Positioning of the SCRAMBLED receptor requires UDP-Glc:sterol glucosyltransferase 80B1 in Arabidopsis roots.

The biological function of sterol glucosides (SGs), the most abundant sterol derivatives in higher plants, remains uncertain. In an effort to improve our understanding of these membrane lipids we examined phenotypes exhibited by the roots of Arabidopsis (Arabidopsis thaliana) lines carrying insertions in the UDP-Glc:sterol glucosyltransferase genes, UGT80A2 and UGT80B1. We show that although ugt80A2 mutants exhibit significantly lower levels of total SGs they are morphologically indistinguishable from wild-type plants.

Functional diversification of two UGT80 enzymes required for steryl glucoside synthesis in Arabidopsis.

Steryl glucosides (SG) are abundant steroid conjugates in plant membranes. Beyond structural roles in lipid bilayers, functions in sugar transport, storage, and/or signalling are predicted. UDP-glucose:sterol glucosyltransferase 80A2 (UGT80A2) and UGT80B1, which share similarity to fungal counterparts, are implicated in SG synthesis in Arabidopsis thaliana.

Steryl glucoside and acyl steryl glucoside analysis of Arabidopsis seeds by electrospray ionization tandem mass spectrometry.

Establishment of sensitive methods for the detection of cellular sterols and their derivatives is a critical step in developing comprehensive lipidomics technology. We demonstrate that electrospray ionization tandem (triple quadrupole) mass spectrometry (ESI-MS/MS) is an efficient method for monitoring steryl glucosides (SG) and acyl steryl glucosides (ASG). Comparison of analysis of SG and ASG by ESI-MS/MS with analysis by gas chromatography with flame ionization detection (GC-FID) shows that the two methods yield similar molar compositions.