title: Exogenous gamma-aminobutyric acid alleviates oxidative damage caused by aluminium and proton stresses on barley seedlings.
abstract: BACKGROUND
  Proton (H(+)) and aluminium (Al(3+)) toxicities are major factors limiting crop production on acid soils, while gamma-aminobutyric acid (GABA) is a non-protein amino acid involved in various stress tolerances in plants. In this study, to determine whether exogenous GABA is functional in alleviating oxidative stress induced by H(+) and Al(3+) toxicities, the antioxidant defence response regulated by GABA was investigated in barley (Hordeum vulgare L.).
  
  
  RESULTS
  After 24 h treatments of seedlings under H(+), Al(3+) and combined stresses with and without GABA, morphological and biochemical assays were conducted. It was observed that the inhibition of seedling root elongation caused by Al(3+) and H(+) toxicities was significantly mitigated by GABA. The amount of carbonylated proteins with molecular masses of 14.4-97 kDa was decreased. The activities of antioxidant enzymes were enhanced, the content of malondialdehyde was reduced and the accumulation of reactive oxygen species (ROS), as shown by staining roots with nitroblue tetrazolium, declined in GABA-treated seedlings.
  
  
  CONCLUSIONS
  GABA can alleviate oxidative damage caused by H(+) and Al(3+) toxicities in barley seedlings by activating antioxidant defence responses and reducing the elevated levels of carbonylated proteins caused by ROS.
authors.affiliation: The Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou, China.
authors.forename: Hongmiao
authors.initials: H
authors.lastname: Song
authors.forename: Xiangbin
authors.initials: X
authors.lastname: Xu
authors.forename: Hua
authors.initials: H
authors.lastname: Wang
authors.forename: Huizhong
authors.initials: H
authors.lastname: Wang
authors.forename: Yuezhi
authors.initials: Y
authors.lastname: Tao
mesh_terms: D000535:Aluminum / Q000037:antagonists & inhibitors / Q000633:toxicity*; D000975:Antioxidants / Q000494:pharmacology*; D002374:Catalase / Q000378:metabolism; D001467:Hordeum / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D008315:Malondialdehyde / Q000378:metabolism; D009580:Nitroblue Tetrazolium / Q000737:chemistry; D018384:Oxidative Stress / Q000187:drug effects*; D010544:Peroxidases / Q000378:metabolism; D018517:Plant Roots / Q000033:anatomy & histology / Q000187:drug effects / Q000254:growth & development; D050050:Protein Carbonylation / Q000187:drug effects; D011522:Protons / Q000009:adverse effects*; D017382:Reactive Oxygen Species / Q000378:metabolism; D036226:Seedlings / Q000033:anatomy & histology / Q000187:drug effects* / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D013997:Time Factors; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
chemical_list: D000975:Antioxidants; D011522:Protons; D017382:Reactive Oxygen Species; D009580:Nitroblue Tetrazolium; D008315:Malondialdehyde; D005680:gamma-Aminobutyric Acid; D000535:Aluminum; D010544:Peroxidases; D002374:Catalase; D013482:Superoxide Dismutase