Forests influence yeast populations vectored by insects into vineyards

Abstract

IntroductionIn the vineyard, yeast communities impact the ripening and fermentation of grapes and are influenced by geographical location, climate, and soil characteristics. Despite the great advancement in our knowledge of the vineyard mycobiota, a key step of the process leading to the definition of the vineyard yeast community is still poorly understood: if geography, climate, and soil influence the mycobiota, potentially through selection, where do the yeast originate from, and how can they reach the vineyard? In this perspective, it is currently acknowledged that forests host several yeast species and that insects, particularly social wasps, can vector and maintain the yeasts known to populate the vineyard. Alas, the conveyance, fostered by insects, of yeasts from the forest to the vineyard has not been proven yet. In this study, we aimed to assess the existence of links between a potential natural source of yeasts (woods), the vectors (social wasps), and the composition of the vineyard mycobiota.MethodsFor this purpose, the mycobiota of wasps caught in six Italian vineyards were analyzed over 2 years through culturomics approaches.ResultsThe results clearly indicate that the presence of wooded areas close to vineyards is associated with particular features of the mycobiota vectored by social wasps. Wasps caught in vineyards near wooded areas bear a higher number of yeast cells and higher biodiversity than insects caught in vineyards far from woods. Furthermore, insects caught in vineyards close to woods bear distinctive yeast populations, encompassing species such as Saccharomyces cerevisiae.DiscussionOverall, our work provides fundamental insights into the ecology of the vineyard mycobiota and highlights the need to maintain a vineyard-woodland mosaic landscape, thus preserving the suitable habitat for yeast species relevant to wine-making.

The Influence of Groves on Aboveground Arthropod Diversity and Evolution in a Vineyard in Southern Romania

“…The members of another species of the genus Vespula, V. vulgaris, sting grapes, eat the contents, and leave only the peel; the affected grapevine is later attacked by fungi or bacteria [25]. In spite of that, some wasps are a crucial vector of the yeast species used in the winemaking process [26]. For instance, Polistes, Vespa, and Vespula play an essential role in the Saccharomyces cerevisiae yeast ecology, responsible for must fermentation in the winemaking process [27].…”

Mutualistic Relationships between Microorganisms and Eusocial Wasps (Hymenoptera, Vespidae)

“…This does not mean that social wasps are unique carriers of yeast, but due to their biological and behavioural characteristics, they represent important carrying agents in the environment. This has been further stressed by Valentini et al [ 79 ] who discovered that wasps collected in areas near forests present a higher number of yeast cells and a wider biodiversity than insects caught in more open areas. This is probably related to the fact that yeasts (including S. cerevisiae ) can also be found in the bark of trees or in other natural substrata [ 70 ].…”

Microbiota Ecosystem Services in Vineyards and Wine: A Review

“…The surrounding ecosystems also seem to be involved in the composition of microbial communities in vineyards. Thus, nearby forests shape the fungal communities in the vineyard, not only because of the natural yeasts they host but also because of the social insects (e.g., wasps) that act as vectors for transporting microorganisms from the forest to the grapes [110][111][112][113].…”