PLASTID TRANSFORMATION IN ARABIDOPSIS-THALIANA

Plastid transformation is reported in Arabidopsis thaliana following b iolistic delivery of transforming DNA into leaf cells. Transforming pl asmid pGS31A carries a spectinomycin resistance (aadA) gene flanked by plastid DNA sequences to target its insertion between trnV and the rp s12/7 operon. Integration of aadA by two homologous recombination even ts via the flanking ptDNA sequences and selective amplification of the transplastomes on spectinomycin medium yielded resistant cell lines a nd regenerated plants in which the plastid genome copies have been uni formly altered. The efficiency of plastid transformation was low: 2 in 201 bombarded leaf samples. None of the 98 plants regenerated from th e two lines were fertile.