title: Involvement of NADPH oxidase in sulfur dioxide-induced oxidative stress in plant cells.
abstract: Bisulfite, a major form of SO2 in aqueous phase of apoplast, may reduce photosynthesis rate and thereby crop yield through inducing reactive oxygen species (ROS). In this study, ROS production was directly detected in a living cell of leaf of spinach (Spinacia oleracea L.) using laser scanning confocal microscopes with the assistance of the fluorescence probe dichlorofluorescin diacetate (H2DCF-DA). Results showed that, under bisulfite stress, a large quantity of ROS indicated by DCF fluorescence was produced in epidermic tissue. The role of plasma membrane (PM) NADPH oxidase in bisulfite-induced ROS production was also investigated. Treatment with bisulfite resulted in a significant increase in the content of ROS and the activity of PM NADPH oxidase in spinach leaves. The effects caused by bisulfite were inhibited pronouncedly by pretreatment with two widely used NADPH oxidase inhibitors (diphenyleneiodonium and quinacrine). Moreover, the change patterns of the bisulfite-induced increase and inhibitor-caused decrease in the two parameters were quite similar. Additionally, only a small amount of ROS could be observed on in vitro chloroplasts under bisulfite stress. Based on all the results, we conclude that ROS is involved in bisulfite-induced stress, and the bisulfite-induced enhancements in levels of ROS originate mainly from PM NADPH oxidase.
authors.affiliation: MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, South China Normal University, Guangzhou, 510631, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Li
authors.forename: Da
authors.initials: D
authors.lastname: Xing
authors.forename: Lingrui
authors.initials: L
authors.lastname: Zhang
mesh_terms: D002462:Cell Membrane / Q000201:enzymology; D002736:Chloroplasts / Q000187:drug effects / Q000378:metabolism; D019255:NADPH Oxidases / Q000032:analysis / Q000378:metabolism*; D018384:Oxidative Stress; D010788:Photosynthesis / Q000187:drug effects*; D059828:Plant Cells; D010940:Plant Proteins / Q000032:analysis / Q000378:metabolism*; D010944:Plants / Q000187:drug effects / Q000201:enzymology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D018724:Spinacia oleracea / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D013447:Sulfites / Q000633:toxicity; D013458:Sulfur Dioxide / Q000633:toxicity*
chemical_list: D010940:Plant Proteins; D017382:Reactive Oxygen Species; D013447:Sulfites; D013458:Sulfur Dioxide; D019255:NADPH Oxidases; C042345:hydrogen sulfite