title: Involvement of NO and ROS in sulfur dioxide induced guard cells apoptosis in Tagetes erecta.
abstract: Both nitric oxide (NO) and reactive oxygen species (ROS) are very important signal molecules, but the roles they play in signal transduction of sulfur dioxide (SO2) induced toxicities on ornamental plants is not clear. In this study, the functions of NO and ROS in SO2-induced death of lower epidermal guard cells in ornamental plant Tagetes erecta were investigated. The results showed that SO2 derivatives (0.4-4.0 mmol L(-1) of final concentrations) could reduce the guard cells' viability and increase their death rates in a dose-dependent manner. Meanwhile, the significant increase of cellular NO, ROS, and Ca(2+) levels (P<0.05) and typical apoptosis features including nucleus condensation, nucleus break and nucleus fragmentation were observed. However, exposure to 2.0 mmol L(-1) of SO2 derivatives combined with either NO antagonists (NO scavenger c-PTIO; nitrate reductase inhibitor NaN3; NO synthase inhibitor L-NAME), ROS scavenger (AsA or CAT) or Ca(2+) antagonists (Ca(2+) scavenger EGTA or plasma membrane Ca(2+) channel blocker LaCl3) can effectively block SO2-induced guard cells death and corresponding increase of NO, ROS and Ca(2+) levels. In addition, addition of L-NAME or AsA in 2.0 mmol L(-1) of SO2 derivatives led to significant decrease in the levels of NO, ROS and Ca(2+), whereas addition of LaCl3 in them just resulted in the decrease of Ca(2+) levels, hardly making effects on NO and ROS levels. It was concluded that NO and ROS were involved in the apoptosis induced by SO2 in T. erecta, which regulated the cell apoptosis at the upstream of Ca(2+).
authors: Department of Biology, Taiyuan Normal University, Taiyuan 030031, China.
authors: Aili
authors: A
authors: Wei
authors: Institute of Horticulture, Shanxi Academy of Agricultural Sciences, Taiyuan 030031, China. Electronic address: sxyyfbc@163.com.
authors: Baocun
authors: B
authors: Fu
authors: Institute of Horticulture, Shanxi Academy of Agricultural Sciences, Taiyuan 030031, China. Electronic address: 13903409005@163.com.
authors: Yunshan
authors: Y
authors: Wang
authors: Department of Biology, Taiyuan Normal University, Taiyuan 030031, China. Electronic address: 1227652138@qq.com.
authors: Xiaoyan
authors: X
authors: Zhai
authors: Department of Plant Biology and Ecology, College of Life Science, Nankai University, Tianjin 300071, China. Electronic address: 1160044592@qq.com.
authors: Xiaojing
authors: X
authors: Xin
authors: Institute of Horticulture, Shanxi Academy of Agricultural Sciences, Taiyuan 030031, China. Electronic address: 25589597@qq.com.
authors: Chao
authors: C
authors: Zhang
authors: Institute of Horticulture, Shanxi Academy of Agricultural Sciences, Taiyuan 030031, China. Electronic address: caodm787@sohu.com.
authors: Dongmei
authors: D
authors: Cao
authors: Department of Biology, Taiyuan Normal University, Taiyuan 030031, China. Electronic address: 894849294@qq.com.
authors: Xiaobing
authors: X
authors: Zhang
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D017209:Apoptosis / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D019441:Plant Epidermis / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013458:Sulfur Dioxide / Q000633:toxicity*; D031686:Tagetes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism
chemical_list: D000393:Air Pollutants; D004791:Enzyme Inhibitors; D017382:Reactive Oxygen Species; D013458:Sulfur Dioxide; D009569:Nitric Oxide; D002118:Calcium
keywords: Guard cell apoptosis; NO; ROS; SO(2); Tagetes erecta