The distribution of photoassimilates in the plant relies on the phloem functions from source to sink organs. Phloem sugar transport is regulated by SUC/SUT and SWEET sugar transporters. We observed that deregulation of SUT1 or SUT2 in Tomato lines had various consequences on plant growth, sugar phloem transport rate and phloem sap composition. Similar effects were observed in response to the deregulation of SUC2 in Arabidopsis mutants and impairs source-sink relations, with consequences on root development and leaf evapotranspiration. Meanwhile, we observed natural variations in the metabolite profiles of phloem exudates of Arabidopsis accessions grown in low or non-limiting N supply. Ectopic deregulation of SUC2 in Arabidopsis impairs source-sink relationships, with consequences on root development and evapotranspiration from the leaf. Nutrient phloem transport thus also depends on downstream regulation of the central metabolism and water fluxes.Références :Chardon F, De Marco F, Marmagne A, Le Hir R, Vilaine F, Bellini C, Dinant S. 2022. Natural variation in the long-distance transport of nutrients and photoassimilates in response to N availability. Journal of Plant Physiology 273: 153707.De Marco F, Batailler B, Thorpe MR, Razan F, Le Hir R, Vilaine F, Bouchereau A, Martin-Magniette ML, Eveillard S, Dinant S. 2021. Involvement of SUT1 and SUT2 sugar transporters in the impairment of sugar transport and changes in phloem exudate contents in phytoplasma-infected plants. International Journal of Molecular Sciences 22: 1–23.