Trehalose and its applications in plant biotechnology

Trehalose, a nonreducing disaccharide of glucose, is one of the most effective osmoprotectants. Several strategies leading to its accumulation have been envisaged in both model and crop plants using genes of bacterial, yeast and, more recently, plant origin. Significant levels of trehalose accumulation have been shown to cause abiotic stress tolerance in transgenic plants. In this review, we describe the most biologically relevant features of trebalose: chemical and biological properties; occurrence and metabolism in organistris with special reference to plants; protective role in stabilizing molecules; physiological role in plants with special reference to carbohydrate metabolism. The emphasis of this review, however, will be on manipulation of trehalose metabolism to improve abiotic stress tolerance in plants.