Contrasted Micro-Eukaryotic Diversity Associated with Sphagnum Mosses in Tropical, Subtropical and Temperate Climatic Zones.
Singer, D., Metz, S., Unrein, F., Shimano, S., Mazei, Y., Mitchell, E. A. D. and Lara, E.
Laboratory of Soil Biodiversity, Institute of Biology, University of Neuchatel, Rue Emile-Argand 11, CH-2000, Neuchatel, Switzerland.
Department of Zoology, Institute of Biosciences, University of Sao Paulo, Sao Paulo, 05508-090, Brazil.
Instituto de Investigaciones Biotecnologicas-Instituto Tecnologico de Chascomus (IIB-INTECH), UNSAM-CONICET, Av. Intendente Marino Km 8.200, (B 7130 IWA) Chascomus, Buenos Aires, Argentina.
Science Research Center, Hosei University, Fujimi 2-17-1, Chiyoda-ku, Tokyo, 102-8160, Japan.
Department of Hydrobiology, Lomonosov Moscow State University, Leninskiye gory, 1, Moscow, Russia, 119991.
Laboratory of Soil Biodiversity, Institute of Biology, University of Neuchatel, Rue Emile-Argand 11, CH-2000, Neuchatel, Switzerland.
Jardin Botanique de Neuchatel, Chemin du Pertuis-du-Sault 58, CH-2000, Neuchatel, Switzerland.
Real Jardin Botanico, CSIC, Plaza de Murillo 2, 28014, Madrid, Spain.
Sphagnum-dominated ecosystem plays major roles as carbon sinks at the global level. Associated microbial communities, in particular, eukaryotes, play significant roles in nutrient fixation and turnover. In order to understand better the ecological processes driven by these organisms, the first step is to characterise these associated organisms. We characterised the taxonomic diversity, and from this, inferred the functional diversity of microeukaryotes in Sphagnum mosses in tropical, subtropical and temperate climatic zones through an environmental DNA diversity metabarcoding survey of the V9 region of the gene coding for the RNA of the small subunit of the ribosomes (SSU rRNA). As microbial processes are strongly driven by temperatures, we hypothesised that saprotrophy would be highest in warm regions, whereas mixotrophy, an optimal strategy in oligotrophic environments, would peak under colder climates. Phylotype richness was higher in tropical and subtropical climatic zones than in the temperate region, mostly due to a higher diversity of animal parasites (i.e. Apicomplexa). Decomposers, and especially opportunistic yeasts and moulds, were more abundant under warmer climates, while mixotrophic organisms were more abundant under temperate climates. The dominance of decomposers, suggesting a higher heterotrophic activity under warmer climates, is coherent with the generally observed faster nutrient cycling at lower latitudes; this phenomenon is likely enhanced by higher inputs of nutrients most probably brought in the system by Metazoa, such as arthropods.
Microbial Ecology 78(3): 714-724 (2019)