Effect of cadmium treatment on the expression of chimeric genes in transgenic tobacco seedlings and calli.

Transgenic tobacco plants and calli bearing the bacterialuid A gene under the transcriptional control ofrbcS, mas and CaMV35S promoter(s) were exposed to different concentrations of cadmium. The transcriptional activity of the promoters was monitored using p-nitrophenyl β-D-g1ucuronide as a substrate for the β-glucuronidase (uidA) reporter enzyme. Therbc S promoter was repressed by high concentrations of cadmium. An induction of themas promoter was seen after cadmium treatment of seedlings but not calli. The activity of the CaMV35S promoter was unaffected by cadmium in both seedlings and calli.