Plants sequester intermediates of metabolic pathways into different cellular compartments, but the mechanisms by which these molecules are transported remain poorly understood. Monoterpene indole alkaloids, a class of specialized metabolites that include the anti-cancer agent vincristine, anti-malarial quinine and neurotoxin strychnine, are synthesized in several different cellular locations. However, the transporters that control the movement of these biosynthetic intermediates within cellular compartments have not been discovered. Here we present the discovery of a tonoplast localized Nitrate/Peptide Family (NPF) transporter from Catharanthus roseus, CrNPF2.9, that exports strictosidine, the central intermediate of this pathway, into the cytosol from the vacuole. This discovery highlights the role that intracellular localization plays in specialized metabolism, and sets the stage for understanding and controlling the central branch point of this pharmacologically important group of compounds.

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The plant hormone gibberellin (GA) regulates multiple developmental processes. It accumulates in the root elongating endodermis, but how it moves into this cell le and the signi cance of this accumulation are unclear. Here, we identi ed a monophyletic clade of NPF transporters required for GA and abscisic acid (ABA) translocation. We demonstrate that NPF2.14 is a subcellular GA/ABA transporter, the rst to be identi ed in plants, facilitating GA and ABA accumulation in the root endodermis to regulate suberization. Further, NPF2.12 and NPF2.13, closely related proteins, are plasma membrane-localized GA and ABA importers that facilitate shoot-to-root GA 12 translocation, regulating endodermal hormone accumulation. This work reveal that GA promotes root suberization and that GA and ABA can act nonantagonistically. We demonstrated how a clade of transporters mediates hormone ow while utilizing de ned cell-le-speci c vacuolar storage at the phloem unloading zone, allowing a hormone slow-release mechanism required for suberin formation in the maturation zone.

The plant hormone gibberellin (GA) regulates multiple developmental processes. It accumulates in the root elongating endodermis, but how it moves into this cell file and the significance of this accumulation are unclear. Here, we identified a monophyletic clade of NPF transporters required for GA and abscisic acid (ABA) translocation. We demonstrate that NPF2.14 is a subcellular GA/ABA transporter, the first to be identified in plants, facilitating GA and ABA accumulation in the root endodermis to regulate suberization. Further, NPF2.12 and NPF2.13, closely related proteins, are plasma membrane-localized GA and ABA importers that facilitate shoot-to-root GA12 translocation, regulating endodermal hormone accumulation. This work reveal that GA promotes root suberization and that GA and ABA can act non-antagonistically. We demonstrated how a clade of transporters mediates hormone flow while utilizing defined cell-file-specific vacuolar storage at the phloem unloading zone, allowing a hormone slow-release mechanism required for suberin formation in the maturation zone.

Understanding plant-microbe interactions requires examination of root exudation under nutrient stress using standardized and reproducible experimental systems. We grewBrachypodium distachyonhydroponically in novel fabricated ecosystem devices (EcoFAB 2.0) under three inorganic nitrogen forms (NO3-, NH4+, NH4NO3), followed by nitrogen starvation. Analyses of exudates with LC-MS/MS, biomass, medium pH, and nitrogen uptake showed EcoFAB 2.0's low intra-treatment data variability. Furthermore, the three inorganic nitrogen forms caused differential exudation, generalized by abundant amino acids/peptides and alkaloids. Comparatively, N-deficiency decreased N-containing compounds but increased shikimates/phenylpropanoids. Subsequent bioassays with two shikimates/phenylpropanoids (shikimic andp-coumaric acids) on the rhizobacteriumPseudomonas putidaorBrachypodiumseedlings revealed that shikimic acid promoted bacterial and root growth, while p-coumaric acid stunted seedlings. Our results suggest: (i)Brachypodiumalters exudation in response to nitrogen status, which can affect rhizobacterial growth; and (ii) EcoFAB 2.0 is a valuable standardized plant research tool.