Genes For Microsomal Delta-12 Fatty Acid Desaturases And Hydroxylases From Plants

Abstract

The preparation and use of nucleic acid fragments encoding fatty acid desaturase enzymes are described. The invention permits alteration of plant lipid composition. Chimeric genes incorporating such nucleic acid fragments with suitable regulatory sequences may be used to create transgenic plants with altered levels of unsaturated fatty acids.

1 - 27 . (canceled)  
     
     
         28 . An isolated polynucleotide obtained from a plant FAD2 genetic locus, said locus comprising plant genomic DNA having at least 90% sequence identity to any one of the sequences set forth in SEQ ID NOs:1, 3, 5, 7, 9, 11, or 15.  
     
     
         29 . The isolated polynucleotide of  claim 28  comprising a sequence selected from the group consisting of a 5′ non-coding sequence, a 3′ non-coding sequence and an intron sequence.  
     
     
         30 . A chimeric gene comprising the isolated polynucleotide of  claim 29  operably linked, in a sense or antisense orientation, to at least one regulatory sequence.  
     
     
         31 . A plant comprising in its genome the chimeric gene of  claim 30 .  
     
     
         32 . Seed obtained from the plant of  claim 31 .  
     
     
         33 . Oil obtained from the seed of  claim 32 .  
     
     
         34 . A method for producing seed having altered levels of unsaturated fatty acids comprising: 
 a) transforming a plant cell with a chimeric gene comprising the isolated polynucleotide of  claim 29;     b) growing fertile plants from the transformed plant cell of step (a); and    c) screening progeny seeds from the fertile plants of step (b) for altered levels of unsaturated fatty acids.    
     
     
         35 . A seed of a soybean plant wherein the seed has a fatty acid composition comprising an oleic acid content of at least 70% and wherein the soybean plant comprises in its genome a chimeric gene comprising a nucleic acid fragment operably linked to at least one regulatory sequence wherein the nucleic acid fragment is selected from the group consisting of: 
 (a) a nucleic acid fragment encoding a fatty acid desaturase with an amino acid identity of 50% or greater to the polypeptide encoded by any one of the sequences set forth in SEQ ID NOS:1, 3, 5, 7, 9, 11 or 15;    (b) a nucleic acid sequence or a part thereof which is useful in antisense inhibition or sense suppression of endogenous desaturase activity in a transformed plant wherein the nucleic acid has an identity of 90% or greater to any one of the sequences set forth in SEQ ID NOS:1, 3, 5, 7, 9, 11, or 15; or    (c) a nucleic acid sequence or a part thereof which is useful in antisense inhibition or sense suppression of endogenous desaturase activity in a transformed plant wherein the nucleic acid sequence hybridizes to any one of the sequences set forth in SEQ ID NOS:1, 3, 5, 7, 9, 11 or 15, under one of the following sets of conditions: 
 (i) hybridization in 50 mM Tris, pH 7.6, 6×SSC, 5×Denhardt's, 0.5% sodium dodecyl sulfate (SDS), 100 μg/ml denatured calf thymus DNA at 50° C. and wash twice with 2×SSC, 0.5% SDS at room temperature for 15 min each, then wash twice with 0.2×SSC, 0.5% SDS at room temperature for 15 min each and then wash twice with 0.2×SSC, 0.5% SDS at 50° C. for 15 min each;  
 (ii) hybridization in 6×SSPE, 5×Denhardt's solution, 0.5% sodium dodecyl sulfate (SDS), 5% dextran sulfate, 100 μg/ml denatured salmon sperm DNA at 50° C. and wash twice with 2×SSC, 0.5% SDS at room temperature for 15 min each, then wash twice with 0.2×SSC, 0.5% SDS at room temperature for 15 min each and then wash twice with 0.2×SSC, 0.5% SDS at 50° C. for 15 min each;  
 (iii) hybridization in 50% formamide, 5×SSPE, 1% sodium dodecyl sulfate (SDS), 1×Denhardt's Reagent, 100 μg/ml denatured salmon sperm DNA at 42° C. and wash three times with 2×SSPE, 0.2% SDS at 42° C. for 15 min each, then wash twice with 0.2×SSPE, 0.2% SDS at 55° C. for 30 min each; or  
   (d) the isolated polynucleotide of claim  2 .    
     
     
         36 . The seed of  claim 35  wherein the oleic acid content is at least 79%.  
     
     
         37 . A seed of a soybean plant wherein the seed has a fatty acid composition comprising an oleic acid content of at least 75%.  
     
     
         38 . The seed of  claim 37  wherein the oleic acid content is at least 77%.  
     
     
         39 . The seed of  claim 37  wherein the oleic acid content is at least 79%.  
     
     
         40 . The seed of any one of claims  37 ,  38  or  39  wherein the linolenic acid content is no more than 7%.  
     
     
         41 . A seed of a soybean plant wherein the seed has a fatty acid composition comprising an oleic acid content of at least 70% and a linoleic acid content of no more than 11.2%.  
     
     
         42 . The seed of  claim 41  wherein the oleic acid content is at least 79%.  
     
     
         43 . The seed of any one of claims  41  or  42  wherein the linoleic acid content is no more than 9.5%.