Most cells spend the majority of their life in the non‐proliferating, quiescent state. Transition to this state is crucial for microorganisms to survive long starvation periods and restart divisions afterwards. Experimental evolution allowed us to identify several mutation in genes that are presumably important for such transition in yeast cells. Most of these candidate genes belong to the SPS amino acid sensing pathway or to the SIR complex. We assembled these mutations on the ancestral strain background. Analysis of the quiescent/non‐quiescent cell ratio of the starved yeast populations confirmed the crucial role of SSY1, the primary receptor component of the SPS sensor, in transition to the Q state. The evolved SSY1 mutations increased yeast sensitivity to amino acid presence in the environment. This resulted in decreased quiescent cell fraction and a 5.14% increase of the total amino acid content in the starved populations. We discuss external amino acid sensing via the SPS pathway as one of the mechanisms influencing transition to quiescence.

中文翻译：

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超敏 SSY1 突变对酵母酿酒酵母向静止的过渡产生负面影响

大多数细胞一生中的大部分时间都处于非增殖、静止状态。过渡到这种状态对于微生物在长期饥饿期间存活并在之后重新开始分裂至关重要。实验进化使我们能够识别出几种可能对酵母细胞中的这种转变很重要的基因突变。这些候选基因中的大多数属于 SPS 氨基酸传感途径或 SIR 复合物。我们在祖先菌株背景上组装了这些突变。对饥饿酵母种群的静止/非静止细胞比率的分析证实了SSY1（SPS 传感器的主要受体成分）在向 Q 状态转变过程中的关键作用。进化的SSY1突变增加了酵母对环境中氨基酸存在的敏感性。这导致静止细胞分数减少，饥饿群体中总氨基酸含量增加 5.14%。我们将通过 SPS 途径的外部氨基酸感应作为影响过渡到静止的机制之一进行讨论。