Evaluation of different genetic procedures for the generation of artificial hybrids in Saccharomyces genus for winemaking

PÉREZ-TRAVÉS, L.; LOPES C.A.; BARRIO E.; QUEROL A.

INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY

ELSEVIER SCIENCE BV

Lugar: Torino; Año: 2012 vol. 156 p. 102 - 111

0168-1605

Several methods based on recombinant DNA techniques have been proposed for yeast strain improvement;however, the most relevant oenological traits depend on a multitude of loci, making these techniques difficultto apply. In this way, hybridization techniques involving two complete genomes became interesting. Naturalhybrid strains between different Saccharomyces species have been detected in diverse fermented beveragesincluding wine, cider and beer. These hybrids seem to be better adapted to fluctuating situations typically observedin fermentations due to the acquisition of particular physiological properties of both parental strains.In this work we evaluated the usefulness of three different hybridization methods: spore to spore mating,rare-mating and protoplast fusion for the generation of intra- and inter-specific stable hybrids, being thefirst report about the comparison of different methods to obtain artificial hybrids to be used in fermentations.Spore to spore mating is an easy but time-consuming method; hybrids generated with this technique couldlack some of the industrially relevant traits present in the parental strains because of the segregation occurredduring meiosis and spore generation prior to hybridization. Hybrids obtained by protoplast fusionget the complete information of both parents but they are currently considered as genetically modified organisms(GMOs). Finally, hybrids obtained by rare-mating are easily obtained by the optimized methodologydescribed in this work, they originally contain a complete set of chromosomes of both parents and they arenot considered as GMOs. Hybrids obtained by means of the three methodological approaches showed ahigh genetic variability; however, a loss of genetic material was detected in most of them. Based on these results,it became evident that a last crucial aspect to be considered in every hybridization program is the geneticstabilization of recently generated hybrids that guarantee its invariability during future industrialutilization. In this work, a wine yeast genetic stabilization process was developed and vegetatively stable hybridswere obtained.