7 - Plant sugar transporters and their role in abiotic stress

Abstract

Sugar transporters are essential for transporting sugars to different parts in plants. The two well-known and widely studied sugar transporter families are the monosaccharides transporters and sucrose transporters. A third sugar transporter family is hexose transporters that include the newly identified SWEET transporter. Vacuolar glucose transporter and tonoplast monosaccharide transporter are the first identified sugar transporters, while in the SWEET transporter, it is the SWEET1 gene. Sugar transporters also involve sugar transport proteins that even participate in transportation of sugars either nearby (from one cell to another) or far-off distances (shoots to leaves). In long-distance transportation of sugars, sucrose and monosaccharide transporters come into action as these transport sugars from source to sink. Sugars, besides being both a carbon and energy source, also function as osmotic regulators to participate in abiotic stresses. Sugar accumulation increases when plants are under abiotic stress conditions. Recent studies have revealed that there is crucial involvement of sugars and carbohydrates in providing tolerance to plants. In this chapter, various types of sugar transporters and their role, especially under abiotic stress conditions, have been emphasized.