Promoting regeneration and transformation in plants

A method of inducing shoot formation from at least one plant cell, the method comprising:

• (a) incubating the at least one plant cell in the presence of sodium nitroprusside (SNP);
• (b) introducing into the at least one plant cell to be used in step (a) or into at least one cell of the callus obtained in step (a) an expression cassette comprising a coding nucleotide sequence selected from
• (i) the nucleotide sequence of SEQ ID NO:
• 1;
• and
• (ii) a nucleotide sequence encoding a polypeptide having the amino acid sequence of SEQ ID NO:
• 2,
• wherein the nucleotide sequence is operably linked to a heterologous constitutive regulatory element or a heterologous inducible regulatory element;
• and
• (c) cultivating the callus obtained in step (b) under conditions promoting growth of shoots out of the callus, wherein in the callus the polypeptide is expressed from the expression cassette constitutively or upon induction of the heterologous inducible regulatory element.

A method of increasing plant regeneration from at least one plant cell, the method comprising:

• (a) incubating the at least one plant cell in the presence of sodium nitroprusside (SNP);
• (b) introducing into the at least one plant cell to be used in step (a) or into at least one cell of the callus obtained in step (a) an expression cassette comprising a coding nucleotide sequence selected from
• (i) the nucleotide sequence of SEQ ID NO:
• 1;
• and
• (ii) a nucleotide sequence encoding a polypeptide having the amino acid sequence of SEQ ID NO:
• 2,
• wherein the nucleotide sequence is operably linked to a heterologous constitutive regulatory element or a heterologous inducible regulatory element;
• and
• (c) cultivating the callus obtained in step (b) under conditions promoting growth of embryos and/or shoots out of the callus, wherein in the callus the polypeptide is expressed from the expression cassette constitutively or upon induction of the heterologous inducible regulatory element,
• wherein the plant regeneration rate is increased relative to a plant cell that has not been incubated in the presence of SNP and/or has not had the expression cassette of step (b) introduced.

A method of producing a plant from at least one plant cell, the method comprising:

• (a) incubating the at least one plant cell in the presence of sodium nitroprusside (SNP);
• (b) introducing into the at least one plant cell to be used in step (a) or into at least one cell of the callus obtained in step (a) an expression cassette comprising a coding nucleotide sequence selected from
• (i) the nucleotide sequence of SEQ ID NO:
• 1;
• and
• (ii) a nucleotide sequence encoding a polypeptide having the amino acid sequence of SEQ ID NO:
• 2,
• wherein the nucleotide sequence is operably linked to a heterologous constitutive regulatory element or a heterologous inducible regulatory element;
• (c) cultivating the callus obtained in step (b) under conditions promoting growth of embryos and/or shoots out of the callus, wherein in the callus the polypeptide is expressed from the expression cassette constitutively or upon induction of the heterologous inducible regulatory element;
• and
• (d) regenerating a plant from the embryo and/or shoot resulting from step (c).

A method of promoting somatic embryogenesis or organogenesis of a plant, comprising the following steps:

• (a) inducing callus formation from at least one plant cell comprising incubating the at least one plant cell in the presence of sodium nitroprusside (SNP), and
• (b) introducing into the at least one plant cell to be used in step (a) or into at least one cell of the callus obtained in step (a) an expression cassette comprising a nucleotide sequence selected from:
• (i) the nucleotide sequence of SEQ ID NO:
• 1;
• and
• (ii) a nucleotide sequence encoding a polypeptide having the amino acid sequence of SEQ ID NO:
• 2,
• wherein the nucleotide sequence is operably linked to a first heterologous constitutive regulatory element or a first heterologous inducible regulatory element;
• (c) cultivating the callus obtained in step (b) under conditions promoting growth of embryos and/or shoots out of the callus, wherein in the callus the polypeptide is expressed from the expression cassette constitutively or upon induction of the heterologous inducible regulatory element;
• and
• (d) introducing into the at least one plant cell
• (I) the expression cassette further comprising a second nucleotide sequence selected from:
• (i) the nucleotide sequence of SEQ ID NO:
• 12, and
• (ii) a nucleotide sequence encoding a polypeptide having the amino acid sequence of SEQ ID NO:
• 13,
• wherein the second nucleotide sequence is operably linked to the first heterologous constitutive regulatory element or the first heterologous inducible regulatory element or to a second heterologous constitutive regulatory element or a second heterologous inducible regulatory element;
• or
• (II) an mRNA encoding a polypeptide having the amino acid sequence of SEQ ID NO:
• 13;
• or
• (III) a polypeptide having the amino acid sequence of SEQ ID NO:
• 13;
• or
• (IV) inducing in said at least one plant cell an enhanced expression level of an endogenous gene encoding the polypeptide having the amino acid sequence of SEQ ID NO:
• 13, and
• wherein cultivating the callus in step (c) to promote growth of embryos and/or shoots out of the callus is carried out under conditions wherein in the callus the polypeptide having the amino acid sequence of SEQ ID NO:
• 2 is expressed from the expression cassette, and the polypeptide having the amino acid sequence of SEQ ID NO:
• 13 is expressed from the expression cassette, is translated from introduced mRNA, is expressed at an enhanced level from the endogenous gene, or is present.