XVI International Botanical Congess

Robinia pseudoacacia is a leguminous tree species, and it has been planted in the world. We established a simple and reliable procedure for the Agrobacterium-mediated transformation of R. pseudoacacia. Genetically transformed plants were regenerated after co-cultivation of leaf and cotyledon disks with A. tumefaciens strain GV3101 that harbored binary vector included genes for ß-glucuronidase (GUS) and hygromycin phosphotransferase (HPT). Successful transformation was confirmed by the ability of leaf or cotyledon disks to produce calli in the presence of hygromycin, by histochemical assay of GUS activity in plant tissues, and by detection of the HPT gene in the genome. With this transformation system, about 2 months were required for regeneration of the transgenic plants from leaf and cotyledon disks. The frequency of transformation was approximately 6%. We also introduced the rice homeobox gene OSH1, and induced morphological changes in R. pseudoacacia plants by the overexpression of the OSH1 gene.