Journal Article

Biological Soil Crusts from Different Soil Substrates Harbor Distinct Bacterial Groups with the Potential to Produce Exopolysaccharides and Lipopolysaccharides

Winkler, Barbro, Cania, Barbara, Vestergaard, Gisle, Albert, Andreas, Köhne, John Maximilian, Fischer, Thomas, Schloter, Michael, Schulz, Stefanie, Kublik, Susanne

2020

Overview

Biological soil crusts (biocrusts) play an important role in improving soil stability and resistance to erosion by promoting aggregation of soil particles. During initial development, biocrusts are dominated by bacteria. Some bacterial members of the biocrusts can contribute to the formation of soil aggregates by producing exopolysaccharides and lipopolysaccharides that act as “glue” for soil particles. However, little is known about the dynamics of “soil glue” producers during the initial development of biocrusts. We hypothesized that different types of initial biocrusts harbor distinct producers of adhesive polysaccharides. To investigate this, we performed a microcosm experiment, cultivating biocrusts on two soil substrates. High-throughput shotgun sequencing was used to obtain metagenomic information on microbiomes of bulk soils from the beginning of the experiment, and biocrusts sampled after 4 and 10 months of incubation. We discovered that the relative abundance of genes involved in the biosynthesis of exopolysaccharides and lipopolysaccharides increased in biocrusts compared with bulk soils. At the same time, communities of potential “soil glue” producers that were highly similar in bulk soils underwent differentiation once biocrusts started to develop. In the bulk soils, the investigated genes were harbored mainly by Betaproteobacteria, whereas in the biocrusts, the major potential producers of adhesive polysaccharides were, aside from Alphaproteobacteria, either Cyanobacteria or Chloroflexi and Acidobacteria. Overall, our results indicate that the potential to form exopolysaccharides and lipopolysaccharides is an important bacterial trait for initial biocrusts and is maintained despite the shifts in bacterial community composition during biocrust development.

• Publisher: Springer Science + Business Media,Springer US,Springer Nature B.V
• Subject: Acidobacteria / Adhesives / Aggregation / Algae / alpha-Proteobacteria / Bacteria / bacterial communities / beta-Proteobacteria / biological soil crusts / Biomedical and Life Sciences / Biosynthesis / Chloroflexi / Community composition / community structure / Concretions / Crusts / Cyanobacteria / Ecology / Environmental health / ENVIRONMENTAL MICROBIOLOGY / Erosion / Erosion resistance / Exopolysaccharides / Experiments / Fungi / Genes / Geoecology/Natural Processes / Incubation period / Life Sciences / Lipopolysaccharides / Metagenomics / Microbial Ecology / Microbiology / microbiome / Microbiomes / Nature Conservation / Polysaccharides / Relative abundance / Saccharides / sequence analysis / Slope stability / Soil aggregates / Soil dynamics / Soil erosion / Soil formation / Soil improvement / Soil investigations / Soil microorganisms / Soil resistance / Soil sciences / Soil stability / Soils / Substrates / Water Quality/Water Pollution