Genetic transformation of the C₄ plant, Flaveria bidentis

Summary An efficient and rapid transformation system for the dicotyledonous C 4 plant, Flaveria bidentis has been developed. The method involves Agrobacterium tumefaciens infection of explants followed by regeneration of shoots from kanamycin‐resistant callus. Shoots first appear on callus 3–4 weeks after Agrobacterium infection, with plants in soil after another 12–15 weeks. Transformation has been verified by measuring the activity of the gusA and npt ‐II transgenes and by genomic Southern blots to show the stable integration of T‐DNA. Most regenerated plants show normal morphology, are self‐fertile and transgenes show expected Mendelian segregations in the next generation. This system allows one to test a number of gene constructions rapidly and should accelerate progress in studies of the cell‐specific expression of genes coding for C 4 enzymes and the mechanisms regulating the activities of C 4 enzymes.