency and reduces processing costs, and has been suggested as a viable technique for quantitative PCR detection of fungal amphibian pathogens of the genus Batrachochytrium. For these fungi, this diagnostic method has been validated by in vitro set ups that provided controlled test conditions but did not take into account potential effects from amphibian skin compounds (e.g. skin secretions and Microbiota) on the approach. Some of these skin compounds are known to cause PCR inhibition in single sample applications and could lead to false negative reactions and thereby hamper pathogen detection. In this study we examined the effect of skin compounds on the pooled extraction method by swabbing individuals of seven amphibian species (one Anura and six Caudata) prior to the inoculation of the swabs with chytrid zoospores. For each species, swabs were extracted in pools of different sizes (from one to four swabs) with only one swab per pool being inoculated with zoospores. There were no significant differences regarding the ability to detect zoospores when comparing pool sizes for any species, with a tendency for more false negatives when the inoculated swab had been inoculated with a single zoospore. This study provides further in vivo evidence for the viability of the pooled extraction method for DNA-based detection of pathogens.
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Affiliation(s)
- Joana Sabino-Pinto
- Zoological Institute, Braunschweig University of Technology, Braunschweig, Germany
| | - An Martel
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Frank Pasmans
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Sebastian Steinfartz
- Zoological Institute, Braunschweig University of Technology, Braunschweig, Germany.,University of Leipzig, Institute of Biology, Molecular Evolution and Systematics of Animals, Leipzig, Germany
| | - Miguel Vences
- Zoological Institute, Braunschweig University of Technology, Braunschweig, Germany
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Muletz-Wolz CR, Barnett SE, DiRenzo GV, Zamudio KR, Toledo LF, James TY, Lips KR. Diverse genotypes of the amphibian-killing fungus produce distinct phenotypes through plastic responses to temperature. J Evol Biol 2019; 32:287-298. [PMID: 30650220 DOI: 10.1111/jeb.13413] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 12/03/2018] [Accepted: 01/10/2019] [Indexed: 01/14/2023]
Abstract
Phenotypes are the target of selection and affect the ability of organisms to persist in variable environments. Phenotypes can be influenced directly by genes and/or by phenotypic plasticity. The amphibian-killing fungus Batrachochytrium dendrobatidis (Bd) has a global distribution, unusually broad host range, and high genetic diversity. Phenotypic plasticity may be an important process that allows this pathogen to infect hundreds of species in diverse environments. We quantified phenotypic variation of nine Bd genotypes from two Bd lineages (Global Pandemic Lineage [GPL] and Brazil) and a hybrid (GPL-Brazil) grown at three temperatures (12, 18 and 24°C). We measured five functional traits including two morphological traits (zoospore and zoosporangium sizes) and three life history traits (carrying capacity, time to fastest growth and exponential growth rate) in a phylogenetic framework. Temperature caused highly plastic responses within each genotype, with all Bd genotypes showing phenotypic plasticity in at least three traits. Among genotypes, Bd generally showed the same direction of plastic response to temperature: larger zoosporangia, higher carrying capacity, longer time to fastest growth and slower exponential growth at lower temperatures. The exception was zoospore size, which was highly variable. Our findings indicate that Bd genotypes have evolved novel phenotypes through plastic responses to temperature over very short timescales. High phenotypic variability likely extends to other traits and may facilitate the large host range and rapid spread of Bd.
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Affiliation(s)
- Carly R Muletz-Wolz
- Center for Conservation Genomics, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, District of Columbia.,Department of Biology, University of Maryland, College Park, Maryland
| | - Samuel E Barnett
- Department of Biology, University of Maryland, College Park, Maryland.,School of Integrative Plant Science, Cornell University, Ithaca, New York
| | - Graziella V DiRenzo
- Department of Biology, University of Maryland, College Park, Maryland.,Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, California
| | - Kelly R Zamudio
- Department of Ecology & Evolutionary Biology, Cornell University, Ithaca, New York
| | - Luís Felipe Toledo
- Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas, São Paulo, Brazil
| | - Timothy Y James
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan
| | - Karen R Lips
- Department of Biology, University of Maryland, College Park, Maryland
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Jenkinson TS, Rodriguez D, Clemons RA, Michelotti LA, Zamudio KR, Toledo LF, Longcore JE, James TY. Globally invasive genotypes of the amphibian chytrid outcompete an enzootic lineage in coinfections. Proc Biol Sci 2018; 285:20181894. [PMID: 30963903 PMCID: PMC6304064 DOI: 10.1098/rspb.2018.1894] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 11/19/2018] [Indexed: 01/22/2023] Open
Abstract
Competition between genotypes is likely to be a key driver of pathogen evolution, particularly following a geographical invasion by distant strains. Theory predicts that competition between disease strains will result in the most virulent strain persisting. Despite its evolutionary implications, the role of strain competition in shaping populations remains untested for most pathogens. We experimentally investigated the in vivo competitive differences between two divergent lineages of the amphibian-killing chytrid fungus ( Batrachochytrium dendrobatidis, Bd). These Bd lineages are hypothesized to have diverged in allopatry but been recently brought back into secondary contact by human introduction. Prior studies indicate that a panzootically-distributed, global lineage of Bd was recently introduced into southern Brazil, and is competitively excluding enzootic lineages in the southern Atlantic Forest. To test for differences in competitive ability between invasive and enzootic Brazilian Bd isolates, we coinfected a model host frog system which we developed for this study ( Hymenochirus curtipes). We tracked isolate-specific zoospore production over the course of the coinfection experiment with chip-based digital PCR (dPCR). The globally invasive panzootic lineage had a competitive advantage in spore production especially during the first one to four weeks of infection, and on frogs that eventually succumbed to Bd infection. Our study provides new evidence that competitive pressure resulting from the human movement of pathogen strains can rapidly alter the genetics, community dynamics and spatial epidemiology of pathogens in the wild.
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Affiliation(s)
- Thomas S. Jenkinson
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - David Rodriguez
- Department of Biology, Texas State University, San Marcos, TX 78666, USA
| | - Rebecca A. Clemons
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Lucas A. Michelotti
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Kelly R. Zamudio
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
| | - L. Felipe Toledo
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, SP 13083-862, Brazil
| | - Joyce E. Longcore
- School of Biology and Ecology, University of Maine, Orono, ME 04469, USA
| | - Timothy Y. James
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
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30
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Single-Phase PacBio
De Novo
Assembly of the Genome of the Chytrid Fungus
Batrachochytrium dendrobatidis,
a Pathogen of Amphibia. Microbiol Resour Announc 2018; 7:MRA01348-18. [PMID: 30533847 PMCID: PMC6284735 DOI: 10.1128/mra.01348-18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 11/05/2018] [Indexed: 11/20/2022] Open
Abstract
Here, we present an updated genome assembly of the diploid chytrid fungus Batrachochytrium dendrobatidis strain RTP6. This strain is part of the global panzootic lineage (BdGPL) and was isolated in Dunedin, New Zealand. Here, we present an updated genome assembly of the diploid chytrid fungus Batrachochytrium dendrobatidis strain RTP6. This strain is part of the global panzootic lineage (BdGPL) and was isolated in Dunedin, New Zealand. The assembly was generated using PacBio long-read and Illumina short-read data, allowing for the accurate phasing of heterozygosities.
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32
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Transcriptional Heterogeneity of Cryptococcus gattii VGII Compared with Non-VGII Lineages Underpins Key Pathogenicity Pathways. mSphere 2018; 3:3/5/e00445-18. [PMID: 30355668 PMCID: PMC6200987 DOI: 10.1128/msphere.00445-18] [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] [Indexed: 11/25/2022] Open
Abstract
The transcriptional profiles of related pathogens and their responses to host-induced stresses underpin their pathogenicity. Expression differences between related pathogens during host interaction can indicate when and how these genes contribute to virulence, ultimately informing new and improved treatment strategies for those diseases. In this paper, we compare the transcriptional profiles of five isolates representing four lineages of C. gattii in rich media. Our analyses identified key processes, including those involving cell capsule, ergosterol production, and melanin, that are differentially expressed between lineages, and we found that VGII has the most distinct profile in terms of numbers of differentially expressed genes. All lineages have also undergone subfunctionalization for several paralogs, including capsule biosynthesis and attachment genes. Most genes appeared downregulated during coincubation with macrophages, with the largest decrease observed for capsule attachment genes, which appeared to be coordinated with a stress response, as all lineages also upregulated oxidative stress response genes. Furthermore, VGII upregulated many genes that are linked to ergosterol biosynthesis and switched from expression of the laccase LAC1 to expression of LAC2 ex vivo. Finally, we saw a pronounced increase in the FosB/Jun/Egr1 regulatory proteins at early time points in bone marrow-derived macrophages, marking a role in the host response to C. gattii. This work highlights the dynamic roles of key C. gattii virulence genes in response to macrophages. Cryptococcus gattii is a pathogenic yeast of humans and other animals which causes disease predominantly in immunocompetent hosts. Infection begins when aerosolized yeast or spores enter the body, triggering an immune response, including engulfment by macrophages. To understand the early transcriptional signals in both the yeast and its mammalian host, we performed a time-course dual-transcriptome sequencing (RNA-seq) experiment for four lineages of C. gattii (lineages VGI to IV) interacting with mouse macrophages at 1, 3, and 6 h postinfection. Comparisons of in vitro to ex vivo gene expression levels indicated that lineage VGII is transcriptionally divergent from non-VGII lineages, including differential expression of genes involved in capsule synthesis, capsule attachment, and ergosterol production. Several paralogous genes demonstrated subfunctionalization between lineages, including upregulation of capsule biosynthesis-related gene CAP2 and downregulation of CAP1 in VGIII. Isolates also compensate for lineage-specific gene losses by overexpression of genetically similar paralogs, including overexpression of capsule gene CAS3 in VGIV, which have lost the CAS31 gene. Differential expression of one in five C. gattii genes was detected following coincubation with mouse macrophages; all isolates showed high induction of oxidative-reduction functions and downregulation of capsule attachment genes. We also found that VGII switches expression of two laccase paralogs (from LAC1 to LAC2) during coincubation of macrophages. Finally, we found that mouse macrophages respond to all four lineages of C. gattii by upregulating FosB/Jun/Egr1 regulatory proteins at early time points. This report highlights the evolutionary breadth of expression profiles among the lineages of C. gattii and the diversity of transcriptional responses at this host-pathogen interface. IMPORTANCE The transcriptional profiles of related pathogens and their responses to host-induced stresses underpin their pathogenicity. Expression differences between related pathogens during host interaction can indicate when and how these genes contribute to virulence, ultimately informing new and improved treatment strategies for those diseases. In this paper, we compare the transcriptional profiles of five isolates representing four lineages of C. gattii in rich media. Our analyses identified key processes, including those involving cell capsule, ergosterol production, and melanin, that are differentially expressed between lineages, and we found that VGII has the most distinct profile in terms of numbers of differentially expressed genes. All lineages have also undergone subfunctionalization for several paralogs, including capsule biosynthesis and attachment genes. Most genes appeared downregulated during coincubation with macrophages, with the largest decrease observed for capsule attachment genes, which appeared to be coordinated with a stress response, as all lineages also upregulated oxidative stress response genes. Furthermore, VGII upregulated many genes that are linked to ergosterol biosynthesis and switched from expression of the laccase LAC1 to expression of LAC2 ex vivo. Finally, we saw a pronounced increase in the FosB/Jun/Egr1 regulatory proteins at early time points in bone marrow-derived macrophages, marking a role in the host response to C. gattii. This work highlights the dynamic roles of key C. gattii virulence genes in response to macrophages.
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Wheeler NJ, Dinguirard N, Marquez J, Gonzalez A, Zamanian M, Yoshino TP, Castillo MG. Sequence and structural variation in the genome of the Biomphalaria glabrata embryonic (Bge) cell line. Parasit Vectors 2018; 11:496. [PMID: 30180879 PMCID: PMC6122571 DOI: 10.1186/s13071-018-3059-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 08/13/2018] [Indexed: 12/15/2022] Open
Abstract
Background The aquatic pulmonate snail Biomphalaria glabrata is a significant vector and laboratory host for the parasitic flatworm Schistosoma mansoni, an etiological agent for the neglected tropical disease schistosomiasis. Much is known regarding the host-parasite interactions of these two organisms, and the B. glabrata embryonic (Bge) cell line has been an invaluable resource in these studies. The B. glabrata BB02 genome sequence was recently released, but nothing is known of the sequence variation between this reference and the Bge cell genome, which has likely accumulated substantial genetic variation in the ~50 years since its isolation. Results Here, we report the genome sequence of our laboratory subculture of the Bge cell line (designated Bge3), which we mapped to the B. glabrata BB02 reference genome. Single nucleotide variants (SNVs) were predicted and focus was given to those SNVs that are most likely to affect the structure or expression of protein-coding genes. Furthermore, we have highlighted and validated high-impact SNVs in genes that have often been studied using Bge cells as an in vitro model, and other genes that may have contributed to the immortalization of this cell line. We also resolved representative karyotypes for the Bge3 subculture, which revealed a mixed population exhibiting substantial aneuploidy, in line with previous reports from other Bge subcultures. Conclusions The Bge3 genome differs from the B. glabrata BB02 reference genome in both sequence and structure, and these are likely to have significant biological effects. The availability of the Bge3 genome sequence, and an awareness of genomic differences with B. glabrata, will inform the design of experiments to understand gene function in this unique in vitro snail cell model. Additionally, this resource will aid in the development of new technologies and molecular approaches that promise to reveal more about this schistosomiasis-transmitting snail vector. Electronic supplementary material The online version of this article (10.1186/s13071-018-3059-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Nicolas J Wheeler
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA
| | - Nathalie Dinguirard
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA
| | - Joshua Marquez
- Department of Biology, New Mexico State University, Las Cruces, NM, USA
| | - Adrian Gonzalez
- Department of Biology, New Mexico State University, Las Cruces, NM, USA
| | - Mostafa Zamanian
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA
| | - Timothy P Yoshino
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA
| | - Maria G Castillo
- Department of Biology, New Mexico State University, Las Cruces, NM, USA.
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Pais M, Yoshida K, Giannakopoulou A, Pel MA, Cano LM, Oliva RF, Witek K, Lindqvist-Kreuze H, Vleeshouwers VGAA, Kamoun S. Gene expression polymorphism underpins evasion of host immunity in an asexual lineage of the Irish potato famine pathogen. BMC Evol Biol 2018; 18:93. [PMID: 29973156 PMCID: PMC6032779 DOI: 10.1186/s12862-018-1201-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 05/22/2018] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Outbreaks caused by asexual lineages of fungal and oomycete pathogens are a continuing threat to crops, wild animals and natural ecosystems (Fisher MC, Henk DA, Briggs CJ, Brownstein JS, Madoff LC, McCraw SL, Gurr SJ, Nature 484:186-194, 2012; Kupferschmidt K, Science 337:636-638, 2012). However, the mechanisms underlying genome evolution and phenotypic plasticity in asexual eukaryotic microbes remain poorly understood (Seidl MF, Thomma BP, BioEssays 36:335-345, 2014). Ever since the 19th century Irish famine, the oomycete Phytophthora infestans has caused recurrent outbreaks on potato and tomato crops that have been primarily caused by the successive rise and migration of pandemic asexual lineages (Goodwin SB, Cohen BA, Fry WE, Proc Natl Acad Sci USA 91:11591-11595, 1994; Yoshida K, Burbano HA, Krause J, Thines M, Weigel D, Kamoun S, PLoS Pathog 10:e1004028, 2014; Yoshida K, Schuenemann VJ, Cano LM, Pais M, Mishra B, Sharma R, Lanz C, Martin FN, Kamoun S, Krause J, et al. eLife 2:e00731, 2013; Cooke DEL, Cano LM, Raffaele S, Bain RA, Cooke LR, Etherington GJ, Deahl KL, Farrer RA, Gilroy EM, Goss EM, et al. PLoS Pathog 8:e1002940, 2012). However, the dynamics of genome evolution within these clonal lineages have not been determined. The objective of this study was to use a comparative genomics and transcriptomics approach to determine the molecular mechanisms that underpin phenotypic variation within a clonal lineage of P. infestans. RESULTS Here, we reveal patterns of genomic and gene expression variation within a P. infestans asexual lineage by comparing strains belonging to the South American EC-1 clone that has dominated Andean populations since the 1990s (Yoshida K, Burbano HA, Krause J, Thines M, Weigel D, Kamoun S, PLoS Pathog 10e1004028, 2014; Yoshida K, Schuenemann VJ, Cano LM, Pais M, Mishra B, Sharma R, Lanz C, Martin FN, Kamoun S, Krause J, et al. eLife 2:e00731, 2013; Delgado RA, Monteros-Altamirano AR, Li Y, Visser RGF, van der Lee TAJ, Vosman B, Plant Pathol 62:1081-1088, 2013; Forbes GA, Escobar XC, Ayala CC, Revelo J, Ordonez ME, Fry BA, Doucett K, Fry WE, Phytopathology 87:375-380, 1997; Oyarzun PJ, Pozo A, Ordonez ME, Doucett K, Forbes GA, Phytopathology 88:265-271, 1998). We detected numerous examples of structural variation, nucleotide polymorphisms and loss of heterozygosity within the EC-1 clone. Remarkably, 17 genes are not expressed in one of the two EC-1 isolates despite apparent absence of sequence polymorphisms. Among these, silencing of an effector gene was associated with evasion of disease resistance conferred by a potato immune receptor. CONCLUSIONS Our findings highlight the molecular changes underpinning the exceptional genetic and phenotypic plasticity associated with host adaptation in a pandemic clonal lineage of a eukaryotic plant pathogen. We observed that the asexual P. infestans lineage EC-1 can exhibit phenotypic plasticity in the absence of apparent genetic mutations resulting in virulence on a potato carrying the Rpi-vnt1.1 gene. Such variant alleles may be epialleles that arose through epigenetic changes in the underlying genes.
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Affiliation(s)
- Marina Pais
- The Sainsbury Laboratory, Norwich Research Park, Colney Ln, Norwich, NR4 7UH UK
| | - Kentaro Yoshida
- The Sainsbury Laboratory, Norwich Research Park, Colney Ln, Norwich, NR4 7UH UK
- Graduate School of Agricultural Science, Kobe University, Kobe, Japan
| | - Artemis Giannakopoulou
- The Sainsbury Laboratory, Norwich Research Park, Colney Ln, Norwich, NR4 7UH UK
- National Hellenic Research Foundation, Institute of Biology, Medicinal Chemistry & Biotechnology, Athens, Greece
| | - Mathieu A. Pel
- Wageningen UR Plant Breeding, Wageningen, The Netherlands
| | - Liliana M. Cano
- The Sainsbury Laboratory, Norwich Research Park, Colney Ln, Norwich, NR4 7UH UK
- Institute of Food and Agricultural Sciences, Department of Plant Pathology, Indian River Research and Education Center, University of Florida, Fort Pierce, FL USA
| | - Ricardo F. Oliva
- The Sainsbury Laboratory, Norwich Research Park, Colney Ln, Norwich, NR4 7UH UK
- Genetics and Biotechnology Division, International Rice Research Institute, Los Baños, Philippines
| | - Kamil Witek
- The Sainsbury Laboratory, Norwich Research Park, Colney Ln, Norwich, NR4 7UH UK
| | | | | | - Sophien Kamoun
- The Sainsbury Laboratory, Norwich Research Park, Colney Ln, Norwich, NR4 7UH UK
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Fisher MC, Ghosh P, Shelton JMG, Bates K, Brookes L, Wierzbicki C, Rosa GM, Farrer RA, Aanensen DM, Alvarado-Rybak M, Bataille A, Berger L, Böll S, Bosch J, Clare FC, A Courtois E, Crottini A, Cunningham AA, Doherty-Bone TM, Gebresenbet F, Gower DJ, Höglund J, James TY, Jenkinson TS, Kosch TA, Lambertini C, Laurila A, Lin CF, Loyau A, Martel A, Meurling S, Miaud C, Minting P, Ndriantsoa S, O'Hanlon SJ, Pasmans F, Rakotonanahary T, Rabemananjara FCE, Ribeiro LP, Schmeller DS, Schmidt BR, Skerratt L, Smith F, Soto-Azat C, Tessa G, Toledo LF, Valenzuela-Sánchez A, Verster R, Vörös J, Waldman B, Webb RJ, Weldon C, Wombwell E, Zamudio KR, Longcore JE, Garner TWJ. Development and worldwide use of non-lethal, and minimal population-level impact, protocols for the isolation of amphibian chytrid fungi. Sci Rep 2018; 8:7772. [PMID: 29773857 PMCID: PMC5958081 DOI: 10.1038/s41598-018-24472-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 03/23/2018] [Indexed: 11/09/2022] Open
Abstract
Parasitic chytrid fungi have emerged as a significant threat to amphibian species worldwide, necessitating the development of techniques to isolate these pathogens into culture for research purposes. However, early methods of isolating chytrids from their hosts relied on killing amphibians. We modified a pre-existing protocol for isolating chytrids from infected animals to use toe clips and biopsies from toe webbing rather than euthanizing hosts, and distributed the protocol to researchers as part of the BiodivERsA project RACE; here called the RML protocol. In tandem, we developed a lethal procedure for isolating chytrids from tadpole mouthparts. Reviewing a database of use a decade after their inception, we find that these methods have been applied across 5 continents, 23 countries and in 62 amphibian species. Isolation of chytrids by the non-lethal RML protocol occured in 18% of attempts with 207 fungal isolates and three species of chytrid being recovered. Isolation of chytrids from tadpoles occured in 43% of attempts with 334 fungal isolates of one species (Batrachochytrium dendrobatidis) being recovered. Together, these methods have resulted in a significant reduction and refinement of our use of threatened amphibian species and have improved our ability to work with this group of emerging pathogens.
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Affiliation(s)
- Matthew C Fisher
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus), Imperial College London, London, W2 1PG, UK.
| | - Pria Ghosh
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus), Imperial College London, London, W2 1PG, UK.,Unit for Environmental Sciences and Management, Private Bag x6001, North-West University, Potchefstroom, 2520, South Africa
| | - Jennifer M G Shelton
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus), Imperial College London, London, W2 1PG, UK
| | - Kieran Bates
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus), Imperial College London, London, W2 1PG, UK
| | - Lola Brookes
- Institute of Zoology, Regent's Park, London, NW1 4RY, UK
| | - Claudia Wierzbicki
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus), Imperial College London, London, W2 1PG, UK
| | - Gonçalo M Rosa
- Institute of Zoology, Regent's Park, London, NW1 4RY, UK.,Centre for Ecology, Evolution and Environmental Changes (CE3C), Faculdade de Ciências da Universidade de Lisboa, Lisboa, Portugal
| | - Rhys A Farrer
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus), Imperial College London, London, W2 1PG, UK
| | - David M Aanensen
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus), Imperial College London, London, W2 1PG, UK.,Centre for Genomic Pathogen Surveillance, Wellcome Genome Campus, Cambridgeshire, UK
| | - Mario Alvarado-Rybak
- Centro de Investigación para la Sustentabilidad, Facultad de Ecología y Recursos Naturales, Universidad Andres Bello, Republica 440, Santiago, Chile
| | - Arnaud Bataille
- Laboratory of Behavioral and Population Ecology, School of Biological Sciences, Seoul National University, Seoul, 08826, South Korea.,CIRAD, UMR ASTRE, F-34398 Montpellier, France; ASTRE, Univ Montpellier, CIRAD, INRA, Montpellier, France
| | - Lee Berger
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, 4811, Australia
| | - Susanne Böll
- Agency for Population Ecology and Nature Conservancy, Gerbrunn, Germany
| | - Jaime Bosch
- Museo Nacional de Ciencias Naturales, CSIC c/Jose Gutierrez Abascal 2, 28006, Madrid, Spain
| | - Frances C Clare
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus), Imperial College London, London, W2 1PG, UK
| | - Elodie A Courtois
- Laboratoire Ecologie, évolution, interactions des systèmes amazoniens (LEEISA), Université de Guyane, CNRS, IFREMER, 97300, Cayenne, French Guiana
| | - Angelica Crottini
- CIBIO - Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Universidade do Porto, 4485-661, Vairão, Portugal
| | | | | | - Fikirte Gebresenbet
- Department of Integrative Biology, Oklahoma State University, 113 Life Sciences West, Stillwater, OK, 74078, USA
| | - David J Gower
- Life Sciences, The Natural History Museum, London, SW7 5BD, UK
| | - Jacob Höglund
- Department of Ecology and Genetics, EBC, Uppsala University, Norbyv. 18D, SE-75236, Uppsala, Sweden
| | - Timothy Y James
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, 48109, USA
| | - Thomas S Jenkinson
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, 48109, USA
| | - Tiffany A Kosch
- Laboratory of Behavioral and Population Ecology, School of Biological Sciences, Seoul National University, Seoul, 08826, South Korea.,One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, 4811, Australia
| | - Carolina Lambertini
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo, 13083-862, Brazil
| | - Anssi Laurila
- Department of Ecology and Genetics, EBC, Uppsala University, Norbyv. 18D, SE-75236, Uppsala, Sweden
| | - Chun-Fu Lin
- Zoology Division, Endemic Species Research Institute, 1 Ming-shen East Road, Jiji, Nantou, 552, Taiwan
| | - Adeline Loyau
- Helmholtz Centre for Environmental Research - UFZ, Department of Conservation Biology, Permoserstrasse 15, 04318, Leipzig, Germany.,ECOLAB, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - An Martel
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820, Merelbeke, Belgium
| | - Sara Meurling
- Department of Ecology and Genetics, EBC, Uppsala University, Norbyv. 18D, SE-75236, Uppsala, Sweden
| | - Claude Miaud
- PSL Research University, CEFE UMR 5175, CNRS, Université de Montpellier, Université Paul-Valéry Montpellier, EPHE, Biogéographie et Ecologie des vertébrés, Montpellier, France
| | - Pete Minting
- Amphibian and Reptile Conservation (ARC) Trust, 655A Christchurch Road, Boscombe, Bournemouth, Dorset, BH1 4AP, UK
| | - Serge Ndriantsoa
- Durrell Wildlife Conservation Trust, Madagascar Programme, Antananarivo, Madagascar
| | - Simon J O'Hanlon
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus), Imperial College London, London, W2 1PG, UK.,Institute of Zoology, Regent's Park, London, NW1 4RY, UK
| | - Frank Pasmans
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820, Merelbeke, Belgium
| | | | - Falitiana C E Rabemananjara
- Durrell Wildlife Conservation Trust, Madagascar Programme, Antananarivo, Madagascar.,IUCN SSC Amphibian Specialist Group-Madagascar, 101, Antananarivo, Madagascar
| | - Luisa P Ribeiro
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo, 13083-862, Brazil
| | - Dirk S Schmeller
- Helmholtz Centre for Environmental Research - UFZ, Department of Conservation Biology, Permoserstrasse 15, 04318, Leipzig, Germany.,ECOLAB, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - Benedikt R Schmidt
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.,Info Fauna Karch, Université de Neuchâtel, Bellevaux 51, UniMail Bâtiment 6, 2000, Neuchâtel, Switzerland
| | - Lee Skerratt
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, 4811, Australia
| | - Freya Smith
- National Wildlife Management Centre, APHA, Woodchester Park, Gloucestershire, GL10 3UJ, UK
| | - Claudio Soto-Azat
- Centro de Investigación para la Sustentabilidad, Facultad de Ecología y Recursos Naturales, Universidad Andres Bello, Republica 440, Santiago, Chile
| | - Giulia Tessa
- Non-profit Association Zirichiltaggi - Sardinia Wildlife Conservation, Strada Vicinale Filigheddu 62/C, I-07100, Sassari, Italy
| | - Luís Felipe Toledo
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo, 13083-862, Brazil
| | - Andrés Valenzuela-Sánchez
- Centro de Investigación para la Sustentabilidad, Facultad de Ecología y Recursos Naturales, Universidad Andres Bello, Republica 440, Santiago, Chile.,ONG Ranita de Darwin, Nataniel Cox 152, Santiago, Chile
| | - Ruhan Verster
- Unit for Environmental Sciences and Management, Private Bag x6001, North-West University, Potchefstroom, 2520, South Africa
| | - Judit Vörös
- Collection of Amphibians and Reptiles, Department of Zoology, Hungarian Natural History Museum, Budapest, Baross u, 13., 1088, Hungary
| | - Bruce Waldman
- Laboratory of Behavioral and Population Ecology, School of Biological Sciences, Seoul National University, Seoul, 08826, South Korea
| | - Rebecca J Webb
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, 4811, Australia
| | - Che Weldon
- Unit for Environmental Sciences and Management, Private Bag x6001, North-West University, Potchefstroom, 2520, South Africa
| | - Emma Wombwell
- Institute of Zoology, Regent's Park, London, NW1 4RY, UK
| | - Kelly R Zamudio
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, 14853, USA
| | - Joyce E Longcore
- School of Biology and Ecology, University of Maine, Orono, Maine, 04469, USA
| | - Trenton W J Garner
- Institute of Zoology, Regent's Park, London, NW1 4RY, UK.,Non-profit Association Zirichiltaggi - Sardinia Wildlife Conservation, Strada Vicinale Filigheddu 62/C, I-07100, Sassari, Italy.,Unit for Environmental Sciences and Management, Private Bag x6001, North-West University, Potchefstroom, 2520, South Africa
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36
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O'Hanlon SJ, Rieux A, Farrer RA, Rosa GM, Waldman B, Bataille A, Kosch TA, Murray KA, Brankovics B, Fumagalli M, Martin MD, Wales N, Alvarado-Rybak M, Bates KA, Berger L, Böll S, Brookes L, Clare F, Courtois EA, Cunningham AA, Doherty-Bone TM, Ghosh P, Gower DJ, Hintz WE, Höglund J, Jenkinson TS, Lin CF, Laurila A, Loyau A, Martel A, Meurling S, Miaud C, Minting P, Pasmans F, Schmeller DS, Schmidt BR, Shelton JMG, Skerratt LF, Smith F, Soto-Azat C, Spagnoletti M, Tessa G, Toledo LF, Valenzuela-Sánchez A, Verster R, Vörös J, Webb RJ, Wierzbicki C, Wombwell E, Zamudio KR, Aanensen DM, James TY, Gilbert MTP, Weldon C, Bosch J, Balloux F, Garner TWJ, Fisher MC. Recent Asian origin of chytrid fungi causing global amphibian declines. Science 2018; 360:621-627. [PMID: 29748278 PMCID: PMC6311102 DOI: 10.1126/science.aar1965] [Citation(s) in RCA: 282] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Accepted: 03/29/2018] [Indexed: 12/14/2022]
Abstract
Globalized infectious diseases are causing species declines worldwide, but their source often remains elusive. We used whole-genome sequencing to solve the spatiotemporal origins of the most devastating panzootic to date, caused by the fungus Batrachochytrium dendrobatidis, a proximate driver of global amphibian declines. We traced the source of B. dendrobatidis to the Korean peninsula, where one lineage, BdASIA-1, exhibits the genetic hallmarks of an ancestral population that seeded the panzootic. We date the emergence of this pathogen to the early 20th century, coinciding with the global expansion of commercial trade in amphibians, and we show that intercontinental transmission is ongoing. Our findings point to East Asia as a geographic hotspot for B. dendrobatidis biodiversity and the original source of these lineages that now parasitize amphibians worldwide.
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Affiliation(s)
- Simon J O'Hanlon
- Department of Infectious Disease Epidemiology and MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London W2 1PG, UK.
- Institute of Zoology, Regent's Park, London NW1 4RY, UK
| | - Adrien Rieux
- CIRAD, UMR PVBMT, 97410 St. Pierre, Reunion, France
| | - Rhys A Farrer
- Department of Infectious Disease Epidemiology and MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London W2 1PG, UK
| | - Gonçalo M Rosa
- Institute of Zoology, Regent's Park, London NW1 4RY, UK
- Department of Biology, University of Nevada, Reno, NV 89557, USA
- Centre for Ecology, Evolution and Environmental Changes (CE3C), Faculdade de Ciências da Universidade de Lisboa, Lisboa, Portugal
| | - Bruce Waldman
- Laboratory of Behavioral and Population Ecology, School of Biological Sciences, Seoul National University, Seoul 08826, South Korea
| | - Arnaud Bataille
- Laboratory of Behavioral and Population Ecology, School of Biological Sciences, Seoul National University, Seoul 08826, South Korea
- CIRAD, UMR ASTRE, F-34398 Montpellier, France
| | - Tiffany A Kosch
- Laboratory of Behavioral and Population Ecology, School of Biological Sciences, Seoul National University, Seoul 08826, South Korea
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland 4811, Australia
| | - Kris A Murray
- Department of Infectious Disease Epidemiology and MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London W2 1PG, UK
| | - Balázs Brankovics
- Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584CT Utrecht, Netherlands
- Institute of Biodiversity and Ecosystem Dynamics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, Netherlands
| | - Matteo Fumagalli
- Department of Life Sciences, Silwood Park Campus, Imperial College London, Ascot, UK
- UCL Genetics Institute, University College London, London WC1E 6BT, UK
| | - Michael D Martin
- Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology (NTNU), Erling Skakkes gate 49, NO-7012 Trondheim, Norway
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, 1350 Copenhagen, Denmark
| | - Nathan Wales
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, 1350 Copenhagen, Denmark
| | - Mario Alvarado-Rybak
- Centro de Investigación para la Sustentabilidad, Facultad de Ecología y Recursos Naturales, Universidad Andres Bello, Republica 440, Santiago, Chile
| | - Kieran A Bates
- Department of Infectious Disease Epidemiology and MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London W2 1PG, UK
- Institute of Zoology, Regent's Park, London NW1 4RY, UK
| | - Lee Berger
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland 4811, Australia
| | - Susanne Böll
- Agency for Population Ecology and Nature Conservancy, Gerbrunn, Germany
| | - Lola Brookes
- Institute of Zoology, Regent's Park, London NW1 4RY, UK
| | - Frances Clare
- Department of Infectious Disease Epidemiology and MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London W2 1PG, UK
- Institute of Zoology, Regent's Park, London NW1 4RY, UK
| | - Elodie A Courtois
- Laboratoire Ecologie, Évolution, Interactions des Systèmes Amazoniens (LEEISA), Université de Guyane, CNRS, IFREMER, 97300 Cayenne, French Guiana
| | | | | | - Pria Ghosh
- Department of Infectious Disease Epidemiology and MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London W2 1PG, UK
- Unit for Environmental Sciences and Management, Private Bag x6001, North-West University, Potchefstroom 2520, South Africa
| | - David J Gower
- Life Sciences, Natural History Museum, London SW7 5BD, UK
| | - William E Hintz
- Biology Department, University of Victoria, Victoria, BC V8W 3N5, Canada
| | - Jacob Höglund
- Department of Ecology and Genetics, EBC, Uppsala University, Norbyv. 18D, SE-75236, Uppsala, Sweden
| | - Thomas S Jenkinson
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Chun-Fu Lin
- Zoology Division, Endemic Species Research Institute, 1 Ming-shen East Road, Jiji, Nantou 552, Taiwan
| | - Anssi Laurila
- Department of Ecology and Genetics, EBC, Uppsala University, Norbyv. 18D, SE-75236, Uppsala, Sweden
| | - Adeline Loyau
- Department of Conservation Biology, Helmholtz Centre for Environmental Research-UFZ, 04318 Leipzig, Germany
- EcoLab, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - An Martel
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, B-9820 Merelbeke, Belgium
| | - Sara Meurling
- Department of Ecology and Genetics, EBC, Uppsala University, Norbyv. 18D, SE-75236, Uppsala, Sweden
| | - Claude Miaud
- PSL Research University, CEFE UMR 5175, CNRS, Université de Montpellier, Université Paul-Valéry Montpellier, EPHE, Montpellier, France
| | - Pete Minting
- Amphibian and Reptile Conservation (ARC) Trust, Boscombe, Bournemouth, Dorset BH1 4AP, UK
| | - Frank Pasmans
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, B-9820 Merelbeke, Belgium
| | - Dirk S Schmeller
- Department of Conservation Biology, Helmholtz Centre for Environmental Research-UFZ, 04318 Leipzig, Germany
- EcoLab, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - Benedikt R Schmidt
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, 8057 Zurich, Switzerland, and Info Fauna Karch, UniMail-Bâtiment G, Bellevaux 51, 2000 Neuchâtel, Switzerland
| | - Jennifer M G Shelton
- Department of Infectious Disease Epidemiology and MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London W2 1PG, UK
| | - Lee F Skerratt
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland 4811, Australia
| | - Freya Smith
- Institute of Zoology, Regent's Park, London NW1 4RY, UK
- National Wildlife Management Centre, APHA, Woodchester Park, Gloucestershire GL10 3UJ, UK
| | - Claudio Soto-Azat
- Centro de Investigación para la Sustentabilidad, Facultad de Ecología y Recursos Naturales, Universidad Andres Bello, Republica 440, Santiago, Chile
| | | | - Giulia Tessa
- Non-profit Association Zirichiltaggi-Sardinia Wildlife Conservation, Strada Vicinale Filigheddu 62/C, I-07100 Sassari, Italy
| | - Luís Felipe Toledo
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Departamento de Biologia Animal, Instituto de Biologia, Unicamp, Campinas, Brazil
| | - Andrés Valenzuela-Sánchez
- Centro de Investigación para la Sustentabilidad, Facultad de Ecología y Recursos Naturales, Universidad Andres Bello, Republica 440, Santiago, Chile
- ONG Ranita de Darwin, Nataniel Cox 152, Santiago, Chile
| | - Ruhan Verster
- Unit for Environmental Sciences and Management, Private Bag x6001, North-West University, Potchefstroom 2520, South Africa
| | - Judit Vörös
- Collection of Amphibians and Reptiles, Department of Zoology, Hungarian Natural History Museum, Budapest, Baross u. 13., 1088, Hungary
| | - Rebecca J Webb
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland 4811, Australia
| | - Claudia Wierzbicki
- Department of Infectious Disease Epidemiology and MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London W2 1PG, UK
| | - Emma Wombwell
- Institute of Zoology, Regent's Park, London NW1 4RY, UK
| | - Kelly R Zamudio
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
| | - David M Aanensen
- Department of Infectious Disease Epidemiology and MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London W2 1PG, UK
- Centre for Genomic Pathogen Surveillance, Wellcome Genome Campus, Cambridgeshire, UK
| | - Timothy Y James
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - M Thomas P Gilbert
- Department of Natural History, NTNU University Museum, Norwegian University of Science and Technology (NTNU), Erling Skakkes gate 49, NO-7012 Trondheim, Norway
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, 1350 Copenhagen, Denmark
| | - Ché Weldon
- Unit for Environmental Sciences and Management, Private Bag x6001, North-West University, Potchefstroom 2520, South Africa
| | - Jaime Bosch
- Museo Nacional de Ciencias Naturales, CSIC c/ Jose Gutierrez Abascal 2, 28006 Madrid, Spain
| | - François Balloux
- UCL Genetics Institute, University College London, London WC1E 6BT, UK
| | - Trenton W J Garner
- Institute of Zoology, Regent's Park, London NW1 4RY, UK
- Unit for Environmental Sciences and Management, Private Bag x6001, North-West University, Potchefstroom 2520, South Africa
- Non-profit Association Zirichiltaggi-Sardinia Wildlife Conservation, Strada Vicinale Filigheddu 62/C, I-07100 Sassari, Italy
| | - Matthew C Fisher
- Department of Infectious Disease Epidemiology and MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London W2 1PG, UK.
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37
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Abstract
The first eukaryotic genome to be sequenced was fungal, and there continue to be more sequenced genomes in the kingdom Fungi than in any other eukaryotic kingdom. Comparison of these genomes reveals many sources of genetic variation, from single nucleotide polymorphisms to horizontal gene transfer and on to changes in the arrangement and number of chromosomes, not to mention endofungal bacteria and viruses. Population genomics shows that all sources generate variation all the time and implicate natural selection as the force maintaining genome stability. Variation in wild populations is a rich resource for associating genetic variation with phenotypic variation, whether through quantitative trait locus mapping, genome-wide association studies, or reverse ecology. Subjects of studies associating genetic and phenotypic variation include model fungi, e.g., Saccharomyces and Neurospora, but pioneering studies have also been made with fungi pathogenic to plants, e.g., Pyricularia (= Magnaporthe), Zymoseptoria, and Fusarium, and to humans, e.g., Coccidioides, Cryptococcus, and Candida.
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38
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Elliott M, Yuzon J, C MM, Tripathy S, Bui M, Chastagner GA, Coats K, Rizzo DM, Garbelotto M, Kasuga T. Characterization of phenotypic variation and genome aberrations observed among Phytophthora ramorum isolates from diverse hosts. BMC Genomics 2018; 19:320. [PMID: 29720102 PMCID: PMC5932867 DOI: 10.1186/s12864-018-4709-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 04/22/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Accumulating evidence suggests that genome plasticity allows filamentous plant pathogens to adapt to changing environments. Recently, the generalist plant pathogen Phytophthora ramorum has been documented to undergo irreversible phenotypic alterations accompanied by chromosomal aberrations when infecting trunks of mature oak trees (genus Quercus). In contrast, genomes and phenotypes of the pathogen derived from the foliage of California bay (Umbellularia californica) are usually stable. We define this phenomenon as host-induced phenotypic diversification (HIPD). P. ramorum also causes a severe foliar blight in some ornamental plants such as Rhododendron spp. and Viburnum spp., and isolates from these hosts occasionally show phenotypes resembling those from oak trunks that carry chromosomal aberrations. The aim of this study was to investigate variations in phenotypes and genomes of P. ramorum isolates from non-oak hosts and substrates to determine whether HIPD changes may be equivalent to those among isolates from oaks. RESULTS We analyzed genomes of diverse non-oak isolates including those taken from foliage of Rhododendron and other ornamental plants, as well as from natural host species, soil, and water. Isolates recovered from artificially inoculated oak logs were also examined. We identified diverse chromosomal aberrations including copy neutral loss of heterozygosity (cnLOH) and aneuploidy in isolates from non-oak hosts. Most identified aberrations in non-oak hosts were also common among oak isolates; however, trisomy, a frequent type of chromosomal aberration in oak isolates was not observed in isolates from Rhododendron. CONCLUSION This work cross-examined phenotypic variation and chromosomal aberrations in P. ramorum isolates from oak and non-oak hosts and substrates. The results suggest that HIPD comparable to that occurring in oak hosts occurs in non-oak environments such as in Rhododendron leaves. Rhododendron leaves are more easily available than mature oak stems and thus can potentially serve as a model host for the investigation of HIPD, the newly described plant-pathogen interaction.
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Affiliation(s)
- Marianne Elliott
- Washington State University Puyallup Research and Extension Center, Puyallup, Washington, 98371, USA
| | - Jennifer Yuzon
- Department of Plant Pathology, University of California, Davis, California, 95616, USA
| | - Mathu Malar C
- Computational Genomics Lab, Structural Biology and Bioinformatics Division, CSIR Indian Institute of Chemical Biology, Kolkata, 700032, India
| | - Sucheta Tripathy
- Computational Genomics Lab, Structural Biology and Bioinformatics Division, CSIR Indian Institute of Chemical Biology, Kolkata, 700032, India
| | - Mai Bui
- Crops Pathology and Genetics Research Unit, USDA Agricultural Research Service, Davis, California, 95616, USA
| | - Gary A Chastagner
- Washington State University Puyallup Research and Extension Center, Puyallup, Washington, 98371, USA
| | - Katie Coats
- Washington State University Puyallup Research and Extension Center, Puyallup, Washington, 98371, USA
| | - David M Rizzo
- Department of Plant Pathology, University of California, Davis, California, 95616, USA
| | - Matteo Garbelotto
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, California, 94720, USA
| | - Takao Kasuga
- Crops Pathology and Genetics Research Unit, USDA Agricultural Research Service, Davis, California, 95616, USA.
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39
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Abstract
The ability of an organism to replicate and segregate its genome with high fidelity is vital to its survival and for the production of future generations. Errors in either of these steps (replication or segregation) can lead to a change in ploidy or chromosome number. While these drastic genome changes can be detrimental to the organism, resulting in decreased fitness, they can also provide increased fitness during periods of stress. A change in ploidy or chromosome number can fundamentally change how a cell senses and responds to its environment. Here, we discuss current ideas in fungal biology that illuminate how eukaryotic genome size variation can impact the organism at a cellular and evolutionary level. One of the most fascinating observations from the past 2 decades of research is that some fungi have evolved the ability to tolerate large genome size changes and generate vast genomic heterogeneity without undergoing canonical meiosis.
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40
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Steenwyk JL, Rokas A. Copy Number Variation in Fungi and Its Implications for Wine Yeast Genetic Diversity and Adaptation. Front Microbiol 2018; 9:288. [PMID: 29520259 PMCID: PMC5826948 DOI: 10.3389/fmicb.2018.00288] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 02/07/2018] [Indexed: 11/13/2022] Open
Abstract
In recent years, copy number (CN) variation has emerged as a new and significant source of genetic polymorphisms contributing to the phenotypic diversity of populations. CN variants are defined as genetic loci that, due to duplication and deletion, vary in their number of copies across individuals in a population. CN variants range in size from 50 base pairs to whole chromosomes, can influence gene activity, and are associated with a wide range of phenotypes in diverse organisms, including the budding yeast Saccharomyces cerevisiae. In this review, we introduce CN variation, discuss the genetic and molecular mechanisms implicated in its generation, how they can contribute to genetic and phenotypic diversity in fungal populations, and consider how CN variants may influence wine yeast adaptation in fermentation-related processes. In particular, we focus on reviewing recent work investigating the contribution of changes in CN of fermentation-related genes in yeast wine strains and offer notable illustrations of such changes, including the high levels of CN variation among the CUP genes, which confer resistance to copper, a metal with fungicidal properties, and the preferential deletion and duplication of the MAL1 and MAL3 loci, respectively, which are responsible for metabolizing maltose and sucrose. Based on the available data, we propose that CN variation is a substantial dimension of yeast genetic diversity that occurs largely independent of single nucleotide polymorphisms. As such, CN variation harbors considerable potential for understanding and manipulating yeast strains in the wine fermentation environment and beyond.
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Affiliation(s)
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States
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41
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Antwis RE, Harrison XA. Probiotic consortia are not uniformly effective against different amphibian chytrid pathogen isolates. Mol Ecol 2018; 27:577-589. [PMID: 29218845 DOI: 10.1111/mec.14456] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 11/27/2017] [Indexed: 12/20/2022]
Abstract
Symbiotic bacterial communities can protect their hosts from infection by pathogens. Treatment of wild individuals with protective bacteria (probiotics) isolated from hosts can combat the spread of emerging infectious diseases. However, it is unclear whether candidate probiotic bacteria can offer consistent protection across multiple isolates of globally distributed pathogens. Here, we use the lethal amphibian fungal pathogen Batrachochytrium dendrobatidis to investigate whether probiotic richness (number of bacteria) or genetic distance among consortia members influences broad-scale in vitro inhibitory capabilities of probiotics across multiple isolates of the pathogen. We show that inhibition of multiple pathogen isolates by individual bacteria is rare, with no systematic pattern among bacterial genera in ability to inhibit multiple B. dendrobatidis isolates. Bacterial consortia can offer stronger protection against B. dendrobatidis compared to single strains, and this tended to be more pronounced for consortia containing multiple genera compared with those consisting of bacteria from a single genus (i.e., with lower genetic distance), but critically, this effect was not uniform across all B. dendrobatidis isolates. These novel insights have important implications for the effective design of bacterial probiotics to mitigate emerging infectious diseases.
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Affiliation(s)
- Rachael E Antwis
- School of Environment and Life Sciences, University of Salford, Salford, UK.,Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
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42
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Advancing Understanding of Amphibian Evolution, Ecology, Behavior, and Conservation with Massively Parallel Sequencing. POPULATION GENOMICS 2018. [DOI: 10.1007/13836_2018_61] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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43
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Antwis RE, Weldon C. Amphibian skin defences show variation in ability to inhibit growth of Batrachochytrium dendrobatidis isolates from the Global Panzootic Lineage. MICROBIOLOGY-SGM 2017; 163:1835-1838. [PMID: 29095686 DOI: 10.1099/mic.0.000570] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The fungal pathogen Batrachochytrium dendrobatidis has caused declines and extinctions in hundreds of amphibian species across the world. Virulence varies among and within lineages; the Global Panzootic Lineage (GPL) is the most pathogenic, although there is also variation in lethality among GPL isolates. Amphibians have a number of defences against pathogens, and skin products including the microbiota and host peptides have considerable influence over disease progression. Here we demonstrate that the collective skin products (the mucosome) of two amphibian species show significant variation in their ability to inhibit different globally distributed isolates of GPL. This may in part explain the variation in disease susceptibility of hosts to different strains of B. dendrobatidis. More work is required to identify particular traits associated with mucosomes that confer broad-spectrum inhibition across GPL in order to facilitate the development of prophylaxis and/or treatments for chytridiomycosis in situ.
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Affiliation(s)
- Rachael Ellen Antwis
- School of Environment and Life Sciences, University of Salford, Salford, UK
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
| | - Ché Weldon
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
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44
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Garner TWJ, Schmidt BR, Martel A, Pasmans F, Muths E, Cunningham AA, Weldon C, Fisher MC, Bosch J. Mitigating amphibian chytridiomycoses in nature. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2016.0207. [PMID: 28080996 DOI: 10.1098/rstb.2016.0207] [Citation(s) in RCA: 108] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/12/2016] [Indexed: 12/11/2022] Open
Abstract
Amphibians across the planet face the threat of population decline and extirpation caused by the disease chytridiomycosis. Despite consensus that the fungal pathogens responsible for the disease are conservation issues, strategies to mitigate their impacts in the natural world are, at best, nascent. Reducing risk associated with the movement of amphibians, non-amphibian vectors and other sources of infection remains the first line of defence and a primary objective when mitigating the threat of disease in wildlife. Amphibian-associated chytridiomycete fungi and chytridiomycosis are already widespread, though, and we therefore focus on discussing options for mitigating the threats once disease emergence has occurred in wild amphibian populations. All strategies have shortcomings that need to be overcome before implementation, including stronger efforts towards understanding and addressing ethical and legal considerations. Even if these issues can be dealt with, all currently available approaches, or those under discussion, are unlikely to yield the desired conservation outcome of disease mitigation. The decision process for establishing mitigation strategies requires integrated thinking that assesses disease mitigation options critically and embeds them within more comprehensive strategies for the conservation of amphibian populations, communities and ecosystems.This article is part of the themed issue 'Tackling emerging fungal threats to animal health, food security and ecosystem resilience'.
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Affiliation(s)
- Trenton W J Garner
- Institute of Zoology, Zoological Society of London, Regents Park, NW1 4RY London, UK .,Unit for Environmental Research and Management, North-West University, Potchefstroom 2520, South Africa
| | - Benedikt R Schmidt
- Karch, Passage Maximilien-de-Meuron 6, 2000 Neuchâtel, Switzerland.,Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - An Martel
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Frank Pasmans
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Erin Muths
- U.S. Geological Survey, Fort Collins Science Fort Collins, 2150 Centre Avenue Building C, Fort Collins, CO 80526, USA
| | - Andrew A Cunningham
- Institute of Zoology, Zoological Society of London, Regents Park, NW1 4RY London, UK
| | - Che Weldon
- Unit for Environmental Research and Management, North-West University, Potchefstroom 2520, South Africa
| | - Matthew C Fisher
- Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Jaime Bosch
- Museo Nacional de Ciencias Naturales, CSIC, José Gutiérrez Abascal 2, 28006 Madrid, Spain
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45
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Farrer RA, Fisher MC. Describing Genomic and Epigenomic Traits Underpinning Emerging Fungal Pathogens. ADVANCES IN GENETICS 2017; 100:73-140. [PMID: 29153405 DOI: 10.1016/bs.adgen.2017.09.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
An unprecedented number of pathogenic fungi are emerging and causing disease in animals and plants, putting the resilience of wild and managed ecosystems in jeopardy. While the past decades have seen an increase in the number of pathogenic fungi, they have also seen the birth of new big data technologies and analytical approaches to tackle these emerging pathogens. We review how the linked fields of genomics and epigenomics are transforming our ability to address the challenge of emerging fungal pathogens. We explore the methodologies and bioinformatic toolkits that currently exist to rapidly analyze the genomes of unknown fungi, then discuss how these data can be used to address key questions that shed light on their epidemiology. We show how genomic approaches are leading a revolution into our understanding of emerging fungal diseases and speculate on future approaches that will transform our ability to tackle this increasingly important class of emerging pathogens.
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46
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Muletz-Wolz CR, Almario JG, Barnett SE, DiRenzo GV, Martel A, Pasmans F, Zamudio KR, Toledo LF, Lips KR. Inhibition of Fungal Pathogens across Genotypes and Temperatures by Amphibian Skin Bacteria. Front Microbiol 2017; 8:1551. [PMID: 28871241 PMCID: PMC5566582 DOI: 10.3389/fmicb.2017.01551] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 07/31/2017] [Indexed: 01/20/2023] Open
Abstract
Symbiotic bacteria may dampen the impacts of infectious diseases on hosts by inhibiting pathogen growth. However, our understanding of the generality of pathogen inhibition by different bacterial taxa across pathogen genotypes and environmental conditions is limited. Bacterial inhibitory properties are of particular interest for the amphibian-killing fungal pathogens (Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans), for which probiotic applications as conservation strategies have been proposed. We quantified the inhibition strength of five putatively B. dendrobatidis-inhibitory bacteria isolated from woodland salamander skin against six Batrachochytrium genotypes at two temperatures (12 and 18°C). We selected six genotypes from across the Batrachochytrium phylogeny: B. salamandrivorans, B. dendrobatidis-Brazil and four genotypes of the B. dendrobatidis Global Panzootic Lineage (GPL1: JEL647, JEL404; GPL2: SRS810, JEL423). We performed 96-well plate challenge assays in a full factorial design. We detected a Batrachochytrium genotype by temperature interaction on bacterial inhibition score for all bacteria, indicating that bacteria vary in ability to inhibit Batrachochytrium depending on pathogen genotype and temperature. Acinetobacter rhizosphaerae moderately inhibited B. salamandrivorans at both temperatures (μ = 46–53%), but not any B. dendrobatidis genotypes. Chryseobacterium sp. inhibited three Batrachochytrium genotypes at both temperatures (μ = 5–71%). Pseudomonas sp. strain 1 inhibited all Batrachochytrium genotypes at 12°C and four Batrachochytrium genotypes at 18°C (μ = 5–100%). Pseudomonas sp. strain 2 and Stenotrophomonas sp. moderately to strongly inhibited all six Batrachochytrium genotypes at both temperatures (μ = 57–100%). All bacteria consistently inhibited B. salamandrivorans. Using cluster analysis of inhibition scores, we found that more closely related Batrachochytrium genotypes grouped together, suggesting that bacterial inhibition strength may be predictable based on Batrachochytrium relatedness. We conclude that bacterial inhibition capabilities change among bacterial strains, Batrachochytrium genotypes and temperatures. A comprehensive understanding of bacterial inhibitory function, across pathogen genotypes and temperatures, is needed to better predict the role of bacterial symbionts in amphibian disease ecology. For targeted conservation applications, we recommend using bacterial strains identified as strongly inhibitory as they are most likely to produce broad-spectrum antimicrobial agents at a range of temperatures.
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Affiliation(s)
- Carly R Muletz-Wolz
- Department of Biology, University of Maryland, College ParkMD, United States.,Center for Conservation Genomics, Smithsonian Conservation Biology Institute, National Zoological Park, WashingtonDC, United States
| | - Jose G Almario
- Department of Biology, University of Maryland, College ParkMD, United States
| | - Samuel E Barnett
- Department of Biology, University of Maryland, College ParkMD, United States.,Department of Microbiology, Cornell University, IthacaNY, United States
| | - Graziella V DiRenzo
- Department of Biology, University of Maryland, College ParkMD, United States.,Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa BarbaraCA, United States
| | - An Martel
- Department of Pathology, Bacteriology and Poultry Diseases, Ghent UniversityGhent, Belgium
| | - Frank Pasmans
- Department of Pathology, Bacteriology and Poultry Diseases, Ghent UniversityGhent, Belgium
| | - Kelly R Zamudio
- Department of Ecology and Evolutionary Biology, Cornell University, IthacaNY, United States
| | - Luís Felipe Toledo
- Department of Animal Biology, State University of CampinasCampinas, Brazil
| | - Karen R Lips
- Department of Biology, University of Maryland, College ParkMD, United States
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47
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Steenwyk J, Rokas A. Extensive Copy Number Variation in Fermentation-Related Genes Among Saccharomyces cerevisiae Wine Strains. G3 (BETHESDA, MD.) 2017; 7:1475-1485. [PMID: 28292787 PMCID: PMC5427499 DOI: 10.1534/g3.117.040105] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 03/08/2017] [Indexed: 01/30/2023]
Abstract
Due to the importance of Saccharomyces cerevisiae in wine-making, the genomic variation of wine yeast strains has been extensively studied. One of the major insights stemming from these studies is that wine yeast strains harbor low levels of genetic diversity in the form of single nucleotide polymorphisms (SNPs). Genomic structural variants, such as copy number (CN) variants, are another major type of variation segregating in natural populations. To test whether genetic diversity in CN variation is also low across wine yeast strains, we examined genome-wide levels of CN variation in 132 whole-genome sequences of S. cerevisiae wine strains. We found an average of 97.8 CN variable regions (CNVRs) affecting ∼4% of the genome per strain. Using two different measures of CN diversity, we found that gene families involved in fermentation-related processes such as copper resistance (CUP), flocculation (FLO), and glucose metabolism (HXT), as well as the SNO gene family whose members are expressed before or during the diauxic shift, showed substantial CN diversity across the 132 strains examined. Importantly, these same gene families have been shown, through comparative transcriptomic and functional assays, to be associated with adaptation to the wine fermentation environment. Our results suggest that CN variation is a substantial contributor to the genomic diversity of wine yeast strains, and identify several candidate loci whose levels of CN variation may affect the adaptation and performance of wine yeast strains during fermentation.
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Affiliation(s)
- Jacob Steenwyk
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235
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48
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Chytrid fungus infection in zebrafish demonstrates that the pathogen can parasitize non-amphibian vertebrate hosts. Nat Commun 2017; 8:15048. [PMID: 28425465 PMCID: PMC5411484 DOI: 10.1038/ncomms15048] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 02/23/2017] [Indexed: 01/07/2023] Open
Abstract
Aquatic chytrid fungi threaten amphibian biodiversity worldwide owing to their ability to rapidly expand their geographical distributions and to infect a wide range of hosts. Combating this risk requires an understanding of chytrid host range to identify potential reservoirs of infection and to safeguard uninfected regions through enhanced biosecurity. Here we extend our knowledge on the host range of the chytrid Batrachochytrium dendrobatidis by demonstrating infection of a non-amphibian vertebrate host, the zebrafish. We observe dose-dependent mortality and show that chytrid can infect and proliferate on zebrafish tissue. We also show that infection phenotypes (fin erosion, cell apoptosis and muscle degeneration) are direct symptoms of infection. Successful infection is dependent on disrupting the zebrafish microbiome, highlighting that, as is widely found in amphibians, commensal bacteria confer protection against this pathogen. Collectively, our findings greatly expand the limited tool kit available to study pathogenesis and host response to chytrid infection.
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49
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Becker C, Greenspan S, Tracy K, Dash J, Lambertini C, Jenkinson T, Leite D, Toledo L, Longcore J, James T, Zamudio K. Variation in phenotype and virulence among enzootic and panzootic amphibian chytrid lineages. FUNGAL ECOL 2017. [DOI: 10.1016/j.funeco.2016.11.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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50
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Farrer RA, Martel A, Verbrugghe E, Abouelleil A, Ducatelle R, Longcore JE, James TY, Pasmans F, Fisher MC, Cuomo CA. Genomic innovations linked to infection strategies across emerging pathogenic chytrid fungi. Nat Commun 2017; 8:14742. [PMID: 28322291 PMCID: PMC5364385 DOI: 10.1038/ncomms14742] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 01/26/2017] [Indexed: 11/09/2022] Open
Abstract
To understand the evolutionary pathways that lead to emerging infections of vertebrates, here we explore the genomic innovations that allow free-living chytrid fungi to adapt to and colonize amphibian hosts. Sequencing and comparing the genomes of two pathogenic species of Batrachochytrium to those of close saprophytic relatives reveals that pathogenicity is associated with remarkable expansions of protease and cell wall gene families, while divergent infection strategies are linked to radiations of lineage-specific gene families. By comparing the host–pathogen response to infection for both pathogens, we illuminate the traits that underpin a strikingly different immune response within a shared host species. Our results show that, despite commonalities that promote infection, specific gene-family radiations contribute to distinct infection strategies. The breadth and evolutionary novelty of candidate virulence factors that we discover underscores the urgent need to halt the advance of pathogenic chytrids and prevent incipient loss of biodiversity. Batrachochytrium dendrobatidis and B. salamandrivorans are both important pathogens of amphibians, but they differ in their host ranges, infection strategies, and host immune responses. Here, Farrer and colleagues compare their genomes and transcriptomes to identify the genetic basis of these differences.
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Affiliation(s)
- Rhys A Farrer
- Genome Sequencing and Analysis Program, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA.,Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London W2 1PG, UK
| | - An Martel
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium
| | - Elin Verbrugghe
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium
| | - Amr Abouelleil
- Genome Sequencing and Analysis Program, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Richard Ducatelle
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium
| | - Joyce E Longcore
- School of Biology and Ecology, University of Maine, Orono, Maine 04469, USA
| | - Timothy Y James
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Frank Pasmans
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium
| | - Matthew C Fisher
- Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London W2 1PG, UK
| | - Christina A Cuomo
- Genome Sequencing and Analysis Program, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
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