| Abstract Detail
Integrative Plant Physiology Choi, Dongsu [1], Yang, Seung-Hwan [2]. Ethylene-induced stem growth is correlated with altered expression of the genes encoding gibberellin- and ABA- metabolism enzymes in the internode of deepwater rice. Ethylene and submergence enhance stem elongation in deepwater rice, at least in part, by reducing in the internode the endogenous abscisic acid (ABA) content and increasing the level of gibberellin A1 (GA1). We analyzed the expression pattern of genes encoding GA biosynthetic enzymes as a result of ethylene treatment to check the possible molecular basis for the observed increase in GA1 content. The expression of the OsGA20ox2 and OsGA20ox4 genes, which encode GA-20 oxidase, and of the OsGA3ox2 gene, which encodes the enzyme that converts GA20 to GA1, was upregulated by ethylene treatment. We cloned and characterized the CYP707A5 and CYP707A6 genes, which encode putative ABA 8’ hydroxylase, the enzyme that oxidizes ABA. Expression of CYP707A5 was upregulated significantly by ethylene treatment, whereas that of CYP707A6 was not altered. CYP707A5 also responds to stresses such as high salinity and mannitol treatment. This indicates that CYP707A5 may play a role in ABA catabolism during submergence- or ethylene-induced stem elongation in deepwater rice. We are evaluating further the significance of these results with respect to the molecular mechanisms regulating submergence- and ethylene-induced stem elongation of deepwater rice.
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1 - Kunsan National University, School of Science and Technology, 68 Miryong-dong, Gunsan, Jeon-buk, 573-701, Republic of Korea
2 - Michigan State University, Department of Forestry
Keywords:
deepwater rice
stem growth
gibberellin
ABA
ethylene.
Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P04010
Abstract ID:1208 |
