Distinct Domestication Trajectories in Top-Fermenting Beer Yeasts and Wine Yeasts
Distinct Domestication Trajectories in Top-Fermenting Beer Yeasts and Wine Yeasts
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DOI：
10.1016/j.cub.2016.08.040
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发表时间：
2016-10-24
期刊：
影响因子：
9.2
通讯作者：
Sampaio, Jose Paulo
中科院分区：
文献类型：
--
作者：
Goncalves, Margarida;Pontes, Ana;Sampaio, Jose Paulo
啤酒是最古老的酒精饮料之一，由谷物中的淀粉中提取的糖发酵而成。大啤酒是由一种混合酵母——巴斯德酵母（Saccharomyces pastorianus）的底部发酵菌株酿造的，与之相反，麦芽啤酒更接近古老的啤酒类型，由一种顶部发酵酵母酿酒酵母（S. cerevisiae）发酵。在这里，我们使用群体基因组学来研究(1)上发酵啤酒酵母的近亲；(2)顶发酵菌是否代表一个独立的驯化事件，与已经描述的驯化事件分开；(3)是否可以推断出单个或多个啤酒酵母驯化事件；(4)顶发酵菌是否代表非重组或重组谱系。我们的研究结果表明，顶发酵啤酒酵母具有多系性，其主进化枝至少由三个亚群组成，以德国、英国和小麦啤酒菌株为主要代表。其他啤酒菌株在系统发育上与清酒、葡萄酒或面包酵母接近。我们通过研究先前与酿造相关的基因并使用全基因组扫描来检测啤酒酵母驯化的遗传特征。我们提出，啤酒酵母的主要分支的出现与驯化事件不同于以前已知的葡萄酒和清酒酵母驯化的情况有关。主要啤酒酵母的核苷酸多样性是葡萄酒酵母的两倍多，这可能是啤酒和葡萄酒酵母驯化模式的根本差异的结果。啤酒品种的多样性可能是由于与酿造相关的更激烈和不同的选择制度。
Beer is one of the oldest alcoholic beverages and is produced by the fermentation of sugars derived from starches present in cereal grains. Contrary to lager beers, made by bottom-fermenting strains of Saccharomyces pastorianus, a hybrid yeast, ale beers are closer to the ancient beer type and are fermented by S. cerevisiae, a top-fermenting yeast. Here, we use population genomics to investigate (1) the closest relatives of top-fermenting beer yeasts; (2) whether top-fermenting yeasts represent an independent domestication event separate from those already described; (3) whether single or multiple beer yeast domestication events can be inferred; and (4) whether top-fermenting yeasts represent non-recombinant or recombinant lineages. Our results revealed that top-fermenting beer yeasts are polyphyletic, with a main clade composed of at least three subgroups, dominantly represented by the German, British, and wheat beer strains. Other beer strains were phylogenetically close to sake, wine, or bread yeasts. We detected genetic signatures of beer yeast domestication by investigating genes previously linked to brewing and using genome-wide scans. We propose that the emergence of the main clade of beer yeasts is related with a domestication event distinct from the previously known cases of wine and sake yeast domestication. The nucleotide diversity of the main beer Glade more than doubled that of wine yeasts, which might be a consequence of fundamental differences in the modes of beer and wine yeast domestication. The higher diversity of beer strains could be due to the more intense and different selection regimes associated to brewing.