Exogenous Glutathione Increases Arsenic Translocation Into Shoots and Alleviates Arsenic-Induced Oxidative Stress by Sustaining Ascorbate-Glutathione Homeostasis in Rice Seedlings.

Ha-Il Jung,Bok-Rye Lee,Myung-Suk Kong,Goo-Bok Jung,Yoo-Hak Kim,Tae-Hwan Kim,Eun-Jin Lee,Chang-Hoon Lee,Jwa-Kyung Sung,Mi-Jin Chae

doi:10.3389/fpls.2019.01089

Ha-Il Jung, Bok-Rye Lee + Show 8 more

Open Access

https://doi.org/10.3389/fpls.2019.01089

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Abstract

Glutathione (GSH) plays diverse roles in the physiological processes, stress defense, growth, and development of plants. This study investigated the effects of exogenous GSH on the biochemical responses of reactive oxygen species and antioxidant levels in rice (Oryza sativa L. cv. Dasan) seedlings under arsenic (As) stress. As treatment inhibited growth; increased the level of superoxide, hydrogen peroxide, and malondialdehyde; and enhanced the uptake of As by the roots and shoots in hydroponically grown 14-day-old seedlings. Furthermore, it reduced GSH content and GSH redox ratios, which have been correlated with the decrease in ascorbate (AsA) redox state. Whereas the exogenous application of GSH in As-treated seedlings reduced As-induced oxidative stress, improved antioxidant defense systems by maintaining antioxidant and/or redox enzyme homeostasis, and increased the AsA and GSH contents, the GSH application also increased the As translocation from the roots to the shoots. These results indicated that the increase in GSH redox state can be linked to an increase in the AsA redox ratio via the induction of the AsA–GSH cycle. Therefore, the results suggest that exogenous GSH application should be a promising approach to enhance As stress resistance in rice plants.

Highlights

Arsenic (As) pollution in agricultural soils and waters, which is rapidly increasing worldwide due to industrialization and urbanization, causes serious environmental issues and adversely influences crop yield and quality (Zhu et al, 2008; Khan et al, 2010; Akinbile and Haque, 2012; Kim et al, 2016)
To evaluate the effect of GSH on As toxicity, the rice seedlings at the four-leaf stage were grown in 15-μM-As-treated hydroponics for 14 days, simultaneously with or without the exogenous GSH treatments (50 and 100 mg kg−1)
GSH is an antioxidant in plants, which is capable of preventing damage to important cellular components caused by reactive oxygen species (ROS), such as O2− and H2O2

Summary

Introduction

Arsenic (As) pollution in agricultural soils and waters, which is rapidly increasing worldwide due to industrialization and urbanization, causes serious environmental issues and adversely influences crop yield and quality (Zhu et al, 2008; Khan et al, 2010; Akinbile and Haque, 2012; Kim et al, 2016). Plants attempt to overcome As toxicity by activating antioxidant scavenging systems that can alleviate the oxidative stress caused by excessive absorption and accumulation of As (Jung et al, 2015; Singh et al, 2016; Sharma et al, 2017). The oxidized form of GSH is GSH disulfide (GSSG), which can be recycled to GSH by GR using reduced nicotinamide adenine dinucleotide phosphate (NADPH) as the electron donor These various components of the AsA–GSH cycle play a pivotal role in a coordinated manner and protect cells against oxidative damage caused by As toxicity (Foyer and Noctor, 2011; Noctor et al, 2012; Dave et al, 2013; Farooq et al, 2016)

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