title: Effects of glufosinate on antioxidant enzymes, subcellular structure, and gene expression in the unicellular green alga Chlorella vulgaris.
abstract: Greater exposure to herbicide increases the likelihood of harmful effects in humans and the environment. Glufosinate, a non-selective herbicide, inhibits glutamine synthetase (GS) and thus blocks ammonium assimilation in plants. In the present study, the aquatic unicellular alga Chlorella vulgaris was chosen to assess the effects of acute glufosinate toxicity. We observed physiological changes during 12-96 h of exposure, and gene transcription during 6-48 h of exposure. Exposure to glufosinate increased malondialdehyde content by up to 2.73 times compared with the control, suggesting that there was some oxidative damage. Electron microscopy also showed that there were some chloroplast abnormalities in response to glufosinate. The activities of the antioxidant enzymes superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) also increased markedly in the presence of glufosinate. Maximum activities of SOD, POD, and CAT were 2.90, 2.91, and 2.48 times that of the control, respectively. These elevated activities may help alleviate oxidative damage. A real-time polymerase chain reaction (PCR) assay showed changes in transcript abundances of three photosynthetic genes, psaB, psbC, and rbcL. The results showed that glufosinate reduced the transcript abundances of the three genes after 12h exposure. The lowest abundances of psaB, psbC and rbcL transcripts in response to glufosinate exposure were 38%, 16% and 43% of those of the control, respectively. Our results demonstrate that glufosinate affects the activities of antioxidant enzymes, disrupts chloroplast ultrastructure, and reduces transcription of photosynthesis-related genes in C. vulgaris.
authors.affiliation: College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, People's Republic of China.
authors.forename: Haifeng
authors.initials: H
authors.lastname: Qian
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.forename: G Daniel
authors.initials: GD
authors.lastname: Sheng
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Xu
authors.forename: Weiping
authors.initials: W
authors.lastname: Liu
authors.forename: Zhengwei
authors.initials: Z
authors.lastname: Fu
mesh_terms: D000613:Aminobutyrates / Q000633:toxicity*; D000704:Analysis of Variance; D002374:Catalase / Q000378:metabolism; D048408:Chlorella vulgaris / Q000187:drug effects* / Q000201:enzymology / Q000648:ultrastructure; D002736:Chloroplasts / Q000187:drug effects / Q000648:ultrastructure; D017931:DNA Primers / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects*; D006540:Herbicides / Q000633:toxicity*; D008315:Malondialdehyde / Q000378:metabolism; D046529:Microscopy, Electron, Transmission; D009195:Peroxidase / Q000378:metabolism; D045331:Photosystem I Protein Complex / Q000378:metabolism; D012273:Ribulose-Bisphosphate Carboxylase / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D000613:Aminobutyrates; D017931:DNA Primers; D006540:Herbicides; D045331:Photosystem I Protein Complex; C089909:photosystem I, psaB subunit; D008315:Malondialdehyde; C003121:phosphinothricin; D002374:Catalase; D009195:Peroxidase; D013482:Superoxide Dismutase; C101625:RbcL protein, plastid; D012273:Ribulose-Bisphosphate Carboxylase