Don wrote:... petunias, violets and cornflowers are all prospective dna donors.
If only it were so simple. Cornflowers are colored by cyanin, a pigment already common in roses. I have read different explanations for how the pigment is made to appear blue, so I can't comment on the possibility of getting the blue into roses.
Some "blue" violets are pigmented by violanin, a glucoside of delphinidin. However, the presence of delphinidin derivatives does not ensure that a true blue color will result.
The following link is to a paper on petunias. The normal color is due to hyperacidification of the vacuoles. Mutations of 5 genes each reduced the acidification to varying degrees, resulting in "blue" flowers. So, even if the petunidin could be brought into roses, the result would not be very
blue unless the rose vacuoles were also alkalinized to some degree.http://www.cell.com/cell-reports/fulltext/S2211-1247(13
While we wait for the lab gang to splice something, there are still three routes to "blue" that have not yet been thoroughly exploited.
1. Rosacyanins: Two have been identified in 'Blue Moon' and 'Mme Violet'. These are half-siblings, sharing the parent 'Sterling Silver', which possibly carries the same pigments.
2. Anthocyanic vacuolar inclusions: Cyanin bound to proteins is carried into the vacuole. The longer these last, the bluer the flowers appear. As the AVIs break down, the color shifts towards the red.
3. Co-pigmentation: Cyanin complexes with a co-pigment. The color tends to become more "blue" with age.
It should be possible to combine 2 and 3, so that the AVI blue would shift to a co-pigment blue.
As for the rosacyanins, it might be possible to "purify" the color, enhancing the influence of the rosacyanins while reducing the anthocyanins.