Different metabolite profiles across Penicillium roqueforti populations associated with ecological niche specialisation and domestication.

Abstract

Fungi are known to produce many chemically diversified metabolites, yet their ecological roles are not always fully understood. The blue cheese fungus Penicillium roqueforti thrives in different ecological niches and is known to produce a wide range of metabolites, including mycotoxins. Three P. roqueforti populations have been domesticated for cheese production and two populations thrive in other anthropized environments, i.e., food, lumber and silage. In this study, we looked for differences in targeted and untargeted metabolite production profiles between populations using HPLC-HR-Q-TOF and UHPLC-Q-TOF-HR-MS/MS. The non-cheese populations produced several fatty acids and different terpenoids, lacking in cheese strains. The Termignon cheese population displayed intermediate metabolite profiles between cheese and non-cheese populations, as previously shown for other traits. The non-Roquefort cheese population with the strongest domestication syndrome, produced the lowest quantities of measured metabolites, including mycophenolic acid (MPA), andrastin A and PR toxin. Its inability to produce MPA was due to a deletion in the mpaC gene, while a premature stop codon in ORF 11 of the PR toxin gene cluster explained PR toxin absence and the accumulation of its intermediates, i.e., eremofortins A and B. In the Roquefort population, we detected no PR toxin nor eremofortins A or B, but found no indel or frameshift mutation, suggesting downregulation. The hypotoxigenic trait of domesticated cheese populations can be hypothesized to be linked to the loss of this ability through trait degeneration and/or the selection of low toxin producers. It may also be due to the fact that populations from other anthropized environments maintained high metabolite diversity as the bioactivities of these compounds are likely important in these ecological niches.