Arbuscular mycorrhizal symbiosis elicits shoot proteome changes that are modified during cadmium stress alleviation in Medicago truncatula

BMC Plant Biology

Research Article

Samira Aschi-Smiti¹  Martine Bertrand²  Ghislaine Recorbet³  Vivienne Gianinazzi-Pearson³  Franck Robert³  Benoît Schoefs³  Eliane Dumas-Gaudot³  Achref Aloui⁴  Céline Henry⁵ 

[1] Département des Sciences Biologiques, Faculté des Sciences de Tunis, Campus universitaire, 1060, Tunis, Tunisia;Microorganismes, Metaux et Toxicité, Institut National des Sciences et Techniques de la Mer, Conservatoire National des Arts et Métiers, BP 324, 50103, Cherbourg-Octeville, Cedex, France;UMR INRA 1088/CNRS 5184/UB, Plante-Microbe-Environnement. INRA-CMSE, BP 86510, 21065, Dijon Cedex, France;UMR INRA 1088/CNRS 5184/UB, Plante-Microbe-Environnement. INRA-CMSE, BP 86510, 21065, Dijon Cedex, France;Département des Sciences Biologiques, Faculté des Sciences de Tunis, Campus universitaire, 1060, Tunis, Tunisia;Unité de Biochimie Bactérienne, PAPPSO, batiment 526, 78352, Domaine de Vilvert, Jouy en Josas Cedex, France;

关键词: Arbuscular Mycorrhizal;    Electron Transport Rate;    Mycorrhizal Plant;    Heavy Metal Stress;    Maximum Quantum Yield;   

DOI  :  10.1186/1471-2229-11-75

 received in 2010-11-02, accepted in 2011-05-05,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundArbuscular mycorrhizal (AM) fungi, which engage a mutualistic symbiosis with the roots of most plant species, have received much attention for their ability to alleviate heavy metal stress in plants, including cadmium (Cd). While the molecular bases of Cd tolerance displayed by mycorrhizal plants have been extensively analysed in roots, very little is known regarding the mechanisms by which legume aboveground organs can escape metal toxicity upon AM symbiosis. As a model system to address this question, we used Glomus irregulare-colonised Medicago truncatula plants, which were previously shown to accumulate and tolerate heavy metal in their shoots when grown in a substrate spiked with 2 mg Cd kg-1.ResultsThe measurement of three indicators for metal phytoextraction showed that shoots of mycorrhizal M. truncatula plants have a capacity for extracting Cd that is not related to an increase in root-to-shoot translocation rate, but to a high level of allocation plasticity. When analysing the photosynthetic performance in metal-treated mycorrhizal plants relative to those only Cd-supplied, it turned out that the presence of G. irregulare partially alleviated the negative effects of Cd on photosynthesis. To test the mechanisms by which shoots of Cd-treated mycorrhizal plants avoid metal toxicity, we performed a 2-DE/MALDI/TOF-based comparative proteomic analysis of the M. truncatula shoot responses upon mycorrhization and Cd exposure. Whereas the metal-responsive shoot proteins currently identified in non-mycorrhizal M. truncatula indicated that Cd impaired CO2 assimilation, the mycorrhiza-responsive shoot proteome was characterised by an increase in photosynthesis-related proteins coupled to a reduction in glugoneogenesis/glycolysis and antioxidant processes. By contrast, Cd was found to trigger the opposite response coupled the up-accumulation of molecular chaperones in shoot of mycorrhizal plants relative to those metal-free.ConclusionBesides drawing a first picture of shoot proteome modifications upon AM symbiosis and/or heavy metal stress in legume plants, the current work argues for allocation plasticity as the main driving force for Cd extraction in aboveground tissues of M. truncatula upon mycorrhization. Additionally, according to the retrieved proteomic data, we propose that shoots of mycorrhizal legume plants escape Cd toxicity through a metabolic shift implying the glycolysis-mediated mobilization of defence mechanisms at the expense of the photosynthesis-dependent symbiotic sucrose sink.

【 授权许可】

Unknown   
© Aloui et al; licensee BioMed Central Ltd. 2011. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.