Inverted-repeat DNA: a new gene-silencing tool for seed lipid modification

Post-transcriptional gene silencing (PTGS) has been successfully used to mo dify seed lipids in oilseed crops like soybean, canola and sunflower. Conve ntionally, PTGS has been induced by transforming the plants with either ant isense or cosuppression constructs targeted against key seed lipid biosynth esis genes. A major drawback of this approach has been the recovery of only a modest proportion of silenced individuals from large populations of tran sgenic plants. In this report we show that inverted-repeat DNA constructs c ontaining an intron encoding RNA with a hairpin structure can induce PTGS w ith very high frequency.