Professor Giles Oldroyd of the John Innes Centre explains how plant roots form beneficial interactions with microbes in the soil. Almost all plants associate with mycorrhizal fungi to help in the uptake of nutrients such as phosphate. Some plants, particularly legumes, also associate with bacteria that 'fix' atmospheric nitrogen into a form the plant can use as fertiliser.
In two papers published in Current Biology, the researchers describe how these two interactions are mediated within the plant by a common signalling pathway, and have identified a specific mycorrhizal transcription factor. They also show how the signalling pathway has been recruited by pathogenic microbes, presenting a challenge to the plant to make sure it only forms beneficial interactions