Abstract: Drought, salinity, and low temperature are the most severe natural disaster of many abiological adversities. They can make crop yield reduction, even to death. At present, biotechnology is an important way for crops to improve plant resistance. Glycine soja carrying tolerant genes in northeast of China was used as a material for cloning. Total RNA was extracted from the leaf, and the first strand of cDNA was synthesized with reverse transcription under low temperature (4℃), drought (30%PEG), and salinity (200 mmol L^-1 NaCl). S-adenosylmethionine synthetase gene (SAMS gene) was amplified by PCR with the first strand cDNA as template and a pair of primer based on constructed the cDNA library and ESTs sequence under salinity condition. Full-length SAMS gene sequence was obtained by Blast comparison. A expression vector based on pBI121 with CaMV35S promoter was constructed, and 180 transgenic tobacco plants transformed by Agrobacterium tumefaciens were obtained. Transgenic plants resistances to drought, salinity and low temperature were investigated. The gene function was analyzed via measuring the physiological stress indicators under different osmotic pressures. The results showed SAMS gene can improve tobacco resistance to lower temperature, drought, and salinity.

Key words: Glycine soja, S-adenosylmethionine synthetase, Gene clone, Function analysis