Molecular identification of yeast species colonising grape fruits in Nova Scotia vineyards

Barasubiye, T*., L. Fan and C. Doucette. 2017. Molecular identification of yeast species colonising grape fruits in Nova Scotia vineyards. Oral presentation at the Joint Meeting of the Canadian Phytopathological Society (CPS) and the Canadian Society of Agronomy. Winnipeg, Manitoba. June 18-22nd.

Abstract

The diversity of yeasts involved in wine fermentation can impact the wine parameters such as pH, alcohol level, viscosity, color, flavor, and aroma. The goal of this study was to isolate and identify naturally occurring yeasts associated with vineyards in Nova Scotia. Grape cultivars of L’Acadie, Riesling, New York Muscat, and Pinot Noir grown were sampled at multiple vineyard sites within the Annapolis Valley of Nova Scotia. Two sub-samples of approximately 25g each of grapes were blended. Serial diluted samples were surface plated on potato dextrose agar supplemented with 0.1g/L of chloramphenicol and incubated at 25°C for 72 hours. Yeasts were isolated and then purified on YM agar. The internal transcribed spacer regions and the D1/D2 domains of the nuclear 28S rRNA gene and the second largest subunit of RNA polymerase II were sequenced for 60 isolates. Sequencing data have allowed to recognize the 12 following yeast species: Hanseniaspora uvarum (Niehaus) Shehata, Mrak & Phaff; Saccharomyces bayanus Sacc.; Saccharomycopsis crataegensis Kurtzman & Wick; Pichia kluyveri Bedford; Aureobasidium pullulans (de Bary & Löwenthal) G. Arnaud; Sporidiobolus pararoseus Fell & Tallman; Rhodotorula glutinis (Fresen.) F.C. Harrison; Filobasidium magnum (Lodder & Kreger-van Rij) X.Z. Liu, F.Y. Bai, M. Groenew. & Boekhout. Rhodotorula mucilaginosa (A. Jörg.) F.C. Harrison; Bullera alba (W.F. Hanna) Derx; Papiliotrema flavescens (Saito) X.Z. Liu, F.Y. Bai, M. Groenew. & Boekhout; and Naganishai diffluens (Zach) X.Z. Liu, F.Y. Bai, M. Groenew. & Boekhout. This study represents the first attempt to determine yeast species colonising grape fruits in vineyards in Nova Scotia.

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