title: The Medicago truncatula sucrose transporter family: characterization and implication of key members in carbon partitioning towards arbuscular mycorrhizal fungi.
abstract: We identified de novo sucrose transporter (SUT) genes involved in long-distance transport of sucrose from photosynthetic source leaves towards sink organs in the model leguminous species Medicago truncatula. The identification and functional analysis of sugar transporters provide key information on mechanisms that underlie carbon partitioning in plant-microorganism interactions. In that way, full-length sequences of the M. truncatula SUT (MtSUT) family were retrieved and biochemical characterization of MtSUT members was performed by heterologous expression in yeast. The MtSUT family now comprises six genes which distribute among Dicotyledonous clades. MtSUT1-1 and MtSUT4-1 are key members in regard to their expression profiles in source leaves and sink roots and were characterized as functional H(+)/sucrose transporters. Physiological and molecular responses to phosphorus supply and inoculation by the arbuscular mycorrhizal fungus (AMF) Glomus intraradices was studied by gene expression and sugar quantification analyses. Sucrose represents the main sugar transport form in M. truncatula and the expression profiles of MtSUT1-1, MtSUT2, and MtSUT4-1 highlight a fine-tuning regulation for beneficial sugar fluxes towards the fungal symbiont. Taken together, these results suggest distinct functions for proteins from the SUT1, SUT2, and SUT4 clades in plant and in biotrophic interactions.
authors.affiliation: UMR INRA 1347, Agrosup, Université de Bourgogne, Agroécologie, Pôle Interactions Plantes Microorganismes ERL CNRS 6300, BP 86510, 21065 Dijon Cedex, France.
authors.forename: Joan
authors.initials: J
authors.lastname: Doidy
authors.forename: Diederik
authors.initials: D
authors.lastname: van Tuinen
authors.forename: Olivier
authors.initials: O
authors.lastname: Lamotte
authors.forename: Marion
authors.initials: M
authors.lastname: Corneillat
authors.forename: Gérard
authors.initials: G
authors.lastname: Alcaraz
authors.forename: Daniel
authors.initials: D
authors.lastname: Wipf
mesh_terms: D002244:Carbon / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D055137:Glomeromycota / Q000502:physiology*; D046913:Medicago truncatula / Q000235:genetics / Q000254:growth & development / Q000378:metabolism* / Q000382:microbiology*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D038821:Mycorrhizae / Q000502:physiology*; D010710:Phosphates / Q000494:pharmacology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D013559:Symbiosis
chemical_list: D026901:Membrane Transport Proteins; D010710:Phosphates; D010940:Plant Proteins; C078729:sucrose transport protein, plant; D002244:Carbon