title: Role of social wasps in Saccharomyces cerevisiae ecology and evolution.
abstract: Saccharomyces cerevisiae is one of the most important model organisms and has been a valuable asset to human civilization. However, despite its extensive use in the last 9,000 y, the existence of a seasonal cycle outside human-made environments has not yet been described. We demonstrate the role of social wasps as vector and natural reservoir of S. cerevisiae during all seasons. We provide experimental evidence that queens of social wasps overwintering as adults (Vespa crabro and Polistes spp.) can harbor yeast cells from autumn to spring and transmit them to their progeny. This result is mirrored by field surveys of the genetic variability of natural strains of yeast. Microsatellites and sequences of a selected set of loci able to recapitulate the yeast strain's evolutionary history were used to compare 17 environmental wasp isolates with a collection of strains from grapes from the same region and more than 230 strains representing worldwide yeast variation. The wasp isolates fall into subclusters representing the overall ecological and industrial yeast diversity of their geographic origin. Our findings indicate that wasps are a key environmental niche for the evolution of natural S. cerevisiae populations, the dispersion of yeast cells in the environment, and the maintenance of their diversity. The close relatedness of several wasp isolates with grape and wine isolates reflects the crucial role of human activities on yeast population structure, through clonal expansion and selection of specific strains during the biotransformation of fermented foods, followed by dispersal mediated by insects and other animals.
authors: Dipartimento di Farmacologia,  University of Florence, 50139, Florence,  Italy.
authors: Irene
authors: I
authors: Stefanini
authors: Leonardo
authors: L
authors: Dapporto
authors: Jean-Luc
authors: JL
authors: Legras
authors: Antonio
authors: A
authors: Calabretta
authors: Monica
authors: M
authors: Di Paola
authors: Carlotta
authors: C
authors: De Filippo
authors: Roberto
authors: R
authors: Viola
authors: Paolo
authors: P
authors: Capretti
authors: Mario
authors: M
authors: Polsinelli
authors: Stefano
authors: S
authors: Turillazzi
authors: Duccio
authors: D
authors: Cavalieri
mesh_terms: D000818:Animals; D005075:Biological Evolution; D004064:Digestive System / Q000382:microbiology; D055669:Ecological and Environmental Phenomena; D016681:Genome, Fungal / Q000235:genetics; D006801:Humans; D018895:Microsatellite Repeats / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000302:isolation & purification; D012621:Seasons; D012919:Social Behavior; D014863:Wasps / Q000235:genetics / Q000382:microbiology*