Article

Antonie van Leeuwenhoek

, Volume 89, Issue 1, pp 27-37

First online:

A homozygous diploid subset of commercial wine yeast strains

  • John E. BradburyAffiliated withSchool of Biological Sciences, University of Auckland
  • , Keith D. RichardsAffiliated withSchool of Biological Sciences, University of Auckland
  • , Heather A. NiedererAffiliated withSchool of Biological Sciences, University of Auckland
  • , Soon A. LeeAffiliated withSchool of Biological Sciences, University of Auckland
  • , P. Rod DunbarAffiliated withSchool of Biological Sciences, University of Auckland
  • , Richard C. GardnerAffiliated withSchool of Biological Sciences, University of Auckland Email author 

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Abstract

Genetic analysis was performed on 45 commercial yeasts which are used in winemaking because of their superior fermentation properties. Genome sizes were estimated by propidium iodide fluorescence and flow cytometry. Forty strains had genome sizes consistent with their being diploid, while five had a range of aneuploid genome sizes that ranged from 1.2 to 1.8 times larger. The diploid strains are all Saccharomyces cerevisiae, based on genetic analysis of microsatellite and minisatellite markers and on DNA sequence analysis of the internal transcribed spacer (ITS) region of nuclear ribosomal DNA of four strains. Four of the five aneuploid strains appeared to be interspecific hybrids between Saccharomyces kudriavzevii and Saccharomyces cerevisiae, with the fifth a hybrid between two S. cerevisiae strains. An identification fingerprint was constructed for the commercial yeast strains using 17 molecular markers. These included six published trinucleotide microsatellites, seven new dinucleotide microsatellites, and four published minisatellite markers. The markers provided unambiguous identification of the majority of strains; however, several had identical or similar patterns, and likely represent the same strain or mutants derived from it. The combined use of all 17 polymorphic loci allowed us to identify a set of eleven commercial wine yeast strains that appear to be genetically homozygous. These strains are presumed to have undergone inbreeding to maintain their homozygosity, a process referred to previously as ‘genome renewal’.

Keywords

Flow cytometry Internal transcribed spacer Microsatellite Minisatellite Polymorphism Saccharomyces