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Modulation du métabolisme azoté sous hypoxie racinaire, chez Medicago truncatula

Abstract : Plants grow in a dynamic environment, which often, imposes constraints on growth and development. Among the adverse environmental factors commonly encountered by land plants, flooding or waterlogging which imposes a temporary root hypoxia (1-2% oxygen). Hypoxia stress jeopardizes plant survival, and therefore induces tremendous damage on the agricultural production and natural ecosystem. Most previous studies of biological and biochemical alterations in plants, due to hypoxic stress, have focused on sugar metabolism. However, few data, regarding the effect of root hypoxia on nitrogen (N) metabolism have recently become available. The aim of our work is to study the impact of root hypoxia on nitrogen metabolism in the model plant "Medicago truncatula." Our results showed that root hypoxia leads to a significant increase in shoot biomass (MF and MS) with increased stem elongation and number of leaves during a transitional period of almost 5 weeks before inducing plant death. Effects on primary metabolism were followed by metabolomic analysis (GC-MS), labeling of nitrogen (15N) and expression of genes involved in nitrogen metabolism. Root hypoxia induced the expected rearrangement of carbon and nitrogen in the root but interestingly it induced significant changes in C and N metabolisms in the aerated shoot. Hypoxia-induced changes in shoot biomass and metabolism were obtained in split-root experiment where only part of the root system was submitted to hypoxia. The response of the aerated shoot to root hypoxia suggests a communication between root and shoot upon hypoxia aiming at a coherent adaptive response at the whole plant level. The nature of this communication deserves to be more thoroughly investigated.
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Submitted on : Friday, January 10, 2014 - 11:10:27 AM
Last modification on : Monday, November 14, 2022 - 1:26:15 AM
Long-term archiving on: : Thursday, April 10, 2014 - 10:35:09 PM

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  • HAL Id : tel-00926762, version 1

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Houssein Diab. Modulation du métabolisme azoté sous hypoxie racinaire, chez Medicago truncatula. Biologie végétale. Université d'Angers, 2013. Français. ⟨NNT : ⟩. ⟨tel-00926762⟩

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