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Role of glutathione in the growth of Bradyrhizobium sp. (peanut microsymbiont) under different environmental stresses and in symbiosis with the host plant

Authors :
Luciano Sobrevals
Adriana Fabra
Stella Castro
Peter Müller
Source :
Canadian Journal of Microbiology. 52:609-616
Publication Year :
2006
Publisher :
Canadian Science Publishing, 2006.

Abstract

Glutathione (GSH) plays an important role in the defence of microorganisms and plants against different environmental stresses. To determine the role of GSH under different stresses, such as acid pH, saline shock, and oxidative shock, a GSH-deficient mutant (Bradyrhizobium sp. 6144-S7Z) was obtained by disruption of the gshA gene, which encodes the enzyme γ-glutamylcysteine synthetase. Growth of the mutant strain was significantly reduced in liquid minimal saline medium, and the GSH content was very low, about 4% of the wild-type level. The defect, caused by disruption of the gshA gene in the growth of mutant strain, cannot be reversed by the addition of GSH (up to 100 µmol/L) to the liquid minimal saline medium, and the endogenous GSH level was approximately the same as that observed without the addition of GSH. In contrast, the wild-type strain increased the GSH content under these conditions. However, the growth of the mutant strain in a rich medium (yeast extract – mannitol) increased, suggesting that at least some but not all of the functions of GSH could be provided by peptides and (or) amino acids. The symbiotic properties of the mutant were similar to those found in the wild-type strain, indicating that the mutation does not affect the ability of the mutant to form effective nodules.Key words: glutathione, γ-glutamylcysteine synthetase, Bradyrhizobium sp., peanut.

Details

ISSN :
14803275 and 00084166
Volume :
52
Database :
OpenAIRE
Journal :
Canadian Journal of Microbiology
Accession number :
edsair.doi.dedup.....86729a6c805c7e875ef20f17d2fdcfb5
Full Text :
https://doi.org/10.1139/w06-007