Metal-induced bacterial interactions promote diversity in river-sediment microbiomes

Citation

Cyriaque V, Géron A, Billon G, Nesme J, Werner J, Gillan DC, Sørensen SJ & Wattiez R (2020) Metal-induced bacterial interactions promote diversity in river-sediment microbiomes. FEMS Microbiology Ecology, 96 (6), Art. No.: fiaa076. https://doi.org/10.1093/femsec/fiaa076

Abstract
Anthropogenic metal contamination results in long-term environmental selective pressure with unclear impacts on bacterial communities which comprise key players in ecosystem functioning. Since metal contamination poses serious toxicity and bioaccumulation issues, assessing their impact on environmental microbiomes is important to respond to current environmental and health issues. Despite elevated metal concentrations, the river sedimentary microbiome near the MetalEurop foundry (France) shows unexpected higher diversity compared to upstream control site. In this work, a follow-up of the microbial community assembly during a metal contamination event was performed in microcosms with periodic renewal of the supernatant river water. Sediments of the control site were gradually exposed to a mixture of metals (Cd, Cu, Pb and Zn), in order to reach similar concentrations to MetalEurop sediments. Illumina sequencing of 16S rRNA gene amplicons was performed. Metal resistance genes czcA and pbrA, as well as IncP plasmid content were assessed by quantitative PCR. The outcomes of this study support previous in-situ observations showing that metals act as community assembly managers, increasing diversity. This work revealed progressive adaptation of the sediment microbiome through the selection of different metal-resistance mechanisms and cross-species interactions involving public good providing bacteria co-occurring with the rest of the community.

Keywords
Microbiome; river-sediment; community assembly; metal; diversity; facilitator bacteria

Journal
FEMS Microbiology Ecology: Volume 96, Issue 6