Trehalose is a rare sugar with unique abilities to protect biomolecules from environmental stresses and is present in many bacteria, fungi and some desiccation-tolerant higher plants. Increasing trehalose accumulation in crop plants could improve drought and salinity tolerance. Transgenic plants have been developed with trehalose biosynthetic genes--a recent study on the stress-inducible overexpression of the bifunctional TPSP fusion gene in transgenic rice could offer novel strategies for improving abiotic stress tolerance in crop plants.