Drought stress provokes the down-regulation of methionine and ethylene biosynthesis pathways in [i]Medicago truncatula[/i] roots and nodules
2014
Larrainzar, Estibaliz | Molenaar, Johanna A. | Wienkoop, Stefanie | Gil-Quintana, Erena | Alibert, Benedicte | Limami, Anis-Mohamed | Arrese-Igor, Cesar | Gonzalez, Esther M. | Dpto Ciencias del Medio Natural ; Universidad Pública de Navarra [Espagne] = Public University of Navarra (UPNA) | Laboratory of Plant Physiology ; Wageningen University and Research [Wageningen] (WUR) | Department of Molecular Systems Biology ; Universität Wien = University of Vienna | Institut de Recherche en Horticulture et Semences (IRHS) ; Université d'Angers (UA)-Institut National de la Recherche Agronomique (INRA)-AGROCAMPUS OUEST | This work was supported by the Spanish Ministry of Economy and Competitiveness (AGL 2011-23738 and AGL 2011-30386-C02-01)
Symbiotic nitrogen fixation is one of the first physiological processes inhibited in legume plants under water-deficit conditions. Despite the progress made in the last decades, the molecular mechanisms behind this regulation are not fully understood yet. Recent proteomic work carried out in the model legume [i]Medicago truncatula[/i] provided the first indications of a possible involvement of nodule methionine (Met) biosynthesis and related pathways in response to water-deficit conditions. To better understand this involvement, the drought-induced changes in expression and content of enzymes involved in the biosynthesis of Met, S-adenosyl-L-methionine (SAM) and ethylene in[i] M.truncatula[/i] root and nodules were analyzed using targeted approaches. Nitrogen-fixing plants were subjected to a progressive water deficit and a subsequent recovery period. Besides the physiological characterization of the plants, the content of total sulphur, sulphate and main S-containing metabolites was measured. Results presented here show that S availability is not a limiting factor in the drought-induced decline of nitrogen fixation rates in [i]M.truncatula[/i] plants and provide evidences for a down-regulation of the Met and ethylene biosynthesis pathways in roots and nodules in response to water-deficit conditions
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