May
2006
, Volume
19
, Number
5
Pages
550
-
556
Authors
Brahim
Bouizgarne
,
1
,
2
,
3
Hayat
El-Maarouf-Bouteau
,
4
Karine
Madiona
,
1
Bernadette
Biligui
,
1
Michèle
Monestiez
,
1
Anne Marie
Pennarun
,
1
Zahia
Amiar
,
1
Jean Pierre
Rona
,
1
Yedir
Ouhdouch
,
3
Ismaïl
El Hadrami
,
2
and
François
Bouteau
1
Affiliations
1LEM (EA 3514), Université Paris 7, 2, place Jussieu, 750251 Paris cedex 05, France; 2Laboratoire de Physiologie Végétale, Equipe Biotechnologies et Physiologie Végétales, Faculté des Sciences-Semlalia, B.P. 2390, 40001 Marrakech, Maroc; 3Laboratoire de Microbiologie, Faculté des Sciences-Semlalia, B.P. 2390, 40001 Marrakech, Maroc; 4Laboratoire de Parasitologie Végétale, UPMC, 3, rue Galilée, 94200 Ivry sur Seine, France
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RelatedArticle
Accepted 9 January 2006.
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.
JnArticleKeywords
Additional keyword:
ion fluxes.
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ArticleCopyright
The American Phytopathological Society, 2006