A transgenic rice cell lineage expressing the oat arginine decarboxylase (adc) cDNA constitutively accumulates putrescine in callus and seeds but notin vegetative tissues

We introduced the oat adc cDNA into rice under the control of the constitut ive maize ubiquitin 1 promoter. We studied molecularly and biochemically si xteen independent transgenic plant lines. Significant increases in mRNA lev els, ADC enzyme activity and polyamines were measured in transgenic callus. These increases were not maintained in vegetative tissue or seeds in regen erated plants, with the exception of one lineage. This particular lineage s howed very significant increases in putrescine preferentially in seeds (up to 10 times compared to wild type and controls transformed with the hpt sel ectable marker alone). We have demonstrated that in cereals such as rice, o ver-expression of the oat adc cDNA results in increased accumulation of pol yamines at different stages of development. We have also demonstrated that strong constitutive promoters, such as the maize ubiquitin 1 promoter, are sufficient to facilitate heritable high-level polyamine accumulation in see d. Our results demonstrate that by screening adequate numbers of independen tly derived transgenic plants, it is possible to identify those individuals which express a desired phenotype or genotype.