title: Glutathione-mediated regulation of nitric oxide, S-nitrosothiol and redox homeostasis confers cadmium tolerance by inducing transcription factors and stress response genes in tomato.
abstract: Glutathione (GSH) plays a critical role in plant growth, development and responses to stress. However, the mechanism by which GSH regulates tolerance to cadmium (Cd) stress still remains unclear. Here we show that inhibition of GSH biosynthesis by buthionine sulfoximine (BSO) aggravated Cd toxicity by increasing accumulation of reactive oxygen species (ROS) and reducing contents of nitric oxide (NO) and S-nitrosothiol (SNO) in tomato roots. In contrast, exogenous GSH alleviated Cd toxicity by substantially minimizing ROS accumulation and increasing contents of NO and SNO, and activities of antioxidant enzymes that eventually reduced oxidative stress. GSH-induced enhancement in Cd tolerance was closely associated with the upregulation of transcripts of several transcription factors such as ETHYLENE RESPONSIVE TRANSCRIPTION FACTOR 1 (ERF1), ERF2, MYB1 TRANSCRIPTION FACTOR- AIM1 and R2R3-MYB TRANSCRIPTION FACTOR- AN2, and some stress response genes. In addition, GSH modulated the cellular redox balance through maintaining increased GSH: GSSG and AsA: DHA ratios, and also increased phytochelatins contents. Nonetheless, GSH-induced alleviation of Cd phytotoxicity was also associated with increased sequestration of Cd into cell walls and vacuoles but not with Cd accumulation. Under Cd stress, while treatment with BSO slightly decreased vacuolar fraction of Cd, combined treatment with BSO and GSH noticeably increased that fraction. Our results suggest that GSH increases tomato tolerance to Cd stress not only by promoting the chelation and sequestration of Cd but also by stimulating NO, SNO and the antioxidant system through a redox-dependent mechanism.
authors.affiliation: Department of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou 310058, PR China.
authors.forename: Md Kamrul
authors.initials: MK
authors.lastname: Hasan
authors.affiliation: Department of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou 310058, PR China.
authors.forename: Congcong
authors.initials: C
authors.lastname: Liu
authors.affiliation: Department of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou 310058, PR China.
authors.forename: Fanan
authors.initials: F
authors.lastname: Wang
authors.affiliation: Department of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou 310058, PR China. Electronic address: ahammed@zju.edu.cn.
authors.forename: Golam Jalal
authors.initials: GJ
authors.lastname: Ahammed
authors.affiliation: Department of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou 310058, PR China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Geological Research Center for Agricultural Applications, China Geological Survey, Xiaojin Road 508, Hangzhou 311203, PR China; Zhejiang Institute of Geological Survey, Xiaojin Road 508, Hangzhou 311203, PR China. Electronic address: xumingxing535005@163.com.
authors.forename: Ming-Xing
authors.initials: MX
authors.lastname: Xu
authors.affiliation: Department of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou 310058, PR China; Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, 866 Yuhangtang Road, Hangzhou 310058, PR China; Key Laboratory of Horticultural Plants Growth, Development and Quality Improvement, Agricultural Ministry of China, Hangzhou 310058, PR China.
authors.forename: Jing-Quan
authors.initials: JQ
authors.lastname: Yu
authors.affiliation: Department of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou 310058, PR China. Electronic address: xiaojianxia@zju.edu.cn.
authors.forename: Xiao-Jian
authors.initials: XJ
authors.lastname: Xia
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D002104:Cadmium / Q000633:toxicity*; D017343:Genes, Plant; D005978:Glutathione / Q000378:metabolism*; D006706:Homeostasis / Q000187:drug effects* / Q000235:genetics; D018551:Solanum lycopersicum / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects / Q000235:genetics; D054811:Phytochelatins / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D026403:S-Nitrosothiols / Q000378:metabolism*; D012989:Soil Pollutants / Q000633:toxicity*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D017382:Reactive Oxygen Species; D026403:S-Nitrosothiols; D012989:Soil Pollutants; D014157:Transcription Factors; D002104:Cadmium; D009569:Nitric Oxide; D054811:Phytochelatins; D005978:Glutathione
keywords: Cadmium; Glutathione; Nitric oxide; Phytochelatin; Tomato; Vacuolar sequestration