Agrobacterium fumefaciens - mediated Transformation of Rice Using Coleoptile and Mature Seed-derived Callus

Morphologically normal, fertile transgenic rice plants (Oryza sativa L cv Taipei 309) were obtained using Agrobacterium tumefaciens strain LEA4404 harbouring the plasmid pTOK233. Two transgenic systems were developed. The first involved callus derived from mature seeds (scutellum) and, the second, used callus derived from 4-d-old coleoptiles. This is the first time that a coleoptile-based system has been used for producing transgenic rice plants. In the development of coleoptile based system, we have evaluated the effect of the length of callus induction period of the coleoptiles on transformation efficiency. The proportion of GUS positive plants was 23% in coleoptile experiment while in mature seed experiments it was 21%. Southern analyses were done to confirm the presence of the transgene. It was found that one to three copies of the transgene integrated in the transgenic plants.