Despite the intensive use of selected wine yeasts, there is still a margin for technological improvement. Previous studies on yeast genetics have shown that many of their characters, which determine the quality of wines, have a genetic basis and are susceptible to manipulation.
This work addresses the genetic improvement of a high-sulphurous-producer yeast using a method for homothallic wine yeast based on spore hybridization that allows easy hybrid selection and identification.
The method takes advantage of the fact that the killer phenotype is very frequent among wine yeasts.
Firstly, two spontaneous mutants highly homozygous and free from growth-retarding alleles (Mutant-24 and -25), which contains easily detectable genetic markers (cycloheximide-resistant or CYHR), were obtained from a sensitive (non-killer or K-) high-sulphurous-producer homothallic yeast (the original yeast). The homozygous Mutant-24 and -25 spores were crossed with killer low-sulphurous-producer wine yeasts to obtain killer (type K2 or Klus) and low-sulphurous producer hybrids. A yeast micromanipulator was used to mix 4 (K- CYHR, high-sulphurous-producer) × 4 (K+ CYHS, low-sulphurous-producer) spores as previously described (1).
Initially, many low-sulphurous-producer hybrids K+ CYHR were obtained, all of them with a good fermentative capacity in synthetic must with respect to the original yeast. This result suggests that this method for homothallic yeast hybridization is very useful for industrial yeast improvement.
Keywords: genetic improvement, hybridazion, yeast, high-sulphurous producer, wine.
Article based on the poster presented at the at the 12th edition of Enoforum (Vicenza, Italy, May 21-23, 2019).