Abstract: Methods and compositions using populations of randomized modified FRT recombination sites to identify, isolate and/or characterize modified FRT recombination sites are provided. Kits comprising the library populations of FRT sites are also provided, as are methods to make a library of modified FRT recombination sites. The recombinogenic modified FRT recombination sites can be employed in a variety of methods for targeted recombination of polynucleotides of interest.

Abstract: Methods and compositions using populations of randomized mod fie FRT recombination sites to identify, isolate and/or characterize modified FRT recombination sites are provided. Kits comprising the library populations of FRT sites are also provided, as are methods to make a library of modified FRT recombination sites. The recombinogenic modified FRT recombination sites can be employed in a variety of methods for targeted recombination of polynucleotides of interest.

Abstract: Methods of making a targeted modification in a male fertility gene in the genome of a plant are disclosed. The methods involve contacting a plant cell with an engineered double-strand-break-inducing agent capable of inducing a double-strand break in a target sequence in the male fertility gene and identifying a cell comprising an alteration in the target sequence. Also disclosed are plants, plant cells, plant parts, and seeds comprising a male fertility gene with an alteration in a male fertility gene. Nucleic acid molecules comprising male fertility genes with at least one targeted modification therein, optimized nucleic acid molecules encoding endonucleases that are engineered double-strand-break-inducing agents and expression cassettes, host cells, and plants comprising one or more of the nucleic acid molecules are further disclosed.

Abstract: Methods for producing homozygous plants, seeds, and plant cells are provided. The methods comprise transforming a somatic cell of a maize haploid embryo with a polynucleotide of interest and treating the transformed cell with a chromosome doubling agent. One or more growth stimulation proteins, such as, for example, RepA or Lec1, may also be provided.

Abstract: Methods and compositions using populations of randomized modified FRT recombination sites to identify, isolate and/or characterize modified FRT recombination sites are provided. The recombinogenic modified FRT recombination sites can be employed in a variety of methods for targeted recombination of polynucleotides of interest, including methods to recombine polynucleotides, assess promoter activity, directly select transformed organisms, minimize or eliminate expression resulting from random integration into the genome of an organism, such as a plant, remove polynucleotides of interest, combine multiple transfer cassettes, invert or excise a polynucleotide, and identify and/or characterize transcriptional regulating regions are also provided.

Abstract: Methods and compositions using populations of randomized modified FRT recombination sites to identify, isolate and/or characterize modified FRT recombination sites are provided. Kits comprising the library populations of FRT sites are also provided, as are methods to make a library of modified FRT recombination sites. The recombinogenic modified FRT recombination sites can be employed in a variety of methods for targeted recombination of polynucleotides of interest.

Abstract: Methods for producing homozygous plants, seeds, and plant cells are provided. Methods of forming haploid tissue and then doubling the chromosomes to form doubled haploid cells are provided. Also provided are methods of transformation.

Abstract: A method for the production of transgenic plants is provided in which a vector carrying a gene encoding the green fluorescent protein is introduced into cells, the cells are screened for the protein and transformed cells are selected and regenerated. The cellular toxicity of the green fluorescent protein is circumvented by regulating expression of the gene encoding the protein or directing the protein to a subcellular compartment where it is not toxic to the cell. DNA constructs are provided for cell transformation in which the expression of a gene encoding the green fluorescent protein is placed under the control of an inducible promoter. In addition, DNA constructs are provided in which a nucleotide sequence encoding the green fluorescent protein is operably linked to a signal sequence which directs the expressed protein to a subcellular compartment where the protein is not toxic to the cell.

Abstract: Bacteria of the species Agrobacterium are applied to particles which are used in a typical particle gun in a manner which retains their viability after the dry-down process involved in microparticle bombardment. When plant materials are bombarded with particles coated with the bacteria, high rates of stable transformation are achieved.

Abstract: Plant cells in tissue culture are more efficiently transformed in a method which involves treatment with a cytokinin followed by incubation for a period sufficient to permit undifferentiated cells in cotyledonary node tissue to differentiate into meristematic cells and to permit the cells to enter the phases between the G1 and division phases of development.