Publication:
Is N-feedback involved in the inhibition of nitrogen fixation in drought-stressed Medicago truncatula?

Date

2013

Director

Publisher

Oxford University Press
Society for Experimental Biology
Acceso abierto / Sarbide irekia
Artículo / Artikulua
Versión publicada / Argitaratu den bertsioa

Project identifier

MICINN//AGL2011-23738/ES/recolecta
MICINN//AGL2011-30386-C02-01/ES/recolecta
European Commission/FP7/253141openaire

Abstract

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.

Description

Keywords

Amino acids, Drought, Local regulation, Medicago truncatula, N-feedback inhibition, Nitrogen fixation, Transpiration

Department

Ciencias del Medio Natural / Natura Ingurunearen Zientziak

Faculty/School

Degree

Doctorate program

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