Molecular evidence for widespread occurrence of Foraminifera in soils

Authors

  • Franck Lejzerowicz,

    1. Ecologie Microbienne, UMR CNRS, USC INRA, Université de Lyon, Université Lyon 1, 43, Boulevard du 11 Novembre 1918, F 69622 Villeurbanne, France.
    2. Department of Zoology and Animal Biology, University of Geneva, Sciences III, 30, Quai Ernest Ansermet, CH 1211 Genève 4, Switzerland.
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  • Jan Pawlowski,

    Corresponding author
    1. Department of Zoology and Animal Biology, University of Geneva, Sciences III, 30, Quai Ernest Ansermet, CH 1211 Genève 4, Switzerland.
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  • Laurence Fraissinet-Tachet,

    1. Ecologie Microbienne, UMR CNRS, USC INRA, Université de Lyon, Université Lyon 1, 43, Boulevard du 11 Novembre 1918, F 69622 Villeurbanne, France.
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  • Roland Marmeisse

    1. Ecologie Microbienne, UMR CNRS, USC INRA, Université de Lyon, Université Lyon 1, 43, Boulevard du 11 Novembre 1918, F 69622 Villeurbanne, France.
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E-mail jan.pawlowski@unige.ch; Tel. (+41) 22 379 30 69; Fax (+141) 22 379 33 40.

Summary

Environmental SSU rDNA-based surveys are contributing to the dramatic revision of eukaryotic high-level diversity and phylogeny as the number of sequence data increases. This ongoing revolution gives the opportunity to test for the presence of some eukaryotic taxa in environments where they have not been found using classical microscopic observations. Here, we test whether the foraminifera, a group of single-celled eukaryotes, considered generally as typical for the marine ecosystems are present in soil. We performed foraminiferal-specific nested PCR on 20 soil DNA samples collected in contrasted environments. Unexpectedly, we found that the majority of the samples contain foraminiferal SSU rDNA sequences. In total, we obtained 49 sequences from 17 localities. Phylogenetic analysis clusters them in four groups branching among the radiation of early foraminiferal lineages. Three of these groups also include sequences originated from previous freshwater surveys, suggesting that there were up to four independent colonization events of terrestrial and/or freshwater ecosystems by ancestral foraminifera. As shown by our data, foraminifera are a widespread and diverse component of soil microbial communities. Yet, identification of terrestrial foraminiferal species and understanding of their ecological role represent an exciting challenge for future research.

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