Functional convergence of fungal polyketide synthases

Fungi produce a broad spectrum of interesting secondary metabolites. Perhaps the most important class are the polyketides, which are initially assembled by polyketide synthases and subsequently modified by further enzymes. Some polyketides are characteristic for large groups of fungi whereas others have a widely scattered occurrence in different lineages of fungi. In the latter case it is unclear whether the biosynthesis of these compounds was lost in lineages or whether their production has evolved repeatedly. Lichen mycobionts represent diverse groups of fungi which are rich in secondary metabolites. Mycobionts of different groups producing the same compounds are here used to test whether similar products involve the action of orthologous polyketide synthases or whether the same products can be assembled by unrelated polyketide synthases. The latter situation will demonstrate that the evolution of secondary metabolism of fungi is more dynamic than it would be predicted by the simplicistic idea that the same genes are responsible for the same products.

Fungi produce a broad spectrum of interesting secondary metabolites. Perhaps the most important class are the polyketides, which are initially assembled by polyketide synthases and subsequently modified by further enzymes. Some polyketides are characteristic for large groups of fungi whereas others have a widely scattered occurrence in different lineages of fungi. In the latter case it is unclear whether the biosynthesis of these compounds was lost in lineages or whether their production has evolved repeatedly. Lichen mycobionts represent diverse groups of fungi which are rich in secondary metabolites. Mycobionts of different groups producing the same compounds are here used to test whether similar products involve the action of orthologous polyketide synthases or whether the same products can be assembled by unrelated polyketide synthases. The latter situation will demonstrate that the evolution of secondary metabolism of fungi is more dynamic than it would be predicted by the simplicistic idea that the same genes are responsible for the same products.