The role of GSTs in the tolerance of Rhizobium leguminosarum to cadmium

Abstract

A high intraspecific difference in cadmium (Cd) tolerance exits among Rhizobium leguminosarum strains. The higher tolerance to Cd appeared to be related to the efficiency of the glutathione (GSH)-Cd chelation mechanism, but it is not known how efficiency is influenced. Thus, in this work it was intended to investigate the traits behind the efficiency of intracellular Cd chelation by GSH. Glutathione-S-transferases (GST; EC 2.5.1.18) are a family of multi-functional dimeric proteins, found in both prokaryotes and eukaryotes, which are implicated in a variety of stress conditions. The common feature of these enzymes is to catalyze the conjugation of the sulfur atom of GSH with a large variety of hydrophobic toxic compounds of both endogenous and exogenous origin. Taking into account the reactions catalyzed by GSTs, it was hypothesized that they could be involved in the GSH-Cd complex formation in R. leguminosarum. Differences in GSTs activity between strains could explain variation in Cd chelation efficiency detected among strains and, consequently, discrepancy in tolerance to Cd. Thus, GST isoforms of R. leguminosarum strains with distinct tolerances to Cd were purified and their activity investigated. The relationship between chelation efficiency and enzymatic activity of GSTs was demonstrated, supporting the hypothesis that GSTs, in particular one isoform, was involved in the formation of GSH-Cd complexes and in the tolerance of Rhizobium to Cd.

Electrosynthesis of acetate from inorganic carbon (HCO3−) with simultaneous hydrogen production and Cd(II) removal in multifunctional microbial electrosynthesis systems (MES)

“…The antioxidative activity of glutathione (GSH), catalase (CAT) and superoxide dismutase (SOD) in the bacteria are expected to be altered by either cadmium sequestration or by scavenging O2•induced by Cd(II), as a defense against the harmful effect of Cd(II) [17][18], while the dehydrogenase activity relates to the biocatalytic ability for hydrogen evolution [19]. These intracellular physiological activities are expected to be altered in the presence of Cd(II) and in the presence of a circuital current in the proposed multifunctional metallurgical MES.…”

Cross-Kingdom Comparative Transcriptomics Reveals Conserved Genetic Modules in Response to Cadmium Stress

“…Intracellular Cd can induce an oxidative stress cascade, for all known tested species, including the ones used in this study ( 73 , 74 ). Due to the high affinity between Cd and sulfur ( 24 ), intracellular Cd can easily bind to thiol-rich GSH ( 75 , 76 ), resulting in GSH depletion ( 30 ). Additionally, Cd competition for S 2− in Fe-S cluster accelerates the Fenton reaction ( 77 ).…”

Do Volatiles Affect Bacteria and Plants in the Same Way? Growth and Biochemical Response of Non-Stressed and Cd-Stressed Arabidopsis thaliana and Rhizobium E20-8

“…To understand the influence of the volatiles in the presence and absence of CdCl 2 in soil bacteria, Rhizobium leguminosarum strain E20-8 (partial 16S rRNA sequence Genbank accession number KY491644) was used. The tolerance level of this strain to Cd was determined previously [ 50 ].…”