Verticillium wilt, caused by Verticillium dahliae, is an important disease of cotton worldwide. Isolates of V. dahliae can be characterized as race 1 or race 2 based on the responses of differential cultivars of tomato and lettuce, or as defoliating or nondefoliating based on symptom expression in cotton. To investigate the frequency and distribution of races and defoliation phenotypes of cotton-associated V. dahliae, 317 isolates from China, Israel, Turkey, and the United States were tested by polymerase chain reaction (PCR) using defoliating, nondefoliating, and race 1- and race 2-specific primers DF/DR, NDF/NDR, VdAve1F/VdAve1R, and VdR2F/VdR2R, respectively. Of the total, 97.2% of isolates genotyped as defoliating were also characterized as race 2, while 90.8% of isolates genotyped as nondefoliating were also genotyped as race 1. To verify these results, three cotton cultivars—‘FM 2484B2F’ (highly resistant), ‘98M-2983’ (highly susceptible), and ‘CA4002’ (partially resistant)—used as differentials were each inoculated with 10 isolates characterized by PCR: six defoliating/race 2 strains (GH1005, GH1021, HN, XJ2008, XJ592, and reference strain Ls17) and four nondefoliating/race 1 strains (GH1015, GH1016, GH1020, and reference strain Ls16). All defoliating/race 2 isolates except for Ls17 caused defoliation on 98M-2983 and CA4002. Isolate Ls17 caused defoliation on 98M-2983 only. The nondefoliating/race 1 isolates caused Verticillium wilt symptoms devoid of defoliation on 98M-2983. The greenhouse assays confirmed the molecular identification of race and defoliation phenotype. Although the existence of races has not been previously established among V. dahliae isolates from cotton, the long-established nondefoliating and defoliating population structure corresponded with V. dahliae races 1 and 2, respectively.
Verticillium longisporum is an economically important vascular pathogen of Brassicaceae crops in different parts of the world. V. longisporum is a diploid hybrid that consists of three different lineages, each of which originated from a separate hybridization event between two different sets of parental species. We used 20 isolates representing the three V. longisporum lineages and the relative V. dahliae, and performed pathogenicity tests on 11 different hosts, including artichoke, cabbage, cauliflower, cotton, eggplant, horseradish, lettuce, linseed, oilseed rape (canola), tomato, and watermelon. V. longisporum was overall more virulent on the Brassicaceae crops than V. dahliae, which was more virulent than V. longisporum across the non-Brassicaceae crops. There were differences in virulence between the three V. longisporum lineages. V. longisporum lineage A1/D1 was the most virulent lineage on oilseed rape, and V. longisporum lineage A1/D2 was the most virulent lineage on cabbage and horseradish. We also found that on the non-Brassicaceae hosts eggplant, tomato, lettuce, and watermelon, V. longisporum was more or equally virulent than V. dahliae. This suggests that V. longisporum may have a wider potential host range than currently appreciated.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.