title: Mechanisms of ammonium transport, accumulation, and retention in ooyctes and yeast cells expressing Arabidopsis AtAMT1;1.
abstract: Ammonium is a primary source of N for plants, so knowing how it is transported, stored, and assimilated in plant cells is important for rational approaches to optimise N-use in agriculture. Electrophysiological studies of Arabidopsis AtAMT1;1 expressed in oocytes revealed passive, Deltapsi-driven transport of NH(4)(+) through this protein. Expression of AtAMT1;1 in a novel yeast mutant defective in endogenous ammonium transport and vacuolar acidification supported the above mechanism for AtAMT1;1 and revealed a central role for acid vacuoles in storage and retention of ammonia in cells. These results highlight the mechanistic differences between plant AMT proteins and related transporters in bacteria and animal cells, and suggest novel strategies to enhance nitrogen use efficiency in agriculture.
authors.affiliation: Max-Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Golm, Germany.
authors.forename: Craig C
authors.initials: CC
authors.lastname: Wood
authors.forename: Fabien
authors.initials: F
authors.lastname: Porée
authors.forename: Ingo
authors.initials: I
authors.lastname: Dreyer
authors.forename: Gabriele J
authors.initials: GJ
authors.lastname: Koehler
authors.forename: Michael K
authors.initials: MK
authors.lastname: Udvardi
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000235:genetics; D027682:Cation Transport Proteins / Q000235:genetics* / Q000378:metabolism*; D015870:Gene Expression; D017136:Ion Transport; D008954:Models, Biological; D009865:Oocytes / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism*; D000644:Quaternary Ammonium Compounds / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000378:metabolism*; D014617:Vacuoles; D014981:Xenopus
chemical_list: D027682:Cation Transport Proteins; D010940:Plant Proteins; D000644:Quaternary Ammonium Compounds; C088952:ammonium transporters, plant