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Hugh Wallwork - One of the best experts on this subject based on the ideXlab platform.
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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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Proteinaceous Metabolites from Pyrenophora teres Contribute to Symptom Development of Barley Net Blotch
Phytopathology, 2007Co-Authors: A. Sarpeleh, Hugh Wallwork, Max E. Tate, David E. A. Catcheside, Amanda J. AbleAbstract:ABSTRACT Pyrenophora teres, the causal agent of Net Blotch of barley (Hordeum vulgare L.), induces a combination of necrosis and extensive chlorosis in susceptible barley cultivars. Cell-free filtrates from both Net and spot forms of P. teres; P. teres f. sp. teres, and P. teres f. sp. maculata were found to contain phytotoxic low molecular weight compounds (LMWCs) and proteinaceous metabolites which appear to be responsible for different components of the symptoms induced by the two forms of the pathogen in a susceptible cultivar of barley (cv. Sloop). Proteins induced only brown necrotic spots or lesions similar to those induced by the pathogens 72 h after inoculation. In contrast, LMWCs induced general chlorosis seen 240 h after inoculation but not the localized necrosis. Neither hydrolyzed or heat- or protease-treated proteinaceous metabolites induced the symptoms. This is the first report of the involvement of proteins produced by P. teres in symptom development during Net Blotch disease of barley.
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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.
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Development and use of an assay based on the polymerase chain reaction that differentiates the pathogens causing spot form and Net form of Net Blotch of barley
Australasian Plant Pathology, 2001Co-Authors: K. J. Williams, C. Smyl, A. Lichon, K. Y. Wong, Hugh WallworkAbstract:Two forms of barley Net Blotch are caused by different formae of the fungus Pyrenophora teres and both are economically important pathogens. The spot form of the Net Blotch fungus (P. teres f. maculata) and the Net form of the Net Blotch fungus (P. teres f. teres) cause the lesion types indicated by their disease names, although symptom overlap and similar spore morphology can make identification difficult. Randomly amplified polymorphic DNA fragments differentiated the two forms of Pyrenophora. Polymorphic bands were cloned and sequenced to develop specific primer sets. A simple assay based on the polymerase chain reaction was developed and can identify the Pyrenophora formae causing disease symptoms directly from infected plant tissues in a single multiplex reaction. The assay was validated using amplified fragment length polymorphism genotyping of isolates and was shown to be more accurate than reliance on symptom expression. This assay can now be used for routine diagnosis, epidemiological studies and resistance breeding, where correct identification of each pathogen is critical.
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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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, 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 in 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.[Formula: see text] Copyright © 2020 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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identification of pyrenophora teres f maculata causal agent of spot type Net Blotch of barley in north dakota
Plant Disease, 2010Co-Authors: Zhaohui Liu, Timothy L. FriesenAbstract:Net Blotch of barley (Hordeum vulgare L.) caused by the fungus Pyrenophora teres (anamorph Drechslera teres) is found in two forms, Net form Net Blotch (NFNB) and spot form Net Blotch (SFNB). When inoculated on susceptible varieties, P. teres f. teres produces lesions with a characteristic Net-like pattern surrounded by necrosis or chlorosis (NFNB), whereas P. teres f. maculata produces lesions consisting of spots surrounded by necrosis or chlorosis (SFNB). Recently, epidemics of SFNB have occurred throughout the world (4). Currently, Net Blotch is a significant foliar disease of barley in the North Dakota-Northwestern Minnesota agricultural region, a leading barley-production area. Diseased barley leaf tissue was collected annually from 2004 to 2008 in Fargo and Langdon, ND. Diseased leaves were incubated to promote sporulation. Ten single-spore isolates of P. teres collected from each location each year were tested for virulence by inoculation on 20 commonly used barley Net Blotch differential lines. Among the 100 isolates collected, one isolate collected in Fargo in 2006 (FGOH06Pt-8) and one isolate collected in Langdon in 2008 (LDNH08Pt-4) were identified as P. teres f. maculata due to their induction of spot-type lesions across the differential set. Conidial morphology of the two isolates was similar to P. teres f. teres isolates. A pathogenicity test of all isolates was performed on regional barley cvs. Tradition, Robust, and Lacey as well as barley lines Rika and Kombar (1) as previously described (3). The Net form isolate 0-1 and spot form isolate DEN2.6 (obtained from B. Steffenson, University of Minnesota) were used as controls. The P. teres f. teres isolate 0-1 produced typical Net type symptoms on all barley lines except the resistant line Rika, in which only small, dark spots were observed. DEN2.6 produced pin-point spot-like lesions with an extensive yellow halo on Robust, Lacey, Rika, and Kombar, but without chlorosis on Tradition. The two newly identified isolates induced elliptical spot-type lesions measuring 3 × 6 mm, larger than those produced by P. teres f. maculata isolate DEN 2.6, suggesting a higher level of virulence. We constructed a neighbor-joining phylogeNetic tree using ClustalW2 ( http://www.ebi.ac.uk/ ) based on sequence identity of the internal transcribed spacer (ITS) region from 0-1 (GenBank No. GU014819), DEN2.6 (GenBank No. GU014820), FGOH06Pt-8 (GenBank No. GU014821), and LDNH08Pt-4 (GenBank No. GU014822) as well as P. teres f. maculata, P. teres f. teres, and P. tritici-repentis (causal agent of tan spot of wheat) accessions obtained from GenBank (2). All P. teres isolates clustered together and were clearly separated from the P. tritici-repentis cluster. Isolates FGOH06Pt-8 and LDNH08Pt-4 had identical ITS sequences and differed from DEN2.6 by only a single nucleotide. To our knowledge, this is the first report of P. teres f. maculata in North Dakota. Resistance to SFNB should now be considered in local barley breeding programs and cultivar releases. Reference: (1) M. Abu Qamar. Theor. Appl. GeNet. 117:1261, 2008. (2) R. M. Andrie et al. Fungal GeNet. Biol. 45:363, 2008. (3) Z. Lai et al. Fungal GeNet. Biol. 44:323, 2007. (4) M. S. McLean et al. Crop Pasture Sci. 60:303, 2009.
Felicity J. Keiper - One of the best experts on this subject based on the ideXlab platform.
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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.
Brahim Ezzahiri - One of the best experts on this subject based on the ideXlab platform.
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Net Blotch in semi-arid regions of Morocco II
Field Crops Research, 2001Co-Authors: Brahim El Yousfi, Brahim EzzahiriAbstract:Abstract Net Blotch incited by Pyrenophora teres f. teres is an important constraint for barley production in the semi-arid regions of Morocco, reaching epidemic proportions under favorable weather conditions. In this study, we generated 480 epidemics. These epidemics were characterized at five sites and for six different varieties with plants either inoculated by the pathogen or treated with fungicide tilt (propiconazle) 250 a.i. ha−1. The study was conducted in two growing seasons (1995–1996 and 1996–1997). Disease severity and area under the disease progress curve (AUDPC) were related to grain yield. Critical-point model (CPM) and multiple-point model (MPM) did not explain the yield variability encountered and were not investigated further. For the same reason, the relationship between the AUDPC and yield was discarded. Disease effect on yield loss was closely related to yield potential in each growing season, and could not be used to predict yield or yield losses. Estimated yield losses due to Net Blotch varied between 14 and 29% with resistant varieties out yielding susceptible varieties by 39% when there was no disease control and by 56% under fungicide treatment. Varietal resistance is essential to the control of barley Net Blotch. A response surface model based on grain yield, AUDPC and growth stage explained most of the yield variability (R2=0.94). This model was validated with 13 barley varieties and two mixtures. The fitting of this response surface model predicted grain yields within ±200 kg ha−1 when tested from booting to flowering stages.
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Net Blotch in semi arid regions of Morocco. I Epidemiology
Field Crops Research, 2001Co-Authors: Brahim El Yousfi, Brahim EzzahiriAbstract:Abstract Net Blotch caused by Pyrenophora teres F. teres , is one of the important diseases in Moroccan barley fields. Contributing factors include the lack of adequate disease and crop management. Furthermore when agricultural techniques were recommended without disease control, objectives were seldom reached and resulted in adverse growers’ reaction. To sustain farmers in the Moroccan semi-arid regions and to optimize barley production, we have focused on Net Blotch epidemiology and the development of adequate disease management approaches. A field experiment, conducted in five locations for two consecutive years, used six cultivars with different levels of susceptibility to Net Blotch. These cultivars were grown under high, medium and low inoculum levels of the pathogen, and with and without disease control. Hence, a broad range of disease epidemics was generated. All the disease progress curves showed a depression in disease severity at stem elongation. The boost in biomass production coupled with the relationship between initial disease severity and area under the disease progress curve led us to recommend seed treatment and/or seedling resistance as the initial means of disease control. Although statistical differences were measured in disease severity between fungicide treated and inoculated plots during the growing season, biological differences were not substantial until all the cultivars attained boot stage. Because of this, a single application of foliar fungicide is necessary at boot stage, with a second application needed toward the end of ear emergence when weather conditions favor disease development.
Morten Lillemo - One of the best experts on this subject based on the ideXlab platform.
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Identification of quantitative trait loci associated with resistance to Net form Net Blotch in a collection of Nordic barley germplasm
Theoretical and Applied Genetics, 2017Co-Authors: Ronja Wonneberger, Andrea Ficke, Morten LillemoAbstract:Key message Association mapping of resistance to Pyrenophora teres f. teres in a collection of Nordic barley germplasm at different developmental stages revealed 13 quantitative loci with mostly small effects . Abstract Net Blotch, caused by the necrotrophic fungus Pyrenophora teres , is one of the major diseases in barley in Norway causing quantitative and qualitative yield losses. Resistance in Norwegian cultivars and germplasm is generally insufficient and resistance sources have not been extensively explored yet. In this study, we mapped quantitative trait loci (QTL) associated with resistance to Net Blotch in Nordic germplasm. We evaluated a collection of 209 mostly Nordic spring barley lines for reactions to Net form Net Blotch (NFNB; Pyrenophora teres f. teres) in inoculations with three single conidia isolates at the seedling stage and in inoculated field trials at the adult stage in 4 years. Using 5669 SNP markers genotyped with the Illumina iSelect 9k Barley SNP Chip and a mixed linear model accounting for population structure and kinship, we found a total of 35 significant marker-trait associations for Net Blotch resistance, corresponding to 13 QTL, on all chromosomes. Out of these QTL, seven conferred resistance only in adult plants and four were only detectable in seedlings. Two QTL on chromosomes 3H and 6H were significant during both seedling inoculations and adult stage field trials. These are promising candidates for breeding programs using marker-assisted selection strategies. The results elucidate the geNetic background of NFNB resistance in Nordic germplasm and suggest that NB resistance is conferred by a number of genes each with small-to-moderate effects, making it necessary to pyramid these genes to achieve sufficient levels of resistance.
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Identification of quantitative trait loci associated with resistance to Net form Net Blotch in a collection of Nordic barley germplasm
TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik, 2017Co-Authors: Ronja Wonneberger, Andrea Ficke, Morten LillemoAbstract:Association mapping of resistance to Pyrenophora teres f. teres in a collection of Nordic barley germplasm at different developmental stages revealed 13 quantitative loci with mostly small effects. Net Blotch, caused by the necrotrophic fungus Pyrenophora teres, is one of the major diseases in barley in Norway causing quantitative and qualitative yield losses. Resistance in Norwegian cultivars and germplasm is generally insufficient and resistance sources have not been extensively explored yet. In this study, we mapped quantitative trait loci (QTL) associated with resistance to Net Blotch in Nordic germplasm. We evaluated a collection of 209 mostly Nordic spring barley lines for reactions to Net form Net Blotch (NFNB; Pyrenophora teres f. teres) in inoculations with three single conidia isolates at the seedling stage and in inoculated field trials at the adult stage in 4 years. Using 5669 SNP markers genotyped with the Illumina iSelect 9k Barley SNP Chip and a mixed linear model accounting for population structure and kinship, we found a total of 35 significant marker-trait associations for Net Blotch resistance, corresponding to 13 QTL, on all chromosomes. Out of these QTL, seven conferred resistance only in adult plants and four were only detectable in seedlings. Two QTL on chromosomes 3H and 6H were significant during both seedling inoculations and adult stage field trials. These are promising candidates for breeding programs using marker-assisted selection strategies. The results elucidate the geNetic background of NFNB resistance in Nordic germplasm and suggest that NB resistance is conferred by a number of genes each with small-to-moderate effects, making it necessary to pyramid these genes to achieve sufficient levels of resistance.
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mapping of quantitative trait loci associated with resistance to Net form Net Blotch pyrenophora teres f teres in a doubled haploid norwegian barley population
PLOS ONE, 2017Co-Authors: Ronja Wonneberger, Andrea Ficke, Morten LillemoAbstract:Barley Net Blotch caused by the necrotrophic fungus Pyrenophora teres is a major barley disease in Norway. It can cause grain shriveling and yield losses, and resistance in currently grown cultivars is insufficient. In this study, a set of 589 polymorphic SNP markers was used to map resistance loci in a population of 109 doubled haploid lines from a cross between the closely related Norwegian cultivars Arve (moderately susceptible) and Lavrans (moderately resistant). Resistance to three Net form Net Blotch (P. teres f. teres) single spore isolates was evaluated at the seedling stage in the greenhouse and at the adult plant stage under field conditions during three years. Days to heading and plant height were scored to assess their influence on disease severity. At the seedling stage, three to four quantitative trait loci (QTL) associated with resistance were found per isolate used. A major, putatively novel QTL was identified on chromosome 5H, accounting for 23-48% of the geNetic variation. Additional QTL explaining between 12 and 16.5% were found on chromosomes 4H, 5H, 6H and 7H, with the one on 6H being race-specific. The major QTL on 5H was also found in adult plants under field conditions in three years (explaining up to 55%) and the 7H QTL was found in field trials in one year. Additional adult plant resistance QTL on 3H, 6H and 7H were significant in single years. The resistance on chromosomes 3H, 5H, 6H and 7H originates from the more resistant parent Lavrans, while the resistance on 4H is conferred by Arve. The geNetic markers associated with the QTL found in this study will benefit marker-assisted selection for resistance against Net Blotch.
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QTL for Net Blotch severity in the Arve x Lavrans mapping population.
2017Co-Authors: Ronja Wonneberger, Andrea Ficke, Morten LillemoAbstract:QTL for Net Blotch severity in the Arve x Lavrans mapping population.
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Pearson correlation coefficients for Net Blotch severities, DH and PH and heritability (h2) within years.
2017Co-Authors: Ronja Wonneberger, Andrea Ficke, Morten LillemoAbstract:Pearson correlation coefficients for Net Blotch severities, DH and PH and heritability (h2) within years.
