An Efficient Transformation System in Chrysanthemum [Dendranthema×grandiflorum (Ramat.) Kitamura ] for Stable and Non-chimeric Expression of Foreign Genes.

Abstract

We succeeded in establishing a stable and efficient transformation system of chrysanthemum (cv. Shuho-no-chikara) which could eliminate both the appearance of the chimeric regenerants consisting of transgenic and non-transgenic tissues and that of the transgene inactivated regenerants. We compared two transformation systems, callus induction (CI) system and adventitious shoot induction (SI) system. The transformation frequency in CI system (4.4%) were higher than that in SI system (0.3%). All regenerated plantlets obtained by CI system express gus gene stably even after vegetative propagation. While a few regenerants obtained by SI system have gus gene and express gus gene in chimeric manner. Then we applied the CI system in other famous and commercial cultivars of chrysanthemum and obtained transformed plants with high transformation frequency in 15 among 21 cultivars. Regarding the stable gus gene expression in all regenerants, CI system should eliminate gene inactivation in regenerants and is beneficial for the production of genetically engineered chrysanthemum.