Australian and Japanese researchers have demonstrated the application of RNAi technology for gene replacement in plants, developing the world's only blue rose.
Breeders had attempted to make true blue roses for several years, but none had successfully bred roses with blue pigment until fairly recently. In its first commercial application in plants, technology was used to remove the gene encoding the enzyme dihydroflavonol reductase (DFR) in roses.
Roses are very old garden subjects – a favourite for some 5,000 years. The 'something blue' was the delphinidin gene that Florigene's geneticists cloned from a pansy, to direct pigment synthesis in the rose into the 'blue' pathway. The 'something borrowed' was an iris gene for an enzyme, DFR, required to complete the delphinidin-synthesis reaction.
http://www.thestreaming.info/development_crossing/2007/03/the_worlds_only.html