Molecular Phylogenetic, Morphological, and Mycotoxin Data Support Reidentification of the Quorn Mycoprotein Fungus asFusarium venenatum

Abstract

Molecular phylogenetic, morphological, and mycotoxin data were obtained in order to investigate the relationships and identity of the Quorn mycoprotein fungus withinFusariumand to examine Quorn strains and commercial Quorn food products for trichothecene mycotoxins. Phylogenetic analyses of aligned DNA sequences obtained via the polymerase chain reaction from the nuclear 28S ribosomal DNA, nuclear ribosomal internal transcribed spacer region, and β-tubulin gene exons and introns indicate that the Quorn fungus isFusarium venenatum,rather thanF. graminearumas previously reported. All of the Quorn strains examined were morphologically degenerate aconidial colonial mutants except for NRRL 25139, which produced chlamydospores in recurved terminal chains together with mostly 5-septate sporodochial conidia on doliform monophialides diagnostic ofF. venenatum.Bootstrap and decay analyses provide strong support for a monophyletic lineage containingF. venenatumand several other type A trichothecene-producing species, while reference strains ofF. graminearumwere nested in a separate clade of species that produce type B trichothecenes and/or zearalenone. Analysis of mycotoxins from rice cultures inoculated with Quorn strain NRRL 25416 revealed that four type A trichothecenes are produced, but at low levels relative to strain NRRL 22198 ofF. venenatum.No trichothecene mycotoxins, however, were detected from the analysis of three commercial Quorn products marketed for human consumption in England.