Glutathione in plants: biosynthesis and physiological role in environmental stress tolerance

Abstract

Glutathione (GSH; c-glutamyl-cysteinyl-glycine) is a small intracellular thiol molecule which is considered as a strong non-enzymatic antioxidant. Glutathione regulates multiple metabolic functions; for example, it protects membranes by maintaining the reduced state of both a-tocopherol and zeaxanthin, it prevents the oxidative denaturation of proteins under stress conditions by protecting their thiol groups, and it serves as a substrate for both glutathione peroxidase and glutathione S-transferase. By acting as a precursor of phytochelatins, GSH helps in the chelating of toxic metals/metalloids which are then transported and sequestered in the vacuole. The glyoxalase pathway (consisting of glyoxalase I and glyoxalase II enzymes) for detoxification of methylglyoxal, a cytotoxic molecule, also requires GSH in the first reaction step. For these reasons, much attention has recently been directed to elucidation of the role of this molecule in conferring tolerance to abiotic stress. Recently, this molecule has drawn much attention because of its interaction with other signaling molecules and phytohormones. In this review, we have discussed the recent progress in GSH biosynthesis, metabolism and its role in abiotic stress tolerance.

Inhibition of NADP‐malic enzyme activity by H2S and NO in sweet pepper (Capsicum annuum L.) fruits

“…However, other molecules, including glutathione (GSH), with its antioxidant properties, S-nitrosoglutahtione (GSNO), as well as the nitric oxide (NO) reservoir, have important physiological functions (Hogg 2002, Broniowska et al 2013, Corpas et al 2013a, 2013b. Other secondary sulfur compounds, including polysulfides (Münchberg et al 2007), glucosinolates (Hasanuzzaman et al 2017) and phytochelatins, which play important physiological roles, are involved in mechanisms of response to stress (Gupta et al 2013, Ruíz-Torres et al 2017. Hydrogen sulfide (H 2 S), which is generated in the Cys metabolism, is now recognized as an important signaling molecule capable of regulating proteins through a posttranslational modification called persulfidation (Filipovic andJovanovic 2017, Aroca et al 2018).…”

Glutathione foliar fertilisation prevents lime‐induced iron chlorosis in soil grownMedicago scutellata

“…Glutathione (GSH; L‐γ‐glutamyl‐L‐cysteinyl‐glycine; C 10 H 17 N 3 O 6 S) is one of the main antioxidants in plants, and legumes also contain a GSH homolog, homoglutathione (hGSH; C 11 H 19 N 3 O 6 S). Both GSH and hGSH are low molecular weight (307.321 and 321.348 g mol −1 , respectively), water soluble, antioxidant thiol tripeptides that play relevant roles in plant defence, detoxifying ROS and regulating antioxidant enzymes ( Hasanuzzaman et al., ). In M. sativa , hGSH is predominant (98–100% of total GSH + hGSH; Matamoros et al., ; Rellán‐Álvarez et al., ), but there are no published data on M. scutellata .…”

Glutathione and Its Biosynthetic Intermediates Alleviate Cesium Stress in Arabidopsis

“…As sulphur supply alleviates sodium stress but not potassium deficiency stress, this alleviation is not due to the recovery effects against a general nutrition deficiency by another nutrition supply but potentially due to the detoxification effects against xenobiotics. GSH is also known to conjugate with xenobiotics including toxic metals with the aid of GSH S-transferases (GSTs) and to sequestrate them into the vacuoles (Dixon et al, 2002;Hasanuzzaman et al, 2017). As GSTs constitute a large gene family in Arabidopsis, it is intriguing to investigate whether FIGURE 8 | Proposed model for interaction between cesium response and sulphur-mediated alleviation.…”

“…A sulphur-containing metabolite, glutathione (GSH), acts as a strong non-protein antioxidant that protects cells suffering from metal stress which causes oxidative damage (Noctor et al, 2011). GSH and downstream metabolites, phytochelatins (PCs), also function as metal chelators which then sequestrate the metal into vacuoles upon binding, a co mmon detoxi fi cati on strateg y for he av y met als (Hasanuzzaman et al, 2017). Some examples of the interaction between metal stress and the sulphur metabolic pathway in plants are introduced here.…”