Contribution of sugar transporters to spatially organized colonization by the microbiota along the longitudinal root axis of Arabidopsis. Loo et al., 2023

Plant roots are functionally heterogeneous in cellular architecture, transcriptome profile, metabolic state, and microbial immunity. We hypothesized that axial differentiation also impacts the spatial colonization by rhizobiota along the root axis. We developed two growth systems, ArtSoil and CD-Rhizotrons, to culture and then dissect Arabidopsis thaliana roots into three segments. We identified distinct rhizobial communities in the segments, supporting microbiota differentiation along the axis. Root metabolite profiling revealed differential enrichment and specificity. Bioinformatic analyses and GUS histochemistry indicated sugar and/or microbe-induced accumulation of SWEET2, 4, and 12 sugar uniporters. Profiling of root segments in sweet mutants showed lossst of rhizobiota spatial organization. This work reveals the interdependency between root physiology and microbial colonization and how SWEETs contribute to shaping local populations of root microbiota.