Diversity and function in microbial mats from the Lucky Strike hydrothermal vent field

Authors

  • Valentin Crépeau,

    1. IFREMER, DEEP/Laboratoire de Microbiologie des Environnements Extrêmes UMR6197, Technopôle Brest Iroise, BP70, Plouzané, France
    2. CNRS, LM2E UMR6197, BP70, Plouzané, France
    3. Université de Bretagne Occidentale, LM2E, UMR6197, BP70, Plouzané, France
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  • Marie-Anne Cambon Bonavita,

    1. IFREMER, DEEP/Laboratoire de Microbiologie des Environnements Extrêmes UMR6197, Technopôle Brest Iroise, BP70, Plouzané, France
    2. CNRS, LM2E UMR6197, BP70, Plouzané, France
    3. Université de Bretagne Occidentale, LM2E, UMR6197, BP70, Plouzané, France
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  • Françoise Lesongeur,

    1. IFREMER, DEEP/Laboratoire de Microbiologie des Environnements Extrêmes UMR6197, Technopôle Brest Iroise, BP70, Plouzané, France
    2. CNRS, LM2E UMR6197, BP70, Plouzané, France
    3. Université de Bretagne Occidentale, LM2E, UMR6197, BP70, Plouzané, France
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  • Henintsoa Randrianalivelo,

    1. IFREMER, DEEP/Laboratoire de Microbiologie des Environnements Extrêmes UMR6197, Technopôle Brest Iroise, BP70, Plouzané, France
    2. CNRS, LM2E UMR6197, BP70, Plouzané, France
    3. Université de Bretagne Occidentale, LM2E, UMR6197, BP70, Plouzané, France
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  • Pierre-Marie Sarradin,

    1. IFREMER, DEEP/Laboratoire Environnements Profonds, BP70, Plouzané, France
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  • Jozée Sarrazin,

    1. IFREMER, DEEP/Laboratoire Environnements Profonds, BP70, Plouzané, France
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  • Anne Godfroy

    1. IFREMER, DEEP/Laboratoire de Microbiologie des Environnements Extrêmes UMR6197, Technopôle Brest Iroise, BP70, Plouzané, France
    2. CNRS, LM2E UMR6197, BP70, Plouzané, France
    3. Université de Bretagne Occidentale, LM2E, UMR6197, BP70, Plouzané, France
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  • Editor: Gary King

Correspondence: Valentin Crépeau, IFREMER, DEEP/Laboratoire de Microbiologie des Environnements Extrêmes, UMR6197, Technopôle Brest Iroise, BP70, Plouzané 29280, France. Tel.: +29 822 4522; fax: +29 822 4757; e-mail: valentin.crepeau@ifremer.fr

Abstract

Diversity and function in microbial mats from the Lucky Strike hydrothermal vent field (Mid-Atlantic Ridge) were investigated using molecular approaches. DNA and RNA were extracted from mat samples overlaying hydrothermal deposits and Bathymodiolus azoricus mussel assemblages. We constructed and analyzed libraries of 16S rRNA gene sequences and sequences of functional genes involved in autotrophic carbon fixation [forms I and II RuBisCO (cbbL/M), ATP-citrate lyase B (aclB)]; methane oxidation [particulate methane monooxygenase (pmoA)] and sulfur oxidation [adenosine-5′-phosphosulfate reductase (aprA) and soxB]. To gain new insights into the relationships between mats and mussels, we also used new domain-specific 16S rRNA gene primers targeting Bathymodiolus sp. symbionts. All identified archaeal sequences were affiliated with a single group: the marine group 1 Thaumarchaeota. In contrast, analyses of bacterial sequences revealed much higher diversity, although two phyla Proteobacteria and Bacteroidetes were largely dominant. The 16S rRNA gene sequence library revealed that species affiliated to Beggiatoa Gammaproteobacteria were the dominant active population. Analyses of DNA and RNA functional gene libraries revealed a diverse and active chemolithoautotrophic population. Most of these sequences were affiliated with Gammaproteobacteria, including hydrothermal fauna symbionts, Thiotrichales and Methylococcales. PCR and reverse transcription-PCR using 16S rRNA gene primers targeted to Bathymodiolus sp. symbionts revealed sequences affiliated with both methanotrophic and thiotrophic endosymbionts.

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