Plant Disease (2015) 99, 1713-1720

Xiao-Ping Hu, Suraj Gurung, Dylan P.G. Short, German V. Sandoya, Wen-Jing Shang, Ryan J. Hayes, R. Michael Davis and Krishna V. Subbarao (2015)
Nondefoliating and defoliating strains from cotton correlate with races 1 and 2 of Verticillium dahliae
Plant Disease 99 (12), 1713-1720
Abstract: 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.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Krishna V. Subbarao, Xiaoping Hu, R. Michael Davis, Germán V. Sandoya

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Verticillium dahliae	Cotton (Gossypium)	Turkey
	Verticillium dahliae	Cotton (Gossypium)	Israel