Phytoparasitica (2000) 28, 280-281
Nadia Korolev, J. Katan and Talma Katan (2000)
Genetic variation and virulence of Verticillium dahliae from different hosts in Israel
Phytoparasitica 28 (3), 280-281
21st Congress of the Israeli Phytopathological Society, February 14-15, 2000, Bet Dagan, Israel, poster
Abstract: A total of 742 isolates of Verticillium dahliae were recovered from 15 host plant species (chrysanthemum, cotton, eggplant, olive, peanut, pepper, potato, tomato, rose, watermelon, and five weed species) and soil, from 73 locations throughout Israel. Isolates were assigned to genetically isolated groups (vegetative compatibility groups - VCGs) by complementation tests between nit mutants using Israeli and international tester strains. Four VCGs (1, 2A, 2B, and 4B) were identified and correlated with host and geographical origin. VCG1 (37 isolates) originated from cotton from the north-eastern region of Israel; VCG2B (252 isolates) was recovered mainly from cotton in the northern part of the country, while some strains were isolated from chrysanthemum, eggplant, olive, pepper and tomato. VCG4B (414 isolates) was widespread over the Negev and was recovered from 14 host plant species (with most isolates from potato). The minor VCG2A (39 isolates) was scattered throughout the country and was often recovered from tomato, olives and eggplant. Seventy-three isolates originating from different VCGs, hosts and locations were tested for pathogenicity to cotton, eggplant and okra using the root-dip method. Three pathotypes were defined according to pathogenicity of isolates to cotton ('Acala SJ2'): defoliating (D), defoliating-like (DL), and non-defoliating (ND). D-pathotype was represented by VCG1 cotton isolates; DL-pathotype was represented mainly by VCG2B cotton isolates from the Yizre'el Valley; ND-pathotype (mostly VCGs 4B and 2A) was recovered from 15 species and was common mainly in potato fields in the Negev. Using eggplant as the second test-plant enabled us to sub-divide DL and ND pathotypes into subpathotypes (DL1, DL2, ND1, ND2 and ND3). Okra was extremely susceptible to all pathotypes, with slightly greater susceptibility to D as compared with DL and ND pathotypes. The local populations of V. dahliae associated with major crops such as cotton or potato were homogeneous for their VCG and pathotype composition (except a new focus of Verticillium wilt in the Hula Valley, where both VCGs 1 and 2B were found), whereas strains from other hosts often represented mixed populations or varied from site to site in the same region.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Jaacov Katan, Nadia Korolev
Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution
