Plant artificial chromosomes, uses thereof and methods of preparing plant artificial chromosomes

An isolated plant artificial chromosome comprising one or more repeat regions, wherein:

• one or more nucleic acid units is (are) repeated in a repeat region;
• repeats of a nucleic acid unit have common nucleic acid sequences;
• and
• the repeat region(s) contain substantially equivalent amounts of euchromatic and heterochromatic nucleic acid.

A method of identifying plant genes encoding particular traits, comprising:

• generating an artificial chromosome comprising euchromatic DNA from a first species of plant;
• introducing the artificial chromosome into a plant cell of a second species of plant;
• and
• detecting phenotypic changes in the plant cell comprising the artificial chromosome and/or a plant generated from the plant cell comprising the artificial chromosome.

A method for producing an acrocentric plant chromosome, comprising:

• introducing nucleic acid comprising a recombination site adjacent to nucleic acid encoding a selectable marker into a first plant cell;
• generating a first transgenic plant from the first plant cell;
• introducing nucleic acid comprising a promoter functional in a plant cell, a recombination site and a recombinase coding region in operative linkage into a second plant cell;
• generating a second transgenic plant from the second plant cell;
• crossing the first and second plants;
• obtaining plants resistant to an agent that selects for cells containing the nucleic acid encoding the selectable marker;
• and
• selecting a resistant plant that contains cells comprising an acrocentric plant chromosome.

A method of producing a plant artificial chromosome, comprising:

• introducing nucleic acid into a plant acrocentric chromosome in a cell, wherein the short arm of the acrocentric chromosome does not contain euchromatic DNA;
• culturing the cell through at least one cell division;
• and
• selecting a cell comprising an artificial chromosome that is predominantly heterochromatic.

A method for producing an artificial chromosome, comprising:

• introducing nucleic acid into a plant cell;
• and
• selecting a plant cell comprising an artificial chromosome that comprises one or more repeat regions
• wherein:
• one or more nucleic acid units is (are) repeated in a repeat region;
• repeats of a nucleic acid unit have common nucleic acid sequences;
• and
• the common nucleic acid sequences comprise sequences that represent euchromatic and heterochromatic nucleic acid.

An isolated plant artificial chromosome comprising one or more repeat regions, wherein:

• one or more nucleic acid units is (are) repeated in a repeat region;
• repeats of a nucleic acid unit have common nucleic acid sequences;
• and
• the common nucleic acid sequences comprise sequences that represent euchromatic and heterochromatic nucleic acid.

A method of producing a plant artificial chromosome, comprising:

• introducing nucleic acid into a plant chromosome in a cell, wherein the chromosome contains adjacent regions of rDNA and heterochromatic DNA;
• culturing the cell through at least one cell division;
• and
• selecting a cell comprising an artificial chromosome.

A vector, comprising:

• nucleic acid encoding a selectable marker that is not operably associated with any promoter, wherein the selectable marker permits growth of animal cells in the presence of an agent normally toxic to the animal cells;
• and wherein the agent is not toxic to plant cells;
• a recognition site for recombination;
• and
• a sequence of nucleotides that facilitates amplification of a region of a plant chromosome or targets the vector to an amplifiable region of a plant chromosome.

A vector, comprising:

• nucleic acid encoding a selectable marker that is not operably associated with any promoter, wherein the selectable marker permits growth of animal cells in the presence of an agent normally toxic to the animal cells;
• and wherein the agent is not toxic to plant cells;
• a recognition site for recombination;
• and
• nucleic acid encoding a protein operably linked to a plant promoter.

A vector, comprising:

• nucleic acid encoding a selectable marker that is not operably associated with any promoter, wherein the selectable marker permits growth of plant cells in the presence of an agent normally toxic to the plant cells;
• and wherein the agent is not toxic to animal cells;
• a recognition site for recombination;
• and
• nucleic acid encoding a protein operably linked to a plant promoter.

A method, comprising:

• introducing a vector into a cell, wherein:
• i) the vector comprises:
• a) nucleic acid encoding a selectable marker that is not operably associated with any promoter, wherein the selectable marker permits growth of animal cells in the presence of an agent normally toxic to the animal cells;
• and wherein the agent is not toxic to plant cells;
• b) a recognition site for recombination;
• and
• c) nucleic acid encoding a protein operably linked to an animal promoter;
• ii) the cell comprises:
• a platform plant artificial chromosome (PAC) that comprises a recombination site and an animal promoter that upon recombination is operably linked to the selectable marker that, in the vector, is not operably associated with a promoter;
• iii) introduction is effected under conditions whereby the vector recombines with the PAC to produce a plant platform PAC that contains the selectable marker operably linked to the promoter;
• and
• culturing the resulting cell under conditions, whereby the protein encoded by nucleic acid operably linked to an animal promoter is expressed.

A plant transformation vector, comprising:

• a recognition site for recombination;
• a sequence of nucleotides that facilitates amplification of a region of a plant chromosome or targets the vector to an amplifiable region of a plant chromosome;
• and
• one or more selectable markers that when expressed in a plant cell permit the selection of the cell;
• wherein the plant transformation vector is for Agrobacterium-mediated transformation of plants.