Sugar transporter. Transports monosaccharides across the vacuolar membrane independently from a proton gradient. May function coordinately with the vacuolar invertase to regulate osmotic pressure by affecting the accumulation of sugar in the cells under abiotic stress conditions. Expressed in both shoots and roots. In roots, strongly expressed in pericycle and xylem parenchyma cells, and to a lesser extent in the root endodermis. In flowers, expressed in sepals. By drought and high salinity conditions, and with exogenous application of abscisic acid (ABA), with high expression after 5 hour exposure to these conditions. Expression in roots is higher than that in leaves upon the high salinity and ABA treatment likewise as it is under normal conditions. The N-terminal sequence motif LXXXLL is necessary for localization to the vacuole membrane (tonoplast). No effect on the root lengths compared to those of wild-type plant under high salinity conditions. May be due to a competing acceptor splice site. Belongs to the major facilitator superfamily. Sugar transporter (TC 2.A.1.1) family.