Institute for Wine Biotechnology, Stellenbosch, South Africa
Department of Viticulture and Oenology, Stellenbosch University, Matieland, South Africa.
mSphere. 2018 Oct 24;3(5):e00383-18. doi: 10.1128/mSphere.00383-18.
Physical contact between yeast species, in addition to better-understood and reported metabolic interactions, has recently been proposed to significantly impact the relative fitness of these species in cocultures. Such data have been generated by using membrane bioreactors, which physically separate two yeast species. However, doubts persist about the degree that the various membrane systems allow for continuous and complete metabolic contact, including the exchange of proteins. Here, we provide independent evidence for the importance of physical contact by using a genetic system to modify the degree of physical contact and, therefore, the degree of asexual intraspecies and interspecies adhesion in yeast. Such adhesion is controlled by a family of structurally related cell wall proteins encoded by the gene family. As previously shown, the expression of specific members of the gene family in dramatically changes the coadhesion patterns between this yeast and other yeast species. Here, we use this differential aggregation mediated by genes as a model to assess the impact of physical contact between different yeast species on the relative fitness of these species in simplified ecosystems. The identity of the gene has a marked effect on the persistence of specific non- yeasts over the course of extended growth periods in batch cultures. Remarkably, and expression often result in opposite outcomes. The data provide clear evidence for the role of physical contact in multispecies yeast ecosystems and suggest that gene expression may be a major factor in such interactions. The impact of direct (physical) versus indirect (metabolic) interactions between different yeast species has attracted significant research interest in recent years. This is due to the growing interest in the use of multispecies consortia in bioprocesses of industrial relevance and the relevance of interspecies interactions in establishing stable synthetic ecosystems. Compartment bioreactors have traditionally been used in this regard but suffer from numerous limitations. Here, we provide independent evidence for the importance of physical contact by using a genetic system, based on the gene family, to modify the degree of physical contact and, therefore, the degree of asexual intraspecies and interspecies adhesion in yeast. Our results show that interspecies contact significantly impacts population dynamics and the survival of individual species. Remarkably, different members of the gene family often lead to very different population outcomes, further suggesting that gene expression may be a major factor in such interactions.
除了更好理解和报道的代谢相互作用之外，最近还提出了酵母种间的物理接触会显著影响这些种在共培养物中的相对适应性。此类数据是通过使用膜生物反应器产生的，该反应器将两种酵母物种物理分离。然而，对于各种膜系统允许连续和完全代谢接触的程度，包括蛋白质的交换，仍然存在疑问。在这里，我们通过使用遗传系统来改变物理接触的程度，从而改变酵母种内和种间无性黏附的程度，提供了物理接触重要性的独立证据。这种黏附是由基因家族编码的结构相关细胞壁蛋白家族控制的。如前所述，基因家族的特定成员的表达在很大程度上改变了这种酵母与其他酵母物种之间的共黏附模式。在这里，我们使用基因差异聚集作为模型，评估不同酵母种间的物理接触对这些种在简化生态系统中的相对适应性的影响。基因的身份对特定非酵母在批式培养中延长生长周期过程中的持续存在有显著影响。值得注意的是，和表达通常会产生相反的结果。这些数据为物理接触在多物种酵母生态系统中的作用提供了明确的证据，并表明基因表达可能是这种相互作用的主要因素。直接（物理）与不同酵母种间的间接（代谢）相互作用的影响近年来引起了人们的极大兴趣。这是由于人们对在具有工业相关性的生物过程中使用多物种联合体以及在建立稳定的合成生态系统中种间相互作用的相关性的兴趣日益增加。传统上，使用分区生物反应器来解决这个问题，但它存在许多局限性。在这里，我们使用基于基因家族的遗传系统来提供物理接触重要性的独立证据，该系统可改变物理接触的程度，从而改变酵母中种内和种间无性黏附的程度。我们的结果表明，种间接触显著影响种群动态和个体物种的生存。值得注意的是，基因家族的不同成员通常会导致非常不同的种群结果，这进一步表明基因表达可能是这种相互作用的主要因素。
