Modification of plant metabolism

Abstract

A transgenic plant is prepared by a method n which a plant cell is transformed with a chimaeric gene comprising a promoter and a gene encoding a polypeptide which displays the activity of an enzyme which regulates the amount of a metabolic intermediate in glycolysis or in a pathway for the synthesis or degradation of starch, sucrose or reducing sugar from a glycotyltic intermediate. In stored potatoes the subject of the invention an increased level of phosphofructokinase results in reduced accumulations of sugars in the tubers.

1 . A process for the preparation of a transgenic plant, which method comprises: 
 (i) transforming a plant cell with a chimaeric gene comprising (a) a suitable promoter and (b) a coding sequence the product of which causes modification of the amount of a metabolic intermediate in glycolysis or in a pathway for the synthesis or degradation of starch, sucrose or reducing sugar; and    (ii) regenerating a plant from the transformed cell.    
     
     
         2 . A process according to  claim 1 , wherein the coding sequence (b) encodes an enzyme selected from phosphofructokinase, pyruvate kinase, acid invertase, starch synthase, adenine diphosphoglucose, sucrose synthase, 6-pyrophofructokinase (pyrophosphate) or sucrose phosphate synthetase.  
     
     
         3 . A process according to  claim 1  or  2 , wherein the coding sequence (b) is from a microbial gene.  
     
     
         4 . A process according to  claim 3 , wherein the coding sequence (b) is from a bacterial gene.  
     
     
         5 . A process according to  claim 1 , wherein the coding sequence (b) encodes for phosphofructokinase.  
     
     
         6 . A process according to  claim 1 , wherein the coding sequence (b) encodes for two or more enzymes.  
     
     
         7 . A process according to  claim 1 , wherein the plant cell transformed in step (i) is a cell of 
 (A) a monocotyledonous species selected from the group consisting of barley, wheat, maize and rice; or    (B) a dicotyledonous species selected from the group consisting of cotton, lettuce, melon, pea, petunia, potato, rape, soyabean, sugar beet, sunflower, tobacco and tomato.    
     
     
         8 . A process according to  claim 7 , wherein the plant cell transformed is a potato cultivar cell, said cultivar is selected from the group consisting of Desiree, Maris Bard, Record and Russet Burbank.  
     
     
         9 . A chimaeric gene as defined in  claim 1 .  
     
     
         10 . A vector which comprises a chimaeric gene as defined in  claim 1  such that the chimaeric gene is capable of being expressed in a plant cell transformed with the vector.  
     
     
         11 . A vector according to  claim 10 , which is a plasmid.  
     
     
         12 . A plant cell which harbours a chimaeric gene as defined in  claim 1  such that the chimaeric gene is capable of being expressed therein.  
     
     
         13 . A transgenic plant which harbors in its cells a chimaeric gene as defined in  claim 1  such that the chimaeric gene is capable of being expressed in the cells of the plant.  
     
     
         14 . A plant according to  claim 13 , which is a potato.  
     
     
         15 . Seed obtained from a transgenic plant as claimed in  claim 13  or  14 .  
     
     
         16 . Tubers obtained from a potato as claimed in  claim 14.