Plant Fatty Acid Synthases and Use in Improved Methods for Production of Medium-Chain Fatty Acids

Abstract

By this invention, compositions and methods of use related to β-ketoacyl-ACP synthase Of special interest are synthases obtainable from Cuphea species. Amino acid and nucleic acid for synthase protein factors are provided, as well as methods to utilize such sequences in constructs for production of genetically engineered plants having altered fatty acid compositions. Of particular interest is the expression of synthase protein factors in conjunction with expression of plant medium-chain acyl-ACP thioesterases for production of increased levels and/or modified ratios of medium-chain fatty acids in oils of transgenic plant seeds.

1 . A plant seed comprising a coding sequence for a medium-chain thioesterase protein, and a coding sequence for a β-ketoacyl-ACP synthase (KAS) protein, wherein the composition of medium-chain fatty acids produced in said plant seed is modified. 
     
     
         2 . The plant seed according to  claim 1 , wherein said KAS protein is a KAS factor A protein. 
     
     
         3 . The plant seed according to  claim 1 , wherein said KAS protein is a KAS factor B protein. 
     
     
         4 . The plant seed according to  claim 1 , wherein said plant seed composition is modified as compared to the composition of medium-chain fatty acids produced in plant seed expressing said medium-chain thioesterase protein in the absence of expression of said KAS protein. 
     
     
         5 . The plant seed of  claim 1 , wherein said KAS factor protein is from a  Cuphea  species. 
     
     
         6 . The plant seed of  claim 1 , wherein said KAS factor protein comprises a coding sequence as set forth in SEQ ID NO:5. 
     
     
         7 . The plant seed of  claim 1 , wherein said KAS factor protein comprises a coding sequence encoding an amino acid sequence as set forth in SEQ ID NO:6. 
     
     
         8 . The plant seed of  claim 1 , wherein said KAS factor protein comprises a coding sequence encoding an amino acid sequence set forth in residues 125-466 of SEQ ID NO:6. 
     
     
         9 . The plant seed of  claim 1 , wherein said fatty acid composition is enriched for C10 fatty acids. 
     
     
         10 . The plant seed of  claim 1 , wherein said fatty acid composition is enriched for C12 fatty acids. 
     
     
         11 . The plant seed of  claim 1 , wherein said fatty acid composition is enriched for at least one medium chain fatty acid and at least one other medium chain fatty acid is decreased. 
     
     
         12 . The plant seed of  claim 11 , wherein said fatty acid composition has an increased ratio of C10 fatty acids to C8 fatty acids relative to the composition of medium-chain fatty acids produced in plant seed expressing said medium-chain thioesterase protein in the absence of expression of said KAS protein. 
     
     
         13 . The plant seed of  claim 11 , wherein said fatty acid composition has an increased total content of C10 fatty acids and C8 fatty acids relative to the composition of medium-chain fatty acids produced in plant seed expressing said medium-chain thioesterase protein in the absence of expression of said KAS protein. 
     
     
         14 . The plant seed of  claim 1 , wherein said thioesterase protein is selected from the group consisting of  Cuphea hookeriana  FatB2,  Cuphea pulcherrima  FatB1,  Umbellularia californica  FatB1, and  Garcinia mangostana  FatA1. 
     
     
         15 . A plant seed exhibiting a seed oil fatty acid composition comprising a C10 fatty acid to C8 fatty acid ratio as high as 22, wherein said seed comprises comprising a coding sequence for a medium-chain thioesterase protein and a coding sequence for a β-ketoacyl-ACP synthase (KAS) factor. 
     
     
         16 . The plant seed according to  claim 15 , wherein said KAS protein is a KAS factor A protein. 
     
     
         17 . The plant seed according to  claim 15 , wherein said KAS protein is a KAS factor B protein. 
     
     
         18 . The plant seed of  claim 15 , wherein said C10 fatty acid to C8 fatty acid ratio is higher as compared to the C10 fatty acid to C8 fatty acid ratio produced in seeds expressing said plant medium-chain thioesterase protein in the absence of expression of said KAS factor protein. 
     
     
         19 . The plant seed of  claim 15 , wherein said C10 fatty acid to C8 fatty acid ratio is between 7 and 22. 
     
     
         20 . The plant seed of  claim 15 , wherein said C10 fatty acid to C8 fatty acid ratio is between 7 and 16. 
     
     
         21 . The plant seed of  claim 12 , wherein said KAS factor protein is from a  Cuphea  species. 
     
     
         22 . A plant seed exhibiting a seed oil fatty acid composition enriched for at least one medium chain fatty acid and at least one other medium chain fatty acid is decreased, wherein said seed comprises a coding sequence for a medium-chain thioesterase protein and a coding sequence for a β-ketoacyl-ACP synthase (KAS) factor protein. 
     
     
         23 . The plant seed according to  claim 22 , wherein said KAS protein is a KAS factor A protein. 
     
     
         24 . The plant seed according to  claim 22 , wherein said KAS protein is a KAS factor B protein. 
     
     
         25 . The plant seed of  claim 22 , wherein said enriched fatty acid is C12 and said decreased fatty acid is C14. 
     
     
         26 . The plant seed of  claim 22 , wherein said seed oil comprises up to 57 mol % C12:0. 
     
     
         27 . The plant seed of  claim 22 , wherein said seed oil comprises between 34 and 50 weight percent of C12:0. 
     
     
         28 . The plant seed of  claim 22 , wherein said decreased fatty acid is C18:0. 
     
     
         29 . The plant seed of  claim 22 , wherein said C18:0 levels are decreased to approximately 12 mol %. 
     
     
         30 . A seed oil fatty acid composition comprising a modified level of medium-chain fatty acids, wherein said seed oil is derived from a transgenic plant comprising a coding sequence for a medium-chain thioesterase protein and a coding sequence for a β-ketoacyl-ACP synthase (KAS) factor protein. 
     
     
         31 . The seed oil according to  claim 30 , wherein said KAS protein is a KAS factor A protein. 
     
     
         32 . The seed oil according to  claim 30 , wherein said KAS protein is a KAS factor B protein. 
     
     
         33 . The seed oil according to  claim 30 , wherein said seed oil is modified as compared to the composition of medium-chain fatty acids produced in plant seed expressing said medium-chain thioesterase protein in the absence of expression of said KAS protein. 
     
     
         34 . The seed oil according to  claim 30 , wherein said KAS factor protein is from a  Cuphea  species. 
     
     
         35 . The seed oil according to  claim 30  comprising a C10 fatty acid to C8 fatty acid ratio as high as 22. 
     
     
         36 . The seed oil of  claim 35 , wherein said C10 fatty acid to C8 fatty acid ratio is between 7 and 22. 
     
     
         37 . The seed oil of  claim 35 , wherein said C10 fatty acid to C8 fatty acid ratio is between 7 and 16. 
     
     
         38 . The seed oil of  claim 30 , wherein said fatty acid composition is enriched for at least one medium chain fatty acid and at least one other medium chain fatty acid is decreased. 
     
     
         39 . The seed oil of  claim 38 , wherein said enriched fatty acid is C12 and said decreased fatty acid is C14. 
     
     
         40 . The seed oil of  claim 38 , wherein said seed oil comprises up to 57 mol % C12:0. 
     
     
         41 . The seed oil of  claim 38 , wherein said seed oil comprises between 34 and 50 weight percent of C12:0. 
     
     
         42 . The seed oil of  claim 38 , wherein said decreased fatty acid is C18:0. 
     
     
         43 . The seed oil of  claim 38 , wherein said C18:0 levels are decreased to approximately 12 mol %.