US 8,273,955 B2 · Spontaneous nodulation in plants

Abstract

Formation of nitrogen fixing root nodules in legumes is induced by perception of lipochitin-oligosaccharide signal molecules secreted by compatible Rhizobium bacteria, which triggers a common symbiotic pathway. The present invention provides a spontaneous nodule formation (snf1-5g) mutant, in which the formation of symbiotic nodules is deregulated, leading to nodule development in the absence as well as in the presence of Rhizobium bacteria and/or exogenous rhizobial signals. The invention further provides an isolated DNA sequence encoding a mutant chimeric Ca2+/calmodulin dependent protein kinase whose activity results in this &grave;gain of function′ phenotype of spontaneous nodule formation. Furthermore the snf1-5g gene is shown to confer a spontaneous nodule formation phenotype to plants having a nodulation deficient genetic background. A gene of the invention, that confers a spontaneous nodulation phenotype, has utility for the transfer and establishment of nitrogen fixing capability in non-nodulating plants, and thereby reducing the nitrogen fertilizer dependence of non-nodulating crop plants.

Claims30

Dependent claims

A genetically modified and non-naturally occurring plant comprising a nucleotide sequence encoding a modified Calcium and Calmodulin-dependent protein kinase (CCaMK) polypeptide which is autophosphorylation deficient and having at least 85% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NO:

7, SEQ ID NO:
8, SEQ ID NO:
9, SEQ ID NO:
10, SEQ ID NO:
11, SEQ ID NO:
15, SEQ ID NO:
26, and SEQ ID NO:
27;
wherein amino acid residue designated as Xaa in said amino acid sequence is at an autophosphorylation site in a native and unmodified CCaMK polypeptide;
wherein said modified CCaMK is autophosphorylation-deficient at the amino acid residue corresponding to said Xaa;
wherein said Xaa is selected from the group consisting of isoleucine, leucine, valine, methionine, alanine, phenylalanine, tyrosine, tryptophan, arginine, lysine, glycine, histidine, aspartate, asparagine, glutamate, glutamine, proline, and cysteine;
and wherein expression of said modified CCaMK polypeptide in said genetically modified plant results in spontaneous nodule formation which is independent of Rhizobium-induction and exogenous Nod-factor signalling in said plant.

9 more elements

A method for producing a genetically modified and non-naturally occurring plant having spontaneous nodule formation which is independent of Rhizobium-induction and exogenous Nod-factor signalling, the method comprising the steps of:

a) mutating a plant's genome;
b) obtaining progeny of mutated plants from the mutated plant of step a);
and
c) selecting a mutant plant from the progeny of mutated plants of step b) that expresses a nucleotide sequence encoding a modified Calcium and Calmodulin-dependent protein kinase (CCaMK) polypeptide which is autophosphorylation deficient and having at least 85% sequence identity to an amino acid sequence selected from the group consisting of SEQ ID NO:
7, SEQ ID NO:
8, SEQ ID NO:
9, SEQ ID NO:
10, SEQ ID NO:
11, SEQ ID NO:
15, SEQ ID NO:
26, and SEQ ID NO:
27;
wherein amino acid residue designated as Xaa in said amino acid sequence is at an autophosphorylation site in a native and unmodified CCaMK polypeptide;
wherein said modified CCaMK is autophosphorylation-deficient at the amino acid residue corresponding to said Xaa;
wherein said Xaa is selected from the group consisting of isoleucine, leucine, valine, methionine, alanine, phenylalanine, tyrosine, tryptophan, arginine, lysine, glycine, histidine, aspartate, asparagine, glutamate, glutamine, proline, and cysteine;
and wherein expression of said modified CCaMK polypeptide in said genetically modified plant results in spontaneous nodule formation which is independent of Rhizobium-induction and exogenous Nod-factor signalling in said selected mutant plant.

13 more elements

Dependencies are inferred from the claim text.

Spontaneous nodulation in plants

Life of this patent

Spontaneous nodulation in plants

Life of this patent

Abstract

Claims30