PDF(Pubmed)
Abstract：
Siderophores are crucial for iron-scavenging in microorganisms. While many yeasts can uptake siderophores produced by other organisms, they are typically unable to synthesize siderophores themselves. In contrast, Wickerhamiella/Starmerella (W/S) clade yeasts gained the capacity to make the siderophore enterobactin following the remarkable horizontal acquisition of a bacterial operon enabling enterobactin synthesis. Yet, how these yeasts absorb the iron bound by enterobactin remains unresolved. Here, we demonstrate that Enb1 is the key enterobactin importer in the W/S-clade species Starmerella bombicola. Through phylogenomic analyses, we show that ENB1 is present in all W/S clade yeast species that retained the enterobactin biosynthetic genes. Conversely, it is absent in species that lost the ent genes, except for Starmerella stellata, making this species the only cheater in the W/S clade that can utilize enterobactin without producing it. Through phylogenetic analyses, we infer that ENB1 is a fungal gene that likely existed in the W/S clade prior to the acquisition of the ent genes and subsequently experienced multiple gene losses and duplications. Through phylogenetic topology tests, we show that ENB1 likely underwent horizontal gene transfer from an ancient W/S clade yeast to the order Saccharomycetales, which includes the model yeast Saccharomyces cerevisiae, followed by extensive secondary losses. Taken together, these results suggest that the fungal ENB1 and bacterial ent genes were cooperatively integrated into a functional unit within the W/S clade that enabled adaptation to iron-limited environments. This integrated fungal-bacterial circuit and its dynamic evolution determine the extant distribution of yeast enterobactin producers and cheaters.
摘要：
铁载体对于微生物中的铁清除至关重要。虽然许多酵母可以吸收其他生物产生的铁载体，它们通常无法自己合成铁载体。相比之下,Wickerhamiella/Starmerella（W/S）进化枝酵母在显着的水平获得能够合成肠杆菌素的细菌操纵子后，获得了制造铁载体肠杆菌素的能力。然而，这些酵母如何吸收肠杆菌素结合的铁仍未解决。这里,我们证明Enb1是W/S进化枝物种Starmerellabombicola中的关键肠杆菌转运蛋白。通过系统基因组分析，我们表明，ENB1存在于所有保留肠杆菌素生物合成基因的W/S进化枝酵母物种中。相反，它在丢失了ent基因的物种中不存在，除了StarmerellaStellata,使该物种成为W/S进化枝中唯一可以利用肠杆菌素而不产生肠杆菌素的骗子。通过系统发育分析，我们推断ENB1是一种真菌基因,在获得ent基因之前可能存在于W/S进化枝中,随后经历了多个基因丢失和重复.通过系统发育拓扑测试，我们表明，ENB1可能经历了从一个古老的W/S进化枝酵母到酵母顺序的水平基因转移，其中包括酿酒酵母模型，其次是广泛的二次损失。一起来看,这些结果表明,真菌ENB1和细菌ent基因协同整合到W/S进化枝的一个功能单元中,从而能够适应铁限制环境.这种集成的真菌-细菌回路及其动态演变决定了酵母肠杆菌素生产者和骗子的现有分布。
