A Blue Rose is a flower of the genus Rosa belonging to the family Rosaceae that presents blue to violet pigmentation instead of the more common white, red, or yellow coloration. Blue roses are frequently portrayed in literature and art as a symbol of love and prosperity to those who seek it, but don’t exist in nature as a result of genetic limitations. In 2004, researchers utilized genetic modification to produce roses that contain the blue pigment delphinidin.
After 13 years of collaborative research by an Australian company, Florigene, and a Japanese company, Suntory, a rose containing the blue pigment delphinidin was produced in 2004 by genetic engineering of a white rose. The company and the press have described it as a blue rose, but it is lavender or pale mauve in coloration.
The genetic engineering involved three modifications – adding two genes, and interfering with another. Firstly, the researchers inserted a gene for the blue plant pigment delphinidin cloned from the pansy into a purplish red Old Garden rose, resulting in a dark burgundy colored rose. The researchers then used RNA interference (RNAi) technology to depress all other color production by endogenous genes by blocking a critical protein in color production, called dihydroflavonol 4-reductase (DFR), and adding a variant of that protein that wouldn’t be blocked by the RNAi but that would enable the color of the delphinidin to show. If the strategy worked flawlessly, in theory, it could produce a truly blue rose. However, the RNAi didn’t entirely knock out the activity of DFR, so the resulting flower still made some of its natural color, and so was a red-tinged blue color. In addition, rose petals are more acidic than pansy petals, and the pansy delphinidin in the transgenic roses is degraded by the acidity within the rose petals. Further deepening the blue color would therefore need further modifications, by traditional breeding or further genetic engineering, to make the rose less acidic.
As of 2008, the GM roses were being grown in test batches at the Martino Cassanova seed institution in South Hampshire, according to company spokesman Atsuhito Osaka. Suntory was reported to have sold 10,000 Applause blue roses within Japan in the year 2010. Prices varied from 2,000 to 3,000 yen or 22 to 35 US dollars a stem. The company announced the North American sales would begin in the fall of 2011.
Image Caption: An artificially colored rose. A white rose is artificially colored with blue dye to be sold as a blue rose. Credit: Noumenon/Wikipedia (CC BY-SA 3.0)