title: Sugars regulate sucrose transporter gene expression in citrus.
abstract: We report the isolation and characterization of two sucrose transporter cDNAs (CitSUT1 and CitSUT2) from citrus. CitSUT1 and CitSUT2 encode putative proteins (CitSUT1 and CitSUT2) of 528 and 607 amino acids, respectively. CitSUT1 and CitSUT2 share high similarities with sucrose transporters isolated from other plants. The expression of CitSUT1 in mature leaf discs is repressed by exogenous sucrose, glucose, mannose, and the glucose analog 2-deoxyglucose but not by another glucose analog 3-O-methylglucose, indicating a hexokinase (HXK)-mediated signaling pathway. CitSUT2 expression is not affected by exogenous sugars. Whereas CitSUT1 expresses strongly in source, sugar exporting organs, CitSUT2 expresses more strongly in sink, sugar importing organs, suggesting different physiological roles for these sucrose transporters.
authors.affiliation: The Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agricultural, Food, and Environmental Quality Sciences, The Hebrew University of Jerusalem, 76100, Rehovot, Israel.
authors.forename: Chun
authors.initials: C
authors.lastname: Yao Li
authors.forename: Jian Xin
authors.initials: JX
authors.lastname: Shi
authors.forename: David
authors.initials: D
authors.lastname: Weiss
authors.forename: Eliezer E
authors.initials: EE
authors.lastname: Goldschmidt
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry; D001692:Biological Transport; D015152:Blotting, Northern; D015139:Blotting, Southern; D050260:Carbohydrate Metabolism; D004247:DNA / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D003847:Deoxyglucose / Q000494:pharmacology; D005638:Fruit; D005947:Glucose / Q000494:pharmacology; D006593:Hexokinase / Q000378:metabolism; D008358:Mannose / Q000494:pharmacology; D026901:Membrane Transport Proteins / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D024301:Plant Bark; D018515:Plant Leaves; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism*; D018517:Plant Roots; D012313:RNA / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013395:Sucrose / Q000378:metabolism* / Q000494:pharmacology; D013997:Time Factors; D014197:Trees
chemical_list: D000596:Amino Acids; D018076:DNA, Complementary; D026901:Membrane Transport Proteins; D010940:Plant Proteins; C078729:sucrose transport protein, plant; D013395:Sucrose; D012313:RNA; D004247:DNA; D003847:Deoxyglucose; D006593:Hexokinase; D005947:Glucose; D008358:Mannose