Transformation of chrysanthemum leaf explants using Agrobacterium tumefaciens
This chapter uses Agrobacterium tumefaciens, a soil inhabiting, pathogenic bacterium occurring naturally in many areas of the world, as the agent/vector or shuttle that transfers genes between the two species. In recent years there has been increased interest in the transformation of ornamental plants, and chrysanthemum. Most of the interest in genetically transforming chrysanthemum thus far has been in the areas of creating new flower colors and conferring resistance to tomato spotted wilt virus. Successful transformation of cells within the leaf explants of the corresponding pairs of both 'Goldmine' and 'Iridon' is indicated by the production of copious amounts of yellow-green callus that is typically not produced during shoot formation. Most shoots formed from explants treated with bacteria should be bleached, but putatively transformed shoots will remain dark green. Some of these will be escapes and all green shoots should be excised and recultured to medium containing cefotaxime and kanamycin for an additional three weeks.