Ulrika Ganeteg1, Iftikhar Ahmad1, Sandra Jämtgård2, Camila Aguetoni-Cambui1, Erich Inselsbacher2,3, Henrik Svennerstam1, Susanne Schmidt4, Torgny Näsholm1,2. 1. Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83, Umeå, Sweden. 2. Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83, Umeå, Sweden. 3. University of Vienna, Department of Geography and Regional Research, Vienna, AT-1090, Austria. 4. School of Agriculture and Food Sciences, The University of Queensland, QLD, 4072, Brisbane, Australia.
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 of 13 C and 15 N label and of U-13 C5 ,15 N2 L-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 of 13 C-labelled carbon and 15 N-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 δ15 N abundance suggesting their dependence on different N pools. Our data show that LHT1 expression is crucial for plant uptake of organic N from soil.
Although organic nitrogen (n class="Chemical">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 of 13 C and 15 N label and of U-13 C5 ,15 N2 L-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 of 13 C-labelled carbon and 15 N-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 δ15 N 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: Johanna Carlsson; Henrik Svennerstam; Thomas Moritz; Ulrika Egertsdotter; Ulrika Ganeteg Journal: PLoS One Date: 2017-08-24 Impact factor: 3.240