University of Cologne, Cologne Biocenter, Institute of Zoology, General Ecology, Zuelpicher Str. 47b, D-50674 Cologne, Germany.
University of Cologne, Cologne Biocenter, Institute of Zoology, General Ecology, Zuelpicher Str. 47b, D-50674 Cologne, Germany.
Eur J Protistol. 2021 Jun;79:125798. doi: 10.1016/j.ejop.2021.125798. Epub 2021 Apr 23.
In contrast to previous perspectives, hypersaline environments have been proven to harbour a variety of potentially highly adapted microorganisms, in particular unicellular eukaryotes. The isolated, hypersaline waterbodies in the Atacama Desert, Northern Chile are exposed to high UV radiation and deposition of toxic heavy metals, making them of great interest regarding studies on speciation and evolutionary processes. In the past two years, among a variety of other protist species, five new species of heterotrophic choanoflagellates were described and analysed from this area, showing an adaptation to a broad range of salinities. Morphological data alone does not allow for species delineation within craspedid species, additional molecular data is essential for modern taxonomy. In addition, molecular clock analyses pointed towards a strong selection force of the extreme environmental conditions. Within this study, we describe three additional craspedid choanoflagellate species, isolated from different aquatic environments. Phylogenetic analyses show two distinct clades of choanoflagellates from the Atacama, suggesting two independent invasions of at least two ancestral marine species, and, as indicated by our new data, a possible dispersal by Andean aquifers. The extended molecular clock analysis based on transcriptomic data of choanoflagellate strains from the Salar de Llamará, a hypersaline basin within the Central Depression of the Atacama Desert, reflects colonisation and divergence events which correspond to geological data of the paleohydrology.
与先前的观点相反，已证明高盐环境中存在各种具有潜在高度适应性的微生物，特别是单细胞真核生物。智利北部阿塔卡马沙漠中孤立的高盐水体暴露在高强度的紫外线下，并且还会沉积有毒重金属，这使得它们成为研究物种形成和进化过程的热点。在过去的两年中，在该地区从各种其他原生动物物种中描述和分析了五种新的异养领鞭毛生物，它们表现出对广泛盐度范围的适应性。仅形态数据不足以在棘尾虫属物种内进行物种划分，额外的分子数据对于现代分类学至关重要。此外，分子钟分析表明，极端环境条件具有强大的选择力。在本研究中，我们描述了另外三种来自不同水生环境的棘尾虫属领鞭毛生物。系统发育分析显示，来自阿塔卡马的领鞭毛生物有两个截然不同的分支，表明至少有两个原始海洋物种的两次独立入侵，并且正如我们的新数据所表明的，可能是通过安第斯含水层进行的扩散。基于来自阿塔卡马沙漠中央洼地盐沼的转录组数据的扩展分子钟分析反映了与古水文学地质数据相对应的殖民化和分化事件。
