Ethylene-induced Stem Growth of Deepwater Rice Is Correlated with Expression of Gibberellin- and Abscisic Acid-biosynthetic Genes

Ethylene decreases the content of endogenous abscisic acid (ABA) and increases the level of bioactive gibberellin A1 (GA1) in the submerged internodes of deepwater rice. During partial submergence, internodes of deepwater rice undergo rapid elongation as a result of ethylene accumulation in the inte...

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Bibliographic Details
Published in:Journal of plant biology = Singmul Hakhoe chi 2007-10, Vol.50 (5), p.595-599
Main Author: Choi, Dong-Su
Format: Article
Language:Korean
Subjects:
abscisic acid
deepwater rice
ethylene
gibberellin
stem elongation
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Summary:Ethylene decreases the content of endogenous abscisic acid (ABA) and increases the level of bioactive gibberellin A1 (GA1) in the submerged internodes of deepwater rice. During partial submergence, internodes of deepwater rice undergo rapid elongation as a result of ethylene accumulation in the internodal lacunae. In an in vitro experiment using stem sections from deepwater rice, treatment with 5 μL L-1 ethylene promoted stem growth by up to 3.2-fold times over air treatment. Expression patterns were analyzed for genes that encode GA- and ABA-biosynthesis enzymes to determine any possible molecular basis for the changes observed in GA1 and ABA contents as a result of ethylene action. 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 up-regulated, whereas that of three ABA-biosynthetic genes - OsNCED1, OsNCED2, and OsNCED5 - was down-regulated in the presence of ethylene. These results indicate that GA and ABA contribute equally to the submergence- or ethylene-induced stem elongation of deepwater rice via the coordinated and opposite regulation of biosynthesis.
ISSN:1226-9239
1867-0725