title: Physiological and molecular level effects of silver nanoparticles exposure in rice (Oryza sativa L.) seedlings.
abstract: The physiological and molecular level changes of silver nanoparticles (AgNPs) exposure were investigated in rice (Oryza sativa L.) seedlings. The seedlings were exposed to different concentrations of (0, 0.2, 0.5 and 1 mg L(-1)) AgNPs for one week. Significant reduction in root elongation, shoot and root fresh weights, total chlorophyll and carotenoids contents were observed. Exposure to 0.5 and 1 mg L(-1) of AgNPs caused significant increase in hydrogen peroxide formation and lipid peroxidation in shoots and roots, increased foliar proline accumulation and decreased sugar contents. AgNPs exposure resulted in a dose dependant increase in reactive oxygen species generation and also caused cytotoxicity as evidenced by increased dihydroethidium, 3'-(p-hydroxyphenyl) fluorescein and propidium iodide fluorescence. Tetramethylrhodamine methyl ester assay showed decreased mitochondrial membrane potential with increasing concentrations of AgNPs exposure in roots. Real Time PCR analysis showed differential transcription of genes related to oxidative stress tolerance viz. FSD1, MSD1, CSD1, CSD2, CATa, CATb, CATc, APXa and APXb in shoots and roots of rice seedlings. The overall results suggest that exposure to AgNPs caused significant physiological and molecular level changes, oxidative stress and also resulted in the induction oxidative stress tolerance mechanisms in rice seedlings.
authors.affiliation: Department of Applied Biosciences, College of Life and Environmental Sciences, Konkuk University, Seoul, South Korea.
authors.forename: Prakash M Gopalakrishnan
authors.initials: PM
authors.lastname: Nair
authors.affiliation: Department of Applied Biosciences, College of Life and Environmental Sciences, Konkuk University, Seoul, South Korea. Electronic address: imcim@konkuk.ac.kr.
authors.forename: Ill Min
authors.initials: IM
authors.lastname: Chung
mesh_terms: D050260:Carbohydrate Metabolism / Q000187:drug effects; D002338:Carotenoids / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D053758:Nanoparticles / Q000633:toxicity*; D012275:Oryza / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D018384:Oxidative Stress / Q000187:drug effects; D011392:Proline / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D012834:Silver / Q000737:chemistry* / Q000633:toxicity*; D018675:Toxicity Tests
chemical_list: D017382:Reactive Oxygen Species; D002734:Chlorophyll; D002338:Carotenoids; D012834:Silver; D011392:Proline; D006861:Hydrogen Peroxide
keywords: Cell death; Gene expression; Oryza sativa; Oxidative stress; Reactive oxygen species; Silver nanoparticles