ac9b01634_si_001.pdf (1.32 MB)
Combination of Isotope Labeling and Molecular Networking of Tandem Mass Spectrometry Data To Reveal 69 Unknown Metabolites Produced by Penicillium nordicum
journal contribution
posted on 2019-09-11, 18:40 authored by Thaïs Hautbergue, Emilien L. Jamin, Robin Costantino, Souria Tadrist, Lauriane Meneghetti, Jean-Claude Tabet, Laurent Debrauwer, Isabelle P. Oswald, Olivier PuelThe
secondary metabolome of Penicillium nordicum is poorly
documented despite its frequent detection on contaminated food and
its capacity to produce toxic metabolites such as ochratoxin A. To
characterize metabolites produced by this fungi, we combined a full
stable isotopes labeling with the dereplication of tandem mass spectrometry
(MS/MS) data by molecular networking. First, the untargeted metabolomic
analysis by high-resolution mass spectrometry of a double stable isotope
labeling of P. nordicum enabled the specific detection
of its metabolites and the unambiguous determination of their elemental
composition. Analyses showed that infection of substrate by P. nordicum lead to the production of at least 92 metabolites
and that 69 of them were completely unknown. Then, curated molecular
networks of MS/MS data were generated with GNPS and MetGem, specifically
on the features of interest, which allowed highlighting 13 fungisporin-related
metabolites that had not previously been identified in this fungus
and 8 that had never been observed in any fungus. The structures of
the unknown compounds, namely, a native fungisporin and seven linear
peptides, were characterized by tandem mass spectrometry experiments.
The analysis of P. nordicum growing on its natural
substrates, i.e. pork ham, turkey ham, and cheese, demonstrated that
10 of the known fungisporin-related metabolites and three of the new
metabolites were also synthesized. Thus, the curation of data for
molecular networking using a specific detection of metabolites of
interest with stable isotopes labeling allowed the discovery of new
metabolites produced by the food contaminant P. nordicum.