Development of new cultivars for the flower business: From gene isolation to market

Hybridization breeding using wild and cultivated species has been utilized to create new floricultural cultivars. Genetic modification (GM) is a more recent technology, with the potential to create novel cultivars without the restriction of the natural gene pool imposed on traditional hybridization strategies. Roses, carnations and chrysanthemums lack a blue/violet flower colour because of their inability to synthesize the delphinidin-based anthocyanins, which most plants with blue/violet flowers produce. Flavonoid 3’,5’-hyroxylase is the key enzyme on the pathway to the synthesis of delphinidin-based anthocyanins. After countless trial-and-error experiments, introduction and expression of the flavonoid 3’,5’-hyroxylase gene in these important flower species has been achieved, resulting in significant colour change toward blue in flowers of transgenic plants. After clearing the complicated regulatory procedures for GM plants, the colour-modified carnations (Florigene ‘Moon’ series™) have been sold in North America, Japan, Europe and other countries since 1996. The colour-modified rose (Suntory Blue Rose ‘Applause’™) has been sold in Japan since 2009. The scientific and regulatory difficulties we have experienced during the development and commercialization of the GM flower cultivars will be discussed.