Department of Genetics, Philipps-Universität Marburg, Marburg, Germany.
Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland.
Elife. 2020 Apr 14;9:e55587. doi: 10.7554/eLife.55587.
Microorganisms have evolved specific cell surface molecules that enable discrimination between cells from the same and from a different kind. Here, we investigate the role of Flo11-type cell surface adhesins from social yeasts in kin discrimination. We measure the adhesion forces mediated by Flo11A-type domains using single-cell force spectroscopy, quantify Flo11A-based cell aggregation in populations and determine the Flo11A-dependent segregation of competing yeast strains in biofilms. We find that Flo11A domains from diverse yeast species confer remarkably strong adhesion forces by establishing homotypic interactions between single cells, leading to efficient cell aggregation and biofilm formation in homogenous populations. Heterotypic interactions between Flo11A domains from different yeast species or strains confer weak adhesive forces and lead to efficient strain segregation in heterogenous populations, indicating that in social yeasts Flo11A-mediated cell adhesion is a major mechanism for kin discrimination at species and sub-species levels. These findings, together with our structure and mutation analysis of selected Flo11A domains, provide a rationale of how cell surface receptors have evolved in microorganisms to mediate kin discrimination.
微生物已经进化出特定的细胞表面分子，使它们能够区分同种细胞和不同种细胞。在这里，我们研究了社交酵母的 Flo11 型细胞表面黏附素在亲缘识别中的作用。我们使用单细胞力谱测量 Flo11A 型结构域介导的黏附力，在群体中定量基于 Flo11A 的细胞聚集，并确定 Flo11A 依赖性竞争酵母菌株在生物膜中的分离。我们发现，来自不同酵母物种的 Flo11A 结构域通过在单细胞之间建立同型相互作用，赋予了非常强的黏附力，从而在同质群体中实现了高效的细胞聚集和生物膜形成。来自不同酵母物种或菌株的 Flo11A 结构域之间的异型相互作用赋予了较弱的黏附力，并导致在异质群体中有效分离菌株，表明在社交酵母中，Flo11A 介导的细胞黏附是在种和亚种水平上进行亲缘识别的主要机制。这些发现，以及我们对选定的 Flo11A 结构域的结构和突变分析，为微生物中细胞表面受体如何进化以介导亲缘识别提供了依据。
