Is N-feedback involved in the inhibition of nitrogen fixation in drought-stressed Medicago truncatula?
Gil Quintana, Erena
Larrainzar Rodríguez, Estíbaliz
Arrese-Igor Sánchez, César
González García, Esther
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Artículo / Artikuluainfo:eu-repo/semantics/article
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Drought stress is a major factor limiting nitrogen fixation (NF) in crop production. However, the regulatory mechanism involved and the origin of the inhibition, whether local or systemic, is still controversial and so far scarcely studied in temperate forage legumes. Medicago truncatula plants were symbiotically grown with a split-root system and exposed to gradual water deprivation. Physiologic ... [++]
Drought stress is a major factor limiting nitrogen fixation (NF) in crop production. However, the regulatory mechanism involved and the origin of the inhibition, whether local or systemic, is still controversial and so far scarcely studied in temperate forage legumes. Medicago truncatula plants were symbiotically grown with a split-root system and exposed to gradual water deprivation. Physiological parameters, NF activity, and amino acid content were measured. The partial drought treatment inhibited NF in the nodules directly exposed to drought stress. Concomitantly, in the droughted below-ground organs, amino acids accumulated prior to any drop in evapotranspiration (ET). It is concluded that drought exerts a local inhibition of NF and drives an overall accumulation of amino acids in diverse plant organs which is independent of the decrease in ET. The general increase in the majority of single amino acids in the whole plant questions the commonly accepted concept of a single amino acid acting as an N-feedback signal. [--]
Amino acids, Drought, Local regulation, Medicago truncatula, N-feedback inhibition, Nitrogen fixation, Transpiration
Oxford University PressSociety for Experimental Biology
Journal of Experimental Botany Vol. 64, No. 1, pp. 281–292, 2013
Universidad Pública de Navarra. Departamento de Ciencias del Medio Natural / Nafarroako Unibertsitate Publikoa. Natura Ingurunearen Zientziak Saila
Versión del editor
This work was financed by the Spanish Ministry of Economy and Competitiveness (AGL 2011–23738 and AGL 2011-30386-C02-01). EG-Q is a holder of a PhD fellowship from the Public University of Navarre (735/2008). EL is a recipient of a Marie Curie International Outgoing Fellowship for Career Development (PIOF-GA-2009–253141).
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