title: A putative role for fusaric acid in biocontrol of the parasitic angiosperm Orobanche ramosa.
abstract: Fusarium spp. are ubiquitous fungi found in soil worldwide as both pathogenic and nonpathogenic strains. The signals leading to disease or the absence of disease are poorly understood. We recently showed that fusaric acid (FA), a nonspecific toxin produced by most Fusarium spp., could elicit various plant defense responses at 100 nM without toxic effect. In this study, we checked for the effect of FA on root and root hairs, probable first site of contact between the fungi and the host. Large FA concentrations reduce root and root-hair growth and induce a rapid transient membrane hyperpolarization, followed by a large depolarization, due to the inhibition of H(+)-ATPase currents. Nanomolar concentrations of FA induced only an early transient membrane hyperpolarization of root hairs compatible with the induction of a signal transduction pathway. FA at 10(-7) M failed to induce salicylic acid- and jasmonic acid/ethylene-dependent defense-related genes but inhibited the germination of the angiosperm parasite Orobanche ramosa in contact of FA-pretreated Arabidopsis thaliana seedlings. These data suggest that FA at nontoxic concentrations could activate signal transduction components necessary for plant-defense responses that could contribute to biocontrol activity of Fusarium spp.
authors: LEM (EA 3514), Université Paris 7, 2, place Jussieu, 750251 Paris 05, France.
authors: Brahim
authors: B
authors: Bouizgarne
authors: Hayat
authors: H
authors: El-Maarouf-Bouteau
authors: Karine
authors: K
authors: Madiona
authors: Bernadette
authors: B
authors: Biligui
authors: Michèle
authors: M
authors: Monestiez
authors: Anne Marie
authors: AM
authors: Pennarun
authors: Zahia
authors: Z
authors: Amiar
authors: Jean Pierre
authors: JP
authors: Rona
authors: Yedir
authors: Y
authors: Ouhdouch
authors: Ismaïl
authors: I
authors: El Hadrami
authors: François
authors: F
authors: Bouteau