title: Tracking changes in life-history traits related to unnecessary virulence in a plant-parasitic nematode.
abstract: Evaluating trade-offs in life-history traits of plant pathogens is essential to understand the evolution and epidemiology of diseases. In particular, virulence costs when the corresponding host resistance gene is lacking play a major role in the adaptive biology of pathogens and contribute to the maintenance of their genetic diversity. Here, we investigated whether life-history traits directly linked to the establishment of plant-nematode interactions, that is, ability to locate and move toward the roots of the host plant, and to invade roots and develop into mature females, are affected in Meloidogyne incognita lines virulent against the tomato Mi-1.2 resistance gene. Virulent and avirulent near-isogenic lines only differing in their capacity to reproduce or not on resistant tomatoes were compared in single inoculation or pairwise competition experiments. Data highlighted (1) a global lack of trade-off in traits associated with unnecessary virulence with respect to the nematode ability to successfully infest plant roots and (2) variability in these traits when the genetic background of the nematode is considered irrespective of its (a)virulence status. These data suggest that the variation detected here is independent from the adaptation of M. incognita to host resistance, but rather reflects some genetic polymorphism in this asexual organism.
authors.affiliation: UMR1355 Institut Sophia Agrobiotech, INRA 06900, Sophia Antipolis, France ; UMR7254 Institut Sophia Agrobiotech, University of Nice Sophia Antipolis 06900, Sophia Antipolis, France ; UMR7254 Institut Sophia Agrobiotech, CNRS 06900, Sophia Antipolis, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Castagnone-Sereno
authors.affiliation: UMR1355 Institut Sophia Agrobiotech, INRA 06900, Sophia Antipolis, France ; UMR7254 Institut Sophia Agrobiotech, University of Nice Sophia Antipolis 06900, Sophia Antipolis, France ; UMR7254 Institut Sophia Agrobiotech, CNRS 06900, Sophia Antipolis, France.
authors.forename: Karine
authors.initials: K
authors.lastname: Mulet
authors.affiliation: UMR1355 Institut Sophia Agrobiotech, INRA 06900, Sophia Antipolis, France ; UMR7254 Institut Sophia Agrobiotech, University of Nice Sophia Antipolis 06900, Sophia Antipolis, France ; UMR7254 Institut Sophia Agrobiotech, CNRS 06900, Sophia Antipolis, France.
authors.forename: Cathy
authors.initials: C
authors.lastname: Iachia
keywords: Asexual reproduction; Meloidogyne incognita; competition; cost of virulence; plant–nematode interaction