title: Amino acid transporter mutants of Arabidopsis provides evidence that a non-mycorrhizal plant acquires organic nitrogen from agricultural soil.
abstract: Although organic nitrogen (N) compounds are ubiquitous in soil solutions, their potential role in plant N nutrition has been questioned. We performed a range of experiments on Arabidopsis thaliana genetically modified to enhance or reduce root uptake of amino acids. Plants lacking expression of the Lysine Histidine Transporter 1 (LHT1) displayed significantly lower contents of13C and15N label and of U-13C5,15N2L-glutamine, as determined by liquid chromatography-mass spectrometry when growing in pots and supplied with dually labelled L-glutamine compared to wild type plants and LHT1-overexpressing plants. Slopes of regressions between accumulation of13C-labelled carbon and15N-labelled N were higher for LHT1-overexpressing plants than wild type plants, while plants lacking expression of LHT1 did not display a significant regression between the two isotopes. Uptake of labelled organic N from soil tallied with that of labelled ammonium for wild type plants and LHT1-overexpressing plants but was significantly lower for plants lacking expression of LHT1. When grown on agricultural soil plants lacking expression of LHT1 had the lowest, and plants overexpressing LHT1 the highest C/N ratios and natural δ15N abundance suggesting their dependence on different N pools. Our data show that LHT1 expression is crucial for plant uptake of organic N from soil.
authors.affiliation: Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83, Umeå, Sweden.
authors.forename: Ulrika
authors.initials: U
authors.lastname: Ganeteg
authors.affiliation: Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83, Umeå, Sweden.
authors.forename: Iftikhar
authors.initials: I
authors.lastname: Ahmad
authors.affiliation: Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83, Umeå, Sweden.
authors.forename: Sandra
authors.initials: S
authors.lastname: Jämtgård
authors.affiliation: Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83, Umeå, Sweden.
authors.forename: Camila
authors.initials: C
authors.lastname: Aguetoni-Cambui
authors.affiliation: Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83, Umeå, Sweden.|University of Vienna, Department of Geography and Regional Research, Vienna, AT-1090, Austria.
authors.forename: Erich
authors.initials: E
authors.lastname: Inselsbacher
authors.affiliation: Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83, Umeå, Sweden.
authors.forename: Henrik
authors.initials: H
authors.lastname: Svennerstam
authors.affiliation: School of Agriculture and Food Sciences, The University of Queensland, QLD, 4072, Brisbane, Australia.
authors.forename: Susanne
authors.initials: S
authors.lastname: Schmidt
authors.affiliation: Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83, Umeå, Sweden.|Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83, Umeå, Sweden.
authors.forename: Torgny
authors.initials: T
authors.lastname: Näsholm
mesh_terms: D026923:Amino Acid Transport Systems, Basic / Q000235:genetics* / Q000378:metabolism; D064751:Ammonium Compounds / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D002247:Carbon Isotopes; D002853:Chromatography, Liquid; D018556:Crops, Agricultural / Q000378:metabolism*; D004058:Diffusion; D005838:Genotype; D005973:Glutamine / Q000378:metabolism; D013058:Mass Spectrometry; D009154:Mutation / Q000235:genetics*; D038821:Mycorrhizae / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism*; D009587:Nitrogen Isotopes; D018517:Plant Roots / Q000378:metabolism; D012987:Soil / Q000737:chemistry*; D013997:Time Factors
chemical_list: D026923:Amino Acid Transport Systems, Basic; D064751:Ammonium Compounds; D029681:Arabidopsis Proteins; D002247:Carbon Isotopes; C110638:LHT1 protein, Arabidopsis; D009587:Nitrogen Isotopes; D012987:Soil; D005973:Glutamine; D009584:Nitrogen