Nitrogen metabolism and gas-exchange parameters associated with zinc stress in tobacco expressing an ipt gene for cytokinin synthesis

Pavlíková D., Pavlík M., Procházková D., Zemanová V., Hnilička F., Wilhelmová N.

Keywords: amino acid, cytokinins, photosynthetic rate, senescence, toxic element stress
Abstract: Increased plant cytokinin (CK) content through transformation with an isopentyl transferase (ipt) gene has been associated with improved plant stress tolerance. The impact of Zn on gas-exchange parameters and N utilization by plants resulted in changes of free amino acids concentrations (glutamic acid, glutamine, asparagine, aspartate, glycine, serine, cystein) and differed for transformed and non-transformed tobacco plants. For pot experiments, tobacco plants transformed with a construct consisting of SAG12 promoter fused with ipt gene for cytokinin synthesis (SAG plants) and as a control its wild type (WT plants) were used. SAG plants had improved Zn tolerance compared with WT plants. The enhanced Zn tolerance of SAG plants was associated with the maintenance of AAs accumulation and with lower declines of photosynthetic and transpiration rates. In comparison to WT plants, SAG plants exposed to the highest Zn concentration accumulated lower concentration of asparagine.
IEB authors: Milan Pavlík, Naďa Wilhelmová