Vegetative Compatibility Groups of Verticillium dahliae in Israel: Their Distribution and Association with Pathogenicity

Abstract

A collection of 565 isolates of Verticillium dahliae, recovered between 1992 and 1997 from 13 host plant species and soil at 47 sites in Israel, was tested for vegetative compatibility using nitrate-nonutilizing (nit) mutants. Three vegetative compatibility groups (VCGs) were found and identified as VCG2A (28 isolates), VCG2B (158 isolates), and VCG4B (378 isolates) by using international reference strains. One isolate was heterokaryon self-incompatible. Of the VCG2B isolates, 92% were recovered from the northern part of Israel and 90% of VCG4B isolates were recovered from the south, with some overlap in the central region. Isolates of the minor group VCG2A were geographically scattered among the two major VCGs. Isolates of the same VCG resembled one another more than isolates from different VCGs based on colony and microsclerotial morphology, temperature responses, and, partially, pathogenicity. Different pathotypes were defined among 60 isolates tested, using cotton (cv. Acala SJ-2) and eggplant (cv. Black Beauty) as differentials. All isolates in VCG2A and 86% of the isolates in VCG4B, irrespective of their origin, induced weak to moderate symptoms on cotton and moderate to severe symptoms on eggplant and were similar to the previously described cotton nondefoliating patho-type. In contrast, all cotton isolates in VCG2B caused severe foliar symptoms, stunting, and often death, but little or no defoliation of inoculated cotton plants. These were defined as a cotton defoliating-like pathotype and induced only weak to moderate symptoms on eggplant. We concluded that vegetative compatibility grouping of V. dahliae in Israel is closely associated with specific pathogenicity and other phenotypic traits.

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

“…Indeed, some studies point to a worldwide, prevalent distribution of VCG1, VCG2, and VCG4, suggesting a limited VCG diversity. Other investigations suggested that some VCGs may prevail on a crop in a given geographic area (Joaquim and Rowe 1991;Strausbaugh 1993;Katan 2000b;Subbarao et al 1995;Dobinson et al 1998;Elena 2000;Korolev et al 2000;Bhat et al 2003;Hiemstra and RatajGuranowska 2003). On the other hand, considering VCGs as fully genetically isolated groups may be a strict statement.…”

Spatiotemporal Analysis of Spread of Infections by Verticillium dahliae Pathotypes Within a High Tree Density Olive Orchard in Southern Spain

“…In Spain, the D pathotype was first reported infecting cotton in a restricted area of intensive cultivation at the southern part of Andalusia in 1981 (2). This pathotype has now appeared to distant cotton-and olive-growing areas all over Andalusia (8), but has not yet been reported in other olive growing areas in northern Spain or other countries in the Mediterranean Basin, except Greece (11) and Israel (25).…”

First report of the presence of Verticillium dahliae VCG1A in Australia

“…Nit mutants were generated on water agar-chlorate (WAC) (Korolev and Katan 1997) VCG3, strain 70-21; and VCG4A, strain 131 M) and Israeli nit testers (VCG2A, strain Cot200; VCG2B, strain Ep8M, and VCG4B, strain Pt15M) (Korolev et al 2000) in all possible combinations.…”

“…Israeli nit testers of VCG2A, VCG2B, and VCG4B w e r e pr e v i o u s l y s h o w n to c o r r e l a t e w i t h t h e international OARDC reference strains (Korolev et al 2000;Korolev et al 2008;Rowe 1995). The cotton defoliating strain T9 (the original defoliating pathotype from cotton in California) belongs to subgroup VCG1A (Bell 1994).…”