Physiological Roles of GlutathioneS-Transferases in Soybean Root Nodules      

Abstract

Glutathione S-transferases (GSTs) are ubiquitous enzymes that catalyze the conjugation of toxic xenobiotics and oxidatively produced compounds to reduced glutathione, which facilitates their metabolism, sequestration, or removal. We report here that soybean (Glycine max) root nodules contain at least 14 forms of GST, with GST9 being most prevalent, as measured by both real-time reverse transcription-polymerase chain reaction and identification of peptides in glutathione-affinity purified extracts. GST8 was prevalent in stems and uninfected roots, whereas GST2/10 prevailed in leaves. Purified, recombinant GSTs were shown to have wide-ranging kinetic properties, suggesting that the suite of GSTs could provide physiological flexibility to deal with numerous stresses. Levels of GST9 increased with aging, suggesting a role related to senescence. RNA interference studies of nodules on composite plants showed that a down-regulation of GST9 led to a decrease in nitrogenase (acetylene reduction) activity and an increase in oxidatively damaged proteins. These findings indicate that GSTs are abundant in nodules and likely function to provide antioxidant defenses that are critical to support nitrogen fixation.

Coordinate induction of antioxidant defense and glyoxalase system by exogenous proline and glycinebetaine is correlated with salt tolerance in mung bean

“…GSTs are best known for the detoxification of xenobiotics, but they can also act as antioxidants by tagging oxidative degradation products for removal. GSTs act by catalyzing the conjugation of GSH with electrophilic, often hydrophobic toxic compounds to form derivates that can be secreted from the cells, sequestered in the vacuole, or catabolized (Dalton et al, 2009). In addition to GST, GPX catalyzes the GSH-dependent reduction of H 2 O 2 and organic peroxides, including lipid peroxides, to water or alcohols, thus helping to protect the plant cells against the oxidative damage (Eshdat et al, 1997).…”

Glutathione-Indole-3-Acetonitrile Is Required for Camalexin Biosynthesis in Arabidopsis thaliana

“…Multiple GSTFs, including GSTF2, GSTF6, and GSTF7, accumulated at high levels following MKK9 DD protein induction. GSTs are a class of important enzymes that are involved in plant growth, development, and stress responses (Moons, 2005;Dalton et al, 2009;Dixon et al, , 2010Sappl et al, 2009;Townsend et al, 2009). Interestingly, each of the abovementioned GSTFs was represented by two protein spots: spots 14 and 22 represented GSTF2, spots 18 and 21 represented GSTF6, and spots 9 and 11 represented GSTF7.…”

Comparative Investigation of Glutathione S-transferase (GST) in Different Crops and Purification of High Active GSTs from Onion (Allium cepa L.)

“…BARI Sarisha11, 13 and 14 from Brassica juncea, B. napus and B. rapa, respectively (Fig. 1) protein).GST activity has been reported in to increase under biotic and abiotic stress in Brassica spp [48,49], in safflower [50], in soybean [51,52]. Role of GST also reported for root nodule formation in soybean [53].On the other hand role of GST has been reported in sunflower under biotic stress (However, role of GST has not yet been reported for oil crop like sunflower sesame, linseed and niger though, they contains some medical values..…”