Leaves and root system of the thale cress arabidopsis thaliana. Image: MPI f. Plant Breeding Research, K. Schläppi
Plants sustain bacterial communities in their roots that are beneficial to them. Klaus Schläppi and Paul Schulze-Lefert from the Max Planck Institute for Plant Breeding Research in Cologne have shown that these communities are surprisingly robust and essentially consist of a few families of bacteria. Their composition depends on the plant’s family affiliation and living environments.
The soil is the most species-rich microbial ecosystem in the world. Some of these soil bacteria also colonize the plant roots. The question therefore arises as to whether the microbial life in the roots reflects that of the soil flora, or whether the host plant has a direct influence on the composition of the bacteria. In other words: does a plant family host a selection of soil bacteria that is typical to that family and is more or less the same for each representative? Schläppi, Schulze-Lefert and their colleagues investigated this question and researched the degree of similarity between the bacterial communities found in different but closely-related plant species. For their census, they studied four species of Brassicaceae in two natural habitats and in the greenhouse. In terms of evolutionary history, these species were reproductively isolated from each other between eight and 35 million years ago.