The invention relates generally to methods and compositions concerning fungal desaturase enzymes that modulate the number and location of double bonds in long chain poly-unsaturated fatty acids (LC-PUFA's). In Particular, the invention relates to methods and compositions for improving omega-3 fatty acid profiles in plant products and parts using desaturase enzymes and nucleic acids encoding for such enzymes. In particular embodiments, the desaturase enzymes are fungal -15 desaturases. Also provided are improved canola oil compositions having SDA and maintaining beneficial oleic acid content.