title: A novel role for cyanide in the control of cucumber (Cucumis sativus L.) seedlings response to environmental stress.
abstract: The effects of potassium cyanide (KCN) pretreatment on the response of cucumber (Cucumis sativus L.) plants to salt, polyethylene glycol (PEG) and cold stress were investigated in the present study. Here, we found that KCN pretreatment improved cucumber seedlings tolerance to stress conditions with maximum efficiency at a concentration of 20 µM. The results showed that pretreatment with 20 µM KCN alleviated stress-induced oxidative damage in plant cells and clearly induced the activity of alternative oxidase (AOX) and the ethylene production. Furthermore, the structures of thylakoids and mitochondria in the KCN-pretreated seedlings were less damaged by the stress conditions, which maintained higher total chlorophyll content, photosynthetic rate and photosystem II (PSII) proteins levels than the control. Importantly, the addition of the AOX inhibitor salicylhydroxamic acid (1 mm; SHAM) decreased plant resistance to environmental stress and even compromised the cyanide (CN)-enhanced stress tolerance. Therefore, our findings provide a novel role of CN in plant against environmental stress and indicate that the CN-enhanced AOX might contribute to the reactive oxygen species (ROS) scavenging and the protection of photosystem by maintaining energy charge homoeostasis from chloroplast to mitochondria.
authors.affiliation: Plant Physiology Laboratory             Key Laboratory of Bio-resources & Eco-environment (Ministry of Education), College of Life Science, Sichuan University, Chengdu 610064, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Xu
authors.forename: Da-Wei
authors.initials: DW
authors.lastname: Zhang
authors.forename: Feng
authors.initials: F
authors.lastname: Zhu
authors.forename: He
authors.initials: H
authors.lastname: Tang
authors.forename: Xin
authors.initials: X
authors.lastname: Lv
authors.forename: Jian
authors.initials: J
authors.lastname: Cheng
authors.forename: Huang-Fan
authors.initials: HF
authors.lastname: Xie
authors.forename: Hong-Hui
authors.initials: HH
authors.lastname: Lin
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D018553:Cucumis sativus / Q000187:drug effects*; D005030:Ethylenes / Q000096:biosynthesis; D018384:Oxidative Stress / Q000187:drug effects; D011190:Potassium Cyanide / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects*; D013312:Stress, Physiological
chemical_list: D000975:Antioxidants; D005030:Ethylenes; D017382:Reactive Oxygen Species; C036216:ethylene; D011190:Potassium Cyanide