Different Mushrooms Evolved Separate Routes To Produce Psilocybin

“Magic mushrooms” have fascinated humans for centuries, not only for their psychedelic effects but also for their potential in treating depression.

Researchers at Friedrich Schiller University Jena and the Leibniz Institute for Natural Product Research and Infection Biology (Leibniz-HKI) have discovered that two different types of fungi independently evolved separate biochemical pathways to produce psilocybin, the compound responsible for these effects.

Psilocybin in fungi

“This concerns the biosynthesis of a molecule that has a very long history with humans,” said corresponding author Dr. Dirk Hoffmeister, head of pharmaceutical microbiology at Friedrich Schiller University Jena and Leibniz-HKI. “We are referring to psilocybin, a substance found in so-called magic mushrooms, which our body converts into psilocin – a compound that can profoundly alter consciousness.”

Psilocybin is the main psychoactive molecule in magic mushrooms. Once ingested, it is broken down in the body to psilocin, which acts on serotonin receptors in the brain and alters perception.

“Psilocybin not only triggers psychedelic experiences, but is also considered a promising active compound in the treatment of therapy-resistant depression,” said Hoffmeister.

Psilocybin was first isolated from Psilocybe mushrooms in the 1950s, and researchers later identified the gene cluster “psi” responsible for its production.

Yet psilocybin is not confined to Psilocybe. It also appears in other fungi such as Inocybe, Gymnopilus and Panaeolus, which raises a puzzle: do they use the same enzyme toolkit or a different one?

Earlier work suggested Inocybe corydalina (I. corydalina), a fiber cap mushroom, produces psilocybin without the typical Psilocybe genes, hinting at a different biochemical route.

The new study aims to test that possibility directly. Hoffmeister and his team sought to biochemically characterize Inocybe enzymes and pathways, and to test whether psilocybin biosynthesis evolved independently in this genus.

Two independent biochemical routes to psilocybin in fungi

The researchers investigated a set of five genes, known as the ips cluster, suspected of directing psilocybin production in I. corydalina. Each gene was expressed in Escherichia coli, allowing the team to produce the corresponding enzymes and test them in the lab. Using enzyme activity assays and liquid chromatography-mass spectrometry, they could track which reactions were carried out. They also built protein models to compare the I. corydalina enzymes to the well-studied set in Psilocybe mushrooms.

I. corydalina relied on an entirely different toolkit, with a completely different set of enzymes to produce psilocybin. None of the reactions overlapped between the two pathways.

“It was like looking at two different workshops, but both ultimately delivering the same product. In the fiber caps, we found a unique set of enzymes that have nothing to do with those found in Psilocybe mushrooms. Nevertheless, they all catalyze the steps necessary to form psilocybin,” said lead author Dr. Tim Schäfer, a doctoral researcher in Hoffmeister’s team.

The pathway in I. corydalina was also branched. Alongside psilocybin, the mushrooms produced baeocystin, another related compound, as an end product.

“Here, nature has actually invented the same active compound twice,” said Schäfer.  

This is an example of convergent evolution, where two unrelated fungi independently arrived at the same active compound.

Implications for psilocybin production

The question of why two different types of fungi both produce psilocybin remains open.

“The real answer is: we don’t know. Nature does nothing without reason. So there must be an advantage to both fiber cap mushrooms in the forest and Psilocybe species on manure or wood mulch producing this molecule – we just don’t know what it is yet,” said Hoffmeister.

One idea is that psilocybin, or more specifically its breakdown products, may act as a defense.

“Even the smallest injuries cause Psilocybe mushrooms to turn blue through a chemical chain reaction, revealing the breakdown products of psilocybin. Perhaps the molecule is a type of chemical defense mechanism,” said Hoffmeister.

Beyond biology, the work has practical implications.

“Now that we know about additional enzymes, we have more tools in our toolbox for the biotechnological production of psilocybin,” said Hoffmeister.

“We hope that our results will contribute to the future production of psilocybin for pharmaceuticals in bioreactors without the need for complex chemical syntheses,” Schäfer added.

The evolutionary origin of the Inocybe genes is unknown, and the ecological function of psilocybin is still speculative. Other fungi, such as Massospora, also produce it, raising the possibility of further independent pathways.

What is clear is that this study provides the first biochemical evidence for two distinct routes to psilocybin, highlighting fungal diversity and its potential for drug development.

 

Reference: Schäfer T, Haun F, Rupp B, Hoffmeister D. Dissimilar reactions and enzymes for psilocybin biosynthesis in Inocybe and Psilocybe mushrooms. Angew Chem Int Ed. 2025:e202512017. doi: 10.1002/anie.202512017

 

This article is a rework of a press release issued by the Leibniz Institute. Material has been edited for length and content.