title: Steryl glucoside and acyl steryl glucoside analysis of Arabidopsis seeds by electrospray ionization tandem mass spectrometry.
abstract: 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. These data demonstrate that ESI-MS/MS response per molar amount of sterol conjugate is similar among various molecular species of SG and ASG. Application of ESI-MS/MS to seed samples from wild-type Arabidopsis and a mutant deficient in two UDP-glucose:sterol glucosyltransferases, UGT80A2 and UGT80B1, revealed new details on the composition of sitosteryl, campesteryl and stigmasteryl glucosides and ASG. SG were decreased by 86% in the ugt80A2,B1 double mutant, compared to the wild-type, while ASG were reduced 96%. The results indicate that these glucosyltransferases account for much of the accumulation of the sterol conjugates in wild-type Arabidopsis seeds.
authors.affiliation: Division of Biology, 116 Ackert Hall, Kansas State University, Manhattan, KS 66506-4901, USA. kschrick@ksu.edu
authors.forename: Kathrin
authors.initials: K
authors.lastname: Schrick
authors.forename: Sunitha
authors.initials: S
authors.lastname: Shiva
authors.forename: James C
authors.initials: JC
authors.lastname: Arpin
authors.forename: Nicole
authors.initials: N
authors.lastname: Delimont
authors.forename: Giorgis
authors.initials: G
authors.lastname: Isaac
authors.forename: Pamela
authors.initials: P
authors.lastname: Tamura
authors.forename: Ruth
authors.initials: R
authors.lastname: Welti
mesh_terms: D017360:Arabidopsis / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000737:chemistry; D005964:Glucosyltransferases / Q000737:chemistry*; D012639:Seeds / Q000737:chemistry* / Q000201:enzymology; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D013261:Sterols / Q000032:analysis*
chemical_list: D029681:Arabidopsis Proteins; D013261:Sterols; D005964:Glucosyltransferases; C577616:UGT80A2 protein, Arabidopsis; C577617:UGT80B1 protein, Arabidopsis