Agrobacterium-mediated genetic transformation in Gerbera hybrida

Agrobacterium-mediated genetic transformation protocol was developed for the commercially important ornamental Gerbera hybrida. Petiole, leaf and shoot tip expiants from 3 to 4 week old in vitro grown shoots of gerbera were co-cultured with Agrobacterium tumefaciens strain LBA4404. The strain harbours a binary vector containing neomycin phosphotransferase (nptII) and β-glucuronidase (uidA) genes. Callus formation and shoot regeneration were obtained on MS medium containing BAP, kinetin (1.0 mg/l each) and NAA (0.5 mg/l). Selection on the regeneration medium supplemented with 20 mg/l kanamycin allowed production of transgenic plants from 0.44% to 17.0% of the expiants. GUS activity was detected by histochemical staining. Transfer of uidA and nptII genes was analysed by PCR and Southern hybridization. Transformed shoots were multiplied on MS medium containing 0.25 mg/l BAP, rooted in half strength MS medium supplemented with 40 mg/l kanamycin and successfully transferred to soil. This protocol could be used to introduce horticulturally important genes that govern pigment biosynthesis in flowers.