Genetic diversity and host range of verticillium dahliae isolates from artichoke and other vegetable crops in Spain

Artichoke is severely affected by Verticillium wilt, caused by Verticillium dahliae, in easterncentral Spain, which is one of the most important vegetable-cropping areas in the country. To determine genetic and virulence variability in local populations of V. dahliae, 18 isolates collected from artichoke and other vegetable species cultivated in eastern-central Spain were selected to represent local vegetative compatibility groups (VCGs). Diversity in the isolates was characterized by molecular markers and virulence in 12 important hosts for that region. Recently developed microsatellite markers (simple-sequence repeats) and polymorphic sequences were used to assess the genetic variation among those isolates to reveal any association occurring among host source, VCG, and virulence. Although all isolates caused severe disease symptoms on artichoke, cardoon, eggplant, and watermelon, those from artichoke had a limited host range and isolates from watermelon, muskmelon, and eggplant were not pathogenic to some of the hosts tested. VCG diversity was related to differential virulence in certain hosts.