Plants having altered agronomic characteristics under nitrogen limiting conditions and related constructs and methods involving genes encoding lnt2 polypeptides and homologs thereof

Abstract

Isolated polynucleotides and polypeptides and recombinant DNA constructs particularly useful for altering agronomic characteristics of plants under nitrogen limiting conditions, compositions (such as plants or seeds) comprising these recombinant DNA constructs, and methods utilizing these recombinant DNA constructs. The recombinant DNA construct comprises a polynucleotide operably linked to a promoter functional in a plant, wherein said polynucleotide encodes an LNT2 polypeptide.

What is claimed is: 
     
         1 . A plant comprising in its genome a recombinant DNA construct comprising a polynucleotide operably linked to at least one regulatory element, wherein said polynucleotide encodes a polypeptide having an amino acid sequence of at least 50% sequence identity, based on the Clustal V method of alignment, when compared to SEQ ID NO:18, 20, 24, 26, 28, 30, or 32, and wherein said plant exhibits increased nitrogen stress tolerance when compared to a control plant not comprising said recombinant DNA construct. 
     
     
         2 . The plant of  claim 1 , wherein the plant is a maize plant or a soybean plant. 
     
     
         3 . A plant comprising in its genome a recombinant DNA construct comprising:
 (a) a polynucleotide operably linked to at least one regulatory element, wherein said polynucleotide encodes a polypeptide having an amino acid sequence of at least 50% sequence identity, based on the Clustal V method of alignment, when compared to SEQ ID NO: 18, 20, 24, 26, 28, 30, or 32; or   (b) a suppression DNA construct comprising at least one regulatory element operably linked to:
 (i) all or part of: (A) a nucleic acid sequence encoding a polypeptide having an amino acid sequence of at least 50% sequence identity, based on the Clustal V method of alignment, when compared to SEQ ID NO: 18, 20, 24, 26, 28, 30, or 32, or (B) a full complement of the nucleic acid sequence of (b)(i)(A); or 
 (ii) a region derived from all or part of a sense strand or antisense strand of a target gene of interest, said region having a nucleic acid sequence of at least 50% sequence identity, based on the Clustal V method of alignment, when compared to said all or part of a sense strand or antisense strand from which said region is derived, and wherein said target gene of interest encodes an LNT2 polypeptide, 
   and wherein said plant exhibits an alteration of at least one agronomic characteristic when compared to a control plant not comprising said recombinant DNA construct.   
     
     
         4 . The plant of  claim 3 , wherein the plant is a maize plant or a soybean plant. 
     
     
         5 . The plant of  claim 3 , wherein said plant exhibits said alteration of said at least one agronomic characteristic when compared, under nitrogen limiting conditions, to said control plant not comprising said recombinant DNA construct. 
     
     
         6 . The plant of  claim 5 , wherein the plant is a maize plant or a soybean plant. 
     
     
         7 . The plant of  claim 3 , wherein said at least one agronomic characteristic is selected from the group consisting of greenness, yield, growth rate, biomass, fresh weight at maturation, dry weight at maturation, fruit yield, seed yield, total plant nitrogen content, fruit nitrogen content, seed nitrogen content, nitrogen content in vegetative tissue, whole plant amino acid content, vegetative tissue free amino acid content, fruit free amino acid content, seed free amino acid content, total plant protein content, fruit protein content, seed protein content, protein content in a vegetative tissue, drought tolerance, nitrogen uptake, resistance to root lodging, harvest index, stalk lodging, plant height, ear height, and ear length. 
     
     
         8 . The plant of  claim 7 , wherein the plant is a maize plant or a soybean plant. 
     
     
         9 . The plant of  claim 3 , wherein said plant exhibits an increase of said at least one agronomic characteristic when compared to said control plant. 
     
     
         10 . The plant of  claim 9 , wherein the plant is a maize plant or a soybean plant. 
     
     
         11 . A method of increasing nitrogen stress tolerance in a plant, comprising:
 (a) introducing into a regenerable plant cell a recombinant DNA construct comprising a polynucleotide operably linked to at least one regulatory sequence, wherein the polynucleotide encodes a polypeptide having an amino acid sequence of at least 50% sequence identity, based on the Clustal V method of alignment, when compared to SEQ ID NO: 18, 20, 24, 26, 28, 30, or 32; and   (b) regenerating a transgenic plant from the regenerable plant cell after step (a), wherein the transgenic plant comprises in its genome the recombinant DNA construct and exhibits increased nitrogen stress tolerance when compared to a control plant not comprising the recombinant DNA construct.   
     
     
         12 . The method of  claim 11 , further comprising:
 (c) obtaining a progeny plant derived from the transgenic plant, wherein said progeny plant comprises in its genome the recombinant DNA construct and exhibits increased nitrogen stress tolerance when compared to a control plant not comprising the recombinant DNA construct.   
     
     
         13 . A method of evaluating nitrogen stress tolerance in a plant, comprising:
 (a) introducing into a regenerable plant cell a recombinant DNA construct comprising a polynucleotide operably linked to at least one regulatory sequence, wherein the polynucleotide encodes a polypeptide having an amino acid sequence of at least 50% sequence identity, based on the Clustal V method of alignment, when compared to SEQ ID NO: 18, 20, 24, 26, 28, 30, or 32;   (b) regenerating a transgenic plant from the regenerable plant cell after step (a), wherein the transgenic plant comprises in its genome the recombinant DNA construct; and   (c) evaluating the transgenic plant for nitrogen stress tolerance compared to a control plant not comprising the recombinant DNA construct.   
     
     
         14 . The method of  claim 13 , further comprising:
 (d) obtaining a progeny plant derived from the transgenic plant, wherein the progeny plant comprises in its genome the recombinant DNA construct; and   (e) evaluating the progeny plant for nitrogen stress tolerance compared to a control plant not comprising the recombinant DNA construct.   
     
     
         15 . A method of evaluating nitrogen stress tolerance in a plant, comprising:
 (a) introducing into a regenerable plant cell a recombinant DNA construct comprising a polynucleotide operably linked to at least one regulatory sequence, wherein the polynucleotide encodes a polypeptide having an amino acid sequence of at least 50% sequence identity, based on the Clustal V method of alignment, when compared to SEQ ID NO: 18, 20, 24, 26, 28, 30, or 32;   (b) regenerating a transgenic plant from the regenerable plant cell after step (a), wherein the transgenic plant comprises in its genome the recombinant DNA construct;   (c) obtaining a progeny plant derived from the transgenic plant, wherein the progeny plant comprises in its genome the recombinant DNA construct; and   (d) evaluating the progeny plant for nitrogen stress tolerance compared to a control plant not comprising the recombinant DNA construct.   
     
     
         16 . A method of determining an alteration of an agronomic characteristic in a plant, comprising:
 (a) introducing into a regenerable plant cell a recombinant DNA construct comprising a polynucleotide operably linked to at least one regulatory sequence, wherein the polynucleotide encodes a polypeptide having an amino acid sequence of at least 50% sequence identity, based on the Clustal V method of alignment, when compared to SEQ ID NO: 18, 20, 24, 26, 28, 30, or 32;   (b) regenerating a transgenic plant from the regenerable plant cell after step (a), wherein the transgenic plant comprises in its genome the recombinant DNA construct; and   (c) determining whether the transgenic plant exhibits an alteration of at least one agronomic characteristic when compared to a control plant not comprising the recombinant DNA construct.   
     
     
         17 . The method of  claim 16 , further comprising:
 (d) obtaining a progeny plant derived from the transgenic plant, wherein the progeny plant comprises in its genome the recombinant DNA construct; and   (e) determining whether the progeny plant exhibits an alteration of at least one agronomic characteristic when compared to a control plant not comprising the recombinant DNA construct.   
     
     
         18 . The method of  claim 16 , wherein said determining step (c) comprises determining whether the transgenic plant exhibits an alteration of at least one agronomic characteristic when compared, under nitrogen limiting conditions, to a control plant not comprising the recombinant DNA construct. 
     
     
         19 . The method of  claim 17 , wherein said determining step (e) comprises determining whether the progeny plant exhibits an alteration of at least one agronomic characteristic when compared, under nitrogen limiting conditions, to a control plant not comprising the recombinant DNA construct. 
     
     
         20 . A method of determining an alteration of an agronomic characteristic in a plant, comprising:
 (a) introducing into a regenerable plant cell a recombinant DNA construct comprising a polynucleotide operably linked to at least one regulatory sequence, wherein the polynucleotide encodes a polypeptide having an amino acid sequence of at least 50% sequence identity, based on the Clustal V method of alignment, when compared to SEQ ID NO: 18, 20, 24, 26, 28, 30, or 32;   (b) regenerating a transgenic plant from the regenerable plant cell after step (a), wherein the transgenic plant comprises in its genome the recombinant DNA construct;   (c) obtaining a progeny plant derived from the transgenic plant, wherein the progeny plant comprises in its genome the recombinant DNA construct; and   (d) determining whether the progeny plant exhibits an alteration of at least one agronomic characteristic when compared to a control plant not comprising the recombinant DNA construct.   
     
     
         21 . The method of  claim 20 , wherein said determining step (d) comprises determining whether the transgenic plant exhibits an alteration of at least one agronomic characteristic when compared, under nitrogen limiting conditions, to a control plant not comprising the recombinant DNA construct. 
     
     
         22 . A method of determining an alteration of an agronomic characteristic in a plant, comprising:
 (a) introducing into a regenerable plant cell a suppression DNA construct comprising at least one regulatory element operably linked to:
 (i) all or part of: (A) a nucleic acid sequence encoding a polypeptide having an amino acid sequence of at least 50% sequence identity, based on the Clustal V method of alignment, when compared to SEQ ID NO:18, 20, 24, 26, 28, 30, or 32, or (B) a full complement of the nucleic acid sequence of (b)(i)(A); or 
 (ii) a region derived from all or part of a sense strand or antisense strand of a target gene of interest, said region having a nucleic acid sequence of at least 50% sequence identity, based on the Clustal V method of alignment, when compared to said all or part of a sense strand or antisense strand from which said region is derived, and wherein said target gene of interest encodes an LNT2 polypeptide; 
   (b) regenerating a transgenic plant from the regenerable plant cell after step (a), wherein the transgenic plant comprises in its genome the suppression DNA construct; and   (c) determining whether the transgenic plant exhibits an alteration of at least one agronomic characteristic when compared to a control plant not comprising the suppression DNA construct.   
     
     
         23 . The method of  claim 22 , wherein said determining step (c) comprises determining whether the transgenic plant exhibits an alteration of at least one agronomic characteristic when compared, under nitrogen limiting conditions, to a control plant not comprising the suppression DNA construct. 
     
     
         24 . The method of  claim 22 , further comprising:
 (d) obtaining a progeny plant derived from the transgenic plant, wherein the progeny plant comprises in its genome the suppression DNA construct; and   (e) determining whether the progeny plant exhibits an alteration of at least one agronomic characteristic when compared to a control plant not comprising the suppression DNA construct.   
     
     
         25 . The method of  claim 24 , wherein said determining step (e) comprises determining whether the progeny plant exhibits an alteration of at least one agronomic characteristic when compared, under nitrogen limiting conditions, to a control plant not comprising the suppression DNA construct. 
     
     
         26 . A method of determining an alteration of an agronomic characteristic in a plant, comprising:
 (a) introducing into a regenerable plant cell a suppression DNA construct comprising at least one regulatory element operably linked to:
 (i) all or part of: (A) a nucleic acid sequence encoding a polypeptide having an amino acid sequence of at least 50% sequence identity, based on the Clustal V method of alignment, when compared to SEQ ID NO: 18, 20, 24, 26, 28, 30, or 32, or (B) a full complement of the nucleic acid sequence of (b)(i)(A); or 
 (ii) a region derived from all or part of a sense strand or antisense strand of a target gene of interest, said region having a nucleic acid sequence of at least 50% sequence identity, based on the Clustal V method of alignment, when compared to said all or part of a sense strand or antisense strand from which said region is derived, and wherein said target gene of interest encodes an LNT2 polypeptide; 
   (b) regenerating a transgenic plant from the regenerable plant cell after step (a), wherein the transgenic plant comprises in its genome the suppression DNA construct and exhibits an alteration of at least one agronomic trait when compared to a control plant not comprising the suppression DNA construct;   (c) obtaining a progeny plant derived from the transgenic plant, wherein the progeny plant comprises in its genome the suppression DNA construct; and   (d) determining whether the progeny plant exhibits an alteration of at least one agronomic characteristic when compared to a control plant not comprising the suppression DNA construct.   
     
     
         27 . The method of  claim 26 , wherein said determining step (d) comprises determining whether the transgenic plant exhibits an alteration of at least one agronomic characteristic when compared, under nitrogen limiting conditions, to a control plant not comprising the recombinant DNA construct. 
     
     
         28 . An isolated polynucleotide comprising:
 (i) a nucleic acid sequence encoding a polypeptide having an amino acid sequence of at least 85% sequence identity, based on the Clustal V method of alignment, when compared to SEQ ID NO:18, 24, or 26; or   (ii) a full complement of the nucleic acid sequence of (i).   
     
     
         29 . The isolated polynucleotide of  claim 28 , wherein said polypeptide has an amino acid sequence of at least 90% sequence identity, based on the Clustal V method of alignment, when compared to SEQ ID NO:18, 24, or 26. 
     
     
         30 . The isolated polynucleotide of  claim 28 , wherein said polypeptide has an amino acid sequence of at least 95% sequence identity, based on the Clustal V method of alignment, when compared to SEQ ID NO:18, 24, or 26. 
     
     
         31 . The isolated polynucleotide of  claim 28 , wherein the polypeptide sequence comprises SEQ ID NO:18, 24, or 26. 
     
     
         32 . The isolated polynucleotide of  claim 28 , wherein the nucleic acid sequence comprises SEQ ID NO:17, 23, or 25.