TRANSGENIC RICE - CHARACTERIZATION OF PROTOPLAST-DERIVED PLANTS AND THEIR SEED PROGENY

Thirty eight green and 2 albino plants were regenerated from 400 kanamycin-resistant colonies derived from protoplasts isolated from cell suspensions of Oryza sativa variety Taipei 309 and electroporated with pCaMVNEO carrying the neomycin phosphotransferase II (nptII) gene. Twenty of the green transgenic R0 plants were transferred to the glasshouse, where 3 flowered after 7 months. Of 15 plants analysed by DNA hybridization, all carried the nptII gene, but only 2 of 11 plants assayed for NPTII activity expressed the nptII gene. One transgenic R0 plant produced 59 seeds following self-pollination. The seeds, when germinated on medium containing kanamycin sulphate, gave 16 green transgenic R1 plants. Five transgenic R1 plants flowered and set seed, 7 flowered but failed to produce seeds, while 4 did not produce panicles. Transgenic R0 and R1 plants were shorter, required longer to flower, and had reduced pollen viability compared to non-transformed R1 protoplast-derived plants. The nptII gene was present in all 16 transgenic R1 plants, but NPTII activity was detected in only 8 of these plants.