During industrial processes, yeasts are exposed to harsh conditions, which eventually lead to adaptation of the strains. In the laboratory, it is possible to use experimental evolution to link the evolutionary biology response to these adaptation pressures for the industrial improvement of a specific yeast strain. In this work, we aimed to study the adaptation of a wine industrial yeast in stress conditions of the high ethanol concentrations present in stopped fermentations and secondary fermentations in the processes of champagne production. We used a commercial Saccharomyces cerevisiae × S. uvarum hybrid and assessed its adaptation in a modified synthetic must (M-SM) containing high ethanol, which also contained metabisulfite, a preservative that is used during wine fermentation as it converts to sulfite. After the adaptation process under these selected stressful environmental conditions, the tolerance of the adapted strain (H14A7-etoh) to sulfite and ethanol was investigated, revealing that the adapted hybrid is more resistant to sulfite compared to the original H14A7 strain, whereas ethanol tolerance improvement was slight. However, a trade-off in the adapted hybrid was found, as it had a lower capacity to ferment glucose and fructose in comparison with H14A7. Hybrid genomes are almost always unstable, and different signals of adaptation on H14A7-etoh genome were detected. Each subgenome present in the adapted strain had adapted differently. Chromosome aneuploidies were present in S. cerevisiae chromosome III and in S. uvarum chromosome VII–XVI, which had been duplicated. Moreover, S. uvarum chromosome I was not present in H14A7-etoh and a loss of heterozygosity (LOH) event arose on S. cerevisiae chromosome I. RNA-sequencing analysis showed differential gene expression between H14A7-etoh and H14A7, which can be easily correlated with the signals of adaptation that were found on the H14A7-etoh genome. Finally, we report alterations in the lipid composition of the membrane, consistent with conserved tolerance mechanisms.

中文翻译：

---

对葡萄酒选择压力的适应性反应塑造了酵母菌种间杂种的基因组

在工业过程中，酵母暴露在恶劣的条件下，最终导致菌株适应。在实验室中，可以使用实验进化将进化生物学反应与这些适应压力联系起来，以实现特定酵母菌株的工业改进。在这项工作中，我们旨在研究葡萄酒工业酵母在香槟生产过程中停止发酵和二次发酵中存在的高乙醇浓度的压力条件下的适应性。我们使用了商业酿酒酵母 × S. uvarum混合并评估了其在含有高乙醇的改性合成葡萄汁（M-SM）中的适应性，其中还含有焦亚硫酸盐，这是一种在葡萄酒发酵过程中转化为亚硫酸盐时使用的防腐剂。在这些选定的压力环境条件下适应过程后，研究了适应菌株 (H14A7-etoh) 对亚硫酸盐和乙醇的耐受性，结果表明，与原始 H14A7 菌株相比，适应的杂种对亚硫酸盐的抵抗力更强，而乙醇耐受性提高很轻微。然而，发现了适应杂交种的权衡，因为与 H14A7 相比，它发酵葡萄糖和果糖的能力较低。杂交基因组几乎总是不稳定的，并且在 H14A7-etoh 基因组上检测到不同的适应信号。适应菌株中存在的每个亚基因组都有不同的适应。染色体非整倍体存在于S. cerevisiae染色体 III 和S. uvarum染色体 VII-XVI，已被复制。此外，葡萄球菌I 号染色体在 H14A7-etoh 中不存在，并且在酿酒酵母I 号染色体上出现杂合性丢失 (LOH) 事件。RNA 测序分析显示 H14A7-etoh 和 H14A7 之间的基因表达差异，这很容易与在 H14A7-etoh 基因组上发现的适应信号相关。最后，我们报告了膜脂质组成的变化，与保守的耐受机制一致。