REGENERATION OF FERTILE TRANSGENIC INDICA (GROUP-1) RICE PLANTS FOLLOWING MICROPROJECTILE TRANSFORMATION OF EMBRYOGENIC SUSPENSION-CULTURE CELLS

Regenerable embryogenic suspensions of elite Indica (group 1) rice var ieties IR24, IR64, IR72 and an advanced Indica rice breeding line IR57 311-95-2-3 were established within 6-8 weeks from 3-4 week old calli d erived from mature seeds. Transgenic rice plants were obtained by intr oducing a plasmid carrying genes encoding hygromycin phosphotransferas e (hph, conferring resistance to hygromycin B) and beta-glucuronidase (uidA), both driven by the CaMV 35S promoter, via particle bombardment of embryogenic suspensions. The effect of osmotic conditioning on tra nsformation was evaluated. Regenerated plants were resistant to hygrom ycin B and expressed the uidA (GUS) gene. The growth of mother plants (RO) was normal and seeds were produced. Southern blot analysis of R(0 ) and R(1) plants showed that hygromycin resistant plants contained in tact hph genes that were inherited in a Mendelian fashion. A protocol for a simple, efficient, repeatable, genotype- and environment-indepen dent Indica rice transformation system is described.