Genetic transformation mediated by Agrobacterium tumefaciens of florists' chrysanthemum (Dendranthema Xgrandiflorum) cultivar 'Peach Margaret'

A genetic transformation method using Agrobacterium tumefaciens strain LBA4404 and based on the neomycin phosphotransferase II (nptII) selectable marker gene is described for a cultivar of florists' chrysanthemum, Dendranthema Xgrandiflorum 'Peach Margaret.' We used the flavonoid regulatory cDNA, Leaf color (Lc) from the monocot Zea mays (maize), under control of the cauliflower mosaic virus 35S promoter, to test if it would serve as a visible, nondestructive pigmentation reporter of transformation in chrysanthemum and to see if we could modify floral and leaf pigmentation. Stable integration of the maize Lc cDNA in 'Peach Margaret' was confirmed by Southern DNA analysis. However, no Lc RNA transcripts were detected and no increase in pigmentation was observed in the transformants. In contrast, activity of the nptII transgene in the transformants was confirmed by production of roots in the presence of 20 mg/l kanamycin and challenging leaf explants to regenerate shoots in the presence of 25 mg/l kanamycin. This is the first reported method based on Agrobacterium tumefaciens for genetic transformation of cultivar 'Peach Margaret'.