TRANSFORMATION OF ANTISENSE DIHYDROFLAVONAL 4-REDUCTASE (DFR) INTO SACRED LOTUS 'BUNTHARIK' USING AGROBACTERIUM-MEDIATED GENE TRANSFER

Transformation of antisense dihydroflavonal 4-reductase (DFR) into ‘Buntharik’ sacred lotus (Nelumbo nucifera Gaertn.) using Agrobacterium-mediated gene transfer was experimented. The A. tumefaciens strain EHA105 harbored two binary vectors. The pCAMBIA2301anti-DFR plasmid contained neomycin phosphotransferase (NPTII) as a selectable marker gene, the antisense DFR as an inserted gene and the β-glucuronidas gene (GUS) as a reportor gene. The pBI121anti-DFR plasmid contained NPTII gene and the antisense DFR. Two-months-old calli regenerated from apical buds were used as plant materials. The plant materials were soaked in the Agrobacterium suspension for 10 or 30 min. The calli were co-cultivated for two days in the darkness. Treated calli were selected on solid MS medium containing 50 mg L-1 kanamycin and 250 mg L-1 cefotaxime. The calli were transferred to the same medium every two weeks for eight weeks. The survived calli regenerated shoots on MS medium containing a combination of 0.54 µM NAA and 4.44 µM BA. Both plasmids gave the best callus growth, maximum callus size and the survival percentage when soaked for 10 min. GUS bioassay was used to verify the presence of GUS gene in petioles and leaves of transgenic plants. It was found that petioles and leaves of transformants which were transformed with pCAMBIA2301anti-DFR by soaking for 30 min showed the highest percentage of blue spots on explants. Of all 14 PCR positive clones, 5 clones showed GUS gene, 11 clones contained NPTII gene and 6 clones had DFR gene.