Reassessment of Vegetative Compatibility Relationships Among Strains ofVerticillium dahliaeUsing Nitrate-Nonutilizing Mutants

Verticillium wilt of olive: a case study to implement an integrated strategy to control a soil-borne pathogen

“…However, a clear-cut association between isolates of a particular VCG and their pathogenicity or virulence in a given host plant is not always easy to ascertain. Thus, some studies support the correlation between VCG assignment of isolates and their differential virulence displayed in a given plant (Joaquim and Rowe 1990;Bhat and Subbarao 1999;Tsror et al 2001;Korolev et al 2001), whereas others conclude that different isolates from the same VCG show different degrees of virulence in a same crop (Elena 1999;Korolev et al 2000Korolev et al , 2001. Interesting examples pointing to an association between genetic groups and host specificity are: i) the predominance of isolates assigned to VCG4 in potato (Solanum tuberosum L.) infections in the United States and Israel (Joaquim and Rowe 1991;Strausbaugh et al 1992;Korolev et al 2000); ii) the aforementioned association of the highly-virulent, D-pathotype isolates of cotton (Gossypium hirsutum L.) with their assignment to VCG1A described in various areas such as Central Asia, China, Israel, Peru, Spain, Turkey and USA (Daayf et al 1995;Korolev et al 2001;Zhengjun et al 1998;Korolev et al 2008;Dervis et al 2008), in what may constitute an example of dispersal of isolates from an original focus of infected cotton genotypes; or iii) the prevalence of VCG2A and 2B isolates infecting artichoke (Cynara scolymus L.) in a defined artichokecultivating region of eastern-central Spain, with VCG2B being the most virulent in this host .…”

“…On the other hand, considering VCGs as fully genetically isolated groups may be a strict statement. In fact, the existence of weak complementation and formation of heterokaryons between isolates belonging to different VCGs (or certain subgroups), or even between different Verticillium species, has been described (Daayf et al 1995;Hiemstra and Rataj-Guranowska 2003;Joaquim and Rowe 1990;Strausbaugh et al 1992). This may suggest the existence of a continuum of genetic variation surpassing the genetic barrier of the VCG.…”

“…The differentiation into subgroups A and B is based on the frequency and vigor of nit mutant complementation (Joaquim and Rowe 1991;Strausbaugh 1993). Other VCGs, either less prevalent or localized in well-defined geographical areas, have been reported as well (namely VCG3, VCG5, VCG6, VCGBr or VCGBa) (Bhat and Subbarao 1999;Bhat et al 2003;Joaquim and Rowe 1990;Strausbaugh et al 1992;Jiménez-Díaz et al 2006). Regarding to V. dahliae isolates infecting olive, only representatives of VCG1A, VCG2A, VCG2B, and VCG4B have so far been identified (Pérez-Artés et al 2000;Cherrab et al 2002;Tantaoui et al 2002;Tsror and Levin 2003;Bellahcene et al 2005b;Sanei et al 2005;Collado-Romero et al 2006;Dervis et al 2007Dervis et al , 2010 (Fig.…”

Determination of the Response of Some Cotton Varieties to Cotton Wilt Disease Caused by Verticillium dahliae Kleb

“…One of these factors is the Verticillium wilt caused by Verticillium dahliae Kleb. The pathogen may cause wilt in more than 400 plant species with a series of host plants like vegetables, ornamental plants, legumes, industrial plants, fruit trees and weeds (Joaquim and Rowe, 1990).…”

Difficulty to establish vegetative compatibility of Japanese isolates of Verticillium dahliae Kleb. using melanin-synthesis deficient mutants.

“…Recently, pathotypes of V. dahliae previously designated as VCGs using microsclerotial color mutants were reassessed using nitrate non-utilizing (nit) mutants. It was reported that many pathotypes were found to be compatible using nit mutants (19,20,32).…”