title: Changes in plastid proteome and structure in arbuscular mycorrhizal roots display a nutrient starvation signature.
abstract: During arbuscular mycorrhizal symbiosis, arbuscule-containing root cortex cells display a proliferation of plastids, a feature usually ascribed to an increased plant anabolism despite the lack of studies focusing on purified root plastids. In this study, we investigated mycorrhiza-induced changes in plastidic pathways by performing a label-free comparative subcellular quantitative proteomic analysis targeted on plastid-enriched fractions isolated from Medicago truncatula roots, coupled to a cytological analysis of plastid structure. We identified 490 root plastid protein candidates, among which 79 changed in abundance upon mycorrhization, as inferred from spectral counting. According to cross-species sequence homology searches, the mycorrhiza-responsive proteome was enriched in proteins experimentally localized in thylakoids, whereas it was depleted of proteins ascribed predominantly to amyloplasts. Consistently, the analysis of plastid morphology using transmission electron microscopy indicated that starch depletion associated with the proliferation of membrane-free and tubular membrane-containing plastids was a feature specific to arbusculated cells. The loss of enzymes involved in carbon/nitrogen assimilation and provision of reducing power, coupled to macromolecule degradation events in the plastid-enriched fraction of mycorrhizal roots that paralleled lack of starch accumulation in arbusculated cells, lead us to propose that arbuscule functioning elicits a nutrient starvation and an oxidative stress signature that may prime arbuscule breakdown.
authors: Agroécologie, AgroSup Dijon, CNRS, INRA, Univ. Bourgogne Franche-Comté, Pôle Interactions Plantes Microrganismes, Dijon cedex 21065, France.
authors: Zeina
authors: Z
authors: Daher
authors: Agroécologie, AgroSup Dijon, CNRS, INRA, Univ. Bourgogne Franche-Comté, Pôle Interactions Plantes Microrganismes, Dijon cedex 21065, France.
authors: Ghislaine
authors: G
authors: Recorbet
authors: Department of Plant Anatomy, Eötvös Loránd University, Budapest H-1117, Hungary.
authors: Katalin
authors: K
authors: Solymosi
authors: Department of Molecular System Biology, University of Vienna, Vienna 1090, Austria.
authors: Stefanie
authors: S
authors: Wienkoop
authors: Agroécologie, AgroSup Dijon, CNRS, INRA, Univ. Bourgogne Franche-Comté, Pôle Interactions Plantes Microrganismes, Dijon cedex 21065, France.
authors: Arnaud
authors: A
authors: Mounier
authors: Agroécologie, AgroSup Dijon, CNRS, INRA, Univ. Bourgogne Franche-Comté, Pôle Interactions Plantes Microrganismes, Dijon cedex 21065, France.
authors: Dominique
authors: D
authors: Morandi
authors: Agroécologie, AgroSup Dijon, CNRS, INRA, Univ. Bourgogne Franche-Comté, Pôle Interactions Plantes Microrganismes, Dijon cedex 21065, France.
authors: Jeannine
authors: J
authors: Lherminier
authors: Agroécologie, AgroSup Dijon, CNRS, INRA, Univ. Bourgogne Franche-Comté, Pôle Interactions Plantes Microrganismes, Dijon cedex 21065, France.
authors: Daniel
authors: D
authors: Wipf
authors: Agroécologie, AgroSup Dijon, CNRS, INRA, Univ. Bourgogne Franche-Comté, Pôle Interactions Plantes Microrganismes, Dijon cedex 21065, France.
authors: Eliane
authors: E
authors: Dumas-Gaudot
authors: MicroMar, Mer, Molécules, Santé, UBL, Université du Maine, Le Mans Cedex 9 72085, France.
authors: Benoît
authors: B
authors: Schoefs
mesh_terms: D018506:Gene Expression Regulation, Plant; D046913:Medicago truncatula / Q000382:microbiology / Q000502:physiology* / Q000648:ultrastructure; D038821:Mycorrhizae / Q000502:physiology* / Q000648:ultrastructure; D010940:Plant Proteins / Q000378:metabolism; D018517:Plant Roots / Q000382:microbiology / Q000502:physiology / Q000648:ultrastructure; D018087:Plastids / Q000378:metabolism / Q000648:ultrastructure; D020543:Proteome; D040901:Proteomics; D013559:Symbiosis
chemical_list: D010940:Plant Proteins; D020543:Proteome