Evolution of the Toxins Muscarine and Psilocybin in a Family of Mushroom-Forming Fungi
PLoS ONE May 23, 2013 Pawel Z. Kosentka, Sarah L. Sprague, Martin Ryberg et al. 79 citations
Mushroom-forming fungi produce many toxic alkaloids, but the evolution of muscarine (a toxin that stimulates the parasympathetic nervous system) and psilocybin (a hallucinogen) had not been studied. This review and new chemical assays of 30 Inocybaceae samples, including tropical and southern-hemisphere species, tested whether muscarine is ancestral in the family. The results show muscarine evolved independently multiple times, with several losses, and is not ancestral for the whole family. It is a shared derived trait for a clade containing three major lineages (Inocybe, Nothocybe, Pseudosperma) whose common ancestor lived about 60 million years ago. Transitions from muscarine-producing ancestors to psilocybin occurred more recently, 10–20 million years ago, after muscarine loss in two separate lineages. Statistical analyses reject a single origin of muscarine-producing taxa.