(283) Petal Color Changes in Carnation Plants Transformed with an Antisense DFR and a CHI Gene

To produce transgenic carnation plants expressing modified flower colors, cultivars of red-flowering carnation (`Desio' and `Garnet') were transformed with a antisense DFR gene encoding dihydroflavonol-4-reductase, and yellow-flowering carnations (`Pallas' and `Keumbyul') were introduced with a CHI gene encoding chalcone synthease isomerase. Explants of leaves, stems, and shoot tips were inoculated with Agrobacterium and grown overnight in induction broth supplemented with 0.2 m m acetosyringone. The cocultures of carnation explants were maintained in the light at 24 °C on one-half strength MS medium solidified with 0.3% Gelite and supplemented with 1.0 mg·L -1 BA for 10 days, and then were transferred to a selection medium containing 250 mg·L -1 cefotaxime/carbenicillin, 500 mg·L -1 kanamycin. They were subcultured every 2 weeks for over six times and regenerated. In `Garnet' and `Desio' carnation cultivars, a total of 146 plants was transformed with anti-sense DFR gene in pGA748/LBA4404. In yellow flowering cultivars `Pallas' and `Keumbyul', transformed with CHI gene in pGA748/LBA4404, 20 putative transformants obtained. The introduction of the transgenes were confirmed through PCR and flower color changes. Rates of phenotypic expression of the transgene, antisense DFR gene, vary among the transformants such as lighter pigmentation or chimeric discoloration, more prominently in outer petals of the flowers. Transgenic plants of chi gene bloomed flowers of lighter yellow petals in general. The most prominent phenotypic changes were discoloration of red strips on petals, which are typical characteristics of the cultivars.