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.