Methods and compositions for the introduction and regulated expression of genes in plants

A method for transforming a plastid of a plant cell with a polynucleotide of interest, said method comprising:

• a) introducing into a plant cell a heterologous polynucleotide encoding a cell proliferation factor;
• b) expressing said heterologous polynucleotide encoding said cell proliferation factor;
• and
• c) introducing into a plastid of said plant cell a vector comprising said polynucleotide of interest, wherein the heterologous polynucleotide encoding said cell proliferation factor is expressed prior to, during, or following the introduction into said plastid of said vector comprising said polynucleotide of interest.

A method for introducing a polynucleotide of interest into a mature embryo explant of a mature seed, said method comprising:

• a) dissecting a mature embryo from a mature seed;
• b) making slices of said mature embryo to prepare said mature embryo explant, wherein said mature embryo explant comprises at least one of the tissues selected from the group consisting of leaf primordia, mesocotyl, shoot apical meristem, and root primordia;
• and
• c) introducing into said mature embryo explant:
• i) a heterologous polynucleotide encoding a cell proliferation factor and expressing said heterologous polynucleotide encoding said cell proliferation factor;
• and
• ii) a polynucleotide of interest.

An isolated polypeptide comprising an amino acid sequence selected from the group consisting of:

• a) the amino acid sequence set forth in SEQ ID NO 2, 8, or 18;
• and
• b) an amino acid sequence having at least 75% sequence identity to the sequence set forth in SEQ ID NO:
• 2, wherein said polypeptide has BBM activity;
• c) an amino acid sequence having at least 75% sequence identity to the sequence set forth in SEQ ID NO:
• 4, wherein said amino acid sequence has amino acid residues valine, tyrosine, and leucine at the positions corresponding to positions 311, 312, and 313, respectively of SEQ ID NO:
• 4, wherein said polypeptide has BBM activity;
• d) an amino acid sequence having at least 75% sequence identity to the sequence set forth in SEQ ID NO;
• 8, wherein said amino acid sequence has amino acid residues methionine, alanine, and serine at the positions corresponding to positions 1, 2, and 3, respectively, of SEQ ID NO:
• 8, wherein said polypeptide has BBM activity;
• and
• e) an amino acid sequence having at least 75% sequence identity to the sequence set forth in SEQ ID NO:
• 18, wherein said amino acid sequence has amino acid residues valine, tyrosine, and leucine at the positions corresponding to positions 337, 338, and 339, respectively, of SEQ ID NO:
• 18, wherein said polypeptide has BBM activity.

An isolated polynucleotide comprising a nucleotide sequence selected from the group consisting of:

• a) a nucleotide sequence comprising the sequence set forth in SEQ ID NO:
• 1, 3, 7, or 17;
• b) a nucleotide sequence having at least 75% sequence identity to the sequence set forth in SEQ ID NO:
• 1, wherein said nucleotide sequence encodes a polypeptide having BBM activity;
• c) a nucleotide sequence encoding the amino acid sequence set forth in SEQ ID NO:
• 2, 4, 8, or 18;
• and
• d) a nucleotide sequence encoding a polypeptide having an amino acid sequence having at least 75% sequence identity to the amino acid sequence set forth in SEQ ID NO:
• 2, wherein said polypeptide has BBM activity;
• e) a nucleotide sequence encoding a poly-peptide having an amino acid sequence having at least 75% sequence identity to the sequence set forth in SEQ ID NO:
• 4, wherein said amino acid sequence has amino acid residues valine, tyrosine, and leucine at the positions corresponding to positions 311, 312, and 313, respectively of SEQ ID NO:
• 4, wherein said polypeptide has BBM activity;
• f) a nucleotide sequence encoding a polypeptide having an amino acid sequence having at least 75% sequence identity to the sequence set forth in SEQ ID NO 8, wherein said amino acid sequence has amino acid residues methionine, alanine, and serine at, the positions corresponding to positions 1, 2, and 3, respectively, of SEQ ID NO:
• 8, wherein said polypeptide has BBM activity;
• and
• g) a nucleotide sequence encoding a polypeptide having an amino acid sequence having at least 75% sequence identity to the sequence set forth in SEQ ID NO:
• 18, wherein said amino acid sequence has amino acid residues valine, tyrosine, and leucine at the positions corresponding to positions 337, 338, and 339, respectively, of SEQ ID NO:
• 18, wherein said polypeptide has BBM activity;
• h) the complement of any one of the nucleotide sequences of a), b), c), d), e), f), or g).

A plant comprising a heterologous polynucleotide operably linked to a promoter that drives expression in the plant, wherein said polynucleotide is selected from the group consisting of:

• a) a polynucleotide comprising the nucleotide sequence set forth in SEQ ID NO:
• 1, 3, 5, 7, 17, or 27;
• or a complement thereof;
• b) a polynucleotide comprising a nucleotide sequence having at least 75% sequence identity to the sequence set forth in SEQ ID NO:
• 1, 3, 5, 17, or 27;
• wherein said nucleotide sequence encodes a polypeptide having BBM activity;
• c) a polynucleotide encoding the amino acid sequence set forth in SEQ ID NO:
• 2, 4, 6, 8, 18, or 28;
• d) a polynucleotide encoding an amino acid sequence having at least 75% sequence identity to the sequence set forth in SEQ ID NO;
• 8, wherein said amino acid sequence has amino acid residues methionine, alanine, and serine at the positions corresponding to positions 1, 2, and 3, respectively, of SEQ ID NO:
• 8, wherein said polynucleotide encodes a polypeptide having BBM activity;
• and
• e) a polynucleotide encoding an amino acid sequence having at least 75% sequence identity to the amino acid sequence set forth in SEQ ID NO:
• 2, 4, 6, 18, or 28;
• wherein said polynucleotide encodes a polypeptide having BBM activity.

A method of increasing the activity of a polypeptide in a plant comprising providing to said plant a polypeptide selected from the group consisting of:

• a) the polypeptide comprising the amino acid sequence of SEQ ID NO:
• 2, 4, 6, 8, 18, or 28;
• b) the polypeptide having at least 75% sequence identity to SEQ ID NO:
• 2, 4, 6, 18, or 28, wherein said polypeptide has BBM activity;
• and
• c) the polypeptide having an amino acid sequence having at least 75% sequence identity to the sequence set forth in SEQ ID NO;
• 8, wherein said amino acid sequence has amino acid residues methionine, alanine, and serine at the positions corresponding to positions 1, 2, and 3, respectively, of SEQ ID NO:
• 8, wherein said polypeptide has BBM activity;
• and
• wherein increasing the activity of said polypeptide produces a phenotype in the plant selected from the group consisting of:
• a) produces asexually derived embryos in the plant;
• b) modifies the regenerative capacity of the plant;
• c) increases the transformation efficiency in the plant;
• d) increases or maintains the yield in the plant under abiotic stress;
• and
• e) induces embryogenesis.

A method of transforming a plant cell comprising:

• (a) transforming a plant cell with a polynucleotide of interest and a heterologous polynucleotide comprising a first nucleotide sequence selected from the group consisting of:
• a) a nucleotide sequence comprising SEQ ID NO:
• 1, 3, 5, 7, 17, or 27;
• b) a nucleotide sequence encoding the amino acid sequence of SEQ ID NO:
• 2, 4, 6, 8, 18, or 28;
• c) a nucleotide sequence having at least 75% sequence identity to SEQ ID NO:
• 1, 3, 5, 17, or 27, wherein said nucleotide sequence encodes a polypeptide having BBM activity;
• d) a nucleotide sequence encoding an amino acid sequence having at least 75% sequence identity to SEQ ID NO:
• 2, 4, 6, 18, or 28, wherein said nucleotide sequence encodes a polypeptide having BBM activity;
• and
• e) a nucleotide sequence encoding an amino acid sequence having at least 75% sequence identity to the sequence set forth in SEQ ID NO;
• 8, wherein said amino acid sequence has amino acid residues methionine, alanine, and serine at the positions corresponding to positions 1, 2, and 3, respectively, of SEQ ID NO:
• 8, wherein said nucleotide sequence encodes a polypeptide having BBM activity.