Plant raffinose saccharide biosynthetic enzymes

Abstract

This invention relates to an isolated nucleic acid fragment encoding a galactinol synthase. The invention also relates to the construction of a chimeric gene encoding all or a portion of the galactinol synthase, in sense or antisense orientation, wherein expression of the chimeric gene results in production of altered levels of the galactinol synthase in a transformed host cell.

1 . An isolated polynucleotide comprising: 
 (a) a nucleotide sequence encoding a polypeptide having galactinol synthase activity, wherein the amino acid sequence of the polypeptide and the amino acid sequence of SEQ ID NO:2 or SEQ ID NO:4 have at least 80% identity based on the Clustal alignment method, or    (b) the complement of the nucleotide sequence.    
     
     
         2 . The isolated polynucleotide of  claim 1 , wherein the amino acid sequence of the polypeptide and the amino acid sequence of SEQ ID NO:2 or SEQ ID NO:4 have at least 85% identity based on the Clustal alignment method.  
     
     
         3 . The isolated polynucleotide of  claim 1 , wherein the amino acid sequence of the polypeptide and the amino acid sequence of SEQ ID NO:2 or SEQ ID NO:4 have at least 90% identity based on the Clustal alignment method.  
     
     
         4 . The isolated polynucleotide of  claim 1 , wherein the amino acid sequence of the polypeptide and the amino acid sequence of SEQ ID NO:2 or SEQ ID NO:4 have at least 95% identity based on the Clustal alignment method.  
     
     
         5 . The isolated polynucleotide of  claim 1 , wherein the polypeptide comprises the amino acid sequence of SEQ ID NO:2 or SEQ ID NO:4.  
     
     
         6 . The isolated polynucleotide of  claim 1 , wherein the nucleotide sequence comprises the nucleotide sequence of SEQ ID NO:1 or SEQ ID NO:3.  
     
     
         7 . An isolated polynucleotide comprising a nucleotide sequence containing at least 30 nucleotides, wherein the nucleotide sequence containing at least 30 nucleotides is comprised by the polynucleotide of  claim 1 .  
     
     
         8 . The polynucleotide of  claim 7 , wherein the nucleotide sequence containing at least 30 nucleotides contains at least 40 nucleotides.  
     
     
         9 . The polynucleotide of  claim 7 , wherein the nucleotide sequence containing at least 30 nucleotides contains at least 60 nucleotides.  
     
     
         10 . A chimeric gene comprising the polynucleotide of  claim 1  or  claim 7  operably linked to a regulatory sequence.  
     
     
         11 . A vector comprising the polynucleotide of  claim 1  or  claim 7 .  
     
     
         12 . A method for transforming a cell comprising transforming a cell with the polynucleotide of  claim 1  or  claim 7 .  
     
     
         13 . A cell comprising the chimeric gene of  claim 10 .  
     
     
         14 . A method for producing a transgenic plant comprising transforming a plant cell with the polynucleotide of  claim 1  or  claim 7  and regenerating a plant from the transformed plant cell.  
     
     
         15 . A plant comprising the chimeric gene of  claim 10 .  
     
     
         16 . A seed comprising the chimeric gene of  claim 10 .  
     
     
         17 . An isolated polypeptide having galactinol synthase activity, wherein the amino acid sequence of the polypeptide and the amino acid sequence of SEQ ID NO:2 or SEQ ID NO:4 have at least 80% identity based on the Clustal alignment method.  
     
     
         18 . The polypeptide of  claim 17 , wherein the amino acid sequence of the polypeptide and the amino acid sequence of SEQ ID NO:2 or SEQ ID NO:4 have at least 85% identity based on the Clustal alignment method.  
     
     
         19 . The polypeptide of  claim 17 , wherein the amino acid sequence of the polypeptide and the amino acid sequence of SEQ ID NO:2 or SEQ ID NO:4 have at least 90% identity based on the Clustal alignment method.  
     
     
         20 . The polypeptide of  claim 17 , wherein the amino acid sequence of the polypeptide and the amino acid sequence of SEQ ID NO:2 or SEQ ID NO:4 have at least 95% identity based on the Clustal alignment method.  
     
     
         21 . The polypeptide of  claim 17 , wherein the amino acid sequence of the polypeptide comprises the amino acid sequence of SEQ ID NO:2 or SEQ ID NO:4.