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Timothy L. Friesen - One of the best experts on this subject based on the ideXlab platform.
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Four reference quality genome assemblies of Pyrenophora teres f. maculata: a resource for studying the barley spot form net blotch interaction.
Molecular plant-microbe interactions : MPMI, 2020Co-Authors: Nathan A. Wyatt, Timothy L. FriesenAbstract:Pyrenophora teres is the causal agent of net blotch, the most devastating foliar disease of barley. In nature, net blotch is seen in two forms, net form net blotch, caused by P. teres f. teres, and spot form net blotch, caused by P. teres f. maculata. To date, 11 P. teres f. teres genomes have been sequenced and deposited on publicly available repositories, but only one P. teres f. maculata genome has been publicly deposited. Here we present four additional reference quality full genome sequences of P. teres f. maculata isolates with good geographical and phenotypic diversity with accompanying RNA sequencing-based genome annotations. These additional P. teres f. maculata genomes will aid in the understanding of the genomic complexities of this important barley pathogen.
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research advances in the Pyrenophora teres barley interaction
Molecular Plant Pathology, 2020Co-Authors: Shaun J. Clare, Nathan A. Wyatt, Robert Brueggeman, Timothy L. FriesenAbstract:Pyrenophora teres f. teres and P. teres f. maculata are significant pathogens that cause net blotch of barley. An increased number of loci involved in P. teres resistance or susceptibility responses of barley as well as interacting P. teres virulence effector loci have recently been identified through biparental and association mapping studies of both the pathogen and host. Characterization of the resistance/susceptibility loci in the host and the interacting effector loci in the pathogen will provide a path for targeted gene validation for better-informed release of resistant barley cultivars. This review assembles concise consensus maps for all loci published for both the host and pathogen, providing a useful resource for the community to be used in pathogen characterization and barley breeding for resistance to both forms of P. teres.
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Research advances in the Pyrenophora teres–barley interaction
Molecular plant pathology, 2019Co-Authors: Shaun J. Clare, Nathan A. Wyatt, Robert Brueggeman, Timothy L. FriesenAbstract:Pyrenophora teres f. teres and P. teres f. maculata are significant pathogens that cause net blotch of barley. An increased number of loci involved in P. teres resistance or susceptibility responses of barley as well as interacting P. teres virulence effector loci have recently been identified through biparental and association mapping studies of both the pathogen and host. Characterization of the resistance/susceptibility loci in the host and the interacting effector loci in the pathogen will provide a path for targeted gene validation for better-informed release of resistant barley cultivars. This review assembles concise consensus maps for all loci published for both the host and pathogen, providing a useful resource for the community to be used in pathogen characterization and barley breeding for resistance to both forms of P. teres.
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Characterizing the Pyrenophora teres f. maculata-Barley Interaction Using Pathogen Genetics.
G3 (Bethesda Md.), 2017Co-Authors: Steven A. Carlsen, Nathan A. Wyatt, Robert Brueggeman, Justin D. Faris, Anjan Neupane, Jonathan K. Richards, Timothy L. FriesenAbstract:Pyrenophora teres f. maculata is the cause of the foliar disease spot form net blotch (SFNB) on barley. To evaluate pathogen genetics underlying the P. teres f. maculata –barley interaction, we developed a 105-progeny population by crossing two globally diverse isolates, one from North Dakota and the other from Western Australia. Progeny were phenotyped on a set of four barley genotypes showing a differential reaction to the parental isolates, then genotyped using a restriction site-associated-genotype-by-sequencing (RAD-GBS) approach. Genetic maps were developed for use in quantitative trait locus (QTL) analysis to identify virulence-associated QTL. Six QTL were identified on five different linkage groups and individually accounted for 20–37% of the disease variation, with the number of significant QTL ranging from two to four for the barley genotypes evaluated. The data presented demonstrate the complexity of virulence involved in the P. teres f. maculata –barley pathosystem and begins to lay the foundation for understanding this important interaction.
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Characterizing the Pyrenophora teres f. maculata–Barley Interaction Using Pathogen Genetics
Genetics Society of America, 2017Co-Authors: Steven A. Carlsen, Nathan A. Wyatt, Justin D. Faris, Anjan Neupane, Jonathan K. Richards, Robert S. Brueggeman, Timothy L. FriesenAbstract:Pyrenophora teres f. maculata is the cause of the foliar disease spot form net blotch (SFNB) on barley. To evaluate pathogen genetics underlying the P. teres f. maculata–barley interaction, we developed a 105-progeny population by crossing two globally diverse isolates, one from North Dakota and the other from Western Australia. Progeny were phenotyped on a set of four barley genotypes showing a differential reaction to the parental isolates, then genotyped using a restriction site-associated-genotype-by-sequencing (RAD-GBS) approach. Genetic maps were developed for use in quantitative trait locus (QTL) analysis to identify virulence-associated QTL. Six QTL were identified on five different linkage groups and individually accounted for 20–37% of the disease variation, with the number of significant QTL ranging from two to four for the barley genotypes evaluated. The data presented demonstrate the complexity of virulence involved in the P. teres f. maculata–barley pathosystem and begins to lay the foundation for understanding this important interaction
Hugh Wallwork - One of the best experts on this subject based on the ideXlab platform.
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Initial characterisation of phytotoxic proteins isolated from Pyrenophora teres
Physiological and Molecular Plant Pathology, 2008Co-Authors: A. Sarpeleh, Hugh Wallwork, Max E. Tate, David E. A. Catcheside, Amanda J. AbleAbstract:Pyrenophora teres, the causal agent of net blotch of barley (Hordeum vulgare L.), induces distinctive long dark brown lesions (the net form) or dark brown spots (the spot form), both with surrounding chlorosis. Proteins isolated from P. teres f. teres (the net form) and P. teres f. maculata (the spot form) induce host-specific necrosis. In this study, the activity of these proteinaceous toxins was further characterised. The toxins were heat stable and their activity in planta was temperature and light dependent suggesting a role in targeting metabolically active and light-dependent organelles such as the chloroplast. In addition, proteinase K treatment after toxin treatment did not affect symptom induction by the toxins suggesting they are actively internalised. Adult barley plants were less sensitive to the toxins than younger plants, highlighting a potential adult resistance mechanism. Characterisation of these host-specific proteinaceous toxins produced by P. teres further assists our understanding of the role of such selective toxins in disease induction in plants.
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Diagnostic microsatellite markers for the barley net blotch pathogens, Pyrenophora teres f. maculata and Pyrenophora teres f. teres
Australasian Plant Pathology, 2008Co-Authors: Felicity J. Keiper, Milica Grcic, E. Capio, Hugh WallworkAbstract:The barley net blotch pathogen Pyrenophora teres occurs in two forms, evident as spot (P. teres f. maculata) or net (P. teres f. teres) type symptoms. The two forms can be difficult to differentiate based on disease symptoms or spore morphology. Here we report nine simple sequence repeat markers that reveal differences between the two forms, providing diagnostic markers that are potentially useful.
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Characterisation of low molecular weight phytotoxins isolated from Pyrenophora teres
Physiological and Molecular Plant Pathology, 2008Co-Authors: A. Sarpeleh, Hugh Wallwork, Max E. Tate, David E. A. Catcheside, Amanda J. AbleAbstract:Abstract We have previously shown that pooled low molecular weight compounds (LMWCs) isolated from culture filtrates of both forms of the barley net blotch pathogen Pyrenophora teres cause chlorosis. In this study, the LMWCs were further characterised and individually identified. The LMWCs were non-host selective compounds and their activity in planta was temperature and light-dependent suggesting a role in targeting metabolism and light-dependent organelles such as the chloroplast. Although the previously characterised toxins N -(2-amino-2-carboxyethyl) aspartic acid (Toxin A), 1-(2-amino-2-carboxyethyl)-6-carboxy-3-carboxymethyl-2-piperazinone (Toxin B), and N -[2-(2-amino-2-carboxy ethyl-amino)-2-carboxyethyl] aspartic acid (Toxin C) were identified, a number of other chlorosis-causing compounds were also isolated. Here, we report the first isolation of aspergillomarasmine B from P. teres media filtrates as well as the isolation and description of a unique u.v.-absorbing phytotoxic LMWC which appears to be a reductive conjugation of the α-keto acid of phenylalanine with Toxin A.
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development of sequence tagged microsatellites for the barley net blotch pathogen Pyrenophora teres
Molecular Ecology Notes, 2007Co-Authors: Felicity J. Keiper, Milica Grcic, E. Capio, Hugh WallworkAbstract:A modified sequenced-tagged microsatellite (STM) profiling procedure was used to develop 80 STMs for the barley net blotch pathogen, Pyrenophora teres. Of these, 60 STMs amplified 67 loci in one or both of the spot (P. teres f. maculata) and net (P. teres f. teres) forms of the pathogen. When screened on six field-sampled isolates of each pathogen form, 25 STMs revealed 26 polymorphic loci, with an average of 3.2 ± 1.0 alleles and mean gene diversity of 0.59 ± 0.12.
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Genetic differentiation in Pyrenophora teres populations measured with AFLP markers.
Mycological research, 2007Co-Authors: Marjo Serenius, Hugh Wallwork, Outi Manninen, Kevin WilliamsAbstract:The genetic structure and occurrence of mating types and forms of Pyrenophora teres, the causal agent of net blotch on barley, was studied among 278 isolates collected from the northern hemisphere and from Australia. Genetic differentiation was high (F(CT) 0.238, P=0.002) between P. teres f. teres (PTT) isolates originating from Northern Europe, North America, Russia and Australia. The P. teres population in Australia was clearly divided into two subgroups (F(CT) 0.793, P
Emil Y J. A. Taylor - One of the best experts on this subject based on the ideXlab platform.
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Scorpion ARMS primers for SNP real‐time PCR detection and quantification of Pyrenophora teres
Molecular plant pathology, 2001Co-Authors: Jayne A. Bates, Emil Y J. A. TaylorAbstract:summary We have developed a quantitative PCR detection method that can be used to determine the seed infection levels of Pyrenophora teres, a seed-borne fungal pathogen of barley. This method uses Scorpion Amplified Refractory Mutation System (ARMS) technology with real-time PCR detection. Scorpion ARMS primers were designed and optimized such that a single nucleotide base mismatch in the primer sequence could distinguish P. teres from P. graminea, a closely related seed-borne pathogen of barley. It is necessary to distinguish between these two agriculturally important pathogens since different disease management decisions are made, based on the presence and level of infection measured for each. The advance in development of sensitive and specific fluorescent probes has enabled the current PCR test to detect Pyrenophora spp. pathogenic on barley to be enhanced with the advantage that it can now specifically detect P. teres in a single reaction, whilst previously, two reactions were required to discriminate P. teres from P. graminea.
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scorpion arms primers for snp real time pcr detection and quantification of Pyrenophora teres
Molecular Plant Pathology, 2001Co-Authors: Jayne A. Bates, Emil Y J. A. TaylorAbstract:summary We have developed a quantitative PCR detection method that can be used to determine the seed infection levels of Pyrenophora teres, a seed-borne fungal pathogen of barley. This method uses Scorpion Amplified Refractory Mutation System (ARMS) technology with real-time PCR detection. Scorpion ARMS primers were designed and optimized such that a single nucleotide base mismatch in the primer sequence could distinguish P. teres from P. graminea, a closely related seed-borne pathogen of barley. It is necessary to distinguish between these two agriculturally important pathogens since different disease management decisions are made, based on the presence and level of infection measured for each. The advance in development of sensitive and specific fluorescent probes has enabled the current PCR test to detect Pyrenophora spp. pathogenic on barley to be enhanced with the advantage that it can now specifically detect P. teres in a single reaction, whilst previously, two reactions were required to discriminate P. teres from P. graminea.
Michael G. Milgroom - One of the best experts on this subject based on the ideXlab platform.
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Genetic structure of Pyrenophora teres populations determined with random amplified polymorphic DNA markers
Canadian Journal of Botany, 1994Co-Authors: Tobin L. Peever, Michael G. MilgroomAbstract:The genetic structure of Pyrenophora teres, an ascomycete fungus that causes net blotch of barley, was examined using random amplified polymorphic DNA (RAPD) markers. Twenty-seven random oligonucleotide primers were screened against DNA from 16 isolates of P. teres of diverse geographic origin. Five primers gave scorable, reproducible DNA products (bands) suitable for population genetic studies. Genetic analyses of bands produced by two of the primers revealed single locus segregation in three of four crosses, indicating that these RAPDs can be interpreted as alleles at genetic loci. Allele frequencies were determined for 10 putative RAPD loci from five primers in 22–35 isolates of P. teres sampled from each of five geographically separated populations in Canada, Germany, and the U.S.A. Eight RAPD loci were polymorphic in at least one population and two loci were monomorphic in all five populations. Variation in allele frequencies (allelic diversity) among the five populations was partitioned into within-...
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Lack of correlation between fitness and resistance to sterol biosynthesis-inhibiting fungicides in Pyrenophora teres
Phytopathology, 1994Co-Authors: Tobin L. Peever, Michael G. MilgroomAbstract:Fitness costs associated with resistance to sterol biosynthesis-inhibiting fungicides (SBIs) were investigated by calculating correlations between SBI-resistance phenotypes and fitness phenotypes in Pyrenophora teres. Correlations between resistance to the SBIs triadimenol and propiconazole and two components of fitness were estimated with P. teres isolates randomly sampled from populations in North Dalcota and Bavaria, Germany. The fitness components, latent period (the time from inoculation to the first appearance of a conidium) and sporulation (total sporulation per lesion), were determined quantitatively with detached barley leaf sections inoculated with P. teres conidia in the greenhouse [...]
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Inheritance of triadimenol resistance in Pyrenophora teres
Phytopathology, 1992Co-Authors: Tobin L. Peever, Michael G. MilgroomAbstract:Progeny from crosses between isolates of Pyrenophora teres sensitive and resistant to the sterol demethylation-inhibiting fungicide (DMI) triadimenol revealed that resistance segregates at a single, major genetic locus. Crosses between isolates from different geographic regions (Canada, New Zealand, and the United States) indicated a lack of fertility barriers between isolates from these regions and indicated that resistance to tri- adimenol is conferred by alleles at the same genetic locus (...)
Felicity J. Keiper - One of the best experts on this subject based on the ideXlab platform.
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A first genome assembly of the barley fungal pathogen Pyrenophora teres f. teres.
Genome biology, 2010Co-Authors: Simon R. Ellwood, Felicity J. Keiper, Zhibing Lai, Zhaohui Liu, Richard P. Oliver, Robert A. Syme, James K. Hane, Caroline S. Moffat, Timothy L. FriesenAbstract:Background: Pyrenophora teres f. teres is a necrotrophic fungal pathogen and the cause of one of barley’s most important diseases, net form of net blotch. Here we report the first genome assembly for this species based solely on short Solexa sequencing reads of isolate 0-1. The assembly was validated by comparison to BAC sequences, ESTs, orthologous genes and by PCR, and complemented by cytogenetic karyotyping and the first genome-wide genetic map for P. teres f. teres. Results: The total assembly was 41.95 Mbp and contains 11,799 gene models of 50 amino acids or more. Comparison against two sequenced BACs showed that complex regions with a high GC content assembled effectively. Electrophoretic karyotyping showed distinct chromosomal polymorphisms between isolates 0-1 and 15A, and cytological karyotyping confirmed the presence of at least nine chromosomes. The genetic map spans 2477.7 cM and is composed of 243 markers in 25 linkage groups, and incorporates simple sequence repeat markers developed from the assembly. Among predicted genes, non-ribosomal peptide synthetases and efflux pumps in particular appear to have undergone a P. teres f. teres-specific expansion of non-orthologous gene families. Conclusions: This study demonstrates that paired-end Solexa sequencing can successfully capture coding regions of a filamentous fungal genome. The assembly contains a plethora of predicted genes that have been implicated in a necrotrophic lifestyle and pathogenicity and presents a significant resource for examining the bases for P. teres f. teres pathogenicity. Background Net blotch of barley (Hordeum vulgare) is caused by Pyrenophora teres Drechsler (anamorph Drechslera teres [Sacc.] Shoem.). P. teres is an ascomycete within the class Dothideomycetes and order Pleosporales. This order contains plant pathogens responsible for many necrotrophic diseases in crops, including members of the genera Ascochyta, Cochliobolus, Pyrenophora, Leptosphaeria and Stagonospora. Net blotch is a major disease worldwide that causes barley yield losses of 10 to 40%, although complete loss can occur with susceptible cultivars in the absence of fungicide treatment [1]. In Australia the value of disease control is estimated at $246 million annually with average direct costs of $62 million
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Diagnostic microsatellite markers for the barley net blotch pathogens, Pyrenophora teres f. maculata and Pyrenophora teres f. teres
Australasian Plant Pathology, 2008Co-Authors: Felicity J. Keiper, Milica Grcic, E. Capio, Hugh WallworkAbstract:The barley net blotch pathogen Pyrenophora teres occurs in two forms, evident as spot (P. teres f. maculata) or net (P. teres f. teres) type symptoms. The two forms can be difficult to differentiate based on disease symptoms or spore morphology. Here we report nine simple sequence repeat markers that reveal differences between the two forms, providing diagnostic markers that are potentially useful.
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development of sequence tagged microsatellites for the barley net blotch pathogen Pyrenophora teres
Molecular Ecology Notes, 2007Co-Authors: Felicity J. Keiper, Milica Grcic, E. Capio, Hugh WallworkAbstract:A modified sequenced-tagged microsatellite (STM) profiling procedure was used to develop 80 STMs for the barley net blotch pathogen, Pyrenophora teres. Of these, 60 STMs amplified 67 loci in one or both of the spot (P. teres f. maculata) and net (P. teres f. teres) forms of the pathogen. When screened on six field-sampled isolates of each pathogen form, 25 STMs revealed 26 polymorphic loci, with an average of 3.2 ± 1.0 alleles and mean gene diversity of 0.59 ± 0.12.
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Development of sequence‐tagged microsatellites for the barley net blotch pathogen, Pyrenophora teres
Molecular Ecology Notes, 2006Co-Authors: Felicity J. Keiper, Milica Grcic, E. Capio, Hugh WallworkAbstract:A modified sequenced-tagged microsatellite (STM) profiling procedure was used to develop 80 STMs for the barley net blotch pathogen, Pyrenophora teres. Of these, 60 STMs amplified 67 loci in one or both of the spot (P. teres f. maculata) and net (P. teres f. teres) forms of the pathogen. When screened on six field-sampled isolates of each pathogen form, 25 STMs revealed 26 polymorphic loci, with an average of 3.2 ± 1.0 alleles and mean gene diversity of 0.59 ± 0.12.
