科研之友
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摘要
Premise of research.Abundant peat mosses and epibiotic microbiota, common in widespread modern peatlands, constitute complex biotic systems recognized to provide globally significant ecosystem services: organic carbon sequestration, methane oxidation, and nitrogen fixation. Because recent fossil and molecular diversification evidence indicates that peat mosses are >450 Myr old, they may be among Earth's earliest land plants. The biogeochemical effects of early vegetation, which may have occupied remote islands and experienced nutritional stress and episodes of high UV radiation, are poorly understood. To gain insight into taxonomic composition, biogeochemical function, and resilience of archaic peat moss microbiomes, we performed shotgun metagenomic sequencing of a similarly stressed modern peat moss. Methodology.Sphagnum fimbriatum was sampled from Chilean sub-Antarctic Navarino Island, which is remote from nutrient pollution and subject to high UV beneath the southern ozone hole. 16S, 18S, 23S, and 28S ribosomal RNA sequences filtered from contigs assembled from long-read Roche 454 and deep short-read Illumina sequences were employed to infer prokaryotic and eukaryotic microbiome composition at generic and higher levels for comparison to peat moss microbiota reported for other locales. Pivotal results.Comparison of bacterial diversityincluding >75 genera represented by 100 sequence reads and >250 genera represented by 10 readsto diversity reported from previous peatland studies indicated the operation of recognized peatland functions (carbon sequestration, methane oxidation, and nitrogen fixation), signifying stress resilience. Eukaryotic features included >45 protist genera, some of pivotal evolutionary significance; distinctive fungal associations; and ancient lineages of microscopic invertebrate animals, including springtails known to foster moss reproduction. Conclusions.Metagenomic approaches provide a new, expanding window into early terrestrial vegetation and its biogeochemical effects, indicating that complex peat moss systems resilient to stressful environmental conditions likely occurred in deep time and persist to the present.
- 出版日期2017-10
