Expression of fructuse 1,6 bisphosphate aldolase in transgenic plants

Abstract

Fructose-1,6-bisphosphate aldolase (FDA) is an enzyme reversibly catalyzing the reaction converting triosephosphate into fructose-1,6-bisphosphate. In the leaf, this enzyme is located in the chloroplast (starch synthesis) and the cytosol (sucrose biosynthesis). Transgenic plants were generated that express the E. coli fda gene in the chloroplast to improve plant yield by increasing leaf starch biosynthetic ability in particular and sucrose production in general. Leaves from plants expressing the fda transgene showed a significantly higher starch accumulation, as compared to control plants expressing the null vector, particularly early in the photoperiod, but had lower leaf sucrose. Transgenic plants also had a significantly higher root mass. Furthermore, transgenic potatoes expressing fda exhibited improved uniformity of solids.

What is claimed is:  
     
         1 . A recombinant, double-stranded DNA molecule containing 
 a) a promoter functional in plant cells, and    b) a DNA sequence coding for a polypeptide having the enzymatic activity of a fructose-1,6-bisphosphate aldolase and operatively linked to the promoter in sense orientation.    
     
     
         2 . The DNA molecule according to  claim 1 , wherein the DNA sequence coding for a polypeptide having the enzymatic activity of a fructose-1,6-bisphosphate aldolase is derived from a prokaryotic organism.  
     
     
         3 . The DNA molecule according to  claim 2 , wherein the prokaryotic organism is  Escherichia coli.    
     
     
         4 . The DNA molecule according to  claim 1 , wherein the DNA sequence coding for a polypeptide having the enzymatic activity of a fructose-1,6-bisphosphate aldolase has at least about 60% identity with a prokaryotic DNA sequence coding for fructose-1,6-bisphosphate aldolase class II.  
     
     
         5 . The DNA molecule according to  claim 1 , wherein the DNA sequence coding for the polypeptide having the enzymatic activity of a fructose-1,6-bisphosphate aldolase is a sequence capable of hybridizing with the coding region depicted as SEQ ID NO.1.  
     
     
         6 . The DNA molecule according to  claim 1 , wherein the DNA sequence coding for a polypeptide having the enzymatic activity of a fructose-1,6-bisphosphate aldolase has at least about 60% identity with the coding region depicted as SEQ ID NO.1.  
     
     
         7 . The DNA molecule according to  claim 1 , wherein the DNA sequence coding for a polypeptide having the enzymatic activity of a fructose-1,6-bisphosphate aldolase has at least about 70% identity with the coding region depicted as SEQ ID NO.1.  
     
     
         8 . The DNA molecule according to  claim 1 , wherein the DNA sequence coding for a polypeptide having the enzymatic activity of a fructose-1,6-bisphosphate aldolase has at least about 80% identity with the coding region depicted as SEQ ID NO.1.  
     
     
         9 . The DNA molecule according to  claim 1 , wherein the DNA sequence coding for the polypeptide having the enzymatic activity of a fructose-1,6-bisphosphate aldolase has the coding region depicted as SEQ ID NO.1, or encodes the same peptide as SEQ ID NO.1 in accordance with the degeneracy of the genetic code.  
     
     
         10 . A transgenic plant cell containing in its genome a recombinant DNA molecule according to any of claims  1 - 9 .  
     
     
         11 . A transgenic plant containing plant cells according to  claim 10 .  
     
     
         12 . The transgenic plant of  claim 11 , wherein the plant exhibits a property selected from the group consisting of increased photosynthesis rates, increased yields, increased growth rates and improved solids uniformity compared with plants that do not contain the recombinant DNA molecule.  
     
     
         13 . The transgenic plant according to  claim 11 , which is a crop plant.  
     
     
         14 . The transgenic plant according to  claim 11 , selected from the group consisting of corn, wheat, rice, tomato, potato, carrots, sweet potato, yams, artichoke, alfalfa, peanut, barley, cotton, soybean, canola, sunflower, sugarbeet, apple, pear, orange, peach, sugarcane, strawberry, raspberry, banana, grape, plantain, tobacco, lettuce, cassava, cruciferous vegetables, forestry species and horticultural species.  
     
     
         15 . The transgenic plant of  claim 11 , wherein the plant is a potato.  
     
     
         16 . A food product derived from the potato of  claim 15 .  
     
     
         17 . The food product of  claim 16 , which is a french fry or a potato chip.  
     
     
         18 . Propagation material derived from the transgenic plant of  claim 11 .  
     
     
         19 . A process for increasing the photosynthesis rate in plants which comprises transforming plant cells with a DNA molecule according to any one of  claims 1  to  9 , and regenerating the transformed cells to produce a transgenic plant.  
     
     
         20 . A process for increasing the yield in plants which comprises transforming plant cells with a DNA molecule according to any one of  claims 1  to  9 , and regenerating the transformed cells to produce a transgenic plant.  
     
     
         21 . A process for increasing the growth rate in plants which comprises transforming plant cells with a DNA molecule according to any one of  claims 1  to  9 , and regenerating the transformed cells to produce a transgenic plant.  
     
     
         22 . A process for improving the solids uniformity in plants which comprises transforming plant cells with a DNA molecule according to any one of  claims 1  to  9 , and regenerating the transformed cells to produce a transgenic plant.  
     
     
         23 . In a method for the processing of potatoes into fries or chips, the improvement comprising, utilizing a potato that overexpresses the fda transgene providing a higher solids uniformity in such potato.