title: Identification of plant vacuolar transporters mediating phosphate storage.
abstract: Plant vacuoles serve as the primary intracellular compartments for inorganic phosphate (Pi) storage. Passage of Pi across vacuolar membranes plays a critical role in buffering the cytoplasmic Pi level against fluctuations of external Pi and metabolic activities. Here we demonstrate that the SPX-MFS proteins, designated as PHOSPHATE TRANSPORTER 5 family (PHT5), also named Vacuolar Phosphate Transporter (VPT), function as vacuolar Pi transporters. Based on (31)P-magnetic resonance spectroscopy analysis, Arabidopsis pht5;1 loss-of-function mutants accumulate less Pi and exhibit a lower vacuolar-to-cytoplasmic Pi ratio than controls. Conversely, overexpression of PHT5 leads to massive Pi sequestration into vacuoles and altered regulation of Pi starvation-responsive genes. Furthermore, we show that heterologous expression of the rice homologue OsSPX-MFS1 mediates Pi influx to yeast vacuoles. Our findings show that a group of Pi transporters in vacuolar membranes regulate cytoplasmic Pi homeostasis and are required for fitness and plant growth.
authors.affiliation: Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Academia Road, Section 2, Taipei 11529, Taiwan.
authors.forename: Tzu-Yin
authors.initials: TY
authors.lastname: Liu
authors.affiliation: Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Academia Road, Section 2, Taipei 11529, Taiwan.|Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, Academia Sinica, Taipei 11529, Taiwan.|Graduate Institute of Biotechnology, National Chung-Hsing University, Taichung 40243, Taiwan.
authors.forename: Teng-Kuei
authors.initials: TK
authors.lastname: Huang
authors.affiliation: Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Academia Road, Section 2, Taipei 11529, Taiwan.
authors.forename: Shu-Yi
authors.initials: SY
authors.lastname: Yang
authors.affiliation: Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Academia Road, Section 2, Taipei 11529, Taiwan.
authors.forename: Yu-Ting
authors.initials: YT
authors.lastname: Hong
authors.affiliation: Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan.
authors.forename: Sheng-Min
authors.initials: SM
authors.lastname: Huang
authors.affiliation: Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan.
authors.forename: Fu-Nien
authors.initials: FN
authors.lastname: Wang
authors.affiliation: Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Academia Road, Section 2, Taipei 11529, Taiwan.
authors.forename: Su-Fen
authors.initials: SF
authors.lastname: Chiang
authors.affiliation: Graduate Institute of Applied Physics, National Chengchi University, Taipei 11605, Taiwan.
authors.forename: Shang-Yueh
authors.initials: SY
authors.lastname: Tsai
authors.affiliation: Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Academia Road, Section 2, Taipei 11529, Taiwan.
authors.forename: Wen-Chien
authors.initials: WC
authors.lastname: Lu
authors.affiliation: Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Academia Road, Section 2, Taipei 11529, Taiwan.|Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, Academia Sinica, Taipei 11529, Taiwan.|Biotechnology Center, National Chung-Hsing University, Taichung 40243, Taiwan.
authors.forename: Tzyy-Jen
authors.initials: TJ
authors.lastname: Chiou
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D001692:Biological Transport / Q000235:genetics; D006706:Homeostasis; D009682:Magnetic Resonance Spectroscopy; D012275:Oryza / Q000235:genetics; D028061:Phosphate Transport Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D010710:Phosphates / Q000378:metabolism*; D014617:Vacuoles / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D028061:Phosphate Transport Proteins; D010710:Phosphates