Enhanced antioxidant enzymes are associated with reduced hydrogen peroxide in barley roots under saline stress.
Antioxidant enzymes are related to the resistance to various abiotic stresses including salinity. Barley is relatively tolerant to saline stress among crop plants, but little information is available on barley antioxidant enzymes under salinity stress. We investigated temporal and spatial responses of activities and isoform profiles of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), non-specific peroxidase (POX), and glutathione reductase (GR) to saline stress in barley seedlings treated with 200 mM NaCl for 0, 1, 2, 5 days, respectively. In the control plant, hydrogen peroxide content was about 2-fold higher in the root than in the shoot. Under saline stress, hydrogen peroxide content was decreased drastically by 70% at 2 d after NaCl treatment (DAT) in the root. In the leaf, however, the content was remained unchanged by 2 DAT and increased about 14 % at 5 DAT. In general, the activities of antioxidant enzymes were increased in the root and shoot under saline stress. But the increase was more significant and consistent in the root. The activities of SOD, CAT, APX, POX, and GR were increased significantly in the root within 1 DAT, and various elevated levels were maintained by 5 DAT. Among the antioxidant enzymes, CAT activity was increased the most drastically. The significant increase in the activities of SOD, CAT, APX, POX, and GR in the NaCl-stressed barley root was highly correlated with the increased expression of the constitutive isoforms as well as the induced ones. The hydrogen peroxide content in the root.
Kim
Sang Yong
SY
Division of Biological Resources Sciences, and Institute of Agricultural Science and Technology, Chonbuk Natl University, Chonju 561-756, Korea.
Lim
Jung-Hyun
JH
Park
Myoung Ryoul
MR
Kim
Young Jin
YJ
Park
Tae Il
TI
Seo
Yong Won
YW
Choi
Kyeong Gu
KG
Yun
Song Joong
SJ
D000975:Antioxidants / Q000378:metabolism*; D060387:Ascorbate Peroxidases; D002374:Catalase / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D001467:Hordeum / Q000187:drug effects / Q000201:enzymology*; D006861:Hydrogen Peroxide / Q000378:metabolism*; D010544:Peroxidases / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000201:enzymology; D012965:Sodium Chloride / Q000494:pharmacology*; D013482:Superoxide Dismutase / Q000378:metabolism
D000975:Antioxidants; D012965:Sodium Chloride; D006861:Hydrogen Peroxide; D010544:Peroxidases; D060387:Ascorbate Peroxidases; D002374:Catalase; D013482:Superoxide Dismutase; D005980:Glutathione Reductase