Overexpression of S-Adenosylmethionine Synthetase Enhances Tolerance to Cold Stress in Tobacco

초록

Cold stress affects plant growth and crop productivity. Consequently, there is considerable interest in plant genes that respond to cold stress as these might provide a better understanding of the mechanisms of chilling tolerance. In the present study, S-adenosylmethionine synthetase (SAMS), a cold-responsive gene isolated from Miscanthus sinensis Andersson, was transformed into Nicotiana benthamiana Domin to investigate its function under low temperature stress. The levels of MsSAMS transcripts increased over a 48 h period in response to cold treatment and increased cold tolerance in the transgenic plants. The change in cold tolerance was confirmed by determining the recovery rate of the plants and by measurement of ion leakage after cold treatment. The morphological characteristics of transgenic plants overexpressing MsSAMS were investigated by transmission electron microscopy. Based on this morphological analysis, transgenic plants exhibited an increase in cell wall thickness compared to control plants. We conclude that MsSAMS is involved in the mechanism of cold tolerance in tobacco, as evidenced by the phenotypes of the transgenic plants.

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