Patent ID: 7795497

Claim:
A method of selecting for a transformed plant cell of a species that is naturally inhibited by betaine aldehyde, wherein said method does not require selection for successful transformants by detection of antibiotic resistance, said method comprising introducing into a plastid genome of a starting plant cell of said species an integration and expression cassette which comprises, as operably linked components, a 5′ end of a plastid DNA spacer sequence, a 5′ untranslated region (UTR) having a ribosome binding site, a DNA sequence encoding a plant betaine aldehyde dehydrogenase capable of detoxifying a betaine aldehyde in said transformed plant cell, a 3′ regulatory region functional in said plastid, and a 3′ end of a plastid DNA spacer sequence, wherein said method further comprises culturing said plant cell in a plant growth medium comprising said betaine aldehyde, and selecting said transformed plant cell comprising said plastid genome in which the DNA sequence encoding a detoxifying enzyme is expressed and hence is capable of growth in the presence of said betaine aldehyde.