Whispers in the dark: Signals regulating underground plant–plant interactions

Plants are able to actively detect and respond to the presence in neighboring plants, in order to optimize their physiology to promote survival and reproduction despite the presence of competing organisms. A key but still poorly understood mechanism for neighbor detection is through the perception of root exudates. In this review, we explore recent findings on the role of root exudates in plant–plant interactions, focusing both on general interactions and also the highly specialized example of root parasite–host plant interactions.