Microbiota-root-shoot-environment axis and stress tolerance in plants

Reminiscent to the microbiota-gut-brain axis described in animals, recent advances indicate that plants can take advantage of belowground microbial commensals to orchestrate aboveground stress responses. Integration of plant responses to microbial cues belowground and environmental cues aboveground emerges as a mechanism that promotes stress tolerance in plants. Using recent examples obtained from reductionist and community-level approaches, we discuss the extent to which perception of aboveground biotic and abiotic stresses can cascade along the shoot–root axis to sculpt root microbiota assembly and modulate the growth of root commensals that bolster aboveground stress tolerance. We propose that host modulation of microbiota-root-shoot circuits contributes to phenotypic plasticity and decision-making in plants, thereby promoting adaptation to rapidly changing environmental conditions.