title: Rice SPX-Major Facility Superfamily3, a Vacuolar Phosphate Efflux Transporter, Is Involved in Maintaining Phosphate Homeostasis in Rice.
abstract: To maintain a stable cytosol phosphate (Pi) concentration, plant cells store Pi in their vacuoles. When the Pi concentration in the cytosol decreases, Pi is exported from the vacuole into the cytosol. This export is mediated by Pi transporters on the tonoplast. In this study, we demonstrate that SYG1, PHO81, and XPR1 (SPX)-Major Facility Superfamily (MFS) proteins have a similar structure with yeast (Saccharomyces cerevisiae) low-affinity Pi transporters Phosphatase87 (PHO87), PHO90, and PHO91. OsSPX-MFS1, OsSPX-MFS2, and OsSPX-MFS3 all localized on the tonoplast of rice (Oryza sativa) protoplasts, even in the absence of the SPX domain. At high external Pi concentration, OsSPX-MFS3 could partially complement the yeast mutant strain EY917 under pH 5.5, which lacks all five Pi transporters present in yeast. In oocytes, OsSPX-MFS3 was shown to facilitate Pi influx or efflux depending on the external pH and Pi concentrations. In contrast to tonoplast localization in plants cells, OsSPX-MFS3 was localized to the plasma membrane when expressed in both yeast and oocytes. Overexpression of OsSPX-MFS3 results in decreased Pi concentration in the vacuole of rice tissues. We conclude that OsSPX-MFS3 is a low-affinity Pi transporter that mediates Pi efflux from the vacuole into cytosol and is coupled to proton movement.
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China (C.W., W.Y., Y.Y., S.W., Y.L., H.S.);Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Plant Science, School of Agriculture Food and Wine, University of Adelaide, Glen Osmond, South Australia 5064, Australia (C.W., S.D.T.);Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, Western Australia 6009, Australia (D.S.); andDepartment of Animal, Plant, and Soil Science, Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Melbourne, Victoria 3086, Australia (J.W.).
authors.forename: Chuang
authors.identifier: http://orcid.org/0000-0002-7663-7433
authors.initials: C
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China (C.W., W.Y., Y.Y., S.W., Y.L., H.S.);Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Plant Science, School of Agriculture Food and Wine, University of Adelaide, Glen Osmond, South Australia 5064, Australia (C.W., S.D.T.);Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, Western Australia 6009, Australia (D.S.); andDepartment of Animal, Plant, and Soil Science, Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Melbourne, Victoria 3086, Australia (J.W.).
authors.forename: Wenhao
authors.identifier: http://orcid.org/0000-0003-0587-8958
authors.initials: W
authors.lastname: Yue
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China (C.W., W.Y., Y.Y., S.W., Y.L., H.S.);Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Plant Science, School of Agriculture Food and Wine, University of Adelaide, Glen Osmond, South Australia 5064, Australia (C.W., S.D.T.);Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, Western Australia 6009, Australia (D.S.); andDepartment of Animal, Plant, and Soil Science, Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Melbourne, Victoria 3086, Australia (J.W.).
authors.forename: Yinghui
authors.initials: Y
authors.lastname: Ying
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China (C.W., W.Y., Y.Y., S.W., Y.L., H.S.);Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Plant Science, School of Agriculture Food and Wine, University of Adelaide, Glen Osmond, South Australia 5064, Australia (C.W., S.D.T.);Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, Western Australia 6009, Australia (D.S.); andDepartment of Animal, Plant, and Soil Science, Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Melbourne, Victoria 3086, Australia (J.W.).
authors.forename: Shoudong
authors.initials: S
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China (C.W., W.Y., Y.Y., S.W., Y.L., H.S.);Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Plant Science, School of Agriculture Food and Wine, University of Adelaide, Glen Osmond, South Australia 5064, Australia (C.W., S.D.T.);Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, Western Australia 6009, Australia (D.S.); andDepartment of Animal, Plant, and Soil Science, Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Melbourne, Victoria 3086, Australia (J.W.).
authors.forename: David
authors.initials: D
authors.lastname: Secco
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China (C.W., W.Y., Y.Y., S.W., Y.L., H.S.);Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Plant Science, School of Agriculture Food and Wine, University of Adelaide, Glen Osmond, South Australia 5064, Australia (C.W., S.D.T.);Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, Western Australia 6009, Australia (D.S.); andDepartment of Animal, Plant, and Soil Science, Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Melbourne, Victoria 3086, Australia (J.W.).
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China (C.W., W.Y., Y.Y., S.W., Y.L., H.S.);Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Plant Science, School of Agriculture Food and Wine, University of Adelaide, Glen Osmond, South Australia 5064, Australia (C.W., S.D.T.);Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, Western Australia 6009, Australia (D.S.); andDepartment of Animal, Plant, and Soil Science, Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Melbourne, Victoria 3086, Australia (J.W.).
authors.forename: James
authors.initials: J
authors.lastname: Whelan
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China (C.W., W.Y., Y.Y., S.W., Y.L., H.S.);Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Plant Science, School of Agriculture Food and Wine, University of Adelaide, Glen Osmond, South Australia 5064, Australia (C.W., S.D.T.);Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, Western Australia 6009, Australia (D.S.); andDepartment of Animal, Plant, and Soil Science, Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Melbourne, Victoria 3086, Australia (J.W.).
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Tyerman
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China (C.W., W.Y., Y.Y., S.W., Y.L., H.S.);Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Plant Science, School of Agriculture Food and Wine, University of Adelaide, Glen Osmond, South Australia 5064, Australia (C.W., S.D.T.);Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, Western Australia 6009, Australia (D.S.); andDepartment of Animal, Plant, and Soil Science, Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Melbourne, Victoria 3086, Australia (J.W.) huixia@zju.edu.cn.
authors.forename: Huixia
authors.initials: H
authors.lastname: Shou
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D005260:Female; D020869:Gene Expression Profiling / Q000379:methods; D018506:Gene Expression Regulation, Plant; D006706:Homeostasis; D006863:Hydrogen-Ion Concentration; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D009865:Oocytes / Q000378:metabolism; D012275:Oryza / Q000235:genetics / Q000378:metabolism*; D028061:Phosphate Transport Proteins / Q000235:genetics / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011523:Protoplasts / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D014617:Vacuoles / Q000378:metabolism; D014982:Xenopus laevis
chemical_list: D028061:Phosphate Transport Proteins; D010710:Phosphates; D010940:Plant Proteins