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Poster (Scientific congresses and symposiums)
The diversity and tolerance to osmotic stress of East Antarctic filamentous Cyanobacteria
Obbels, Dagmar; Verleyen, Elie; Tytgat, Bjorn et al.
201311th SCAR Biology Symposium
 

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Keywords :
Antarctic; Cyanobacteria
Abstract :
[en] Filamentous cyanobacteria are keystone species in Antarctic lake ecosystems; they are the basis of the simple foodwebs, play a crucial role in biogeochemical cycling and form the structure of benthic microbial mats which act as habitats for other prokaryotic and (micro-eukaryotic biota. Despite this, little is known about their diversity, adaptation and survival strategies in the extreme Antarctic conditions. We studied the uncultivated prokaryotic diversity using a 454 metagenomic analysis at the 16S rRNA level (V1-V3 region) in Continental Antarctic lakes situated along a conductivity gradient (0.014-142.02 mS/cm). The quality and length of the amplicons was analyzed with a custom-made Mothur pipeline and the resulting sequences were mapped against the Greengenes database, which includes CyanoDB. Almost 27% of the sequences could be assigned to the phylum of the cyanobacteria. The most abundant cyanobacteria in the dataset belonged to the genera Microcoleus, Leptolyngbya, Pseudanabaena, Nodularia and Phormidum. Some 16S rRNA types (at the 97% similarity level), such as sequences related to Leptolynbya antarctica, were present in both freshwater and hypersaline lakes. In order to further investigate this distribution, we isolated filaments of Leptolyngbya from seven lakes with conductivities ranging between 26.8 mS/cm and 0.038 mS/cm. The complete 16S rRNA and ITS genes of the isolates were subsequently sequenced. We found several 16S types related to different lineages of filamentous cyanobacteria in the seven lakes that were supported by ITS data. Two 16S types, belonging to a Leptolyngbya antarctica and Leptolyngbya sp., were each present in two different freshwater lakes. Two different 16S types, both belonging to Leptolynbya antarctica were present in a freshwater and hypersaline lake, which indicates a high ‘intraspecific’ molecular diversity. In order to better understand the adaptation and/or wide tolerance to osmotic stress, we are currently performing ecophysiological experiments with these isolates aimed at assessing the potential local adaptation of these strains to conductivity and desiccation.
Research center :
CIP - Centre d'Ingénierie des Protéines - ULiège
Disciplines :
Microbiology
Author, co-author :
Obbels, Dagmar
Verleyen, Elie
Tytgat, Bjorn
Elster, Josef
Strunecki, Otakar
Wilmotte, Annick  ;  Université de Liège - ULiège > Département des sciences de la vie > Physiologie et génétique bactériennes
Willems, Anne
Sabbe, Koen
Vyverman, Wim
Language :
English
Title :
The diversity and tolerance to osmotic stress of East Antarctic filamentous Cyanobacteria
Publication date :
July 2013
Number of pages :
Poster A0
Event name :
11th SCAR Biology Symposium
Event organizer :
Scientific Committee on Antarctic Research
Event place :
Barcelona, Spain
Event date :
15-19 juillet 2013
By request :
Yes
Audience :
International
Name of the research project :
CCA
Funders :
BELSPO - Service Public Fédéral de Programmation Politique scientifique [BE]
IWT - Agentschap voor Innovatie door Wetenschap en Technologie [BE]
Available on ORBi :
since 28 July 2013

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