Exogenous Glutathione Alleviation of Cd Toxicity in Italian Ryegrass (Lolium multiflorum) by Modulation of the Cd Absorption, Subcellular Distribution, and Chemical Form

Abstract

Subcellular fractions and the chemical forms of cadmium (Cd) reflect its level of toxicity to plants; however, these effects of exogenous glutathione (GSH) are poorly understood. We exposed two Italian ryegrass (Lolium multiflorum) cultivars (IdyII and Harukaze) to 50 µM Cd or 200 µM GSH to investigate the effect of GSH on the Cd uptake, subcellular compartments, and chemical forms. Cd significantly inhibited the plant growth, while GSH supplementation decreased this inhibition. The application of GSH significantly improved the Cd concentration in the roots but reduced that in the shoots and decreased the Cd translocation from root to shoot. The Cd concentration of the root in the cell wall was increased while the concentration in the soluble fraction was decreased when supplied with GSH. The inorganic form (80% ethanol for Cd extraction) in the roots was significantly reduced when treated with GSH. The Cd form extracted by 2% acetic acid (HAC) with low toxicity and immobility were greatly increased. In leaves, the application GSH decreased in any form of Cd form extracted. In conclusion, exogenous GSH decreased the translocation of Cd and alleviated Italian ryegrass Cd toxicity by accumulating more Cd in the root cell wall and immobilizing more Cd in lower toxicity fractions.

Mitigation of Environmental Stress-Impacts in Plants: Role of Sole and Combinatory Exogenous Application of Glutathione

“…The prominent use of GSH in reducing HM uptake and transport is deemed promising and is being explored extensively by researchers in very recent studies ( Fang et al, 2020 ; Li et al, 2021 ). The uptake and subcellular distribution of Cd in Italian ryegrass ( Lolium multiflorum) under Cd stress and GSH treatment was reported by Fang et al (2020) recently.…”

“…The prominent use of GSH in reducing HM uptake and transport is deemed promising and is being explored extensively by researchers in very recent studies ( Fang et al, 2020 ; Li et al, 2021 ). The uptake and subcellular distribution of Cd in Italian ryegrass ( Lolium multiflorum) under Cd stress and GSH treatment was reported by Fang et al (2020) recently. The results showed an increase in Cd accumulation in roots but a decrease in shoots, proving a decrease in Cd translocation from roots to shoots with the application of GSH.…”

“…This finding proves that the supplementation of GSH improves the vacuolar compartmentalization and is crucial for the detoxification of Cd. ( Fang et al, 2020 ). Through transcriptomic analysis, the expression levels of the Cd transporter, including TaNramp1, TaNramp5, TaHMA2, TaLCT1 on the roots and shoots of wheat plants, were found to be successfully suppressed by the exogenously applied GSH ( Li et al, 2021 ).…”

Exogenous Hemin Confers Cadmium Tolerance by Decreasing Cadmium Accumulation and Modulating Water Status and Matter Accumulation in Maize Seedlings

“…Cd's chemical forms and subcellular distribution directly determine Cd activity in the cell and further reflect the plants' toxicity level [52,53]. NPTs and PCs are important heavy metal chelating agents in plants, which can chelate with Cd ions in the cytoplasm and then be transported to the vacuole to synthesize high molecular complexes with stable properties, thereby alleviating Cd toxicity [54,55].…”

Role of Jasmonates, Calcium, and Glutathione in Plants to Combat Abiotic Stresses Through Precise Signaling Cascade

“…Higher GSH levels halt the translocation of Cd and decreases its lethal effect. GSH treatment also enhances the chlorophyll level, photosynthetic performance and antioxidant capability of plants (Cai et al, 2011a;Fang et al, 2020).…”