The impact ofCUP1gene copy-number and XVI-VIII/XV-XVI translocations on copper and sulfite tolerance in vineyardSaccharomyces cerevisiaestrain populations

Abstract

In wine production, sulfites are widely used as antimicrobials and antioxidants, whereas copper is associated with fungicides and wine fining treatments. Therefore, wine yeasts are constantly exposed to these agents. Copper tolerance is related to the copy number of the CUP1 gene, encoding for a metallothionein involved in copper detoxification. In wine yeasts, sulfite resistance mainly depends on the presence of the translocation t(XVI;VIII) in the promoter region of the SSU1 gene. This gene encodes for a plasma membrane sulfite pump involved in sulfite metabolism and detoxification. Recently, a new translocation, t(XVI;VIII), was identified. In this work, 253 Saccharomyces cerevisiae strains, representing three vineyard populations from two different continents, were analyzed, along with 20 industrial starters. Copper and sulfites tolerance as well as distribution of CUP1 gene copy-number, t(XVI;VIII)and t(XVI;XV) of SSU1 gene were studied to evaluate the impact of these genomic variations on population phenotypes. The CUP1 gene copy-number was found to be highly variable, ranging from zero to 79 per strain. Moreover it differently impacted the copper tolerance in the populations of the two continents. The diffusion of t(XVI;VIII) and, for the first time, t(XVI;XV) was determined in the three vineyard populations. The correlation between the presence of the translocation and strain sulfite tolerance levels was significant only for the t(XVI;VIII).

Yeast Metabolism and Its Exploitation in Emerging Winemaking Trends: From Sulfite Tolerance to Sulfite Reduction

“…The VIII-t-XVI was found in 69% of the strains, while the XV-t-XVI was present in 13%. The industrial group had the highest number of strains (80%) carrying the translocation VIII-t-XVI, which was also widespread through the vineyard populations, as 68.4% of the remaining strains carried it [71]. These results also demonstrated for the first time the diffusion of the XV-t-XVI among vineyard strains, although at a low level (13.4%), probably due to a recent translocation event.…”

“…Interesting results arise from a recent study about the impact of XVI-VIII/XV-XVI translocations on copper and sulfite tolerance in vineyard Saccharomyces cerevisiae strain populations [71] (253 strains representing three vineyard-populations from two different countries and 20 industrial starters). Firstly, the results of this work surprisingly evidenced that the levels of SO 2 tolerance in vineyard strains were comparable or higher than those in industrial strains.…”

Engineered yeast genomes accurately assembled from pure and mixed samples

“…However, the CUP1 and rDNA repeat copy numbers were underrepresented in both our assemblies and the reference assemblies when compared to the approximate copy number of the raw Nanopore and Illumina reads. The S. cerevisiaeCUP1 copy number is highly variable, ranging from zero to 79 97 , while the rDNA copy number is known to range between 100 and 200 98 . Tandem repeats such as CUP1 and rDNA are a common problem for all de novo assemblers and are often collapsed during assembly 99 .…”

Natural Saccharomyces cerevisiae Strain Reveals Peculiar Genomic Traits for Starch-to-Bioethanol Production: the Design of an Amylolytic Consolidated Bioprocessing Yeast

“…Most of the L20 chromosomes assembled entirely in one contig except for chromosomes XII and XIV, which assembled in two fragments. The alignments in Figure 3 highlights a significant translocation between chromosomes VIII and XVI, which is a widespread translocation among enological yeast strains, although it has been identified in non-wine strains in the past as well (Perez-Ortin et al, 2002;Hou et al, 2014;Treu et al, 2014;García-Ríos and Guillamón, 2019;Crosato et al, 2020;Basile et al, 2021). It was correlated to an increased sulfur dioxide resistance, which is a critical parameter in winemaking.…”