Abstract: The invention provides processes for generating transgenic plants or plant cells transformed on their plastome, comprising introducing into plant plastids a first and a second DNA molecule, wherein the first DNA molecule contains a first region homologous to a region of the plastome for directing plastome integration and a first sequence of interest, and the second DNA molecule contains a second region homologous to a region of the plastome and a second sequence of interest, whereby a sequence segment of the first sequence of interest is homologous to a sequence segment of the second sequence of interest, and selecting transformants having an integration sequence stably integrated in the plastome, whereby the integration sequence contains at least a portion of the first and second sequences of interest as a continuous sequence. The invention further provides plant cells, plants, and seeds of plants produced by such processes.

Abstract: 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) a nucleotide sequence conferring replication of said DNA in a plant cell, (ii) at least one sequence of interest, (iii) 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 (iv) a selection marker outside of said sequences flanking said sequence(s) of interest; (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.

Abstract: A process for producing multicellular plants, plant organs or plant tissues transformed on their plastome by the following steps is provided: (a) altering or disrupting the function of a gene in a plastid genome for producing a selectable or recognizable phenotype; (b) separating or selecting plants or cells having plastids expressing said phenotype; (c) transforming said plastid genome of said separated or selected plant, plant organ or plant tissue with at least one transformation vector having a restoring sequence capable of restoring said function; and (d) separating or selecting said transformed plant, plant organ or plant tissue having plastids expressing said restored function.

Abstract: This invention provides cyanobacteria as an alternative source of ahas and pds genes for plant transformations and for selectable markers. In particular, it provides for cyanobacteria, for example, Synechocystis, as a source of genes encoding herbicide insensitive proteins, and elements of genes for control of expression in plastids. Nucleic acid fragments, both the acetolactate synthase (ahas) large subunit and the ahas small subunit, were found to provide herbicide resistance. Also, the present invention provides novel Synechocystis mutant phytoene desaturase (PDS) gene conferring resistance to 4?-fluoro-6[(alpha,alpha,alpha,-trifluoro-m-tolyl)oxy]-picolinamide, a bleaching herbicide. The present invention provides improvements to method involving cyanobacteria for the screening of compounds, including a new high-through-put protocol that is a rapid and cost effective way to identify target site genes.

Abstract: 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) a nucleotide sequence conferring replication of said DNA in a plant cell, (ii) at least one sequence of interest, (iii) 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 (iv) a selection marker outside of said sequences flanking said sequence(s) of interest; (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.

Abstract: This invention discloses a novel process and vector therefore for producing a multicellular plant or plant cells having stably transformed plastids. This process comprises transforming plastids or plant cells via homologous recombination with a DNA molecule enabling DNA modification, whereby said DNA molecule comprises a fragment of a gene requiring for expression a sequence element of the host plastid. The invention also includes the use of novel selection inhibitors for plastic transformation and the possibility of performing multiple rounds of transformation without accumulation of resistance genes.

Abstract: A process for producing multicellular plants, plant organs or plant tissues transformed on their plastome by the following steps is provided: (a) altering or disrupting the function of a gene in a plastid genome for producing a selectable or recognizable phenotype; (b) separating or selecting plants or cells having plastids expressing said phenotype; (c) transforming said plastid genome of said separated or selected plant, plant organ or plant tissue with at least one transformation vector having a restoring sequence capable of restoring said function; and (d) separating or selecting said transformed plant, plant organ or plant tissue having plastids expressing said restored function.