Publication Date:
2022-05-26
Description:
Author Posting. © The Author(s), 2012. This is the author's version of the work. It is posted here by permission of National Academy of Sciences for personal use, not for redistribution. The definitive version was published in Proceedings of the National Academy of Sciences of the United States of America 110 (2013): 330-335, doi:10.1073/pnas.1215340110.
Description:
Hydrothermal vents are a well-known source of energy that powers chemosynthesis in the
deep sea. Recent work suggests that microbial chemosynthesis is also surprisingly pervasive
throughout the dark oceans, serving as a significant CO2 sink even at sites far-removed
from vents. Ammonia and sulfur have been identified as potential electron donors for this
chemosynthesis, but they do not fully account for measured rates of dark primary
production in the pelagic water column. Here we use metagenomic and metatranscriptomic
analyses to show that deep-sea populations of the SUP05 group of uncultured sulfur
oxidizing Gammaproteobacteria, which are abundant in widespread and diverse marine
environments, contain and highly express genes encoding group 1 Ni-Fe hydrogenase
enzymes for H2 oxidation. Reconstruction of near-complete genomes of two co-occurring
SUP05 populations in hydrothermal plumes and deep waters of the Gulf of California
enabled detailed population-specific metatranscriptomic analyses, revealing dynamic
patterns of gene content and transcript abundance. SUP05 transcripts for genes involved in
H2 and sulfur oxidation are most abundant in hydrothermal plumes where these electron
donors are enriched. In contrast, a second hydrogenase has more abundant transcripts in
background deep sea samples. Coupled with results from a bioenergetic model that suggest
that H2 oxidation can contribute significantly to the SUP05 energy budget, these findings
reveal the potential importance of H2 as a key energy source in the deep ocean. This study
also highlights the genomic plasticity of SUP05, which enables this widely distributed group
to optimize its energy metabolism (electron donor and acceptor) to local geochemical
conditions.
Description:
This project is funded in part by the Gordon and Betty Moore Foundation
and the National Science Foundation (OCE 1029242).
Keywords:
Metagenomics
;
Metatranscriptomics
;
SUP05
;
Hydrogen oxidation
;
Deep oceans
Repository Name:
Woods Hole Open Access Server
Type:
Preprint
Format:
application/pdf
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