Competition experiments betweenBrettanomyces bruxellensisstrains reveal specific adaptation to sulfur dioxide and complex interactions at intraspecies level

Abstract

Recent studies have suggested a strong niche adaptation for Brettanomyces bruxellensis strains according to human-related fermentation environments, including beer, wine and bioethanol. This is further supported by a correlation between B. bruxellensis genetic grouping and tolerance to SO2, the main antimicrobial used in wine. The allotriploid AWRI1499-like cluster, in particular, shows high SO2 tolerance suggesting that the genetic configuration observed for these strains may confer a selective advantage in winemaking conditions. To test this hypothesis, we evaluated the relative selective advantage of representatives of the three main B. bruxellensis genetic groups in presence of SO2. As a proof-of-concept and using recently developed transformation cassettes, we compared strains under different SO2 concentrations using pairwise competitive fitness experiments. Our results showed that AWRI1499 is specifically adapted to environments with high SO2 concentrations compared to other B. bruxellensis wine strains, indicating a potential correlation between allotriploidisation origin and environmental adaptation in this species. Additionally, our findings suggest different types of competition between strains, such as coexistence and exclusion, revealing new insights on B. bruxellensis interactions at intraspecies level.

Brettanomyces bruxellensis wine isolates show high geographical dispersal and long remanence in cellars

“…Winemaking environments may have supported the existence of specific selective pressure favouring the retaining of fitter allotriploid individuals and their progressive proliferation in the last decades. Indeed, competition experiments between tolerant and sensitive strains showed that the former outcompeted the latter in high SO 2 concentrations [41]. Altogether, our results suggest that independent allotriploidisation events in B. bruxellensis may have allowed diversification and subsequent adaptation to winemaking practices.…”

“…The strains were clustered in 6 genetic groups, depending on both their ploidy level (diploid versus triploid) and their substrate of isolation [38]. Besides their genetic difference, these populations presented contrasted phenotypes: two different groups of triploid strains, mostly associated with wine substrate, showed tolerance or resistance to sulfur dioxide, the most common preservative used in winemaking [39–41]. A preliminary study on a small subset of 8 strains suggested variability in bioadhesion and colonization properties [42].…”

Biodiversity among Brettanomyces bruxellensis Strains Isolated from Different Wine Regions of Chile: Key Factors Revealed about Its Tolerance to Sulphite

“…However, this cannot apply to processes contaminated with L-2676 or L-2679 clonal groups. The existence of allotriploidy and genotype diversity in B. bruxellensis has been linked to high tolerance to SO 2 [31][32][33][34][35][36][37][38], and has been attributed to the selection that occurs when adding this antimicrobial to the wide range of fermented beverages. If allotriploidy is the key factor in these two strains, this is a matter that requires further investigation.…”

Formation of Aromatic and Flavor Compounds in Wine: A Perspective of Positive and Negative Contributions of Non-SaccharomycesYeasts

“…Also, karyotypic studies suggest speciation due to genome rearrangements. However, available genetic studies are of a limited number of strains [121,[126][127][128][129][130]. In this regard, a transcriptomic analysis of the strain of B. bruxellensis LAMAP2480 exposed to p-coumaric acid indicates that this acid generates a stress condition, inducing the expression of the proton pump together with the output of toxic compounds, as well as the output of nitrogen compounds, reducing intracellular concentration and triggering the expression of nitrogen metabolism genes (Figure 3) [121].…”