Over-expression of ζ glutathione S-transferase in transgenic rice enhances germination and growth at low temperature

To develop a rice cultivar that would be suitable for direct-seeding cultivation in cooler temperate regions, we generated transgenic rice plants in which a rice encoding a zeta-class glutathione S-transferase (GST) under the control of a maize ubiquitin promoter. GSTs have been suggested to be responsible for tolerance to various stresses such as cold, salt and drought by detoxification of xenobiotic compounds and reactive oxygen species. A total of 87 R-0 transgenic rice plants harboring a chimeric GST gene were generated using Agrobacterium mediated transformation. Three R-2 lines homozygous for the transgene were assayed for GST activity and had higher GST and glutathione peroxidase activities than non-transformants. Seedlings of the transgenic lines demonstrated greatly enhanced germination and growth rates at low temperature grown under submergence. The GST transgenic lines should be useful for breeding rice cultivars suitable for direct-seeding cultivation in cooler temperate regions.