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Le Clec’h W, Chevalier FD, McDew-White M, Menon V, Arya GA, Anderson TJ. Genetic architecture of transmission stage production and virulence in schistosome parasites. Virulence 2021; 12:1508-1526. [PMID: 34167443 PMCID: PMC8237990 DOI: 10.1080/21505594.2021.1932183] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 05/06/2021] [Accepted: 05/14/2021] [Indexed: 12/30/2022] Open
Abstract
Both theory and experimental data from pathogens suggest that the production of transmission stages should be strongly associated with virulence, but the genetic bases of parasite transmission/virulence traits are poorly understood. The blood fluke Schistosoma mansoni shows extensive variation in numbers of cercariae larvae shed and in their virulence to infected snail hosts, consistent with expected trade-offs between parasite transmission and virulence. We crossed schistosomes from two populations that differ 8-fold in cercarial shedding and in their virulence to Biomphalaria glabrata snail hosts, and determined four-week cercarial shedding profiles in F0 parents, F1 parents and 376 F2 progeny from two independent crosses in inbred snails. Sequencing and linkage analysis revealed that cercarial production is polygenic and controlled by five QTLs (i.e. Quantitative Trait Loci). These QTLs act additively, explaining 28.56% of the phenotypic variation. These results demonstrate that the genetic architecture of key traits relevant to schistosome ecology can be dissected using classical linkage mapping approaches.
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Affiliation(s)
- Winka Le Clec’h
- Texas Biomedical Research Institute, San Antonio, Texas, USA
| | | | | | - Vinay Menon
- Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Grace-Ann Arya
- Texas Biomedical Research Institute, San Antonio, Texas, USA
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Kranse O, Beasley H, Adams S, Pires-daSilva A, Bell C, Lilley CJ, Urwin PE, Bird D, Miska E, Smant G, Gheysen G, Jones J, Viney M, Abad P, Maier TR, Baum TJ, Siddique S, Williamson V, Akay A, Eves-van den Akker S. Toward genetic modification of plant-parasitic nematodes: delivery of macromolecules to adults and expression of exogenous mRNA in second stage juveniles. G3-GENES GENOMES GENETICS 2021; 11:6135037. [PMID: 33585878 PMCID: PMC8022973 DOI: 10.1093/g3journal/jkaa058] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 10/30/2020] [Indexed: 12/16/2022]
Abstract
Plant-parasitic nematodes are a continuing threat to food security, causing an estimated 100 billion USD in crop losses each year. The most problematic are the obligate sedentary endoparasites (primarily root knot nematodes and cyst nematodes). Progress in understanding their biology is held back by a lack of tools for functional genetics: forward genetics is largely restricted to studies of natural variation in populations and reverse genetics is entirely reliant on RNA interference. There is an expectation that the development of functional genetic tools would accelerate the progress of research on plant-parasitic nematodes, and hence the development of novel control solutions. Here, we develop some of the foundational biology required to deliver a functional genetic tool kit in plant-parasitic nematodes. We characterize the gonads of male Heterodera schachtii and Meloidogyne hapla in the context of spermatogenesis. We test and optimize various methods for the delivery, expression, and/or detection of exogenous nucleic acids in plant-parasitic nematodes. We demonstrate that delivery of macromolecules to cyst and root knot nematode male germlines is difficult, but possible. Similarly, we demonstrate the delivery of oligonucleotides to root knot nematode gametes. Finally, we develop a transient expression system in plant-parasitic nematodes by demonstrating the delivery and expression of exogenous mRNA encoding various reporter genes throughout the body of H. schachtii juveniles using lipofectamine-based transfection. We anticipate these developments to be independently useful, will expedite the development of genetic modification tools for plant-parasitic nematodes, and ultimately catalyze research on a group of nematodes that threaten global food security.
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Affiliation(s)
- Olaf Kranse
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, UK
| | - Helen Beasley
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, UK
| | - Sally Adams
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | | | - Christopher Bell
- Centre for Plant Sciences, School of Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Catherine J Lilley
- Centre for Plant Sciences, School of Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Peter E Urwin
- Centre for Plant Sciences, School of Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - David Bird
- Entomology and Plant Pathology, NC State University, Raleigh, NC 27695-7613, USA
| | - Eric Miska
- Wellcome Trust/Cancer Research UK Gurdon Institute and Department of Genetics, University of Cambridge, Cambridge CB2 1QN, UK
| | - Geert Smant
- Laboratory of Nematology, Department of Plant Sciences, Wageningen University & Research, 6708 PB Wageningen, The Netherlands
| | - Godelieve Gheysen
- Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, 9000 Ghent, Belgium
| | - John Jones
- Cell & Molecular Sciences Department, The James Hutton Institute, Dundee, DD2 5DA, UK.,School of Biology, Biomedical Sciences Research Complex, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK
| | - Mark Viney
- Department of Evolution, Ecology and Behaviour, University of Liverpool, Liverpool L69 7ZB, UK
| | - Pierre Abad
- INRAE, Université Côte d'Azur, CNRS, ISA, F-06903 Sophia Antipolis, France
| | - Thomas R Maier
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA 50011, USA
| | - Thomas J Baum
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA 50011, USA
| | - Shahid Siddique
- Department of Entomology and Nematology, University of California, Davis, Davis, CA 95616, USA
| | - Valerie Williamson
- Department of Plant Pathology, University of California, Davis, Davis, CA 95616, USA
| | - Alper Akay
- Biomedical Research Centre, School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
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Li C, Wang J, You J, Wang X, Liu B, Abe J, Kong F, Wang C. Quantitative trait loci mapping of Meloidogyne incognita and M. hapla resistance in a recombinant inbred line population of soybean. NEMATOLOGY 2018. [DOI: 10.1163/15685411-00003157] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Summary
A recombinant inbred line population of soybean (Glycine max) was utilised to identify the quantitative trait loci (QTLs) determining the response to infection by two root-knot nematode species, Meloidogyne incognita and M. hapla, in glasshouse assays. QTL analysis detected seven major and four minor QTLs on seven soybean chromosomes ((Chrs) 1, 7, 8, 10, 14, 18, 20) explaining 6-41% phenotypic variance (PVE) for M. incognita root response and nematode reproduction. Three of the major QTLs, on Chrs 7, 10 and 18, were confirmed in previous reports and two major QTLs on Chrs 14 and 20 were detected for the first time. The QTL analysis with M. hapla provides the first report of a major QTL region mapped on Chr 7, explaining 70-82% PVE in M. hapla root response and nematode reproduction. These novel identified QTLs with flanking markers will be helpful in marker-assisted breeding for nematode resistance in soybean.
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Affiliation(s)
- Chunjie Li
- 1Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, P. R. China
| | - Jialin Wang
- 2Key Laboratory of Molecular Design Breeding, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, P. R. China
| | - Jia You
- 1Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, P. R. China
| | - Xinpeng Wang
- 1Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, P. R. China
| | - Baohui Liu
- 2Key Laboratory of Molecular Design Breeding, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, P. R. China
| | - Jun Abe
- 3Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan
| | - Fanjiang Kong
- 2Key Laboratory of Molecular Design Breeding, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, P. R. China
- 4School of Life Sciences, Guangzhou University, Guangzhou 510006, P. R. China
| | - Congli Wang
- 1Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, P. R. China
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Guo Y, Fudali S, Gimeno J, DiGennaro P, Chang S, Williamson VM, Bird DM, Nielsen DM. Networks Underpinning Symbiosis Revealed Through Cross-Species eQTL Mapping. Genetics 2017; 206:2175-2184. [PMID: 28642272 PMCID: PMC5560814 DOI: 10.1534/genetics.117.202531] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Accepted: 06/09/2017] [Indexed: 12/13/2022] Open
Abstract
Organisms engage in extensive cross-species molecular dialog, yet the underlying molecular actors are known for only a few interactions. Many techniques have been designed to uncover genes involved in signaling between organisms. Typically, these focus on only one of the partners. We developed an expression quantitative trait locus (eQTL) mapping-based approach to identify cause-and-effect relationships between genes from two partners engaged in an interspecific interaction. We demonstrated the approach by assaying expression of 98 isogenic plants (Medicago truncatula), each inoculated with a genetically distinct line of the diploid parasitic nematode Meloidogyne hapla With this design, systematic differences in gene expression across host plants could be mapped to genetic polymorphisms of their infecting parasites. The effects of parasite genotypes on plant gene expression were often substantial, with up to 90-fold (P = 3.2 × 10-52) changes in expression levels caused by individual parasite loci. Mapped loci included a number of pleiotropic sites, including one 87-kb parasite locus that modulated expression of >60 host genes. The 213 host genes identified were substantially enriched for transcription factors. We distilled higher-order connections between polymorphisms and genes from both species via network inference. To replicate our results and test whether effects were conserved across a broader host range, we performed a confirmatory experiment using M. hapla-infected tomato. This revealed that homologous genes were similarly affected. Finally, to validate the broader utility of cross-species eQTL mapping, we applied the strategy to data from a Salmonella infection study, successfully identifying polymorphisms in the human genome affecting bacterial expression.
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Affiliation(s)
- Yuelong Guo
- Bioinformatics Research Center, North Carolina State University, Raleigh, North Carolina 27695
| | - Sylwia Fudali
- Department of Plant Pathology, University of California, Davis, California 95616
| | - Jacinta Gimeno
- Department of Plant Pathology, University of California, Davis, California 95616
| | - Peter DiGennaro
- Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina 27695
| | - Stella Chang
- Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina 27695
| | - Valerie M Williamson
- Department of Plant Pathology, University of California, Davis, California 95616
| | - David McK Bird
- Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina 27695
| | - Dahlia M Nielsen
- Bioinformatics Research Center, North Carolina State University, Raleigh, North Carolina 27695
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina 27695
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Thomas A, Carbone I, Cohen Y, Ojiambo PS. Occurrence and Distribution of Mating Types of Pseudoperonospora cubensis in the United States. PHYTOPATHOLOGY 2017; 107:313-321. [PMID: 27841962 DOI: 10.1094/phyto-06-16-0236-r] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
During the past two decades, a resurgence of cucurbit downy mildew has occurred around the world, resulting in severe disease epidemics. In the United States, resurgence of the disease occurred in 2004 and several hypotheses, including introduction of a new genetic recombinant or pathotype of the pathogen, have been suggested as potential causes for this resurgence. Occurrence and distribution of mating types of Pseudoperonospora cubensis in the United States were investigated using 40 isolates collected from cucurbits across 11 states from 2005 to 2013. Pairing of unknown isolates with known mating-type tester strains on detached leaves of cantaloupe or cucumber resulted in oospore formation 8 to 10 days after inoculation. Isolates differed in their ability to form oospores across all coinoculation pairings, with oospore numbers ranging from 280 to 1,000 oospores/cm2 of leaf tissue. Oospores were hyaline to golden-yellow, spherical, and approximately 36 μm in diameter. Of the 40 isolates tested, 24 were found to be of the A1 mating type, while 16 were of the A2 mating type. Mating type was significantly (P < 0.0001) associated with host type, whereby all isolates collected from cucumber were of the A1 mating type, while isolates from squash and watermelon were of the A2 mating type. Similarly, mating type was significantly (P = 0.0287) associated with geographical region, where isolates from northern-tier states of Michigan, New Jersey, New York, and Ohio were all A1, while isolates belonging to either A1 or A2 mating type were present in equal proportions in southern-tier states of Alabama, Florida, Georgia, North Carolina, South Carolina, and Texas. Viability assays showed that oospores were viable and, on average, approximately 40% of the oospores produced were viable as determined by the plasmolysis method. This study showed that A1 and A2 mating types of P. cubensis are present and the pathogen could potentially reproduce sexually in cucurbits within the United States. In addition, the production of viable oospores reported in this study suggests that oospores could have an important role in the biology of P. cubensis and could potentially influence the epidemiology of cucurbit downy mildew in the United States.
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Affiliation(s)
- Anna Thomas
- First, second, and fourth authors: Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh 27695; and third author: Faculty of Life Sciences, Bar-Ilan University, Ramat Gan 52100, Israel
| | - Ignazio Carbone
- First, second, and fourth authors: Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh 27695; and third author: Faculty of Life Sciences, Bar-Ilan University, Ramat Gan 52100, Israel
| | - Yigal Cohen
- First, second, and fourth authors: Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh 27695; and third author: Faculty of Life Sciences, Bar-Ilan University, Ramat Gan 52100, Israel
| | - Peter S Ojiambo
- First, second, and fourth authors: Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh 27695; and third author: Faculty of Life Sciences, Bar-Ilan University, Ramat Gan 52100, Israel
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Keinath AP. Utility of a Cucumber Plant Bioassay to Assess Fungicide Efficacy Against Pseudoperonospora cubensis. PLANT DISEASE 2016; 100:490-499. [PMID: 30694139 DOI: 10.1094/pdis-05-15-0499-re] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Over a dozen fungicides are registered in the United States to manage cucurbit downy mildew caused by Pseudoperonospora cubensis. Efficacy varies greatly among them, due, in part, to reduced sensitivity to some fungicides in some pathogen populations. The objective of this study was to determine whether fungicide efficacy could be assessed using fungicide-treated cucumber (Cucumis sativus) exposed to natural inoculum for a brief period. Potted cucumber plants were treated with water or 1 of 13 fungicides registered to control cucurbit downy mildew. One day later, they were placed in a field among cucumber plants that had symptoms and signs of downy mildew. After a 48-h exposure to P. cubensis, potted plants were moved to a growth chamber held at day and night temperatures of 21 and 18°C, respectively, and 50% relative humidity. Severity (leaf area with symptoms) of downy mildew was rated 5 and 7 days later. The assay was done eight times, twice each in July and October 2013 and 2014. Year, season, trial, and interactions among these factors affected downy mildew development. Severity at 7 days on plants treated with mandipropamid, azoxystrobin, dimethomorph, cymoxanil, fluopicolide, and propamocarb was not significantly different from the water control treatment in eight, five, three, three, two, and two of eight bioassays, respectively. Severity on plants treated with cyazofamid, fluazinam, mancozeb + zoxamide, mancozeb, chlorothalonil, and ametoctradin + dimethomorph was less than on plants treated with water in all bioassays. These six fungicides should be effective when applied early in the season to prevent initial infections. Cyazofamid and mancozeb + zoxamide prevented an increase in severity between rating times. In conclusion, the assay consistently detected resistance to mandipropamid and azoxystrobin and demonstrated the efficacy of six other fungicides.
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Affiliation(s)
- Anthony P Keinath
- Coastal Research and Education Center, Clemson University, Charleston, SC, 29414-5329
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Ojiambo PS, Gent DH, Quesada-Ocampo LM, Hausbeck MK, Holmes GJ. Epidemiology and population biology of Pseudoperonospora cubensis: a model system for management of downy mildews. ANNUAL REVIEW OF PHYTOPATHOLOGY 2015; 53:223-246. [PMID: 26002291 DOI: 10.1146/annurev-phyto-080614-120048] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The resurgence of cucurbit downy mildew has dramatically influenced production of cucurbits and disease management systems at multiple scales. Long-distance dispersal is a fundamental aspect of epidemic development that influences the timing and extent of outbreaks of cucurbit downy mildew. The dispersal potential of Pseudoperonospora cubensis appears to be limited primarily by sporangia production in source fields and availability of susceptible hosts and less by sporangia survival during transport. Uncertainty remains regarding the role of locally produced inoculum in disease outbreaks, but evidence suggests multiple sources of primary inoculum could be important. Understanding pathogen diversity and population differentiation is a critical aspect of disease management and an active research area. Underpinning advances in our understanding of pathogen biology and disease management has been the research capacity and coordination of stakeholders, scientists, and extension personnel. Concepts and approaches developed in this pathosystem can guide future efforts when responding to incursions of new or reemerging downy mildew pathogens.
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Affiliation(s)
- Peter S Ojiambo
- Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina 27695; ,
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