Social wasps are a Saccharomyces mating nest.

Irene Stefanini (1) , Leonardo Dapporto (2) , Luisa Berná (3) , Mario Polsinelli (4) , Stefano Turillazzi (4) , Duccio Cavalieri (4, 1)

1 Fondazione Edmund Mach - Functional genomics
2 Institut de Biologia Evolutiva (CSIC-UPF)
3 Institut Pasteur de Montevideo
4 UniFI - Università degli Studi di Firenze = University of Florence = Université de Florence

The reproductive ecology of Saccharomyces cerevisiae is still largely unknown. Recent evidence of interspecific hybridization, high levels of strain heterozygosity, and prion transmission suggest that outbreeding occurs frequently in yeasts. Nevertheless, the place where yeasts mate and recombine in the wild has not been identified. We found that the intestine of social wasps hosts highly outbred S. cerevisiae strains as well as a rare S. cerevisiae×S. paradoxus hybrid. We show that the intestine of Polistes dominula social wasps favors the mating of S. cerevisiae strains among themselves and with S. paradoxus cells by providing a succession of environmental conditions prompting cell sporulation and spores germination. In addition, we prove that heterospecific mating is the only option for European S. paradoxus strains to survive in the gut. Taken together, these findings unveil the best hidden secret of yeast ecology, introducing the insect gut as an environmental alcove in which crosses occur, maintaining and generating the diversity of the ascomycetes.

Mots clés: social wasps; yeasts; Saccharomyces cerevisiae; Saccharomyces paradoxus; hybrids

Domaines: Sciences du Vivant [q-bio]; Ecologie, Environnement

Irene Stefanini, Leonardo Dapporto, Luisa Berná, Mario Polsinelli, Stefano Turillazzi, et al.. Social wasps are a Saccharomyces mating nest.. Proceedings of the National Academy of Sciences of the United States of America, 2016, 113 (8), pp.2247-51. ⟨10.1073/pnas.1516453113⟩. ⟨pasteur-01501062⟩