The psychedelic alkaloid psilocybin, driving Psychedelics and Drug Studies, first evolved in the mushroom genus Psilocybe around 67 million years ago. Evolutionary biology indicates its biosynthetic gene cluster transferred horizontally 4 to 5 times to other fungi between 40 and 9 million years ago. Using 71 fungal metagenomes, Phylogenetics of 2,983 gene families reveals Psilocybe's deep Biology. Two distinct psilocybin gene cluster arrangements correspond to major clades, suggesting independent acquisitions of this alkaloid's chemical synthesis, impacting Fungal Biology and Applications.
Psilocybin, the psychoactive compound found in dozens of mushroom species, is being studied for treating addiction, depression, and end-of-life suffering. New genome analyses of the hallucinogenic mushrooms Psilocybe cyanescens and Pluteus salicinus confirm and refine the genes responsible for psilocybin biosynthesis, showing that a previously implicated transcription factor is not part of that gene cluster. The mushroom Inocybe corydalina produces psilocybin but lacks the established cluster, and an alternative cluster is described. Meta-transcriptome analysis of wild mushrooms reveals gene expression from fly larvae growing inside Psilocybe cyanescens, and these larvae were reared to adulthood. Psilocybin does not fully protect against insect consumption, suggesting its ecological role as a defense compound may need rethinking.