STABLE TRANSFORMATION OF GLADIOLUS USING SUSPENSION CELLS AND CALLUS

More than 100 transgenic Gladiolus plants were recovered after particl e bombardment of regenerable suspension cells and callus. For transfor mation, Gladiolus callus and suspension cells were co-bombarded with p hosphinothricin acetyltransferase-(PAT) and beta-glucuronidase (GUS)-e xpressing plasmids. Stably transformed calli were selected on medium c ontaining either phosphinothricin (PPT) or bialaphos followed by trans fer to a regeneration medium to recover transgenic plants. Stable tran sformation was confirmed by detection of the PAT gene by DNA gel blot analysis and by enzymatic assays to measure GUS activity. In general, particle bombardment of regenerable suspension cells rather than callu s resulted in the largest number of transformants. The rate of co-expr ession for GUS in PPT-resistant plants was high (approximate to 70%). Promoters that are typically more efficient in dicotyledonous plants w ere very active in Gladiolus, a monocotyledonous bulb plant. Establish ment of an efficient transformation protocol for Gladiolus will now al low the introduction of transgenes to confer resistance to the viral a nd fungal pathogens that decrease Gladiolus production.