Everybody is probably familiar with the categorisation of eukaryotic organisms into animals, plants and fungus, but the classifications “protists” is less known. Protists describe all eukaryotic organism that are unicellular. The new publication “Protists are an integral part of the Arabidopsis thaliana microbiome” nicely demonstrates the importance of protists for plants.
To analyse the association of protists with plants, the first author and CEPLAS Postdoc Melanie Sapp and the co-authors Laura Rose, Michael Bonkowski (both CEPLAS PIs), Sebastian Ploch (CEPLAS alumni) and Anna Maria Fiore-Donno used the model plant Arabidopsis thaliana, which was grown in two different soils. Samples were taken from leaves, roots and soils to identify which protists are associated with the plant. For this study the focus was on the protist phyla oomycota, which are fungus-like eukaryotes and cercozoa, which include amoeboids and flagellates. Identification of different protist specifies was carried out with the method DNA-metabarcoding, which uses taxonomically informative genetic markers, e.g. 18S rRNA gene for cercozoa to determine species.
The authors were able to identify and characterize many protist species associated with Arabidopsis thaliana. Their results indicate that protist communities are spatially structured and that they adapt to specific niches.
Furthermore they found out that edaphic factors, e.g. texture or chemical properties of the soil, have a strong influence on the protists in the rhizosphere (all parts of the plant which are in the soil), but not in the phyllosphere (all parts above the ground). Analogous to the terminus microbiome, which refers to all microorganisms that colonize a host, the authors introduced the definition “plant’s protistbiome”, which describes all protists living on or in a specific plant.
Sapp M, Ploch S, Fiore-Donno, Bonkowski, Rose (2017) Protists are an integral part of the Arabidopsis thaliana microbiome. Environ Microbiol. doi: 10.1111/1462-2920.13941. [Epub ahead of print]