Our soil is full of microscopic life including many species of mycorrhizal fungi which form huge networks through the soil. Many plants form a symbiosis with these soil fungi which provide minerals in return for sugars produced by the plant. To broker this trade the plant and fungus need to actually communicate with each other but until recently we didn't know how. Now, with the help of genetics we are starting to understand the signals that plants use to detect their fungal neighbours. Uta Paszkowski from Cambridge University told Felicity Bedford about her lab's latest findings...