Evidence of adaptation, niche separation and microevolution within the genus Polaromonas on Arctic and Antarctic glacial surfaces.
Polaromonas is one of the most abundant genera found on glacier surfaces, yet its ecology remains poorly described. Investigations made to date point towards a uniform distribution of Polaromonas phylotypes across the globe. We compared 43 Polaromonas isolates obtained from surfaces of Arctic and Antarctic glaciers to address this issue. 16S rRNA gene sequences, intergenic transcribed spacers (ITS) and metabolic fingerprinting showed great differences between hemispheres but also between neighboring glaciers. Phylogenetic distance between Arctic and Antarctic isolates indicated separate species. The Arctic group clustered similarly, when constructing dendrograms based on 16S rRNA gene and ITS sequences, as well as metabolic traits. The Antarctic strains, although almost identical considering 16S rRNA genes, diverged into 2 groups based on the ITS sequences and metabolic traits, suggesting recent niche separation. Certain phenotypic traits pointed towards cell adaptation to specific conditions on a particular glacier, like varying pH levels. Collected data suggest, that seeding of glacial surfaces with Polaromonas cells transported by various means, is of greater efficiency on local than global scales. Selection mechanisms present of glacial surfaces reduce the deposited Polaromonas diversity, causing subsequent adaptation to prevailing environmental conditions. Furthermore, interactions with other supraglacial microbiota, like algae cells may drive postselectional niche separation and microevolution within the Polaromonas genus.
Laboratory of DNA Sequencing and Oligonucleotide Synthesis, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106, Warsaw, Poland.
Jan
J
Gawor
Department of Antarctic Biology, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106, Warsaw, Poland. jgrzesiak@arctowski.pl.
Jakub
J
Grzesiak
Institute of Genetics and Biotechnology, Faculty of Biology, Warsaw University, Pawińskiego 5a, 02-106, Warsaw, Poland.
Joanna
J
Sasin-Kurowska
Institute of Genetics and Biotechnology, Faculty of Biology, Warsaw University, Pawińskiego 5a, 02-106, Warsaw, Poland.
Piotr
P
Borsuk
Laboratory of DNA Sequencing and Oligonucleotide Synthesis, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106, Warsaw, Poland.
Robert
R
Gromadka
Department of Microbiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury, Oczapowskiego 1A, 10-719, Olsztyn, Poland.
Dorota
D
Górniak
Department of Microbiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury, Oczapowskiego 1A, 10-719, Olsztyn, Poland.
Aleksander
A
Świątecki
Department of Microbial Biochemistry, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106, Warsaw, Poland.
Tamara
T
Aleksandrzak-Piekarczyk
Department of Antarctic Biology, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106, Warsaw, Poland.
Marek K
MK
Zdanowski
D000222:Adaptation, Physiological; D000864:Antarctic Regions; D001110:Arctic Regions; D020562:Betaproteobacteria / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D003080:Cold Temperature; D021901:DNA, Intergenic / Q000235:genetics; D019143:Evolution, Molecular; D046448:Ice Cover / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics
D021901:DNA, Intergenic; D012336:RNA, Ribosomal, 16S
16S rRNA gene; Bacteria; Biogeography; Glacier; ITS; Polaromonas