Wi, Soo Jin , Park, Ky Young .
Regulatory effects of ethylene and polyamines on the gene expression of antioxidative enzymes in response to oxidative stress with H2O2 treatment.
The biosynthetic pathway of ethylene which is responsible for senescence and stress response has a same precursor, SAM, with polyamine biosynthesis, being contrary to each other for senescence and stress resistance in plants. We observed the higher resistance in transgenic tobacco plants which were manipulated for decrease in ethylene production and increase in polyamines accumulation. It was showed that no difference in the gene expression of the antioxidant enzymes (APX, GR, GST and Mn-SOD) among wild-type and ethylene-inhibited transgenic plants (CAS-AS, CAO-AS) without any stress. However, the transcripts of APX, Mn-SOD, and GST were more expressed in polyamine-increased transgenic plants than wild-type. The transcripts of APX, Mn-SOD and GST genes were induced significantly higher in the ethylene-inhibited transgenic plants after oxidative treatment with H2O2, which is known as a signal molecule of external stresses. Because H2O2 treatment induced ethylene production after 3h, we want to investigate whether the oxidative response with H2O2 treatment might be mediated by ethylene. Therefore, we determined the effects of precursor (ACC) or inhibitor (AVG) for ethylene biosynthesis on gene expression of antioxidative enzymes in wild-type plants. AVG treatment induced the higher expression of APX, Mn-SOD and GR gene, but ACC treatment did not rather changed those gene expression. GST and CAT transcripts were increased by spermidine treatment. It was suggested that the resistance against oxidative stress might be induced by the higher extent of gene expression for several specific antioxidative enzymes with the manner of ethylene-independent and polyamine-dependent. On the contrary, ethylene production might perhaps function as a negative regulator to stress resistance.
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1 - Sunchon National University, Korea Basic Science Institute, Sunchon Branch,, 315 Maegok-Dong, Sunchon, Chonnam, 540-742, Korea
2 - Sunchon National University, Department of Biology
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM