Transformation of Antirrhinum majus using Agrobacterium rhizogenes

Hairy roots were produced following the co-cultivation of Agrobacteriumrhizogenes cells with hypocotyls of five varieties of Antirrhinummajus. The use of a strain containing a binary plasmid withT-DNA bearing the ß-glucuronidase reporter gene resultedin the co-transformation of some root clones. Regeneration ofshoots from hairy roots occurred only with variety Golden Monarch.Regenerated plants, some of which were GUS-positive, exhibitedthe abnormal morphology common among hairy root regenerants;they were dwarfed, had an altered leaf shape, a poor root systemand were very delayed in their flowering. Attempts to allowsegregation of the two introduced T-DNAs during crossing ofprimary co-transformants with wild-type plants were not successfulsince all GUS-positive progeny possessed the abnormal morphology.However, ‘semi-dwarf’ plants with morphology muchmore similar to wild-type were produced by the vegetative propagationof selected side-shoots from the transformants. Key words: Antirrhinum, Agrobacterium rhizogenes, transformation, hairy roots