Fungi have developed the ability to overcome extreme growth conditions and thrive in hostile environments. The model fungus Aspergillus nidulans tolerates, for example, ambient alkalinity up to pH 10 or molar concentrations of multiple cations. The ability to grow under alkaline pH or saline stress depends on the effective function of at least three regulatory pathways mediated by the zinc-finger transcription factor PacC, which mediates the ambient pH regulatory pathway, the calcineurin-dependent CrzA and the cation homeostasis responsive factor SltA. Using RNA sequencing, we determined the effect of external pH alkalinization or sodium stress on gene expression. The data show that each condition triggers transcriptional responses with a low degree of overlap. By sequencing the transcriptomes of the null mutant, the role of SltA in the above-mentioned homeostasis mechanisms was also studied. The results show that the transcriptional role of SltA is wider than initially expected and implies, for example, the positive control of the PacC-dependent ambient pH regulatory pathway. Overall, our data strongly suggest that the stress response pathways in fungi include some common but mostly exclusive constituents, and that there is a hierarchical relationship among the main regulators of stress response, with SltA controlling pacC expression, at least in A. nidulans.

中文翻译：

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定义构巢曲霉对阳离子/碱性 pH 胁迫的转录反应以及转录因子 SltA 的作用。


真菌已经具备了克服极端生长条件并在恶劣环境中茁壮成长的能力。例如，模型真菌构巢曲霉可以耐受高达 pH 10 的环境碱度或多种阳离子的摩尔浓度。在碱性 pH 或盐胁迫下生长的能力取决于至少由锌指转录因子 PacC 介导的三个调节途径的有效功能，PacC 介导环境 pH 调节途径、钙调神经磷酸酶依赖性 CrzA 和阳离子稳态响应因子斯尔特A。通过 RNA 测序，我们确定了外部 pH 碱化或钠胁迫对基因表达的影响。数据显示，每种情况都会触发转录反应，且重叠程度较低。通过对无效突变体的转录组进行测序，还研究了SltA在上述稳态机制中的作用。结果表明，SltA 的转录作用比最初预期的更广泛，并且意味着，例如，对 PacC 依赖性环境 pH 调节途径的正控制。总的来说，我们的数据强烈表明真菌中的应激反应途径包括一些常见但大多是排他性的成分，并且应激反应的主要调节因子之间存在层次关系，其中SltA控制pacC表达，至少在构巢曲霉中是这样。