Lucy Joseph* and Linda Bisson  
*Department of Viticulture and Enology, University of California, Davis, Davis, CA 95616 (cmjoseph@ucdavis.edu)

Multiplex PCR in conjunction with microsatellite DNA analysis has been used to genetically type microbes over the last dozen years. It has been used successfully to type strains of Saccharomyces cerevisiae isolated from around the globe and there are several publicly available sequence comparison databases. We have used this technique over the last four years to type native California Saccharomyces strains collected from different isolated environments around central California. We initially used a database created in New Zealand that included over 80 commercially available yeasts and Saccharomyces isolated from New Zealand and other geographic areas around the world. The database also included over 30 sequenced strains from the Saccharomyces Genome Resequencing Project. We added to the database ~30 isolates from Chile and California and >50 additional commercial strains. This generated sequence from enough native isolate strains to determine a finger-print for autochthonous Saccharomyces strains in California. We then evaluated the fingerprints of ~100 strains from both the UC Davis Viticulture and Enology Wine Yeast and Bacteria Collection and the UC Davis Food Science and Technology Phaff Yeast Collection. This was done to determine whether S. cerevisiae strains that have been in the collection for up to 79 years, with no information on their origins or characterized as natural isolates, had fingerprints consistent with recently isolated native yeasts or with commercial or laboratory yeast. We found that ~15% of the strains evaluated had fingerprints similar to the more recent set of autochthonous California isolates, with the oldest autochthonous accession entered into the collection in 1939. Another 20% were characterized as being possible natives or hybrids. The other 65% were closely related to commercial or laboratory research strains.

Funding Support: UC Davis Department of Viticulture and Enology, UC Davis College of Agriculture and Environmental Sciences