Methods and compositions for rapid plant transformation

A method for producing a transgenic Poaceae plant, comprising:

• (a) transforming a cell of a Poaceae explant with an expression construct comprising a heterologous gene of interest and
• (i) a nucleotide sequence encoding a WUS/WOX homeobox polypeptide and
• (ii) a nucleotide sequence encoding a Babyboom (BBM) polypeptide or an Ovule Development Protein 2 (ODP2) polypeptide;
• (b) allowing expression of the expression construct of (a) in each transformed cell for about 0 to about 7 days or for about 0 to about 14 days after initiation of transforming the cell, wherein a somatic embryo is formed within about 0 to about 7 days or within about 0 to about 14 days after initiation of transforming the cell, wherein the expression occurs in the absence of exogenous cytokinin or in the presence of exogenous cytokinin at a final concentration of 0.1 mg/L or less;
• and
• (c) germinating the somatic embryo to form the transgenic Poaceae plant;
• wherein the WUS/WOX homeobox polypeptide comprises an amino acid sequence comprising at least 95% sequence identity to any of SEQ ID NO:
• 4, 6, 8, 10, 12, 14, or 16;
• or the WUS/WOX homeobox polypeptide is encoded by a nucleotide sequence comprising at least 95% sequence identity to any of SEQ ID NO:
• 3, 5, 7, 9, 11, 13, or 15;
• and
• wherein the polypeptide comprising the BBM polypeptide or the ODP2 polypeptide comprises an amino acid sequence comprising at least 95% sequence identity to any of SEQ ID NO:
• 18, 20, 63, 65, or 67;
• or the polypeptide comprising the BBM polypeptide or the ODP2 polypeptide is encoded by a nucleotide sequence comprising at least 95% sequence identity to any of SEQ ID NO:
• 17, 19, 21, 62, 64, 66, or 68.

A method for producing a transgenic Poaceae plant comprising:

• (a) transforming a cell of a Poaceae explant with an expression construct comprising a heterologous gene of interest and
• (i) a nucleotide sequence encoding a WUS/WOX homeobox polypeptide and
• (ii) a nucleotide sequence encoding a Babyboom (BBM) polypeptide or an Ovule Development Protein 2 (ODP2) polypeptide;
• (b) allowing expression of the expression construct of (a) in each transformed cell for about 0 to about 7 days or for about 0 to about 14 days after initiation of transforming the cell, wherein a somatic embryo is formed within about 0 to about 7 days or within about 0 to about 14 days after initiation of transforming the cell, wherein the expression occurs in the absence of exogenous cytokinin or in the presence of exogenous cytokinin at a final concentration of 0.1 mg/L or less;
• and
• (c) germinating the somatic embryo of (b) for about 14 to about 60 days to form a plantlet;
• and
• (d) allowing the plantlet of (c) to grow into a Poaceae plant.