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Functional interactions of archaea, bacteria and viruses in a hypersaline endolithic community
Author(s) -
CritsChristoph Alexander,
Gelsinger Diego R.,
Ma Bing,
Wierzchos Jacek,
Ravel Jacques,
Davila Alfonso,
Casero M. Cristina,
DiRuggiero Jocelyne
Publication year - 2016
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.13259
Subject(s) - biology , haloarchaea , archaea , genome , extreme environment , halite , metagenomics , gammaproteobacteria , ecology , bacteria , genetics , gene , 16s ribosomal rna , paleontology , gypsum
Summary Halite endoliths in the Atacama Desert represent one of the most extreme ecosystems on Earth. Cultivation‐independent methods were used to examine the functional adaptations of the microbial consortia inhabiting halite nodules. The community was dominated by haloarchaea and functional analysis attributed most of the autotrophic CO 2 fixation to one unique cyanobacterium. The assembled 1.1 Mbp genome of a novel nanohaloarchaeon, Candidatus Nanopetramus SG9, revealed a photoheterotrophic life style and a low median isoelectric point (pI) for all predicted proteins, suggesting a ‘salt‐in’ strategy for osmotic balance. Predicted proteins of the algae identified in the community also had pI distributions similar to ‘salt‐in’ strategists. The Nanopetramus genome contained a unique CRISPR/Cas system with a spacer that matched a partial viral genome from the metagenome. A combination of reference‐independent methods identified over 30 complete or near complete viral or proviral genomes with diverse genome structure, genome size, gene content and hosts. Putative hosts included Halobacteriaceae , Nanohaloarchaea and Cyanobacteria . Despite the dependence of the halite community on deliquescence for liquid water availability, this study exposed an ecosystem spanning three phylogenetic domains, containing a large diversity of viruses and predominance of a ‘salt‐in’ strategy to balance the high osmotic pressure of the environment.