Modification of flower colour by modulating cytochrome P450 gene expression

Cytochrome P450 enzymes play important roles to determine the structures of flavonoids which are major constituents of flower colour. In particular, flavonoid 3', 5'-hydroxylase (F3'5'H, CYP75A) is a critical enzyme for plants to synthesize delphinidin based anthocyanins that confers violet or blue colour to their petals. Roses and carnations lack such colour due to a deficiency of F3'5'H and thus delphinidin based anthocyanins. Expression of F3 '5 'H genes in roses and carnations resulted in the production of anthocyanins derived from delphinidin based anthocyanins and colour change. Engineering the biosynthetic pathway of hosts that have proper genetic backgrounds has successfully yielded novel violet/blue roses and carnations. The transgenic carnations are sold in various countries. The transgenic rose will be commercialized occur in Japan within a year2009.