Corn plants and seed enhanced for asparagine and protein

Abstract

The present invention relates to a corn plant and seed with enhanced levels of protein and amino acids. The invention also relates to DNA constructs that provide expression in transgenic corn cells of an asparagine synthetase enzyme. The DNA constructs are used in a method to produce transgenic corn plants and seeds and to select for plants and seeds with enhanced levels of protein and amino acids.

1 . An isolated nucleic acid sequence selected from the group consisting of:
 (a) a nucleic acid sequence comprising the sequence of SEQ ID NO:50;   (b) a nucleic acid sequence with at least about 90% sequence identity to the sequence of SEQ ID NO:50, wherein the nucleic acid sequence encodes a polypeptide with asparagine synthetase activity;   (c) a nucleic acid sequence that encodes the polypeptide sequence of SEQ ID NO:51;   (d) a nucleic acid sequence that encodes a polypeptide with at least about 90% sequence identity to the polypeptide sequence of SEQ ID NO:51, wherein the polypeptide has asparagine synthetase activity; and   (e) a nucleic acid sequence that hybridizes to a sequence of (a)-(d) under high stringency conditions of about 0.2×SSC and 65° C., wherein the nucleic acid sequence encodes a polypeptide comprising asparagine synthetase activity.   
     
     
         2 . The isolated nucleic acid sequence of  claim 1 , further defined as operably linked to a heterologous regulatory element. 
     
     
         3 . The isolated nucleic acid sequence of  claim 1 , further defined as operably linked to a heterologous promoter functional in plants. 
     
     
         4 . A transgenic plant cell transformed with the isolated nucleic acid sequence of  claim 1 . 
     
     
         5 . A transgenic plant transformed with the isolated nucleic acid sequence of  claim 1 , or a part thereof. 
     
     
         6 . The transgenic plant of  claim 5 , further defined as a corn plant. 
     
     
         7 . A transgenic seed comprising the isolated nucleic acid sequence of  claim 1 . 
     
     
         8 . A transgenic corn seed with an increased asparagine and/or protein content comprising in its genome a DNA construct comprising a polynucleotide encoding an AsnS4 asparagine synthetase polypeptide operably linked to a heterologous promoter, wherein said seed has an increased asparagine and/or protein content relative to the protein level of a seed of the same variety as the transgenic corn seed but not containing said DNA construct in its genome. 
     
     
         9 . The transgenic corn seed of  claim 8 , wherein the polynucleotide encoding an asparagine synthetase polypeptide comprises the isolated nucleic acid sequence of  claim 1 . 
     
     
         10 . The transgenic corn seed of  claim 8 , wherein said asparagine synthetase polypeptide comprises SEQ ID NO:51. 
     
     
         11 . The transgenic corn seed of  claim 8 , wherein said polynucleotide comprises the nucleic acid sequence of SEQ ID NO:50. 
     
     
         12 . The transgenic corn seed of  claim 8 , wherein said promoter is a rice actin 1 promoter. 
     
     
         13 . A method of producing a transgenic corn plant with increased asparagine comprising
 a) introducing into a corn plant a heterologous DNA construct comprising a promoter molecule functional in a corn cell operably linked to a DNA molecule encoding an asparagine synthetase polypeptide;   b) growing the plant to maturity; and   c) harvesting seed from the plant.   
     
     
         14 . The method of  claim 13 , wherein said polynucleotide encoding a heterologous asparagine synthetase comprises the isolated nucleic acid sequence of  claim 1 . 
     
     
         15 . The method of  claim 13 , wherein said asparagine synthetase polypeptide comprises the amino acid sequence of SEQ ID NO:51. 
     
     
         16 . The method of  claim 13 , wherein said DNA molecule comprises the nucleic acid sequence of SEQ ID NO:50. 
     
     
         17 . The method of  claim 13 , further comprising the step of:
 f) selecting a seed with increased protein.   
     
     
         18 . Corn meal produced from the plant of  claim 6 , wherein the corn meal comprises the isolated nucleic acid sequence of  claim 1 . 
     
     
         19 . The corn meal of  claim 18 , wherein said nucleic acid sequence comprises the sequence of SEQ ID NO:50. 
     
     
         20 . The corn meal of  claim 18 , wherein said nucleic acid sequence encodes a polypeptide of SEQ ID NO:51. 
     
     
         21 . A method of producing food or feed comprising obtaining the transgenic plant of  claim 5  and producing food or feed from the plant or a part thereof. 
     
     
         22 . Food or feed produced by the method of  claim 21 , wherein the food or feed comprises the isolated nucleic acid sequence of  claim 1 .