Differential selection pressures exerted by host resistance quantitative trait loci on a pathogen population: a case study in an apple × Venturia inaequalis pathosystem

Authors

  • Amandine Lê Van,

    1. INRA, UMR1345 Institut de Recherche en Horticulture et Semences – IRHS, SFR 4207 QUASAV, PRES L'UNAM, Beaucouzé Cedex, France
    2. AgroCampus-Ouest, UMR1345 Institut de Recherche en Horticulture et Semences – IRHS, Angers, France
    3. Université d'Angers, UMR1345 Institut de Recherche en Horticulture et Semences – IRHS, Angers, France
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  • Valérie Caffier,

    1. INRA, UMR1345 Institut de Recherche en Horticulture et Semences – IRHS, SFR 4207 QUASAV, PRES L'UNAM, Beaucouzé Cedex, France
    2. AgroCampus-Ouest, UMR1345 Institut de Recherche en Horticulture et Semences – IRHS, Angers, France
    3. Université d'Angers, UMR1345 Institut de Recherche en Horticulture et Semences – IRHS, Angers, France
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  • Pauline Lasserre-Zuber,

    1. INRA, UMR1345 Institut de Recherche en Horticulture et Semences – IRHS, SFR 4207 QUASAV, PRES L'UNAM, Beaucouzé Cedex, France
    2. AgroCampus-Ouest, UMR1345 Institut de Recherche en Horticulture et Semences – IRHS, Angers, France
    3. Université d'Angers, UMR1345 Institut de Recherche en Horticulture et Semences – IRHS, Angers, France
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  • Aurélie Chauveau,

    1. INRA, US1279 Etude du Polymorphisme des Génomes Végétaux – EPGV, Centre National de Génotypage, Évry Cedex, France
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  • Dominique Brunel,

    1. INRA, US1279 Etude du Polymorphisme des Génomes Végétaux – EPGV, Centre National de Génotypage, Évry Cedex, France
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  • Bruno Le Cam,

    1. INRA, UMR1345 Institut de Recherche en Horticulture et Semences – IRHS, SFR 4207 QUASAV, PRES L'UNAM, Beaucouzé Cedex, France
    2. AgroCampus-Ouest, UMR1345 Institut de Recherche en Horticulture et Semences – IRHS, Angers, France
    3. Université d'Angers, UMR1345 Institut de Recherche en Horticulture et Semences – IRHS, Angers, France
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  • Charles-Eric Durel

    Corresponding author
    1. AgroCampus-Ouest, UMR1345 Institut de Recherche en Horticulture et Semences – IRHS, Angers, France
    2. Université d'Angers, UMR1345 Institut de Recherche en Horticulture et Semences – IRHS, Angers, France
    • INRA, UMR1345 Institut de Recherche en Horticulture et Semences – IRHS, SFR 4207 QUASAV, PRES L'UNAM, Beaucouzé Cedex, France
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Author for correspondence:

Charles-Eric Durel

Tel: +33 241 22 57 59

Email: charles-eric.durel@angers.inra.fr

Summary

  • Understanding how pathogens evolve according to pressures exerted by their plant hosts is essential for the derivation of strategies aimed at the durable management of resistant cultivars. The spectrum of action of the resistance factors in the partially resistant cultivars is thought to be an important determinant of resistance durability. However, it has not yet been demonstrated whether the pressures exerted by quantitative resistance are different according to their spectrum of action.
  • To investigate selection pressures exerted by apple genotypes harbouring various resistance quantitative trait loci (QTLs) on a mixed inoculum of the scab disease agent, Venturia inaequalis, we monitored V. inaequalis isolate proportions on diseased apple leaves of an F1 progeny using quantitative pyrosequencing technology and QTL mapping.
  • Broad-spectrum resistances did not exert any differential selection pressures on the mixed inoculum, whereas narrow-spectrum resistances decreased the frequencies of some isolates in the mixture relative to the susceptible host genotypes.
  • Our results suggest that the management of resistant cultivars should be different according to the spectrum of action of their resistance factors. The pyramiding of broad-spectrum factors or the use of a mixture of apple genotypes that carry narrow-spectrum resistance factors are two possible strategies for the minimization of resistance erosion.

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