Methods for increasing oleic acid content in seeds from transgenic plants containing a mutant delta 12 desaturase

• US 7,109,392 B1
• Filed: 08/22/2000
• Issued: 09/19/2006
• Est. Priority Date: 10/09/1996
• Status: Expired due to Fees

• Current Assignee: Cargill Incorporated
• Original Assignee: Cargill Incorporated
• Inventors: DeBonte, Lorin Roger, Miao, Guo-Hua, Hitz, William Dean, Reiter, Robert Stefan, Broglie, Richard Martin
• Primary Examiner(s): KALLIS, RUSSELL
• Application Number:
  US09/643,579
• Time in Patent Office: 2,219 Days
• Field of Search: 800/278, 800/281, 800/295, 800/298, 800/306, 800/287, 800/312, 800/314, 800/320.1, 435/183, 435/320.1, 536/23.1, 536/23.2, 536/23.6
• US Class Current: 800/281
• CPC Class Codes: C12N 15/8247 involving modified lipid metabolism, e.g. seed oil composition
• CPC Class Codes: C12N 9/0083 Miscellaneous (1.14.99)

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 mutant delta-12 fatty acid desaturase nucleic acid fragments with suitable regulatory sequences may be used to create transgenic plants with altered levels of unsaturated fatty acids.

Claims

1. A method for increasing the oleic acid content in plant seeds, comprising the steps of:

a) introducing a recombinant nucleic acid construct into a plant, said construct comprising at least one seed-specific regulatory sequence operably linked in sense orientation to a full length delta-12 fatty acid desaturase coding sequence, wherein said sequence encodes a delta-12 fatty acid desaturase protein having a substitution of a Lys residue for Asp or Glu in an amino acid region selected from the group consisting of His-Glu-Cys-Gly-His (SEQ ID NO;

53), His-Asp-Cys-Gly-His (SEQ ID NO;

55), and His-Asp-Cys-Ala-His (SEQ ID NO;

54),

b) obtaining progeny from said plant, said progeny producing said seeds having an oleic acid content of from about 72.5% to about 78.6%.

3. The method of claim 1, wherein said substitution is in a His-Glu-Cys-Gly-His (SEQ ID NO:

53) amino acid region.

4. The method of claim 1, wherein said plant is soybean.

5. The method of claim 1, wherein said plant is rapeseed.

6. The method of claim 1, wherein said plant is cotton.

7. The method of claim 1, wherein said plant is corn.

8. The method of claim 1, wherein said plant is safflower.

9. The method of claim 1, wherein said seed-specific regulatory sequence is a bean β

-phaseolin promoter.

10. The method of claim 1, wherein said seed-specific regulatory sequence is an α

subunit of soybean β

-conglycinin promoter.

11. The method of claim 1, wherein said seed-specific regulatory sequence is maize 18 kd oleosin promoter.

12. The method of claim 1, wherein said seed-specific regulatory sequence is maize 15 kd zein promoter.

13. The method of claim 1, wherein said seed-specific regulatory sequence is a Brassica napin promoter.

14. The method of claim 1, wherein said seeds have a linoleic acid content of about 6.4% to about 10.6%.

15. The method of claim 1, wherein said seeds have an α

-linolenic acid content of about 4.5% to about 6.5%.

2. A recombinant nucleic acid construct effective for increasing oleic acid content when expressed in seeds, said construct comprising at least one seed-specific regulatory sequence operably linked in sense orientation to a delta-12 fatty acid desaturase coding sequence encoding a delta-12 fatty acid desaturase gene product having at least one mutation which renders said desaturase gene product non-functional, said mutation being the substitution of a Lys residue for Asp in an amino acid region selected from the group consisting of His-Asp-Cys-Gly-His (SEQ ID NO:

55) and His-Asp-Cys-Ala-His (SEQ ID NO;

54).