Bis-naphthopyrone pigments protect filamentous ascomycetes from a wide range of predators

Abstract

It is thought that fungi protect themselves from predation by the production of compounds that are toxic to soil-dwelling animals. Here, we show that a nontoxic pigment, the bis-naphthopyrone aurofusarin, protects Fusarium fungi from a wide range of animal predators. We find that springtails (primitive hexapods), woodlice (crustaceans), and mealworms (insects) prefer feeding on fungi with disrupted aurofusarin synthesis, and mealworms and springtails are repelled by wheat flour amended with the fungal bis-naphthopyrones aurofusarin, viomellein, or xanthomegnin. Predation stimulates aurofusarin synthesis in several Fusarium species and viomellein synthesis in Aspergillus ochraceus . Aurofusarin displays low toxicity in mealworms, springtails, isopods, Drosophila , and insect cells, contradicting the common view that fungal defence metabolites are toxic. Our results indicate that bis-naphthopyrones are defence compounds that protect filamentous ascomycetes from predators through a mechanism that does not involve toxicity.

Fullerol C60(OH)24 Nanoparticles Affect Secondary Metabolite Profile of Important Foodborne Mycotoxigenic Fungi In Vitro

“…The aurofusarin is dimeric naphtho-γ-pyrone and is produced by many ascomycetes where predation and mechanical damage stimulate aurofusarin synthesis. It is a red pigment known from pure culture of the fungi (Figure 6b-8)) or from maize ears that are infected with F. graminearum [43][44][45]. In general, aurofusarin concentration in growth media was decreased at all isolates, except when 100 ng mL −1 of FNP was applied during F. verticillioides growth (Figure 6c-1).…”

Genome Sequence of Trichoderma lixii MUT3171, A Promising Strain for Mycoremediation of PAH-Contaminated Sites

“…Among the PKS clusters ( Figure 5 ), three gene clusters of T. lixii MUT3171 resemble those for the production of naphthopyrone in Aspergillus nidulans FGSC A4 (BGC0000107), betaenone in Phoma betae (BGC0001264 and BGC0001280), monoascorubrin in Talaromyces marneffei (BGC0000099) and stipitatic acid in Talaromyces stipitatus ATCC 10500 (BGC0000154). Naphthopyrones are pigments that protect Ascomycetes from a wide range of predators [ 70 ], but their derivatives can display cytotoxic activity [ 71 ]. Betaenones are phytotoxic and their production was not confirmed in Trichoderma .…”

Infection cushions of Fusarium graminearum are fungal arsenals for wheat infection

“…The cluster for aurofusarin biosynthesis is the only one specifically induced in RH. Aurofusarin is a red pigment produced by different Fusarium species, belonging to polyphenol, more accurately bis-naphthopyrone pigments (Frandsen et al, 2006;Xu et al, 2019). In a previous study, deletion of the F. graminearum pks12 gene (FGSG_02324) F I G U R E 6 FgPE1 is secreted and mainly localized at the fungal-plant interface.…”

“…Recently, aurofusarin has been described to inhibit Lactobacillus and Bifidobacterium, but not E. coli (Sondergaard et al, 2016). Excitingly, it has been described as an antifeedant that accumulates in high amounts to protect Fusarium fungi from a wide range of insects (Xu et al, 2019). The microbiology of the phyllosphere is, in general, not very well understood, but it seems safe to assume that RH of F. graminearum ward off other microbes during colonization of the palea's surface.…”