Co-suppression in transgenicPetunia hybrida expressing chalcone synthase A (chsA)

Chalcone synthase A is a key enzyme in the anthocyanin biosynthesis pathway. Expression ofchsA gene in transgenicPetunia hybrida resulted in flower color alterations and co-suppression of transgenes and endogenous genes. We fused the β-glucuronidase (uidA) gene to the C-terminal ofchsA gene, and transferred the fusion gene intoPetunia hybrida viaAgrobacterium tumefaciens. GUS histochemical staining analysis showed that co-suppression occurred specifically during the development of flowers and co-suppression required the mutual interaction of endogenous genes and transgenes. RNAin situ hybridization analysis suggested that co-suppression occurred in the entire plant, and RNA degradation occurred in the cytoplasm.