title: The endogenous nitric oxide mediates selenium-induced phytotoxicity by promoting ROS generation in Brassica rapa.
abstract: Selenium (Se) is suggested as an emerging pollutant in agricultural environment because of the increasing anthropogenic release of Se, which in turn results in phytotoxicity. The most common consequence of Se-induced toxicity in plants is oxidative injury, but how Se induces reactive oxygen species (ROS) burst remains unclear. In this work, histofluorescent staining was applied to monitor the dynamics of ROS and nitric oxide (NO) in the root of Brassica rapa under Se(IV) stress. Se(IV)-induced faster accumulation of NO than ROS. Both NO and ROS accumulation were positively correlated with Se(IV)-induced inhibition of root growth. The NO accumulation was nitrate reductase (NR)- and nitric oxide synthase (NOS)-dependent while ROS accumulation was NADPH oxidase-dependent. The removal of NO by NR inhibitor, NOS inhibitor, and NO scavenger could alleviate Se(IV)-induced expression of Br_Rbohs coding for NADPH oxidase and the following ROS accumulation in roots, which further resulted in the amelioration of Se(IV)-induced oxidative injury and growth inhibition. Thus, we proposed that the endogenous NO played a toxic role in B. rapa under Se(IV) stress by triggering ROS burst. Such findings can be used to evaluate the toxic effects of Se contamination on crop plants.
authors.affiliation: College of Horticulture, Nanjing Agricultural University, Nanjing, China; Institute of Food Quality and Safety, Jiangsu Academy of Agricultural Sciences, Nanjing, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Food Science, Henan Institute of Science and Technology, Xinxiang, Henan Province, China.
authors.forename: Hai-Zhen
authors.initials: HZ
authors.lastname: Mo
authors.affiliation: Department of Food Science, Henan Institute of Science and Technology, Xinxiang, Henan Province, China.
authors.forename: Liang-Bin
authors.initials: LB
authors.lastname: Hu
authors.affiliation: Institute of Food Quality and Safety, Jiangsu Academy of Agricultural Sciences, Nanjing, China.
authors.forename: You-Qin
authors.initials: YQ
authors.lastname: Li
authors.affiliation: Institute of Food Quality and Safety, Jiangsu Academy of Agricultural Sciences, Nanjing, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
authors.affiliation: College of Horticulture, Nanjing Agricultural University, Nanjing, China.
authors.forename: Li-Fei
authors.initials: LF
authors.lastname: Yang
mesh_terms: D029741:Brassica rapa / Q000187:drug effects / Q000201:enzymology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019255:NADPH Oxidases / Q000378:metabolism; D050901:Nitrate Reductase / Q000037:antagonists & inhibitors / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012643:Selenium / Q000633:toxicity*
chemical_list: D004791:Enzyme Inhibitors; D017382:Reactive Oxygen Species; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D019255:NADPH Oxidases; D050901:Nitrate Reductase; D012643:Selenium