title: Short-term ammonium supply induces cellular defence to prevent oxidative stress in Arabidopsis leaves.
abstract: Plants can assimilate nitrogen from soil pools of both ammonium and nitrate, and the relative levels of these two nitrogen sources are highly variable in soil. Long-term ammonium nutrition is known to cause damage to Arabidopsis that has been linked to mitochondrial oxidative stress. Using hydroponic cultures, we analysed the consequences of rapid shifts between nitrate and ammonium nutrition. This did not induce growth retardation, showing that Arabidopsis can compensate for the changes in redox metabolism associated with the variations in nitrogen redox status. During the first 3 h of ammonium treatment, we observed distinct transient shifts in reactive oxygen species (ROS), low-mass antioxidants, ROS-scavenging enzymes, and mitochondrial alternative electron transport pathways, indicating rapid but temporally separated changes in chloroplastic, mitochondrial and cytosolic ROS metabolism. The fast induction of antioxidant defences significantly lowered intracellular H2O2levels, and thus protected Arabidopsis leaves from oxidative stress. On the other hand elevated extracellular ROS production in response to ammonium supply may be involved in signalling. The response pattern displays an intricate plasticity of Arabidopsis redox metabolism to minimise stress in responses to nutrient changes.
authors.affiliation: Institute of Experimental Plant Biology and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, 02-096, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Podgórska
authors.affiliation: Institute of Experimental Plant Biology and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, 02-096, Poland.
authors.forename: Maria
authors.initials: M
authors.lastname: Burian
authors.affiliation: Institute of Experimental Plant Biology and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, 02-096, Poland.
authors.forename: Anna M
authors.initials: AM
authors.lastname: Rychter
authors.affiliation: Department of Biology, Lund University, Lund, SE-223 62, Sweden.
authors.forename: Allan G
authors.initials: AG
authors.lastname: Rasmusson
authors.affiliation: Institute of Experimental Plant Biology and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, 02-096, Poland.
authors.forename: Bożena
authors.initials: B
authors.lastname: Szal
mesh_terms: D064751:Ammonium Compounds / Q000494:pharmacology*; D000975:Antioxidants / Q000378:metabolism; D017360:Arabidopsis / Q000187:drug effects* / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D009566:Nitrates / Q000378:metabolism; D010084:Oxidation-Reduction / Q000187:drug effects; D018384:Oxidative Stress / Q000187:drug effects*; D018515:Plant Leaves / Q000187:drug effects* / Q000382:microbiology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D064751:Ammonium Compounds; D000975:Antioxidants; D009566:Nitrates; D017382:Reactive Oxygen Species