Matthias Bougreau,* Marie Bugarel, and Guy Loneragan
*Texas Tech University, Department of Animal and Food Sciences, International Center for Food Industry Excellence, Box 42141, Lubbock, TX 79409 (matthias.bougreau@ttu.edu)

The main yeast species present on grapes, leaves, and surrounding soils of Tempranillo and Cabernet Sauvignon vineyards in the hot, semi-arid climate of the Texas High Plains area were investigated, as well as the presence and evolution of yeast species during natural fermentations of Tempranillo grapes from the same vineyards. Characterization of yeast species was performed using the culture-dependent ITS-RFLP method and genome sequencing. Yeast species recovered from grapes, leaves, and soils were mainly dominated by Aureobasidium pullulans, Cryptococcus species, Filobasidium species and Naganishia species, typical members of the vineyard environment. Only one isolate of potential enological interest, Lachancea thermotolerans, was recovered from the vineyard environment. However, natural fermentation revealed the presence of the fermenting yeast Saccharomyces cerevisiae, L. thermotolerans, and Hanseniaspora species. The presence of L. thermotolerans is of extreme interest for winemaking in the Texas High Plains. Indeed, this species has been previously shown to acidify musts, and one of the main characteristics of grapes grown in the Texas High Plains is their lack of acidity. These findings agree with the theory that microorganisms present in the vineyards of a specific area could be more adapted for fermentation of grapes grown in the same area, and could lead to the production of more typical and natural wines.

Funding Support: Texas Tech University