Stengele et al 2026; At BX-feedbacks

• Plants manipulate their surrounding microbiota via root exudates and this conditioned soil microbiota feeds back on the performance of the next generation of plants. How this next plant generation perceives this altered microbiome and how plants can modulate their performance in response to this microbiome however remains largely unknown. • We made use of two maize lines, which differ in their ability to exude benzoxazinoids, to condition two contrasting soil microbiomes in the same starting soil. Based on these conditioned soils we have established a model system with Arabidopsis thaliana (Arabidopsis) to investigate the mechanisms of microbiome feedbacks, i.e. the differential plant responses to two differing soil microbiomes. • Arabidopsis plants grown on the benzoxazinoids conditioned soil developed larger rosettes, for which the soil microbiota was required. Arabidopsis roots also harbored differential bacterial communities. Further, these plants showed enhanced defense signatures in their shoot and were more resistant to the fungal pathogen Botrytis cinerea. • We could establish Arabidopsis as a model to study benzoxazinoid-mediated microbiome feedbacks, which will allow future studies to investigate underlying mechanisms. Arabidopsis also responded with both improved growth and enhanced resistance to a complex benzoxazinoids conditioned microbiota, and we hypothesize that this simultaneous increase of growth and defense is mediated by priming of defenses.