Microarray karyotyping of commercial wine yeast strains reveals shared, as well as unique, genomic signatures.
Barbara Dunn (1), R. Paul Levine (2), Gavin Sherlock (1)
(1) Dept of Genetics, Stanford University Med Ctr, 300 Pasteur Ave, Stanford, CA, 94305, USA; (2) Dept of Biological Sciences, Stanford University, Stanford, CA 94305 USA
Genetic differences between yeast strains used in wine-making may account for some of the variation seen in their fermentation properties as well as in differing sensory characteristics of the final wine product itself. To investigate this, we have determined genomic differences among several Saccharomyces cerevisiae wine strains by using a 'microarray karyotyping' (also known as 'array-CGH') technique. We have studied four commercial wine yeast strains, assaying three independent isolates from each strain. All four wine strains showed common differences with respect to the laboratory S. cerevisiae strain S288C. We observed very little intra-strain variation between the different commercial isolates of a given strain, although an exception to this was seen among the Montrachet isolates. A moderate amount of inter-strain genomic variation was observed, mostly in the form of depletions or amplifications of single genes; these differences allowed unique identification of each strain. Many of the inter-strain differences appear to be in transporter genes, including genes involved in drug response. We therefore used halo assays to investigate the response of these strains to three different fungicidal drugs. Strains with fewer copies of the CUP1 loci showed hypersensitivity to sulfomethuron methyl. We have also begun a similar investigation of 'wild' wine yeast strains to see how similar their microarray karyotypes are to those of the commercial wine yeast strains.