Process of generating transplastomic plants or plant cells devoid of a selection marker

1. A process of generating transgenic plants or plant cells transformed on their plastome and being devoid of a selection marker, comprising the following steps:

(a) transforming plastids of a plant or plant cell with a DNA comprising:

(i) at least one sequence of interest,

(ii) sequences flanking said at least one sequence of interest necessary for stable integration of said at least one sequence of interest into the plastid genome, and

(iii) a selection marker functional in a plastid and located outside of said sequences flanking said sequence(s) of interest, wherein said selection marker is not flanked by plastid DNA sequences;

(b) allowing integration of said at least one sequence of interest into the plastome in the presence of selective pressure;

(c) allowing loss of said selection marker sequence by releasing selective pressure; and

(d) recovering cells and/or plants being genetically transformed on their plastomes and being devoid of said selection marker.

2. The process of claim 1 , wherein said sequence of interest comprises a sequence which allows visual identification of cells containing transformed plastomes.

3. The process of claim 1 , wherein the plant or plant cells to be transformed has a mutation in the plastome which causes an easily distinguishable phenotype, and whereby said process restores said easily distinguishable mutant phenotype, thereby allowing identification of transformed cells.

4. The process of claim 1 , wherein, in a previous step, a photosynthesis-related gene is rendered dysfunctional or is eliminated.

5. The process of claim 4 , wherein said photosynthesis related gene is selected from the group consisting of rpoA, petA, ycf3, ycf9, and rpoB.

6. The process of claim 4 , wherein said DNA contains said photosynthesis-related gene functional for allowing positive selection of said transformation.

7. The process of claim 1 , wherein the selection marker encodes bacterial aminoglycoside phosphotransferase A-6.

8. The process of claim 1 , wherein a nucleotide sequence of the plastome is deleted.

9. The process of claim 8 , wherein said flanking sequences (ii) are homologous to plastome sequences that flank said nucleotide sequence of the plastome to be deleted.

10. The process of claim 1 , wherein a point mutation is created in the plastome.

11. The process of claim 1 wherein steps (c) and/or (d) comprise allowing segregation of leaf sectors each containing a particular type of plastome.

12. A transformation vector comprising a DNA comprising:

(a) at least one sequence of interest,

(b) sequences flanking said at least one sequence of interest necessary for stable integration of said at least one sequence of interest into the plastid genome, and

(c) a selection marker functional in a plastid and located outside of said sequences flanking said sequence(s) of interest, wherein said selection marker is not flanked by plastid DNA sequences.

13. The process of claim 1 , wherein the DNA further comprises a nucleotide sequence conferring replication of said DNA in a plant cell.

14. The process of claim 1 , wherein the DNA further comprises a nucleotide sequence conferring non-autonomous replication of said DNA in a plant cell.