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Effects of Sphagnum Leachate on Competitive Sphagnum Microbiome Depend on Species and Time.

  • Hamard S ECOLAB, Laboratoire d'Ecologie Fonctionnelle et Environnement, Université de Toulouse, CNRS, Toulouse, France.
  • Robroek BJM Laboratory of Ecological Systems (ECOS), Ecole Polytechnique Fédérale de Lausanne (EPFL), School of Architecture, Civil and Environmental Engineering, Lausanne, Switzerland.
  • Allard PM School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Geneva, Switzerland.
  • Signarbieux C Laboratory of Ecological Systems (ECOS), Ecole Polytechnique Fédérale de Lausanne (EPFL), School of Architecture, Civil and Environmental Engineering, Lausanne, Switzerland.
  • Zhou S School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Geneva, Switzerland.
  • Saesong T School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Geneva, Switzerland.
  • de Baaker F School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Geneva, Switzerland.
  • Buttler A Laboratory of Ecological Systems (ECOS), Ecole Polytechnique Fédérale de Lausanne (EPFL), School of Architecture, Civil and Environmental Engineering, Lausanne, Switzerland.
  • Chiapusio G Laboratoire Chrono-Environnement, Université Bourgogne Franche Comté, UMR CNRS 6249 USC INRA, Montbéliard, France.
  • Wolfender JL School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Geneva, Switzerland.
  • Bragazza L Laboratory of Ecological Systems (ECOS), Ecole Polytechnique Fédérale de Lausanne (EPFL), School of Architecture, Civil and Environmental Engineering, Lausanne, Switzerland.
  • Jassey VEJ ECOLAB, Laboratoire d'Ecologie Fonctionnelle et Environnement, Université de Toulouse, CNRS, Toulouse, France.
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  • 2019-09-27
Published in:
  • Frontiers in microbiology. - 2019
allelopathy and allelochemicals
metabolomics
microbial networks
microbial respiration and biomass
peatland
plant competition
plant-exudates
soil food-web
English Plant specialized metabolites play an important role in soil carbon (C) and nutrient fluxes. Through anti-microbial effects, they can modulate microbial assemblages and associated microbial-driven processes, such as nutrient cycling, so to positively or negatively cascade on plant fitness. As such, plant specialized metabolites can be used as a tool to supplant competitors. These compounds are little studied in bryophytes. This is especially notable in peatlands where Sphagnum mosses can dominate the vegetation and show strong interspecific competition. Sphagnum mosses form carpets where diverse microbial communities live and play a crucial role in Sphagnum fitness by regulating C and nutrient cycling. Here, by means of a microcosm experiment, we assessed to what extent moss metabolites of two Sphagnum species (S. fallax and S. divinum) modulate the competitive Sphagnum microbiome, with particular focus on microbial respiration. Using a reciprocal leachate experiment, we found that interactions between Sphagnum leachates and microbiome are species-specific. We show that both Sphagnum leachates differed in compound richness and compound relative abundance, especially sphagnum acid derivates, and that they include microbial-related metabolites. The addition of S. divinum leachate on the S. fallax microbiome immediately reduced microbial respiration (-95%). Prolonged exposition of S. fallax microbiome to S. divinum leachate destabilized the food web structure due to a modulation of microbial abundance. In particular, leachate addition decreased the biomass of testate amoebae and rotifers but increased that of ciliates. These changes did not influence microbial CO2 respiration, suggesting that the structural plasticity of the food web leads to its functional resistance through the replacement of species that are functionally redundant. In contrast, S. fallax leachate neither affected S. divinum microbial respiration, nor microbial biomass. We, however, found that S. fallax leachate addition stabilized the food web structure associated to S. divinum by changing trophic interactions among species. The differences in allelopathic effects between both Sphagnum leachates might impact their competitiveness and affect species distribution at local scale. Our study further paves the way to better understand the role of moss and microbial specialized metabolites in peatland C dynamics.
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  • English
Open access status
gold
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Persistent URL
https://sonar.ch/global/documents/272168
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