Fungal defense strategies

Abstract

Similar to plants, fungi serve other organisms as food source. Consequently, fungi had to evolve defense strategies against fungivores. Even though the defense mechanisms of fungi have not been studied intensively, some striking examples exist that demonstrate both parallels to plant defense and peculiarities. In particular, the fruiting bodies of mushrooms are a vast source of secondary metabolites many of which comprise unprecedented natural products.A pungent taste, for example, from chalciporone, deters mammals from feeding. Highly toxic peptides such as amanitins provide fungi with efficient weapons against attack. Hallucinogenic compounds, for example, ibotenic acid or psilocybin, confuse feeders and thus prevent them from further feeding. Compounds such as strobilurins or 2-chloro-4-nitrophenol act as potent fungicides and thus stop growth of other organisms in surrounding of the producing fungi.Some fungi store their defense compounds as inactive safe precursors that are activated upon attack to release highly toxic compounds. For example, the terpenoid dialdehyde velleral is generated by action of an esterase from stearoylvelutinal; HCN is released by the mushroom Aleurodiscus amorphus upon wounding from the cyanohydrine ether aleurodisconitrile by an enzymatic oxidative process.