背景:珠穆朗玛峰和马里亚纳海沟是地球上最高和最深的地方,分别。它们在地理上是分开的,具有独特的极端环境参数,为原核生物提供独特的栖息地。珠穆朗玛峰和马里亚纳海沟之间的原核生物的比较将为了解地球上环境微生物组的组成和分布提供独特的视角。
结果:这里,我们比较了珠穆朗玛峰和马里亚纳海沟之间的原核群落基于鸟枪宏基因组分析。分析25个宏基因组和1176个宏基因组组装的基因组显示出珠穆朗玛峰和马里亚纳海沟之间不同的分类组成,小分类单元重叠,和基因组大小的显著差异,GC含量,并预测了最佳生长温度。然而,群落代谢能力表现出惊人的共性,珠穆朗玛峰和马里亚纳海沟样本中>90%的代谢模块重叠,唯一的例外是CO2固定(珠穆朗玛峰的光自养,但马里亚纳海沟的化学自养)。大多数代谢途径是常见的,但在两个极端生境中由不同的分类单元执行,甚至包括一些专门的代谢途径,例如各种难降解有机物的多功能降解,重金属代谢(例如,As和Se),抗应力,和抗氧化。尽管珠穆朗玛峰和马里亚纳海沟在直观上存在巨大差异,但代谢共性表明原核生物在元素循环中的总体作用和克服不同压力条件的共同适应策略。
结论:我们的结果,地球上最高和最深栖息地的原核生物之间的第一次比较,可能会强调原核生物多样性的原理:尽管分类单元是特定于栖息地的,主要代谢功能可以始终保留。视频摘要。
Mount Everest and the Mariana Trench represent the highest and deepest places on Earth, respectively. They are geographically separated, with distinct extreme environmental parameters that provide unique habitats for prokaryotes. Comparison of prokaryotes between Mount Everest and the Mariana Trench will provide a unique perspective to understanding the composition and distribution of environmental microbiomes on Earth.
Here, we compared prokaryotic communities between Mount Everest and the Mariana Trench based on shotgun metagenomic analysis. Analyzing 25 metagenomes and 1176 metagenome-assembled genomes showed distinct taxonomic compositions between Mount Everest and the Mariana Trench, with little taxa overlap, and significant differences in genome size, GC content, and predicted optimal growth temperature. However, community metabolic capabilities exhibited striking commonality, with > 90% of metabolic modules overlapping among samples of Mount Everest and the Mariana Trench, with the only exception for CO2 fixations (photoautotrophy in Mount Everest but chemoautotrophy in the Mariana Trench). Most metabolic pathways were common but performed by distinct taxa in the two extreme habitats, even including some specialized metabolic pathways, such as the versatile degradation of various refractory organic matters, heavy metal metabolism (e.g., As and Se), stress resistance, and antioxidation. The metabolic commonality indicated the overall consistent roles of prokaryotes in elemental cycling and common adaptation strategies to overcome the distinct stress conditions despite the intuitively huge differences in Mount Everest and the Mariana Trench.
Our results, the first comparison between prokaryotes in the highest and the deepest habitats on Earth, may highlight the principles of prokaryotic diversity: although taxa are habitat-specific, primary metabolic functions could be always conserved. Video abstract.