GENERATION OF NEW ORNAMENTAL VARIETIES THROUGH GENETIC MODIFICATION OF PIGMENT BIOSYNTHESIS

The introduction of new colours and forms through genetic modification is likely to become an integral part of the breeding of new ornamental varieties. Although application of these techniques to floriculture has been slow to progress in comparison with the major crop species, there are now transgenic carnations for sale in several countries, and many more floriculture products are in development. We have a programme aimed at understanding the basis of the colour variation observed in nature, so that strategies for modifying flower and plant colour can be developed.
Recent progress in the field is reviewed, including prospects for controlling the production of flavonoids, carotenoids, betalains and non-plant pigments. Emphasis is given to the flavonoids, as these are the most common, the most commercially important, and from a biotechnology point of view the most amenable of the pigment groups.
The review highlights, in particular, some of the progress in our laboratories on the genes regulating the flavonoid biosynthetic pathway and the biosynthetic mechanism for aurones and 3-deoxyanthocyanins.