Himalayan Saccharomyces eubayanus Genome Sequences Reveal Genetic Markers Explaining Heterotic Maltotriose Consumption by Saccharomyces pastorianus Hybrids
Himalayan Saccharomyces eubayanus Genome Sequences Reveal Genetic Markers Explaining Heterotic Maltotriose Consumption by Saccharomyces pastorianus Hybrids
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DOI：
10.1128/aem.01516-19
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发表时间：
2019-11-01
影响因子：
4.4
通讯作者：
Daran, Jean-Marc G.
中科院分区：
文献类型：
--
作者：
Brouwers, Nick;Brickwedde, Anja;Daran, Jean-Marc G.
巴斯德酵母菌株是酿酒酵母和真巴亚酵母的杂交种，已经在拉格啤酒酿造环境中驯化了几个世纪。作为序列和结构的S.虽然巴斯德酵母的基因组正在被解析，但几种工业相关表型的分子机制和进化起源仍然未知。本研究探讨麦芽三糖代谢，一个关键特征，在酿造，可能已经出现在早期的S。大叶桉酿酒酵母杂交种为了解决这个问题，我们产生了一个几乎完整的喜马拉雅S。泛北极亚支的eubayanus菌株。这组菌株被认为是S. eubayanus亚基因组的起源。pastorianus菌株。喜马拉雅山S. eubayanus基因组中含有一个S. eubayanus AGT 1（SeAGT 1）α-寡葡糖苷转运蛋白基因与S. pastorianus虽然喜马拉雅山S. eubayanus菌株不能在麦芽糖和麦芽三糖上生长，它们的麦芽糖水解酶和SeMALT 1和SeAGT 1麦芽糖转运蛋白基因与S.啤酒。表达，在喜马拉雅S. eubayanus的功能性S.酿酒酵母麦芽糖代谢调节基因（MALx 3）能够在寡糖苷上生长。麦芽三糖阳性表型的假设，在S。通过构建S.酿酒酵母× S. eubayanus实验室杂交种，其麦芽糖代谢基因的互补与目前的S. pastorianus菌株。这种杂交体消耗啤酒麦芽汁中麦芽三糖的能力证明了亚基因组之间的调控串扰，从而验证了这一假设。这些结果支持实验上的一个重要的表型的啤酒酿造菌株和有价值的知识，为工业开发实验室制造的S.重要性S. pastorianus，和S.酿酒酵母× S. Eubayanus hybrid用于生产拉格啤酒，这是世界上生产最多的酒精饮料。它出现了自发杂交和殖民早期啤酒酿造过程。尽管积累和分析了S.虽然巴斯德酵母亲本基因组的遗传图谱与工业相关表型的遗传图谱相似，但仍未得到解决。麦芽三糖是麦芽汁中含量丰富的一种糖，它的同化作用被认为是遗传自S。酿酒酵母亲本在这里，我们证明，虽然亚洲S。eubayanus分离物具有功能性麦芽三糖转运蛋白SeAGT 1基因，它们不能在α-寡糖苷上生长，但S.酿酒酵母调节子MAL 13（ScMAL 13）足以恢复在三代的生长。我们假设S.巴斯德酵母麦芽三糖表型的结果之间的相互作用的调节S。酿酒酵母麦芽糖转录激活因子和SeAGT 1的启动子。我们通过实验证实了表型的杂种优势性质，因此这些结果提供了实验证据的一个重要的表型的啤酒酿造菌株的进化起源。
Saccharomyces pastorianus strains are hybrids of Saccharomyces cerevisiae and Saccharomyces eubayanus that have been domesticated for centuries in lager beer brewing environments. As sequences and structures of S. pastorianus genomes are being resolved, molecular mechanisms and evolutionary origins of several industrially relevant phenotypes remain unknown. This study investigates how maltotriose metabolism, a key feature in brewing, may have arisen in early S. eubayanus X S. cerevisiae hybrids. To address this question, we generated a nearly complete genome assembly of Himalayan S. eubayanus strains of the Holarctic subclade. This group of strains has been proposed to be the S. eubayanus subgenome origin of current S. pastorianus strains. The Himalayan S. eubayanus genomes harbored several copies of an S. eubayanus AGT1 (SeAGT1) alpha-oligoglucoside transporter gene with high sequence identity to genes encountered in S. pastorianus. Although Himalayan S. eubayanus strains cannot grow on maltose and maltotriose, their maltose-hydrolase and SeMALT1 and SeAGT1 maltose transporter genes complemented the corresponding null mutants of S. cerevisiae. Expression, in Himalayan S. eubayanus of a functional S. cerevisiae maltose metabolism regulator gene (MALx3) enabled growth on oligoglucosides. The hypothesis that the maltotriose-positive phenotype in S. pastorianus is a result of heterosis was experimentally tested by constructing an S. cerevisiae x S. eubayanus laboratory hybrid with a complement of maltose metabolism genes that resembles that of current S. pastorianus strains. The ability of this hybrid to consume maltotriose in brewer's wort demonstrated regulatory cross talk between subgenomes and thereby validated this hypothesis. These results support experimentally the new postulated hypothesis on the evolutionary origin of an essential phenotype of lager brewing strains and valuable knowledge for industrial exploitation of laboratory-made S. pastorianus-like hybrids.IMPORTANCE S. pastorianus, an S. cerevisiae x S. eubayanus hybrid, is used for production of lager beer, the most produced alcoholic beverage worldwide. It emerged by spontaneous hybridization and colonized early lager brewing processes. Despite accumulation and analysis of genome sequencing data of S. pastorianus parental genomes, the genetic blueprint of industrially relevant phenotypes remains unresolved. Assimilation of maltotriose, an abundant sugar in wort, has been postulated to be inherited from the S. cerevisiae parent. Here, we demonstrate that although Asian S. eubayanus isolates harbor a functional maltotriose transporter SeAGT1 gene, they are unable to grow on a-oligoglucosides, but expression of S. cerevisiae regulator MAL13 (ScMAL13) was sufficient to restore growth on trisaccharides. We hypothesized that the S. pastorianus maltotriose phenotype results from regulatory interaction between S. cerevisiae maltose transcription activator and the promoter of SeAGT1. We experimentally confirmed the heterotic nature of the phenotype, and thus these results provide experimental evidence of the evolutionary origin of an essential phenotype of lager brewing strains.