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Ponts N, Pinson-Gadais L, Verdal-Bonnin MN, Barreau C,
Richard-Forget F.
Accumulation of Vomitoxin (deoxynivalenol)
(DON) and its 15-acetylated form is significantly
modulated by oxidative stress in liquid cultures of Fusarium
graminearum.
FEMS Microbiol Lett. 2006 May;258(1):102-7
INRA Centre de Bordeaux, UPR1264 MycSA, Villenave d'Ornon,
France.
Liquid cultures of Fusarium graminearum were supplemented with
H2O2 or other oxidative compounds. The accumulation kinetics of
the resulting trichothecenes were monitored. At non-lethal
concentrations, the H2O2 treatments modulated toxin
accumulation, dependent on the method of supplementation. When
H2O2 was added at the same time as the inoculation, higher
levels of toxins accumulated 30 days later. Conversely, adding
H2O2 2 or 7 days after inoculation had little effect. When H2O2
was added daily over the course of the culture, the accumulation
of trichothecenes was rapidly and strongly enhanced. The fungus
may adapt to oxidative stress when the first exposure to H2O2
occurs at the beginning of the culture course. The highest toxin
levels were measured when the H2O2 was added daily. The
importance of the first hours of culture was confirmed:
pre-treating conidia with H2O2 does not affect their germination
kinetics but leads to a reduction in the yield of trichothecenes
40 days later. The H2O2 regulation of this trichothecene
accumulation may be specific, as paraquat, another pro-oxidant
compound, inhibits their production. Since H2O2 is a major
component of the oxidative burst occurring in pathogen/host
interactions, these data support the theory that trichothecenes
may act as virulence factors.
PMID: 16630263
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