Depressed expression of FAE1 and FAD2 genes modifies fatty acid profiles and storage compounds accumulation in Brassica napus seeds

•The growth and development are not affected in BnFAD2 and BnFAE1 transgenic lines.•BnFAD2 and BnFAE1 transgenic seeds show increased oleic acid and decreased erucic acid levels.•Seed-specific depression of BnFAD2 and BnFAE1 leads to the slight decrease of oil contents in oilseeds.•Protein contents in BnFAD2 and BnFAE1 transgenic seeds are increased to some extents.