Data from: QTL mapping of volatile compound production in Saccharomyces cerevisiae during alcoholic fermentation

Background: The volatile metabolites produced by Saccharomyces cerevisiae during alcoholic fermentation, which are mainly esters, higher alcohols and organic acids, play a vital role in the quality and perception of fermented beverages, such as wine. Although the metabolic pathways and genes behind yeast fermentative aroma formation are well described, little is known about the genetic mechanisms underlying variations between strains in the production of these aroma compounds. To increase our knowledge about the links between genetic variation and volatile production, we performed quantitative trait locus (QTL) mapping using 130 F2-meiotic segregants from two S. cerevisiae wine strains. The segregants were individually genotyped by next-generation sequencing and separately phenotyped during wine fermentation.
Results: Using different QTL mapping strategies, we were able to identify 65 QTLs in the genome, including 55 that influence the formation of 30 volatile secondary metabolites, 14 with an effect on sugar consumption and central carbon metabolite production, and 7 influencing fermentation parameters. For ethyl lactate, ethyl octanoate and propanol formation, we discovered 2 interacting QTLs each. Within 9 of the detected regions, we validated the contribution of 13 genes in the observed phenotypic variation by reciprocal hemizygosity analysis. These genes are involved in nitrogen uptake and metabolism (AGP1, ALP1, ILV6, LEU9), central carbon metabolism (HXT3, MAE1), fatty acid synthesis (FAS1) and regulation (AGP2, IXR1, NRG1, RGS2, RGT1, SIR2) and explain variations in the production of characteristic sensorial esters (e.g., 2-phenylethyl acetate, 2-metyhlpropyl acetate and ethyl hexanoate), higher alcohols and fatty acids.
Conclusions: The detection of QTLs and their 51 interactions emphasizes the complexity of yeast fermentative aroma formation. The validation of underlying allelic variants increases knowledge about genetic variation impacting metabolic pathways that lead to the synthesis of sensorial important compounds. As a result, this work lays the foundation for tailoring S. cerevisiae strains with optimized volatile metabolite production for fermented beverages and other biotechnological applications.

研究背景：酿酒酵母（Saccharomyces cerevisiae）在酒精发酵过程中产生的挥发性代谢物主要包括酯类、高级醇与有机酸，其对葡萄酒等发酵饮品的品质与感官特征具有至关重要的作用。尽管学界已对酵母发酵香气形成相关的代谢通路与基因进行了充分阐释，但对于不同菌株间此类香气化合物产量差异的遗传机制仍知之甚少。为深入解析遗传变异与挥发性代谢物生成之间的关联，本研究以两株酿酒酵母葡萄酒菌株的130个F₂减数分裂分离株为材料，开展数量性状位点（quantitative trait locus, QTL）定位分析。通过下一代测序（next-generation sequencing）对分离株进行单独基因分型，并在葡萄酒发酵条件下分别完成表型鉴定。
研究结果：借助多种QTL定位策略，我们在基因组中成功鉴定出65个QTL，其中55个与30种挥发性次生代谢物的生成相关，14个影响糖分消耗与中心碳代谢物的产生，另有7个与发酵参数相关。针对乳酸乙酯、辛酸乙酯与丙醇的合成，我们分别发现了2个存在互作的QTL。在检测到的9个基因组区域内，通过反向半合子分析（reciprocal hemizygosity analysis）验证了13个基因对表型变异的贡献。这些基因涉及氮摄取与代谢（AGP1、ALP1、ILV6、LEU9）、中心碳代谢（HXT3、MAE1）、脂肪酸合成（FAS1）以及基因调控（AGP2、IXR1、NRG1、RGS2、RGT1、SIR2），可解释特征性感官酯类（如乙酸苯乙酯、乙酸2-甲基丙酯、己酸乙酯）、高级醇与脂肪酸的产量变异。
研究结论：本研究鉴定的QTL及其51个互作关系凸显了酵母发酵香气形成过程的复杂性。对相关等位基因变异的验证，增进了我们对影响代谢通路遗传变异的认知，而这些代谢通路正是感官重要化合物的合成基础。综上，本研究为培育可优化挥发性代谢物产量的酿酒酵母菌株奠定了基础，可应用于发酵饮品生产及其他生物技术场景。