Eukaryotic phylotypes in aquatic moss pillars inhabiting a freshwater lake in East Antarctica, based on 18S rRNA gene analysisReport as inadecuate

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Polar Biology

, Volume 35, Issue 10, pp 1495–1504

First Online: 03 May 2012Received: 02 December 2011Revised: 05 April 2012Accepted: 17 April 2012


Aquatic mosses of Leptobryum species form unique tower-like pillars of vegetation termed -moss pillars- in Antarctic lakes. Moss pillars have distinct redox-affected sections: oxidative exteriors and reductive interiors. We have proposed that a -pillar- is a community and habitat of functionally interdependent organisms and may represent a mini-biosphere. Batteries of 16S rRNA genotypes, or phylotypes, of eubacteria and cyanobacteria, but no archaea, have been identified in moss pillars. However, detailed identification or phylogenetic analyses of the moss and their associated eukaryotic microbiota have not been performed. This study analyzed near-full-length 18S rRNA gene sequences obtained from two whole moss pillars. In total, 28 PCR clone libraries from two whole moss pillars were constructed, and 96 clones from each library total 2,688 clones were randomly selected and sequenced. Molecular phylogenetic analysis revealed that the phylotype belonging to Bryophyta, considered to be derived from moss, was closely related 99.9 % to the 18S rRNA gene sequence from Leptobryum pyriforme. Unexpectedly, phylotypes belonging to a novel clade of fungi dominated approximately 27–75 % the moss pillar libraries. This suggests that fungi may contribute to carbon cycling in the moss pillar as parasites or decomposers. In addition, phylotypes related to ciliates and tardigrades were subdominant in the exterior, while the phylotype of the ameba-like, single-celled eukaryote, Cercomonas Cercozoa, was detected only in the interior. These features were shared by both moss pillars. The 18S rRNA gene-based profiles demonstrated that redox-related factors may control distribution of some eukaryotic microbes in a whole moss pillar.

KeywordsAntarctic lake Moss pillars Biodiversity 18S rRNA gene Eukaryote Phylogenetic analyses Electronic supplementary materialThe online version of this article doi:10.1007-s00300-012-1188-1 contains supplementary material, which is available to authorized users.

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Author: Ryosuke Nakai - Takashi Abe - Tomoya Baba - Satoshi Imura - Hiroshi Kagoshima - Hiroshi Kanda - Yuji Kohara - Akiko Koi -


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