title: Regulation of amino acid uptake by carbon and nitrogen in Pinus sylvestris.
abstract: The simultaneous uptake of 13 different amino acids by Scots pine ( Pinus sylvestris L.) was characterized and its regulation investigated after pre-treatments with a range of C and N metabolites. The uptake system exhibited a broad substrate specificity, acquiring all tested amino acids at similar uptake rates. Uptake of all tested amino acids by excised roots was linear over a time period of 150 min and exhibited pH-dependency, showing a peak at pH 4.0-5.0. Uptake was increased following pre-treatments with glucose and sucrose, while ammonium pre-treatments had a negative effect on amino acid acquisition. Pre-treatments with the important Krebs cycle intermediates oxaloacetate or 2-oxoglutarate did not result in altered amino acid uptake. It is speculated that the up-regulation of uptake may be due to an increased flow of glucose through a sensor mechanism, such as hexokinase. The regulation of transport by N and C suggests a function for amino acid uptake in the N nutrition of the plant, thus further highlighting the importance of organic nitrogen for plant N nutrition suggested by an increasing amount of research.
authors.affiliation: Umeå Plant Science Center, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 90183, Umeå, Sweden. jorgen.persson@genfys.slu.se
authors.forename: Jörgen
authors.initials: J
authors.lastname: Persson
authors.forename: Torgny
authors.initials: T
authors.lastname: Näsholm
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D001692:Biological Transport / Q000187:drug effects; D002244:Carbon / Q000378:metabolism*; D005947:Glucose / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007656:Ketoglutaric Acids / Q000494:pharmacology; D009584:Nitrogen / Q000378:metabolism*; D062907:Oxaloacetic Acid / Q000494:pharmacology; D028223:Pinus / Q000187:drug effects / Q000378:metabolism*; D041605:Pinus sylvestris; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism; D013379:Substrate Specificity; D013395:Sucrose / Q000494:pharmacology
chemical_list: D000596:Amino Acids; D007656:Ketoglutaric Acids; D062907:Oxaloacetic Acid; D013395:Sucrose; D002244:Carbon; D005947:Glucose; D009584:Nitrogen