Biological characterization of French Potato virus Y (PVY) isolates collected from PVY-susceptible or -resistant tobacco plants possessing the recessive resistance gene va

Authors

  • C. Lacroix,

    1. INRA-Agrocampus Ouest-Université Rennes1, UMR1099 BiO3P (Biology of Organisms and Populations applied to Plant Protection), F-35653 Le Rheu
    2. Imperial Tobacco Group, SEITA, Institut du Tabac, Domaine de la Tour, F-24100 Bergerac
    Search for more papers by this author
  • L. Glais,

    1. FNPPPT (Fédération Nationale des Producteurs de Plants de Pomme de Terre), 43-45 rue de Naples, F-75008 Paris, France
    Search for more papers by this author
  • C. Kerlan,

    1. INRA-Agrocampus Ouest-Université Rennes1, UMR1099 BiO3P (Biology of Organisms and Populations applied to Plant Protection), F-35653 Le Rheu
    Search for more papers by this author
  • J.-L. Verrier,

    1. Imperial Tobacco Group, SEITA, Institut du Tabac, Domaine de la Tour, F-24100 Bergerac
    Search for more papers by this author
  • E. Jacquot

    Corresponding author
    1. INRA-Agrocampus Ouest-Université Rennes1, UMR1099 BiO3P (Biology of Organisms and Populations applied to Plant Protection), F-35653 Le Rheu
    Search for more papers by this author

E-mail: emmanuel.jacquot@rennes.inra.fr

Abstract

Improved tobacco cultivars introgressed with alleles of the recessive resistance va gene have been widely deployed in France to limit agronomical consequences associated with Potato virus Y (PVY) infections. Unfortunately, necrotic symptoms associated with PVY have been reported on these cultivars suggesting that PVY is able to overcome the resistance. A field survey was performed in France in 2007 to (i) estimate the prevalence of PVY in tobacco plants showing symptoms and (ii) characterize PVY isolates present in susceptible and va-derived tobacco cultivars. A serological typing procedure, applied to 556 leaves collected from different French tobacco growing areas, was performed using polyclonal antisera raised against different viral species including PVY. Viral species were detected in 80·8% of leaves and PVY was present in 83·5% of infected samples. However, statistical analysis confirmed that the probability of a tobacco plant being infected with PVY is reduced in va hosts. Eighty-six PVY isolates were mechanically inoculated on one susceptible and three va-derived tobacco cultivars used as indicator hosts to define virulence of these isolates against alleles 0, 1 and 2 of the va gene. Both qualitative and quantitative analyses showed that 55 PVY isolates were able to overcome the three va alleles. Moreover, the monitored biological diversity of PVY isolates was higher in the susceptible tobacco hosts than in the va-derived ones. This study helps to understand consequences of the deployment of the va gene in tobacco on diversity and virulence of PVY isolates.

Ancillary