Modification of fatty acid metabolism in plants

Abstract

Methods and systems to modify fatty acid biosynthesis and oxidation in plants to make new polymers are provided. Two enzymes are essential: a hydratase such as D-specific enoyl-CoA hydratase, for example, the hydratase obtained from Aeromonas caviae , and a β-oxidation enzyme system. Some plants have a β-oxidation enzyme system which is sufficient to modify polymer synthesis when the plants are engineered to express the hydratase. Examples demonstrate production of polymer by expression of these enzymes in transgenic plants. Examples also demonstrate that modifications in fatty acid biosynthesis can be used to alter plant phenotypes, decreasing or eliminating seed production and increasing green plant biomass, as well as producing polyhydroxyalkanoates.

We claim:  
     
         1 . A method for manipulating the metabolism of a plant, comprising expressing heterologous genes encoding fatty acid oxidation enzymes in the cytosol or plastids other than the peroxisomes, glyoxisomes or mitochondria, of the plant.  
     
     
         2 . The method of  claim 1  wherein the fatty acid β-oxidation enzymes are expressed from genes from selected from the group consisting of bacterial, yeast, fungal, plant, and mammalian genes.  
     
     
         3 . The method of  claim 2  wherein the fatty acid oxidation enzymes are expressed from genes from bacteria selected from the group consisting of Escherichia, Pseudomonas, Alcaligenes, and Coryneform.  
     
     
         4 . The method  claim 3  wherein the genes are  Pseudomonas putida  faoAB.  
     
     
         5 . The method of  claim 1  further comprising 
 expressing genes encoding enzymes selected from the group consisting of polyhydroxyalkanoate synthases, acetoacetyl-CoA reductases, β-ketoacyl-CoA thiolases, and enoyl-CoA hydratases.  
 
     
     
         6 . A DNA construct for use in a method of manipulating the metabolism of a plant cell comprising, in phase, 
 (a) a promoter region functional in a plant;    (b) a structural DNA sequence encoding at least one fatty acid oxidation enzyme activity; and    (c) a 3′ nontranslated region of a gene naturally expressed in a plant, wherein the nontranslated region encodes a signal sequence for polyadenylation of mRNA.    
     
     
         7 . The DNA construct of  claim 6  wherein the promoter is a seed specific promoter.  
     
     
         8 . The DNA construct of  claim 7  wherein the seed specific promoter is selected from the group consisting of napin promoter, phaseolin promoter, oleosin promoter, 2S albumin promoter, zein promoter, β-conglycinin promoter, acyl-carrier protein promoter, and fatty acid desaturase promoter.  
     
     
         9 . The DNA construct of  claim 6  wherein the promoter is a constitutive promoter.  
     
     
         10 . The DNA construct of  claim 6  wherein the promoter is selected from the group consisting of CaMV 35S promoter, enhanced CaMV 35S promoter, and ubiquitin promoter.  
     
     
         11 . A method for enhancing the biological production of polyhydroxyalkanoates in a transgenic plant, comprising expressing genes encoding heterologous fatty acid oxidation enzymes in cytosol or plastids other than the peroxisomes, glyoxisomes or mitochondria, of the plant.  
     
     
         12 . The method of  claim 11  wherein the transgenic plant is selected from the group consisting of Brassica, maize, soybean, cottonseed, sunflower, palm, coconut, safflower, peanut, mustards, flax, tobacco, and alfalfa.  
     
     
         13 . A transgenic plant or part thereof comprising heterologous genes encoding fatty acid oxidation enzymes in cytosol or plastids other than the peroxisomes, glyoxisomes or mitochondria of the plant.  
     
     
         14 . The plant or part thereof of  claim 13  wherein the fatty acid β-oxidation enzymes are expressed from genes selected from the group consisting of bacterial, yeast, fungal, plant, and mammalian.  
     
     
         15 . The plant or part thereof of  claim 14  wherein the fatty acid oxidation enzymes are expressed from genes from bacteria selected from the group consisting of Escherichia, Pseudomonas, Alcaligenes, and Coryneform.  
     
     
         16 . The plant or part thereof of  claim 15  wherein the genes are  Pseudomonas putida  faoAB.  
     
     
         17 . The plant or part thereof of  claim 13  further comprising genes encoding enzymes selected from the group consisting of polyhydroxyalkanoate synthases, acetoacetyl-CoA reductases, β-ketoacyl-CoA thiolases, and enoyl-CoA hydratases.  
     
     
         18 . The plant or part thereof of  claim 13  wherein the plant is selected from the group consisting of Brassica, maize, soybean, cottonseed, sunflower, palm, coconut, safflower, peanut, mustards, flax, tobacco, and alfalfa.  
     
     
         19 . The plant or part thereof of  claim 13  comprising a DNA construct comprising, in phase, 
 (a) a promoter region functional in a plant;  
 (b) a structural DNA sequence encoding at least one fatty acid oxidation enzyme activity; and  
 (c) a 3′ nontranslated region of a gene naturally expressed in a plant, wherein the nontranslated region encodes a signal sequence for polyadenylation of mRNA.  
 
     
     
         20 . The plant or part thereof of  claim 19  wherein the promoter is a seed specific promoter.  
     
     
         21 . The plant or part thereof of  claim 20  wherein the seed specific promoter is selected from the group consisting of napin promoter, phaseolin promoter, oleosin promoter, 2S albumin promoter, zein promoter, β-conglycinin promoter, acyl-carrier protein promoter, and fatty acid desaturase promoter.  
     
     
         22 . The plant or part thereof of  claim 19  wherein the promoter is a constitutive promoter.  
     
     
         23 . The plant or part thereof of  claim 19  wherein the promoter is selected from the group consisting of CaMV 35S promoter, enhanced CaMV 35S promoter, and ubiquitin promoter.  
     
     
         24 . A method of preventing or suppressing seed production in a plant, comprising 
 expressing heterologous genes encoding fatty acid oxidation enzymes in cytosol or plastids other than the peroxisomes, glyoxisomes or mitochondria, of the plant.