ABSTRACT

Many yeasts differentiate into multicellular phenotypes in adverse environmental conditions. Here, we investigate pseudohyphal growth in Komagataella phaffii and the involvement of the flocculin (FLO) gene family in its regulation. The K. phaffii FLO family consists of 13 members, and the conditions inducing pseudohyphal growth are different from Saccharomyces cerevisiae. So far, this phenotype was only observed when K. phaffii was cultivated at slow growth rates in glucose-limited chemostats, but not upon nitrogen starvation or the presence of fusel alcohols. Transcriptional analysis identified that FLO11, FLO400 and FLO5-1 are involved in the phenotype, all being controlled by the transcriptional regulator Flo8. The three genes exhibit a complex mechanism of expression and repression during transition from yeast to pseudohyphal form. Unlike in S. cerevisiae, deletion of FLO11 does not completely prevent the phenotype. In contrast, deletion of FLO400 or FLO5-1 prevents pseudohyphae formation, and hampers FLO11 expression. FAIRE-Seq data shows that the expression and repression of FLO400 and FLO5-1 are correlated to open or closed chromatin regions upstream of these genes, respectively. Our findings indicate that K. phaffii Flo400 and/or Flo5-1 act as upstream signals that lead to the induction of FLO11 upon glucose limitation in chemostats at slow growth and chromatin modulation is involved in the regulation of their expression.

中文翻译：

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Komagataella phaffii 的假菌丝分化：调查 FLO 基因家族。

摘要

许多酵母在不利的环境条件下分化成多细胞表型。在这里，我们调查了Komagataella phaffii中的假菌丝生长以及 floclin ( FLO ) 基因家族在其调控中的作用。K. phaffii FLO家族由13个成员组成，诱导假菌丝生长的条件与Saccharomyces cerevisiae不同。到目前为止，这种表型仅在K. phaffii在葡萄糖限制的恒化器中以缓慢生长速率培养时观察到，而不是在氮饥饿或杂醇存在时观察到。转录分析确定了FLO11、FLO400和FLO5-1参与表型，均受转录调节因子 Flo8 控制。这三个基因在从酵母到假菌丝形式的转变过程中表现出复杂的表达和抑制机制。与酿酒酵母不同，FLO11的缺失并不能完全阻止该表型。相反，FLO400或FLO5-1的缺失可防止假菌丝形成，并阻碍FLO11 的表达。FAIRE-Seq 数据显示FLO400和FLO5-1的表达和抑制分别与这些基因上游的开放或封闭染色质区域相关。我们的研究结果表明，K. phaffiiFlo400 和/或 Flo5-1 充当上游信号，导致在缓慢生长的恒化器中葡萄糖限制时诱导FLO11，并且染色质调节参与其表达的调节。