Identification of glucosylceramides containing sphingatrienine in maize and rice using ion trap mass spectrometry.

We characterized the glucosylceramide moieties from maize and rice using liquid chromatography-ion trap mass spectrometry. Glucosylceramides containing 4,8-sphingadienine (d18:2) acylated to hydroxy-fatty acids were detected as the predominant molecules both in maize and in rice. In addition, 4-hydroxy-8-sphingenine (t18:1) and sphingatrienine (d18:3) were found in maize and rice glucosylceramides, and in the case of rice, sphingenine (d18:1) was also detected. Glucosylceramides containing d18:3 were acylated to hydroxyl fatty acids (16-24 carbon atoms). Our results indicate the presence of the triene type of sphingoid base in higher plants.