Target mutation breeding of flower color by taking advantage of ion-beam irradiation and genomic information

Tanaka, Atsushi

We launched a project to overcome the randomness of mutation and to develop logical and efficient mutation breeding by taking advantage of both ion-beam irradiation and genomic information. This research was supported by a five-year grant from the Research and Development Program for New Bio-industry Initiatives of the Bio-oriented Technology Research Advancement Institution (BRAIN). To achieve our purpose, we focused on flower-color mutations, because flavonoid biosynthesis is one of the most well-known molecular mechanisms in higher plants. We envisioned four ideal target plants for mutation breeding. These were glittering carnation, red creeping petunia, and blue-purple and crimson fragrant cyclamen. Several new factors that strongly affect flower color were identified from this project: (1) Non-acylation was found in a glittering carnation petal. (2) A loss-of-function mutation in GST (glutathione S-transferase) caused not only a decrease of pigmentation but also a change in flower color in carnation. (3) Carnation flower color was strongly affected by the function of AA5GT (acyl-glucose dependent anthocyanin 5-glucosyltransferase). (4) Delphinidins caused cyclamen flowers to turn red-purple. (5) A decrease in flavonol metabolism caused increased amounts of pigmentation in cyclamen flowers.