AGROBACTERIUM-MEDIATED TRANSFORMATION OF RICE (ORYZA-SATIVA-L)

We have transformed embryo-derived cultures of two rice cultivars using several different Agrobacterium-mediated gene transfer systems. Mature embryos of cv. Nipponbare inoculated with the wide host range (WHR) supervirulent strain A281(pTiBo542) formed tumorigenic callus tissue that grew on hormone-free medium. The transformed status of this tissue was confirmed by DNA hybridization analysis that showed transferred DNA (T- DNA) present in the rice genome. Embryos of another variety, cv. Fujisaka 5, gave a hypersensitive response when inoculated with strain A281 but exhibited extensive root proliferation following inoculation with the limited host range (LHR) strain A856. These roots grew on hormone-free medium and produced octopine. Fujisaka 5 embryos subsequently inoculated with a disarmed WHR strain conferring kanamy- cin resistance and [β-D-glucuronidase (GUS) activity produced callus that grew on selective levels of kanamycin and this tissue fluoresced upon incubation with GUS substrate. GUS expression in the rice tissues was confirmed by Western blotting. We conclude that T-DNA has been transferred to, integrated and then expressed in rice cells. © 1990 Nature Publishing Group.