Patent ID: 7235711

Claim:
A method for obtaining a transplastomic plant comprising the steps of: a) introducing into a plant cell plastid a plastid transformation vector comprising two distinct selectable marker constructs, wherein the first selectable marker construct comprises a promoter functional in a plant cell plastid and a transcriptional termination region functional in a plant cell plastid operably linked to a first selectable marker (a non-lethal marker) that confers resistance to a non-lethal selective compound and the second selectable marker construct comprises a promoter functional in a plant cell plastid and a transcriptional termination region functional in a plant cell plastid operably linked to a second selectable marker (a lethal marker) that confers tolerance to a lethal compound, wherein the second selectable marker construct is flanked by nucleic acid sequences which are homologous to non-essential plastid targeting nucleic acid sequences, and the first selectable marker construct is flanked by nucleic acid sequences which are homologous to essential plastid targeting nucleic acid sequences; b) placing a plant cell comprising the recombinant nucleic acid molecule on a first culture medium comprising a plastid non-lethal compound to which the first selectable marker confers resistance for either 1) a period of about 2 weeks or 2) or until shoots appear on a callus formed from the plant cell; and c) placing the plant cell on a second culture medium comprising a plastid lethal compound to which the second selectable marker confers resistance for a period of time sufficient to permit the plant cell to be homoplasmic for the lethal marker; and d) obtaining a transplastomic plant by regenerating the transplastomic plant from the plant cell, wherein the transplastomie plant does not comprise the first selectable marker.