Abstract：
Protosteloid amoebae are a paraphyletic assemblage of amoeboid protists found exclusively in the eukaryotic assemblage Amoebozoa. These amoebae can facultatively form a dispersal structure known as a fruiting body, or more specifically, a sporocarp, from a single amoeboid cell. Sporocarps consist of one to a few spores atop a noncellular stalk. Protosteloid amoebae are known in two out of three well-established major assemblages of Amoebozoa. Amoebae with a protosteloid life cycle are known in the major Amoebozoa lineages Discosea and Evosea but not in Tubulinea. To date, only one genus, which is monotypic, lacks sequence data and, therefore, remains phylogenetically homeless. To further clarify the evolutionary milieu of sporocarpic fruiting we used single-cell transcriptomics to obtain data from individual sporocarps of isolates of the protosteloid amoeba Microglomus paxillus. Our phylogenomic analyses using 229 protein coding markers suggest that M. paxillus is a member of the Discosea lineage of Amoebozoa most closely related to Mycamoeba gemmipara. Due to the hypervariable nature of the SSU rRNA sequence we were unable to further resolve the phylogenetic position of M. paxillus in taxon rich datasets using only this marker. Regardless, our results widen the known distribution of sporocarpy in Discosea and stimulate the debate between a single or multiple origins of sporocarpic fruiting in Amoebozoa.
摘要：
原虫变形虫是仅在真核生物变形虫中发现的变形虫的近亲组合。这些变形虫可以同时形成一种被称为子实体的分散结构，或者更具体地说，一种子果皮,来自一个变形虫细胞。孔果由非细胞茎顶上的一到几个孢子组成。在三个成熟的变形虫主要组合中，有两个是原虫变形虫。在主要的变形虫谱系Discosea和Evosea中已知具有原石样生命周期的变形虫，但在Tubulinea中却不知道。迄今为止,只有一个属,这是单型的，缺少序列数据，因此,在系统发育方面仍然无家可归。为了进一步阐明孢子果的进化环境，我们使用单细胞转录组学从原类阿米巴微glomuspaxillus分离株的单个孢子果获得数据。我们使用229个蛋白质编码标记进行的系统学分析表明，M.paxillus是与Mycamoebagemmipara最密切相关的AmoebozoaDiscosea谱系的成员。由于SSUrRNA序列的高变性质，我们无法仅使用该标记进一步解析分类单元丰富数据集中的M.paxillus的系统发育位置。无论如何,我们的结果扩大了Discosea中孢果的已知分布，并激发了变形虫中孢果的单个或多个起源之间的争论。
