Delta-15 desaturase genes suitable for increasing levels of omega-3 fatty acids

Abstract

The present invention relates to fungal Δ-15 fatty acid desaturases that are able to catalyze the conversion of linoleic acid (18:2, LA) to alpha-linolenic acid (18:3, ALA). Nucleic acid sequences encoding the desaturases, nucleic acid sequences which hybridize thereto, DNA constructs comprising the desaturase genes, and recombinant host plants and microorganisms expressing increased levels of the desaturases are described. Methods of increasing production of specific omega-3 and omega-6 fatty acids by over-expression of the Δ-15 fatty acid desaturases are also described herein.

1 - 47 . (canceled) 
     
     
         48 . Oil obtained from the seeds of an oilseed plant, comprising a recombinant construct for altering the total fatty acid profile of mature seeds of an oilseed plant to produce an oil having an omega 3 to omega 6 ratio greater than 0.4, said construct comprising an isolated nucleic acid fragment selected from the group consisting of:
 (a) an isolated nucleic acid fragment encoding all or part of the amino acid sequence as set forth in SEQ ID NO:2;   (b) an isolated nucleic acid fragment that hybridizes with (a) when washed with 0.1×SSC, 0.1% SDS, 65° C.;   (c) an isolated nucleic acid fragment encoding an amino acid sequence having at least 46.2% sequence identity with the amino acid sequences set forth in SEQ ID NOs:2, 6, 10, 14, 18 based on the Clustal V method of alignment; or   (d) an isolated nucleic acid fragment that is completely complementary to (a), (b), or (c)   
       wherein said isolated nucleic acid fragment is operably linked to at least one regulatory sequence. 
     
     
         49 . By-products obtained from the processing of the oil of  claim 48 . 
     
     
         50 . The By-products of  claim 49  wherein said By-product is lecithin. 
     
     
         51 . Use of the oil of  claim 50  in food, animal feed or an industrial application. 
     
     
         52 . Use of the By-product of  claim 49  or  50  in food or animal feed. 
     
     
         53 . Oil obtained from the seeds of an oilseed plant obtained by a method for increasing the ratio of omega-3 fatty acids to omega-6 fatty acids in an oilseed plant comprising:
 i) transforming an oilseed plant cell of with a recombinant construct for altering the total fatty acid profile of mature seeds of an oilseed plant to produce an oil having an omega 3 to omega 6 ratio greater than 0.4, said construct comprising an isolated nucleic acid fragment selected from the group consisting of:
 (a) an isolated nucleic acid fragment encoding all or part of the amino acid sequence as set forth in SEQ ID NO:2; 
 (b) an isolated nucleic acid fragment that hybridizes with (a) when washed with 0.1×SSC, 0.1% SDS, 65° C.; 
 (c) an isolated nucleic acid fragment encoding an amino acid sequence having at least 46.2% sequence identity with the amino acid sequences set forth in SEQ ID NOs:2, 6, 10, 14, 18 based on the Clustal V method of alignment; or 
 (d) an isolated nucleic acid fragment that is completely complementary to (a), (b), or (c) 
   
       wherein said isolated nucleic acid fragment is operably linked to at least one regulatory sequence.
 ii) regenerating an oilseed plant from the transformed plant cell of step (i); 
 iii) selecting those transformed plants having an increased ratio of omega-3 fatty acids to omega-6 fatty acids compared to the ratio of omega-3 fatty acids to omega-6 fatty acids in an untransformed plant. 
 
     
     
         54 . By-products obtained from the processing of the oil of  claim 53 . 
     
     
         55 . The By-products of  claim 54  wherein said By-product is lecithin. 
     
     
         56 . Use of the oil of  claim 53  in food, animal feed or an industrial application. 
     
     
         57 . Use of the By-product of  claim 54  or  55  in food or animal feed. 
     
     
         58 . Oil obtained from an oilseed plant, obtained by a method for producing alpha-linolenic acid in seed of an oilseed plant wherein the alpha-linolenic acid content of the oil in the seed is at least 25% of the total fatty acid content of the seed oil, said method comprising:
 i) transforming an oilseed plant cell with a recombinant construct for altering the total fatty acid profile of mature seeds of an oilseed plant to produce an oil having an omega 3 to omega 6 ratio greater than 0.4, said construct comprising an isolated nucleic acid fragment selected from the group consisting of:
 (a) an isolated nucleic acid fragment encoding all or part of the amino acid sequence as set forth in SEQ ID NO:2; 
 (b) an isolated nucleic acid fragment that hybridizes with (a) when washed with 0.1×SSC, 0.1% SDS, 65° C.; 
 (c) an isolated nucleic acid fragment encoding an amino acid sequence having at least 46.2% sequence identity with the amino acid sequences set forth in SEQ ID NOs:2, 6, 10, 14, 18 based on the Clustal V method of alignment; or 
 (d) an isolated nucleic acid fragment that is completely complementary to (a), (b), or (c) 
   
       wherein said isolated nucleic acid fragment is operably linked to at least one regulatory sequence:
 ii) regenerating an oilseed plant from the transformed plant cell of step (i); 
 iii) selecting those transformed plants having at least 25% alpha-linolenic acid of the total fatty acid content of the seed oil. 
 
     
     
         59 . By-products obtained from the processing of the oil of  claim 58 . 
     
     
         60 . The By-products of  claim 59  wherein said By-product is lecithin. 
     
     
         61 . Use of the oil of  claim 58  in food, animal feed or an industrial application. 
     
     
         62 . Use of the By-product of  claim 59  or  60  in food or animal feed. 
     
     
         63 . Oil obtained from the seeds of an oilseed plant comprising in its genome a recombinant construct for altering the total fatty acid profile of mature seeds of an oilseed plant to produce an oil having an omega 3 to omega 6 ratio greater than 2, wherein said oil has an eicosapentaenoic acid content greater than 2%, said construct comprising an isolated nucleic acid fragment selected from the group consisting of:
 (a) an isolated nucleic acid fragment encoding all or part of the amino acid sequence as set forth in SEQ ID NO:2;   (b) an isolated nucleic acid fragment that hybridizes with (a) when washed with 0.1×SSC, 0.1% SDS, 65° C.;   (c) an isolated nucleic acid fragment encoding an amino acid sequence having at least 46.2% sequence identity with the amino acid sequences set forth in SEQ ID NOs:2, 6, 10, 14, 18 based on the Clustal V method of alignment; or   (d) an isolated nucleic acid fragment that is completely complementary to (a), (b), or (c)   wherein said isolated nucleic acid fragment is operably linked to at least one regulatory sequence.   
     
     
         64 . By-products obtained from the processing of the oil of  claim 63 . 
     
     
         65 . The By-products of  claim 64  wherein said By-product is lecithin. 
     
     
         66 . Use of the oil of  claim 63  in food, animal feed or an industrial application. 
     
     
         67 . Use of the By-product of  claim 64  or  65  in food or animal feed. 
     
     
         68 . Oil obtained from the seeds of an oilseed plant made by a method comprising producing eicosapentaenoic acid in seed of an oilseed plant to produce an oil having an omega 3 to omega 6 ratio greater than 2, wherein said oil has an eicosapentaenoic acid content greater than 2% of the total fatty acid content of the seed oil, said method comprising:
 i) transforming an oilseed plant cell of with a recombinant construct for altering the total fatty acid profile of mature seeds of an oilseed plant to produce an oil having an omega 3 to omega 6 ratio greater than 2, wherein said oil has an eicosapentaenoic acid content greater than 2%, said construct comprising an isolated nucleic acid fragment selected from the group consisting of:
 (a) an isolated nucleic acid fragment encoding all or part of the amino acid sequence as set forth in SEQ ID NO:2; 
 (b) an isolated nucleic acid fragment that hybridizes with (a) when washed with 0.1×SSC, 0.1% SDS, 65° C.; 
 (c) an isolated nucleic acid fragment encoding an amino acid sequence having at least 46.2% sequence identity with the amino acid sequences set forth in SEQ ID NOs:2, 6, 10, 14, 18 based on the Clustal V method of alignment; or 
 (d) an isolated nucleic acid fragment that is completely complementary to (a), (b), or (c) 
   wherein said isolated nucleic acid fragment is operably linked to at least one regulatory sequence:
 ii) regenerating an oilseed plant from the transformed plant cell of step (i); 
 iii) selecting those transformed plants having at least 2% eicosapentaenoic acid of the total fatty acid content of the seed oil. 
   
     
     
         69 . By-products obtained from the processing of the oil of  claim 68 . 
     
     
         70 . The By-products of  claim 69  wherein said By-product is lecithin. 
     
     
         71 . Use of the oil of  claim 68  in food, animal feed or an industrial application. 
     
     
         72 . Use of the By-product of  claim 69  or  70  in food or animal feed.