Dynamics of the Saccharomyces cerevisiae Transcriptome during Bread Dough Fermentation
Dynamics of the Saccharomyces cerevisiae Transcriptome during Bread Dough Fermentation
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DOI：
10.1128/aem.02649-13
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发表时间：
2013-12-01
影响因子：
4.4
通讯作者：
Verstrepen, Kevin J.
中科院分区：
文献类型：
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作者：
Aslankoohi, Elham;Zhu, Bo;Verstrepen, Kevin J.
酵母细胞在啤酒、葡萄酒和生物乙醇生产等工业过程中的行为已被广泛研究。相比之下，我们对固态过程中酵母生理学的了解，如面包面团，奶酪或可可发酵，仍然有限。我们研究了面包面团发酵过程中三种遗传上不同的酿酒酵母菌株的转录组的变化。我们的研究结果表明，无论遗传背景，所有三个菌株表现出相似的表达模式的变化。在发酵开始时，葡萄糖调节基因的表达发生显著变化，并且渗透胁迫响应被激活。中间发酵阶段的特征在于诱导参与氨基酸代谢的基因。最后，在最后的时间点，细胞遭受营养耗尽并激活与饥饿和应激反应相关的途径。进一步的分析显示，由高渗透压甘油（HOG）途径（参与对渗透胁迫和甘油稳态的响应的主要途径）调节的基因是发酵开始时最差异表达的基因之一。更重要的是，HOG1和该途径的其他基因的缺失显著降低了发酵能力。总之，我们的研究结果表明，嵌入在固体基质，如面包面团的细胞遭受严重的渗透压和HOG途径的适当诱导是最佳发酵的关键。
The behavior of yeast cells during industrial processes such as the production of beer, wine, and bioethanol has been extensively studied. In contrast, our knowledge about yeast physiology during solid-state processes, such as bread dough, cheese, or cocoa fermentation, remains limited. We investigated changes in the transcriptomes of three genetically distinct Saccharomyces cerevisiae strains during bread dough fermentation. Our results show that regardless of the genetic background, all three strains exhibit similar changes in expression patterns. At the onset of fermentation, expression of glucose- regulated genes changes dramatically, and the osmotic stress response is activated. The middle fermentation phase is characterized by the induction of genes involved in amino acid metabolism. Finally, at the latest time point, cells suffer from nutrient depletion and activate pathways associated with starvation and stress responses. Further analysis shows that genes regulated by the high- osmolarity glycerol (HOG) pathway, the major pathway involved in the response to osmotic stress and glycerol homeostasis, are among the most differentially expressed genes at the onset of fermentation. More importantly, deletion of HOG1 and other genes of this pathway significantly reduces the fermentation capacity. Together, our results demonstrate that cells embedded in a solid matrix such as bread dough suffer severe osmotic stress and that a proper induction of the HOG pathway is critical for optimal fermentation.