Depside and depsidone synthesis in lichenized fungi : olivetoric and physodic acid chemotype of Pseudevernia furfuracea

Primary biosynthetic enzymes involved in the synthesis of lichen polyphenolic compounds depsides and depsidones are Non-Reducing Polyketide Synthases (NR-PKSs), and cytochrome P450s (CytP450). However, for most depsides and depsidones the corresponding PKSs are unknown. Additionally, in non-lichenized fungi specific fatty acyl synthases (FASs) provide starters to the PKSs. But the presence of such FASs in lichenized fungi remains to be investigated. We implemented comparative genomics and metatranscriptomics to identify the most likely PKS and FASs for the synthesis of olivetoric and physodic acid, the primary depside and depsidone defining the two chemotypes of the lichen Pseudevernia furfuracea.