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Molinero-Ruiz L. Sustainable and efficient control of sunflower downy mildew by means of genetic resistance: a review. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2022; 135:3757-3771. [PMID: 35084515 DOI: 10.1007/s00122-022-04038-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 01/12/2022] [Indexed: 06/14/2023]
Abstract
The breeding of sunflower (Helianthus annuus L.) for resistance to downy mildew (caused by the oomycete Plasmopara halstedii Farl. Berl. & de Toni) is reviewed in this work under the scope of its sustainability and efficiency. When sunflower turned into an oilseed crop, resistance to the disease was included in its initial breeding strategies. Subsequent development of genomic tools allowed a significant expansion of the knowledge on the diversity of its genetic resistance and its application to the genetic control of the disease. Simultaneously to genetic improvements, and as a consequence of the close interaction between the pathogen and its host plant, an enormous variety of pathotypes has been described in all the sunflower-growing areas worldwide. Thus, the genetic control of sunflower downy mildew is an active research field subjected to continuous evolution and challenge. In practice, genetic resistance constitutes the base tier of Integrated Pest Management against sunflower downy mildew. The second tier is composed of elements related to crop management: rotation, removal of volunteer plants, sowing date, tillage. Biological control alternatives and resistance inducers could also provide additional restraint. Finally, the top tier includes chemical treatments that should only be used when necessary and if the more basal Integrated Pest Management elements fail to keep pathogen populations under the economic threshold.
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Affiliation(s)
- L Molinero-Ruiz
- Institute for Sustainable Agriculture (IAS), Spanish National Research Council (CSIC), Alameda del Obispo s/n, 14004, Córdoba, Spain.
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Elameen A, de Labrouhe DT, Bret-Mestries E, Delmotte F. Spatial Genetic Structure and Pathogenic Race Composition at the Field Scale in the Sunflower Downy Mildew Pathogen, Plasmopara halstedii. J Fungi (Basel) 2022; 8:1084. [PMID: 36294648 PMCID: PMC9605284 DOI: 10.3390/jof8101084] [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: 06/22/2022] [Revised: 09/27/2022] [Accepted: 10/11/2022] [Indexed: 11/22/2022] Open
Abstract
Yield losses in sunflower crops caused by Plasmopara halstedii can be up to 100%, depending on the cultivar susceptibility, environmental conditions, and virulence of the pathogen population. The aim of this study was to investigate the genetic and phenotypic structure of a sunflower downy mildew agent at the field scale. The genetic diversity of 250 P. halstedii isolates collected from one field in southern France was assessed using single-nucleotide polymorphisms (SNPs) and single sequence repeats (SSR). A total of 109 multilocus genotypes (MLG) were identified among the 250 isolates collected in the field. Four genotypes were repeated more than 20 times and spatially spread over the field. Estimates of genetic relationships among P. halstedii isolates using principal component analysis and a Bayesian clustering approach demonstrated that the isolates are grouped into two main genetic clusters. A high level of genetic differentiation among clusters was detected (FST = 0.35), indicating overall limited exchange between them, but our results also suggest that recombination between individuals of these groups is not rare. Genetic clusters were highly related to pathotypes, as previously described for this pathogen species. Eight different races were identified (100, 300, 304, 307, 703, 704, 707, and 714), with race 304 being predominant and present at most of the sites. The co-existence of multiple races at the field level is a new finding that could have important implications for the management of sunflower downy mildew. These data provide the first population-wide picture of the genetic structure of P. halstedii at a fine spatial scale.
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Affiliation(s)
- Abdelhameed Elameen
- NIBIO, Norwegian Institute of Bioeconomy Research, Division of Biotechnology and Plant Health, N-1431 Ås, Norway
| | | | | | - Francois Delmotte
- INRAE, Bordeaux Sciences Agro, ISVV, SAVE, 33140 Villenave d’Ornon, France
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Gómez-Pérez D, Kemen E. Predicting Lifestyle from Positive Selection Data and Genome Properties in Oomycetes. Pathogens 2021; 10:807. [PMID: 34202069 PMCID: PMC8308905 DOI: 10.3390/pathogens10070807] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/19/2021] [Accepted: 06/21/2021] [Indexed: 11/30/2022] Open
Abstract
As evidenced in parasitism, host and niche shifts are a source of genomic and phenotypic diversification. Exemplary is a reduction in the core metabolism as parasites adapt to a particular host, while the accessory genome often maintains a high degree of diversification. However, selective pressures acting on the genome of organisms that have undergone recent lifestyle or host changes have not been fully investigated. Here, we developed a comparative genomics approach to study underlying adaptive trends in oomycetes, a eukaryotic phylum with a wide and diverse range of economically important plant and animal parasitic lifestyles. Our analysis reveals converging evolution on biological processes for oomycetes that have similar lifestyles. Moreover, we find that certain functions, in particular carbohydrate metabolism, transport, and signaling, are important for host and environmental adaptation in oomycetes. Given the high correlation between lifestyle and genome properties in our oomycete dataset, together with the known convergent evolution of fungal and oomycete genomes, we developed a model that predicts plant pathogenic lifestyles with high accuracy based on functional annotations. These insights into how selective pressures correlate with lifestyle may be crucial to better understand host/lifestyle shifts and their impact on the genome.
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Affiliation(s)
| | - Eric Kemen
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, 72074 Tübingen, Germany;
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Gilley MA, Gulya TJ, Seiler GJ, Underwood W, Hulke BS, Misar CG, Markell SG. Determination of Virulence Phenotypes of Plasmopara halstedii in the United States. PLANT DISEASE 2020; 104:2823-2831. [PMID: 32955406 DOI: 10.1094/pdis-10-19-2063-re] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Downy mildew, caused by Plasmopara halstedii (Farl.) Berl. and de Toni, is an economically important disease in cultivated sunflowers, Helianthus annuus L. Resistance genes incorporated into commercial hybrids are used as an effective disease management tool, but the duration of effectiveness is limited as virulence evolves in the pathogen population. A comprehensive assessment of pathogen virulence was conducted in 2014 and 2015 in the U.S. Great Plains states of North Dakota and South Dakota, where approximately 75% of the U.S. sunflower is produced annually. The virulence phenotypes (and races) of 185 isolates were determined using the U.S. standard set of nine differentials. Additionally, the virulence phenotypes of 61 to 185 isolates were determined on 13 additional lines that have been used to evaluate pathogen virulence in North America and/or internationally. Although widespread virulence was identified on several genes, new virulence was identified on the Pl8 resistance gene, and no virulence was observed on the PlArg, Pl15, Pl17 and Pl18 genes. Results of this study suggest that three additional lines should be used as differentials and agree with previous studies that six lines proposed as differentials should be used in two internationally accepted differential sets. For effective disease management using genetic resistance, it is critical that virulence data be relevant and timely. This is best accomplished when pathogen virulence is determined frequently and by using genetic lines containing resistance genes actively incorporated into commercial cultivars.
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Affiliation(s)
- Michelle A Gilley
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58102
| | | | | | | | | | | | - Samuel G Markell
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58102
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Shamim M, Kumar P, Kumar RR, Kumar M, Kumar RR, Singh KN. Assessing Fungal Biodiversity Using Molecular Markers. Fungal Biol 2017. [DOI: 10.1007/978-3-319-34106-4_15] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Rivera Y, Salgado-Salazar C, Gulya TJ, Crouch JA. Newly Emerged Populations of Plasmopara halstedii Infecting Rudbeckia Exhibit Unique Genotypic Profiles and Are Distinct from Sunflower-Infecting Strains. PHYTOPATHOLOGY 2016; 106:752-761. [PMID: 27003506 DOI: 10.1094/phyto-12-15-0335-r] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The oomycete Plasmopara halstedii emerged at the onset of the 21st century as a destructive new pathogen causing downy mildew disease of ornamental Rudbeckia fulgida (rudbeckia) in the United States. The pathogen is also a significant global problem of sunflower (Helianthus annuus) and is widely regarded as the cause of downy mildew affecting 35 Asteraceae genera. To determine whether rudbeckia and sunflower downy mildew are caused by the same genotypes, population genetic and phylogenetic analyses were performed. A draft genome assembly of a P. halstedii isolate from sunflower was generated and used to design 15 polymorphic simple sequence repeat (SSR) markers. SSRs and two sequenced phylogenetic markers measured differentiation between 232 P. halstedii samples collected from 1883 to 2014. Samples clustered into two main groups, corresponding to host origin. Sunflower-derived samples separated into eight admixed subclusters, and rudbeckia-derived samples further separated into three subclusters. Pre-epidemic rudbeckia samples clustered separately from modern strains. Despite the observed genetic distinction based on host origin, P. halstedii from rudbeckia could infect sunflower, and exhibited the virulence phenotype of race 734. These data indicate that the newly emergent pathogen populations infecting commercial rudbeckia are a different species from sunflower-infecting strains, notwithstanding cross-infectivity, and genetically distinct from pre-epidemic populations infecting native rudbeckia hosts.
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Affiliation(s)
- Yazmín Rivera
- First, second, and fourth author: U.S. Department of Agriculture-Agriculture Research Service (USDA-ARS), Systematic Mycology and Microbiology Laboratory, 10300 Baltimore Avenue, Beltsville, MD 20705; first and second authors: Department of Plant Biology and Pathology, Rutgers University, 59 Dudley Road, New Brunswick, NJ 08906; and third author: USDA-ARS, Sunflower and Plant Biology Research Unit, 1605 Albrecht Boulevard North, Fargo, ND 58102 (retired)
| | - Catalina Salgado-Salazar
- First, second, and fourth author: U.S. Department of Agriculture-Agriculture Research Service (USDA-ARS), Systematic Mycology and Microbiology Laboratory, 10300 Baltimore Avenue, Beltsville, MD 20705; first and second authors: Department of Plant Biology and Pathology, Rutgers University, 59 Dudley Road, New Brunswick, NJ 08906; and third author: USDA-ARS, Sunflower and Plant Biology Research Unit, 1605 Albrecht Boulevard North, Fargo, ND 58102 (retired)
| | - Thomas J Gulya
- First, second, and fourth author: U.S. Department of Agriculture-Agriculture Research Service (USDA-ARS), Systematic Mycology and Microbiology Laboratory, 10300 Baltimore Avenue, Beltsville, MD 20705; first and second authors: Department of Plant Biology and Pathology, Rutgers University, 59 Dudley Road, New Brunswick, NJ 08906; and third author: USDA-ARS, Sunflower and Plant Biology Research Unit, 1605 Albrecht Boulevard North, Fargo, ND 58102 (retired)
| | - Jo Anne Crouch
- First, second, and fourth author: U.S. Department of Agriculture-Agriculture Research Service (USDA-ARS), Systematic Mycology and Microbiology Laboratory, 10300 Baltimore Avenue, Beltsville, MD 20705; first and second authors: Department of Plant Biology and Pathology, Rutgers University, 59 Dudley Road, New Brunswick, NJ 08906; and third author: USDA-ARS, Sunflower and Plant Biology Research Unit, 1605 Albrecht Boulevard North, Fargo, ND 58102 (retired)
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Gascuel Q, Bordat A, Sallet E, Pouilly N, Carrere S, Roux F, Vincourt P, Godiard L. Effector Polymorphisms of the Sunflower Downy Mildew Pathogen Plasmopara halstedii and Their Use to Identify Pathotypes from Field Isolates. PLoS One 2016; 11:e0148513. [PMID: 26845339 PMCID: PMC4742249 DOI: 10.1371/journal.pone.0148513] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 01/19/2016] [Indexed: 01/23/2023] Open
Abstract
The obligate biotroph oomycete Plasmopara halstedii causes downy mildew on sunflower crop, Helianthus annuus. The breakdown of several Pl resistance genes used in sunflower hybrids over the last 25 years came along with the appearance of new Pl. halstedii isolates showing modified virulence profiles. In oomycetes, two classes of effector proteins, key players of pathogen virulence, are translocated into the host: RXLR and CRN effectors. We identified 54 putative CRN or RXLR effector genes from transcriptomic data and analyzed their genetic diversity in seven Pl. halstedii pathotypes representative of the species variability. Pl. halstedii effector genes were on average more polymorphic at both the nucleic and protein levels than random non-effector genes, suggesting a potential adaptive dynamics of pathogen virulence over the last 25 years. Twenty-two KASP (Competitive Allele Specific PCR) markers designed on polymorphic effector genes were genotyped on 35 isolates belonging to 14 Pl. halstedii pathotypes. Polymorphism analysis based on eight KASP markers aims at proposing a determination key suitable to classify the eight multi-isolate pathotypes into six groups. This is the first report of a molecular marker set able to discriminate Pl. halstedii pathotypes based on the polymorphism of pathogenicity effectors. Compared to phenotypic tests handling living spores used until now to discriminate Pl. halstedii pathotypes, this set of molecular markers constitutes a first step in faster pathotype diagnosis of Pl. halstedii isolates. Hence, emerging sunflower downy mildew isolates could be more rapidly characterized and thus, assessment of plant resistance breakdown under field conditions should be improved.
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Affiliation(s)
- Quentin Gascuel
- Institut National de la Recherche Agronomique, INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), Unité Mixte de Recherches UMR441, F-31326 Castanet-Tolosan, France
- Centre National de la Recherche Scientifique, CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), Unité Mixte de Recherches UMR2594, F-31326 Castanet-Tolosan, France
| | - Amandine Bordat
- Institut National de la Recherche Agronomique, INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), Unité Mixte de Recherches UMR441, F-31326 Castanet-Tolosan, France
- Centre National de la Recherche Scientifique, CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), Unité Mixte de Recherches UMR2594, F-31326 Castanet-Tolosan, France
| | - Erika Sallet
- Institut National de la Recherche Agronomique, INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), Unité Mixte de Recherches UMR441, F-31326 Castanet-Tolosan, France
- Centre National de la Recherche Scientifique, CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), Unité Mixte de Recherches UMR2594, F-31326 Castanet-Tolosan, France
| | - Nicolas Pouilly
- Institut National de la Recherche Agronomique, INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), Unité Mixte de Recherches UMR441, F-31326 Castanet-Tolosan, France
- Centre National de la Recherche Scientifique, CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), Unité Mixte de Recherches UMR2594, F-31326 Castanet-Tolosan, France
| | - Sébastien Carrere
- Institut National de la Recherche Agronomique, INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), Unité Mixte de Recherches UMR441, F-31326 Castanet-Tolosan, France
- Centre National de la Recherche Scientifique, CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), Unité Mixte de Recherches UMR2594, F-31326 Castanet-Tolosan, France
| | - Fabrice Roux
- Institut National de la Recherche Agronomique, INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), Unité Mixte de Recherches UMR441, F-31326 Castanet-Tolosan, France
- Centre National de la Recherche Scientifique, CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), Unité Mixte de Recherches UMR2594, F-31326 Castanet-Tolosan, France
| | - Patrick Vincourt
- Institut National de la Recherche Agronomique, INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), Unité Mixte de Recherches UMR441, F-31326 Castanet-Tolosan, France
- Centre National de la Recherche Scientifique, CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), Unité Mixte de Recherches UMR2594, F-31326 Castanet-Tolosan, France
| | - Laurence Godiard
- Institut National de la Recherche Agronomique, INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), Unité Mixte de Recherches UMR441, F-31326 Castanet-Tolosan, France
- Centre National de la Recherche Scientifique, CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), Unité Mixte de Recherches UMR2594, F-31326 Castanet-Tolosan, France
- * E-mail:
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Viranyi F, Gulya TJ, Tourvieille DL. Recent Changes in the Pathogenic Variability of Plasmopara Halstedii (Sunflower Downy Mildew) Populations from Different Continents. ACTA ACUST UNITED AC 2015. [DOI: 10.1515/helia-2015-0009] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractThe obligate biotrophic Oomycete, Plasmopara halstedii, causal agent of sunflower downy mildew, is capable of producing new pathogenic races over time. Although changes in the P. halstedii race composition were reviewed for the first time in 2007, since then the pathogen has continued to change its virulence character dramatically. There was a need, therefore, to update information on pathogenic diversity of P. halstedii by making accounts of the temporal and spacial changes in the pathogen populations in North and South America and Europe. This paper, based on current publications and personal communications, attempts to present an accurate overview of races in Europe and Americas for the last 7 years.
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Affiliation(s)
| | - Thomas J. Gulya
- 2USDA-ARS Sunflower and Plant Biology Research Unit, Fargo, ND, USA
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Soltani Najafabadi M, Abedini R, Eskandari H, Mehrabi R. Monitoring Three Plasmopara halstedii Resistance Genes in Iranian Sunflower Inbred Lines. IRANIAN JOURNAL OF BIOTECHNOLOGY 2015; 13:45-50. [PMID: 28959290 PMCID: PMC5435005 DOI: 10.15171/ijb.1047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Revised: 03/29/2015] [Accepted: 04/26/2015] [Indexed: 06/07/2023]
Abstract
BACKGROUND Downy mildew caused by Plasmopara halstedii is a devastating disease in sunflower worldwide. Several dominant resistance genes designated as Pl have been identified and linked molecular markers have been demonstrated. However, no information on theresistance genes is available forIranian lines. OBJECTIVES The presence of three map-based molecular markers previously proved to be linked to different resistance genes were evaluated in sunflower inbred lines. MATERIALS AND METHODS Using PCR-based and CAPS molecular markers, 26 sunflower inbred lines with different responses to P. halstedii race 100 were used to detect the presence of three resistance loci including Pl1 , Pl6 and Pl13 within the lines. RESULTS Molecular marker linked to Pl13 was present in some of the sunflower lines but was not correlated with the phenotypic reaction of the lines to race 100. Despite the use of three markers linked to Pl6 , PCR failed to amplify any corresponding product. This data may suggest that none of the genotypes possessed Pl6 locus. Pl1 -linked cleaved amplified polymorphic sequences (CAPS) were present in several resistance lines and effectively differentiated susceptible and resistant sunflower lines. CONCLUSIONS Applicability of molecular markers in breeding programs revisited in disease management.
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Affiliation(s)
- Masood Soltani Najafabadi
- Corresponding author: Masood Soltani Najafabadi, Seed and Plant Improvement Institute (SPII), Karaj, Iran. Tel: +98-26336703771, Fax: +98-26336702051,
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Gascuel Q, Martinez Y, Boniface MC, Vear F, Pichon M, Godiard L. The sunflower downy mildew pathogen Plasmopara halstedii. MOLECULAR PLANT PATHOLOGY 2015; 16:109-22. [PMID: 25476405 PMCID: PMC6638465 DOI: 10.1111/mpp.12164] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
UNLABELLED Downy mildew of sunflower is caused by Plasmopara halstedii (Farlow) Berlese & de Toni. Plasmopara halstedii is an obligate biotrophic oomycete pathogen that attacks annual Helianthus species and cultivated sunflower, Helianthus annuus. Depending on the sunflower developmental stage at which infection occurs, the characteristic symptoms range from young seedling death, plant dwarfing, leaf bleaching and sporulation to the production of infertile flowers. Downy mildew attacks can have a great economic impact on sunflower crops, and several Pl resistance genes are present in cultivars to protect them against the disease. Nevertheless, some of these resistances have been overcome by the occurrence of novel isolates of the pathogen showing increased virulence. A better characterization of P. halstedii infection and dissemination mechanisms, and the identification of the molecular basis of the interaction with sunflower, is a prerequisite to efficiently fight this pathogen. This review summarizes what is currently known about P. halstedii, provides new insights into its infection cycle on resistant and susceptible sunflower lines using scanning electron and light microscopy imaging, and sheds light on the pathogenicity factors of P. halstedii obtained from recent molecular data. TAXONOMY Kingdom Stramenopila; Phylum Oomycota; Class Oomycetes; Order Peronosporales; Family Peronosporaceae; Genus Plasmopara; Species Plasmopara halstedii. DISEASE SYMPTOMS Sunflower seedling damping off, dwarfing of the plant, bleaching of leaves, starting from veins, and visible white sporulation, initially on the lower side of cotyledons and leaves. Plasmopara halstedii infection may severely impact sunflower seed yield. INFECTION PROCESS In spring, germination of overwintered sexual oospores leads to sunflower root infection. Intercellular hyphae are responsible for systemic plant colonization and the induction of disease symptoms. Under humid and fresh conditions, dissemination structures are produced by the pathogen on all plant organs to release asexual zoosporangia. These zoosporangia play an important role in pathogen dissemination, as they release motile zoospores that are responsible for leaf infections on neighbouring plants. DISEASE CONTROL Disease control is obtained by both chemical seed treatment (mefenoxam) and the deployment of dominant major resistance genes, denoted Pl. However, the pathogen has developed fungicide resistance and has overcome some plant resistance genes. Research for more sustainable strategies based on the identification of the molecular basis of the interaction are in progress. USEFUL WEBSITES http://www.heliagene.org/HP, http://lipm-helianthus.toulouse.inra.fr/dokuwiki/doku.php?id=start, https://www.heliagene.org/PlasmoparaSpecies (soon available).
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Affiliation(s)
- Quentin Gascuel
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, F-31326, Castanet-Tolosan, France; CNRS, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR2594, F-31326, Castanet-Tolosan, France
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Zerillo MM, Ibarra Caballero J, Woeste K, Graves AD, Hartel C, Pscheidt JW, Tonos J, Broders K, Cranshaw W, Seybold SJ, Tisserat N. Population structure of Geosmithia morbida, the causal agent of thousand cankers disease of walnut trees in the United States. PLoS One 2014; 9:e112847. [PMID: 25393300 PMCID: PMC4231075 DOI: 10.1371/journal.pone.0112847] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2014] [Accepted: 10/16/2014] [Indexed: 11/18/2022] Open
Abstract
The ascomycete Geosmithia morbida and the walnut twig beetle Pityophthorus juglandis are associated with thousand cankers disease of Juglans (walnut) and Pterocarya (wingnut). The disease was first reported in the western United States (USA) on several Juglans species, but has been found more recently in the eastern USA in the native range of the highly susceptible Juglans nigra. We performed a comprehensive population genetic study of 209 G. morbida isolates collected from Juglans and Pterocarya from 17 geographic regions distributed across 12 U.S. states. The study was based on sequence typing of 27 single nucleotide polymorphisms from three genomic regions and genotyping with ten microsatellite primer pairs. Using multilocus sequence-typing data, 197 G. morbida isolates were placed into one of 57 haplotypes. In some instances, multiple haplotypes were recovered from isolates collected on the same tree. Twenty-four of the haplotypes (42%) were recovered from more than one isolate; the two most frequently occurring haplotypes (H02 and H03) represented 36% of all isolates. These two haplotypes were abundant in California, but were not recovered from Arizona or New Mexico. G. morbida population structure was best explained by four genetically distinct groups that clustered into three geographic regions. Most of the haplotypes isolated from the native range of J. major (Arizona and New Mexico) were found in those states only or present in distinct genetic clusters. There was no evidence of sexual reproduction or genetic recombination in any population. The scattered distribution of the genetic clusters indicated that G. morbida was likely disseminated to different regions at several times and from several sources. The large number of haplotypes observed and the genetic complexity of G. morbida indicate that it evolved in association with at least one Juglans spp. and the walnut twig beetle long before the first reports of the disease.
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Affiliation(s)
- Marcelo M. Zerillo
- Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, Colorado, United States of America
- * E-mail:
| | - Jorge Ibarra Caballero
- Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, Colorado, United States of America
| | - Keith Woeste
- USDA Forest Service Hardwood Tree Improvement and Regeneration Center, Department of Forestry and Natural Resources, Purdue University, West Lafayette, Indiana, United States of America
| | - Andrew D. Graves
- USDA Forest Service, Forest Health Protection, Albuquerque, New Mexico, United States of America
| | - Colleen Hartel
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, Indiana, United States of America
| | - Jay W. Pscheidt
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America
| | - Jadelys Tonos
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, Indiana, United States of America
| | - Kirk Broders
- Department of Biological Sciences, University of New Hampshire, Durham, New Hampshire, United States of America
| | - Whitney Cranshaw
- Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, Colorado, United States of America
| | - Steven J. Seybold
- USDA Forest Service, Pacific Southwest Research Station, Davis, California, United States of America
| | - Ned Tisserat
- Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, Colorado, United States of America
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Fontaine MC, Gladieux P, Hood ME, Giraud T. History of the invasion of the anther smut pathogen on Silene latifolia in North America. THE NEW PHYTOLOGIST 2013; 198:946-956. [PMID: 23406496 DOI: 10.1111/nph.12177] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 01/09/2013] [Indexed: 06/01/2023]
Abstract
Understanding the routes of pathogen introduction contributes greatly to efforts to protect against future disease emergence. Here, we investigated the history of the invasion in North America by the fungal pathogen Microbotryum lychnidis-dioicae, which causes the anther smut disease on the white campion Silene latifolia. This system is a well-studied model in evolutionary biology and ecology of infectious disease in natural systems. Analyses based on microsatellite markers show that the introduced American M. lychnidis-dioicae probably came from Scotland, from a single population, and thus suffered from a drastic bottleneck compared with genetic diversity in the native European range. The pattern in M. lychnidis-dioicae contrasts with that found by previous studies in its host plant species S. latifolia, also introduced in North America. In the plant, several European lineages have been introduced from across Europe. The smaller number of introductions for M. lychnidis-dioicae probably relates to its life history traits, as it is an obligate, specialized pathogen that is neither transmitted by the seeds nor persistent in the environment. The results show that even a nonagricultural, biotrophic, and insect-vectored pathogen suffering from a very strong bottleneck can successfully establish populations on its introduced host.
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Affiliation(s)
- Michael C Fontaine
- Université Paris-Sud, Laboratoire Ecologie, Systématique et Evolution, UMR8079, Orsay Cedex, F-91405, France
- CNRS, UMR 8079, Orsay Cedex, F-91405, France
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Pierre Gladieux
- Université Paris-Sud, Laboratoire Ecologie, Systématique et Evolution, UMR8079, Orsay Cedex, F-91405, France
- CNRS, UMR 8079, Orsay Cedex, F-91405, France
- Plant and Microbial Biology, University of California, Berkeley, CA, USA
| | - Michael E Hood
- Department of Biology, Amherst College, Amherst, MA, USA
| | - Tatiana Giraud
- Université Paris-Sud, Laboratoire Ecologie, Systématique et Evolution, UMR8079, Orsay Cedex, F-91405, France
- CNRS, UMR 8079, Orsay Cedex, F-91405, France
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Fontaine MC, Austerlitz F, Giraud T, Labbé F, Papura D, Richard-Cervera S, Delmotte F. Genetic signature of a range expansion and leap-frog event after the recent invasion of Europe by the grapevine downy mildew pathogenPlasmopara viticola. Mol Ecol 2013; 22:2771-86. [DOI: 10.1111/mec.12293] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 02/11/2013] [Accepted: 02/14/2013] [Indexed: 01/26/2023]
Affiliation(s)
- Michael C. Fontaine
- Ecologie, Systématique et Evolution; UMR 8079 Université Paris Sud Laboratoire Ecologie; Systematique et Evolution; UMR8079 Orsay Cedex F-91405 France
- Eco-Anthropologie et Ethnobiologie; UMR 7206 CNRS; MNHN; Univ Paris Diderot; Sorbonne Paris Cité F-75231 Paris Cedex 5 France
| | - Fréderic Austerlitz
- Ecologie, Systématique et Evolution; UMR 8079 Université Paris Sud Laboratoire Ecologie; Systematique et Evolution; UMR8079 Orsay Cedex F-91405 France
- Eco-Anthropologie et Ethnobiologie; UMR 7206 CNRS; MNHN; Univ Paris Diderot; Sorbonne Paris Cité F-75231 Paris Cedex 5 France
| | - Tatiana Giraud
- Ecologie, Systématique et Evolution; UMR 8079 Université Paris Sud Laboratoire Ecologie; Systematique et Evolution; UMR8079 Orsay Cedex F-91405 France
| | - Frédéric Labbé
- Ecologie, Systématique et Evolution; UMR 8079 Université Paris Sud Laboratoire Ecologie; Systematique et Evolution; UMR8079 Orsay Cedex F-91405 France
| | - Daciana Papura
- INRA; UMR1065 Santé et Agroécologie du Vignoble; ISVV; F-33883 Villenave d'Ornon Cedex France
| | - Sylvie Richard-Cervera
- INRA; UMR1065 Santé et Agroécologie du Vignoble; ISVV; F-33883 Villenave d'Ornon Cedex France
| | - François Delmotte
- INRA; UMR1065 Santé et Agroécologie du Vignoble; ISVV; F-33883 Villenave d'Ornon Cedex France
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Aguayo J, Adams GC, Halkett F, Catal M, Husson C, Nagy ZÁ, Hansen EM, Marçais B, Frey P. Strong genetic differentiation between North American and European populations of Phytophthora alni subsp. uniformis. PHYTOPATHOLOGY 2013; 103:190-199. [PMID: 23095465 DOI: 10.1094/phyto-05-12-0116-r] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Alder decline caused by Phytophthora alni has been one of the most important diseases of natural ecosystems in Europe during the last 20 years. The emergence of P. alni subsp. alni -the pathogen responsible for the epidemic-is linked to an interspecific hybridization event between two parental species: P. alni subsp. multiformis and P. alni subsp. uniformis. One of the parental species, P. alni subsp. uniformis, has been isolated in several European countries and, recently, in North America. The objective of this work was to assess the level of genetic diversity, the population genetic structure, and the putative reproduction mode and mating system of P. alni subsp. uniformis. Five new polymorphic microsatellite markers were used to contrast both geographical populations. The study comprised 71 isolates of P. alni subsp. uniformis collected from eight European countries and 10 locations in North America. Our results revealed strong differences between continental populations (Fst = 0.88; Rst = 0.74), with no evidence for gene flow. European isolates showed extremely low genetic diversity compared with the North American collection. Selfing appears to be the predominant mating system in both continental collections. The results suggest that the European P. alni subsp. uniformis population is most likely alien and derives from the introduction of a few individuals, whereas the North American population probably is an indigenous population.
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Affiliation(s)
- Jaime Aguayo
- INRA, UMR1136, INRA, Université de Lorraine, Interactions Arbres- Micro- organismes, IFR110 EFABA, Centre INRA de Nancy, 54280 Champenoux, France
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15
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Sakr N. Diversity in Plasmopara halstedii,the Causal Agent of Sunflower Downy Mildew. CRYPTOGAMIE MYCOL 2012. [DOI: 10.7872/crym.v33.iss4.2012.463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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16
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Ahmed S, de Labrouhe DT, Delmotte F. Emerging virulence arising from hybridisation facilitated by multiple introductions of the sunflower downy mildew pathogen Plasmopara halstedii. Fungal Genet Biol 2012; 49:847-55. [DOI: 10.1016/j.fgb.2012.06.012] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 06/20/2012] [Accepted: 06/22/2012] [Indexed: 11/24/2022]
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17
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Liu Z, Gulya TJ, Seiler GJ, Vick BA, Jan CC. Molecular mapping of the Pl(16) downy mildew resistance gene from HA-R4 to facilitate marker-assisted selection in sunflower. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2012; 125:121-31. [PMID: 22350177 DOI: 10.1007/s00122-012-1820-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 02/04/2012] [Indexed: 05/20/2023]
Abstract
The major genes controlling sunflower downy mildew resistance have been designated as Pl genes. Ten of the more than 20 Pl genes reported have been mapped. In this study, we report the molecular mapping of gene Pl(16) in a sunflower downy mildew differential line, HA-R4. It was mapped on the lower end of linkage group (LG) 1 of the sunflower reference map, with 12 markers covering a distance of 78.9 cM. One dominant simple sequence repeat (SSR) marker, ORS1008, co-segregated with Pl(16), and another co-dominant expressed sequence tag (EST)-SSR marker, HT636, was located 0.3 cM proximal to the Pl(16) gene. The HT636 marker was also closely linked to the Pl(13) gene in another sunflower differential line, HA-R5. Thus the Pl(16) and Pl(13) genes were mapped to a similar position on LG 1 that is different from the previously reported Pl(14) gene. When the co-segregating and tightly linked markers for the Pl(16) gene were applied to other germplasms or hybrids, a unique band pattern for the ORS1008 marker was detected in HA-R4 and HA-R5 and their F(1) hybrids. This is the first report to provide two tightly linked markers for both the Pl(16) and Pl(13) genes, which will facilitate marker-assisted selection in sunflower resistance breeding, and provide a basis for the cloning of these genes.
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Affiliation(s)
- Zhao Liu
- Department of plant sciences, North Dakota State University, Fargo, ND 58102, USA
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18
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Dutech C, Barrès B, Bridier J, Robin C, Milgroom MG, Ravigné V. The chestnut blight fungus world tour: successive introduction events from diverse origins in an invasive plant fungal pathogen. Mol Ecol 2012; 21:3931-46. [PMID: 22548317 DOI: 10.1111/j.1365-294x.2012.05575.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Clonal expansion has been observed in several invasive fungal plant pathogens colonizing new areas, raising the question of the origin of clonal lineages. Using microsatellite markers, we retraced the evolutionary history of introduction of the chestnut blight fungus, Cryphonectria parasitica, in North America and western Europe. Combining discriminant analysis of principal components and approximate Bayesian computation analysis, we showed that several introduction events from genetically differentiated source populations have occurred in both invaded areas. In addition, a low signal of genetic recombination among different source populations was suggested in North America. Finally, two genetic lineages were present in both invaded areas as well as in the native areas, suggesting the existence of genetic lineages with a high capacity to establish in diverse environments and host species. This study confirmed the importance of multiple introductions, but questioned the role of genetic admixture in the success of introduction of a fungal plant pathogen.
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Affiliation(s)
- C Dutech
- INRA, UMR1202 BIOGECO, Cestas F-33610, France.
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19
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As-sadi F, Carrere S, Gascuel Q, Hourlier T, Rengel D, Le Paslier MC, Bordat A, Boniface MC, Brunel D, Gouzy J, Godiard L, Vincourt P. Transcriptomic analysis of the interaction between Helianthus annuus and its obligate parasite Plasmopara halstedii shows single nucleotide polymorphisms in CRN sequences. BMC Genomics 2011; 12:498. [PMID: 21988821 PMCID: PMC3204308 DOI: 10.1186/1471-2164-12-498] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Accepted: 10/11/2011] [Indexed: 11/30/2022] Open
Abstract
Background Downy mildew in sunflowers (Helianthus annuus L.) is caused by the oomycete Plasmopara halstedii (Farl.) Berlese et de Toni. Despite efforts by the international community to breed mildew-resistant varieties, downy mildew remains a major threat to the sunflower crop. Very few genomic, genetic and molecular resources are currently available to study this pathogen. Using a 454 sequencing method, expressed sequence tags (EST) during the interaction between H. annuus and P. halstedii have been generated and a search was performed for sites in putative effectors to show polymorphisms between the different races of P. halstedii. Results A 454 pyrosequencing run of two infected sunflower samples (inbred lines XRQ and PSC8 infected with race 710 of P. halstedii, which exhibit incompatible and compatible interactions, respectively) generated 113,720 and 172,107 useable reads. From these reads, 44,948 contigs and singletons have been produced. A bioinformatic portal, HP, was specifically created for in-depth analysis of these clusters. Using in silico filtering, 405 clusters were defined as being specific to oomycetes, and 172 were defined as non-specific oomycete clusters. A subset of these two categories was checked using PCR amplification, and 86% of the tested clusters were validated. Twenty putative RXLR and CRN effectors were detected using PSI-BLAST. Using corresponding sequences from four races (100, 304, 703 and 710), 22 SNPs were detected, providing new information on pathogen polymorphisms. Conclusions This study identified a large number of genes that are expressed during H. annuus/P. halstedii compatible or incompatible interactions. It also reveals, for the first time, that an infection mechanism exists in P. halstedii similar to that in other oomycetes associated with the presence of putative RXLR and CRN effectors. SNPs discovered in CRN effector sequences were used to determine the genetic distances between the four races of P. halstedii. This work therefore provides valuable tools for further discoveries regarding the H. annuus/P. halstedii pathosystem.
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Affiliation(s)
- Falah As-sadi
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, F-31326 Castanet-Tolosan, France
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Characterization of single-nucleotide-polymorphism markers for Plasmopara viticola, the causal agent of grapevine downy mildew. Appl Environ Microbiol 2011; 77:7861-3. [PMID: 21926208 DOI: 10.1128/aem.05782-11] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We report 34 new nuclear single-nucleotide-polymorphism (SNP) markers that have been developed from an expressed sequence tag library of Plasmopara viticola, the causal agent of grapevine downy mildew. This newly developed battery of markers will provide useful additional genetic tools for population genetic studies of this important agronomic species.
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21
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Wieckhorst S, Bachlava E, Dußle CM, Tang S, Gao W, Saski C, Knapp SJ, Schön CC, Hahn V, Bauer E. Fine mapping of the sunflower resistance locus Pl(ARG) introduced from the wild species Helianthus argophyllus. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2010; 121:1633-44. [PMID: 20700574 PMCID: PMC2963734 DOI: 10.1007/s00122-010-1416-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Accepted: 07/08/2010] [Indexed: 05/04/2023]
Abstract
Downy mildew, caused by Plasmopara halstedii, is one of the most destructive diseases in cultivated sunflower (Helianthus annuus L.). The dominant resistance locus Pl(ARG) originates from silverleaf sunflower (H. argophyllus Torrey and Gray) and confers resistance to all known races of P. halstedii. We mapped Pl(ARG) on linkage group (LG) 1 of (cms)HA342 × ARG1575-2, a population consisting of 2,145 F(2) individuals. Further, we identified resistance gene candidates (RGCs) that cosegregated with Pl(ARG) as well as closely linked flanking markers. Markers from the target region were mapped with higher resolution in NDBLOS(sel) × KWS04, a population consisting of 2,780 F(2) individuals that does not segregate for Pl(ARG). A large-insert sunflower bacterial artificial chromosome (BAC) library was screened with overgo probes designed for markers RGC52 and RGC151, which cosegregated with Pl(ARG). Two RGC-containing BAC contigs were anchored to the Pl(ARG) region on LG 1.
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Affiliation(s)
- S. Wieckhorst
- Plant Breeding, Center of Life and Food Sciences Weihenstephan, Technische Universität München, 85354 Freising, Germany
| | - E. Bachlava
- Center for Applied Genetic Technologies, University of Georgia, Athens, GA 30602 USA
| | - C. M. Dußle
- State Plant Breeding Institute, Universität Hohenheim, 70599 Stuttgart, Germany
| | - S. Tang
- Center for Applied Genetic Technologies, University of Georgia, Athens, GA 30602 USA
| | - W. Gao
- Center for Applied Genetic Technologies, University of Georgia, Athens, GA 30602 USA
| | - C. Saski
- Clemson University Genomics Institute, Clemson, SC 29634 USA
| | - S. J. Knapp
- Center for Applied Genetic Technologies, University of Georgia, Athens, GA 30602 USA
- Present Address: Monsanto Vegetables, Inc., 37437 State Highway 16, Woodland, CA 95695 USA
| | - C.-C. Schön
- Plant Breeding, Center of Life and Food Sciences Weihenstephan, Technische Universität München, 85354 Freising, Germany
| | - V. Hahn
- State Plant Breeding Institute, Universität Hohenheim, 70599 Stuttgart, Germany
| | - E. Bauer
- Plant Breeding, Center of Life and Food Sciences Weihenstephan, Technische Universität München, 85354 Freising, Germany
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Inferring the evolutionary history of the plant pathogen Pseudomonas syringae from its biogeography in headwaters of rivers in North America, Europe, and New Zealand. mBio 2010; 1. [PMID: 20802828 PMCID: PMC2925074 DOI: 10.1128/mbio.00107-10] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Accepted: 06/02/2010] [Indexed: 11/26/2022] Open
Abstract
Nonhost environmental reservoirs of pathogens play key roles in their evolutionary ecology and in particular in the evolution of pathogenicity. In light of recent reports of the plant pathogen Pseudomonas syringae in pristine waters outside agricultural regions and its dissemination via the water cycle, we have examined the genetic and phenotypic diversity, population structure, and biogeography of P. syringae from headwaters of rivers on three continents and their phylogenetic relationship to strains from crops. A collection of 236 strains from 11 sites in the United States, in France, and in New Zealand was characterized for genetic diversity based on housekeeping gene sequences and for phenotypic diversity based on measures of pathogenicity and ice nucleation activity. Phylogenetic analyses revealed several new genetic clades from water. The genetic structure of P. syringae populations was not influenced by geographic location or water chemistry, whereas the phenotypic structure was affected by these parameters. Comparison with strains from crops revealed that the metapopulation of P. syringae is structured into three genetic ecotypes: a crop-specific type, a water-specific type, and an abundant ecotype found in both habitats. Aggressiveness of strains was significantly and positively correlated with ice nucleation activity. Furthermore, the ubiquitous genotypes were the most aggressive, on average. The abundance and diversity in water relative to crops suggest that adaptation to the freshwater habitat has played a nonnegligible role in the evolutionary history of P. syringae. We discuss how adaptation to the water cycle is linked to the epidemiological success of this plant pathogen. Many pathogens have life cycles that involve survival and multiplication in nonhost environmental habitats. For human pathogens, numerous studies have revealed how adaptation to environmental habitats is linked to the evolution of their pathogenicity and emergence of pathogens. For plant pathogens, the link between adaptation to nonhost habitats and pathogenicity has not been explored. Here we have examined the genetic and phenotypic diversity of the plant pathogen Pseudomonas syringae in headwaters of rivers on three continents and compared it to that of strains from crops. This model pathogen was chosen because it is widely abundant in habitats associated with the water cycle and in particular in pristine waters outside agricultural regions. This work reveals that there is considerable exchange of populations between freshwater and agricultural habitats and that those in the former contribute considerably to the diversification of P. syringae.
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Montarry J, Andrivon D, Glais I, Corbiere R, Mialdea G, Delmotte F. Microsatellite markers reveal two admixed genetic groups and an ongoing displacement within the French population of the invasive plant pathogen Phytophthora infestans. Mol Ecol 2010; 19:1965-77. [PMID: 20345671 DOI: 10.1111/j.1365-294x.2010.04619.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Potato late blight is an example of a re-emerging disease of plants. Phytophthora infestans was first introduced into Europe during the 19th century, where it caused the Irish potato famine. During the 20th century several additional introduction events have been suspected, especially in the mid-70s due to the import of large quantities of potato needed after the shortage caused by drought in 1976. Here, we investigate the genetic population structure of Phytophthora infestans, at the first stages of a recent invasion process in France. A total of 220 isolates was collected from 20 commercial fields of the potato susceptible cultivar Bintje, during two consecutive years (2004 and 2005). Clustering analyses based on eight recently developed microsatellite markers reveal that French P. infestans populations are made of two differentiated genetic clusters of isolates (F(ST) = 0.19). This result suggests multiple introductions of P. infestans into France, either through the introduction of a composite population of isolates or through the successive introduction of isolates having differentiated genetic backgrounds. Both clusters identified have a strong clonal structure and are similar regarding genetic diversity and mating type composition. The maintenance of differentiation between the two genetic clusters should result from the low or non-existent contribution of sexual reproduction in French P. infestans populations.
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Dutech C, Fabreguettes O, Capdevielle X, Robin C. Multiple introductions of divergent genetic lineages in an invasive fungal pathogen, Cryphonectria parasitica, in France. Heredity (Edinb) 2009; 105:220-8. [PMID: 19997121 DOI: 10.1038/hdy.2009.164] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The occurrence of multiple introductions may be a crucial factor in the successful establishment of invasive species, but few studies focus on the introduction of fungal pathogens, despite their significant effect on invaded habitats. Although Cryphonectria parasitica, the chestnut blight fungus introduced in North America and Europe from Asia during the 20th century, caused dramatic changes in its new range, the history of its introduction is not well retraced in Europe. Using 10 microsatellite loci, we investigated the genetic diversity of 583 isolates in France, where several introductions have been hypothesized. Our analyses showed that the seven most frequent multilocus genotypes belonged to three genetic lineages, which had a different and geographically limited distribution. These results suggest that different introduction events occurred in France. Genetic recombination was low among these lineages, despite the presence of the two mating types in each chestnut stand analysed. The spatial distribution of lineages suggests that the history of introductions in France associated with the slow expansion of the disease has contributed to the low observed rate of recombination among the divergent lineages. However, we discuss the possibility that environmental conditions or viral interactions could locally reduce recombination among genotypes.
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Affiliation(s)
- C Dutech
- INRA, UMR 1202 BIOGECO, Equipe de Pathologie Forestière, Domaine de Pierroton, Cestas, France.
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25
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Mulpuri S, Liu Z, Feng J, Gulya TJ, Jan CC. Inheritance and molecular mapping of a downy mildew resistance gene, Pl (13) in cultivated sunflower (Helianthus annuus L.). TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2009; 119:795-803. [PMID: 19557383 DOI: 10.1007/s00122-009-1089-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2008] [Accepted: 05/30/2009] [Indexed: 05/20/2023]
Abstract
The inheritance of resistance to sunflower downy mildew (SDM) derived from HA-R5 conferring resistance to nine races of the pathogen has been determined and the new source has been designated as Pl ( 13 ) . The F(2) individuals and F(3) families of the cross HA-R5 (resistant) x HA 821 (susceptible) were screened against the four predominant SDM races 300, 700, 730, and 770 in separate tests which indicated dominant control by a single locus or a cluster of tightly linked genes. Bulked segregant analysis (BSA) was carried out on 116 F(2) individuals with 500 SSR primer pairs that resulted in the identification of 10 SSR markers of linkage groups 1 (9 markers) and 10 (1 marker) of the genetic map (Tang et al. in Theor Appl Genet 105:1124-1136, 2002) that distinguished the bulks. Of these, the SSR marker ORS 1008 of linkage group 10 was tightly linked (0.9 cM) to the Pl (13) gene. Genotyping the F(2) population and linkage analysis with 20 polymorphic primer pairs located on linkage group 10 failed to show linkage of the markers with downy mildew resistance and the ORS 1008 marker. Nevertheless, validation of polymorphic SSR markers of linkage group 1 along with six RFLP-based STS markers of linkage group 12 of the RFLP map of Jan et al. (Theor Appl Genet 96:15-22, 1998) corresponding to linkage group 1 of the SSR map, mapped seven SSR markers (ORS 965-1, ORS 965-2, ORS 959, ORS 371, ORS 716, and ORS 605) including ORS 1008 and one STS marker (STS10D6) to linkage group 1 covering a genetic distance of 65.0 cM. The Pl (13) gene, as a different source with its location on linkage group 1, was flanked by ORS 1008 on one side at a distance of 0.9 cM and ORS 965-1 on another side at a distance of 5.8 cM. These closely linked markers to the Pl (13) gene provide a valuable basis for marker-assisted selection in sunflower breeding programs.
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Affiliation(s)
- Sujatha Mulpuri
- Directorate of Oilseeds Research, Rajendranagar, Hyderabad 500030, India
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