title: A cascade of sequentially expressed sucrose transporters in the seed coat and endosperm provides nutrition for the Arabidopsis embryo.
abstract: Developing plant embryos depend on nutrition from maternal tissues via the seed coat and endosperm, but the mechanisms that supply nutrients to plant embryos have remained elusive. Sucrose, the major transport form of carbohydrate in plants, is delivered via the phloem to the maternal seed coat and then secreted from the seed coat to feed the embryo. Here, we show that seed filling in Arabidopsis thaliana requires the three sucrose transporters SWEET11, 12, and 15. SWEET11, 12, and 15 exhibit specific spatiotemporal expression patterns in developing seeds, but only a sweet11;12;15 triple mutant showed severe seed defects, which include retarded embryo development, reduced seed weight, and reduced starch and lipid content, causing a "wrinkled" seed phenotype. In sweet11;12;15 triple mutants, starch accumulated in the seed coat but not the embryo, implicating SWEET-mediated sucrose efflux in the transfer of sugars from seed coat to embryo. This cascade of sequentially expressed SWEETs provides the feeding pathway for the plant embryo, an important feature for yield potential.
authors: Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305 lchen@carnegiescience.edu wfrommer@carnegiescience.edu.
authors: Li-Qing
authors: http://orcid.org/0000-0002-0964-5388
authors: LQ
authors: Chen
authors: Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305 Department of Biology, Stanford University, Stanford, California 94305.
authors: I Winnie
authors: IW
authors: Lin
authors: Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305.
authors: Xiao-Qing
authors: XQ
authors: Qu
authors: Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305.
authors: Davide
authors: D
authors: Sosso
authors: Department of Botany, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
authors: Heather E
authors: HE
authors: McFarlane
authors: Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305.
authors: Alejandra
authors: A
authors: Londoño
authors: Department of Botany, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
authors: A Lacey
authors: AL
authors: Samuels
authors: Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305 lchen@carnegiescience.edu wfrommer@carnegiescience.edu.
authors: Wolf B
authors: WB
authors: Frommer
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000187:drug effects / Q000196:embryology* / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport / Q000187:drug effects / Q000235:genetics; D056625:Endosperm / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D009747:Nutritional Physiological Phenomena / Q000187:drug effects; D009865:Oocytes / Q000378:metabolism; D009928:Organ Specificity / Q000187:drug effects / Q000235:genetics; D010641:Phenotype; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D013213:Starch / Q000378:metabolism; D013395:Sucrose / Q000378:metabolism / Q000494:pharmacology; D013997:Time Factors; D014982:Xenopus laevis; D008565:Membrane Proteins
chemical_list: D029681:Arabidopsis Proteins; D026901:Membrane Transport Proteins; D013213:Starch; D013395:Sucrose; C569466:SWEET11 protein, Arabidopsis; C569467:SWEET12 protein, Arabidopsis; C557299:At5g13170 protein, Arabidopsis; D008565:Membrane Proteins