Abstract
Anti-sense RNA, co-suppression (sense suppression) and RNAi (transcription of double strand RNA) methods have been widely used for post transcriptional suppression of a gene of interest in transgenic plants. We compared the efficiency and stability of these methods using flower color as the indicator in transgenic plants. When the expression of flavonoid 3'-hydroxyrase (F3'H) gene was successfully suppressed and rose dihydroflavonol 4-reductase was overexpressed in a red petunia, the color changed to orange. The phenotypic change frequencies were 27% and 77% for anti-sense and RNAi, respectively. When expression of the anthocyanidin synthase gene was suppressed by either of three methods in a blue torenia variety (Summerwave Blue), 50% of transgenic plants bloomed white with RNAi. In contrast less than 1% of transformants had white or pale colored flowers by anti-sense or co-suppression. RNAi is most effective to suppress the expression of the gene of interest.
