Novel Metagenome-Assembled Genomes from Siberian Marine Sediment Expand the Diversity of Candidatus Coatesbacteria Phylum
Abstract
Metagenomics has provided a valuable tool for discovering the uncultivated majority representing the "microbial dark matter" in diverse ecosystems. Yet the better understanding of entire "microbial dark matter" relies on extensive environmental samples. The recently defined phylum of "Candidatus Coatesbacteria" remains under-explored due to the lack of cultivated representatives and a limited number of metagenome-assembled genomes (MAGs), the existing of which originate from deep sea hydrothermal vent and hot spring sediments. Deep metagenomic sequencing was employed to recover two high-quality MAGs (96.15% and 89.01% completeness) from Siberian marine sediment, frozen over 100 kyr ago. Phylogenomic analysis reveals that the two permafrost MAGs belong to the Coatesbacteria phylum, thus expanding the genomic and geographic diversity of this Candidatus phylum. The low value of average amino acid identity (AAI) between permafrost MAGs and previously published Coatesbacteria MAGs (<50%) suggested that the permafrost MAGs might be phylogenetically novel at sub-phylum level. The two permafrost MAGs are closely related to each other (AAI > 70%). Annotation of the permafrost MAGs showed the bacteria to be anaerobes, notably lacking cytochrome c oxidase for aerobic respiration, similar to other Coatesbacteria. The identification of Embden-Meyerhof and pentose phosphate pathway suggested the genetic potential for heterotrophic carbon metabolism in these two MAGs. Furthermore, these novel bacteria appear to be capable of ethanol metabolism, butyrate fermentation, and beta-oxidation of fatty acids. Further insight could be provided through pangenome analysis of Coatesbacteria-related MAGs from permafrost and non-permafrost sediment sampled from geographically different regions.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMB113.0003B
- Keywords:
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- 0428 Carbon cycling;
- BIOGEOSCIENCES;
- 0439 Ecosystems;
- structure and dynamics;
- BIOGEOSCIENCES;
- 0465 Microbiology: ecology;
- physiology and genomics;
- BIOGEOSCIENCES;
- 1615 Biogeochemical cycles;
- processes;
- and modeling;
- GLOBAL CHANGE