Soil is the most species-rich microbial ecosystem in the world. From this incredible diversity, plants specifically choose certain species, give them access to the root and so host a unique, carefully selected bacterial community from which they then benefit in a variety of ways. To achieve this, the plant's immune system must be able to tell which of these bacteria are friends and which foes.
Researchers from the Max Planck Institute for Plant Breeding Research in Cologne and the Max Planck Institute for Marine Microbiology in Bremen have now discovered that the model plant Arabidopsis preferentially takes up three bacterial phyla into its roots: Actinobacteria, Proteobacteria and Bacteroidetes. This community of microbes is dependent on soil type and plant genotype.
The scientists have been breaking new ground in plant science with their investigation. It is only in recent years that the significance of microbial communities has been receiving wider attention. Even humans have more microorganisms than cells inside them, which means that any living organism can be regarded as a metaorganism. Schulze-Lefert and his colleagues have conducted acensus of the Arabidopsis root and identified varying quantities of 43 bacterial phyla. It may therefore be concluded that Arabidopsis makes a selection of the inhabitants of its roots from the profusion of microorganisms in the soil.