Silver is a non‐essential metal used in medical applications as an antimicrobial agent, but it is also toxic for biological systems. To investigate the molecular basis of silver resistance in yeast, we employed evolutionary engineering using successive batch cultures at gradually increased silver stress levels up to 0.25‐mM AgNO₃ in 29 populations and obtained highly silver‐resistant and genetically stable Saccharomyces cerevisiae strains. Cross‐resistance analysis results indicated that the silver‐resistant mutants also gained resistance against copper and oxidative stress. Growth physiological analysis results revealed that the highly silver‐resistant evolved strain 2E was not significantly inhibited by silver stress, unlike the reference strain. Genomic and transcriptomic analysis results revealed that there were mutations and/or significant changes in the expression levels of the genes involved in cell wall integrity, cellular respiration, oxidative metabolism, copper homeostasis, endocytosis and vesicular transport activities. Particularly the missense mutation in the RLM1 gene encoding a transcription factor involved in the maintenance of cell wall integrity and with 707 potential gene targets might have a key role in the high silver resistance of 2E, along with its improved cell wall integrity, as confirmed by the lyticase sensitivity assay results. In conclusion, the comparative physiological, transcriptomic and genomic analysis results of the silver‐resistant S. cerevisiae strain revealed potential key factors that will help understand the complex molecular mechanisms of silver resistance in yeast.

中文翻译：

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通过进化工程获得的耐银酿酒酵母的基因组、转录组和生理分析

银是一种在医疗应用中用作抗菌剂的非必需金属，但它对生物系统也有毒。为了研究酵母银抗性的分子基础，我们采用进化工程，使用连续分批培养，在 29 个种群中逐步增加银胁迫水平至 0.25 mM AgNO ₃，并获得高度抗银和遗传稳定的酿酒酵母菌株。交叉抗性分析结果表明，银抗性突变体也获得了对铜和氧化应激的抗性。生长生理分析结果表明，与参考菌株不同，高度抗银进化菌株 2E 不受银胁迫的显着抑制。基因组和转录组分析结果显示，涉及细胞壁完整性、细胞呼吸、氧化代谢、铜稳态、内吞作用和囊泡转运活动的基因的表达水平存在突变和/或显着变化。特别是RLM1 中的错义突变正如裂解酶敏感性测定结果所证实的那样，编码参与维持细胞壁完整性并具有 707 个潜在基因靶标的转录因子的基因可能在 2E 的高抗银性及其改善的细胞壁完整性中起关键作用。总之，抗银酿酒酵母菌株的生理学、转录组学和基因组分析结果揭示了潜在的关键因素，有助于理解酵母抗银的复杂分子机制。