This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 140/4/1451    most recent pp.105.070474v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Fecht-Christoffers, M. M. Articles by Horst, W. J. Search for Related Content PubMed PubMed Citation Articles by Fecht-Christoffers, M. M. Articles by Horst, W. J. Agricola Articles by Fecht-Christoffers, M. M. Articles by Horst, W. J.

ENVIRONMENTAL STRESS AND ADAPTATION TO STRESS

The Role of Hydrogen Peroxide-Producing and Hydrogen Peroxide-Consuming Peroxidases in the Leaf Apoplast of Cowpea in Manganese Tolerance^1,[W]

Institute of Plant Nutrition (M.M.F.-C., H.F., W.J.H.) and Department of Applied Genetics (H.-P.B.), University of Hannover, 30419 Hannover, Germany

The apoplast is considered the leaf compartment decisive for manganese (Mn) toxicity and tolerance in cowpea (Vigna unguiculata). Particularly apoplastic peroxidases (PODs) were proposed to be key enzymes in Mn toxicity-induced processes. The presented work focuses on the characterization of the role of hydrogen peroxide (H₂O₂)-producing (NADH peroxidase) and H₂O₂-consuming peroxidase (guaiacol POD) in the apoplastic washing fluid (AWF) of leaves for early stages of Mn toxicity and genotypic differences in Mn tolerance of cowpea. Leaf AWF of the Mn-sensitive cultivar (cv) TVu 91 but not of the Mn-tolerant cv 1987 showed an increase of guaiacol-POD and NADH-peroxidase activities at elevated AWF Mn concentrations. two-dimensional resolutions of AWF proteins revealed that cv TVu 91 expressed more and additional proteins at high Mn treatment, whereas Mn-tolerant cv TVu 1987 remained nearly unaffected. In both cultivars, NADH-peroxidase activity and accompanied H₂O₂ formation rate in vitro were significantly affected by Mn²⁺, p-coumaric acid, and metabolites occurring in the AWF. The total phenol concentration in the AWF was indicative of advanced stages of Mn toxicity but was rather unrelated to early stages of Mn toxicity and genotypic differences in Mn tolerance. The NADH oxidation by AWF PODs was significantly delayed or enhanced in the presence of the protein-free AWF from cv TVu 1987 or cv TVu 91, respectively. High-performance liquid chromatography analysis of AWF indicates the presence of phenols in cv TVu 1987 not observed in cv TVu 91. We conclude from our studies that the H₂O₂-producing NADH peroxidase and its modulation by stimulating or inhibiting phenolic compounds in the leaf apoplast play a major role for Mn toxicity and Mn tolerance in cowpea.

The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Walter Johannes Horst (horst{at}pflern.uni-hannover.de).

^[W] The online version of this article contains Web-only data.

Article, publication date, and citation information can be found at www.plantphysiol.org/cgi/doi/10.1104/pp.105.070474.

^* Corresponding author; e-mail horst{at}pflern.uni-hannover.de; fax 49–511–762–3611.

Received August 25, 2005; returned for revision January 24, 2006; accepted February 6, 2006.

This article has been cited by other articles:

				H. Fuhrs, S. Gotze, A. Specht, A. Erban, S. Gallien, D. Heintz, A. Van Dorsselaer, J. Kopka, H.-P. Braun, and W. J. Horst Characterization of leaf apoplastic peroxidases and metabolites in Vigna unguiculata in response to toxic manganese supply and silicon J. Exp. Bot., April 1, 2009; 60(6): 1663 - 1678. [Abstract] [Full Text] [PDF]

				X. Li, S. Chanroj, Z. Wu, S. M. Romanowsky, J. F. Harper, and H. Sze A Distinct Endosomal Ca2+/Mn2+ Pump Affects Root Growth through the Secretory Process Plant Physiology, August 1, 2008; 147(4): 1675 - 1689. [Abstract] [Full Text] [PDF]

				D. Riewe, L. Grosman, A. R. Fernie, C. Wucke, and P. Geigenberger The Potato-Specific Apyrase Is Apoplastically Localized and Has Influence on Gene Expression, Growth, and Development Plant Physiology, July 1, 2008; 147(3): 1092 - 1109. [Abstract] [Full Text] [PDF]