This discovery by a research team from the University of Florence, the Foundation Edmund Mach of San Michele all'Adige and the institute for Bio-meteorology of CNR, the national research institute and lead by Duccio Cavalieri, has documented for the first time the sexual behaviour of yeast in its natural environment, reconstructing the places and steps in which mating of different strains happens.
The Proceedings of the National Academy of Sciences (PNAS) marked this work among those of major interest and Science journal has already commented on it in the "news and views" section (“Social wasps are a Saccharomyces mating nest”, doi: 10.1073/pnas.1516453113).
“We already discovered 2012 - says Cavalieri, associate professor of Microbiology at the University of Florence - that wasps carried in their intestines the yeast Saccharomyces cerevisiae, depositing it on ripe grape berries, where it can naturally jump-start wine fermentation”.Researchers posed the question of what was happening to yeast during their stay inside the wasps' guts. To find out, they have inoculated the insects five different strains of S. cerevisiae, and compared these yeasts with colonies grown in laboratory.
“After hibernation, the wasps intestine contains more hybrids of parental strains than parents - explains Cavalieri. - We have proved that the intestine is the main environment in which Saccharomyces cerevisiae yeasts mate and outcross with other wild strains found in nature (such as those on tree bark), thus promoting the selection of strains particularly suitable to withstand the stress of wine and beer fermentations. It is in fact the long permanence in such a confined environment - continues Cavalieri - that nurtures the generation of gametes and the outcrossing.”
“Wasps are endangered by environmental deterioration - comments Stefano Turillazzi, professor of Zoology at the University of Florence and part of the team -. The biodiversity of these and other social insects such as hornets has an importance going beyond their role of pollinators. It has to do also with the safeguarding of typical microbial heritage, a key factor in the quality and typicality of our products”.