Genetic transformation of different chrysanthemum cultivars via somatic embryogenesis

In the present study, the effective transformation system of chrysanthemum through somatic embryogenesis was established. The effects of plant growth regulators and components of the nutrient medium were studied for the induction of somatic embryogenesis from leaf explants of two chrysanthemum cultivars. To improve the frequency of regeneration, explants were cultured on a liquid and solid MS medium sequentially. The cultivars were transformed using A. tumefaciens strain AGL0:pBin-mGFP5-ER carrying neomycin phosphotransferase gene (nptII) and gfp gene with a leader sequence for expression in endoplasmatic reticulum. The formation of somatic embryos was observed 10-16 days after transformation. Plants were efficiently regenerated from embryos during 4-8 weeks. In total, 60 plants were regenerated from 200 infected explants. PCR showed that 92.0% of the plants were transgenic. Expression of the gfp gene was detected in the embryogenic stage. This developed transformation system provides a base system for future experiments of genetic improvement of chrysanthemum. The investigation of the optimization of the plant growth medium for inducing embryogenesis from leaf explants and successful genetic transformation of two chrysanthemum cultivars is reported.