title: Metagenomic analysis of stress genes in microbial mat communities from Antarctica and the High Arctic.
abstract: Polar and alpine microbial communities experience a variety of environmental stresses, including perennial cold and freezing; however, knowledge of genomic responses to such conditions is still rudimentary. We analyzed the metagenomes of cyanobacterial mats from Arctic and Antarctic ice shelves, using high-throughput pyrosequencing to test the hypotheses that consortia from these extreme polar habitats were similar in terms of major phyla and subphyla and consequently in their potential responses to environmental stresses. Statistical comparisons of the protein-coding genes showed similarities between the mats from the two poles, with the majority of genes derived from Proteobacteria and Cyanobacteria; however, the relative proportions differed, with cyanobacterial genes more prevalent in the Antarctic mat metagenome. Other differences included a higher representation of Actinobacteria and Alphaproteobacteria in the Arctic metagenomes, which may reflect the greater access to diasporas from both adjacent ice-free lands and the open ocean. Genes coding for functional responses to environmental stress (exopolysaccharides, cold shock proteins, and membrane modifications) were found in all of the metagenomes. However, in keeping with the greater exposure of the Arctic to long-range pollutants, sequences assigned to copper homeostasis genes were statistically (30%) more abundant in the Arctic samples. In contrast, more reads matching the sigma B genes were identified in the Antarctic mat, likely reflecting the more severe osmotic stress during freeze-up of the Antarctic ponds. This study underscores the presence of diverse mechanisms of adaptation to cold and other stresses in polar mats, consistent with the proportional representation of major bacterial groups.
authors.affiliation: Faculté de Médecine, Université Laval, Québec, QC, Canada.
authors.forename: Thibault
authors.initials: T
authors.lastname: Varin
authors.forename: Connie
authors.initials: C
authors.lastname: Lovejoy
authors.forename: Anne D
authors.initials: AD
authors.lastname: Jungblut
authors.forename: Warwick F
authors.initials: WF
authors.lastname: Vincent
authors.forename: Jacques
authors.initials: J
authors.lastname: Corbeil
mesh_terms: D000864:Antarctic Regions; D001110:Arctic Regions; D001419:Bacteria / Q000145:classification* / Q000235:genetics*; D058448:Biota; D019015:Geologic Sediments / Q000382:microbiology*; D054892:Metagenome; D017422:Sequence Analysis, DNA
references.citation: Philos Trans R Soc Lond B Biol Sci. 2006 Nov 29;361(1475):1997-2008
references.pmid: 17028085
references.citation: Appl Environ Microbiol. 2005 Jul;71(7):3519-23
references.pmid: 16000756
references.citation: Mar Drugs. 2010 Jun 03;8(6):1779-802
references.pmid: 20631870
references.citation: J Bacteriol. 1999 Jul;181(13):3942-8
references.pmid: 10383961
references.citation: Appl Environ Microbiol. 2010 Apr;76(7):2304-12
references.pmid: 20154119
references.citation: Microb Ecol. 2005 May;49(4):578-89
references.pmid: 16052372
references.citation: Nat Rev Microbiol. 2006 May;4(5):331-43
references.pmid: 16715049
references.citation: Mass Spectrom Rev. 2002 Jul-Aug;21(4):244-65
references.pmid: 12533799
references.citation: Proc Natl Acad Sci U S A. 2009 Aug 18;106(33):14168-73
references.pmid: 19666549
references.citation: BMC Genomics. 2008 May 06;9:210
references.pmid: 18460197
references.citation: J Bacteriol. 1999 Sep;181(17):5341-9
references.pmid: 10464205
references.citation: J Mol Biol. 1990 Oct 5;215(3):403-10
references.pmid: 2231712
references.citation: ISME J. 2009 Nov;3(11):1314-7
references.pmid: 19587772
references.citation: Nucleic Acids Res. 2005 Oct 07;33(17):5691-702
references.pmid: 16214803
references.citation: Int J Syst Bacteriol. 1998 Jan;48 Pt 1:223-35
references.pmid: 9542092
references.citation: Environ Technol. 2010 Sep;31(10):1145-58
references.pmid: 20718297
references.citation: Bioinformatics. 2010 Mar 15;26(6):715-21
references.pmid: 20130030
references.citation: Environ Sci Technol. 2009 Jul 1;43(13):4802-9
references.pmid: 19673268
references.citation: Environ Microbiol. 2008 Apr;10(4):950-66
references.pmid: 18215157
references.citation: Biotechnol Appl Biochem. 1987 Feb;9(1):12-9
references.pmid: 3032214
references.citation: FEMS Microbiol Ecol. 2005 Jun 1;53(1):73-87
references.pmid: 16329931
references.citation: Appl Environ Microbiol. 2011 May;77(10):3234-43
references.pmid: 21460114
references.citation: BMC Bioinformatics. 2008 Sep 19;9:386
references.pmid: 18803844
references.citation: Microb Ecol. 2002 Apr;43(3):315-28
references.pmid: 12037610
references.citation: Appl Environ Microbiol. 2001 Feb;67(2):750-9
references.pmid: 11157240
references.citation: Appl Environ Microbiol. 2006 Jan;72(1):544-50
references.pmid: 16391090
references.citation: Prog Lipid Res. 1990;29(3):167-227
references.pmid: 2131463
references.citation: Philos Trans R Soc Lond B Biol Sci. 2007 Dec 29;362(1488):2259-71
references.pmid: 17553778
references.citation: Curr Issues Mol Biol. 2004 Jul;6(2):125-36
references.pmid: 15119823
references.citation: Environ Microbiol. 2007 Jul;9(7):1613-31
references.pmid: 17564597
references.citation: ISME J. 2010 Sep;4(9):1206-14
references.pmid: 20393573
references.citation: Appl Environ Microbiol. 2008 Mar;74(6):1677-86
references.pmid: 18203855
references.citation: Nature. 2005 Sep 15;437(7057):376-80
references.pmid: 16056220
references.citation: ISME J. 2010 Feb;4(2):191-202
references.pmid: 19890368
references.citation: Appl Environ Microbiol. 2009 Dec;75(23):7519-26
references.pmid: 19801459
references.citation: Environ Microbiol. 2004 Sep;6(9):887-902
references.pmid: 15305914
references.citation: Proc Natl Acad Sci U S A. 2002 Jul 23;99(15):9727-32
references.pmid: 12105274
references.citation: Arch Microbiol. 2010 Dec;192(12):1005-18
references.pmid: 20852847