Modification of plant lipids containing pufas

Abstract

The present invention generally is concerned with the modification of plant lipids containing PUFAs. In this context, the invention is particularly concerned with plants and plant materials for such modifications, wherein the plants preferably are oilseed plants. Regarding plant parts, the invention is particularly concerned with seeds of such plants and preferably seeds of oilseed plants. The invention is also concerned with plant positions obtainable or obtained by the modification method of the invention, and with full stuff of feedstuff comprising such liquid compositions.

1 . A method of producing a  Brassica napus  plant lipid composition, the method comprising:
 a) growing a  Brassica napus  plant comprising eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and arachidonic acid (ARA), wherein the  Brassica napus  plant comprises a Delta-5 elongase gene under the control of a promoter such that expression of the Delta-5 elongase gene is maintained or increased in late stage seed development, wherein late stage seed development starts after 30 days after flowering;   b) detecting the peak of ARA content in developing seeds;   c) delaying harvesting of the seeds until the content of ARA has decreased and the content of EPA and/or DHA has increased and then harvesting the seeds; and   d) extracting the lipid composition from the seeds to obtain the lipid composition.   
     
     
         2 . The method of  claim 1 , wherein, in the lipid composition:
 a) the content of EPA is at least 5% higher than of ARA, and/or   b) the sum of contents of EPA+DHA is at least 7% higher than ARA and/or   c) the content of ARA is less than 4% and the content of EPA is more than 7% and the content of DHA is more than 2%.   
     
     
         3 . The method of  claim 1 , wherein harvesting is delayed until the content of ARA decreases at least 0.5% by weight of total lipids. 
     
     
         4 . The method of  claim 3 , wherein harvesting is delayed until the content of EPA increases at least 1.0% by weight of total lipids. 
     
     
         5 . The method of  claim 1 , wherein late stage seed development starts after 35 days after flowering. 
     
     
         6 . The method of  claim 1 , wherein late stage seed development starts after 38 days after flowering. 
     
     
         7 . The method of  claim 1 , wherein late stage seed development starts after 40 days after flowering. 
     
     
         8 . The method of  claim 1 , wherein late stage seed development starts after 42 days after flowering. 
     
     
         9 . The method of  claim 1 , wherein, in the lipid composition, the content of EPA is at least 5% higher than of ARA. 
     
     
         10 . The method of  claim 1 , wherein, in the lipid composition, the sum of contents of EPA+DHA is at least 7% higher than ARA. 
     
     
         11 . The method of  claim 1 , wherein, in the lipid composition, the content of ARA is less than 4% and the content of EPA is more than 7% and the content of DHA is more than 2%. 
     
     
         12 . The method of  claim 1 , wherein the Delta-5 elongase gene is under the control of a FAE promoter.