Preliminary report on Agrobacterium-mediated genetic transformation of Begonia Rex and Saintpaulia spp.

摘要

In order to understand the shoot-forming process of leaf epidermal tissue of Saintpaulia and Begonia Rex, we attempted to create a cytokinin over-producing transformant. An Agrobacterium-mediated transformation system was established for these two species. Leaf explants were excised from in vitro cultured Begonia Rex and Saintpaulia spp. plantlets. A. tumefaciens with a plasmid harboring GUS and hpt genes was used as marker. For Saintpaulia spp., leaf explants of two cultivars (‘Heavens A-calling’ and ‘Kris’) were cultured on nine combinations of concentrations of NAA and BAP. The former cultivar produced more shoots than the latter and the optimum plant growth regulator concentration was different for these two cultivars. The optimum concentration of hygromycin B for Begonia and Saintpaulia was 20 μg/ml and 30 μg/ml, respectively, if explants were pre-cultured for two to three weeks. GUS gene expressing shoots were obtained most abundantly when explants were pre-cultured on medium supplemented with NAA and BAP for 15 to 21 days before co-culture with Agrobacterium. Using this protocol, it was possible to obtain transformants efficiently for further study.