Rhynchosporium

14,000,000 Leading Edge Experts on the ideXlab platform

Scan Science and Technology

Contact Leading Edge Experts & Companies

Scan Science and Technology

Contact Leading Edge Experts & Companies

The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Bruce A. Mcdonald - One of the best experts on this subject based on the ideXlab platform.

  • redefining genera of cereal pathogens oculimacula Rhynchosporium and spermospora
    Fungal systematics and evolution, 2021
    Co-Authors: P W Crous, Bruce A. Mcdonald, Celeste C. Linde, Paul S. Dyer, Uwe Braun, C L Lennox, Jacqueline Edwards, Ross Mann, Anjali Pranjivan Zaveri, J Z Groenewald
    Abstract:

    The taxonomy of Oculimacula, Rhynchosporium and Spermospora is re-evaluated, along with that of phylogenetically related genera. Isolates are identified using comparisons of DNA sequences of the internal transcribed spacer ribosomal RNA locus (ITS), partial translation elongation factor 1-alpha (tef1), actin (act), DNA-directed RNA polymerase II largest (rpb1) and second largest subunit (rpb2) genes, and the nuclear ribosomal large subunit (LSU), combined with their morphological characteristics. Oculimacula is restricted to two species, O. acuformis and O. yallundae, with O. aestiva placed in Cyphellophora, and O. anguioides accommodated in a new genus, Helgardiomyces. Rhynchosporium s. str. is restricted to species with 1-septate conidia and hooked apical beaks, while Rhynchobrunnera is introduced for species with 1-3-septate, straight conidia, lacking any apical beak. Rhynchosporium graminicola is proposed to replace the name R. commune applied to the barley scald pathogen based on nomenclatural priority. Spermospora is shown to be paraphyletic, representing Spermospora (type: S. subulata), with three new species, S. arrhenatheri, S. loliiphila and S. zeae, and Neospermospora gen. nov. (type: N. avenae). Ypsilina (type: Y. graminea), is shown to be monophyletic, but appears to be of minor importance on cereals. Finally, Vanderaaea gen. nov. (type: V. ammophilae), is introduced as a new coelomycetous fungus occurring on dead leaves of Ammophila arenaria. Citation: Crous PW, Braun U, McDonald BA, Lennox CL, Edwards J, Mann RC, Zaveri A, Linde CC, Dyer PS, Groenewald JZ (2020). Redefining genera of cereal pathogens: Oculimacula, Rhynchosporium and Spermospora. Fungal Systematics and Evolution7: 67-98. doi: 10.3114/fuse.2021.07.04.

  • comparative analysis of mitochondrial genomes from closely related Rhynchosporium species reveals extensive intron invasion
    Fungal Genetics and Biology, 2014
    Co-Authors: Stefano F F Torriani, Bruce A. Mcdonald, Wolfgang Knogge, Daniel Penselin, Marius Felder, Stefan Taudien, Matthias Platzer, Patrick C. Brunner
    Abstract:

    We sequenced and annotated the complete mitochondrial (mt) genomes of four closely related Rhynchosporium species that diverged ∼14,000-35,000years ago. During this time frame, three of the mt genomes expanded significantly due to an invasion of introns into three genes (cox1, cox2, and nad5). The enlarged mt genomes contained ∼40% introns compared to 8.1% in uninvaded relatives. Many intron gains were accompanied by co-conversion of flanking exonic regions. The comparative analysis revealed a highly variable set of non-intronic, free-standing ORFs of unknown function (uORFs). This is consistent with a rapidly evolving accessory compartment in the mt genome of these closely related species. Only one free-standing uORF was shared among all mt genomes analyzed. This uORF had a mutation rate similar to the core mt protein-encoding genes, suggesting conservation of function among the species. The nucleotide composition of the core protein-encoding genes significantly differed from those of introns and uORFs. The mt mutation rate was 77 times higher than the nuclear mutation rate, indicating that the phylogeny inferred from mt genes may better resolve the phylogenetic relationships among closely related Rhynchosporium species than phylogenies inferred from nuclear genes.

  • Phylogeographical analyses reveal global migration patterns Blackwell Publishing Ltd of the barley scald pathogen Rhynchosporium secalis
    2013
    Co-Authors: Pascal L. Zaffarano, Bruce A. Mcdonald, Celeste C. Linde
    Abstract:

    A phylogeographical analysis of the scald pathogen Rhynchosporium secalis was conducted using nuclear DNA sequences from two neutral restriction fragment length polymorphism loci and the mating-type idiomorphs. Approximately 500 isolates sampled from more than 60 field populations from five continents were analysed to infer migration patterns and the demographic history of the fungus. Migration rates among continents were generally low, consistent with earlier reports of significant population subdivision among continents. Northern Europe was mainly a source population for global migration. We hypothesize that the pathogen only recently moved out of its centre of origin, resulting in founder populations that are reproductively isolated due to the contemporary absence of long-distance gene flow

  • Electrophoretic karyotypes of Rhynchosporium commune, R. secalis and R. agropyri
    European Journal of Plant Pathology, 2011
    Co-Authors: Andreas Felten, Pascal L. Zaffarano, Bruce A. Mcdonald
    Abstract:

    Pulsed-field gel electrophoresis was used to generate electrophoretic karyotypes for 15 strains representing the three closely related plant-pathogenic fungi Rhynchosporium commune , R. secalis and R. agropyri . Between 13 and 16 chromosomes ranging in size from 0.9 to 6.4 Mb were found among the strains, leading to estimated genome sizes ranging from 54 to 63 Mb. Southern hybridization was used to identify homologous chromosomes, allowing detection of chromosome-length polymorphisms. There were no obvious differences in genome sizes or structures among the three species. The avirulence gene NIP1 is present on a large chromosome that is not likely to be dispensable. Two strains of R. commune that were proposed in earlier studies to be aneuploid as a result of a parasexual cycle did not possess a larger number of chromosomes. The reported information on genome size and chromosome number will be useful for genome sequencing projects that aim to identify genes involved in speciation and host specialization.

  • invasion of Rhynchosporium commune onto wild barley in the middle east
    Biological Invasions, 2011
    Co-Authors: A Kirosmeles, Bruce A. Mcdonald, Amor Yahyaoui, Don R Gomez, Celeste C. Linde
    Abstract:

    Rhynchosporium commune was recently introduced into the Middle East, presumably with the cultivated host barley (Hordeum vulgare). Middle Eastern populations of R. commune on cultivated barley and wild barley (H. spontaneum) were genetically undifferentiated and shared a high proportion of multilocus haplotypes. This suggests that there has been little selection for host specialization on H. spontaneum, a host population often used as a source of resistance genes introduced into its domesticated counterpart, H. vulgare. Low levels of pathogen genetic diversity on H. vulgare as well as on H. spontaneum, indicate that the pathogen was introduced recently into the Middle East, perhaps through immigration on infected cultivated barley seeds, and then invaded the wild barley population. Although it has not been documented, the introduction of the pathogen into the Middle East may have a negative influence on the biodiversity of native Hordeum species.

Celeste C. Linde - One of the best experts on this subject based on the ideXlab platform.

  • redefining genera of cereal pathogens oculimacula Rhynchosporium and spermospora
    Fungal systematics and evolution, 2021
    Co-Authors: P W Crous, Bruce A. Mcdonald, Celeste C. Linde, Paul S. Dyer, Uwe Braun, C L Lennox, Jacqueline Edwards, Ross Mann, Anjali Pranjivan Zaveri, J Z Groenewald
    Abstract:

    The taxonomy of Oculimacula, Rhynchosporium and Spermospora is re-evaluated, along with that of phylogenetically related genera. Isolates are identified using comparisons of DNA sequences of the internal transcribed spacer ribosomal RNA locus (ITS), partial translation elongation factor 1-alpha (tef1), actin (act), DNA-directed RNA polymerase II largest (rpb1) and second largest subunit (rpb2) genes, and the nuclear ribosomal large subunit (LSU), combined with their morphological characteristics. Oculimacula is restricted to two species, O. acuformis and O. yallundae, with O. aestiva placed in Cyphellophora, and O. anguioides accommodated in a new genus, Helgardiomyces. Rhynchosporium s. str. is restricted to species with 1-septate conidia and hooked apical beaks, while Rhynchobrunnera is introduced for species with 1-3-septate, straight conidia, lacking any apical beak. Rhynchosporium graminicola is proposed to replace the name R. commune applied to the barley scald pathogen based on nomenclatural priority. Spermospora is shown to be paraphyletic, representing Spermospora (type: S. subulata), with three new species, S. arrhenatheri, S. loliiphila and S. zeae, and Neospermospora gen. nov. (type: N. avenae). Ypsilina (type: Y. graminea), is shown to be monophyletic, but appears to be of minor importance on cereals. Finally, Vanderaaea gen. nov. (type: V. ammophilae), is introduced as a new coelomycetous fungus occurring on dead leaves of Ammophila arenaria. Citation: Crous PW, Braun U, McDonald BA, Lennox CL, Edwards J, Mann RC, Zaveri A, Linde CC, Dyer PS, Groenewald JZ (2020). Redefining genera of cereal pathogens: Oculimacula, Rhynchosporium and Spermospora. Fungal Systematics and Evolution7: 67-98. doi: 10.3114/fuse.2021.07.04.

  • Phylogeographical analyses reveal global migration patterns Blackwell Publishing Ltd of the barley scald pathogen Rhynchosporium secalis
    2013
    Co-Authors: Pascal L. Zaffarano, Bruce A. Mcdonald, Celeste C. Linde
    Abstract:

    A phylogeographical analysis of the scald pathogen Rhynchosporium secalis was conducted using nuclear DNA sequences from two neutral restriction fragment length polymorphism loci and the mating-type idiomorphs. Approximately 500 isolates sampled from more than 60 field populations from five continents were analysed to infer migration patterns and the demographic history of the fungus. Migration rates among continents were generally low, consistent with earlier reports of significant population subdivision among continents. Northern Europe was mainly a source population for global migration. We hypothesize that the pathogen only recently moved out of its centre of origin, resulting in founder populations that are reproductively isolated due to the contemporary absence of long-distance gene flow

  • invasion of Rhynchosporium commune onto wild barley in the middle east
    Biological Invasions, 2011
    Co-Authors: A Kirosmeles, Bruce A. Mcdonald, Amor Yahyaoui, Don R Gomez, Celeste C. Linde
    Abstract:

    Rhynchosporium commune was recently introduced into the Middle East, presumably with the cultivated host barley (Hordeum vulgare). Middle Eastern populations of R. commune on cultivated barley and wild barley (H. spontaneum) were genetically undifferentiated and shared a high proportion of multilocus haplotypes. This suggests that there has been little selection for host specialization on H. spontaneum, a host population often used as a source of resistance genes introduced into its domesticated counterpart, H. vulgare. Low levels of pathogen genetic diversity on H. vulgare as well as on H. spontaneum, indicate that the pathogen was introduced recently into the Middle East, perhaps through immigration on infected cultivated barley seeds, and then invaded the wild barley population. Although it has not been documented, the introduction of the pathogen into the Middle East may have a negative influence on the biodiversity of native Hordeum species.

  • two new species
    2011
    Co-Authors: Pascal L. Zaffarano, Bruce A. Mcdonald, Celeste C. Linde
    Abstract:

    Rhynchosporium consists of two species, R. secalis and orthosporum. Both are pathogens of grasses with R. secalis infecting a variety of Poaceae hosts and R. orthosporum infecting Dactylis glomerata. Phylogenetic analyses of multilocus DNA sequence data on R. secalis isolates originating from cultivated barley, rye, triticale and other grasses, including Agropyron spp., Bromus diandrus and Hordeum spp., resolved the monophyletic groups into three species according to their respective hosts. Host specificity according to phylogenetic lineages was confirmed with pathogenicity studies. Because R. secalis was described first on rye this name is retained for Rhynchosporium isolates infecting rye and triticale. Rhynchosporium isolates infecting cultivated barley and other Hordeum spp. and Bromus diandrus belong to a distinct species, R. commune. Similarly isolates infecting Agropyron spp. represent a distinct species of Rhynchosporium, namely R. agropyri. A PCR-RFLP assay was developed as a rapid tool for species identification of R. secalis and commune.

  • Phylogeographical analyses reveal global migration patterns of the barley scald pathogen Rhynchosporium secalis.
    Molecular Ecology, 2009
    Co-Authors: Pascal L. Zaffarano, Bruce A. Mcdonald, Celeste C. Linde
    Abstract:

    A phylogeographical analysis of the scald pathogen Rhynchosporium secalis was conducted using nuclear DNA sequences from two neutral restriction fragment length polymorphism loci and the mating-type idiomorphs. Approximately 500 isolates sampled from more than 60 field populations from five continents were analysed to infer migration patterns and the demographic history of the fungus. Migration rates among continents were generally low, consistent with earlier reports of significant population subdivision among continents. Northern Europe was mainly a source population for global migration. We hypothesize that the pathogen only recently moved out of its centre of origin, resulting in founder populations that are reproductively isolated due to the contemporary absence of long-distance gene flow.

Wolfgang Knogge - One of the best experts on this subject based on the ideXlab platform.

  • PFP1, a Gene Encoding an Epc-N Domain-Containing Protein, Is Essential for Pathogenicity of the Barley Pathogen Rhynchosporium
    2016
    Co-Authors: Sylvia Siersleben, Daniel Penselin, Claudia Wenzel, Sylvie Albert, Wolfgang Knogge
    Abstract:

    Scald caused by Rhynchosporium commune is an important foliar disease of barley. Insertion mutagenesis of R. commune gener-ated a nonpathogenic fungal mutant which carries the inserted plasmid in the upstream region of a gene named PFP1. The char-acteristic feature of the gene product is an Epc-N domain. This motif is also found in homologous proteins shown to be compo-nents of histone acetyltransferase (HAT) complexes of fungi and animals. Therefore, PFP1 is suggested to be the subunit of a HAT complex in R. communewith an essential role in the epigenetic control of fungal pathogenicity. Targeted PFP1 disruption also yielded nonpathogenic mutants which showed wild-type-like growth ex planta, except for the occurrence of hyphal swell-ings. Complementation of the deletion mutants with the wild-type gene reestablished pathogenicity and suppressed the hyphal swellings. However, despite wild-type-level PFP1 expression, the complementationmutants did not reach wild-type-level viru-lence. This indicates that the function of the protein complex and, thus, fungal virulence are influenced by a position-affected long-range control of PFP1 expression. Rhynchosporium commune (formerlyRhynchosporium secalis) isa haploid imperfect fungus causing scald, an important foliar disease of barley in all growing areas around the world (1–4). Despite the lack of a sexual stage, the fungus is classified as an Ascomycete on the basis of nucleotide sequence comparisons (5). It is characterized by unusual hemibiotrophic (6), entirely inter

  • comparative analysis of mitochondrial genomes from closely related Rhynchosporium species reveals extensive intron invasion
    Fungal Genetics and Biology, 2014
    Co-Authors: Stefano F F Torriani, Bruce A. Mcdonald, Wolfgang Knogge, Daniel Penselin, Marius Felder, Stefan Taudien, Matthias Platzer, Patrick C. Brunner
    Abstract:

    We sequenced and annotated the complete mitochondrial (mt) genomes of four closely related Rhynchosporium species that diverged ∼14,000-35,000years ago. During this time frame, three of the mt genomes expanded significantly due to an invasion of introns into three genes (cox1, cox2, and nad5). The enlarged mt genomes contained ∼40% introns compared to 8.1% in uninvaded relatives. Many intron gains were accompanied by co-conversion of flanking exonic regions. The comparative analysis revealed a highly variable set of non-intronic, free-standing ORFs of unknown function (uORFs). This is consistent with a rapidly evolving accessory compartment in the mt genome of these closely related species. Only one free-standing uORF was shared among all mt genomes analyzed. This uORF had a mutation rate similar to the core mt protein-encoding genes, suggesting conservation of function among the species. The nucleotide composition of the core protein-encoding genes significantly differed from those of introns and uORFs. The mt mutation rate was 77 times higher than the nuclear mutation rate, indicating that the phylogeny inferred from mt genes may better resolve the phylogenetic relationships among closely related Rhynchosporium species than phylogenies inferred from nuclear genes.

  • Rhynchosporium commune a persistent threat to barley cultivation
    Molecular Plant Pathology, 2012
    Co-Authors: Anna O Avrova, Wolfgang Knogge
    Abstract:

    Summary Rhynchosporium commune is a haploid fungus causing scald or leaf blotch on barley, other Hordeum spp. and Bromus diandrus. Taxonomy Rhynchosporium commune is an anamorphic Ascomycete closely related to the teleomorph Helotiales genera Oculimacula and Pyrenopeziza. Disease symptoms Rhynchosporium commune causes scald-like lesions on leaves, leaf sheaths and ears. Early symptoms are generally pale grey oval lesions. With time, the lesions acquire a dark brown margin with the centre of the lesion remaining pale green or pale brown. Lesions often merge to form large areas around which leaf yellowing is common. Infection frequently occurs in the leaf axil, which can lead to chlorosis and eventual death of the leaf. Life cycle Rhynchosporium commune is seed borne, but the importance of this phase of the disease is not fully understood. Debris from previous crops and volunteers, infected from the stubble from previous crops, are considered to be the most important sources of the disease. Autumn-sown crops can become infected very soon after sowing. Secondary spread of disease occurs mainly through splash dispersal of conidia from infected leaves. Rainfall at the stem extension growth stage is the major environmental factor in epidemic development. Detection and quantification Rhynchosporium commune produces unique beak-shaped, one-septate spores both on leaves and in culture. The development of a specific polymerase chain reaction (PCR) and, more recently, quantitative PCR (qPCR) has allowed the identification of asymptomatic infection in seeds and during the growing season. Disease control The main measure for the control of R. commune is the use of fungicides with different modes of action, in combination with the use of resistant cultivars. However, this is constantly under review because of the ability of the pathogen to adapt to host plant resistance and to develop fungicide resistance.

  • Asexual genetic exchange in the barley pathogen Rhynchosporium secalis
    Phytopathology®, 2007
    Co-Authors: Angus H Forgan, Wolfgang Knogge, Peter A. Anderson
    Abstract:

    ABSTRACT The causal agent of barley scald, Rhynchosporium secalis, is a haploid anamorphic ascomycete with no known sexual stage. Nevertheless, a high degree of genetic variation has been observed in fungal populations on commercial barley cultivars and parasexuality has been suggested to contribute to this variation. In order to test whether asexual genetic exchange can occur, isolates of R. secalis were transformed to hygromycin B resistance or phleomycin resistance. Mixtures of transformants were co-inoculated either on agar or in planta and screened for the occurrence of dual-antibiotic-resistant colonies. No dual-antibiotic-resistant colonies resulted from mixing transformants of different fungal isolates. In contrast, with transformants originating from the same fungal isolate, asexual exchange of markers was demonstrated on agar plates and in planta. This is the first definitive evidence of asexual genetic exchange in R. secalis.

  • amino acid alterations in isoforms of the effector protein nip1 from Rhynchosporium secalis have similar effects on its avirulence and virulence associated activities on barley
    Physiological and Molecular Plant Pathology, 2002
    Co-Authors: Marion Fiegen, Wolfgang Knogge
    Abstract:

    Abstract The secreted effector protein NIP1 from the barley pathogen Rhynchosporium secalis is a specific elicitor of defense reactions in host plants carrying the resistance gene Rrs1. In addition, it has activities associated with fungal virulence; independent of the plant genotype it stimulates the plant plasma membrane H+-ATPase and induces leaf necrosis. Four NIP1 isoforms differing in single amino acid residues were isolated from various naturally occurring fungal strains. All three activities of the protein (race specificity, H+-ATPase stimulation, necrosis induction) were affected by the amino acid alterations in a similar way suggesting that they are mediated through a single plant receptor.

Mark E. Looseley - One of the best experts on this subject based on the ideXlab platform.

  • characterisation of barley landraces from syria and jordan for resistance to Rhynchosporium and identification of diagnostic markers for rrs1rh4
    Theoretical and Applied Genetics, 2020
    Co-Authors: Mark E. Looseley, Max Coulter, Bianca Buttner, Micha Bayer, L Griffe, Kathryn M Wright, Jeannoel Thauvin, Jill Middlefellwilliams, Marta Maluk, Aleksandra Okpo
    Abstract:

    Diagnostic markers for Rrs1Rh4 have been identified by testing for associations between SNPs within the Rrs1 interval in 150 barley genotypes and their resistance to Rhynchosporium commune isolates recognised by lines containing Rrs1. Rhynchosporium or barley scald, caused by the destructive fungal pathogen Rhynchosporium commune, is one of the most economically important diseases of barley in the world. Barley landraces from Syria and Jordan demonstrated high resistance to Rhynchosporium in the field. Genotyping of a wide range of barley cultivars and landraces, including known sources of different Rrs1 genes/alleles, across the Rrs1 interval, followed by association analysis of this genotypic data with resistance phenotypes to R. commune isolates recognised by Rrs1, allowed the identification of diagnostic markers for Rrs1Rh4. These markers are specific to Rrs1Rh4 and do not detect other Rrs1 genes/alleles. The Rrs1Rh4 diagnostic markers represent a resource that can be exploited by breeders for the sustainable deployment of varietal resistance in new cultivars. Thirteen out of the 55 most resistant Syrian and Jordanian landraces were shown to contain markers specific to Rrs1Rh4. One of these lines came from Jordan, with the remaining 12 lines from different locations in Syria. One of the Syrian landraces containing Rrs1Rh4 was also shown to have Rrs2. The remaining landraces that performed well against Rhynchosporium in the field are likely to contain other resistance genes and represent an important novel resource yet to be exploited by European breeders.

  • characterisation of barley resistance to Rhynchosporium on chromosome 6hs
    Theoretical and Applied Genetics, 2019
    Co-Authors: Max Coulter, Mark E. Looseley, Gunther Schweizer, Bianca Buttner, Kerstin Hofmann, Micha Bayer, Luke Ramsay, Robbie Waugh, Anna O Avrova
    Abstract:

    Major resistance gene to Rhynchosporium, Rrs18, maps close to the telomere on the short arm of chromosome 6H in barley. Rhynchosporium or barley scald caused by a fungal pathogen Rhynchosporium commune is one of the most destructive and economically important diseases of barley in the world. Testing of Steptoe × Morex and CIho 3515 × Alexis doubled haploid populations has revealed a large effect QTL for resistance to R. commune close to the telomere on the short arm of chromosome 6H, present in both populations. Mapping markers flanking the QTL from both populations onto the 2017 Morex genome assembly revealed a Rhynchosporium resistance locus independent of Rrs13 that we named Rrs18. The causal gene was fine mapped to an interval of 660 Kb using Steptoe × Morex backcross 1 S2 and S3 lines with molecular markers developed from Steptoe exome capture variant calling. Sequencing RNA from CIho 3515 and Alexis revealed that only 4 genes within the Rrs18 interval were transcribed in leaf tissue with a serine/threonine protein kinase being the most likely candidate for Rrs18.

  • resistance to Rhynchosporium commune in a collection of european spring barley germplasm
    Theoretical and Applied Genetics, 2018
    Co-Authors: Mark E. Looseley, Malcolm Macaulay, Bianca Buttner, L Griffe, Kathryn M Wright, Jill Middlefellwilliams, Hazel Bull, Paul Shaw, Allan Booth
    Abstract:

    Association analyses of resistance to Rhynchosporium commune in a collection of European spring barley germplasm detected 17 significant resistance quantitative trait loci. The most significant association was confirmed as Rrs1. Rhynchosporium commune is a fungal pathogen of barley which causes a highly destructive and economically important disease known as Rhynchosporium. Genome-wide association mapping was used to investigate the genetic control of host resistance to R. commune in a collection of predominantly European spring barley accessions. Multi-year disease nursery field trials revealed 8 significant resistance quantitative trait loci (QTL), whilst a separate association mapping analysis using historical data from UK national and recommended list trials identified 9 significant associations. The most significant association identified in both current and historical data sources, collocated with the known position of the major resistance gene Rrs1. Seedling assays with R. commune single-spore isolates expressing the corresponding avirulence protein NIP1 confirmed that this locus is Rrs1. These results highlight the significant and continuing contribution of Rrs1 to host resistance in current elite spring barley germplasm. Varietal height was shown to be negatively correlated with disease severity, and a resistance QTL was identified that co-localised with the semi-dwarfing gene sdw1, previously shown to contribute to disease escape. The remaining QTL represent novel resistances that are present within European spring barley accessions. Associated markers to Rrs1 and other resistance loci, identified in this study, represent a set of tools that can be exploited by breeders for the sustainable deployment of varietal resistance in new cultivars.

  • genetic mapping of resistance to Rhynchosporium commune and characterisation of early infection in a winter barley mapping population
    Euphytica, 2015
    Co-Authors: Mark E. Looseley, R. Keith, D. Harrap, D C Guy, G Barralbaron, A Thirugnanasambandam, Peter Werner, A C Newton
    Abstract:

    The genetic basis of resistance to Rhynchosporium commune was investigated in a winter barley mapping population derived from a cross between cultivars Saffron (moderately susceptible) and Retriever (moderately resistant). Resistance was assessed in field trials through total infection (measured using qPCR), and visible disease symptoms. Phenotypic correlations between both methods of assessing disease severity were high. QTL mapping from three years of field trials identified five significant QTL effects. One QTL effect on chromosome 2H confirms a previously reported resistance from a population derived from the spring cultivar Cocktail and a winter parent derived from the cultivars Pearl and Cocktail. Another QTL effect on 3H corresponds to the reported position of major resistance gene Rrs1. An effect was detected at the mapped position of the semi-dwarfing gene sdw-1 despite the fact that neither parent has the semi-dwarf phenotype. Of the remaining two QTL effects, one on 6H may represent a previously reported Rhynchosporium resistance (QTLTritonRrs6H271), whilst the final QTL, represents a novel resistance. In addition, interactions during early infection stages in the parental lines were studied by confocal microscopy of detached leaves inoculated with a GFP-expressing R. commune isolate. This approach identified a number of major differences in fungal growth morphology between the resistant and susceptible parent.

  • Genetic basis of control of Rhynchosporium secalis infection and symptom expression in barley
    Euphytica, 2011
    Co-Authors: Mark E. Looseley, Adrian C. Newton, Bruce D.l. Fitt, Simon D. Atkins, Bart A. Fraaije, William T. B. Thomas, R. Keith, Malcolm Macaulay, J. Lynott, D. Harrap
    Abstract:

    The genetic basis of several different components of resistance to Rhynchosporium secalis in barley was investigated in a mapping population derived from a cross between winter and spring barley types. Both the severity of visual disease symptoms and amount of R. secalis DNA in leaf tissues were assessed in field trials in Scotland in the 2007/2008 and 2008/2009 growing seasons. Relative expression of symptoms was defined as the residual values from a linear regression of amount of R. secalis DNA against visual plot disease score at GS 50. Amount of R. secalis DNA and visual disease score were highly correlated traits and identified nearly identical QTL. The genetic control of relative expression of symptoms was less clear. However, a QTL on chromosome 7H was identified as having a significant effect on the expression of visual disease symptoms relative to overall amount of R. secalis colonisation.

Bianca Buttner - One of the best experts on this subject based on the ideXlab platform.

  • characterisation of barley landraces from syria and jordan for resistance to Rhynchosporium and identification of diagnostic markers for rrs1rh4
    Theoretical and Applied Genetics, 2020
    Co-Authors: Mark E. Looseley, Max Coulter, Bianca Buttner, Micha Bayer, L Griffe, Kathryn M Wright, Jeannoel Thauvin, Jill Middlefellwilliams, Marta Maluk, Aleksandra Okpo
    Abstract:

    Diagnostic markers for Rrs1Rh4 have been identified by testing for associations between SNPs within the Rrs1 interval in 150 barley genotypes and their resistance to Rhynchosporium commune isolates recognised by lines containing Rrs1. Rhynchosporium or barley scald, caused by the destructive fungal pathogen Rhynchosporium commune, is one of the most economically important diseases of barley in the world. Barley landraces from Syria and Jordan demonstrated high resistance to Rhynchosporium in the field. Genotyping of a wide range of barley cultivars and landraces, including known sources of different Rrs1 genes/alleles, across the Rrs1 interval, followed by association analysis of this genotypic data with resistance phenotypes to R. commune isolates recognised by Rrs1, allowed the identification of diagnostic markers for Rrs1Rh4. These markers are specific to Rrs1Rh4 and do not detect other Rrs1 genes/alleles. The Rrs1Rh4 diagnostic markers represent a resource that can be exploited by breeders for the sustainable deployment of varietal resistance in new cultivars. Thirteen out of the 55 most resistant Syrian and Jordanian landraces were shown to contain markers specific to Rrs1Rh4. One of these lines came from Jordan, with the remaining 12 lines from different locations in Syria. One of the Syrian landraces containing Rrs1Rh4 was also shown to have Rrs2. The remaining landraces that performed well against Rhynchosporium in the field are likely to contain other resistance genes and represent an important novel resource yet to be exploited by European breeders.

  • characterisation of barley resistance to Rhynchosporium on chromosome 6hs
    Theoretical and Applied Genetics, 2019
    Co-Authors: Max Coulter, Mark E. Looseley, Gunther Schweizer, Bianca Buttner, Kerstin Hofmann, Micha Bayer, Luke Ramsay, Robbie Waugh, Anna O Avrova
    Abstract:

    Major resistance gene to Rhynchosporium, Rrs18, maps close to the telomere on the short arm of chromosome 6H in barley. Rhynchosporium or barley scald caused by a fungal pathogen Rhynchosporium commune is one of the most destructive and economically important diseases of barley in the world. Testing of Steptoe × Morex and CIho 3515 × Alexis doubled haploid populations has revealed a large effect QTL for resistance to R. commune close to the telomere on the short arm of chromosome 6H, present in both populations. Mapping markers flanking the QTL from both populations onto the 2017 Morex genome assembly revealed a Rhynchosporium resistance locus independent of Rrs13 that we named Rrs18. The causal gene was fine mapped to an interval of 660 Kb using Steptoe × Morex backcross 1 S2 and S3 lines with molecular markers developed from Steptoe exome capture variant calling. Sequencing RNA from CIho 3515 and Alexis revealed that only 4 genes within the Rrs18 interval were transcribed in leaf tissue with a serine/threonine protein kinase being the most likely candidate for Rrs18.

  • resistance to Rhynchosporium commune in a collection of european spring barley germplasm
    Theoretical and Applied Genetics, 2018
    Co-Authors: Mark E. Looseley, Malcolm Macaulay, Bianca Buttner, L Griffe, Kathryn M Wright, Jill Middlefellwilliams, Hazel Bull, Paul Shaw, Allan Booth
    Abstract:

    Association analyses of resistance to Rhynchosporium commune in a collection of European spring barley germplasm detected 17 significant resistance quantitative trait loci. The most significant association was confirmed as Rrs1. Rhynchosporium commune is a fungal pathogen of barley which causes a highly destructive and economically important disease known as Rhynchosporium. Genome-wide association mapping was used to investigate the genetic control of host resistance to R. commune in a collection of predominantly European spring barley accessions. Multi-year disease nursery field trials revealed 8 significant resistance quantitative trait loci (QTL), whilst a separate association mapping analysis using historical data from UK national and recommended list trials identified 9 significant associations. The most significant association identified in both current and historical data sources, collocated with the known position of the major resistance gene Rrs1. Seedling assays with R. commune single-spore isolates expressing the corresponding avirulence protein NIP1 confirmed that this locus is Rrs1. These results highlight the significant and continuing contribution of Rrs1 to host resistance in current elite spring barley germplasm. Varietal height was shown to be negatively correlated with disease severity, and a resistance QTL was identified that co-localised with the semi-dwarfing gene sdw1, previously shown to contribute to disease escape. The remaining QTL represent novel resistances that are present within European spring barley accessions. Associated markers to Rrs1 and other resistance loci, identified in this study, represent a set of tools that can be exploited by breeders for the sustainable deployment of varietal resistance in new cultivars.

Related terms

Rhynchosporium - 15 days free trial to Access Experts & Abstracts