title: Metabolite transport and associated sugar signalling systems underpinning source/sink interactions.
abstract: Metabolite transport between organelles, cells and source and sink tissues not only enables pathway co-ordination but it also facilitates whole plant communication, particularly in the transmission of information concerning resource availability. Carbon assimilation is co-ordinated with nitrogen assimilation to ensure that the building blocks of biomass production, amino acids and carbon skeletons, are available at the required amounts and stoichiometry, with associated transport processes making certain that these essential resources are transported from their sites of synthesis to those of utilisation. Of the many possible posttranslational mechanisms that might participate in efficient co-ordination of metabolism and transport only reversible thiol-disulphide exchange mechanisms have been described in detail. Sucrose and trehalose metabolism are intertwined in the signalling hub that ensures appropriate resource allocation to drive growth and development under optimal and stress conditions, with trehalose-6-phosphate acting as an important signal for sucrose availability. The formidable suite of plant metabolite transporters provides enormous flexibility and adaptability in inter-pathway coordination and source-sink interactions. Focussing on the carbon metabolism network, we highlight the functions of different transporter families, and the important of thioredoxins in the metabolic dialogue between source and sink tissues. In addition, we address how these systems can be tailored for crop improvement.
authors.affiliation: Plant Biology and Crop Science, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK.
authors.forename: Cara A
authors.initials: CA
authors.lastname: Griffiths
authors.affiliation: Plant Biology and Crop Science, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Paul
authors.affiliation: Centre for Plant Sciences, School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK. Electronic address: c.foyer@leeds.ac.uk.
authors.forename: Christine H
authors.initials: CH
authors.lastname: Foyer
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D001692:Biological Transport / Q000502:physiology*; D050260:Carbohydrate Metabolism / Q000502:physiology*; D002244:Carbon / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D010944:Plants / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D013403:Sugar Phosphates / Q000378:metabolism*; D014199:Trehalose / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D000596:Amino Acids; D013403:Sugar Phosphates; C082722:trehalose-6-phosphate; D002244:Carbon; D014199:Trehalose; D009584:Nitrogen
keywords: Phloem loading; Redox regulation; Source-sink interactions; Sucrose transporters; Sugar signalling; Trehalose