VOLUME 6 NUMBER 1 (January to June 2013)

by Cynthia T. Hedreyda* and Zahara Joy A. Guiamal

National Institute of Molecular Biology and Biotechnology, College of Science, University of thePhilippines, Diliman, Quezon City, Philippines 1101

The availability of reliable procedures to check ifdesirable wine strains of Saccharomyces cerevisiaeare maintained is valuable for wine producers toensure the quantity and quality of wines produced.Random Amplification of Polymorphic DNA(RAPD) in a previous study, generated Polymerase ChainReaction (PCR) profiles that could distinguish S. cerevisiae winestrains (that exhibited growth in 10% and 15% ethanol) from anon-wine strain (that exhibited growth inhibition in 10 and 15%ethanol) and wine strains from one another. In this study, delta(δ) typing and sequence analysis of three specific genes (erg2,hsp104 and sod2) implicated in alcohol tolerance wereperformed in search of a faster and cheaper procedure todistinguish strains of S. cerevisiae. The use of delta primer pair,δ₁₂ / δ₂, resulted in a distinct profile for each of yeast strainsstudied. Compared to RAPD, which makes use of severalrandom primers and several PCR runs, delta typing involves onePCR run and uses a single δ primer pair. Sequence analysis ofthree S. cerevisiae genes that code for proteins involved in majormechanisms proposed for alcohol tolerance of the species,revealed single (for the erg2 and hsp104 genes) to multiple (forthe sod2 gene) nucleotide variations. The nucleotidepolymorphisms observed for the erg2 and sod2 genes are notexpected to result in amino acid variation while thepolymorphisms found in the amplified fragments of the hsp104gene resulted in amino acid variation at position 236. Nucleotideand protein polymorphisms in these genes, however, could notdiscriminate the yeast strains studied and the variation did notcorrelate with the reported strain differences in alcoholtolerance. Results of this study suggest that delta (δ) typing withprimers δ₁₂ and δ₂, is more discriminatory, faster, and lessexpensive than RAPD and is recommended to be the firstprocedure to perform in trying to discriminate wine strains ofS. cerevisiae. Polymorphisms observed in the three genes, erg2,hsp104 and sod2, cannot be used as a basis for designing PCRprimers that could generate discriminating profiles of winestrains versus the non-wine strain of yeast used. Sequence analysisof several other genes implicated in alcohol tolerance isrecommended in order to identify a gene or a group of genes withnucleotide and amino acid sequence variation that coulddistinguish wine strains of S. cerevisiae.