title: The vintage effect overcomes the terroir effect: a three year survey on the wine yeast biodiversity in Franciacorta and Oltrepò Pavese, two northern Italian vine-growing areas.
abstract: A three year survey on the dominant yeast populations in samples of air, must and wine in different vineyards and cellars of two northern Italian vine-growing territories (six sites in Franciacorta and eight sites in Oltrepò Pavese areas) was carried out. A total of 505 isolates were ascribed to 31 different species by RFLP analysis of the ITS1-5.8SrRNA-ITS2 region and partial sequence analysis of the 26S rRNA gene. The most commonly found species were Saccharomyces cerevisiae (frequency, F' = 58.7%; incidence, I' = 53.5%), Hanseniaspora uvarum (F' = 14.3%; I' = 5.3%), Metschnikowia fructicola (F' = 11.1%; I' = 5.0%) and Torulaspora delbrueckii (F' = 10.3%; I' = 3.8%). Among 270 S. cerevisiae new isolates, 156 (57.8%) revealed a different genetic pattern through polymorphism analysis of the interdelta regions by capillary electrophoresis, while 47 isolates (17.4 %) were clones of starter cultures. By considering the Shannon-Wiener index and results of principal component analysis (PCA) analyses, the year of isolation (vintage) proved to be a factor that significantly affected the biodiversity of the yeast species, whereas the geographical site (terroir) was not. Seventy-five per cent of S. cerevisiae isolates gathered in a unique cluster at a similarity level of 82%, while the remaining 25% were separated into minor groups without any evident relationship between δ-PCR profile and territory, year or source of isolation. However, in six cases a similar strain appeared at the harvesting time both in Franciacorta and Oltrepò Pavese areas, whereas surprisingly no strain was reisolated in the same vineyard or cellar for consecutive years.
authors.affiliation: Department of Food, Environmental and Nutrition Sciences, Università degli Studi di Milano, Milano, Italy.
authors.forename: Ileana
authors.initials: I
authors.lastname: Vigentini
authors.affiliation: Department of Agricultural and Environmental Sciences, Università degli Studi di Milano, Milano, Italy.
authors.forename: Gabriella
authors.initials: G
authors.lastname: De Lorenzis
authors.affiliation: Department of Food, Environmental and Nutrition Sciences, Università degli Studi di Milano, Milano, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Fabrizio
authors.affiliation: Department of Food, Environmental and Nutrition Sciences, Università degli Studi di Milano, Milano, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Valdetara
authors.affiliation: Consorzio per la Tutela del Franciacorta, Erbusco, Brescia, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Faccincani
authors.affiliation: ex Consorzio Tutela Vini Oltrepò Pavese, Torrazza Coste, Pavia, Italy.
authors.forename: Carlo Alberto
authors.initials: CA
authors.lastname: Panont
authors.affiliation: Department of Food, Environmental and Nutrition Sciences, Università degli Studi di Milano, Milano, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Picozzi
authors.affiliation: Department of Life Sciences, Università degli Studi di Modena e Reggio Emilia, Italy.
authors.forename: Serena
authors.initials: S
authors.lastname: Imazio
authors.affiliation: Department of Agricultural and Environmental Sciences, Università degli Studi di Milano, Milano, Italy.
authors.forename: Osvaldo
authors.initials: O
authors.lastname: Failla
authors.affiliation: Department of Food, Environmental and Nutrition Sciences, Università degli Studi di Milano, Milano, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Foschino
mesh_terms: D000391:Air Microbiology; D044822:Biodiversity; D004271:DNA, Fungal / Q000235:genetics; D005285:Fermentation; D007218:Industrial Microbiology; D007558:Italy; D008969:Molecular Sequence Data; D010802:Phylogeny; D027843:Vitis / Q000382:microbiology*; D014920:Wine / Q000032:analysis / Q000382:microbiology*; D015003:Yeasts / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D004271:DNA, Fungal