Effect of Manganese Toxicity on the Proteome of the Leaf Apoplast in Cowpea

authored by

Marion M. Fecht-Christoffers, Hans Peter Braun, Christelle Lemaitre-Guillier, Alain VanDorsselaer, Walter J. Horst

Abstract

Excess manganese (Mn) supply causes formation of visible brown depositions in the cell walls of leaves of cowpea (Vigna unguiculata), which consist of oxidized Mn and oxidized phenols. Because oxidation of Mn and phenolic compounds in the leaf apoplast was proposed to be catalyzed by apoplastic peroxidases (PODs), induction of these enzymes by Mn excess was investigated. POD activity increased upon prolonged Mn treatment in the leaf tissue. Simultaneously, a significant increase in the concentration of soluble apoplastic proteins in "apoplastic washing fluid" was observed. The identity of the released proteins was systematically characterized by analysis of the apoplast proteome using two-dimensional gel electrophoresis and liquid chromatography-tandem mass spectrometry. Some of the identified proteins exhibit sequence identity to acidic PODs from other plants. Several other proteins show homologies to pathogenesis-related proteins, e.g. glucanase, chitinase, and thaumatin-like proteins. Because pathogenesis-related-like proteins are known to be induced by various other abiotic and biotic stresses, a specific physiological role of these proteins in response to excess Mn supply remains to be established. The specific role of apoplastic PODs in the response of plants to Mn stress is discussed.

Organisation(s)

Institute of Plant Genetics
Institute of Plant Nutrition

Type

Article

Journal

Plant physiology

Volume

133

Pages

1935-1946

No. of pages

12

ISSN

0032-0889

Publication date

12.2003

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Physiology, Genetics, Plant Science

Electronic version(s)

https://doi.org/10.1104/pp.103.029215 (Access: Open)