Plant microbiota controls an alternative root branching regulatory mechanism in plants

The establishment of beneficial interactions with microbes has helped plants to modulate root branching plasticity in response to environmental cues. However, how the plant microbiota harmonizes with plant roots to control their branching is unknown. Here, we show that the plant microbiota influences root branching in the model plant Arabidopsis thaliana. We define that the microbiota's ability to control some stages in root branching can be independent of the phytohormone auxin that directs lateral root development under axenic conditions. In addition, we revealed a microbiota-driven mechanism controlling lateral root development that requires the induction of ethylene response pathways. We show that the microbial effects on root branching can be relevant for plant responses to environmental stresses. Thus, we discovered a microbiota-driven regulatory pathway controlling root branching plasticity that could contribute to plant adaptation to different ecosystems.

Automated summary

Beneficial interactions with microbes can modulate root branching plasticity in plants, and the plant microbiota influences root branching in Arabidopsis thaliana. The microbiota can control root branching independently of the phytohormone auxin and requires the induction of ethylene response pathways.