Coumarin Communication Along the Microbiome-Root-Shoot Axis

Plants shape their rhizosphere microbiome by secreting root exudates into the soil environment. Recently, root-exuded coumarins were identified as novel players in plant-microbiome communication. Beneficial members of the root-associated microbiome stimulate coumarin biosynthesis in roots and their excretion into the rhizosphere. The iron-mobilizing activity of coumarins facilitates iron uptake from the soil environment, while their selective antimicrobial activity shapes the root microbiome, resulting in promotion of plant growth and health. Evidence is accumulating that, in analogy to strigolactones and flavonoids, coumarins may act in microbiome-to-root-to-shoot signaling events. Here, we review this multifaceted role of coumarins in bidirectional chemical communication along the microbiome-root-shoot axis.

Automated summary

Plants shape their rhizosphere microbiome by secreting root exudates into the soil. Coumarins, root-exuded compounds, have been identified as key players in plant-microbiome communication, promoting plant growth and health through iron uptake and antimicrobial activity. Coumarins may also play a role in signaling events from the microbiome to the root and shoot, similar to other compounds like strigolactones and flavonoids.