STABLE GENETIC-TRANSFORMATION OF ARABIDOPSIS-THALIANA BY AGROBACTERIUM INOCULATION IN PLANTA

Stable genetic transformation of Arabidopsis thaliana was achieved by simple in planta inoculation of Agrobacterium tumefaciens strain LBA44 04 harboring a binary vector pBI121. The transformation procedure, whi ch we call in planta transformation, involves severing of apical shoot s at their bases, inoculation with Agrobacterium at the severed sites, and in planta generation of shoots from the severed sites. On average , 5.5% of the newly formed shoots produced transformed progenies. Thes e progenies (T-2 generation) contained T-DNA in the genome as examined by assaying the T-DNA encoded beta-glucuronidase and kanamycin resist ance and by genomic Southern blot analysis, the copy number of the T-D NAs in the Arabidopsis genome being single (33%) or multiple. The gene tic behavior of the transformants examined at the T-3 and T-4 generati ons or with the F-2 progenies of the outcrosses between transformants and wild-type plants showed that most of the inserted T-DNA are inheri ted in a Mendelian fashion. This procedure provides a new approach for simple and efficient transformation of A. thaliana, obviating the nee d for plant regeneration from tissue explants in vitro.