Abstract：
Protists can endure challenging environments sustaining key ecosystem processes of the microbial food webs even under aridic or hypersaline conditions. We studied the diversity of protists at different latitudes of the Atacama Desert by massive sequencing of the hypervariable region V9 of the 18S rRNA gene from soils and microbial mats collected in the Andes. The main protist groups in soils detected in active stage through cDNA were cercozoans, ciliates, and kinetoplastids, while the diversity of protists was higher including diatoms and amoebae in the microbial mat detected solely through DNA. Co-occurrence networks from soils indicated similar assemblages dominated by amplicon sequence variants (ASVs) identified as Rhogostoma, Euplotes, and Neobodo. Microbial mat networks, on the other hand, were structured by ASVs classified as raphid-pennate diatoms and amoebae from the genera Hartmannella and Vannella, mostly negatively correlated to flagellates and microalgae. Additionally, our phylogenetic inferences of ASVs classified as Euplotes, Neobodo, and Rhogostoma were supported by sequence data of strains isolated during this study. Our results represent the first snapshot of the diversity patterns of culturable and unculturable protists and putative keystone taxa detected at remote habitats from the Atacama Desert.
摘要：
即使在阿利迪奇或高盐条件下，原生生物也可以忍受具有挑战性的环境，维持微生物食物网的关键生态系统过程。我们通过对安第斯山脉收集的土壤和微生物垫中18SrRNA基因的高变区V9进行大规模测序，研究了阿塔卡马沙漠不同纬度的原生生物多样性。通过cDNA检测到的活跃阶段土壤中的主要原生生物类群是cercozoans，纤毛虫,和动体，而原生生物的多样性更高，包括仅通过DNA检测到的微生物垫中的硅藻和变形虫。来自土壤的共现网络表明类似的组合由鉴定为Rhogostoma的扩增子序列变体（ASV）主导，Euplotes,还有Neobodo.微生物垫网络，另一方面,由被分类为Hartmannella和Vannella属的raphid-pennate硅藻和变形虫的ASV构成，主要与鞭毛虫和微藻呈负相关。此外,我们对ASV的系统发育推断被归类为Euplots，Neobodo,和Rhogostoma得到了本研究中分离菌株的序列数据的支持。我们的结果代表了在阿塔卡马沙漠偏远栖息地发现的可培养和不可培养的原生生物和推定的梯形分类群的多样性模式的第一个快照。
