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Extensive gene acquisition in the extremely psychrophilic bacterial species Psychroflexus torquis and the link to sea-ice ecosystem specialism


Feng, S and Powell, SM and Wilson, R and Bowman, JP, Extensive gene acquisition in the extremely psychrophilic bacterial species Psychroflexus torquis and the link to sea-ice ecosystem specialism, Genome Biology and Evolution, 6, (1) pp. 133-148. ISSN 1759-6653 (2014) [Refereed Article]


Copyright Statement

Copyright 2014 The Authors Lisenced under Creative Commons Attribution-NonCommercial 3.0 Unported (CC BY-NC 3.0)

DOI: doi:10.1093/gbe/evt209


Sea ice is a highly dynamic and productive environment that includes a diverse array of psychrophilic prokaryotic and eukaryotic taxa distinct from the underlying water column. Because sea ice has only been extensive on Earth since the mid-Eocene, it has been hypothesized that bacteria highly adapted to inhabit sea ice have traits that have been acquired through horizontal gene transfer (HGT). Here we compared the genomes of the psychrophilic bacterium Psychroflexus torquis ATCC 700755T, associated with both Antarctic and Arctic sea ice, and its closely related nonpsychrophilic sister species, P. gondwanensis ACAM 44T. Results show that HGT has occurredmuchmore extensively in P. torquis in comparison to P. gondwanensis. Genetic features that can be linked to the psychrophilic and sea ice-specific lifestyle of P. torquis include genes for exopolysaccharide (EPS) and polyunsaturated fatty acid (PUFA) biosynthesis, numerous specific modes of nutrient acquisition, and proteins putatively associated with ice-binding, light-sensing (bacteriophytochromes), and programmed cell death (metacaspases). Proteomic analysis showed that several genes associated with these traits are highly translated, especially those involved with EPS and PUFA production. Becausemost of the genes relating to the ability of P. torquis to dwell in sea-ice ecosystems occur on genomic islands that are absent in closely related P. gondwanensis, its adaptation to the sea-ice environment appears driven mainly by HGT. The genomic islands are rich in pseudogenes, insertional elements, and addiction modules, suggesting that gene acquisition is being followed by a process of genome reduction potentially indicative of evolving ecosystem specialism.

Item Details

Item Type:Refereed Article
Keywords:psychrophilic bacteria, horizontal gene transfer, proteomics, sea ice, ecosystem specialism
Research Division:Biological Sciences
Research Group:Microbiology
Research Field:Microbial ecology
Objective Division:Environmental Management
Objective Group:Management of Antarctic and Southern Ocean environments
Objective Field:Biodiversity in Antarctic and Southern Ocean environments
UTAS Author:Feng, S (Mr Shi Feng)
UTAS Author:Powell, SM (Dr Shane Powell)
UTAS Author:Wilson, R (Dr Richard Wilson)
UTAS Author:Bowman, JP (Associate Professor John Bowman)
ID Code:88505
Year Published:2014
Web of Science® Times Cited:34
Deposited By:Tasmanian Institute of Agriculture
Deposited On:2014-02-05
Last Modified:2017-11-02
Downloads:666 View Download Statistics

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