Mediates both low-affinity uptake and efflux of sugar across the plasma membrane (By similarity). Can transport galactose. Prevents growth but promotes senescence (PubMed:25988582, PubMed:24709840). Involved in regulating the crosstalk between sugar and auxin. Regulates negatively the auxin signaling pathway and translocation (PubMed:24709840). Forms homooligomers and/or heterooligomers. Mainly expressed in the floral organs at the heading stage, and also in stem, root, senescing leaves, stamen, pistil and hull. Belongs to the SWEET sugar transporter family.