title: Enhancement of tolerance of Indian mustard (Brassica juncea) to mercury by carbon monoxide.
abstract: Carbon monoxide (CO) is a hazardous gaseous molecule, whose concentration in atmosphere is recently rising. CO also is an endogenous regulator of a variety of biological processes in animals and plants. However, whether CO regulates plant adaptation to Hg-contaminated environments is unknown. In this study, we investigated the effect of CO on biological responses of Indian mustard (Brassica juncea), a plant species frequently used for heavy metal accumulation, to mercury (Hg) toxicity. Exposure of B. juncea to Hg(II) triggered production of O(2)(-) and H(2)O(2) as well as peroxides. However, such an effect can be reversed by CO exposure. Plants treated with 0.2 mM CO accumulated less amounts of Hg and had improved root elongation. Treatment with CO reduced activities of superoxide dismutase and increased activities of catalase, ascorbate peroxidase and guaiacol peroxidase in Hg-treated plants. CO-mediated alleviation of Hg toxicity was closely related to the accumulated proline, an antioxidant and reduced non-protein thiols, a sulfhydryl-containing compound that has strong capability for chelating heavy metals. These results indicate that CO plays a crucial role in preventing the plant from Hg toxicity.
authors.affiliation: Department of Biochemistry and Molecular Biology, College of Life Science, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: De Kun
authors.initials: de K
authors.lastname: Meng
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
authors.forename: Zhi Min
authors.initials: ZM
authors.lastname: Yang
mesh_terms: D060387:Ascorbate Peroxidases; D002248:Carbon Monoxide / Q000494:pharmacology*; D002374:Catalase / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D052918:Environmental Restoration and Remediation; D015227:Lipid Peroxidation; D017669:Mercury Compounds / Q000633:toxicity*; D009149:Mustard Plant / Q000187:drug effects*; D009195:Peroxidase / Q000737:chemistry; D010544:Peroxidases / Q000737:chemistry; D018517:Plant Roots / Q000187:drug effects; D018749:RNA, Plant / Q000235:genetics; D017382:Reactive Oxygen Species / Q000737:chemistry; D012989:Soil Pollutants / Q000737:chemistry / Q000633:toxicity; D013482:Superoxide Dismutase / Q000737:chemistry / Q000378:metabolism
chemical_list: D017669:Mercury Compounds; D018749:RNA, Plant; D017382:Reactive Oxygen Species; D012989:Soil Pollutants; D002248:Carbon Monoxide; D010544:Peroxidases; C121048:guaiacol peroxidase; D060387:Ascorbate Peroxidases; D002374:Catalase; D009195:Peroxidase; D013482:Superoxide Dismutase