Genetic relatedness of Verticillium dahliae isolates from cotton, tomato and watermelon plants

摘要

Verticillium dahliae is a vascular wilt pathogen of many crops worldwide. It has a wide host range and causes serious diseases in many woody and herbaceous plants. The pathogen is widely distributed in Greece and causes extensive losses on cotton, tomato and watermelon crops. All these crops are cultivated outdoors in Greece except for tomato which is cultivated in the greenhouse as well. Species of Verticillium are mainly characterized on the basis of morphology and the genetic diversity is much less studied than in other fungi. Races 1 and 2 have only been defined in the case of tomato wilt. The presence of race 2 is rare in Greece (6). Isolates of V. dahliae do not have host specificity but can attack a wide range of crop plants. Puhalla (5) proposed the use of vegetative compatibility to group isolates first in Fusarium oxysporum and then in other fungi. In an earlier study, 40 Verticillium dahliae isolates derived from different hosts in Greece were assessed through complementation tests andassigned to three vegetative compatibility groups (VCGs) (2). The purpose of this study was to assess diversity within a collection of isolates derived from diseased cotton, tomato and watermelon plants.