title: Temporal development of the barley leaf metabolic response to Pilimitation.
abstract: The response of plants to Pilimitation involves interplay between root uptake of Pi, adjustment of resource allocation to different plant organs and increased metabolic Piuse efficiency. To identify potentially novel, early-responding, metabolic hallmarks of Pilimitation in crop plants, we studied the metabolic response of barley leaves over the first 7 d of Pistress, and the relationship of primary metabolites with leaf Pilevels and leaf biomass. The abundance of leaf Pi, Tyr and shikimate were significantly different between low Pi and control plants 1 h after transfer of the plants to low Pi. Combining these data with15N metabolic labelling, we show that over the first 48 h of Pilimitation, metabolic flux through the N assimilation and aromatic amino acid pathways is increased. We propose that together with a shift in amino acid metabolism in the chloroplast a transient restoration of the energetic and redox state of the leaf is achieved. Correlation analysis of metabolite abundances revealed a central role for major amino acids in Pistress, appearing to modulate partitioning of soluble sugars between amino acid and carboxylate synthesis, thereby limiting leaf biomass accumulation when external Piis low.
authors.affiliation: ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, WA6009, Australia.|Centre for Comparative Analysis of Biomolecular Networks, University of Western Australia, Perth, WA6009, Australia.
authors.forename: Ralitza
authors.initials: R
authors.lastname: Alexova
authors.affiliation: ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, WA6009, Australia.|Centre for Comparative Analysis of Biomolecular Networks, University of Western Australia, Perth, WA6009, Australia.
authors.forename: Clark J
authors.initials: CJ
authors.lastname: Nelson
authors.affiliation: ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, WA6009, Australia.|Centre for Comparative Analysis of Biomolecular Networks, University of Western Australia, Perth, WA6009, Australia.
authors.forename: A Harvey
authors.identifier: http://orcid.org/0000-0001-9679-1473
authors.initials: AH
authors.lastname: Millar
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D018533:Biomass; D016000:Cluster Analysis; D001467:Hordeum / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*; D055442:Metabolome / Q000187:drug effects; D009587:Nitrogen Isotopes; D010710:Phosphates / Q000494:pharmacology*; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism*; D013997:Time Factors
chemical_list: D000596:Amino Acids; D009587:Nitrogen Isotopes; D010710:Phosphates
keywords: 15N labelling; Hordeum vulgare; leaves; metabolite profiling; phosphate deficiency