Genome sequencing progenies of magic mushrooms (Psilocybe subaeruginosa) identifies tetrapolar mating and gene duplications in the psilocybin pathway

Mating in the psilocybin-producing mushroom Psilocybe subaeruginosa is controlled by a tetrapolar system, with compatibility determined by a homeodomain locus (containing one copy each of HD1 and HD2) and a pheromone/receptor locus (with four homologs of the receptor gene STE3). Two additional pheromone/receptor loci homologous to STE3 do not appear to regulate mating. Alleles in the psilocybin gene cluster were homozygous in the parent and did not vary among five haploid siblings. The species and its relatives carry three copies of PsiH genes, but their effect on psilocybin production is unknown. Genetic improvement requires access to diversity from species' centers of origin, identification of trait genes, and strategies to avoid inbreeding depression.

Study at a glance

Abstract

Knowledge of breeding systems and genetic diversity is critical to select and combine desired traits that advance new cultivars in agriculture and horticulture. Mushrooms that produce psilocybin, magic mushrooms, may potentially be used in therapeutic and wellness industries, and stand to benefit from genetic improvement. We studied haploid siblings of Psilocybe subaeruginosa to resolve the genetics behind mating compatibility and advance knowledge of breeding. Our results show that mating in P. subaeruginosa is tetrapolar, with compatibility controlled at a homeodomain locus with one copy each of HD1 and HD2, and a pheromone/receptor locus with four homologs of the receptor gene STE3. An additional two pheromone/receptor loci homologous to STE3 do not appear to regulate mating compatibility. Alleles in the psilocybin gene cluster did not vary among the five siblings and were likely homozygous in the parent. Psilocybe subaeruginosa and its relatives have three copies of PsiH genes but their impact on production of psilocybin and its analogues is unknown. Genetic improvement in Psilocybe will require access to genetic diversity from the centre of origin of different species, identification of genes behind traits, and strategies to avoid inbreeding depression.