The importance of the urea cycle and its relationships to polyamine metabolism during ammonium stress in Medicago truncatula

Date

2022

Authors

Urra Rodríguez, Marina
Cerdán Ruiz, Daniel
Esteban Terradillos, Raquel
Gogorcena, Yolanda
Tavladoraki, Paraskevi

Director

Publisher

Oxford University Press
Acceso abierto / Sarbide irekia
Artículo / Artikulua
Versión publicada / Argitaratu den bertsioa

Project identifier

  • MINECO//AGL2014-52396-P/ES/ recolecta
  • AEI/Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016/AGL2017-83358-R/ES/ recolecta
Impacto
No disponible en Scopus

Abstract

The ornithine–urea cycle (urea cycle) makes a signifcant contribution to the metabolic responses of lower photosynthetic eukaryotes to episodes of high nitrogen availability. In this study, we compared the role of the plant urea cycle and its relationships to polyamine metabolism in ammonium-fed and nitrate-fed Medicago truncatula plants. High ammonium resulted in the accumulation of ammonium and pathway intermediates, particularly glutamine, arginine, ornithine, and putrescine. Arginine decarboxylase activity was decreased in roots, suggesting that the ornithine decarboxylase-dependent production of putrescine was important in situations of ammonium stress. The activity of copper amine oxidase, which releases ammonium from putrescine, was signifcantly decreased in both shoots and roots. In addition, physiological concentrations of ammonium inhibited copper amine oxidase activity in in vitro assays, supporting the conclusion that high ammonium accumulation favors putrescine synthesis. Moreover, early supplementation of plants with putrescine avoided ammonium toxicity. The levels of transcripts encoding urea-cyclerelated proteins were increased and transcripts involved in polyamine catabolism were decreased under high ammonium concentrations. We conclude that the urea cycle and associated polyamine metabolism function as important protective mechanisms limiting ammonium toxicity in M. truncatula. These fndings demonstrate the relevance of the urea cycle to polyamine metabolism in higher plants.

Description

Keywords

Amine oxidase, Ammonium stress, Nitrogen nutrition, Polyamine, Putrescine, Urea cycle

Department

Ciencias / Zientziak / Institute for Advanced Materials and Mathematics - INAMAT2 / Institute for Multidisciplinary Research in Applied Biology - IMAB

Faculty/School

Degree

Doctorate program

item.page.cita

Urra, M.; Buezo, J.; Royo, B.; Cornejo, A.; López-Gómez, P.; Cerdán, D.; Esteban, R.; Martínez-Merino, V.; Gogorcena, Y.; Tavladoraki, P.; Moran, J.F.. (2022). The importance of the urea cycle and its relationships to polyamine metabolism during ammonium stress in Medicago truncatula. Journal of Experimental Botany.

item.page.rights

© The Author(s) 2022. This is an Open Access article distributed under the terms of the Creative Commons Attribution License

Licencia

Los documentos de Academica-e están protegidos por derechos de autor con todos los derechos reservados, a no ser que se indique lo contrario.