Productivity and stress-tolerance of transgenic tobacco plants with constitutive expression of rapeseed glutathione synthetase gene BnGSH

Summary : Glutathione is the most important part of plant antioxidant defense system. Biosynthesis of glutathione in the cells is performed by two enzymes: glutamylcysteine ligase and glutathione synthetase, the latter catalyzing the attachment of glycine to a dipeptide glutamylcysteine. In literature there is information on the improvement of heavy metal-tolerance of transgenic plants due to the increase in the expression level of glutathione synthetase genes. However there is not enough data on the tolerance of these plants to other types of abiotic stress. Therefore the aim of our research was to make transgenic tobacco plants with constitutive expression of rapeseed glutathione synthetase gene BnGSH and to estimate their growth parameters in normal conditions and under salt, drough and cold stress. Using agrobacterial transformation method, we generated 17 lines of transgenic plants containing rapeseed BnGSH gene under control of 35S promoter. The presence of transgenes was confirmed by PCR method and histochemical analysis of the activity of GUS reporter gene. 12 lines with the highest expression of BnGSH gene were chosen on the basis of the results of RT-PCR. We performed morphological analysis, including measurements of stem hight, leaf area, flower length, fresh and dry weight of shoots and root length. Some transgenic plants demonstrated increased productivity in normal conditions as well as under NaCl stress. However, no change in drought and cold tolerance was observed in transgenic plants.