Abstract :
[en] Aspergillus flavus is a phytopathogenic fungus able to produce aflatoxin B1 (AFB1), a carcinogenic mycotoxin that can contaminate several crops and food commodities. In A. flavus, two
different kinds of strains can co-exist: toxigenic and non-toxigenic strains. Microbial-derived volatile
organic compounds (mVOCs) emitted by toxigenic and non-toxigenic strains of A. flavus were analyzed by solid phase microextraction (SPME) coupled with gas chromatography–mass spectrometry (GC-MS) in a time-lapse experiment after inoculation. Among the 84 mVOCs emitted, 44 were
previously listed in the scientific literature as specific to A. flavus, namely alcohols (2-methylbutan1-ol, 3-methylbutan-1-ol, 2-methylpropan-1-ol), aldehydes (2-methylbutanal, 3-methylbutanal), hydrocarbons (toluene, styrene), furans (2,5-dimethylfuran), esters (ethyl 2-methylpropanoate, ethyl
2-methylbutyrate), and terpenes (epizonaren, trans-caryophyllene, valencene, α-copaene, β-himachalene, γ-cadinene, γ-muurolene, δ-cadinene). For the first time, other identified volatile compounds such as α-cadinol, cis-muurola-3,5-diene, α-isocomene, and β-selinene were identified as
new mVOCs specific to the toxigenic A. flavus strain. Partial Least Square Analysis (PLSDA) showed
a distinct pattern between mVOCs emitted by toxigenic and non-toxigenic A. flavus strains, mostly
linked to the diversity of terpenes emitted by the toxigenic strains. In addition, the comparison between mVOCs of the toxigenic strain and its non-AFB1-producing mutant, coupled with a semiquantification of the mVOCs, revealed a relationship between emitted terpenes (β-chamigrene, αcorocalene) and AFB1 production. This study provides evidence for the first time of mVOCs being
linked to the toxigenic character of A. flavus strains, as well as terpenes being able to be correlated
to the production of AFB1 due to the study of the mutant. This study could lead to the development
of new techniques for the early detection and identification of toxigenic fungi.
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