Data from: Organelles that illuminate the origins of Trichomonas hydrogenosomes and Giardia mitosomes

Many anaerobic microbial parasites possess highly modified mitochondria known as mitochondrion-related organelles (MROs). The best-studied of these are the hydrogenosomes of Trichomonas vaginalis and Spironucleus salmonicida, which produce ATP anaerobically through substrate-level phosphorylation with concomitant hydrogen production; and the mitosomes of Giardia intestinalis, which are functionally reduced and lack any role in ATP production. However, to understand the metabolic specializations that these MROs underwent in adaptation to parasitism, data from their free-living relatives are needed. Here, we present a large-scale comparative transcriptomic study of MROs across a major eukaryotic group, Metamonada, examining lineage-specific gain and loss of metabolic functions in the MROs of Trichomonas, Giardia, Spironucleus and their free-living relatives. Our analyses uncover a complex history of ATP production machinery in diplomonads such as Giardia, and their closest relative, Dysnectes; and a correlation between the glycine cleavage machinery and lifestyles. Our data further suggest the existence of a previously undescribed biochemical class of MRO that generates hydrogen but is incapable of ATP synthesis.许多厌氧微生物寄生虫拥有高度特化修饰的线粒体，这类细胞器被称为线粒体相关细胞器（mitochondrion-related organelles，MROs）。其中研究最为深入的是阴道毛滴虫（Trichomonas vaginalis）和鲑生螺菌（Spironucleus salmonicida）的氢化酶体，它们可通过底物水平磷酸化进行厌氧ATP合成并伴随氢气产生；以及肠贾第鞭毛虫（Giardia intestinalis）的纺锤剩体，这类细胞器功能简化，不参与ATP生成。然而，要阐明这些线粒体相关细胞器在适应寄生生活过程中演化出的代谢特化特征，亟需获取其自由生活近亲的相关数据。本研究针对大型真核类群后滴门（Metamonada）内的线粒体相关细胞器开展了大规模比较转录组学分析，旨在探究毛滴虫、贾第鞭毛虫、螺菌及其自由生活近亲的线粒体相关细胞器中，各演化支特有的代谢功能获得与丢失事件。本研究的分析揭示了以贾第鞭毛虫及其近缘类群Dysnectes为代表的双滴虫类群中ATP合成机制的复杂演化历史，同时发现甘氨酸裂解系统与生物类群的生活方式存在显著关联。本研究的数据还提示，存在一类此前未被报道的、可产生氢气但无法合成ATP的线粒体相关细胞器生化亚型。