AUTHOR=Mason Olivia U. , Han James , Woyke Tanja , Jansson Janet K. 

TITLE=Single-cell genomics reveals features of a Colwellia species that was dominant during the Deepwater Horizon oil spill

JOURNAL=Frontiers in Microbiology

VOLUME=5

YEAR=2014

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2014.00332

DOI=10.3389/fmicb.2014.00332

ISSN=1664-302X

ABSTRACT=<p>During the Deepwater Horizon (DWH) oil spill in the Gulf of Mexico a deep-sea hydrocarbon plume developed resulting in a rapid succession of bacteria. <italic>Colwellia</italic> eventually supplanted <italic>Oceanospirillales</italic>, which dominated the plume early in the spill. These successional changes may have resulted, in part, from the changing composition and abundance of hydrocarbons over time. <italic>Colwellia</italic> abundance peaked when gaseous and simple aromatic hydrocarbons increased, yet the metabolic pathway used by <italic>Colwellia</italic> in hydrocarbon disposition is unknown. Here we used single-cell genomics to gain insights into the genome properties of a <italic>Colwellia</italic> enriched during the DWH deep-sea plume. A single amplified genome (SAG) of a <italic>Colwellia</italic> cell isolated from a DWH plume, closely related (avg. 98% 16S rRNA gene similarity) to other plume <italic>Colwellia</italic>, was sequenced and annotated. The SAG was similar to the sequenced isolate <italic>Colwellia psychrerythraea</italic> 34H (84% avg. nucleotide identity). Both had genes for denitrification, chemotaxis, and motility, adaptations to cold environments and a suite of nutrient acquisition genes. The <italic>Colwellia</italic> SAG may be capable of gaseous and aromatic hydrocarbon degradation, which contrasts with a DWH plume <italic>Oceanospirillales</italic> SAG which encoded non-gaseous <italic>n</italic>-alkane and cycloalkane degradation pathways. The disparate hydrocarbon degradation pathways are consistent with hydrocarbons that were abundant at different times in the deep-sea plume; first, non-gaseous <italic>n</italic>-alkanes and cycloalkanes that could be degraded by <italic>Oceanospirillales</italic>, followed by gaseous, and simple aromatic hydrocarbons that may have been degraded by <italic>Colwellia</italic>. These insights into the genomic properties of a <italic>Colwellia</italic> species, which were supported by existing metagenomic sequence data from the plume and DWH contaminated sediments, help further our understanding of the successional changes in the dominant microbial players in the plume over the course of the DWH spill.</p>