Aneuploidy and Ethanol Tolerance in Saccharomyces cerevisiae
Aneuploidy and Ethanol Tolerance in Saccharomyces cerevisiae
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DOI：
10.3389/fgene.2019.00082
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发表时间：
2019-02-12
影响因子：
3.7
通讯作者：
Barrio, Eladio
中科院分区：
文献类型：
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作者：
Morard, Miguel;Macias, Laura G.;Barrio, Eladio
对环境胁迫的响应是微生物生长的关键因素。酵母在发酵环境中的主要压力之一是乙醇。酿酒酵母（Saccharomyces cerevisiae）是该属中最耐酒精的菌种，但种内存在耐酒精性变异。虽然，在过去的几年里，已经做了很多努力来发现进化路径，以提高乙醇耐受性，这种表型仍然很难理解。在这里，我们选择了五个具有不同乙醇耐受性的菌株，并使用比较基因组学来确定可以解释这些表型差异的主要因素。令人惊讶的是，主要的基因组特征，只有最高的乙醇耐受菌株共享，是一个多体染色体III。转录组学数据指出，染色体III对于乙醇胁迫反应是重要的，并且这种非整倍性可以是对乙醇胁迫快速响应的优势。我们发现，染色体III拷贝数也解释了其他菌株的差异。我们表明，在乙醇耐受菌株中去除额外的染色体III拷贝，恢复整倍性，强烈损害其耐受性。染色体III非整倍体经常出现在乙醇耐受性进化实验中，在这里，我们表明非整倍体也被自然菌株用来提高其乙醇耐受性。
Response to environmental stresses is a key factor for microbial organism growth. One of the major stresses for yeasts in fermentative environments is ethanol. Saccharomyces cerevisiae is the most tolerant species in its genus, but intraspecific ethanol-tolerance variation exists. Although, much effort has been done in the last years to discover evolutionary paths to improve ethanol tolerance, this phenotype is still hardly understood. Here, we selected five strains with different ethanol tolerances, and used comparative genomics to determine the main factors that can explain these phenotypic differences. Surprisingly, the main genomic feature, shared only by the highest ethanol-tolerant strains, was a polysomic chromosome III. Transcriptomic data point out that chromosome III is important for the ethanol stress response, and this aneuploidy can be an advantage to respond rapidly to ethanol stress. We found that chromosome III copy numbers also explain differences in other strains. We show that removing the extra chromosome III copy in an ethanol-tolerant strain, returning to euploidy, strongly compromises its tolerance. Chromosome III aneuploidy appears frequently in ethanol-tolerance evolution experiments, and here, we show that aneuploidy is also used by natural strains to enhance their ethanol tolerance.