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. Colwellia eventually supplanted Oceanospirillales, 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. Colwellia abundance peaked when gaseous and simple aromatic hydrocarbons increased, yet the metabolic pathway used by Colwellia in hydrocarbon disposition is unknown. Here we used single-cell genomics to gain insights into the genome properties of a Colwellia enriched during the DWH deep-sea plume. A single amplified genome (SAG) of a Colwellia cell isolated from a DWH plume, closely related (avg. 98% 16S rRNA gene similarity) to other plume Colwellia, was sequenced and annotated. The SAG was similar to the sequenced isolate Colwellia psychrerythraea 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 Colwellia SAG may be capable of gaseous and aromatic hydrocarbon degradation, which contrasts with a DWH plume Oceanospirillales SAG which encoded non-gaseous n-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 n-alkanes and cycloalkanes that could be degraded by Oceanospirillales, followed by gaseous, and simple aromatic hydrocarbons that may have been degraded by Colwellia. These insights into the genomic properties of a Colwellia 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.
Keywords: DWH oil spill, Colwellia, single-cell genomics, deep-sea plume, hydrocarbon degradation, bacteria
Citation: Mason OU, Han J, Woyke T and Jansson JK (2014) Single-cell genomics reveals features of a Colwellia species that was dominant during the Deepwater Horizon oil spill. Front. Microbiol. 5:332. doi: 10.3389/fmicb.2014.00332
Received: 01 November 2013; Accepted: 16 June 2014;
Published online: 08 July 2014.
Edited by:Ian M. Head, Newcastle University, UK
Reviewed by:Vanessa Karel Michelou, University of Hawaii, USA
Copyright © 2014 Mason, Han, Woyke and Jansson. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Olivia U. Mason, Department of Earth, Ocean and Atmospheric Science, Florida State University, 117 N Woodward Avenue, Rogers Building Rm. 307, Tallahassee, FL, USA e-mail: email@example.com;
Janet K. Jansson, 1 Cyclotron Road, Berkeley, CA, USA e-mail: firstname.lastname@example.org