Four near-isogenic B. napus varieties, with decreasing amounts of erucic acid and glucosinolates reflecting the actual breeding process, were used to characterize the proteins affected during this process. Following improvement of 2-DE conditions, proteins differentially accumulated were identified by mass spectrometry analysis. Accumulation of cruciferins was found to be only slightly affected, whereas significant quantitative differences were mainly found for proteins involved in defense system and carbohydrate metabolism.