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Mariotti L, Fambrini M, Scartazza A, Picciarelli P, Pugliesi C. Characterization of lingering hope, a new brachytic mutant in sunflower (Helianthus annuus L.) with altered salicylic acid metabolism. JOURNAL OF PLANT PHYSIOLOGY 2018; 231:402-414. [PMID: 30399536 DOI: 10.1016/j.jplph.2018.10.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 10/02/2018] [Accepted: 10/22/2018] [Indexed: 06/08/2023]
Abstract
Dwarf mutants are useful to elucidate regulatory mechanisms of plant growth and development. A brachytic mutant, named lingering hope (linho), was recently isolated from sunflower (Helianthus annuus). The aim of this report is the characterization of the mutant through genetic, morphometric, physiological and gene expression analyses. The brachytic trait is controlled by a recessive gene. The reduction of plant height depends on shorter apical internodes. The mutant shows an altered ratio length/width of the leaf blade, chlorosis and defects in inflorescence development. The brachytic trait is not associated to a specific hormonal deficiency, but an increased level of several gibberellins is detected in leaves. Notably, the endogenous salicylic acid (SA) content in young leaves of the mutant is very high despite a low level of SA 2-O-β-d-glucoside (SAG). The CO2 assimilation rate significantly decreases in the second pair of leaves of linho, due to effects of both stomatal and non-stomatal constraints. In addition, the reduction of both actual and potential photochemical efficiency of photosystem II is associated with a reduced content of chlorophylls and carotenoids, a lower chlorophyll a to chlorophyll b ratio and a higher SA content. In comparison to wild type, linho shows a different pattern of gene expression with respect two pathogenesis-related genes and two genes involved in SA biosynthesis and SA metabolism. linho is the first mutant described in sunflower with altered SA metabolism and this genotype could be useful to improve information about the effects of high endogenous content of SA on plant development, reproductive growth and photosynthesis, in a major crop.
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Affiliation(s)
- Lorenzo Mariotti
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, I-56124 Pisa, Italy
| | - Marco Fambrini
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, I-56124 Pisa, Italy
| | - Andrea Scartazza
- Institute of Research on Terrestrial Ecosystems (IRET), National Research Council of Italy (CNR),Via Salaria Km 29,300, I-00015 Monterotondo Scalo, RM, Italy
| | - Piero Picciarelli
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, I-56124 Pisa, Italy
| | - Claudio Pugliesi
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, I-56124 Pisa, Italy.
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Şahin EÇ, Kalenderoğlu A, Aydın Y, Evci G, Uncuoğlu AA. SSR Markers Suitable for Marker Assisted Selection in Sunflower for Downy Mildew Resistance. Open Life Sci 2018; 13:319-326. [PMID: 33817099 PMCID: PMC7874726 DOI: 10.1515/biol-2018-0039] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Accepted: 06/10/2018] [Indexed: 11/15/2022] Open
Abstract
The effectiveness of Pl genes is known to be resistant to downy mildew (DM) disease affected by fungus Plasmopara halstedii in sunflower. In this study phenotypic analysis was performed using inoculation tests and genotypic analysis were carried out with three DM resistance genes Plarg, Pl13 and Pl8. A total of 69 simple sequence repeat markers and 241 F2 individuals derived from a cross of RHA-419 (R) x P6LC (S), RHA-419 (R) x CL (S), RHA-419 (R) x OL (S), RHA419 (R) x 9758R (S), HA-R5 (R) x P6LC (S) and HA89 (R) x P6LC (S) parental lines were used to identify resistant hybrids in sunflower. Results of SSR analysis using markers linked with downy mildew resistance genes (Plarg, Pl8 and Pl13) and downy mildew inoculation tests were evaluated together and ORS716 (for Plarg and Pl13), HA4011 (for Pl8) markers showed positive correlation with their phenotypic results. These results suggest that these markers are associated with DM resistance and they can be used successfully in marker-assisted selection for sunflower breeding programs specific for downy mildew resistance.
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Affiliation(s)
- Ezgi Çabuk Şahin
- Department of Biology, Faculty of Science and Letters, Marmara University, Istanbul, 34722, Turkey
| | - Aral Kalenderoğlu
- Department of Bioengineering, Faculty of Engineering, Marmara University, Istanbul, 34722, Turkey
| | - Yıldız Aydın
- Department of Biology, Faculty of Science and Letters, Marmara University, Istanbul, 34722, Turkey
| | - Göksel Evci
- Republic of Turkey Ministry of Food, Agriculture and Livestock Directorate of Trakya Agricultural, Research Institute, Edirne, 22100, Turkey
| | - Ahu Altınkut Uncuoğlu
- Department of Bioengineering, Faculty of Engineering, Marmara University, Istanbul, 34722, Turkey
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Şestacova T, Giscă I, Cucereavîi A, Port A, Duca M. Expression of defence-related genes in sunflower infected with broomrape. BIOTECHNOL BIOTEC EQ 2016. [DOI: 10.1080/13102818.2016.1179591] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Affiliation(s)
- Tatiana Şestacova
- Laboratory of Genomics, University Center of Molecular Biology, University of the Academy of Sciences of Moldova, Chisinau, Republic of Moldova
| | - Ion Giscă
- Research Department, AMG-Agroselect Comerţ Company, Soroca, Republic of Moldova
| | - Aliona Cucereavîi
- Research Department, AMG-Agroselect Comerţ Company, Soroca, Republic of Moldova
| | - Angela Port
- Laboratory of Genomics, University Center of Molecular Biology, University of the Academy of Sciences of Moldova, Chisinau, Republic of Moldova
| | - Maria Duca
- Laboratory of Genomics, University Center of Molecular Biology, University of the Academy of Sciences of Moldova, Chisinau, Republic of Moldova
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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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Corti Monzón G, Pinedo M, Di Rienzo J, Novo-Uzal E, Pomar F, Lamattina L, de la Canal L. Nitric oxide is required for determining root architecture and lignin composition in sunflower. Supporting evidence from microarray analyses. Nitric Oxide 2014; 39:20-8. [PMID: 24747108 DOI: 10.1016/j.niox.2014.04.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 04/01/2014] [Accepted: 04/07/2014] [Indexed: 01/09/2023]
Abstract
Nitric oxide (NO) is a signal molecule involved in several physiological processes in plants, including root development. Despite the importance of NO as a root growth regulator, the knowledge about the genes and metabolic pathways modulated by NO in this process is still limited. A constraint to unravel these pathways has been the use of exogenous applications of NO donors that may produce toxic effects. We have analyzed the role of NO in root architecture through the depletion of endogenous NO using the scavenger cPTIO. Sunflower seedlings growing in liquid medium supplemented with cPTIO showed unaltered primary root length while the number of lateral roots was deeply reduced; indicating that endogenous NO participates in determining root branching in sunflower. The transcriptional changes induced by NO depletion have been analyzed using a large-scale approach. A microarray analysis showed 330 genes regulated in the roots (p≤0.001) upon endogenous NO depletion. A general cPTIO-induced up-regulation of genes involved in the lignin biosynthetic pathway was observed. Even if no detectable changes in total lignin content could be detected, cell walls analyses revealed that the ratio G/S lignin increased in roots treated with cPTIO. This means that endogenous NO may control lignin composition in planta. Our results suggest that a fine tuning regulation of NO levels could be used by plants to regulate root architecture and lignin composition. The functional implications of these findings are discussed.
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Affiliation(s)
- Georgina Corti Monzón
- Instituto de Investigaciones Biológicas, Universidad Nacional de Mar del Plata-CONICET, Mar del Plata, Argentina.
| | - Marcela Pinedo
- Instituto de Investigaciones Biológicas, Universidad Nacional de Mar del Plata-CONICET, Mar del Plata, Argentina.
| | - Julio Di Rienzo
- Cátedra de Estadística y Biometría, Facultad de Ciencias Agropecuarias, Universidad Nacional de Córdoba, Córdoba, Argentina.
| | - Esther Novo-Uzal
- Departamento de Biología Vegetal, Universidad de Murcia, Murcia, Spain.
| | - Federico Pomar
- Departamento de Biología Animal, Biología Vegetal y Ecología, Universidade da Coruña, A Coruña, Spain.
| | - Lorenzo Lamattina
- Instituto de Investigaciones Biológicas, Universidad Nacional de Mar del Plata-CONICET, Mar del Plata, Argentina.
| | - Laura de la Canal
- Instituto de Investigaciones Biológicas, Universidad Nacional de Mar del Plata-CONICET, Mar del Plata, Argentina.
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Franchel J, Bouzidi MF, Bronner G, Vear F, Nicolas P, Mouzeyar S. Positional cloning of a candidate gene for resistance to the sunflower downy mildew, Plasmopara halstedii race 300. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2013; 126:359-367. [PMID: 23052021 DOI: 10.1007/s00122-012-1984-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 09/15/2012] [Indexed: 06/01/2023]
Abstract
The resistance of sunflower to Plasmopara halstedii is conferred by major resistance genes denoted Pl. Previous genetic studies indicated that the majority of these genes are clustered on linkage groups 8 and 13. The Pl6 locus is one of the main clusters to have been identified, and confers resistance to several P. halstedii races. In this study, a map-based cloning strategy was implemented using a large segregating F2 population to establish a fine physical map of this cluster. A marker derived from a bacterial artificial chromosome (BAC) clone was found to be very tightly linked to the gene conferring resistance to race 300, and the corresponding BAC clone was sequenced and annotated. It contains several putative genes including three toll-interleukin receptor-nucleotide binding site-leucine rich repeats (TIR-NBS-LRR) genes. However, only one TIR-NBS-LRR appeared to be expressed, and thus constitutes a candidate gene for resistance to P. halstedii race 300.
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Affiliation(s)
- Jérôme Franchel
- Clermont Université, Université Blaise Pascal, UMR INRA-UBP 1095 GDEC, BP 10448, 63000 Clermont-Ferrand, France
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Radwan O, Bouzidi MF, Mouzeyar S. Molecular characterization of two types of resistance in sunflower to Plasmopara halstedii, the causal agent of downy mildew. PHYTOPATHOLOGY 2011; 101:970-9. [PMID: 21751877 DOI: 10.1094/phyto-06-10-0163] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Depending on host-pathotype combination, two types of sunflower-Plasmopara halstedii incompatibility reactions have previously been identified. Type I resistance can restrict the growth of the pathogen in the basal region of the hypocotyls, whereas type II cannot, thus allowing the pathogen to reach the cotyledons. In type II resistance, a large portion of the hypocotyls is invaded by the pathogen and, subsequently, a hypersensitive reaction (HR) is activated over a long portion of the hypocotyls. Thus, the HR in type II resistance coincides with a higher induction of hsr203j sunflower homologue in comparison with type I resistance, where the HR is activated only in the basal part of hypocotyls. Although the pathogen was not detected in cotyledons of type I resistant plants, semiquantitative polymerase chain reaction confirmed the early abundant growth of the pathogen in cotyledons of susceptible plants by 6 days postinfection (dpi). This was in contrast to scarce growth of the pathogen in cotyledons of type II-resistant plants at a later time point (12 dpi). This suggests that pathogen growth differs according to the host-pathogen combination. To get more information about sunflower downy mildew resistance genes, the full-length cDNAs of RGC151 and RGC203, which segregated with the PlARG gene (resistance type I) and Pl14 gene (resistance type II), were cloned and sequenced. Sequence analyses revealed that RGC151 belongs to the Toll/interleukin-1 receptor (TIR) nucleotide-binding site leucine-rich repeat (NBS-LRR) class whereas RGC203 belongs to class coiled-coil (CC)-NBS-LRR. This study suggests that type II resistance may be controlled by CC-NBS-LRR gene transcripts which are enhanced upon infection by P. halstedii, rather than by the TIR-NBS-LRR genes that might control type I resistance.
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Affiliation(s)
- Osman Radwan
- National Soybean Research Center, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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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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Spring O. Transition of secondary to systemic infection of sunflower with Plasmopara halstedii – An underestimated factor in the epidemiology of the pathogen. FUNGAL ECOL 2009. [DOI: 10.1016/j.funeco.2008.12.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Chaki M, Fernandez-Ocana AM, Valderrama R, Carreras A, Esteban FJ, Luque F, Gomez-Rodriguez MV, Begara-Morales JC, Corpas FJ, Barroso JB. Involvement of reactive nitrogen and oxygen species (RNS and ROS) in sunflower-mildew interaction. Plant Cell Physiol. 50(2): 265-79 (2009). PLANT & CELL PHYSIOLOGY 2009; 50:665-79. [PMID: 19297722 DOI: 10.1093/pcp/pcp039] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
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Chaki M, Fernández-Ocaña AM, Valderrama R, Carreras A, Esteban FJ, Luque F, Gómez-Rodríguez MV, Begara-Morales JC, Corpas FJ, Barroso JB. Involvement of Reactive Nitrogen and Oxygen Species (RNS and ROS) in Sunflower–Mildew Interaction. ACTA ACUST UNITED AC 2008; 50:265-79. [DOI: 10.1093/pcp/pcn196] [Citation(s) in RCA: 141] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Zhang S, Zaitlin D. Genetic resistance to Peronospora tabacina in Nicotiana langsdorffii, a South American wild tobacco. PHYTOPATHOLOGY 2008; 98:519-28. [PMID: 18943219 DOI: 10.1094/phyto-98-5-0519] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Several accessions of Nicotiana langsdorffii, a wild tobacco relative native to South America, express an incompatible interaction in response to infection by Peronospora tabacina, an oömycete that causes blue mold disease of tobacco (N. tabacum) and many other species of Nicotiana. In resistant accessions of N. langsdorffii, such as S-4-4, incompatibility takes the form of necrotic lesions that appear 48 h after pathogen inoculation, restricting pathogen growth, and suppressing subsequent asexual sporulation. Significantly elevated levels of salicylic acid and expression of a defense-related gene (HSR203J) were observed in S-4-4 leaves following blue mold infection. Genetic segregation analysis in F(2) and modified backcross populations showed that blue mold resistance is determined by a single dominant gene (NlRPT) present in S-4-4. Further characterization of this unique host-pathogen interaction has revealed that (i) necrotic lesion resistance is due to the hypersensitive response (HR), (ii) HR-mediated resistance is present in 7 of 10 N. langsdorffii accessions examined, but not in closely related species, (iii) in some accessions of N. langsdorffii, resistance is expressed in cotyledon tissue and seedling leaves as well as in adult plants, and (iv) several resistant accessions including S-4-4 express an unregulated ("runaway") HR in response to P. tabacina infection.
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Affiliation(s)
- S Zhang
- Kentucky Tobacco Research and Development Center, Cooper and University Drives, University of Kentucky, Lexington 40546-0236, USA
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Bouzidi MF, Parlange F, Nicolas P, Mouzeyar S. Expressed Sequence Tags from the oomycete Plasmopara halstedii, an obligate parasite of the sunflower. BMC Microbiol 2007; 7:110. [PMID: 18062809 PMCID: PMC2242796 DOI: 10.1186/1471-2180-7-110] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2006] [Accepted: 12/06/2007] [Indexed: 11/24/2022] Open
Abstract
Background Sunflower downy mildew is a major disease caused by the obligatory biotrophic oomycete Plasmopara halstedii. Little is known about the molecular mechanisms underlying its pathogenicity. In this study we used a genomics approach to gain a first insight into the transcriptome of P. halstedii. Results To identify genes from the obligatory biotrophic oomycete Plasmopara halstedii that are expressed during infection in sunflower (Helianthus annuus L.) we employed the suppression subtraction hybridization (SSH) method from sunflower seedlings infected by P. halstedii. Using this method and random sequencing of clones, a total of 602 expressed sequence tags (ESTs) corresponding to 230 unique sequence sets were identified. To determine the origin of the unisequences, PCR primers were designed to amplify these gene fragments from genomic DNA isolated either from P. halstedii sporangia or from Helianthus annuus. Only 145 nonredundant ESTs which correspond to a total of 373 ESTs (67.7%) proved to be derived from P. halstedii genes and that are expressed during infection in sunflower. A set of 87 nonredundant sequences were identified as showing matches to sequences deposited in public databases. Nevertheless, about 7% of the ESTs seem to be unique to P. halstedii without any homolog in any public database. Conclusion A summary of the assignment of nonredundant ESTs to functional categories as well as their relative abundance is listed and discussed. Annotation of the ESTs revealed a number of genes that could function in virulence. We provide a first glimpse into the gene content of P. halstedii. These resources should accelerate research on this important pathogen.
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Affiliation(s)
- Mohamed Fouad Bouzidi
- UMR 1095 INRA-UBP "Amélioration et Santé des Plantes", Université Blaise Pascal, 24, Avenue des Landais 63177 Aubière Cedex, France.
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