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Hicks RH, Moreno-Beltrán M, Gore-Lloyd D, Chuck CJ, Henk DA. The Oleaginous Yeast Metschnikowia pulcherrima Displays Killer Activity against Avian-Derived Pathogenic Bacteria. Biology (Basel) 2021; 10:biology10121227. [PMID: 34943142 PMCID: PMC8698481 DOI: 10.3390/biology10121227] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/11/2021] [Accepted: 11/19/2021] [Indexed: 02/07/2023]
Abstract
Simple Summary Pathogenic bacteria in poultry and the widespread use of antibiotics to manage them are costly in terms of production, environmental risk and human health. Probiotic and other low-cost, non-antibiotic treatments offer attractive alternatives to antibiotic applications, but relatively few of these options exist. In this research, we investigated the potential of an otherwise-useful industrial yeast, Metschnikowia pulcherrima, for the active suppression of poultry pathogenic bacteria. We tested multiple strains of yeast against several important bacterial pathogens and found that the more inhibitory strains of yeast supressed bacterial growth and actively killed the most recalcitrant bacteria. Less aggressive yeast strains could increase the growth of some bacterial strains in some environments. The yeast produced novel molecules in response to the presence of the bacteria and we identified several potential mechanisms by which the yeast inhibited or killed bacteria. Together, these results point towards a useful application of a novel yeast for enhanced, antibiotic-free pathogen control. Abstract Metschnikowia pulcherrima is a non-conventional yeast with potential to be used in biotechnological processes, especially those involving low-cost feedstock exploitation and biocontrol applications. The combination of traits that supports these industrial applications in M. pulcherrima also makes it an attractive option to study in the context of livestock health. In this study, we examined the specific interactions between M. pulcherrima and multiple avian pathogenic bacteria. We tested individual bacteria–yeast interactions and bacterial combinations in both solid and liquid media and in variable nutrient environments. Across multiple isolates of M. pulcherrima, we observed different levels of antimicrobial activity, varying from supporting the growth of competing bacteria through suppression and bacterial killing, and we found that these responses varied depending on the bacterial strains and media. We identified multiple molecular routes, including proteins produced by M. pulcherrima strains, that acted to control these microbial interactions. Furthermore, protein screening revealed that M. pulcherrima strains were induced to produce proteins specifically when exposed to bacterial strains, suggesting that fine-tuned mechanisms allow M. pulcherrima to function as a potential lynchpin in a microbial community.
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Affiliation(s)
- Robert H. Hicks
- Milner Centre for Evolution, University of Bath, Bath BA2 7AY, UK; (R.H.H.); (M.M.-B.); (D.G.-L.)
| | - Mauro Moreno-Beltrán
- Milner Centre for Evolution, University of Bath, Bath BA2 7AY, UK; (R.H.H.); (M.M.-B.); (D.G.-L.)
| | - Deborah Gore-Lloyd
- Milner Centre for Evolution, University of Bath, Bath BA2 7AY, UK; (R.H.H.); (M.M.-B.); (D.G.-L.)
| | | | - Daniel A. Henk
- Milner Centre for Evolution, University of Bath, Bath BA2 7AY, UK; (R.H.H.); (M.M.-B.); (D.G.-L.)
- Correspondence:
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Abeln F, Hicks RH, Auta H, Moreno-Beltrán M, Longanesi L, Henk DA, Chuck CJ. Semi-continuous pilot-scale microbial oil production with Metschnikowia pulcherrima on starch hydrolysate. Biotechnol Biofuels 2020; 13:127. [PMID: 32695223 PMCID: PMC7367368 DOI: 10.1186/s13068-020-01756-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 06/23/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Heterotrophic microbial oils are potentially a more sustainable alternative to vegetable or fossil oils for food and fuel applications. However, as almost all work in the area is conducted on the laboratory scale, such studies carry limited industrial relevance and do not give a clear indication of what is required to produce an actual industrial process. Metschnikowia pulcherrima is a non-pathogenic industrially promising oleaginous yeast which exhibits numerous advantages for cost-effective lipid production, including a wide substrate uptake, antimicrobial activity and fermentation inhibitor tolerance. In this study, M. pulcherrima was fermented in stirred tank reactors of up to 350 L with 250-L working volume in both batch and semi-continuous operation to highlight the potential industrial relevance. Due to being food-grade, suitable for handling at scale and to demonstrate the oligosaccharide uptake capacity of M. pulcherrima, enzyme-hydrolysed starch in the form of glucose syrup was selected as fermentation feedstock. RESULTS In batch fermentations on the 2-L scale, a lipid concentration of 14.6 g L-1 and productivity of 0.11 g L-1 h-1 were achieved, which was confirmed at 50 L (15.8 g L-1; 0.10 g L-1 h-1). The maximum lipid production rate was 0.33 g L-1 h-1 (daily average), but the substrate uptake rate decreased with oligosaccharide chain length. To produce 1 kg of dry yeast biomass containing up to 43% (w/w) lipids, 5.2 kg of the glucose syrup was required, with a lipid yield of up to 0.21 g g-1 consumed saccharides. In semi-continuous operation, for the first time, an oleaginous yeast was cultured for over 2 months with a relatively stable lipid production rate (around 0.08 g L-1 h-1) and fatty acid profile (degree of fatty acid saturation around 27.6% w/w), and without contamination. On the 250-L scale, comparable results were observed, culminating in the generation of nearly 10 kg lipids with a lipid productivity of 0.10 g L-1 h-1. CONCLUSIONS The results establish the importance of M. pulcherrima for industrial biotechnology and its suitability to commercially produce a food-grade oil. Further improvements in the productivity are required to make M. pulcherrima lipid production industrial reality, particularly when longer-chain saccharides are involved.
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Affiliation(s)
- Felix Abeln
- Centre for Sustainable and Circular Technologies, University of Bath, Bath, UK
- Department of Chemical Engineering, University of Bath, Bath, UK
| | - Robert H. Hicks
- Department of Biology & Biochemistry, University of Bath, Bath, UK
| | - Hadiza Auta
- Department of Chemical Engineering, University of Bath, Bath, UK
| | | | - Luca Longanesi
- Department of Chemical Engineering, University of Bath, Bath, UK
| | - Daniel A. Henk
- Department of Biology & Biochemistry, University of Bath, Bath, UK
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Hicks RH, Chuck CJ, Scott RJ, Leak DJ, Henk DA. Comparison of Nile Red and Cell Size Analysis for High‐Throughput Lipid Estimation Within Oleaginous Yeast. EUR J LIPID SCI TECH 2019. [DOI: 10.1002/ejlt.201800355] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Robert H. Hicks
- Centre for Doctoral Training in Sustainable Chemical TechnologiesDepartment of Biology and BiochemistryUniversity of Bath Bath BA2 7AY United Kingdom
| | - Christopher J. Chuck
- Department of Chemical EngineeringUniversity of Bath Bath BA2 7AY United Kingdom
| | - Roderick J. Scott
- Department of Biology and BiochemistryUniversity of Bath Bath BA2 7AY United Kingdom
| | - David J. Leak
- Department of Biology and BiochemistryUniversity of Bath Bath BA2 7AY United Kingdom
| | - Daniel A. Henk
- Department of Biology and BiochemistryUniversity of Bath Bath BA2 7AY United Kingdom
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Abeln F, Fan J, Budarin VL, Briers H, Parsons S, Allen MJ, Henk DA, Clark J, Chuck CJ. Lipid production through the single-step microwave hydrolysis of macroalgae using the oleaginous yeast Metschnikowia pulcherrima. ALGAL RES 2019. [DOI: 10.1016/j.algal.2019.101411] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Affiliation(s)
- Meredith Blackwell
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803
| | - Daniel A. Henk
- Biology Department, Duke University, Box 90338, Durham, North Carolina 27708
| | - Kevin G. Jones
- Department of Biology, University of Virginia at Wise, Wise, Virginia 24293
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Henk DA, Weir A, Blackwell M. Laboulbeniopsis termitarius, an ectoparasite of termites newly recognized as a member of the Laboulbeniomycetes. Mycologia 2017; 95:561-4. [DOI: 10.1080/15572536.2004.11833059] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Daniel A. Henk
- Biology Department, Duke University, Box 90338, Durham, North Carolina 27708
| | - Alex Weir
- Faculty of Environmental and Forest Biology, SUNY College of Environmental Science and Forestry, 350 Illick Hall, 1 Forestry Drive, Syracuse, New York 13210
| | - Meredith Blackwell
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803
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Affiliation(s)
- Daniel A. Henk
- Department of Biology, Duke University, CB 90338, Durham, North Carolina 27708
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Aime MC, Matheny PB, Henk DA, Frieders EM, Nilsson RH, Piepenbring M, McLaughlin DJ, Szabo LJ, Begerow D, Sampaio JP, Bauer R, Weiß M, Oberwinkler F, Hibbett D. An overview of the higher level classification of Pucciniomycotina based on combined analyses of nuclear large and small subunit rDNA sequences. Mycologia 2017. [DOI: 10.1080/15572536.2006.11832619] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- M. Catherine Aime
- USDA-ARS, Systematic Botany and Mycology Lab, Beltsville, Maryland 20705
| | | | - Daniel A. Henk
- USDA-ARS, Systematic Botany and Mycology Lab, Beltsville, Maryland 20705
| | | | - R. Henrik Nilsson
- Göteborg University, Department of Plant and Environmental Sciences, Göteborg, Sweden
| | - Meike Piepenbring
- J.W. Goethe-Universität Frankfurt, Department of Mycology, Frankfurt, Germany
| | - David J. McLaughlin
- Department of Plant Biology, University of Minnesota, St Paul, Minnesota 55108
| | - Les J. Szabo
- USDA-ARS, Cereal Disease Lab, University of Minnesota, St Paul, Minnesota 55108
| | - Dominik Begerow
- Universität Tübingen, Spezielle Botanik und Mykologie, Tübingen, Germany
| | - José Paulo Sampaio
- CREM, SABT, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | | | | | - Franz Oberwinkler
- Universität Tübingen, Spezielle Botanik und Mykologie, Tübingen, Germany
| | - David Hibbett
- Biology Department, Clark University, Worcester, Massachusetts 01610
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Arnold AE, Henk DA, Eells RL, Lutzoni F, Vilgalys R. Diversity and phylogenetic affinities of foliar fungal endophytes in loblolly pine inferred by culturing and environmental PCR. Mycologia 2017. [DOI: 10.1080/15572536.2007.11832578] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
| | | | | | | | - Rytas Vilgalys
- Department of Biology, Duke University, Durham, North Carolina 27708
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Farrer RA, Voelz K, Henk DA, Johnston SA, Fisher MC, May RC, Cuomo CA. Microevolutionary traits and comparative population genomics of the emerging pathogenic fungus Cryptococcus gattii. Philos Trans R Soc Lond B Biol Sci 2016; 371:20160021. [PMID: 28080992 PMCID: PMC5095545 DOI: 10.1098/rstb.2016.0021] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2016] [Indexed: 01/15/2023] Open
Abstract
Emerging fungal pathogens cause an expanding burden of disease across the animal kingdom, including a rise in morbidity and mortality in humans. Yet, we currently have only a limited repertoire of available therapeutic interventions. A greater understanding of the mechanisms of fungal virulence and of the emergence of hypervirulence within species is therefore needed for new treatments and mitigation efforts. For example, over the past decade, an unusual lineage of Cryptococcus gattii, which was first detected on Vancouver Island, has spread to the Canadian mainland and the Pacific Northwest infecting otherwise healthy individuals. The molecular changes that led to the development of this hypervirulent cryptococcal lineage remain unclear. To explore this, we traced the history of similar microevolutionary events that can lead to changes in host range and pathogenicity. Here, we detail fine-resolution mapping of genetic differences between two highly related Cryptococcus gattii VGIIc isolates that differ in their virulence traits (phagocytosis, vomocytosis, macrophage death, mitochondrial tubularization and intracellular proliferation). We identified a small number of single site variants within coding regions that potentially contribute to variations in virulence. We then extended our methods across multiple lineages of C. gattii to study how selection is acting on key virulence genes within different lineages.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)
- Rhys A Farrer
- Genome Sequencing and Analysis Program, The Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London W2 1PG, UK
| | - Kerstin Voelz
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
- NIHR Surgical Reconstruction and Microbiology Research Centre, University Hospitals Birmingham NHS Foundation Trust, Queen Elizabeth Hospital Birmingham, Birmingham B15 2TH, UK
| | - Daniel A Henk
- Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London W2 1PG, UK
| | - Simon A Johnston
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Matthew C Fisher
- Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London W2 1PG, UK
| | - Robin C May
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
- NIHR Surgical Reconstruction and Microbiology Research Centre, University Hospitals Birmingham NHS Foundation Trust, Queen Elizabeth Hospital Birmingham, Birmingham B15 2TH, UK
| | - Christina A Cuomo
- Genome Sequencing and Analysis Program, The Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
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Gómez LD, Henk DA. Validation of the species of Septobasidium (Basidiomycetes) described by John N. Couch. Lankesteriana 2016. [DOI: 10.15517/lank.v4i1.22985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
<div class="page" title="Page 1"><div class="section"><div class="layoutArea"><div class="column"><p><span>Aquí se validan póstumamente los nombres de especies y variedades nuevas descritas por J.N. Couch en su monografía de </span><span>Septobasidium </span><span>(1938); se incluyen los propuestos antes por otros autores, que no eran válidos por faltar una descripción latina. Se proveen traducciones al latín de las descripciones ingle- sas de Couch y se designan holotipos, algunos isotipos y paratipos, un neotipo y un isoneotipo. </span></p></div></div></div></div>
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Voelz K, Ma H, Phadke S, Byrnes EJ, Zhu P, Mueller O, Farrer RA, Henk DA, Lewit Y, Hsueh YP, Fisher MC, Idnurm A, Heitman J, May RC. Transmission of Hypervirulence traits via sexual reproduction within and between lineages of the human fungal pathogen cryptococcus gattii. PLoS Genet 2013; 9:e1003771. [PMID: 24039607 PMCID: PMC3764205 DOI: 10.1371/journal.pgen.1003771] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 07/22/2013] [Indexed: 01/11/2023] Open
Abstract
Since 1999 a lineage of the pathogen Cryptococcus gattii has been infecting humans and other animals in Canada and the Pacific Northwest of the USA. It is now the largest outbreak of a life-threatening fungal infection in a healthy population in recorded history. The high virulence of outbreak strains is closely linked to the ability of the pathogen to undergo rapid mitochondrial tubularisation and proliferation following engulfment by host phagocytes. Most outbreaks spread by geographic expansion across suitable niches, but it is known that genetic re-assortment and hybridisation can also lead to rapid range and host expansion. In the context of C. gattii, however, the likelihood of virulence traits associated with the outbreak lineages spreading to other lineages via genetic exchange is currently unknown. Here we address this question by conducting outgroup crosses between distantly related C. gattii lineages (VGII and VGIII) and ingroup crosses between isolates from the same molecular type (VGII). Systematic phenotypic characterisation shows that virulence traits are transmitted to outgroups infrequently, but readily inherited during ingroup crosses. In addition, we observed higher levels of biparental (as opposed to uniparental) mitochondrial inheritance during VGII ingroup sexual mating in this species and provide evidence for mitochondrial recombination following mating. Taken together, our data suggest that hypervirulence can spread among the C. gattii lineages VGII and VGIII, potentially creating novel hypervirulent genotypes, and that current models of uniparental mitochondrial inheritance in the Cryptococcus genus may not be universal. How infections spread within the human population is an important question in forecasting potential epidemics. One way to investigate potential mechanisms is to test experimentally whether combinations of genes that confer high virulence are able to spread to less-virulent lineages. Here, we address this question in a fungal pathogen that is causing an outbreak of meningitis in healthy humans in Canada and the Pacific Northwest. We demonstrate that virulence traits are easily transmitted between closely related pathogenic strains, but are more difficult to transmit to more distant lineages. In addition, we show that a paradigm of organelle inheritance, namely that mitochondria are inherited uniparentally from the a mating type, is altered in the R265α outbreak strain such that it transmits its mitochondrial genome to 25–30% of its progeny. This biparental inheritance likely contributes to increased mitochondrial recombination. Taken together, our data suggest that virulence traits may be relatively mobile within this species and that current models of mitochondrial inheritance may require revising.
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Affiliation(s)
- Kerstin Voelz
- Institute of Microbiology and Infection & School of Biosciences, University of Birmingham, Birmingham, United Kingdom
- The National Institute of Health Research Surgical Reconstruction and Microbiology Research Centre, Queen Elizabeth Hospital Birmingham, Birmingham, United Kingdom
| | - Hansong Ma
- Institute of Microbiology and Infection & School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Sujal Phadke
- Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, United States of America
| | - Edmond J. Byrnes
- Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, United States of America
| | - Pinkuan Zhu
- School of Biological Sciences, University of Missouri, Kansas City, Missouri, United States of America
| | - Olaf Mueller
- Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, United States of America
| | - Rhys A. Farrer
- Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom
| | - Daniel A. Henk
- Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom
| | - Yonathan Lewit
- Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, United States of America
| | - Yen-Ping Hsueh
- Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, United States of America
| | - Matthew C. Fisher
- Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom
| | - Alexander Idnurm
- School of Biological Sciences, University of Missouri, Kansas City, Missouri, United States of America
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, United States of America
- * E-mail: (JH); (RCM)
| | - Robin C. May
- Institute of Microbiology and Infection & School of Biosciences, University of Birmingham, Birmingham, United Kingdom
- The National Institute of Health Research Surgical Reconstruction and Microbiology Research Centre, Queen Elizabeth Hospital Birmingham, Birmingham, United Kingdom
- * E-mail: (JH); (RCM)
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Farrer RA, Henk DA, MacLean D, Studholme DJ, Fisher MC. Using false discovery rates to benchmark SNP-callers in next-generation sequencing projects. Sci Rep 2013; 3:1512. [PMID: 23518929 PMCID: PMC3604800 DOI: 10.1038/srep01512] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 02/25/2013] [Indexed: 12/16/2022] Open
Abstract
Sequence alignments form the basis for many comparative and population genomic studies. Alignment tools provide a range of accuracies dependent on the divergence between the sequences and the alignment methods. Despite widespread use, there is no standard method for assessing the accuracy of a dataset and alignment strategy after resequencing. We present a framework and tool for determining the overall accuracies of an input read dataset, alignment and SNP-calling method providing an isolate in that dataset has a corresponding, or closely related reference sequence available. In addition to this tool for comparing False Discovery Rates (FDR), we include a method for determining homozygous and heterozygous positions from an alignment using binomial probabilities for an expected error rate. We benchmark this method against other SNP callers using our FDR method with three fungal genomes, finding that it was able achieve a high level of accuracy. These tools are available at http://cfdr.sourceforge.net/.
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Affiliation(s)
- Rhys A Farrer
- Department of Infectious Disease Epidemiology, St Mary's Hospital, Imperial College London, London, UK.
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Henk DA, Shahar-Golan R, Devi KR, Boyce KJ, Zhan N, Fedorova ND, Nierman WC, Hsueh PR, Yuen KY, Sieu TPM, Kinh NV, Wertheim H, Baker SG, Day JN, Vanittanakom N, Bignell EM, Andrianopoulos A, Fisher MC. Clonality despite sex: the evolution of host-associated sexual neighborhoods in the pathogenic fungus Penicillium marneffei. PLoS Pathog 2012; 8:e1002851. [PMID: 23055919 PMCID: PMC3464222 DOI: 10.1371/journal.ppat.1002851] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Accepted: 06/25/2012] [Indexed: 12/04/2022] Open
Abstract
Molecular genetic approaches typically detect recombination in microbes regardless of assumed asexuality. However, genetic data have shown the AIDS-associated pathogen Penicillium marneffei to have extensive spatial genetic structure at local and regional scales, and although there has been some genetic evidence that a sexual cycle is possible, this haploid fungus is thought to be genetically, as well as morphologically, asexual in nature because of its highly clonal population structure. Here we use comparative genomics, experimental mixed-genotype infections, and population genetic data to elucidate the role of recombination in natural populations of P. marneffei. Genome wide comparisons reveal that all the genes required for meiosis are present in P. marneffei, mating type genes are arranged in a similar manner to that found in other heterothallic fungi, and there is evidence of a putatively meiosis-specific mutational process. Experiments suggest that recombination between isolates of compatible mating types may occur during mammal infection. Population genetic data from 34 isolates from bamboo rats in India, Thailand and Vietnam, and 273 isolates from humans in China, India, Thailand, and Vietnam show that recombination is most likely to occur across spatially and genetically limited distances in natural populations resulting in highly clonal population structure yet sexually reproducing populations. Predicted distributions of three different spatial genetic clusters within P. marneffei overlap with three different bamboo rat host distributions suggesting that recombination within hosts may act to maintain population barriers within P. marneffei.
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Affiliation(s)
- Daniel A Henk
- Department of Infectious Disease Epidemiology, Imperial College, Norfolk Place, London, United Kingdom.
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Abstract
Throughout the eukaryotes, sexual reproduction is an almost universal phenomenon. However, within the Kingdom Fungi, this relationship is not so clear-cut. Fungi exhibit a spectrum of reproductive modes and life-cycles; amongst the better known species, sexual reproduction is often facultative, can be rare, and in over half of the known Ascomycota (the moulds) is unknown (Taylor et al. 1999). However, over the last decade, it has become apparent that many of these asexual mitosporic taxa undergo cryptic recombination via unobserved mechanisms and that wholly asexual fungi are, in fact, a rarity (Taylor et al. 1999, 2001; Heitman 2010). This revolution in our understanding of fungal sexuality has come about in two ways: Firstly, sexual reproduction leaves an imprint on fungal genomes by maintaining genes required for mating and by generating patterns of mutation and recombination restricted to meiotic processes. Secondly, scientists have become better at catching fungi in flagrante delicto. The genus Aspergillus is one such fungus where a combination of population genetics, genomics and taxonomy has been able to intuit the existence of sex, then to catch the fungus in the act and formally describe their sexual stages. So, why are sexy moulds exciting? One species in particular, Aspergillus flavus, is notorious for its ability to produce a diverse array of secondary metabolites, of which the polyketide aflatoxins (AF) are carcinogenic and others (such as cyclopiazonic acid) are toxigenic. Because of the predilection of A. flavus to grow on crops, such as peanuts, corn and cotton, biocontrol is widely used to mitigate infection by pre-applying nonaflatoxigenic (AF-) strains to competitively exclude the wild-type AF+ strains. However, the eventual fate in nature of these biocontrol strains is not known. In this issue of Molecular Ecology, Olarte et al. (2012) make an important contribution by using laboratory crosses of A. flavus to show that not only is AF highly heritable, but AF- strains can become AF+ via crossing over during meiosis. This observation has raised the spectre of cross-breeding and non-mendelian inheritance of AF between native and biocontrol strains of the fungus, leading to an increase in the natural diversity of the fungus with perhaps unanticipated consequences.
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Affiliation(s)
- Matthew C Fisher
- Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College London, London, UK.
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Fisher MC, Henk DA, Briggs CJ, Brownstein JS, Madoff LC, McCraw SL, Gurr SJ. Emerging fungal threats to animal, plant and ecosystem health. Nature 2012; 484:186-94. [PMID: 22498624 PMCID: PMC3821985 DOI: 10.1038/nature10947] [Citation(s) in RCA: 1719] [Impact Index Per Article: 143.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 01/25/2012] [Indexed: 01/15/2023]
Abstract
The past two decades have seen an increasing number of virulent infectious diseases in natural populations and managed landscapes. In both animals and plants, an unprecedented number of fungal and fungal-like diseases have recently caused some of the most severe die-offs and extinctions ever witnessed in wild species, and are jeopardizing food security. Human activity is intensifying fungal disease dispersal by modifying natural environments and thus creating new opportunities for evolution. We argue that nascent fungal infections will cause increasing attrition of biodiversity, with wider implications for human and ecosystem health, unless steps are taken to tighten biosecurity worldwide.
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Affiliation(s)
- Matthew C Fisher
- Department of Infectious Disease Epidemiology, Imperial College, London W2 1PG, UK.
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Henk DA, Fisher MC. The gut fungus Basidiobolus ranarum has a large genome and different copy numbers of putatively functionally redundant elongation factor genes. PLoS One 2012; 7:e31268. [PMID: 22363602 PMCID: PMC3281927 DOI: 10.1371/journal.pone.0031268] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Accepted: 01/05/2012] [Indexed: 12/16/2022] Open
Abstract
Fungal genomes range in size from 2.3 Mb for the microsporidian Encephalitozoon intestinalis up to 8000 Mb for Entomophaga aulicae, with a mean genome size of 37 Mb. Basidiobolus, a common inhabitant of vertebrate guts, is distantly related to all other fungi, and is unique in possessing both EF-1α and EFL genes. Using DNA sequencing and a quantitative PCR approach, we estimated a haploid genome size for Basidiobolus at 350 Mb. However, based on allelic variation, the nuclear genome is at least diploid, leading us to believe that the final genome size is at least 700 Mb. We also found that EFL was in three times the copy number of its putatively functionally overlapping paralog EF-1α. This suggests that gene or genome duplication may be an important feature of B. ranarum evolution, and also suggests that B. ranarum may have mechanisms in place that favor the preservation of functionally overlapping genes.
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Affiliation(s)
- Daniel A Henk
- The Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom.
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Farrer RA, Weinert LA, Bielby J, Garner TWJ, Balloux F, Clare F, Bosch J, Cunningham AA, Weldon C, du Preez LH, Anderson L, Pond SLK, Shahar-Golan R, Henk DA, Fisher MC. Multiple emergences of genetically diverse amphibian-infecting chytrids include a globalized hypervirulent recombinant lineage. Proc Natl Acad Sci U S A 2011; 108:18732-6. [PMID: 22065772 PMCID: PMC3219125 DOI: 10.1073/pnas.1111915108] [Citation(s) in RCA: 298] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Batrachochytrium dendrobatidis (Bd) is a globally ubiquitous fungal infection that has emerged to become a primary driver of amphibian biodiversity loss. Despite widespread effort to understand the emergence of this panzootic, the origins of the infection, its patterns of global spread, and principle mode of evolution remain largely unknown. Using comparative population genomics, we discovered three deeply diverged lineages of Bd associated with amphibians. Two of these lineages were found in multiple continents and are associated with known introductions by the amphibian trade. We found that isolates belonging to one clade, the global panzootic lineage (BdGPL) have emerged across at least five continents during the 20th century and are associated with the onset of epizootics in North America, Central America, the Caribbean, Australia, and Europe. The two newly identified divergent lineages, Cape lineage (BdCAPE) and Swiss lineage (BdCH), were found to differ in morphological traits when compared against one another and BdGPL, and we show that BdGPL is hypervirulent. BdGPL uniquely bears the hallmarks of genomic recombination, manifested as extensive intergenomic phylogenetic conflict and patchily distributed heterozygosity. We postulate that contact between previously genetically isolated allopatric populations of Bd may have allowed recombination to occur, resulting in the generation, spread, and invasion of the hypervirulent BdGPL leading to contemporary disease-driven losses in amphibian biodiversity.
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Affiliation(s)
- Rhys A Farrer
- Department Infectious Disease Epidemiology, Imperial College, London W2 1PG, United Kingdom.
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Henk DA, Eagle CE, Brown K, Van Den Berg MA, Dyer PS, Peterson SW, Fisher MC. Speciation despite globally overlapping distributions in Penicillium chrysogenum: the population genetics of Alexander Fleming's lucky fungus. Mol Ecol 2011; 20:4288-301. [PMID: 21951491 DOI: 10.1111/j.1365-294x.2011.05244.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Eighty years ago, Alexander Fleming described the antibiotic effects of a fungus that had contaminated his bacterial culture, kick starting the antimicrobial revolution. The fungus was later ascribed to a putatively globally distributed asexual species, Penicillium chrysogenum. Recently, the species has been shown to be genetically diverse, and possess mating-type genes. Here, phylogenetic and population genetic analyses show that this apparently ubiquitous fungus is actually composed of at least two genetically distinct species with only slight differences detected in physiology. We found each species in air and dust samples collected in and around St Mary's Hospital where Fleming worked. Genotyping of 30 markers across the genome showed that preserved fungal material from Fleming's laboratory was nearly identical to derived strains currently in culture collections and in the same distinct species as a wild progenitor strain of current penicillin producing industrial strains rather than the type species P. chrysogenum. Global samples of the two most common species were found to possess mating-type genes in a near 1:1 ratio, and show evidence of recombination with little geographic population subdivision evident. However, no hybridization was detected between the species despite an estimated time of divergence of less than 1MYA. Growth studies showed significant interspecific inhibition by P. chrysogenum of the other common species, suggesting that competition may facilitate species maintenance despite globally overlapping distributions. Results highlight under-recognized diversity even among the best-known fungal groups and the potential for speciation despite overlapping distribution.
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Affiliation(s)
- D A Henk
- Department of Infectious Disease Epidemiology, Imperial College Faculty of Medicine, St Mary's Campus, Norfolk Place, London W2 1PG, UK.
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Abstract
Penicillium dipodomyis is thought to be an exclusively asexual fungus associated with Kangaroo Rats, Dipodomys species, and is unique among Penicillium species in growing at 37°C but producing no known toxins. Lack of recombination within P. dipodomyis would result in limited adaptive flexibility but possibly enhance local adaptation and host selection via maintenance of favourable genotypes. Here, analysis of DNA sequence data from five protein-coding genes shows that recombination occurs within P. dipodomyis on a small spatial scale. Furthermore, detection of mating-type alleles supports outcrossing and a sexual cycle in P. dipodomyis. P. dipodomyis was a weaker competitor in in vitro assays with other Penicillium species found in association with Kanagaroo rats. Bayesian species level analysis suggests that the P. dipodomyis lineage diverged from closely related species also found in cheek pouches of Kangaroo Rats and their stored seeds about 11 million years ago, a similar divergence time as Dipodomys from its sister rodent taxa.
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Affiliation(s)
- Daniel A Henk
- Department of Infectious Disease Epidemiology, Imperial College, London, United Kingdom.
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Cao C, Liang L, Wang W, Luo H, Huang S, Liu D, Xu J, Henk DA, Fisher MC. Common reservoirs for Penicillium marneffei infection in humans and rodents, China. Emerg Infect Dis 2011; 17:209-14. [PMID: 21291590 PMCID: PMC3204759 DOI: 10.3201/eid1702.100718] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Human penicilliosis marneffei is an emerging infectious disease caused by the fungus Penicillium marneffei. High prevalence of infection among bamboo rats of the genera Rhizomys and Cannomys suggest that these rodents are a key facet of the P. marneffei life cycle. We trapped bamboo rats during June 2004–July 2005 across Guangxi Province, China, and demonstrated 100% prevalence of infection. Multilocus genotypes show that P. marneffei isolates from humans are similar to those infecting rats and are in some cases identical. Comparison of our dataset with genotypes recovered from sites across Southeast Asia shows that the overriding component of genetic structure in P. marneffei is spatial, with humans containing a greater diversity of genotypes than rodents. Humans and bamboo rats are sampling an as-yet undiscovered common reservoir of infection, or bamboo rats are a vector for human infections by acting as amplifiers of infectious dispersal stages.
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Affiliation(s)
- Cunwei Cao
- The First Affiliated Hospital of Guangxi Medical University, Nanning, People's Republic of China
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Simwami SP, Khayhan K, Henk DA, Aanensen DM, Boekhout T, Hagen F, Brouwer AE, Harrison TS, Donnelly CA, Fisher MC. Low diversity Cryptococcus neoformans variety grubii multilocus sequence types from Thailand are consistent with an ancestral African origin. PLoS Pathog 2011; 7:e1001343. [PMID: 21573144 PMCID: PMC3089418 DOI: 10.1371/journal.ppat.1001343] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Accepted: 04/15/2011] [Indexed: 12/19/2022] Open
Abstract
The global burden of HIV-associated cryptococcal meningitis is estimated at nearly one million cases per year, causing up to a third of all AIDS-related deaths. Molecular epidemiology constitutes the main methodology for understanding the factors underpinning the emergence of this understudied, yet increasingly important, group of pathogenic fungi. Cryptococcus species are notable in the degree that virulence differs amongst lineages, and highly-virulent emerging lineages are changing patterns of human disease both temporally and spatially. Cryptococcus neoformans variety grubii (Cng, serotype A) constitutes the most ubiquitous cause of cryptococcal meningitis worldwide, however patterns of molecular diversity are understudied across some regions experiencing significant burdens of disease. We compared 183 clinical and environmental isolates of Cng from one such region, Thailand, Southeast Asia, against a global MLST database of 77 Cng isolates. Population genetic analyses showed that Thailand isolates from 11 provinces were highly homogenous, consisting of the same genetic background (globally known as VNI) and exhibiting only ten nearly identical sequence types (STs), with three (STs 44, 45 and 46) dominating our sample. This population contains significantly less diversity when compared against the global population of Cng, specifically Africa. Genetic diversity in Cng was significantly subdivided at the continental level with nearly half (47%) of the global STs unique to a genetically diverse and recombining population in Botswana. These patterns of diversity, when combined with evidence from haplotypic networks and coalescent analyses of global populations, are highly suggestive of an expansion of the Cng VNI clade out of Africa, leading to a limited number of genotypes founding the Asian populations. Divergence time testing estimates the time to the most common ancestor between the African and Asian populations to be 6,920 years ago (95% HPD 122.96 - 27,177.76). Further high-density sampling of global Cng STs is now necessary to resolve the temporal sequence underlying the global emergence of this human pathogen.
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Affiliation(s)
- Sitali P. Simwami
- Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Kantarawee Khayhan
- CBS Fungal Biodiversity Centre, Utrecht, The Netherlands
- Department of Microbiology and Parasitology, School of Medical Science, Naresuan University Phayao, Phayao, Thailand
| | - Daniel A. Henk
- Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - David M. Aanensen
- Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Teun Boekhout
- CBS Fungal Biodiversity Centre, Utrecht, The Netherlands
| | - Ferry Hagen
- CBS Fungal Biodiversity Centre, Utrecht, The Netherlands
| | - Annemarie E. Brouwer
- Department of General Internal Medicine and Nijmegen University Center for Infectious Diseases, Radboud University Medical Centre, Nijmegen, The Netherlands
- St. Elisabeth Hospital, Tilburg, The Netherlands
| | - Thomas S. Harrison
- Department of Infectious Diseases, St George's Hospital Medical School, London, United Kingdom
| | - Christl A. Donnelly
- Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Matthew C. Fisher
- Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College London, London, United Kingdom
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Walker SF, Bosch J, Gomez V, Garner TWJ, Cunningham AA, Schmeller DS, Ninyerola M, Henk DA, Ginestet C, Arthur CP, Fisher MC. Factors driving pathogenicity vs. prevalence of amphibian panzootic chytridiomycosis in Iberia. Ecol Lett 2010; 13:372-82. [DOI: 10.1111/j.1461-0248.2009.01434.x] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Arnold AE, Henk DA, Eells RL, Lutzoni F, Vilgalys R. Diversity and phylogenetic affinities of foliar fungal endophytes in loblolly pine inferred by culturing and environmental PCR. Mycologia 2007; 99:185-206. [PMID: 17682771 DOI: 10.3852/mycologia.99.2.185] [Citation(s) in RCA: 190] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We examined endophytic fungi in asymptomatic foliage of loblolly pine (Pinus taeda) in North Carolina, U.S.A., with four goals: (i) to evaluate morphotaxa, BLAST matches and groups based on sequence similarity as functional taxonomic units; (ii) to explore methods to maximize phylogenetic signal for environmental datasets, which typically contain many taxa but few characters; (iii) to compare culturing vs. culture-free methods (environmental PCR of surface sterilized foliage) for estimating endophyte diversity and species composition; and (iv) to investigate the relationships between traditional ecological indices (e.g. Shannon index) and phylogenetic diversity (PD) in estimating endophyte diversity and spatial heterogeneity. Endophytes were recovered in culture from 87 of 90 P. taeda leaves sampled, yielding 439 isolates that represented 24 morphotaxa. Sequence data from the nuclear ribosomal internal transcribed spacer (ITS) for 150 isolates revealed 59 distinct ITS genotypes that represented 24 and 37 unique groups based on 90% and 95% sequence similarity, respectively. By recoding ambiguously aligned regions to extract phylogenetic signal and implementing a conservative phylogenetic backbone constraint, we recovered well supported phylogenies based on ca. 600 bp of the nuclear ribosomal large subunit (LSUrDNA) for 72 Ascomycota and Basidiomycota, 145 cultured endophytes and 33 environmental PCR samples. Comparisons with LSUrDNA-delimited species showed that morphotaxa adequately estimated total species richness but rarely corresponded to biologically meaningful groups. ITS BLAST results were variable in their utility, but ITS genotype groups based on 90% sequence similarity were concordant with LSUrDNA-delimited species. Environmental PCR yielded more genotypes per sampling effort and recovered several distinct clades relative to culturing, but some commonly cultured clades were never found (Sordariomycetes) or were rare relative to their high frequency among cultures (Leotiomycetes). In contrast to traditional indices, PD demonstrated spatial heterogeneity in endophyte assemblages among P. taeda trees and study plots. Our results highlight the need for caution in designating taxonomic units based on gross cultural morphology or ITS BLAST matches, the utility of phylogenetic tools for extracting robust phylogenies from environmental samples, the complementarity of culturing and environmental PCR, the utility of PD relative to traditional ecological indices, and the remarkably high diversity of foliar fungal endophytes in this simplified temperate ecosystem.
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Affiliation(s)
- A Elizabeth Arnold
- Department of Biology, Duke University, Durham, North Carolina 27708, USA.
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Henk DA, Vilgalys R. Molecular phylogeny suggests a single origin of insect symbiosis in the Pucciniomycetes with support for some relationships within the genus Septobasidium. Am J Bot 2007; 94:1515-1526. [PMID: 21636518 DOI: 10.3732/ajb.94.9.1515] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In the Pucciniomycetes, a class of fungi that includes the plant pathogenic rust fungi, insect parasitism is restricted to a single family, the Septobasidiaceae. The Septobasidiaceae form a variety of symbioses with scale insects and have remained largely unstudied since the 1930s. Transitions between plant and animal parasitism and between mutualism and parasitism cannot be fully addressed in the Basidiomycota without a clear phylogenetic hypothesis for the Septobasidiales. Here, molecular phylogenetic methods were applied to understand the origin of scale insect parasitism, test the monophyly of the order Septobasidiales, and evaluate the infrageneric concepts in the largest genus of scale insect parasites, Septobasidium. DNA sequence data from rRNA genes were used to infer higher-level relationships within the Pucciniomycetes, and data from translation elongation factor 1-alpha (tef1) were added for phylogenetic inference within the Septobasidiaceae. Data from tef1 revealed different intron arrangements within Septobasidium, but the molecule did not provide much additional phylogenetically informative data. Likelihood-model-based phylogenetic analyses of 44 Pucciniomycotina taxa provided moderate support for a single origin of insect parasitism. Within the Septobasidiaceae, there was little or no support for a monophyletic Septobasidium, and well-resolved subclades of Septobasidium species contradict previous morphological delimitations of groups within the genus.
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Affiliation(s)
- Daniel A Henk
- 10300 Baltimore Avenue, Room 304, Building 011A, Beltsville, Maryland 20705 USA
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Aime MC, Matheny PB, Henk DA, Frieders EM, Nilsson RH, Piepenbring M, McLaughlin DJ, Szabo LJ, Begerow D, Sampaio JP, Bauer R, Weiss M, Oberwinkler F, Hibbett D. An overview of the higher level classification of Pucciniomycotina based on combined analyses of nuclear large and small subunit rDNA sequences. Mycologia 2007; 98:896-905. [PMID: 17486966 DOI: 10.3852/mycologia.98.6.896] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In this study we provide a phylogenetically based introduction to the classes and orders of Pucciniomycotina (= Urediniomycetes), one of three subphyla of Basidiomycota. More than 8000 species of Pucciniomycotina have been described including putative saprotrophs and parasites of plants, animals and fungi. The overwhelming majority of these (approximately 90%) belong to a single order of obligate plant pathogens, the Pucciniales (= Uredinales), or rust fungi. We have assembled a dataset of previously published and newly generated sequence data from two nuclear rDNA genes (large subunit and small subunit) including exemplars from all known major groups in order to test hypotheses about evolutionary relationships among the Pucciniomycotina. The utility of combining nuc-lsu sequences spanning the entire D1-D3 region with complete nuc-ssu sequences for resolution and support of nodes is discussed. Our study confirms Pucciniomycotina as a monophyletic group of Basidiomycota. In total our results support eight major clades ranked as classes (Agaricostilbomycetes, Atractiellomycetes, Classiculomycetes, Cryptomycocolacomycetes, Cystobasidiomycetes, Microbotryomycetes, Mixiomycetes and Pucciniomycetes) and 18 orders.
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Affiliation(s)
- M Catherine Aime
- USDA-ARS, Systematic Botany and Mycology Lab, Beltsville, Maryland 20705, USA.
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Abstract
New species are described in Septobasidium, a genus of urediniomycete parasites on scale insects. One new species, S. gomezii, is described from Costa Rica, and another, S. meredithiae, is described from Louisiana. S. gomezii is most similar to S. septobasidioides, but macroscopic and microscopic differences support it being a distinct species. S. meredithiae is similar to S. alni and S. castaneum but differs from these species in several macroscopic and microscopic characters, especially when the species are observed on the same host tree and insect species. Another species collected only once in Costa Rica is listed with observations but it is not formally described here. This Septobasidium species shares some key characteristics with S. ramorum but combines a dense, compact, nearly black thallus and pigmented probasidia-like structures with spindle-shaped haustoria. Implications for taxonomy, morphological evolution and host specificity in Septobasidium are discussed.
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Affiliation(s)
- Daniel A Henk
- Department of Biology, Duke University, CB 90338, Durham, North Carolina 27708, USA.
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Henk DA, Weir A, Blackwell M. Laboulbeniopsis termitarius, an Ectoparasite of Termites Newly Recognized as a Member of the Laboulbeniomycetes. Mycologia 2003. [DOI: 10.2307/3761931] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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