1
|
Fox QN, Farah KN, Shaw OS, Pollowitz M, Sánchez-Conde A, Goodson C, Penczykowski RM. Effects of microclimate on disease prevalence across an urbanization gradient. Ecology 2024; 105:e4313. [PMID: 38708902 DOI: 10.1002/ecy.4313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 01/21/2024] [Accepted: 03/14/2024] [Indexed: 05/07/2024]
Abstract
Increased temperatures associated with urbanization (the "urban heat island" effect) have been shown to impact a wide range of traits across diverse taxa. At the same time, climatic conditions vary at fine spatial scales within habitats due to factors including shade from shrubs, trees, and built structures. Patches of shade may function as microclimate refugia that allow species to occur in habitats where high temperatures and/or exposure to ultraviolet radiation would otherwise be prohibitive. However, the importance of shaded microhabitats for interactions between species across urbanized landscapes remains poorly understood. Weedy plants and their foliar pathogens are a tractable system for studying how multiple scales of climatic variation influence infection prevalence. Powdery mildew pathogens are particularly well suited to this work, as these fungi can be visibly diagnosed on leaf surfaces. We studied the effects of shaded microclimates on rates of powdery mildew infection on Plantago host species in (1) "pandemic pivot" surveys in which undergraduate students recorded shade and infection status of thousands of plants along road verges in urban and suburban residential neighborhoods, (2) monthly surveys of plant populations in 22 parks along an urbanization gradient, and (3) a manipulative field experiment directly testing the effects of shade on the growth and transmission of powdery mildew. Together, our field survey results show strong positive effects of shade on mildew infection in wild Plantago populations across urban, suburban, and rural habitats. Our experiment suggests that this relationship is causal, where microclimate conditions associated with shade promote pathogen growth. Overall, infection prevalence increased with urbanization despite a negative association between urbanization and tree cover at the landscape scale. These findings highlight the importance of taking microclimate heterogeneity into account when establishing links between macroclimate or land use context and prevalence of disease.
Collapse
Affiliation(s)
- Quinn N Fox
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Keiko N Farah
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Olivia S Shaw
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Michelle Pollowitz
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | | | - Carrie Goodson
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | | |
Collapse
|
2
|
Salojärvi J, Rambani A, Yu Z, Guyot R, Strickler S, Lepelley M, Wang C, Rajaraman S, Rastas P, Zheng C, Muñoz DS, Meidanis J, Paschoal AR, Bawin Y, Krabbenhoft TJ, Wang ZQ, Fleck SJ, Aussel R, Bellanger L, Charpagne A, Fournier C, Kassam M, Lefebvre G, Métairon S, Moine D, Rigoreau M, Stolte J, Hamon P, Couturon E, Tranchant-Dubreuil C, Mukherjee M, Lan T, Engelhardt J, Stadler P, Correia De Lemos SM, Suzuki SI, Sumirat U, Wai CM, Dauchot N, Orozco-Arias S, Garavito A, Kiwuka C, Musoli P, Nalukenge A, Guichoux E, Reinout H, Smit M, Carretero-Paulet L, Filho OG, Braghini MT, Padilha L, Sera GH, Ruttink T, Henry R, Marraccini P, Van de Peer Y, Andrade A, Domingues D, Giuliano G, Mueller L, Pereira LF, Plaisance S, Poncet V, Rombauts S, Sankoff D, Albert VA, Crouzillat D, de Kochko A, Descombes P. The genome and population genomics of allopolyploid Coffea arabica reveal the diversification history of modern coffee cultivars. Nat Genet 2024; 56:721-731. [PMID: 38622339 PMCID: PMC11018527 DOI: 10.1038/s41588-024-01695-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 02/23/2024] [Indexed: 04/17/2024]
Abstract
Coffea arabica, an allotetraploid hybrid of Coffea eugenioides and Coffea canephora, is the source of approximately 60% of coffee products worldwide, and its cultivated accessions have undergone several population bottlenecks. We present chromosome-level assemblies of a di-haploid C. arabica accession and modern representatives of its diploid progenitors, C. eugenioides and C. canephora. The three species exhibit largely conserved genome structures between diploid parents and descendant subgenomes, with no obvious global subgenome dominance. We find evidence for a founding polyploidy event 350,000-610,000 years ago, followed by several pre-domestication bottlenecks, resulting in narrow genetic variation. A split between wild accessions and cultivar progenitors occurred ~30.5 thousand years ago, followed by a period of migration between the two populations. Analysis of modern varieties, including lines historically introgressed with C. canephora, highlights their breeding histories and loci that may contribute to pathogen resistance, laying the groundwork for future genomics-based breeding of C. arabica.
Collapse
Affiliation(s)
- Jarkko Salojärvi
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, Helsinki, Finland.
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore.
| | - Aditi Rambani
- Boyce Thompson Institute, Cornell University, Ithaca, NY, USA
| | - Zhe Yu
- Department of Mathematics and Statistics, University of Ottawa, Ottawa, Ontario, Canada
| | - Romain Guyot
- Institut de Recherche pour le Développement (IRD), Université de Montpellier, Montpellier, France
- Department of Electronics and Automation, Universidad Autónoma de Manizales, Manizales, Colombia
| | - Susan Strickler
- Boyce Thompson Institute, Cornell University, Ithaca, NY, USA
| | - Maud Lepelley
- Société des Produits Nestlé SA, Nestlé Research, Tours, France
| | - Cui Wang
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, Helsinki, Finland
| | - Sitaram Rajaraman
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, Helsinki, Finland
| | - Pasi Rastas
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Chunfang Zheng
- Department of Mathematics and Statistics, University of Ottawa, Ottawa, Ontario, Canada
| | - Daniella Santos Muñoz
- Department of Mathematics and Statistics, University of Ottawa, Ottawa, Ontario, Canada
| | - João Meidanis
- Institute of Computing, University of Campinas, Campinas, Brazil
| | - Alexandre Rossi Paschoal
- Department of Computer Science, The Federal University of Technology - Paraná (UTFPR), Cornélio Procópio, Brazil
| | - Yves Bawin
- Plant Sciences Unit, Flanders Research Institute for Agriculture, Fisheries and Food (ILVO), Melle, Belgium
| | | | - Zhen Qin Wang
- Department of Biological Sciences, University at Buffalo, Buffalo, NY, USA
| | - Steven J Fleck
- Department of Biological Sciences, University at Buffalo, Buffalo, NY, USA
| | - Rudy Aussel
- Société des Produits Nestlé SA, Nestlé Research, Tours, France
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Marseille, France
| | | | - Aline Charpagne
- Société des Produits Nestlé SA, Nestlé Research, Lausanne, Switzerland
| | - Coralie Fournier
- Société des Produits Nestlé SA, Nestlé Research, Lausanne, Switzerland
| | - Mohamed Kassam
- Société des Produits Nestlé SA, Nestlé Research, Lausanne, Switzerland
| | - Gregory Lefebvre
- Société des Produits Nestlé SA, Nestlé Research, Lausanne, Switzerland
| | - Sylviane Métairon
- Société des Produits Nestlé SA, Nestlé Research, Lausanne, Switzerland
| | - Déborah Moine
- Société des Produits Nestlé SA, Nestlé Research, Lausanne, Switzerland
| | - Michel Rigoreau
- Société des Produits Nestlé SA, Nestlé Research, Tours, France
| | - Jens Stolte
- Société des Produits Nestlé SA, Nestlé Research, Lausanne, Switzerland
| | - Perla Hamon
- Institut de Recherche pour le Développement (IRD), Université de Montpellier, Montpellier, France
| | - Emmanuel Couturon
- Institut de Recherche pour le Développement (IRD), Université de Montpellier, Montpellier, France
| | | | - Minakshi Mukherjee
- Department of Biological Sciences, University at Buffalo, Buffalo, NY, USA
| | - Tianying Lan
- Department of Biological Sciences, University at Buffalo, Buffalo, NY, USA
| | - Jan Engelhardt
- Department of Computer Science, University of Leipzig, Leipzig, Germany
| | - Peter Stadler
- Department of Computer Science, University of Leipzig, Leipzig, Germany
- Interdisciplinary Center for Bioinformatics, University of Leipzig, Leipzig, Germany
| | | | | | - Ucu Sumirat
- Indonesian Coffee and Cocoa Research Institute (ICCRI), Jember, Indonesia
| | - Ching Man Wai
- University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Nicolas Dauchot
- Research Unit in Plant Cellular and Molecular Biology, University of Namur, Namur, Belgium
| | - Simon Orozco-Arias
- Department of Electronics and Automation, Universidad Autónoma de Manizales, Manizales, Colombia
| | - Andrea Garavito
- Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad de Caldas, Manizales, Colombia
| | - Catherine Kiwuka
- National Agricultural Research Organization (NARO), Entebbe, Uganda
| | - Pascal Musoli
- National Agricultural Research Organization (NARO), Entebbe, Uganda
| | - Anne Nalukenge
- National Agricultural Research Organization (NARO), Entebbe, Uganda
| | - Erwan Guichoux
- Biodiversité Gènes & Communautés, INRA, Bordeaux, France
| | | | - Martin Smit
- Hortus Botanicus Amsterdam, Amsterdam, the Netherlands
| | | | - Oliveiro Guerreiro Filho
- Instituto Agronômico (IAC) Centro de Café 'Alcides Carvalho', Fazenda Santa Elisa, Campinas, Brazil
| | - Masako Toma Braghini
- Instituto Agronômico (IAC) Centro de Café 'Alcides Carvalho', Fazenda Santa Elisa, Campinas, Brazil
| | - Lilian Padilha
- Embrapa Café/Instituto Agronômico (IAC) Centro de Café 'Alcides Carvalho', Fazenda Santa Elisa, Campinas, Brazil
| | | | - Tom Ruttink
- Plant Sciences Unit, Flanders Research Institute for Agriculture, Fisheries and Food (ILVO), Melle, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
| | - Robert Henry
- Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Brisbane, Queensland, Australia
| | - Pierre Marraccini
- CIRAD - UMR DIADE (IRD-CIRAD-Université de Montpellier) BP 64501, Montpellier, France
| | - Yves Van de Peer
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- College of Horticulture, Academy for Advanced Interdisciplinary Studies, Nanjing Agricultural University, Nanjing, China
- Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Alan Andrade
- Embrapa Café/Inovacafé Laboratory of Molecular Genetics Campus da UFLA-MG, Lavras, Brazil
| | - Douglas Domingues
- Group of Genomics and Transcriptomes in Plants, São Paulo State University, UNESP, Rio Claro, Brazil
| | - Giovanni Giuliano
- Italian National Agency for New Technologies, Energy and Sustainable Economic Development, ENEA Casaccia Research Center, Rome, Italy
| | - Lukas Mueller
- Boyce Thompson Institute, Cornell University, Ithaca, NY, USA
| | - Luiz Filipe Pereira
- Embrapa Café/Lab. Biotecnologia, Área de Melhoramento Genético, Londrina, Brazil
| | | | - Valerie Poncet
- Institut de Recherche pour le Développement (IRD), Université de Montpellier, Montpellier, France
| | - Stephane Rombauts
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - David Sankoff
- Department of Mathematics and Statistics, University of Ottawa, Ottawa, Ontario, Canada
| | - Victor A Albert
- Department of Biological Sciences, University at Buffalo, Buffalo, NY, USA.
| | | | - Alexandre de Kochko
- Institut de Recherche pour le Développement (IRD), Université de Montpellier, Montpellier, France.
| | - Patrick Descombes
- Société des Produits Nestlé SA, Nestlé Research, Lausanne, Switzerland.
| |
Collapse
|
3
|
Penczykowski RM, Fearon ML, Hite JL, Shocket MS, Hall SR, Duffy MA. Pathways linking nutrient enrichment, habitat structure, and parasitism to host-resource interactions. Oecologia 2024; 204:439-449. [PMID: 37951848 DOI: 10.1007/s00442-023-05469-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 10/13/2023] [Indexed: 11/14/2023]
Abstract
Human activities simultaneously alter nutrient levels, habitat structure, and levels of parasitism. These activities likely have individual and joint impacts on food webs. Furthermore, there is particular concern that nutrient additions and changes to habitat structure might exacerbate the size of epidemics and impacts on host density. We used a well-studied zooplankton-fungus host-parasite system and experimental whole water column enclosures to factorially manipulate nutrient levels, habitat structure (specifically: mixing), and presence of parasites. Nutrient addition increased infection prevalence, density of infected hosts, and total host density. We hypothesized that nutrients, mixing, and parasitism were linked in multiple ways, including via their combined effects on phytoplankton (resource) abundance, and we used structural equation modeling to disentangle these pathways. In the absence of the parasite, both nutrients and mixing increased abundance of phytoplankton, whereas host density was negatively related to phytoplankton abundance, suggesting a mixture of bottom-up and top-down control of phytoplankton. In the presence of the parasite, nutrients still increased phytoplankton abundance but mixing no longer did, and there was no longer a significant relationship between host density and phytoplankton. This decoupling of host-resource dynamics may have resulted from reduced grazing due to illness-mediated changes in feeding behavior. Overall, our results show that the impact of one human activity (e.g., altered habitat structure) might depend on other human impacts (e.g., parasite introduction). Fortunately, carefully designed experiments and analyses can help tease apart these multifaceted relationships, allowing us to understand how human activities alter food webs, including interactions between hosts and their parasites and resources.
Collapse
Affiliation(s)
- Rachel M Penczykowski
- School of Biology, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
- Department of Biology, Washington University in St. Louis, St. Louis, MO, 63130, USA.
| | - Michelle L Fearon
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Jessica L Hite
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Marta S Shocket
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA
- Department of Geography, University of Florida, Gainesville, FL, 32611, USA
| | - Spencer R Hall
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA
| | - Meghan A Duffy
- School of Biology, Georgia Institute of Technology, Atlanta, GA, 30332, USA
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| |
Collapse
|
4
|
Boixel AL, Goyeau H, Berder J, Moinard J, Suffert F, Soubeyrand S, Sache I, Vidal T. A landscape-scale field survey demonstrates the role of wheat volunteers as a local and diversified source of leaf rust inoculum. Sci Rep 2023; 13:20411. [PMID: 37990120 PMCID: PMC10663564 DOI: 10.1038/s41598-023-47499-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 11/14/2023] [Indexed: 11/23/2023] Open
Abstract
Deploying disease-resistant cultivars is one of the most effective control strategies to manage crop diseases such as wheat leaf rust, caused by Puccinia triticina. After harvest, this biotrophic fungal pathogen can survive on wheat volunteers present at landscape scale and constitute a local source of primary inoculum for the next cropping season. In this study, we characterised the diversity of P. triticina populations surveyed on wheat volunteer seedlings for six consecutive years (2007-2012) at the landscape scale. A total of 642 leaf rust samples classified in 52 virulence profiles (pathotypes) were collected within a fixed 5-km radius. The pathotype composition (identity and abundance) of field-collected populations was analyzed according to the distance between the surveyed wheat plots and to the cultivars of origin of isolates. Our study emphasised the high diversity of P. triticina populations on wheat volunteers at the landscape scale. We observed an impact of cultivar of origin on pathogen population composition. Levels of population diversity differed between cultivars and their deployment in the study area. Our results suggest that wheat volunteers could provide a significant though highly variable contribution to the composition of primary inoculum and subsequent initiation of leaf rust epidemics.
Collapse
Affiliation(s)
- A-L Boixel
- Université Paris-Saclay, INRAE, UR BIOGER, 91123, Palaiseau, France
| | - H Goyeau
- Université Paris-Saclay, INRAE, UR BIOGER, 91123, Palaiseau, France
| | - J Berder
- Université Paris-Saclay, INRAE, UR BIOGER, 91123, Palaiseau, France
| | - J Moinard
- DRAAF Midi-Pyrénées, 31074, Toulouse, France
| | - F Suffert
- Université Paris-Saclay, INRAE, UR BIOGER, 91123, Palaiseau, France
| | | | - I Sache
- AgroParisTech, 91123, Palaiseau, France
| | - T Vidal
- Université Paris-Saclay, INRAE, UR BIOGER, 91123, Palaiseau, France.
| |
Collapse
|
5
|
Abstract
Plant diseases are strongly influenced by host biodiversity, spatial structure, and abiotic conditions. All of these are undergoing rapid change, as the climate is warming, habitats are being lost, and nitrogen deposition is changing nutrient dynamics of ecosystems with ensuing consequences for biodiversity. Here, I review examples of plant-pathogen associations to demonstrate how our ability to understand, model and predict disease dynamics is becoming increasingly difficult, as both plant and pathogen populations and communities are undergoing extensive change. The extent of this change is influenced via both direct and combined effects of global change drivers, and especially the latter are still poorly understood. Change at one trophic level is expected to drive change also at the other, and hence feedback loops between plants and their pathogens are expected to drive changes in disease risk both through ecological as well as evolutionary mechanisms. Many of the examples discussed here demonstrate an increase in disease risk as a result of ongoing change, suggesting that unless we successfully mitigate global environmental change, plant disease is going to become an increasingly heavy burden on our societies with far-reaching consequences for food security and functioning of ecosystems.
Collapse
Affiliation(s)
- Anna-Liisa Laine
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, 8057 Zürich, Switzerland; Research Centre for Ecological Change, Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, PO BOX 65 00014, University of Helsinki, Helsinki, Finland.
| |
Collapse
|
6
|
Norberg A, Susi H, Sallinen S, Baran P, Clark NJ, Laine AL. Direct and indirect viral associations predict coexistence in wild plant virus communities. Curr Biol 2023; 33:1665-1676.e4. [PMID: 37019108 DOI: 10.1016/j.cub.2023.03.022] [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: 11/02/2022] [Revised: 01/17/2023] [Accepted: 03/08/2023] [Indexed: 04/07/2023]
Abstract
Viruses are a vastly underestimated component of biodiversity that occur as diverse communities across hierarchical scales from the landscape level to individual hosts. The integration of community ecology with disease biology is a powerful, novel approach that can yield unprecedented insights into the abiotic and biotic drivers of pathogen community assembly. Here, we sampled wild plant populations to characterize and analyze the diversity and co-occurrence structure of within-host virus communities and their predictors. Our results show that these virus communities are characterized by diverse, non-random coinfections. Using a novel graphical network modeling framework, we demonstrate how environmental heterogeneity influences the network of virus taxa and how the virus co-occurrence patterns can be attributed to non-random, direct statistical virus-virus associations. Moreover, we show that environmental heterogeneity changed virus association networks, especially through their indirect effects. Our results highlight a previously underestimated mechanism of how environmental variability can influence disease risks by changing associations between viruses that are conditional on their environment.
Collapse
Affiliation(s)
- Anna Norberg
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, 8057 Zürich, Switzerland; Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, 7034 Trondheim, Norway.
| | - Hanna Susi
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, PO Box 65 00014, Helsinki, Finland
| | - Suvi Sallinen
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, PO Box 65 00014, Helsinki, Finland
| | - Pezhman Baran
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, PO Box 65 00014, Helsinki, Finland
| | - Nicholas J Clark
- School of Veterinary Science, Faculty of Science, University of Queensland, Gatton, QL 4343, Australia
| | - Anna-Liisa Laine
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, 8057 Zürich, Switzerland; Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, PO Box 65 00014, Helsinki, Finland
| |
Collapse
|
7
|
Jiranek J, Miller IF, An R, Bruns E, Metcalf CJE. Mechanistic models to meet the challenge of climate change in plant-pathogen systems. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220017. [PMID: 36744564 PMCID: PMC9900714 DOI: 10.1098/rstb.2022.0017] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Evidence that climate change will impact the ecology and evolution of individual plant species is growing. However, little, as yet, is known about how climate change will affect interactions between plants and their pathogens. Climate drivers could affect the physiology, and thus demography, and ultimately evolutionary processes affecting both plant hosts and their pathogens. Because the impacts of climate drivers may operate in different directions at different scales of infection, and, furthermore, may be nonlinear, abstracting across these processes may mis-specify outcomes. Here, we use mechanistic models of plant-pathogen interactions to illustrate how counterintuitive outcomes are possible, and we introduce how such framing may contribute to understanding climate effects on plant-pathogen systems. We discuss the evidence-base derived from wild and agricultural plant-pathogen systems that could inform such models, specifically in the direction of estimates of physiological, demographic and evolutionary responses to climate change. We conclude by providing an overview of knowledge gaps and directions for future research in this important area. This article is part of the theme issue 'Infectious disease ecology and evolution in a changing world'.
Collapse
Affiliation(s)
- Juliana Jiranek
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA.,Rocky Mountain Biological Laboratory, Crested Butte, CO 81244, USA
| | - Ian F Miller
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08450, USA.,Rocky Mountain Biological Laboratory, Crested Butte, CO 81244, USA
| | - Ruby An
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08450, USA
| | - Emme Bruns
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - C Jessica E Metcalf
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08450, USA
| |
Collapse
|
8
|
Eck JL, Kytöviita M, Laine A. Arbuscular mycorrhizal fungi influence host infection during epidemics in a wild plant pathosystem. THE NEW PHYTOLOGIST 2022; 236:1922-1935. [PMID: 36093733 PMCID: PMC9827988 DOI: 10.1111/nph.18481] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 08/15/2022] [Indexed: 05/29/2023]
Abstract
While pathogenic and mutualistic microbes are ubiquitous across ecosystems and often co-occur within hosts, how they interact to determine patterns of disease in genetically diverse wild populations is unknown. To test whether microbial mutualists provide protection against pathogens, and whether this varies among host genotypes, we conducted a field experiment in three naturally occurring epidemics of a fungal pathogen, Podosphaera plantaginis, infecting a host plant, Plantago lanceolata, in the Åland Islands, Finland. In each population, we collected epidemiological data on experimental plants from six allopatric populations that had been inoculated with a mixture of mutualistic arbuscular mycorrhizal fungi or a nonmycorrhizal control. Inoculation with arbuscular mycorrhizal fungi increased growth in plants from every population, but also increased host infection rate. Mycorrhizal effects on disease severity varied among host genotypes and strengthened over time during the epidemic. Host genotypes that were more susceptible to the pathogen received stronger protective effects from inoculation. Our results show that arbuscular mycorrhizal fungi introduce both benefits and risks to host plants, and shift patterns of infection in host populations under pathogen attack. Understanding how mutualists alter host susceptibility to disease will be important for predicting infection outcomes in ecological communities and in agriculture.
Collapse
Affiliation(s)
- Jenalle L. Eck
- Department of Evolutionary Biology and Environmental StudiesUniversity of Zurich8057ZurichSwitzerland
| | - Minna‐Maarit Kytöviita
- Department of Biological and Environmental ScienceUniversity of Jyväskylä40014JyväskyläFinland
| | - Anna‐Liisa Laine
- Department of Evolutionary Biology and Environmental StudiesUniversity of Zurich8057ZurichSwitzerland
- Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental SciencesUniversity of Helsinki00790HelsinkiFinland
| |
Collapse
|
9
|
Parasitism in heterogeneous landscapes: association between conserved habitats and gastrointestinal parasites in populations of wild mammals. Acta Trop 2022; 237:106751. [DOI: 10.1016/j.actatropica.2022.106751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 11/07/2022] [Accepted: 11/09/2022] [Indexed: 11/13/2022]
|
10
|
Spatially structured eco-evolutionary dynamics in a host-pathogen interaction render isolated populations vulnerable to disease. Nat Commun 2022; 13:6018. [PMID: 36229442 PMCID: PMC9561709 DOI: 10.1038/s41467-022-33665-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 09/27/2022] [Indexed: 11/08/2022] Open
Abstract
While the negative effects that pathogens have on their hosts are well-documented in humans and agricultural systems, direct evidence of pathogen-driven impacts in wild host populations is scarce and mixed. Here, to determine how the strength of pathogen-imposed selection depends on spatial structure, we analyze growth rates across approximately 4000 host populations of a perennial plant through time coupled with data on pathogen presence-absence. We find that infection decreases growth more in the isolated than well-connected host populations. Our inoculation study reveals isolated populations to be highly susceptible to disease while connected host populations support the highest levels of resistance diversity, regardless of their disease history. A spatial eco-evolutionary model predicts that non-linearity in the costs to resistance may be critical in determining this pattern. Overall, evolutionary feedbacks define the ecological impacts of disease in spatially structured systems with host gene flow being more important than disease history in determining the outcome.
Collapse
|
11
|
Wells K, Flynn R. Managing host-parasite interactions in humans and wildlife in times of global change. Parasitol Res 2022; 121:3063-3071. [PMID: 36066742 PMCID: PMC9446624 DOI: 10.1007/s00436-022-07649-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 08/30/2022] [Indexed: 11/24/2022]
Abstract
Global change in the Anthropocene has modified the environment of almost any species on earth, be it through climate change, habitat modifications, pollution, human intervention in the form of mass drug administration (MDA), or vaccination. This can have far-reaching consequences on all organisational levels of life, including eco-physiological stress at the cell and organism level, individual fitness and behaviour, population viability, species interactions and biodiversity. Host-parasite interactions often require highly adapted strategies by the parasite to survive and reproduce within the host environment and ensure efficient transmission among hosts. Yet, our understanding of the system-level outcomes of the intricate interplay of within host survival and among host parasite spread is in its infancy. We shed light on how global change affects host-parasite interactions at different organisational levels and address challenges and opportunities to work towards better-informed management of parasite control. We argue that global change affects host-parasite interactions in wildlife inhabiting natural environments rather differently than in humans and invasive species that benefit from anthropogenic environments as habitat and more deliberate rather than erratic exposure to therapeutic drugs and other control efforts.
Collapse
Affiliation(s)
- Konstans Wells
- Department of Biosciences, Swansea University, Swansea, SA28PP, UK.
| | - Robin Flynn
- Graduate Studies Office, South East Technological University, Cork Road Campus, Waterford, X91 K0EK, Ireland
| |
Collapse
|
12
|
Bubrig LT, Janisch AN, Tillet EM, Gibson AK. Contrasting parasite-mediated reductions in fitness within versus between patches of a nematode host. Evolution 2022; 76:1556-1564. [PMID: 35652582 PMCID: PMC9329228 DOI: 10.1111/evo.14521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 03/22/2022] [Accepted: 03/28/2022] [Indexed: 01/22/2023]
Abstract
Host and parasites interact across spatial scales, but parasite-mediated fitness effects are typically measured only at local scales. Recent work suggests that parasites can reduce host fitness during dispersal between patches, highlighting the potential for both within- and between-patch effects to contribute to the net fitness consequences of parasitism. Building on this work, we measured the contribution of the dispersal phase to parasite-mediated reductions in host fitness. We used the nematode Caenorhabditis elegans and its natural microsporidian parasite Nematocida parisii to quantify the fitness consequences of parasitism at the individual, population, and metapopulation level. Nematocida parisii reduced individual fecundity and population growth but had its greatest fitness impact at the dispersal stage: parasitism reduced the fitness of dispersing larvae by 62%-100%. These results indicate that the cost of parasitism in this system is greatly underestimated if the metapopulation level is not taken into account. We also found that the effects of N. parisii vary with host genotype, and the relative advantage of the most resistant genotype increases with inclusion of the dispersal stage. Taken together, our findings demonstrate that host-parasite interactions at the dispersal stage can magnify selection for parasite resistance.
Collapse
Affiliation(s)
- Louis T. Bubrig
- Department of BiologyUniversity of VirginiaCharlottesvilleVirginia22904
| | - Anne N. Janisch
- Department of BiologyUniversity of VirginiaCharlottesvilleVirginia22904
| | - Emily M. Tillet
- Department of BiologyUniversity of VirginiaCharlottesvilleVirginia22904
| | | |
Collapse
|
13
|
Sallinen S, Susi H, Halliday F, Laine AL. Altered within- and between-host transmission under coinfection underpin parasite co-occurrence patterns in the wild. Evol Ecol 2022; 37:131-151. [PMID: 36785621 PMCID: PMC9911512 DOI: 10.1007/s10682-022-10182-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 04/28/2022] [Indexed: 11/30/2022]
Abstract
Interactions among parasite species coinfecting the same host individual can have far reaching consequences for parasite ecology and evolution. How these within-host interactions affect epidemics may depend on two non-exclusive mechanisms: parasite growth and reproduction within hosts, and parasite transmission between hosts. Yet, how these two mechanisms operate under coinfection, and how sensitive they are to the composition of the coinfecting parasite community, remains poorly understood. Here, we test the hypothesis that the relationship between within- and between-host transmission of the fungal pathogen, Phomopsis subordinaria, is affected by co-occurring parasites infecting the host plant, Plantago lanceolata. We conducted a field experiment manipulating the parasite community of transmission source plants, then tracked P. subordinaria within-host transmission, as well as between-host transmission to naïve recipient plants. We find that coinfection with the powdery mildew pathogen, Podosphaera plantaginis, causes increased between-host transmission of P. subordinaria by affecting the number of infected flower stalks in the source plants, resulting from altered auto-infection. In contrast, coinfection with viruses did not have an effect on either within- or between-host transmission. We then analyzed data on the occurrence of P. subordinaria in 2018 and the powdery mildew in a multi-year survey data set from natural host populations to test whether the positive association predicted by our experimental results is evident in field epidemiological data. Consistent with our experimental findings, we observed a positive association in the occurrence of P. subordinaria and historical powdery mildew persistence. Jointly, our experimental and epidemiological results suggest that within- and between-host transmission of P. subordinaria depends on the identity of coinfecting parasites, with potentially far-reaching effects on disease dynamics and parasite co-occurrence patterns in wild populations. Supplementary Information The online version contains supplementary material available at 10.1007/s10682-022-10182-9.
Collapse
Affiliation(s)
- Suvi Sallinen
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, Viikinkaari 1 (PO box 65), 00014 Helsinki, Finland
| | - Hanna Susi
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, Viikinkaari 1 (PO box 65), 00014 Helsinki, Finland
| | - Fletcher Halliday
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, CH-8057 Zurich, Switzerland
| | - Anna-Liisa Laine
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, Viikinkaari 1 (PO box 65), 00014 Helsinki, Finland
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, CH-8057 Zurich, Switzerland
| |
Collapse
|
14
|
Bitters ME, Meyers J, Resasco J, Sarre SD, Tuff KT, Davies KF. Experimental habitat fragmentation disrupts host-parasite interaction over decades via life-cycle bottlenecks. Ecology 2022; 103:e3758. [PMID: 35581950 DOI: 10.1002/ecy.3758] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 02/08/2022] [Accepted: 02/23/2022] [Indexed: 11/06/2022]
Abstract
Habitat loss and fragmentation are likely to seriously impact parasites, a less studied but critical component of ecosystems, yet we lack long-term experimental evidence. Parasites structure communities, increase connectivity in food webs, and account for a large proportion of an ecosystem's total biomass. Food web models predict that parasites with multiple obligate hosts are at greater risk of extinction because the local extinction, or reduction in abundance, of any host will result in a life-cycle bottleneck for the parasite. We examine the response of a parasite and its multiple hosts to forest fragmentation over 26 years in the Wog Wog Habitat Fragmentation Experiment in southeastern Australia. The parasite is the nematode Hedruris wogwogensis, its intermediate host is the amphipod, Arcitalitrus sylvaticus, and its definitive host is the skink, Lampropholis guichenoti. In the first decade after fragmentation, nematodes completely disappeared from the matrix (plantation forestry) and all but disappeared from their definitive host (skinks) in fragments, and by the third decade after fragmentation had not appreciably recovered anywhere in the fragmented landscape compared to continuous forest. The low prevalence of the nematode in the fragmented landscape was associated with the low abundance of one or the other host in different decades: low abundance of the intermediate host (amphipod) in the first decade and low abundance of the definitive host (skink) in the third decade. In turn, the low abundance of each host was associated with changes to the abiotic environment over time due largely to the dynamically changing matrix as the plantation trees grew. Our study provides rare long-term experimental evidence of how disturbance can cause local extinction in parasites with life cycles dependent on more than one host species through population bottlenecks at any life stage. Mismatches in the abundance of multiple hosts over time are likely to be common following disturbance, thus causing parasites with complex life cycles to be particularly susceptible to habitat fragmentation and other disturbances. The integrity of food webs, communities, and ecosystems in fragmented landscapes may be more compromised than presently appreciated due to the sensitivity of parasites to habitat fragmentation.
Collapse
Affiliation(s)
- Matthew E Bitters
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO
| | - Jacqui Meyers
- CSIRO Land and Water, Black Mountain, Canberra, Australia Capital Territory, Australia
| | - Julian Resasco
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO
| | - Stephen D Sarre
- Institute for Applied Ecology, University of Canberra, Canberra, Australia Capital Territory, Australia
| | - Kika T Tuff
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO.,Impact Media Lab, Boulder, CO
| | - Kendi F Davies
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO
| |
Collapse
|
15
|
Mancy R, Rajeev M, Lugelo A, Brunker K, Cleaveland S, Ferguson EA, Hotopp K, Kazwala R, Magoto M, Rysava K, Haydon DT, Hampson K. Rabies shows how scale of transmission can enable acute infections to persist at low prevalence. Science 2022; 376:512-516. [PMID: 35482879 PMCID: PMC7613728 DOI: 10.1126/science.abn0713] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
How acute pathogens persist and what curtails their epidemic growth in the absence of acquired immunity remains unknown. Canine rabies is a fatal zoonosis that circulates endemically at low prevalence among domestic dogs in low- and middle-income countries. We traced rabies transmission in a population of 50,000 dogs in Tanzania from 2002 to 2016 and applied individual-based models to these spatially resolved data to investigate the mechanisms modulating transmission and the scale over which they operate. Although rabies prevalence never exceeded 0.15%, the best-fitting models demonstrated appreciable depletion of susceptible animals that occurred at local scales because of clusters of deaths and dogs already incubating infection. Individual variation in rabid dog behavior facilitated virus dispersal and cocirculation of virus lineages, enabling metapopulation persistence. These mechanisms have important implications for prediction and control of pathogens that circulate in spatially structured populations.
Collapse
Affiliation(s)
- Rebecca Mancy
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Malavika Rajeev
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Ahmed Lugelo
- Department of Veterinary Medicine and Public Health, Sokoine University of Agriculture, Morogoro, Tanzania
- Ifakara Health Institute, Dar es Salaam, Tanzania
| | - Kirstyn Brunker
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Sarah Cleaveland
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Elaine A. Ferguson
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Karen Hotopp
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Rudovick Kazwala
- Department of Veterinary Medicine and Public Health, Sokoine University of Agriculture, Morogoro, Tanzania
| | | | - Kristyna Rysava
- The Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, University of Warwick, Warwick, UK
| | - Daniel T. Haydon
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Katie Hampson
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| |
Collapse
|
16
|
Susi H, Sallinen S, Laine AL. Coinfection with a virus constrains within-host infection load but increases transmission potential of a highly virulent fungal plant pathogen. Ecol Evol 2022; 12:e8673. [PMID: 35342557 PMCID: PMC8928890 DOI: 10.1002/ece3.8673] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 02/07/2022] [Accepted: 02/07/2022] [Indexed: 12/23/2022] Open
Abstract
The trade‐off between within‐host infection rate and transmission to new hosts is predicted to constrain pathogen evolution, and to maintain polymorphism in pathogen populations. Pathogen life‐history stages and their correlations that underpin infection development may change under coinfection with other parasites as they compete for the same limited host resources. Cross‐kingdom interactions are common among pathogens in both natural and cultivated systems, yet their impacts on disease ecology and evolution are rarely studied. The host plant Plantago lanceolata is naturally infected by both Phomopsis subordinaria, a seed killing fungus, as well as Plantago lanceolata latent virus (PlLV) in the Åland Islands, SW Finland. We performed an inoculation assay to test whether coinfection with PlLV affects performance of two P. subordinaria strains, and the correlation between within‐host infection rate and transmission potential. The strains differed in the measured life‐history traits and their correlations. Moreover, we found that under virus coinfection, within‐host infection rate of P. subordinaria was smaller but transmission potential was higher compared to strains under single infection. The negative correlation between within‐host infection rate and transmission potential detected under single infection became positive under coinfection with PlLV. To understand whether within‐host and between‐host dynamics are correlated in wild populations, we surveyed 260 natural populations of P. lanceolata for P. subordinaria infection occurrence. When infections were found, we estimated between‐hosts dynamics by determining pathogen population size as the proportion of infected individuals, and within‐host dynamics by counting the proportion of infected flower stalks in 10 infected plants. In wild populations, the proportion of infected flower stalks was positively associated with pathogen population size. Jointly, our results suggest that the trade‐off between within‐host infection load and transmission may be strain specific, and that the pathogen life‐history that underpin epidemics may change depending on the diversity of infection, generating variation in disease dynamics.
Collapse
Affiliation(s)
- Hanna Susi
- Research Centre for Ecological Change, Organismal and Evolutionary Biology Research Programme University of Helsinki Helsinki Finland
| | - Suvi Sallinen
- Research Centre for Ecological Change, Organismal and Evolutionary Biology Research Programme University of Helsinki Helsinki Finland
| | - Anna-Liisa Laine
- Research Centre for Ecological Change, Organismal and Evolutionary Biology Research Programme University of Helsinki Helsinki Finland.,Department of Evolutionary Biology and Environmental Studies University of Zurich Zurich Switzerland
| |
Collapse
|
17
|
van Dijk LJA, Ehrlén J, Tack AJM. The relationship between pathogen life-history traits and metapopulation dynamics. THE NEW PHYTOLOGIST 2022; 233:2585-2598. [PMID: 34997974 PMCID: PMC9306763 DOI: 10.1111/nph.17948] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 12/17/2021] [Indexed: 06/14/2023]
Abstract
Plant pathogen traits, such as transmission mode and overwintering strategy, may have important effects on dispersal and persistence, and drive disease dynamics. Still, we lack insights into how life-history traits influence spatiotemporal disease dynamics. We adopted a multifaceted approach, combining experimental assays, theory and field surveys, to investigate whether information about two pathogen life-history traits - infectivity and overwintering strategy - can predict pathogen metapopulation dynamics in natural systems. For this, we focused on four fungal pathogens (two rust fungi, one chytrid fungus and one smut fungus) on the forest herb Anemone nemorosa. Pathogens infecting new plants mostly via spores (the chytrid and smut fungi) had higher patch occupancies and colonization rates than pathogens causing mainly systemic infections and overwintering in the rhizomes (the two rust fungi). Although the rust fungi more often occupied well-connected plant patches, the chytrid and smut fungi were equally or more common in isolated patches. Host patch size was positively related to patch occupancy and colonization rates for all pathogens. Predicting disease dynamics is crucial for understanding the ecological and evolutionary dynamics of host-pathogen interactions, and to prevent disease outbreaks. Our study shows that combining experiments, theory and field observations is a useful way to predict disease dynamics.
Collapse
Affiliation(s)
- Laura J. A. van Dijk
- Department of Ecology, Environment and Plant SciencesStockholm UniversitySE‐106 91StockholmSweden
| | - Johan Ehrlén
- Department of Ecology, Environment and Plant SciencesStockholm UniversitySE‐106 91StockholmSweden
| | - Ayco J. M. Tack
- Department of Ecology, Environment and Plant SciencesStockholm UniversitySE‐106 91StockholmSweden
| |
Collapse
|
18
|
Eck JL, Barrès B, Soubeyrand S, Sirén J, Numminen E, Laine AL. Strain Diversity and Spatial Distribution Are Linked to Epidemic Dynamics in Host Populations. Am Nat 2022; 199:59-74. [DOI: 10.1086/717179] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
19
|
Durrant R, Hamede R, Wells K, Lurgi M. Disruption of Metapopulation Structure Reduces Tasmanian Devil Facial Tumour Disease Spread at the Expense of Abundance and Genetic Diversity. Pathogens 2021; 10:pathogens10121592. [PMID: 34959547 PMCID: PMC8705368 DOI: 10.3390/pathogens10121592] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 11/26/2021] [Accepted: 12/06/2021] [Indexed: 11/16/2022] Open
Abstract
Metapopulation structure plays a fundamental role in the persistence of wildlife populations. It can also drive the spread of infectious diseases and transmissible cancers such as the Tasmanian devil facial tumour disease (DFTD). While disrupting this structure can reduce disease spread, it can also impair host resilience by disrupting gene flow and colonisation dynamics. Using an individual-based metapopulation model we investigated the synergistic effects of host dispersal, disease transmission rate and inter-individual contact distance for transmission, on the spread and persistence of DFTD from local to regional scales. Disease spread, and the ensuing population declines, are synergistically determined by individuals' dispersal, disease transmission rate and within-population mixing. Transmission rates can be magnified by high dispersal and inter-individual transmission distance. The isolation of local populations effectively reduced metapopulation-level disease prevalence but caused severe declines in metapopulation size and genetic diversity. The relative position of managed (i.e., isolated) local populations had a significant effect on disease prevalence, highlighting the importance of considering metapopulation structure when implementing metapopulation-scale disease control measures. Our findings suggest that population isolation is not an ideal management method for preventing disease spread in species inhabiting already fragmented landscapes, where genetic diversity and extinction risk are already a concern.
Collapse
Affiliation(s)
- Rowan Durrant
- Department of Biosciences, Swansea University, Singleton Park, Swansea SA2 8PP, UK; (R.D.); (K.W.)
| | - Rodrigo Hamede
- School of Natural Sciences, University of Tasmania, Hobart, TAS 7001, Australia;
| | - Konstans Wells
- Department of Biosciences, Swansea University, Singleton Park, Swansea SA2 8PP, UK; (R.D.); (K.W.)
| | - Miguel Lurgi
- Department of Biosciences, Swansea University, Singleton Park, Swansea SA2 8PP, UK; (R.D.); (K.W.)
- Correspondence: ; Tel.: +44-(0)-1792-602157
| |
Collapse
|
20
|
Karvonen A, Beck SV, Skúlason S, Kristjánsson BK, Leblanc CA. Variation in parasite resistance of Arctic charr, Salvelinus alpinus, between and within sympatric morphs. Ecol Evol 2021; 11:14024-14032. [PMID: 34707836 PMCID: PMC8525083 DOI: 10.1002/ece3.8109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 08/26/2021] [Accepted: 08/27/2021] [Indexed: 11/08/2022] Open
Abstract
Genetic variation in resistance against parasite infections is a predominant feature in host-parasite systems. However, mechanisms maintaining genetic polymorphism in resistance in natural host populations are generally poorly known. We explored whether differences in natural infection pressure between resource-based morphs of Arctic charr (Salvelinus alpinus) have resulted in differentiation in resistance profiles. We experimentally exposed offspring of two morphs from Lake Þingvallavatn (Iceland), the pelagic planktivorous charr ("murta") and the large benthivorous charr ("kuðungableikja"), to their common parasite, eye fluke Diplostomum baeri, infecting the eye humor. We found that there were no differences in resistance between the morphs, but clear differences among families within each morph. Moreover, we found suggestive evidence of resistance of offspring within families being positively correlated with the parasite load of the father, but not with that of the mother. Our results suggest that the inherited basis of parasite resistance in this system is likely to be related to variation among host individuals within each morph rather than ecological factors driving divergent resistance profiles at morph level. Overall, this may have implications for evolution of resistance through processes such as sexual selection.
Collapse
Affiliation(s)
- Anssi Karvonen
- Department of Biological and Environmental ScienceUniversity of JyvaskylaJyvaskylaFinland
| | - Samantha V. Beck
- Department of Aquaculture and Fish BiologyHólar UniversitySauðárkrókurIceland
- Galloway Fisheries TrustNewton StewartScotland
| | - Skúli Skúlason
- Department of Aquaculture and Fish BiologyHólar UniversitySauðárkrókurIceland
| | | | - Camille A. Leblanc
- Department of Aquaculture and Fish BiologyHólar UniversitySauðárkrókurIceland
| |
Collapse
|
21
|
McLeish M, Peláez A, Pagán I, Gavilán R, Fraile A, García-Arenal F. Structuring of plant communities across agricultural landscape mosaics: the importance of connectivity and the scale of effect. BMC Ecol Evol 2021; 21:173. [PMID: 34503449 PMCID: PMC8427894 DOI: 10.1186/s12862-021-01903-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 04/26/2021] [Indexed: 11/18/2022] Open
Abstract
Background Plant communities of fragmented agricultural landscapes, are subject to patch isolation and scale-dependent effects. Variation in configuration, composition, and distance from one another affect biological processes of disturbance, productivity, and the movement ecology of species. However, connectivity and spatial structuring among these diverse communities are rarely considered together in the investigation of biological processes. Spatially optimised predictor variables that are based on informed measures of connectivity among communities, offer a solution to untangling multiple processes that drive biodiversity. Results To address the gap between theory and practice, a novel spatial optimisation method that incorporates hypotheses of community connectivity, was used to estimate the scale of effect of biotic and abiotic factors that distinguish plant communities. We tested: (1) whether different hypotheses of connectivity among sites was important to measuring diversity and environmental variation among plant communities; and (2) whether spatially optimised variables of species relative abundance and the abiotic environment among communities were consistent with diversity parameters in distinguishing four habitat types; namely Crop, Edge, Oak, and Wasteland. The global estimates of spatial autocorrelation, which did not consider environmental variation among sites, indicated significant positive autocorrelation under four hypotheses of landscape connectivity. The spatially optimised approach indicated significant positive and negative autocorrelation of species relative abundance at fine and broad scales, which depended on the measure of connectivity and environmental variation among sites. Conclusions These findings showed that variation in community diversity parameters does not necessarily correspond to underlying spatial structuring of species relative abundance. The technique used to generate spatially-optimised predictors is extendible to incorporate multiple variables of interest along with a priori hypotheses of landscape connectivity. Spatially-optimised variables with appropriate definitions of connectivity might be better than diversity parameters in explaining functional differences among communities. Supplementary Information The online version contains supplementary material available at 10.1186/s12862-021-01903-9.
Collapse
Affiliation(s)
- Michael McLeish
- Centro de Biotecnología y Genómica de Plantas (CBGP, UPM-INIA), Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), and E.T.S.I. Agronómica, Alimentaria y de Biosistemas, Campus de Montegancedo, UPM, Pozuelo de Alarcón, 28223, Madrid, Spain.
| | - Adrián Peláez
- Centro de Biotecnología y Genómica de Plantas (CBGP, UPM-INIA), Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), and E.T.S.I. Agronómica, Alimentaria y de Biosistemas, Campus de Montegancedo, UPM, Pozuelo de Alarcón, 28223, Madrid, Spain
| | - Israel Pagán
- Centro de Biotecnología y Genómica de Plantas (CBGP, UPM-INIA), Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), and E.T.S.I. Agronómica, Alimentaria y de Biosistemas, Campus de Montegancedo, UPM, Pozuelo de Alarcón, 28223, Madrid, Spain
| | - Rosario Gavilán
- Unidad de Botánica, Departamento de Farmacología, Farmacognosia y Botánica, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Aurora Fraile
- Centro de Biotecnología y Genómica de Plantas (CBGP, UPM-INIA), Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), and E.T.S.I. Agronómica, Alimentaria y de Biosistemas, Campus de Montegancedo, UPM, Pozuelo de Alarcón, 28223, Madrid, Spain
| | - Fernando García-Arenal
- Centro de Biotecnología y Genómica de Plantas (CBGP, UPM-INIA), Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), and E.T.S.I. Agronómica, Alimentaria y de Biosistemas, Campus de Montegancedo, UPM, Pozuelo de Alarcón, 28223, Madrid, Spain
| |
Collapse
|
22
|
Faticov M, Abdelfattah A, Roslin T, Vacher C, Hambäck P, Blanchet FG, Lindahl BD, Tack AJM. Climate warming dominates over plant genotype in shaping the seasonal trajectory of foliar fungal communities on oak. THE NEW PHYTOLOGIST 2021; 231:1770-1783. [PMID: 33960441 DOI: 10.1111/nph.17434] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Accepted: 04/15/2021] [Indexed: 05/13/2023]
Abstract
Leaves interact with a wealth of microorganisms. Among these, fungi are highly diverse and are known to contribute to plant health, leaf senescence and early decomposition. However, patterns and drivers of the seasonal dynamics of foliar fungal communities are poorly understood. We used a multifactorial experiment to investigate the influence of warming and tree genotype on the foliar fungal community on the pedunculate oak Quercus robur across one growing season. Fungal species richness increased, evenness tended to decrease, and community composition strongly shifted during the growing season. Yeasts increased in relative abundance as the season progressed, while putative fungal pathogens decreased. Warming decreased species richness, reduced evenness and changed community composition, especially at the end of the growing season. Warming also negatively affected putative fungal pathogens. We only detected a minor imprint of tree genotype and warming × genotype interactions on species richness and community composition. Overall, our findings demonstrate that warming plays a larger role than plant genotype in shaping the seasonal dynamics of the foliar fungal community on oak. These warming-induced shifts in the foliar fungal community may have a pronounced impact on plant health, plant-fungal interactions and ecosystem functions.
Collapse
Affiliation(s)
- Maria Faticov
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Svante Arrhenius väg 20A, Stockholm, SE-106 91, Sweden
| | - Ahmed Abdelfattah
- Institute of Environmental Biotechnology, Graz University of Technology, Petersgasse 12, Graz, A-8010, Austria
| | - Tomas Roslin
- Department of Ecology, Swedish University of Agricultural Sciences, PO Box 7044, Uppsala, SE-756 51, Sweden
| | | | - Peter Hambäck
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Svante Arrhenius väg 20A, Stockholm, SE-106 91, Sweden
| | - F Guillaume Blanchet
- Département de Biologie, Faculté des Sciences, Université de Sherbrooke, 2500 Boulevard Université, Sherbrooke, QC, J1K 2R1, Canada
- Département de Mathématique, Faculté des Sciences, Université de Sherbrooke, 2500 Boulevard Université, Sherbrooke, QC, J1K 2R1, Canada
- Département des Sciences de la Santé Communautaire, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 3001 12e Avenue Nord, Sherbrooke, QC, J1H 5N4, Canada
| | - Björn D Lindahl
- Department of Soil and Environment, Swedish University of Agricultural Sciences, PO Box 7014, Uppsala, SE-750 07, Sweden
| | - Ayco J M Tack
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Svante Arrhenius väg 20A, Stockholm, SE-106 91, Sweden
| |
Collapse
|
23
|
Bourgeois Y, Fields P, Bento G, Ebert D. Balancing selection for pathogen resistance reveals an intercontinental signature of Red Queen coevolution. Mol Biol Evol 2021; 38:4918-4933. [PMID: 34289047 PMCID: PMC8557431 DOI: 10.1093/molbev/msab217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The link between long-term host–parasite coevolution and genetic diversity is key to understanding genetic epidemiology and the evolution of resistance. The model of Red Queen host–parasite coevolution posits that high genetic diversity is maintained when rare host resistance variants have a selective advantage, which is believed to be the mechanistic basis for the extraordinarily high levels of diversity at disease-related genes such as the major histocompatibility complex in jawed vertebrates and R-genes in plants. The parasites that drive long-term coevolution are, however, often elusive. Here we present evidence for long-term balancing selection at the phenotypic (variation in resistance) and genomic (resistance locus) level in a particular host–parasite system: the planktonic crustacean Daphnia magna and the bacterium Pasteuria ramosa. The host shows widespread polymorphisms for pathogen resistance regardless of geographic distance, even though there is a clear genome-wide pattern of isolation by distance at other sites. In the genomic region of a previously identified resistance supergene, we observed consistent molecular signals of balancing selection, including higher genetic diversity, older coalescence times, and lower differentiation between populations, which set this region apart from the rest of the genome. We propose that specific long-term coevolution by negative-frequency-dependent selection drives this elevated diversity at the host's resistance loci on an intercontinental scale and provide an example of a direct link between the host’s resistance to a virulent pathogen and the large-scale diversity of its underlying genes.
Collapse
Affiliation(s)
- Yann Bourgeois
- University of Basel, Department of Environmental Sciences, Zoology, Vesalgasse 1, 4051 Basel, Switzerland
| | - Peter Fields
- University of Basel, Department of Environmental Sciences, Zoology, Vesalgasse 1, 4051 Basel, Switzerland
| | - Gilberto Bento
- University of Basel, Department of Environmental Sciences, Zoology, Vesalgasse 1, 4051 Basel, Switzerland
| | - Dieter Ebert
- University of Basel, Department of Environmental Sciences, Zoology, Vesalgasse 1, 4051 Basel, Switzerland
| |
Collapse
|
24
|
Safdari P, Höckerstedt L, Brosche M, Salojärvi J, Laine AL. Genotype-Specific Expression and NLR Repertoire Contribute to Phenotypic Resistance Diversity in Plantago lanceolata. FRONTIERS IN PLANT SCIENCE 2021; 12:675760. [PMID: 34322142 PMCID: PMC8311189 DOI: 10.3389/fpls.2021.675760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 06/14/2021] [Indexed: 06/13/2023]
Abstract
High levels of phenotypic variation in resistance appears to be nearly ubiquitous across natural host populations. Molecular processes contributing to this variation in nature are still poorly known, although theory predicts resistance to evolve at specific loci driven by pathogen-imposed selection. Nucleotide-binding leucine-rich repeat (NLR) genes play an important role in pathogen recognition, downstream defense responses and defense signaling. Identifying the natural variation in NLRs has the potential to increase our understanding of how NLR diversity is generated and maintained, and how to manage disease resistance. Here, we sequenced the transcriptomes of five different Plantago lanceolata genotypes when inoculated by the same strain of obligate fungal pathogen Podosphaera plantaginis. A de novo transcriptome assembly of RNA-sequencing data yielded 24,332 gene models with N50 value of 1,329 base pairs and gene space completeness of 66.5%. The gene expression data showed highly varying responses where each plant genotype demonstrated a unique expression profile in response to the pathogen, regardless of the resistance phenotype. Analysis on the conserved NB-ARC domain demonstrated a diverse NLR repertoire in P. lanceolata consistent with the high phenotypic resistance diversity in this species. We find evidence of selection generating diversity at some of the NLR loci. Jointly, our results demonstrate that phenotypic resistance diversity results from a crosstalk between different defense mechanisms. In conclusion, characterizing the architecture of resistance in natural host populations may shed unprecedented light on the potential of evolution to generate variation.
Collapse
Affiliation(s)
- Pezhman Safdari
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, Helsinki, Finland
| | - Layla Höckerstedt
- Climate System Research, Finnish Meteorological Institute, Helsinki, Finland
| | - Mikael Brosche
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, Helsinki, Finland
| | - Jarkko Salojärvi
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, Helsinki, Finland
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Anna-Liisa Laine
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, Helsinki, Finland
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| |
Collapse
|
25
|
Bozzuto C, Canessa S, Koella JC. Exploring artificial habitat fragmentation to control invasion by infectious wildlife diseases. Theor Popul Biol 2021; 141:14-23. [PMID: 34139201 DOI: 10.1016/j.tpb.2021.06.001] [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: 01/21/2020] [Revised: 05/26/2021] [Accepted: 06/01/2021] [Indexed: 10/21/2022]
Abstract
One way to reduce the impacts of invading wildlife diseases is setting up fences that would reduce the spread of pathogens by limiting connectivity, similarly to exclusion fences that are commonly used to conserve threatened species against invasive predators. One of the problems with fences is that, while they may have the short-term benefit of impeding the spread of disease, this benefit may be offset by potential long-term ecological costs of fragmentation by fencing. However, managers facing situations where a pathogen has been detected near the habitat of a (highly) vulnerable species may be willing to explore such a trade-off. To aid such exploration quantitatively, we present a series of models trading off the benefits of fragmentation (potential reduction of disease impacts on susceptible individuals) against its costs (both financial and ecological, i.e. reduced viability in the patches created by fragmentation), and exploring the effects of fragmentation on non-target species richness. For all model variants we derive the optimal number of artificial patches. We show that pre-emptive disease fences may have benefits when the risk of disease exceeds the impacts of fragmentation, when fence failure rates are lower than a specific threshold, and when sufficient resources are available to implement optimal solutions. A useful step to initiate planning is to obtain information about the expected number of initial infection events and on the host's extinction threshold with respect to the focal habitat and management duration. Our approach can assist managers to identify whether the trade-offs support the decision to fence and how intensive fragmentation should be.
Collapse
Affiliation(s)
- Claudio Bozzuto
- Wildlife Analysis GmbH, Oetlisbergstrasse 38, 8053 Zurich, Switzerland.
| | - Stefano Canessa
- Wildlife Health Ghent, Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Jacob C Koella
- Laboratory of ecology and epidemiology of parasites, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| |
Collapse
|
26
|
Susi H, Laine A. Agricultural land use disrupts biodiversity mediation of virus infections in wild plant populations. THE NEW PHYTOLOGIST 2021; 230:2447-2458. [PMID: 33341977 PMCID: PMC8248426 DOI: 10.1111/nph.17156] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 12/10/2020] [Indexed: 06/08/2023]
Abstract
Human alteration of natural habitats may change the processes governing species interactions in wild communities. Wild populations are increasingly impacted by agricultural intensification, yet it is unknown whether this alters biodiversity mediation of disease dynamics. We investigated the association between plant diversity (species richness, diversity) and infection risk (virus richness, prevalence) in populations of Plantago lanceolata in natural landscapes as well as those occurring at the edges of cultivated fields. Altogether, 27 P. lanceolata populations were surveyed for population characteristics and sampled for PCR detection of five recently characterized viruses. We find that plant species richness and diversity correlated negatively with virus infection prevalence. Virus species richness declined with increasing plant diversity and richness in natural populations while in agricultural edge populations species richness was moderately higher, and not associated with plant richness. This difference was not explained by changes in host richness between these two habitats, suggesting potential pathogen spill-over and increased transmission of viruses across the agro-ecological interface. Host population connectivity significantly decreased virus infection prevalence. We conclude that human use of landscapes may change the ecological laws by which natural communities are formed with far reaching implications for ecosystem functioning and disease.
Collapse
Affiliation(s)
- Hanna Susi
- Research Centre for Ecological Change, Organismal and Evolutionary Biology Research ProgrammeUniversity of HelsinkiPO Box 65Helsinki00014Finland
| | - Anna‐Liisa Laine
- Research Centre for Ecological Change, Organismal and Evolutionary Biology Research ProgrammeUniversity of HelsinkiPO Box 65Helsinki00014Finland
- Department of Evolutionary Biology and Environmental StudiesUniversity of ZurichWinterthurerstrasse 190ZurichCH‐8057Switzerland
| |
Collapse
|
27
|
Penczykowski RM, Sieg RD. Plantago spp. as Models for Studying the Ecology and Evolution of Species Interactions across Environmental Gradients. Am Nat 2021; 198:158-176. [PMID: 34143715 DOI: 10.1086/714589] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractA central challenge in ecology and evolutionary biology is to understand how variation in abiotic and biotic factors combine to shape the distribution, abundance, and diversity of focal species. Environmental gradients, whether natural (e.g., latitude, elevation, ocean proximity) or anthropogenic (e.g., land-use intensity, urbanization), provide compelling settings for addressing this challenge. However, not all organisms are amenable to the observational and experimental approaches required for untangling the factors that structure species along gradients. Here we highlight herbaceous plants in the genus Plantago as models for studying the ecology and evolution of species interactions along abiotic gradients. Plantago lanceolata and P. major are native to Europe and Asia but distributed globally, and they are established models for studying population ecology and interactions with herbivores, pathogens, and soil microbes. Studying restricted range congeners in comparison with those cosmopolitan species can provide insight into abiotic and biotic determinants of range size and population structure. We highlight one such species, P. rugelii, which is endemic to eastern North America. We give an overview of the literature on these focal Plantago species and explain why they are logical candidates for studies of species interactions across environmental gradients. Finally, we emphasize collaborative and community science approaches that can facilitate such research and note the amenability of Plantago for authentic research projects in science education.
Collapse
|
28
|
Benítez-Malvido J, Rodríguez-Alvarado G, Álvarez-Añorve M, Ávila-Cabadilla LD, del-Val E, Lira-Noriega A, Gregorio-Cipriano R. Antagonistic Interactions Between Fusaria Species and Their Host Plants Are Influenced by Host Taxonomic Distance: A Case Study From Mexico. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.615857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Interactions between cultivated and wild plants with their fungal pathogens have strong ecological, evolutionary and economic implications. Antagonistic interactions, however, have been scantily studied in an applied context by using ecological networks, phylogeny and spatial ecology concurrently. In this study, we describe for the first time, the topological structure of plant-fungi networks involving species of the genus Fusarium and their native and introduced (exotic) cultivated host plants in Mexico. For this, we based our study on a recent database describing the attack on 75 native and introduced plant species, including 35 species of the genus Fusarium. Host plant species varied in their degree of phylogenetical relatedness (Monocots and Dicots) and spatial geographical distribution. Therefore, we also tested whether or not plant-Fusarium networks are phylogenetically structured and highlighted the spatial correlation between pathogens and their host plants across the country. In general, the pathogen-plant network is more specialized and compartmentalized in closely related taxa. Closely related hosts are more likely to share the same pathogenic Fusarium species. Host plants are present in different ecosystems and climates, with regions having more cultivated plant species presenting the highest number of fusaria pathogens. From an economic standpoint, different species of the same taxonomic family may be more susceptible to being attacked by the same species of Fusarium, whereas from an ecological standpoint the movement of pathogens may expose wild and cultivated plants to new diseases. Our study highlights the relevance of interaction intimacy in structuring trophic relationships between plants and fusaria species in native and introduced species. Furthermore, we show that the analytical tools regarding host distribution and phylogeny could permit a rapid assessment of which plant species in a region are most likely to be attacked by a given fusaria.
Collapse
|
29
|
Searle CL, Christie MR. Evolutionary rescue in host-pathogen systems. Evolution 2021; 75:2948-2958. [PMID: 34018610 DOI: 10.1111/evo.14269] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 05/07/2021] [Accepted: 05/12/2021] [Indexed: 11/28/2022]
Abstract
Natural populations encounter a variety of threats that can increase their risk of extinction. Populations can avoid extinction through evolutionary rescue (ER), which occurs when an adaptive, genetic response to selection allows a population to recover from an environmental change that would otherwise cause extinction. While the traditional framework for ER was developed with abiotic risk factors in mind, ER may also occur in response to a biotic source of demographic change, such as the introduction of a novel pathogen. We first describe how ER in response to a pathogen differs from the traditional ER framework; density-dependent transmission, pathogen evolution, and pathogen extinction can change the strength of selection imposed by a pathogen and make host population persistence more likely. We also discuss several variables that affect traditional ER (abundance, genetic diversity, population connectivity, and community composition) that also directly affect disease risk resulting in diverse outcomes for ER in host-pathogen systems. Thus, generalizations developed in studies of traditional ER may not be relevant for ER in response to the introduction of a pathogen. Incorporating pathogens into the framework of ER will lead to a better understanding of how and when populations can avoid extinction in response to novel pathogens.
Collapse
Affiliation(s)
- Catherine L Searle
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, 47907
| | - Mark R Christie
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, 47907.,Department of Forestry and Natural Resources, Purdue University, West Lafayette, Indiana, 47907
| |
Collapse
|
30
|
Höckerstedt L, Susi H, Laine A. Effect of maternal infection on progeny growth and resistance mediated by maternal genotype and nutrient availability. THE JOURNAL OF ECOLOGY 2021; 109:1439-1451. [PMID: 33776136 PMCID: PMC7986887 DOI: 10.1111/1365-2745.13568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 11/26/2020] [Indexed: 06/12/2023]
Abstract
Maternal effects of pathogen infection on progeny development and disease resistance may be adaptive and have important consequences for population dynamics. However, these effects are often context-dependent and examples of adaptive transgenerational responses from perennials are scarce, although they may be a particularly important mechanism generating variation in the offspring of long-lived species.Here, we studied the effect of maternal infection of Plantago lanceolata by Podosphaera plantaginis, a fungal parasite, on the growth, flower production and resistance of the progeny of six maternal genotypes in nutrient-rich and nutrient-poor environments. For this purpose, we combined a common garden study with automated phenotyping measurements of early life stages, and an inoculation experiment.Our results show that the effects of infection on the mother plants transcend to impact their progeny. Although maternal infection decreased total leaf and flower production of the progeny by the end of the growing season, it accelerated early growth and enhanced resistance to the pathogen P. plantaginis.We also discovered that the effects of maternal infection affected progeny development and resistance through a three way-interaction between maternal genotype, maternal infection status and nutrient availability. Synthesis. Our results emphasize the importance of maternal effects mediated through genotypic and environmental factors in long-living perennials and suggest that maternal infection can create a layer of phenotypic diversity in resistance. These results may have important implications for both epidemiological and evolutionary dynamics of host-parasite interactions in the wild.
Collapse
Affiliation(s)
- Layla Höckerstedt
- Research Centre for Ecological Change, Organismal and Evolutionary BiologyFaculty of Biological and Environmental SciencesUniversity of HelsinkiHelsinkiFinland
- Climate System ResearchFinnish Meteorological InstituteHelsinkiFinland
| | - Hanna Susi
- Research Centre for Ecological Change, Organismal and Evolutionary BiologyFaculty of Biological and Environmental SciencesUniversity of HelsinkiHelsinkiFinland
| | - Anna‐Liisa Laine
- Research Centre for Ecological Change, Organismal and Evolutionary BiologyFaculty of Biological and Environmental SciencesUniversity of HelsinkiHelsinkiFinland
- Department of Evolutionary Biology and Environmental StudiesUniversity of ZurichZurichSwitzerland
| |
Collapse
|
31
|
Nørgaard LS, Zilio G, Saade C, Gougat‐Barbera C, Hall MD, Fronhofer EA, Kaltz O. An evolutionary trade‐off between parasite virulence and dispersal at experimental invasion fronts. Ecol Lett 2021; 24:739-750. [DOI: 10.1111/ele.13692] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 11/30/2020] [Accepted: 12/23/2020] [Indexed: 11/29/2022]
Affiliation(s)
- Louise S. Nørgaard
- School of Biological Sciences Centre for Geometric Biology Monash University Melbourne3800Australia
- ISEMUniversity of MontpellierCNRSIRDEPHE Montpellier France
| | - Giacomo Zilio
- ISEMUniversity of MontpellierCNRSIRDEPHE Montpellier France
| | - Camille Saade
- ISEMUniversity of MontpellierCNRSIRDEPHE Montpellier France
| | | | - Matthew D. Hall
- School of Biological Sciences Centre for Geometric Biology Monash University Melbourne3800Australia
| | | | - Oliver Kaltz
- ISEMUniversity of MontpellierCNRSIRDEPHE Montpellier France
| |
Collapse
|
32
|
Papaïx J, Burdon JJ, Walker E, Barrett LG, Thrall PH. Metapopulation Structure Predicts Population Dynamics in the Cakile maritima- Alternaria brassicicola Host-Pathogen Interaction. Am Nat 2021; 197:E55-E71. [PMID: 33523787 DOI: 10.1086/712248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractIn symbiotic interactions, spatiotemporal variation in the distribution or population dynamics of one species represents spatial and temporal heterogeneity of the landscape for the other. Such interdependent demographic dynamics result in situations where the relative importance of biotic and abiotic factors in determining ecological processes is complicated to decipher. Using a detailed survey of three metapopulations of the succulent plant Cakile maritima and the necrotrophic fungus Alternaria brassicicola located along the southeastern Australian coast, we developed a series of statistical analyses-namely, synchrony analysis, patch occupancy dynamics, and a spatially explicit metapopulation model-to understand how habitat quality, weather conditions, dispersal, and spatial structure determine metapopulation dynamics. Climatic conditions are important drivers, likely explaining the high synchrony among populations. Host availability, landscape features facilitating dispersal, and habitat conditions also impact the occurrence and spread of disease. Overall, we show that the collection of extensive data on host and pathogen population dynamics, in combination with spatially explicit epidemiological modeling, makes it possible to accurately predict disease dynamics-even when there is extreme variability in host population dynamics. Finally, we discuss the importance of genetic information for predicting demographic dynamics in this pathosystem.
Collapse
|
33
|
Valenzuela-Sánchez A, Wilber MQ, Canessa S, Bacigalupe LD, Muths E, Schmidt BR, Cunningham AA, Ozgul A, Johnson PTJ, Cayuela H. Why disease ecology needs life-history theory: a host perspective. Ecol Lett 2021; 24:876-890. [PMID: 33492776 DOI: 10.1111/ele.13681] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 12/16/2020] [Accepted: 12/18/2020] [Indexed: 12/16/2022]
Abstract
When facing an emerging infectious disease of conservation concern, we often have little information on the nature of the host-parasite interaction to inform management decisions. However, it is becoming increasingly clear that the life-history strategies of host species can be predictive of individual- and population-level responses to infectious disease, even without detailed knowledge on the specifics of the host-parasite interaction. Here, we argue that a deeper integration of life-history theory into disease ecology is timely and necessary to improve our capacity to understand, predict and mitigate the impact of endemic and emerging infectious diseases in wild populations. Using wild vertebrates as an example, we show that host life-history characteristics influence host responses to parasitism at different levels of organisation, from individuals to communities. We also highlight knowledge gaps and future directions for the study of life-history and host responses to parasitism. We conclude by illustrating how this theoretical insight can inform the monitoring and control of infectious diseases in wildlife.
Collapse
Affiliation(s)
- Andrés Valenzuela-Sánchez
- Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Valdivia, Chile.,ONG Ranita de Darwin, Valdivia and Santiago, Chile.,Centro de Investigación para la Sustentabilidad, Universidad Andrés Bello, Santiago, Chile
| | - Mark Q Wilber
- Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA.,Center for Wildlife Health, Department of Forestry, Wildlife and Fisheries, University of Tennessee Institute of Agriculture, Knoxville, TN, 37996, USA
| | - Stefano Canessa
- Wildlife Health Ghent, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Leonardo D Bacigalupe
- Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Valdivia, Chile
| | - Erin Muths
- U.S. Geological Survey, 2150 Centre Avenue Bldg C, Fort Collins, Colorado, 80526, USA
| | - Benedikt R Schmidt
- Institut für Evolutionsbiologie und Umweltwissenschaften, Universität Zürich, Winterthurerstrasse 190, 8057, Zürich, Switzerland.,Info Fauna Karch, UniMail, Bâtiment G, Bellevaux 51, 2000, Neuchâtel, Switzerland
| | - Andrew A Cunningham
- Institute of Zoology, Zoological Society of London, Regent's Park, London, NW1 4RY, UK
| | - Arpat Ozgul
- Institut für Evolutionsbiologie und Umweltwissenschaften, Universität Zürich, Winterthurerstrasse 190, 8057, Zürich, Switzerland
| | - Pieter T J Johnson
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, 80309, USA
| | - Hugo Cayuela
- IBIS, Department of Biology, University Laval, Pavillon Charles-Eugène-Marchand, Avenue de la Médecine, Quebec City, Canada.,Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland
| |
Collapse
|
34
|
Sallinen S, Norberg A, Susi H, Laine AL. Intraspecific host variation plays a key role in virus community assembly. Nat Commun 2020; 11:5610. [PMID: 33154373 PMCID: PMC7644774 DOI: 10.1038/s41467-020-19273-z] [Citation(s) in RCA: 20] [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: 03/31/2020] [Accepted: 10/05/2020] [Indexed: 12/31/2022] Open
Abstract
Infection by multiple pathogens of the same host is ubiquitous in both natural and managed habitats. While intraspecific variation in disease resistance is known to affect pathogen occurrence, how differences among host genotypes affect the assembly of pathogen communities remains untested. In our experiment using cloned replicates of naive Plantago lanceolata plants as sentinels during a seasonal virus epidemic, we find non-random co-occurrence patterns of five focal viruses. Using joint species distribution modelling, we attribute the non-random virus occurrence patterns primarily to differences among host genotypes and local population context. Our results show that intraspecific variation among host genotypes may play a large, previously unquantified role in pathogen community structure.
Collapse
Affiliation(s)
- Suvi Sallinen
- Organismal and Evolutionary Biology Research Programme, Viikinkaari 1 (PO box 65), FI-00014, University of Helsinki, Helsinki, Finland.
| | - Anna Norberg
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, CH-8067, Zürich, Switzerland
| | - Hanna Susi
- Organismal and Evolutionary Biology Research Programme, Viikinkaari 1 (PO box 65), FI-00014, University of Helsinki, Helsinki, Finland
| | - Anna-Liisa Laine
- Organismal and Evolutionary Biology Research Programme, Viikinkaari 1 (PO box 65), FI-00014, University of Helsinki, Helsinki, Finland
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, CH-8067, Zürich, Switzerland
| |
Collapse
|
35
|
Bell SC, Heard GW, Berger L, Skerratt LF. Connectivity over a disease risk gradient enables recovery of rainforest frogs. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2020; 30:e02152. [PMID: 32343856 DOI: 10.1002/eap.2152] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 02/14/2020] [Accepted: 03/30/2020] [Indexed: 06/11/2023]
Abstract
Chytridiomycosis has been a key driver of global frog declines and extinctions, particularly for high-altitude populations across Australia and the Americas. While recent evidence shows some species are recovering, the extent of such recoveries and the mechanisms underpinning them remain poorly resolved. We surveyed the historical latitudinal and elevational range of four Australian rainforest frogs that disappeared from upland sites between 1989 and 1994 to establish their contemporary distribution and elevational limits, and investigate factors affecting population recovery. Five rainforest streams were surveyed from mountain-base to summit (30 sites in total), with swabs collected from the target species (Litoria dayi, L. nannotis, L. rheocola, and L. serrata) to determine their infection status, and data loggers deployed to measure microclimatic variation across the elevational gradient. Infection probability increased with elevation and canopy cover as it was tightly and inversely correlated with stream-side air temperature. Occupancy patterns suggest varying responses to this disease threat gradient. Two species, L. rheocola and L. serrata, were found over their full historical elevational range (≥1,000 m above sea level [asl]), while L. dayi was not detected above 400 m (formerly known up to 900 m asl) and L. nannotis was not detected above 800 m (formerly known up to 1,200 m asl). Site occupancy probability was negatively related to predicted infection prevalence for L. dayi, L. nannotis, and L. rheocola, but not L. serrata, which appears to now tolerate high fungal burdens. This study highlights the importance of environmental refuges and connectivity across disease risk gradients for the persistence and natural recovery of frogs susceptible to chytridiomycosis. Likewise, in documenting both interspecific variation in recovery rates and intraspecific differences between sites, this study suggests interactions between disease threats and host selection exist that could be manipulated. For example, translocations may be warranted where connectivity is poor or the increase in disease risk is too steep to allow recolonization, combined with assisted selection or use of founders from populations that have already undergone natural selection.
Collapse
Affiliation(s)
- Sara C Bell
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, 4811, Australia
- One Health Research Group, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Werribee, Victoria, 3030, Australia
| | - Geoffrey W Heard
- Institute of Land, Water and Society, Charles Sturt University, Albury, New South Wales, 2640, Australia
- Victorian Department of Environment, Land, Water and Planning, Arthur Rylah Institute for Environmental Research, Heidelberg, Victoria, 3084, Australia
| | - Lee Berger
- One Health Research Group, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Werribee, Victoria, 3030, Australia
| | - Lee F Skerratt
- One Health Research Group, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Werribee, Victoria, 3030, Australia
| |
Collapse
|
36
|
Opedal ØH, Ovaskainen O, Saastamoinen M, Laine AL, van Nouhuys S. Host-plant availability drives the spatiotemporal dynamics of interacting metapopulations across a fragmented landscape. Ecology 2020; 101:e03186. [PMID: 32892363 PMCID: PMC7757193 DOI: 10.1002/ecy.3186] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 07/01/2020] [Accepted: 07/20/2020] [Indexed: 11/26/2022]
Abstract
The dynamics of ecological communities depend partly on species interactions within and among trophic levels. Experimental work has demonstrated the impact of species interactions on the species involved, but it remains unclear whether these effects can also be detected in long‐term time series across heterogeneous landscapes. We analyzed a 19‐yr time series of patch occupancy by the Glanville fritillary butterfly Melitaea cinxia, its specialist parasitoid wasp Cotesia melitaearum, and the specialist fungal pathogen Podosphaera plantaginis infecting Plantago lanceolata, a host plant of the Glanville fritillary. These species share a network of more than 4,000 habitat patches in the Åland islands, providing a metacommunity data set of unique spatial and temporal resolution. To assess the influence of interactions among the butterfly, parasitoid, and mildew on metacommunity dynamics, we modeled local colonization and extinction rates of each species while including or excluding the presence of potentially interacting species in the previous year as predictors. The metapopulation dynamics of all focal species varied both along a gradient in host plant abundance, and spatially as indicated by strong effects of local connectivity. Colonization and to a lesser extent extinction rates depended also on the presence of interacting species within patches. However, the directions of most effects differed from expectations based on previous experimental and modeling work, and the inferred influence of species interactions on observed metacommunity dynamics was limited. These results suggest that although local interactions among the butterfly, parasitoid, and mildew occur, their roles in metacommunity spatiotemporal dynamics are relatively weak. Instead, all species respond to variation in plant abundance, which may in turn fluctuate in response to variation in climate, land use, or other environmental factors.
Collapse
Affiliation(s)
- Øystein H Opedal
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, Helsinki, Finland.,Department of Biology, Lund University, Lund, SE-223 62, Sweden
| | - Otso Ovaskainen
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, Helsinki, Finland.,Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, Trondheim, N-7491, Norway
| | - Marjo Saastamoinen
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, Helsinki, Finland.,Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Anna-Liisa Laine
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, Helsinki, Finland.,Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, CH-8057, Switzerland
| | - Saskya van Nouhuys
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, Helsinki, Finland.,Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, 14853, USA
| |
Collapse
|
37
|
Patterns and drivers of fungal disease communities on Arabica coffee along a management gradient. Basic Appl Ecol 2020. [DOI: 10.1016/j.baae.2020.05.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
|
38
|
Karlsson Green K, Stenberg JA, Lankinen Å. Making sense of Integrated Pest Management (IPM) in the light of evolution. Evol Appl 2020; 13:1791-1805. [PMID: 32908586 PMCID: PMC7463341 DOI: 10.1111/eva.13067] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 07/04/2020] [Accepted: 07/06/2020] [Indexed: 12/21/2022] Open
Abstract
Integrated Pest Management (IPM) is a holistic approach to combat pests (including herbivores, pathogens, and weeds) using a combination of preventive and curative actions, and only applying synthetic pesticides when there is an urgent need. Just as the recent recognition that an evolutionary perspective is useful in medicine to understand and predict interactions between hosts, diseases, and medical treatments, we argue that it is crucial to integrate an evolutionary framework in IPM to develop efficient and reliable crop protection strategies that do not lead to resistance development in herbivores, pathogens, and weeds. Such a framework would not only delay resistance evolution in pests, but also optimize each element of the management and increase the synergies between them. Here, we outline key areas within IPM that would especially benefit from a thorough evolutionary understanding. In addition, we discuss the difficulties and advantages of enhancing communication among research communities rooted in different biological disciplines and between researchers and society. Furthermore, we present suggestions that could advance implementation of evolutionary principles in IPM and thus contribute to the development of sustainable agriculture that is resilient to current and emerging pests.
Collapse
Affiliation(s)
- Kristina Karlsson Green
- Department of Plant Protection BiologySwedish University of Agricultural SciencesAlnarpSweden
| | - Johan A. Stenberg
- Department of Plant Protection BiologySwedish University of Agricultural SciencesAlnarpSweden
| | - Åsa Lankinen
- Department of Plant Protection BiologySwedish University of Agricultural SciencesAlnarpSweden
| |
Collapse
|
39
|
Facilitative priority effects drive parasite assembly under coinfection. Nat Ecol Evol 2020; 4:1510-1521. [PMID: 32868915 DOI: 10.1038/s41559-020-01289-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 07/22/2020] [Indexed: 12/14/2022]
Abstract
Host individuals are often coinfected with diverse parasite assemblages, resulting in complex interactions among parasites within hosts. Within hosts, priority effects occur when the infection sequence alters the outcome of interactions among parasites. Yet, the role of host immunity in this process remains poorly understood. We hypothesized that the host response to the first infection could generate priority effects among parasites, altering the assembly of later-arriving strains during epidemics. We tested this by infecting sentinel host genotypes of Plantago lanceolata with strains of the fungal parasite Podosphaera plantaginis and measuring susceptibility to subsequent infection during experimental and natural epidemics. In these experiments, prior infection by one strain often increased susceptibility to other strains, and these facilitative priority effects altered the structure of parasite assemblages, but this effect depended on host genotype, host population and parasite genotype. Thus, host genotype, spatial structure and priority effects among strains all independently altered parasite assembly. Using a fine-scale survey and sampling of infections on wild hosts in several populations, we then identified a signal of facilitative priority effects, which altered parasite assembly during natural epidemics. Together, these results provide evidence that within-host priority effects of early-arriving strains can drive parasite assembly, with implications for how strain diversity is spatially and temporally distributed during epidemics.
Collapse
|
40
|
Ebert D, Fields PD. Host-parasite co-evolution and its genomic signature. Nat Rev Genet 2020; 21:754-768. [PMID: 32860017 DOI: 10.1038/s41576-020-0269-1] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/16/2020] [Indexed: 01/14/2023]
Abstract
Studies in diverse biological systems have indicated that host-parasite co-evolution is responsible for the extraordinary genetic diversity seen in some genomic regions, such as major histocompatibility (MHC) genes in jawed vertebrates and resistance genes in plants. This diversity is believed to evolve under balancing selection on hosts by parasites. However, the mechanisms that link the genomic signatures in these regions to the underlying co-evolutionary process are only slowly emerging. We still lack a clear picture of the co-evolutionary concepts and of the genetic basis of the co-evolving phenotypic traits in the interacting antagonists. Emerging genomic tools that provide new options for identifying underlying genes will contribute to a fuller understanding of the co-evolutionary process.
Collapse
Affiliation(s)
- Dieter Ebert
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland. .,Wissenschaftskolleg zu Berlin, Berlin, Germany.
| | - Peter D Fields
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland
| |
Collapse
|
41
|
Love Stowell SM, Gagne RB, McWhirter D, Edwards W, Ernest HB. Bighorn Sheep Genetic Structure in Wyoming Reflects Geography and Management. J Wildl Manage 2020. [DOI: 10.1002/jwmg.21882] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Sierra M. Love Stowell
- Wildlife Genomics & Disease Ecology Lab, Department of Veterinary SciencesUniversity of Wyoming 1174 Snowy Range Rd Laramie WY 82070 USA
| | - Roderick B. Gagne
- Wildlife Genomics & Disease Ecology Lab, Department of Veterinary SciencesUniversity of Wyoming 1174 Snowy Range Rd Laramie WY 82070 USA
| | - Doug McWhirter
- Wyoming Game and Fish DepartmentJackson Regional Office 420 N Cache St Jackson WY 830001 USA
| | - William Edwards
- Wyoming Game and Fish DepartmentWildlife Health Laboratory 1174 Snowy Range Rd Laramie WY 82070 USA
| | - Holly B. Ernest
- Wildlife Genomics & Disease Ecology Lab, Department of Veterinary SciencesUniversity of Wyoming 1174 Snowy Range Rd Laramie WY 82070 USA
| |
Collapse
|
42
|
Wilber MQ, Johnson PTJ, Briggs CJ. Disease hotspots or hot species? Infection dynamics in multi-host metacommunities controlled by species identity, not source location. Ecol Lett 2020; 23:1201-1211. [PMID: 32357383 DOI: 10.1111/ele.13518] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 01/29/2020] [Accepted: 03/25/2020] [Indexed: 01/12/2023]
Abstract
Pathogen persistence in host communities is influenced by processes operating at the individual host to landscape-level scale, but isolating the relative contributions of these processes is challenging. We developed theory to partition the influence of host species, habitat patches and landscape connectivity on pathogen persistence within metacommunities of hosts and pathogens. We used this framework to quantify the contributions of host species composition and habitat patch identity on the persistence of an amphibian pathogen across the landscape. By sampling over 11 000 hosts of six amphibian species, we found that a single host species could maintain the pathogen in 91% of observed metacommunities. Moreover, this dominant maintenance species contributed, on average, twice as much to landscape-level pathogen persistence compared to the most influential source patch in a metacommunity. Our analysis demonstrates substantial inequality in how species and patches contribute to pathogen persistence, with important implications for targeted disease management.
Collapse
Affiliation(s)
- Mark Q Wilber
- Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA, 93106, USA
| | - Pieter T J Johnson
- Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, 80309, USA
| | - Cheryl J Briggs
- Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA, 93106, USA
| |
Collapse
|
43
|
Thompson RN, Thompson CP, Pelerman O, Gupta S, Obolski U. Increased frequency of travel in the presence of cross-immunity may act to decrease the chance of a global pandemic. Philos Trans R Soc Lond B Biol Sci 2020; 374:20180274. [PMID: 31056047 DOI: 10.1098/rstb.2018.0274] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The high frequency of modern travel has led to concerns about a devastating pandemic since a lethal pathogen strain could spread worldwide quickly. Many historical pandemics have arisen following pathogen evolution to a more virulent form. However, some pathogen strains invoke immune responses that provide partial cross-immunity against infection with related strains. Here, we consider a mathematical model of successive outbreaks of two strains-a low virulence (LV) strain outbreak followed by a high virulence (HV) strain outbreak. Under these circumstances, we investigate the impacts of varying travel rates and cross-immunity on the probability that a major epidemic of the HV strain occurs, and the size of that outbreak. Frequent travel between subpopulations can lead to widespread immunity to the HV strain, driven by exposure to the LV strain. As a result, major epidemics of the HV strain are less likely, and can potentially be smaller, with more connected subpopulations. Cross-immunity may be a factor contributing to the absence of a global pandemic as severe as the 1918 influenza pandemic in the century since. This article is part of the theme issue 'Modelling infectious disease outbreaks in humans, animals and plants: approaches and important themes'. This issue is linked with the subsequent theme issue 'Modelling infectious disease outbreaks in humans, animals and plants: epidemic forecasting and control'.
Collapse
Affiliation(s)
- R N Thompson
- 1 Mathematical Institute, University of Oxford , Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford OX2 6GG , UK.,2 Department of Zoology, University of Oxford , South Parks Road, Oxford OX1 3PS , UK.,3 Christ Church, University of Oxford , St Aldate's, Oxford OX1 1DP , UK
| | - C P Thompson
- 2 Department of Zoology, University of Oxford , South Parks Road, Oxford OX1 3PS , UK
| | - O Pelerman
- 4 The Chaim Rosenberg School of Jewish Studies, Tel Aviv University , Tel Aviv 69978 , Israel
| | - S Gupta
- 2 Department of Zoology, University of Oxford , South Parks Road, Oxford OX1 3PS , UK
| | - U Obolski
- 2 Department of Zoology, University of Oxford , South Parks Road, Oxford OX1 3PS , UK.,5 School of Public Health , Tel Aviv University, Tel Aviv , Israel.,6 Porter School of the Environment and Earth Sciences, Tel Aviv University , Israel
| |
Collapse
|
44
|
Thompson RN, Brooks-Pollock E. Detection, forecasting and control of infectious disease epidemics: modelling outbreaks in humans, animals and plants. Philos Trans R Soc Lond B Biol Sci 2020; 374:20190038. [PMID: 31056051 DOI: 10.1098/rstb.2019.0038] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The 1918 influenza pandemic is one of the most devastating infectious disease epidemics on record, having caused approximately 50 million deaths worldwide. Control measures, including prohibiting non-essential gatherings as well as closing cinemas and music halls, were applied with varying success and limited knowledge of transmission dynamics. One hundred years later, following developments in the field of mathematical epidemiology, models are increasingly used to guide decision-making and devise appropriate interventions that mitigate the impacts of epidemics. Epidemiological models have been used as decision-making tools during outbreaks in human, animal and plant populations. However, as the subject has developed, human, animal and plant disease modelling have diverged. Approaches have been developed independently for pathogens of each host type, often despite similarities between the models used in these complementary fields. With the increased importance of a One Health approach that unifies human, animal and plant health, we argue that more inter-disciplinary collaboration would enhance each of the related disciplines. This pair of theme issues presents research articles written by human, animal and plant disease modellers. In this introductory article, we compare the questions pertinent to, and approaches used by, epidemiological modellers of human, animal and plant pathogens, and summarize the articles in these theme issues. We encourage future collaboration that transcends disciplinary boundaries and links the closely related areas of human, animal and plant disease epidemic modelling. This article is part of the theme issue 'Modelling infectious disease outbreaks in humans, animals and plants: approaches and important themes'. This issue is linked with the subsequent theme issue 'Modelling infectious disease outbreaks in humans, animals and plants: epidemic forecasting and control'.
Collapse
Affiliation(s)
- Robin N Thompson
- 1 Mathematical Institute, University of Oxford , Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford OX2 6GG , UK.,2 Department of Zoology, University of Oxford , Peter Medawar Building, South Parks Road, Oxford OX1 3SY , UK.,3 Christ Church, University of Oxford , St Aldates, Oxford OX1 1DP , UK
| | - Ellen Brooks-Pollock
- 4 Bristol Veterinary School, University of Bristol , Langford BS40 5DU , UK.,5 National Institute for Health Research, Health Protection Research Unit in Evaluation of Interventions, Bristol Medical School , Bristol BS8 2BN , UK
| |
Collapse
|
45
|
Numminen E, Laine AL. The spread of a wild plant pathogen is driven by the road network. PLoS Comput Biol 2020; 16:e1007703. [PMID: 32231370 PMCID: PMC7108725 DOI: 10.1371/journal.pcbi.1007703] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 01/31/2020] [Indexed: 12/12/2022] Open
Abstract
Spatial analyses of pathogen occurrence in their natural surroundings entail unique opportunities for assessing in vivo drivers of disease epidemiology. Such studies are however confronted by the complexity of the landscape driving epidemic spread and disease persistence. Since relevant information on how the landscape influences epidemiological dynamics is rarely available, simple spatial models of spread are often used. In the current study we demonstrate both how more complex transmission pathways could be incorpoted to epidemiological analyses and how this can offer novel insights into understanding disease spread across the landscape. Our study is focused on Podosphaera plantaginis, a powdery mildew pathogen that transmits from one host plant to another by wind-dispersed spores. Its host populations often reside next to roads and thus we hypothesize that the road network influences the epidemiology of P. plantaginis. To analyse the impact of roads on the transmission dynamics, we consider a spatial dataset on the presence-absence records on the pathogen collected from a fragmented landscape of host populations. Using both mechanistic transmission modeling and statistical modeling with road-network summary statistics as predictors, we conclude the evident role of the road network in the progression of the epidemics: a phenomena which is manifested both in the enhanced transmission along the roads and in infections typically occurring at the central hub locations of the road network. We also demonstrate how the road network affects the spread of the pathogen using simulations. Jointly our results highlight how human alteration of natural landscapes may increase disease spread.
Collapse
Affiliation(s)
- Elina Numminen
- Research Centre for Ecological Change, University of Helsinki, Helsinki, Finland
- Department of Mathematics and Statistics, University of Helsinki, Helsinki, Finland
| | - Anna-Liisa Laine
- Research Centre for Ecological Change, University of Helsinki, Helsinki, Finland
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| |
Collapse
|
46
|
Bellis ES, Kelly EA, Lorts CM, Gao H, DeLeo VL, Rouhan G, Budden A, Bhaskara GB, Hu Z, Muscarella R, Timko MP, Nebie B, Runo SM, Chilcoat ND, Juenger TE, Morris GP, dePamphilis CW, Lasky JR. Genomics of sorghum local adaptation to a parasitic plant. Proc Natl Acad Sci U S A 2020; 117:4243-4251. [PMID: 32047036 PMCID: PMC7049153 DOI: 10.1073/pnas.1908707117] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Host-parasite coevolution can maintain high levels of genetic diversity in traits involved in species interactions. In many systems, host traits exploited by parasites are constrained by use in other functions, leading to complex selective pressures across space and time. Here, we study genome-wide variation in the staple crop Sorghum bicolor (L.) Moench and its association with the parasitic weed Striga hermonthica (Delile) Benth., a major constraint to food security in Africa. We hypothesize that geographic selection mosaics across gradients of parasite occurrence maintain genetic diversity in sorghum landrace resistance. Suggesting a role in local adaptation to parasite pressure, multiple independent loss-of-function alleles at sorghum LOW GERMINATION STIMULANT 1 (LGS1) are broadly distributed among African landraces and geographically associated with S. hermonthica occurrence. However, low frequency of these alleles within S. hermonthica-prone regions and their absence elsewhere implicate potential trade-offs restricting their fixation. LGS1 is thought to cause resistance by changing stereochemistry of strigolactones, hormones that control plant architecture and below-ground signaling to mycorrhizae and are required to stimulate parasite germination. Consistent with trade-offs, we find signatures of balancing selection surrounding LGS1 and other candidates from analysis of genome-wide associations with parasite distribution. Experiments with CRISPR-Cas9-edited sorghum further indicate that the benefit of LGS1-mediated resistance strongly depends on parasite genotype and abiotic environment and comes at the cost of reduced photosystem gene expression. Our study demonstrates long-term maintenance of diversity in host resistance genes across smallholder agroecosystems, providing a valuable comparison to both industrial farming systems and natural communities.
Collapse
Affiliation(s)
- Emily S Bellis
- Department of Biology, The Pennsylvania State University, University Park, PA 16802;
- Arkansas Biosciences Institute, Arkansas State University, State University, AR 72467
- Department of Computer Science, Arkansas State University, State University, AR 72467
| | - Elizabeth A Kelly
- Department of Biology, The Pennsylvania State University, University Park, PA 16802
- Intercollege Graduate Program in Plant Biology, The Pennsylvania State University, University Park, PA 16802
| | - Claire M Lorts
- Department of Biology, The Pennsylvania State University, University Park, PA 16802
| | - Huirong Gao
- Applied Science and Technology, Corteva Agriscience, Johnston, IA 50131
| | - Victoria L DeLeo
- Department of Biology, The Pennsylvania State University, University Park, PA 16802
- Intercollege Graduate Program in Plant Biology, The Pennsylvania State University, University Park, PA 16802
| | - Germinal Rouhan
- Institut Systématique Evolution Biodiversité, Muséum National d'Histoire Naturelle, CNRS, Sorbonne Université, École Pratique des Hautes Études, CP39, 75005 Paris, France
| | - Andrew Budden
- Identification & Naming, Royal Botanic Gardens, Kew, TW9 3AB Richmond, United Kingdom
| | - Govinal B Bhaskara
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712
| | - Zhenbin Hu
- Department of Agronomy, Kansas State University, Manhattan, KS 66506
| | - Robert Muscarella
- Department of Plant Ecology and Evolution, Evolutionary Biology Centre, Uppsala University, SE-75236 Uppsala, Sweden
| | - Michael P Timko
- Department of Biology, University of Virginia, Charlottesville, VA 22904
| | - Baloua Nebie
- West and Central Africa Regional Program, International Crops Research Institute for the Semi-Arid Tropics, BP 320 Bamako, Mali
| | - Steven M Runo
- Department of Biochemistry and Biotechnology, Kenyatta University, Nairobi, Kenya
| | - N Doane Chilcoat
- Applied Science and Technology, Corteva Agriscience, Johnston, IA 50131
| | - Thomas E Juenger
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712
| | - Geoffrey P Morris
- Department of Agronomy, Kansas State University, Manhattan, KS 66506
| | - Claude W dePamphilis
- Department of Biology, The Pennsylvania State University, University Park, PA 16802
| | - Jesse R Lasky
- Department of Biology, The Pennsylvania State University, University Park, PA 16802
| |
Collapse
|
47
|
Russell RE, Tripp DW, Rocke TE. Differential plague susceptibility in species and populations of prairie dogs. Ecol Evol 2019; 9:11962-11971. [PMID: 31695901 PMCID: PMC6822031 DOI: 10.1002/ece3.5684] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 08/28/2019] [Accepted: 09/02/2019] [Indexed: 11/24/2022] Open
Abstract
Laboratory trials conducted over the past decade at U.S. Geological Survey National Wildlife Health Center indicate that wild populations of prairie dogs (Cynomys spp.) display different degrees of susceptibility to experimental challenge with fully virulent Yersinia pestis, the causative agent of plague. We evaluated patterns in prairie dog susceptibility to plague to determine whether the historical occurrence of plague at location of capture was related to survival times of prairie dogs challenged with Y. pestis. We found that black-tailed prairie dogs (Cynomys ludovicianus) from South Dakota (captured prior to the detection of plague in the state), Gunnison's prairie dogs (Cynomys gunnisoni) from Colorado, and Utah prairie dogs (Cynomys parvidens) from Utah were most susceptible to plague. Though the susceptibility of black-tailed prairie dogs in South Dakota compared with western locations supports our hypothesis regarding historical exposure, both Colorado and Utah prairie dogs have a long history of exposure to plague. It is possible that for these populations, genetic isolation/bottle necks have made them more susceptible to plague outbreaks.
Collapse
Affiliation(s)
- Robin E. Russell
- National Wildlife Health CenterU.S. Geological SurveyMadisonWIUSA
| | - Daniel W. Tripp
- Wildlife Health ProgramColorado Parks and WildlifeFort CollinsCOUSA
| | - Tonie E. Rocke
- National Wildlife Health CenterU.S. Geological SurveyMadisonWIUSA
| |
Collapse
|
48
|
Burdon JJ. Lessons from a Life in Time and Space. ANNUAL REVIEW OF PHYTOPATHOLOGY 2019; 57:1-13. [PMID: 31082308 DOI: 10.1146/annurev-phyto-082718-095938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A research career investigating epidemiological and evolutionary patterns in both natural and crop host-pathogen systems emphasizes the need for flexibility in thinking and a willingness to adopt ideas from a wide diversity of subdisciplines. Here, I reflect on the pivotal issues, research areas, and interactions, including the role of science management, that shaped my career in the hope of demonstrating that career paths and collaborations in science can be as diverse and unpredictable as the natural world in which we study our organisms of choice.
Collapse
|
49
|
Numminen E, Vaumourin E, Parratt SR, Poulin L, Laine AL. Variation and correlations between sexual, asexual and natural enemy resistance life-history traits in a natural plant pathogen population. BMC Evol Biol 2019; 19:142. [PMID: 31299905 PMCID: PMC6624897 DOI: 10.1186/s12862-019-1468-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 06/26/2019] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Understanding the mechanisms by which diversity is maintained in pathogen populations is critical for epidemiological predictions. Life-history trade-offs have been proposed as a hypothesis for explaining long-term maintenance of variation in pathogen populations, yet the empirical evidence supporting trade-offs has remained mixed. This is in part due to the challenges of documenting successive pathogen life-history stages in many pathosystems. Moreover, little is understood of the role of natural enemies of pathogens on their life-history evolution. RESULTS We characterize life-history-trait variation and possible trade-offs in fungal pathogen Podosphaera plantaginis infecting the host plant Plantago lanceolata. We measured the timing of both asexual and sexual stages, as well as resistance to a hyperparasite of seven pathogen strains that vary in their prevalence in nature. We find significant variation among the strains in their life-history traits that constitute the infection cycle, but no evidence for trade-offs among pathogen development stages, apart from fast pathogen growth coninciding with fast hyperparasite growth. Also, the seemingly least fit pathogen strain was the most prevalent in the nature. CONCLUSIONS We conclude that in the nature environmental variation, and interactions with the antagonists of pathogens themselves may maintain variation in pathogen populations.
Collapse
Affiliation(s)
- Elina Numminen
- Department of Biosciences, University of Helsinki, Viikinkaari 1, PO Box 65, FI-00014, Helsinki, Finland.
| | - Elise Vaumourin
- Department of Biosciences, University of Helsinki, Viikinkaari 1, PO Box 65, FI-00014, Helsinki, Finland
| | - Steven R Parratt
- Department of Biosciences, University of Helsinki, Viikinkaari 1, PO Box 65, FI-00014, Helsinki, Finland.,University of Liverpool, Institute of Integrative Biology, Liverpool, L69 3BX, UK
| | - Lucie Poulin
- Department of Biosciences, University of Helsinki, Viikinkaari 1, PO Box 65, FI-00014, Helsinki, Finland.,Université de Nantes, Faculté des Sciences et des Techniques, Laboratoire de Biologie et de Pathologie Végétales (LBPV), EA 1157, SFR 4207 QUASAV, 2, rue de la Houssinière, BP 92 208, F-44322, Nantes Cedex 3, France
| | - Anna-Liisa Laine
- Department of Biosciences, University of Helsinki, Viikinkaari 1, PO Box 65, FI-00014, Helsinki, Finland.,Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| |
Collapse
|
50
|
Laine AL, Barrès B, Numminen E, Siren JP. Variable opportunities for outcrossing result in hotspots of novel genetic variation in a pathogen metapopulation. eLife 2019; 8:47091. [PMID: 31210640 PMCID: PMC6667214 DOI: 10.7554/elife.47091] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 06/18/2019] [Indexed: 11/17/2022] Open
Abstract
Many pathogens possess the capacity for sex through outcrossing, despite being able to reproduce also asexually and/or via selfing. Given that sex is assumed to come at a cost, these mixed reproductive strategies typical of pathogens have remained puzzling. While the ecological and evolutionary benefits of outcrossing are theoretically well-supported, support for such benefits in pathogen populations are still scarce. Here, we analyze the epidemiology and genetic structure of natural populations of an obligate fungal pathogen, Podosphaera plantaginis. We find that the opportunities for outcrossing vary spatially. Populations supporting high levels of coinfection –a prerequisite of sex – result in hotspots of novel genetic diversity. Pathogen populations supporting coinfection also have a higher probability of surviving winter. Jointly our results show that outcrossing has direct epidemiological consequences as well as a major impact on pathogen population genetic diversity, thereby providing evidence of ecological and evolutionary benefits of outcrossing in pathogens. The existence of sex – broadly defined as the coming together of genes from different individuals – is one of the big evolutionary puzzles. Reproduction allows an organism to pass on its genes to future generations. However, while asexual and self-fertilizing individuals transmit all of their genes to their offspring, individuals that reproduce through sex transmit only half of their genome. This is considered the cost of sex. Many pathogens reproduce through sex, despite often also being able to reproduce asexually or by self-fertilization. Typically a pre-requisite of sex in pathogens is for at least two different strains to infect the same host. Aside from this limitation, little is known about when, where and why pathogens have sex. It has been tricky to study due to the microscopic size of pathogens and the difficulties of identifying different sexes. Moreover, sexual reproduction may be triggered by environmental cues that are difficult to mimic under controlled experimental conditions. Are there any benefits associated with pathogen sex? To find out, Laine et al. analyzed data collected over the course of four years from thousands of populations of a powdery mildew fungus that infected plants across the Åland islands. This revealed that the opportunities for pathogen sex vary in different locations. Areas where multiple strains of the fungus commonly infect the same plants result in hotspots of new genetic diversity. These mixed populations are also more likely to survive winter. This demonstrates the potential for pathogen sexual reproduction to provide an ecological benefit. Identifying areas and populations where pathogens have sex can help to identify when and where new strains are most likely to emerge. In the future, studies that use similar methods to Laine et al. could help to predict where infections and diseases are highly likely to arise.
Collapse
Affiliation(s)
- Anna-Liisa Laine
- Research Centre for Ecological Change, Organismal and Evolutionary Biology, University of Helsinki, Helsinki, Finland.,Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse, Switzerland
| | - Benoit Barrès
- Research Centre for Ecological Change, Organismal and Evolutionary Biology, University of Helsinki, Helsinki, Finland
| | - Elina Numminen
- Research Centre for Ecological Change, Organismal and Evolutionary Biology, University of Helsinki, Helsinki, Finland
| | - Jukka P Siren
- Research Centre for Ecological Change, Organismal and Evolutionary Biology, University of Helsinki, Helsinki, Finland.,Helsinki Institute for Information Technology, Department of Computer Science, Aalto University, Espoo, Finland
| |
Collapse
|