Jang, Su Jin , Park, Ky Young , An, Gynheung .
Putrescine, spermidine, and spermine induced more resistance than cadaverine against abiotic stresses in Rice (Oryza sativa L.).
We screened oxidative stress-resistant mutant lines against H2O2 treatment in T-DNA insertion library of rice (Oryza sativa L.). Several oxidative stress-resistant mutant lines were successfully isolated and it was found that the genes such as putative endo-1,4-beta-glucanase, putative regulatory subunit of protein phosphatase, UV-B and ozone similarly regulated protein, putative peroxisomal Ca-dependent solute carrier, ferredoxin-dependent glutamate synthase, and several unknown genes were responsible for antioxidative response. We choose the rice mutant line of lysine decarboxylase for further study of antioxidative mechanism in plants. In this mutant line defected in lysine biosynthetic domain, the more accumulation of other polyamines, putrescine, spermidine, and spermine, under oxidative stress conditions were accompanied with more resistance in the aspects of chlorosis of leaves after treatment with H2O2 than in wild-type rice. Because reactive oxygen species (ROS) are generally damaging to essential cellular components, plants have evolved various ROS scavenging mechanisms. Even though the oxidative resistance in this knock-out mutant, the activities of ROS scavenging enzymes, catalase and cytosolic APX, were not changed. The production of H2O2 measured with DCFH-DA using confocal microscopy showed significantly lower level after both treatments of salt and acidic stress in knock-out mutants than wild-type rice. Therefore, it might be suggested that increases in cellular polyamines levels were responsible directly for the resistance against abiotic stresses such as salt and acid by acting as free radical scavenger with independence of antioxidative enzymes. But, we could not rule out the involvement of other antioxidative enzymes in this mutant.
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1 - Sunchon National University, Biology, 315 Maegok, Sunchon, Chonnam, 540-742, Korea
2 - Sunchon National University, Biology
3 - Pohang University of Science and Technology, National Research Laboratory of Plant Functional Genomics, Division of Molecular and Life Sciences
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM