Vitis species, vintage, and alcoholic fermentation do not drive population structure in Starmerella bacillaris (synonym Candida zemplinina) species

The yeast species Starmerella bacillaris (synonym Candida zemplinina) is widely associated with oenological ecosystems and is frequently isolated from grape and grape must. Previous work showed that the genetic diversity of this species is high in wine environments and it is shaped by geographic location. Most analysed C. zemplinina strains, however, have been isolated from Vitis vinifera, disregarding the existence of other worldwide-distributed Vitis species used in winemaking. In this work, we address the impact of the Vitis species and geographic location on the genetic diversity of C. zemplinina. Microsatellite genotyping analysis was applied to two remarkable populations of C. zemplinina from Argentina and Portugal (Azores Archipelago), isolated from neighbouring V. vinifera and Vitis labrusca vineyards. The study also included a large population of previously characterized worldwide-isolated C. zemplinina strains. Genetic analyses confirmed that geographic localization significantly shaped the genetic diversity of C. zemplinina. No genetic differentiation on the basis of the Vitis species was recorded, indicating that C. zemplinina populations from neighbouring V. vinifera and V. labrusca vineyards are genetically homogeneous. In addition, no impact of the vintage was found on the C. zemplinina populations being both highly diversified and homogeneous during initial stages of alcoholic fermentation. Altogether, these results confirmed that winemaking-related factors (i.e., vintage, Vitis species, and alcoholic fermentation) do not impact the genetic diversity of C. zemplinina and that only geographic localization significantly shapes this yeast species.