The present invention relates to methods for large-scale production of conjugated fatty acids, especially conjugated linoleic acids in plants. More specifically, the present invention relates to genes identified from
Calendula officinalis coding for a conjugase and its related
enzyme, a .
DELTA.12 desaturase, and utilization of them for large scale production of conjugated linoleic and linolenic acids in plants. The genes encoding a conjugase can introduce two conjugated double bonds at 8 and 10 positions, and a .
DELTA.12 desaturase can introduce a
double bond at 12 position of acyl chains. The constructs containing these genes can be transferred to plants with different substrate profiles, which allows for the production of conjugated linoleic acids (18:2, .
DELTA.8, .DELTA.10) and linolenic acids (18:3, .DELTA.8, .DELTA.10, .DELTA.12) in
plant seeds on a
commercial scale.