Tomato UDP-Glucose Sterol Glycosyltransferases: A Family of Developmental and Stress Regulated Genes that Encode Cytosolic and Membrane-Associated Forms of the Enzyme.

摘要: Sterol glycosyltransferases (SGTs) catalyze the glycosylation of free hydroxyl group at C-3 position sterols to produce sterol glycosides. Glycosylated and are primarily located in cell membranes where combination with other membrane-bound lipids play a key role modulating their properties functioning. In contrast most plant species, those genus Solanum contain very high levels glycosylated sterols, which case tomato may account for more than 85% total content. this study, we report identification functional characterization four members (Solanum lycopersicum cv. Micro-Tom) SGT gene family. Expression recombinant SlSGT proteins E. coli cells N. benthamiana leaves demonstrated ability enzymes glycosylate different species including cholesterol, brassicasterol, campesterol, stigmasterol, β-sitosterol, is consistent occurrence primary structure putative steroid-binding domain found steroid UDP-glucuronosyltransferases UDP-sugar binding characteristic superfamily nucleoside diphosphosugar glycosyltransferases. Subcellular localization studies based on fluorescence recovery after photobleaching fractionation analyses revealed that SGTs, like Arabidopsis SGTs UGT80A2 UGT80B1, localize into cytosol PM, although there clear differences relative distribution between these two fractions. The genes have specialized but still largely overlapping expression patterns organs plants throughout stages fruit development ripening. Moreover, they differentially regulated response biotic abiotic stress conditions. SlSGT4 increases markedly osmotic, salt, cold stress, as well upon treatment abscisic acid methyl jasmonate. Stress-induced SlSGT2 parallels SlSGT4. On contrary, SlSGT1 SlSGT3 remains almost unaltered under tested Overall, study contributes broaden current knowledge provides support view not completely redundant biological functions involved mediating developmental responses.