Genetic characterisation and breeding of wine yeasts

[摘要] ENGLISH ABSTRACT:To remain competitive in the market place, the South African wine industry willhave to direct well-planned yeast strain-development programmes. However, thewinemaker can only benefit from the extensive biochemical and molecularinformation of the yeast cell and the impressive arsenal of genetic techniquesavailable, if the wine industry defines its requirements in genetic terms. Thesuccessful application of these genetic and recombinant deoxyribonucleic acid(DNA) techniques in breeding programmes depends on the availability of rapidand reliable techniques to differentiate between parental and hybrid strains.Ten strains of Saccharomyces cerevisiae used for commercial production ofwine in South Africa, were characterised by electrophoretic banding patterns oftotal soluble cell proteins, DNA restriction fragments and chromosomal DNA.Variations in the protein and DNA profiles of strains N6, N21, N66, N76, N95and N97 were apparent in the number, position and intensity of the bands.Strains N93 and N181 originated from the same culture and, as expected,displayed the same characteristic protein, DNA restriction fragment andchromosomal banding patterns. Similar protein and DNA profiles were alsoobtained for killer strain N96 and strain N91. Strain N91 is a derivative of strainN96, cured of the K2 killer character. Results obtained by electrophoreticfingerprinting and karyotyping corresponded well, indicating that thesetechniques are valuable in the identification and quality control of industrial wineyeasts.The value of electrophoretic fingerprinting and karyotyping was alsodemonstrated in a breeding programme. The aim of this breeding programmewas to obtain hybrids that combine the desired oenological characteristics ofstrains N76 and N96, and of strains N96 and N181. The protein banding patternsof hybrids USM21, USM22 and USM23 were identical and contained acombination of prominent unique bands present in the profiles of parentalstrains, N76 and N96H (N96H is a haploid derived from N96). The DNArestriction fragment profiles of hybrids USM21, USM22 and USM23 containedslight variations, whereas their profiles were quite different from those of theirparental strains, N76 and N96H. The contour clamped homogeneous electricfield (CHEF) karyotypes of hybrids USM21, USM22 and USM23 were identicalbut differed from those of their parental strains, N76 and N96H. The proteinprofiles of hybrid USM30 and its parental strains, N96H and N181, were similar,whereas their DNA restriction fragment banding patterns and CHEF karyotypesshowed discrete differences. In conclusion, protein and DNA fingerprinting techniques were found to be valuable in selecting four hybrid killer strains aftermass spore-cell mating. These four killer hybrids contain desirable oenologicalproperties long sought after by the South African wine industry. Fermentationtrials and evaluation of these hybrids were conducted independently by theDeparment of Oenology, University of Stellenbosch and by Stellenbosch Farmers'Winery and they have now been released for commercial wine production.

[发布机构] Stellenbosch University