Production of Fusaric Acid by Fusarium spp. in Pure Culture and in Solid Medium Co-Cultures
Nadine Bohni,
Valérie Hofstetter,
Katia Gindro,
Bart Buyck,
Olivier Schumpp,
Samuel Bertrand,
Michel Monod,
Jean-Luc Wolfender
Affiliations
Nadine Bohni
School of Pharmaceutical Sciences, EPGL, University of Geneva, University of Lausanne, Quai Ernest-Ansermet 30, CH-1211 Geneva 4, Switzerland
Valérie Hofstetter
Mycology and Biotechnology Group, Institute for Plant Production Sciences IPS, Agroscope, Route de Duillier 50, P. O. Box 1012, CH-1260 Nyon, Switzerland
Katia Gindro
Mycology and Biotechnology Group, Institute for Plant Production Sciences IPS, Agroscope, Route de Duillier 50, P. O. Box 1012, CH-1260 Nyon, Switzerland
Bart Buyck
Muséum National d’Histoire Naturelle, Département Systématique et Évolution, CP 39, ISYEB, UMR 7205 CNRS MNHN UPMC EPHE, 12 rue Buffon, F-75005 Paris, France
Olivier Schumpp
Mycology and Biotechnology Group, Institute for Plant Production Sciences IPS, Agroscope, Route de Duillier 50, P. O. Box 1012, CH-1260 Nyon, Switzerland
Samuel Bertrand
School of Pharmaceutical Sciences, EPGL, University of Geneva, University of Lausanne, Quai Ernest-Ansermet 30, CH-1211 Geneva 4, Switzerland
Michel Monod
Department of Dermatology and Venereology, Laboratory of Mycology, Centre Hospitalier Universitaire Vaudois, CH-1011 Lausanne, Switzerland
Jean-Luc Wolfender
School of Pharmaceutical Sciences, EPGL, University of Geneva, University of Lausanne, Quai Ernest-Ansermet 30, CH-1211 Geneva 4, Switzerland
The ability of fungi isolated from nails of patients suffering from onychomycosis to induce de novo production of bioactive compounds in co-culture was examined. Comparison between the metabolite profiles produced by Sarocladium strictum, by Fusarium oxysporum, and by these two species in co-culture revealed de novo induction of fusaric acid based on HRMS. Structure confirmation of this toxin, using sensitive microflow NMR, required only three 9-cm Petri dishes of fungal culture. A targeted metabolomics study based on UHPLC-HRMS confirmed that the production of fusaric acid was strain-dependent. Furthermore, the detected toxin levels suggested that onychomycosis-associated fungal strains of the F. oxysporum and F. fujikuroi species complexes are much more frequently producing fusaric acid, and in higher amount, than strains of the F. solani species complex. Fusarium strains producing no significant amounts of this compound in pure culture, were shown to de novo produce that compound when grown in co-culture. The role of fusaric acid in fungal virulence and defense is discussed.
