Host resistances to Aphanomyces trifolii root rot of subterranean clover: first opportunity to successfully manage this severe pasture disease

Mingpei You, T.A. O'Rourke, K. Foster, R. Snowball, Martin Barbetti

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    5 Citations (Scopus)

    Abstract

    © 2015 British Society for Plant PathologySubterranean clover (Trifolium subterraneum) is an important pasture legume in Australia (29 million ha) and elsewhere. However, severe pasture decline occurs in association with several root pathogens, including Aphanomyces trifolii, that has been misidentified for decades as A. euteiches until recently confirmed as A. trifolii. A series of controlled environment experiments was undertaken to identify host resistance to A. trifolii in subterranean clover and to compare virulence and phylogeny of isolates. In experiment 1, Dalkeith, Bacchus Marsh, Riverina and Yarloop were the most resistant of 38 cultivars with a percentage disease index (PDI) ≤10 for both tap and lateral roots. Experiment 2 confirmed resistance of Yarloop, but a change in some relative varietal resistances suggested physiological specialization among A. trifolii isolates. Experiment 3 confirmed extensive variation in virulence and physiological specialization across 23 isolates of A. trifolii, with three distinct clades, two of which were distinct from isolates collected previously. Experiment 4 identified host resistance(s) effective against a mixture of 20 A. trifolii isolates, but the most resistant cultivars (Antas, Uniwager, Leura) still showed significant disease. This is the first study to show physiological specialization in A. trifolii and to identify host resistance. This study defines A. trifolii as a significant but largely unknown contributor to severe root disease of subterranean clover in southern Australia. Finally, development and calibration of a new soil commercial DNA test not only enables field quantification of the disease, but development of appropriate breeding, selection and farm management strategies to reduce its impact.
    Original languageEnglish
    Pages (from-to)901-913
    JournalPlant Pathology
    Volume65
    Issue number6
    DOIs
    Publication statusPublished - 2016

    Fingerprint

    Aphanomyces
    Medicago
    Trifolium subterraneum
    root rot
    pastures
    virulence
    Aphanomyces euteiches
    varietal resistance
    Virulence
    root diseases
    farm management
    forage legumes
    cultivars
    Trifolium
    Controlled Environment
    marshes
    Wetlands
    calibration
    Phylogeny
    Fabaceae

    Cite this

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    title = "Host resistances to Aphanomyces trifolii root rot of subterranean clover: first opportunity to successfully manage this severe pasture disease",
    abstract = "{\circledC} 2015 British Society for Plant PathologySubterranean clover (Trifolium subterraneum) is an important pasture legume in Australia (29 million ha) and elsewhere. However, severe pasture decline occurs in association with several root pathogens, including Aphanomyces trifolii, that has been misidentified for decades as A. euteiches until recently confirmed as A. trifolii. A series of controlled environment experiments was undertaken to identify host resistance to A. trifolii in subterranean clover and to compare virulence and phylogeny of isolates. In experiment 1, Dalkeith, Bacchus Marsh, Riverina and Yarloop were the most resistant of 38 cultivars with a percentage disease index (PDI) ≤10 for both tap and lateral roots. Experiment 2 confirmed resistance of Yarloop, but a change in some relative varietal resistances suggested physiological specialization among A. trifolii isolates. Experiment 3 confirmed extensive variation in virulence and physiological specialization across 23 isolates of A. trifolii, with three distinct clades, two of which were distinct from isolates collected previously. Experiment 4 identified host resistance(s) effective against a mixture of 20 A. trifolii isolates, but the most resistant cultivars (Antas, Uniwager, Leura) still showed significant disease. This is the first study to show physiological specialization in A. trifolii and to identify host resistance. This study defines A. trifolii as a significant but largely unknown contributor to severe root disease of subterranean clover in southern Australia. Finally, development and calibration of a new soil commercial DNA test not only enables field quantification of the disease, but development of appropriate breeding, selection and farm management strategies to reduce its impact.",
    author = "Mingpei You and T.A. O'Rourke and K. Foster and R. Snowball and Martin Barbetti",
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    TY - JOUR

    T1 - Host resistances to Aphanomyces trifolii root rot of subterranean clover: first opportunity to successfully manage this severe pasture disease

    AU - You, Mingpei

    AU - O'Rourke, T.A.

    AU - Foster, K.

    AU - Snowball, R.

    AU - Barbetti, Martin

    PY - 2016

    Y1 - 2016

    N2 - © 2015 British Society for Plant PathologySubterranean clover (Trifolium subterraneum) is an important pasture legume in Australia (29 million ha) and elsewhere. However, severe pasture decline occurs in association with several root pathogens, including Aphanomyces trifolii, that has been misidentified for decades as A. euteiches until recently confirmed as A. trifolii. A series of controlled environment experiments was undertaken to identify host resistance to A. trifolii in subterranean clover and to compare virulence and phylogeny of isolates. In experiment 1, Dalkeith, Bacchus Marsh, Riverina and Yarloop were the most resistant of 38 cultivars with a percentage disease index (PDI) ≤10 for both tap and lateral roots. Experiment 2 confirmed resistance of Yarloop, but a change in some relative varietal resistances suggested physiological specialization among A. trifolii isolates. Experiment 3 confirmed extensive variation in virulence and physiological specialization across 23 isolates of A. trifolii, with three distinct clades, two of which were distinct from isolates collected previously. Experiment 4 identified host resistance(s) effective against a mixture of 20 A. trifolii isolates, but the most resistant cultivars (Antas, Uniwager, Leura) still showed significant disease. This is the first study to show physiological specialization in A. trifolii and to identify host resistance. This study defines A. trifolii as a significant but largely unknown contributor to severe root disease of subterranean clover in southern Australia. Finally, development and calibration of a new soil commercial DNA test not only enables field quantification of the disease, but development of appropriate breeding, selection and farm management strategies to reduce its impact.

    AB - © 2015 British Society for Plant PathologySubterranean clover (Trifolium subterraneum) is an important pasture legume in Australia (29 million ha) and elsewhere. However, severe pasture decline occurs in association with several root pathogens, including Aphanomyces trifolii, that has been misidentified for decades as A. euteiches until recently confirmed as A. trifolii. A series of controlled environment experiments was undertaken to identify host resistance to A. trifolii in subterranean clover and to compare virulence and phylogeny of isolates. In experiment 1, Dalkeith, Bacchus Marsh, Riverina and Yarloop were the most resistant of 38 cultivars with a percentage disease index (PDI) ≤10 for both tap and lateral roots. Experiment 2 confirmed resistance of Yarloop, but a change in some relative varietal resistances suggested physiological specialization among A. trifolii isolates. Experiment 3 confirmed extensive variation in virulence and physiological specialization across 23 isolates of A. trifolii, with three distinct clades, two of which were distinct from isolates collected previously. Experiment 4 identified host resistance(s) effective against a mixture of 20 A. trifolii isolates, but the most resistant cultivars (Antas, Uniwager, Leura) still showed significant disease. This is the first study to show physiological specialization in A. trifolii and to identify host resistance. This study defines A. trifolii as a significant but largely unknown contributor to severe root disease of subterranean clover in southern Australia. Finally, development and calibration of a new soil commercial DNA test not only enables field quantification of the disease, but development of appropriate breeding, selection and farm management strategies to reduce its impact.

    U2 - 10.1111/ppa.12475

    DO - 10.1111/ppa.12475

    M3 - Article

    VL - 65

    SP - 901

    EP - 913

    JO - Plant Pathology

    JF - Plant Pathology

    SN - 0032-0862

    IS - 6

    ER -