Phylogeography, Salinity Adaptations and Metabolic Potential of the Candidate Division KB1 Bacteria Based on a Partial Single Cell Genome.

Lisa M Nigro,Andreas Teske,Barbara J Macgregor,Andrew S Hyde

doi:10.3389/fmicb.2016.01266

Lisa M Nigro, Andreas Teske + Show 2 more

Open Access

https://doi.org/10.3389/fmicb.2016.01266

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Abstract

Deep-sea hypersaline anoxic basins and other hypersaline environments contain abundant and diverse microbial life that has adapted to these extreme conditions. The bacterial Candidate Division KB1 represents one of several uncultured groups that have been consistently observed in hypersaline microbial diversity studies. Here we report the phylogeography of KB1, its phylogenetic relationships to Candidate Division OP1 Bacteria, and its potential metabolic and osmotic stress adaptations based on a partial single cell amplified genome of KB1 from Orca Basin, the largest hypersaline seafloor brine basin in the Gulf of Mexico. Our results are consistent with the hypothesis – previously developed based on 14C incorporation experiments with mixed-species enrichments from Mediterranean seafloor brines – that KB1 has adapted its proteins to elevated intracellular salinity, but at the same time KB1 apparently imports glycine betaine; this compatible solute is potentially not limited to osmoregulation but could also serve as a carbon and energy source.

Highlights

Hypersaline environments are abundant on Earth (e.g., Boetius and Joye, 2009) and include hypersaline lakes, such as the Dead Sea or the Great Salt Lake; evaporative lagoons; salterns; and hypersaline marine basins where salt deposits dissolve into deep-sea water and create distinct “lakes” of high-density brines on the seafloor of the Red Sea, Mediterranean Sea and Gulf of Mexico
We report the phylogeography of KB1, its phylogenetic relationships to Candidate Division OP1 Bacteria, and its potential metabolic roles and osmotic stress strategies based on a partial single cell amplified genome (SAG) from Orca Basin, the largest hypersaline seafloor brine basin in the Gulf of Mexico (Shokes et al, 1977; Pilcher and Blumstein, 2007)
The sample was processed for single cell sorting followed by multiple displacement amplification of cellular DNA and PCR screening of bacterial 16S rRNA genes (Martinez-Garcia et al, 2012; Stepanauskas, 2012)

Summary

Introduction

Hypersaline environments are abundant on Earth (e.g., Boetius and Joye, 2009) and include hypersaline lakes, such as the Dead Sea or the Great Salt Lake; evaporative lagoons; salterns; and hypersaline marine basins where salt deposits dissolve into deep-sea water and create distinct “lakes” of high-density brines on the seafloor of the Red Sea, Mediterranean Sea and Gulf of Mexico. We report the phylogeography of KB1, its phylogenetic relationships to Candidate Division OP1 Bacteria, and its potential metabolic roles and osmotic stress strategies based on a partial single cell amplified genome (SAG) from Orca Basin, the largest hypersaline seafloor brine basin in the Gulf of Mexico (Shokes et al, 1977; Pilcher and Blumstein, 2007).

Results

Conclusion