Oxidative stress is a consequence, not a cause, of aluminum toxicity in the forage legume Lotus corniculatus

Author(s)

Joaquin Navascues, Carmen Perez-Rontome, Diego H. Sanchez, Christiana Staudinger, Stefanie Wienkoop, Ruben Rellan-Alvarez, Manuel Becana

Abstract

• Aluminum (Al) toxicity is a major limiting factor of crop production on acid soils, but the

implication of oxidative stress in this process is controversial. A multidisciplinary approach was

used here to address this question in the forage legume Lotus corniculatus.

• Plants were treated with low Al concentrations in hydroponic culture, and physiological and

biochemical parameters, together with semiquantitative metabolic and proteomic profiles,

were determined.

• The exposure of plants to 10 lM Al inhibited root and leaf growth, but had no effect on

the production of reactive oxygen species or lipid peroxides. By contrast, exposure to 20 lM

Al elicited the production of superoxide radicals, peroxide and malondialdehyde. In response

to Al, there was a progressive replacement of the superoxide dismutase isoforms in the cytosol,

a loss of ascorbate and consistent changes in amino acids, sugars and associated enzymes.

• We conclude that oxidative stress is not a causative factor of Al toxicity. The increased

contents in roots of two powerful Al chelators, malic and 2-isopropylmalic acids, together with

the induction of an Al-activated malate transporter gene, strongly suggest that both organic

acids are implicated in Al detoxification. The effects of Al on key proteins involved in cytoskeleton

dynamics, protein turnover, transport, methylation reactions, redox control and

stress responses underscore a metabolic dysfunction, which affects multiple cellular compartments,

particularly in plants exposed to 20 lM Al.

Organisation(s)

External organisation(s)

Estación Experimental de Aula Dei - CSIC, Max-Planck-Institut für Molekulare Pflanzenphysiologie

Journal

New Phytologist

Volume

193

Pages

625-636

No. of pages

ISSN

0028-646X

DOI

https://doi.org/10.1111/j.1469-8137.2011.03978.x

Publication date

2012

Peer reviewed

Yes

Austrian Fields of Science 2012

106027 Ecotoxicology, 106031 Plant physiology

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