EVIDENCE FOR A FORMA SPECIALIS SPECIFIC EFFECT OF ANTIFUNGAL FLAVONOLS IN FUSARIUM OXYSPORUM

Previous experiments evidenced that three natural flavonols, extracted from carnation (Dianthus caryophyllus), are provided with an antifungal activity towards the forma specialis “dianthi” of the pathogenic fungal species Fusarium oxysporum. In the present research, the same three molecules have been assayed against further four formae speciales of Fusarium oxysporum affecting ornamental plants: f. sp. asparagi, f. sp. ranunculi, f. sp. cyclaminis and f. sp. lilii. The compound effect was evaluated as ability of inhibiting mycelial growth and spore germination.
Among the assayed flavonol aglycones, the 4’-methoxylated flavonol kaempferide was particularly effective, and generally speaking the glycosylated forms were more active than the corresponding aglycones.
The inhibiting effect of a same flavonol proved to vary depending on the different fungal forma specialis, therefore indicating that fungal tolerance towards fungitoxic flavonoids could be genotype-dependent.
This also means that flavonols fungitoxic to Fusarium oxysporum exert an effect which is strictly specific for each forma specialis. Further studies should be aimed to assess if this tolerance mechanism is nondegradative or relies instead on the antifungal compound metabolization.

XXII International Eucarpia Symposium, Section Ornamentals, Breeding for Beauty – Part II

F. Galeotti, V. Lanzotti, F. D’Aquila, M. Amoretti, P. Curir

polyphenols, specificity, fungitoxic molecules, Fusarium wilt, genotypes

https://doi.org/10.17660/ActaHortic.2007.743.16