Theobromine synthase polypeptide of coffee plant and the gene encoding said polypeptide

Abstract

According to the present invention, the polypeptide of theobromine synthase derived from coffea arabica and the gene encoding said polypeptide are provided. As theobromine synthase participates in biosynthesis of caffeine, caffeineless coffee would be obtained by preparing a transformed plant, wherein expression of gene encoding said enzyme is inhibited.

What is claimed is:  
     
         1 . A polypeptide consisting of an amino acid sequence of following (a) or (b):  
       (a) an amino acid sequence defined by amino acid numbers from 1 to 378 shown in SEQ ID NO: 1 in a Sequence List,  
       (b) an amino acid sequence in which a part of said amino acid sequence (a) is deleted or another amino acid sequence is added to said amino acid sequence (a) or a part of amino acid sequence (a) is substituted with another amino acid sequence, the amino acid sequence (b) having the activity to biosynthesize theobromine using 7-methylxanthine as the substrate.  
     
     
         2 . A polypeptide consisting of an amino acid sequence exhibiting at least 90% of homology with an amino acid sequence defined by amino acid numbers from 1 to 378 shown in SEQ ID NO: 1 in a Sequence List.  
     
     
         3 . A gene encoding the polypeptide according to claims  1  or  2 .  
     
     
         4 . A gene consisting of a base sequence of following (c), (d) or (e):  
       (c) a base sequence defined by base numbers from 1 to 1298 shown in SEQ ID NO: 2 in a Sequence List,  
       (d) a base sequence in which a part of base sequence (c) is deleted or another base sequence is added to said base sequence (c) or a part of base sequence (c) is substituted with another base sequence, the base sequence (d) encoding a polypeptide having the activity to biosynthesize theobromine using 7-methylxanthine as the substrate.  
       (e) a base sequence that hybridizes with said base sequence (c) under stringent condition, the base sequence (e) encoding a polypeptide having the activity to biosynthesize theobromine using 7-methylxanthine as the substrate.  
     
     
         5 . A gene consisting of a base sequence exhibiting at least 90% of homology with a base sequence defined by base numbers from 1 to 1298 shown in SEQ ID NO: 2 in a Sequence List.  
     
     
         6 . A transformed plant wherein expression of the gene according to  claims 3  to  5  is decreased in the plant to inhibit biosynthsis of theobromine.  
     
     
         7 . The transformed plant according to  claim 6 , wherein antisense gene method is utilized to inhibit biosynthesis of theobromine.  
     
     
         8 . The transformed plant according to  claim 6 , wherein said plant is selected from the group consisting of  Coffea arabica, Coffea canephora, Coffea liberica  and  Coffea dewevrei.    
     
     
         9 . A seed obtained from the transformed plant according to claims  6  or  8 .  
     
     
         10 . A transformed plant wherein gene according to  claims 3  to  5  is introduced in the plant to increase biosynthsis of theobromine.  
     
     
         11 . The transformed plant according to  claim 10 , wherein said plant is selected from the group consisting of  Coffea arabica, Coffea canephora, Coffea liberica  and  Coffea dewevrei.    
     
     
         12 . A seed obtained from the transformed plant according to claims  10  or  11 .  
     
     
         13 . A method for production of a transformed plant in which biosynthesis of theobromine is inhibited in the plant by decreasing expression of the gene according to claims  3  or  5 .  
     
     
         14 . The method according to  claim 13 , wherein antisense gene method is utilized to inhibit biosynthesis of theobromine.  
     
     
         15 . A method for production of a transformed plant in which biosynthesis of theobromine is enhanced in the plant by enhancing expression of the gene according to claims  3  or  5 .