Expression of sucrose phosphorylase in plants

Abstract

Introducing sucrose phosphorylase activity into plants by transformation with a gene for the enzyme increases the rate of sucrose hydrolysis, leading to increased starch, oil, and/protein levels. Sucrose phosphorylase genes from Streptococcus mutans and Leuconostoc mesenteroides have been found particularly advantageous for use in the present invention. Surprisingly, in potatoes transformed to express these genes in tubers, reduced bruise discoloration susceptibility and increased uniformity of starch deposition throughout the tuber are achieved.

1. A method of producing a transgenic plant, comprising the steps of:
 (a) stably transforming into the genome of a plant cell a recombinant, double-stranded DNA molecule comprising: 
 (i) a promoter which functions in cells of target plant tissue,  
 (ii) a structural DNA sequence obtained from a bacterium of the genus Leuconostoc that causes the production of an RNA sequence which encodes a sucrose phosphorylase enzyme,  
 (iii) a 3′ non-translated DNA sequence which functions in plant cells to cause transcriptional termination and the addition of polyadenylated nucleotides to the 3′ end of the RNA sequence;  
 
 (b) selecting for transformed plant cells; and  
 (c) regenerating from said transformed plant cells a genetically transformed plant, the genome of which contains said recombinant, double-stranded DNA molecule of step (a), wherein said genetically transformed plant exhibits a property one or more properties selected from the group consisting of containing a modified carbohydrate content; increased polysaccharide content; enhanced yield of harvested material; improved uniformity of the distribution of solids; increased oil content; increased protein content; and reduced susceptibility to bruising discoloration.  
 
     
     
       2. The method of  claim 1 , wherein said DNA sequence is obtained from Leuconostoc mesenteroides. 
     
     
       3. The method of  claim 2 , wherein said DNA sequence comprises the sequence shown in SEQ ID NO:6. 
     
     
       4. The method of  claim 1 , wherein said property is containing a modified carbohydrate content. 
     
     
       5. The method of  claim 4 , wherein said modified carbohydrate content is an increase in solids content. 
     
     
       6. The method of  claim 5 , wherein said genetically transformed plant is selected from the group consisting of potato and tomato. 
     
     
       7. The method of  claim 1 , wherein said property is improved uniformity of the distribution of solids. 
     
     
       8. The method of  claim 7 , wherein said genetically transformed plant is selected from the group consisting of potato and sweet potato. 
     
     
       9. The method of  claim 1 , wherein said property is reduced susceptibility to bruising discoloration. 
     
     
       10. The method of  claim 9 , wherein said genetically transformed plant is selected from the group consisting of potato, banana, apple, wheat, grape, and peach. 
     
     
       11. The method of  claim 1 , wherein said property is increased polysaccharide content. 
     
     
       12. The method of  claim 11 , wherein said genetically transformed plant is selected from the group consisting of maize, wheat, rice, tomato, potato, sweet potato, peanut, barley, cotton, strawberry, raspberry, and cassava. 
     
     
       13. The method of  claim 1 , wherein said property is enhanced yield of harvested material. 
     
     
       14. The method of  claim 13 , wherein said genetically transformed plant is selected from the group consisting of maize, wheat, rice, tomato, potato, sweet potato, peanut, barley, sugarbeet, sugarcane, apple, pear, orange, peach, grape, cotton, strawberry, raspberry, and cassava. 
     
     
       15. The method of  claim 1 , wherein said plant cell is selected from the group consisting of a potato plant cell, a maize plant cell, a rice plant cell, a wheat plant cell, a tomato plant cell, a barley plant cell, a sugarbeet plant cell, a sweetpotato plant cell, a peanut plant cell, a sugarcane plant cell, a grape plant cell, a pear plant cell, an apple plant cell, an orange plant cell, a cassava plant cell, a banana plant cell, a plantain plant cell, a cotton plant cell, a strawberry plant cell, a raspberry plant cell, and a peach plant cell. 
     
     
       16. The method of  claim 15 , wherein said plant cell is a potato plant cell. 
     
     
       17. The method of  claim 15 , wherein said plant cell is a maize plant cell. 
     
     
       18. The method of  claim 15 , wherein said plant cell is selected from the group consisting of a wheat plant cell, a barley plant cell, a rice plant cell, and a tomato plant cell. 
     
     
       19. A recombinant, double-stranded DNA molecule comprising in sequence:
 (a) a promoter which functions in cells of target plant tissue;  
 (b) a structural DNA sequence obtained from a bacterium of the genus Leuconostoc that causes the production of an RNA sequence which encodes a sucrose phosphorylase enzyme; and  
 (c) a 3′ non-translated region which functions in plant cells to cause transcriptional termination and the addition of polyadenylated nucleotides to the 3′ end of the RNA sequence.  
 
     
     
       20. The DNA molecule of  claim 19 , wherein said DNA sequence is obtained from Leuconostoc mesenteroides. 
     
     
       21. The DNA molecule of  claim 20 , wherein said DNA sequence comprises the sequence shown in SEQ ID NO:6. 
     
     
       22. The DNA molecule of  claim 19 , wherein said promoter is selected from the group consisting of a zein promoter, a patatin promoter, a rice glutelin promoter, the soybean 7s promoter, a promoter of a subunit of ADPglucose pyrophosphorylase, the TFM7 promoter, and the TFM9 promoter. 
     
     
       23. A transformed plant cell comprising a recombinant, doublestranded DNA molecule comprising in sequence:
 (a) a promoter which functions in said plant cell;  
 (b) a structural DNA sequence obtained from a bacterium of the genus Leuconostoc that causes the production of an RNA sequence which encodes a sucrose phosphorylase enzyme; and  
 (c) a 3′ non-translated region which functions in plant cells to cause transcriptional termination and the addition of polyadenylated nucleotides to the 3′ end of the RNA sequence.  
 
     
     
       24. The plant cell of  claim 23 , wherein said DNA sequence is obtained from Leuconostoc mesenteroides. 
     
     
       25. The plant cell of  claim 24 , wherein said DNA sequence comprises the sequence shown in SEQ ID NO:6. 
     
     
       26. The plant cell of  claim 23 , wherein said promoter is selected from the group consisting of a zein promoter, a patatin promoter, a rice glutelin promoter, the soybean 7s promoter, a promoter of a subunit of ADPglucose pyrophosphorylase, the TFM7 promoter, and the TFM9 promoter. 
     
     
       27. The plant cell of  claim 23 , wherein said plant cell is selected from the group consisting of a potato plant cell, a maize plant cell, a rice plant cell, a wheat plant cell, a tomato plant cell, a barley plant cell, a sugarbeet plant cell, a sweetpotato plant cell, a peanut plant cell, a sugarcane plant cell, a grape plant cell, a pear plant cell, an apple plant cell, an orange plant cell, a cassava plant cell, a banana plant cell, a plantain plant cell, and a peach plant cell. 
     
     
       28. A transformed plant comprising a recombinant, doublestranded DNA molecule comprising in sequence:
 (a) a promoter which functions in said plant cell;  
 (b) a structural DNA sequence obtained from a bacterium of the genus Leuconostoc that causes the production of an RNA sequence which encodes a sucrose phosphorylase enzyme; and  
 (c) a 3′ non-translated region which functions in plant cells to cause transcriptional termination and the addition of polyadenylated nucleotides to the 3′ end of the RNA sequence.  
 
     
     
       29. The plant of  claim 28 , wherein said DNA sequence is obtained from Leuconostoc mesenteroides. 
     
     
       30. The plant cell of claims claim  29 , wherein said DNA sequence comprises the sequence shown in SEQ ID NO:6. 
     
     
       31. The plant of  claim 28 , wherein said promoter is selected from the group consisting of a zein promoter, a patatin promoter, a rice glutelin promoter, the soybean 7s promoter, a promoter of a subunit of ADPglucose pyrophosphorylase, the TFM7 promoter, and the TFM9 promoter. 
     
     
       32. The plant of  claim 28 , wherein said plant is selected from the group consisting of a potato plant, a maize plant, a rice plant, a wheat plant, a tomato plant, a barley plant, a sugarbeet plant, a sweetpotato plant, a peanut plant, a sugarcane plant, a grape plant, a pear plant, an apple plant, an orange plant, a cassava plant, a banana plant, a plantain plant, and a peach plant. 
     
     
       33. The method of  claim 1 , wherein the polysaccharide is starch. 
     
     
       34. The method of  claim 11 , wherein the polysaccharide is starch. 
     
     
       35. The method of  claim 1 , wherein the property is increased oil content. 
     
     
       36. The method of  claim 1 , wherein the property is increased protein content. 
     
     
       37. The method of  claim 1 , wherein said plant cell is a canola plant cell. 
     
     
       38. The method of  claim 1 , wherein said plant cell is a soybean plant cell. 
     
     
       39. The plant cell of  claim 23 , wherein said plant cell is a canola plant cell. 
     
     
       40. The plant cell of  claim 23 , wherein said plant cell is a soybean plant cell. 
     
     
       41. The plant of  claim 28 , wherein said plant is a canola plant. 
     
     
       42. The plant of  claim 28 , wherein said plant is a soybean plant. 
     
     
       43. The method of  claim 1 , wherein the one or more properties are modified carbohydrate content and increased oil content. 
     
     
       44. The method of  claim 1 , wherein the one or more properties are modified carbohydrate content and increased protein content.