Plant Physiol.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
 QUICK SEARCH:   [advanced]


     


This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via ISI Web of Science (54)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Shimada, Y.
Right arrow Articles by Yoshida, S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Shimada, Y.
Right arrow Articles by Yoshida, S.
Agricola
Right arrow Articles by Shimada, Y.
Right arrow Articles by Yoshida, S.

Plant Physiol, January 2003, Vol. 131, pp. 287-297

Organ-Specific Expression of Brassinosteroid-Biosynthetic Genes and Distribution of Endogenous Brassinosteroids in Arabidopsis

Yukihisa Shimada,* Hideki Goda, Ayako Nakamura, Suguru Takatsuto, Shozo Fujioka, and Shigeo Yoshida

RIKEN, Wako-shi, Saitama 351-0198, Japan (Y.S., H.G., A.N., S.F., S.Y.); Department of Chemistry, Joetsu University of Education, Joetsu-shi, Niigata 943-8512, Japan (S.T.); and Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan (A.N.)

Brassinosteroids (BRs) are steroidal plant hormones that are essential for growth and development. There is only limited information on where BRs are synthesized and used. We studied the organ specificity of BR biosynthesis in Arabidopsis, using two different approaches: We analyzed the expression of BR-related genes using real-time quantitative reverse transcriptase-polymerase chain reaction, and analyzed endogenous BRs using gas chromatography-mass spectrometry. Before starting this study, we cloned the second BR-6-oxidase (BR6ox2) gene from Arabidopsis and found that the encoded enzyme has the same substrate specificity as the enzyme encoded by the previously isolated 6-oxidase gene (BR6ox1) of Arabidopsis. Endogenous BRs and the expression of BR-related genes were detected in all organs tested. The highest level of endogenous BRs and the highest expression of the BR6ox1, BR6ox2, and DWF4 genes were observed in apical shoots, which contain actively developing tissues. These genes are important in BR biosynthesis because they encode the rate-limiting or farthest downstream enzyme in the BR biosynthesis pathway. The second highest level of endogenous BRs and expression of BR6ox1 and DWF4 were observed in siliques, which contains actively developing embryos and seeds. These findings indicate that BRs are synthesized in all organs tested, but are most actively synthesized in young, actively developing organs. In contrast, synthesis was limited in mature organs. Our observations are consistent with the idea that BRs function as the growth-promoting hormone in plants.


* Corresponding author; e-mail shimada{at}postman.riken.go.jp; fax 81-48-462-4674.

© 2003 American Society of Plant Biologists






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
ASPB Publications PLANT PHYSIOLOGY THE PLANT CELL
Copyright © 2003 by the American Society of Plant Biologists