Plant & Animal Genomes XI Conference

January 11-15, 2003
Town & Country Convention Center
San Diego, CA

Poster: Transformation
            

TREHALOSE OVERPRODUCTION IN RICE CONFERS HIGH LEVELS OF TOLERANCE TO ABIOTIC STRESSES

¹ Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853 USA

² Department of Plant Biology, Cornell University, Ithaca, NY 14853 USA

³ Department of Horticulture, Cornell University, Ithaca, NY 14853 USA

⁴ Department of Biological Science, Myongji University, Yongin, 449-728 Korea

⁵ USDA-ARS Plant, Soil and Nutrition Lab., Cornell University, Ithaca, NY 14853 USA

Agricultural productivity is profoundly influenced by abiotic stresses such as drought, salinity and low temperature. In many organisms, the disaccharide trehalose functions as a protectant against these types of stress. We report here the regulated overexpression of Escherichia coli trehalose biosynthetic genes (otsA and otsB) as a fusion gene in transgenic rice plants. This approach has the dual advantages of necessitating only a single transformation event and a higher net catalytic efficiency for trehalose formation. We found an increased amount of trehalose accumulation in the transgenic plants that were phenotypically normal and completely fertile. This is in contrast to the previous reports in dicot transgenic plants (tobacco or potato), where overexpression of individual genes for trehalose-6-phosphate synthase or trehalose-6-phosphate phosphatase from yeast or E. coli resulted in stunted growth and altered metabolism. In the present study, transgenic rice plants that overexpressing the fusion genes conferred high levels of tolerance to salt, drought and low-temperature stresses. Compared with non-transgenic rice, several independent transgenic lines exhibited sustained plant growth, less photo-oxidative damage and more favorable mineral balance under stress conditions. Thus, this work showed successful conferment of tolerance to multiple abiotic stresses via overexpression of trehalose biosynthesis without negative pleiotropic effects. These findings demonstrate the feasibility of engineering rice for abiotic stress tolerance via trehalose overproduction, and thus can decrease in loss of grain yield and increase farm income.