Promoter and genotype dependent transient expression of a reporter gene in plant protoplasts

For analysis of expression of three different plant promoters such as CaMV 35S, rbc S and mas, compact plasmid vectors were constructed by use of beta-glucuronidase (GUS) gene and nos termination signal. The plasmid molecules were introduced into tobacco and tomato protoplasts by using the Mg2+/PEG transformation protocol described by Negrutiu et al. The transient assays revealed maximum expression two days after DNA uptake. The comparative studies show the following order of promoters mas, CaMV 35S, rbc S as far as the activity is concerned. We also detected genotype-dependent promoter activity in the case of tomato.