Subcellular Localization of Oxygen Defense Enzymes in Soybean (Glycine max [L.] Merr.) Root Nodules

Abstract

Soybean (Glycine max [L.] Merr.) root nodules contain the enzymes of the ascorbate-glutathione pathway to minimize oxidative damage. In the present study, fractionation and immunocytochemistry were used to determine the subcellular location of the enzymes of this pathway. AI1 four enzymes (ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase) were present in the soluble fraction from nodule plant cells and in isolated mitochondria. No activity was detected in peroxisomes. Bacteroids contained glutathione reductase but not the other enzymes of this pathway. lmmunogold localization indicated that ascorbate peroxidase was present in the cytosol of infected and uninfected cells but not in the peribacteroid space. Results of immunogold and immunofluorescence studies indicated that monodehydroascorbate reductase was located primarily in the cell wall, suggesting that ascorbate regeneration in the cytoplasm may proceed primarily through the action of dehydroascorbate reductase. The possible roles of monodehydroascorbate reductase in cell wall metabolism are discussed.

Effect of water stress on antioxidant systems and oxidative parameters in fruits of tomato (Solanum lycopersicon L, cv. Micro-tom)

“…In plants, MDHAR activity has been detected in the chloroplast, mitochondria, peroxisome, cytosol, and associated with the plasma membrane and cell wall (Dalton et al 1993;Leonardis et al 1995;Bérczi and Møller 1998;Mittova et al 2000). In this study, changes in MDHAR activity were varies depending on the development stage and the intensity and duration of water stress, with a marked increase in fruits at the mature green stage of plants stressed for 6 and 10 days (Fig.…”

Genetic background impacts soluble and cell wall-bound aromatics in brown midrib mutants of sorghum

“…Separated proteins were electroblotted to nitrocellulose membranes and probed with antibodies (Xiang et al 2004). Antibodies were generated to soybean root nodule ascorbate peroxidase (Dalton et al 1993) and to recombinant proteins produced in E. coli to the following ESTs: DN143131 = switchgrass CAD; DN143927 = switchgrass CCOMT; CX607415 = sorghum COMT. The coding sequence for COMT was arbitrarily truncated into N-terminal and C-terminal nonoverlapping polypeptides and used to generate polyclonal antibodies in rabbits (N-terminal) and guinea pigs (C-terminal).…”

Oxidative stress induced expression of monodehydroascorbate reductase gene in Eleusine coracana

“…Monodehydroascorbate reductase is ubiquitous in all the phylogenetic groups and its isoforms existing in chloroplasts (Hossain et al 1984), cytosol (Dalton et al 1993), peroxisomes and mitochondria (Jimenez et al 1997) have been reported. The activity of MDAR has been shown to be up-regulated under several stress conditions, for instance in tomato by salinity stress (Mittova et al 2003) and high light intensity (Gechev et al 2003), in rice by low temperature (Oidaira et al 2000), and in Arabidopsis by UV-C exposure (Kubo et al 1999).…”