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Proc Natl Acad Sci U S A. 2018 Oct 16;115(42):10702-10707. doi: 10.1073/pnas.1808176115. Epub 2018 Oct 1.

Viable cyanobacteria in the deep continental subsurface.

Author information

1
Department of Molecular Evolution, Centro de Astrobiología, Instituto Nacional de Técnica Aeroespacial-Consejo Superior de Investigaciones Científicas (INTA-CSIC), 28850 Torrejón de Ardoz, Madrid, Spain; fpuente@cnb.csic.es.
2
Institute of Microbiology, Technical University Braunschweig, D-38023 Braunschweig, Germany.
3
Microbial Interactions and Processes Group, Helmholtz Zentrum für Infektionsforschung, 38124 Braunschweig, Germany.
4
Department of Planetology and Habitability, Centro de Astrobiología, INTA-CSIC, 28850 Torrejón de Ardoz, Madrid, Spain.
5
Department of Molecular Evolution, Centro de Astrobiología, Instituto Nacional de Técnica Aeroespacial-Consejo Superior de Investigaciones Científicas (INTA-CSIC), 28850 Torrejón de Ardoz, Madrid, Spain.
6
Department of Geosciences, The Pennsylvania State University, University Park, PA 16802.
7
Instituto de Geociencias, CSIC-Universidad Complutense de Madrid, 28040 Madrid, Spain.
8
Centro de Biología Molecular Severo Ochoa, CSIC-Universidad Autónoma de Madrid, 28049 Madrid, Spain.

Abstract

Cyanobacteria are ecologically versatile microorganisms inhabiting most environments, ranging from marine systems to arid deserts. Although they possess several pathways for light-independent energy generation, until now their ecological range appeared to be restricted to environments with at least occasional exposure to sunlight. Here we present molecular, microscopic, and metagenomic evidence that cyanobacteria predominate in deep subsurface rock samples from the Iberian Pyrite Belt Mars analog (southwestern Spain). Metagenomics showed the potential for a hydrogen-based lithoautotrophic cyanobacterial metabolism. Collectively, our results suggest that they may play an important role as primary producers within the deep-Earth biosphere. Our description of this previously unknown ecological niche for cyanobacteria paves the way for models on their origin and evolution, as well as on their potential presence in current or primitive biospheres in other planetary bodies, and on the extant, primitive, and putative extraterrestrial biospheres.

KEYWORDS:

astrobiology; deep/dark biosphere; endolithic cyanobacteria; extreme environments; metagenomics

PMID:
30275328
PMCID:
PMC6196553
DOI:
10.1073/pnas.1808176115
[Indexed for MEDLINE]
Free PMC Article

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