title: Cadmium-induced hydrogen sulfide synthesis is involved in cadmium tolerance in Medicago sativa by reestablishment of reduced (homo)glutathione and reactive oxygen species homeostases.
abstract: Until now, physiological mechanisms and downstream targets responsible for the cadmium (Cd) tolerance mediated by endogenous hydrogen sulfide (H2S) have been elusive. To address this gap, a combination of pharmacological, histochemical, biochemical and molecular approaches was applied. The perturbation of reduced (homo)glutathione homeostasis and increased H2S production as well as the activation of two H2S-synthetic enzymes activities, including L-cysteine desulfhydrase (LCD) and D-cysteine desulfhydrase (DCD), in alfalfa seedling roots were early responses to the exposure of Cd. The application of H2S donor sodium hydrosulfide (NaHS), not only mimicked intracellular H2S production triggered by Cd, but also alleviated Cd toxicity in a H2S-dependent fashion. By contrast, the inhibition of H2S production caused by the application of its synthetic inhibitor blocked NaHS-induced Cd tolerance, and destroyed reduced (homo)glutathione and reactive oxygen species (ROS) homeostases. Above mentioned inhibitory responses were further rescued by exogenously applied glutathione (GSH). Meanwhile, NaHS responses were sensitive to a (homo)glutathione synthetic inhibitor, but reversed by the cotreatment with GSH. The possible involvement of cyclic AMP (cAMP) signaling in NaHS responses was also suggested. In summary, LCD/DCD-mediated H2S might be an important signaling molecule in the enhancement of Cd toxicity in alfalfa seedlings mainly by governing reduced (homo)glutathione and ROS homeostases.
authors.affiliation: College of Life Sciences, Laboratory Center of Life Sciences, Nanjing Agricultural University, Jiangsu Province, Nanjing, China.
authors.forename: Weiti
authors.initials: W
authors.lastname: Cui
authors.affiliation: Key Laboratory of Protection and Development Utilization of Tropical Crop Germplasm Resources, Hainan University, Haikou, China.
authors.forename: Huiping
authors.initials: H
authors.lastname: Chen
authors.affiliation: College of Life Sciences, Laboratory Center of Life Sciences, Nanjing Agricultural University, Jiangsu Province, Nanjing, China.
authors.forename: Kaikai
authors.initials: K
authors.lastname: Zhu
authors.affiliation: College of Life Sciences, Laboratory Center of Life Sciences, Nanjing Agricultural University, Jiangsu Province, Nanjing, China.
authors.forename: Qijiang
authors.initials: Q
authors.lastname: Jin
authors.affiliation: College of Life Sciences, Laboratory Center of Life Sciences, Nanjing Agricultural University, Jiangsu Province, Nanjing, China.
authors.forename: Yanjie
authors.initials: Y
authors.lastname: Xie
authors.affiliation: College of Life Sciences, Laboratory Center of Life Sciences, Nanjing Agricultural University, Jiangsu Province, Nanjing, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Cui
authors.affiliation: College of Life Sciences, Laboratory Center of Life Sciences, Nanjing Agricultural University, Jiangsu Province, Nanjing, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Xia
authors.affiliation: College of Life Sciences, Laboratory Center of Life Sciences, Nanjing Agricultural University, Jiangsu Province, Nanjing, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.affiliation: College of Life Sciences, Laboratory Center of Life Sciences, Nanjing Agricultural University, Jiangsu Province, Nanjing, China.
authors.forename: Wenbiao
authors.initials: W
authors.lastname: Shen
mesh_terms: D002104:Cadmium / Q000633:toxicity*; D003542:Cystathionine gamma-Lyase / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism*; D006862:Hydrogen Sulfide / Q000378:metabolism*; D000455:Medicago sativa / Q000201:enzymology / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D036226:Seedlings / Q000201:enzymology / Q000378:metabolism; D012989:Soil Pollutants / Q000633:toxicity*; D013440:Sulfides / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D012989:Soil Pollutants; D013440:Sulfides; D002104:Cadmium; D003542:Cystathionine gamma-Lyase; C025451:sodium bisulfide; D005978:Glutathione; D006862:Hydrogen Sulfide