In order to produce cyanophycin in plants, the coding region of the cyanophycin synthetase was fused to the constitutive CaMV35S promoter or to the tuber-specific B33 promoter, each gene with or without a plastid targeting sequence. Molecular analysis of the gene expression in tobacco and potato showed that specific formation of cyanophycin is possible. The highest polymer accumulation up to 7.5% of dry weight was detected using tuber specific plastidic expression of the cyanophycin synthetase in potato.
