EFS12- Book of abstracts - Contact

SESSION 2: SECONDARY METABOLITES – BIOCHEMISTRY,
BIOSYNTHESIS, FEED AND FOOD SAFETY
P14 - Metabolomics of growth and type B
trichothecenes production in Fusarium graminearum
L. Legoahec 1 , V. Atanasova-Penichon 1 , N. Ponts 1 , C. Deborde 2,3 , M.
Maucourt 3,4 , S. Bernillon 2,3 , A. Moing 2,3 , F. Richard-Forget 1
1 INRA, UR1264 MycSA, 71 avenue Edouard Bourlaux, CS20032, F-33882 Villenave d’Ornon cedex,
France; 2 INRA, UMR1332 Fruit Biology and Pathology, 71 avenue Edouard Bourlaux, CS20032, F-
33882 Villenave d’Ornon cedex, France; 3 Metabolome Facility of Bordeaux Functional Genomics
Center, IBVM Centre INRA de Bordeaux, F-33882 Villenave d'Ornon cedex, France; 4 Univ. Bordeaux,
UMR1332 Fruit Biology and Pathology, Centre INRA de Bordeaux, F-33882 Villenave d'Ornon, France
E-mail: fforget@bordeaux.inra.fr
The plant fungal pathogen Fusarium graminearum can produce type B
trichothecenes, a family of sesquiterpene molecules with toxic properties upon
human or animal ingestion. Deoxynivalenol, or DON, and its acetylated forms
belong to this family of secondary metabolites and are frequent contaminants of
cereals worldwide.
The biosynthesis of trichothecenes initiates with the condensation of two
molecules of farnesyl pyrophosphate, at the end of the mevalonate pathway in
Fusarium, and is under the control of various factors such as the redox
parameters of the environment or the carbon source. For example, supplementing
liquid submerged cultures of F. graminearum with caffeic acid, a phenolic acid
with known antioxidant properties, reduces the accumulation of DON and its
acetylated forms in the medium. Such a result, however, gives a partial glimpse of
the effect of phenolic acids, from the trichothecene production point of view only.
The present study analyzes F. graminearum metabolome in conditions when
DON and its acetylated forms are produced. Liquid chromatography coupled with
mass spectrometry and proton nuclear magnetic resonance were used to
characterize the metabolites produced by the fungus, secreted in the culture
medium or not, over the course of 14 days. Fifty-two polar and semi-polar
metabolites were identified in the culture medium, i.e., the exo-metabolites, and/or
in the mycelium, i.e., the endo-metabolites, comprising amino acids and
derivatives, sugars, polyketides, and terpenes including trichothecenes and DON
precursors. Sample composition varied over time in terms of primary metabolites
as well as secondary metabolites. Data analysis further revealed correlations,
positive or negative, between metabolic pathways. In the presence of caffeic acid,
metabolomic profiles were modified, counting those resulting from primary
metabolism even though fungal biomass production was not affected by the
treatment. Several metabolites affected by the treatment were identified for both
the exo- and endo-metabolome, in particular DON and its precursors. For the first
time, these results expose a unique outlook of a hidden aspect of Fusarium’s
response to antioxidant treatment.
Keywords: metabolomics, secondary metabolite, Fusarium graminearum
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