Pathogenicity, vegetative compatibility and amplified fragment length polymorphism (AFLP) analysis of Fusarium oxysporum f. sp. radicis-cucumerinum isolates from Turkish greenhouses

Abstract

The objective of the current study was to characterize Fusarium oxysporum f. sp. radiciscucumerinum isolates from cucumbers in Turkey in terms of pathogenicity, vegetative compatibility and amplified fragment length polymorphism (AFLP) variation. In the 2007 and 2008 greenhouse cucumber-growing seasons, surveys were conducted in Adana, Antalya, Hatay and Mersin provinces of the Mediterranean region of Turkey. Forty-seven fungal isolates of F. oxysporum were recovered from diseased cucumber plants. The pathogenicity of each isolate was tested on cucumber seedlings at the onetrue-leaf stage. Forty of the 47 isolates of F. oxysporum were virulent on cucumber seedlings. Based on disease symptoms, the differential effect of temperatures of 17°C and 29°C on disease development, and the virulence on cucumber seedlings, these 40 isolates were identified as F. oxysporum f. sp. radicis-cucumerinum. Nitrate non-utilizing mutants were generated on minimal medium containing 1.5% KClO 3 and their phenotypes were determined. Mutants in different phenotypic classes were paired on minimal medium; of 40 F. oxysporum f. sp. radicis-cucumerinum isolates, thirty-eight were placed into VCG 0260.Remaining two strains were assigned to VCG 0261. The AFLP primers produced a total of 180 fragments between 200 and 500 bp in length for the 30 isolates tested. At a genetic similarity of 0.71, the UPGMA analysis separated the isolates into two distinct clusters. The first cluster, AFLP I, included 28 isolates, of which all belonged to VCG 0260. Two strains in the second AFLP cluster both belonged to VCG 0261.

A mobile pathogenicity chromosome in Fusarium oxysporum for infection of multiple cucurbit species

“…However, this phenotype could only be observed at relatively high ambient temperatures (25 °C) in cucumber, while at lower temperatures all plants died. In contrast to most wilt-causing Fo pathogens like Fol, Foc, Fom and Fon, Forc symptoms develop most efficiently at temperatures below 20 °C 6 , 39 , 40 , particularly during seedling infection, when plants may be under physiological stress 6 . We conclude that Six6 contributes to virulence only under non-optimal conditions and only in cucumber.…”

Serial passage through resistant and susceptible cucumber cultivars affects the virulence of Fusarium oxysporum f. sp. cucumerinum

“…The experiment was conducted three times. The disease index (DI) of Fusarium wilt was assessed 14 days after inoculation using a 5‐grade criterion (Tok & Kurt, ; Vakalounakis et al., ) with a few modifications: 0 = no symptoms; 1 = slight to moderate rot on taproots and slight wilt on cotyledons; 2 = slight vascular discoloration in stems and one cotyledon chlorisis; 3 = slight vascular discoloration in stems and two cotyledons chlorisis; 4 = severe rot on roots, vascular discoloration, and wilt of whole plant; 5 = dead seedling.…”

Pathogenicity and Genetic Diversity of Fusarium oxysporum Causing Soybean Root Rot in Northeast China

“…momordicae isolates (Chen et al, 2014) or vegetative compatibility group of F. oxysporum f. sp. radicis-cucumerinum isolates (Tok & Kurt, 2010). AFLP was used in this study to access genetic diversity of F. oxysporum isolates in major soybean producing regions in Heilongjiang.…”

“…In another study on F. oxysporum f. sp. radicis-cucumerinum from cucumbers, analysis with AFLP markers divided the 30 isolates in two distinct clusters (Tok & Kurt, 2010). All isolates in one cluster belonged to a vegetative compatibility group and isolates in the other cluster belonged to another vegetative compatibility group.…”