Clade III Synthases Add Cyclic and Linear Terpenoids to the Psilocybe Metabolome

Psilocybe cubensis mushrooms, famous for producing the psychedelic compound psilocybin, also possess enzymes that synthesize a variety of other small, potentially bioactive molecules. Four newly identified sesquiterpene synthases, CubB through CubE, are expressed differently in the mushroom's fruiting bodies versus its vegetative mycelium. CubB produces a single compound, nerolidol, while CubC generates multiple sesquiterpenes including β-caryophyllene and α-humulene. CubD and CubE nearly exclusively produce sterpurene. The presence of nerolidol was confirmed in young fruiting bodies and vegetative mycelium. These findings expand understanding of the secondary metabolome of Psilocybe species.

Study at a glance

Abstract

Psilocybe “magic mushrooms” are best known for their indolethylamine psilocybin, yet they encode enzymes for a much more diverse arsenal of small and potentially bioactive molecules. Herein, four Psilocybe cubensis clade III sesquiterpene synthases, CubB‐CubE, whose genes are differently expressed in fruiting bodies compared to vegetative mycelium are reported. CubB‐CubE were functionally characterized in vitro by product formation assays with heterologously produced enzymes and in vivo by transgene expression in Aspergillus niger , followed by extensive gas chromatography‐mass spectrometry analyzes. CubB was identified as a single product (3 R, 6 E )‐(‐) ‐ nerolidol synthase. CubC is a multiproduct enzyme producing β‐caryophyllene, β‐elemene, α‐humulene, and β‐farnesene. CubD and CubE catalyze (near‐)exclusively sterpurene formation. P. cubensis young fruiting bodies and vegetative mycelium were analyzed for sesquiterpenes, which verified the presence of the CubB product α‐(3 R, 6 E )‐(‐) ‐ nerolidol. As various Psilocybe species encode highly similar enzymes, this study contributes generally to the as‐yet little‐understood secondary metabolome of the genus.