Plant Cell SoftGenetics
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
QUICK SEARCH:   [advanced]


     

Plant Cell Advance Online Publication
Published on May 16, 2008; 10.1105/tpc.107.057455

This Article
Right arrow Full Text - TPC Advance Online Pub. (PDF)
Right arrow Supplemental Data
Right arrow All Versions of this Article:
20/5/1316    most recent
tpc.107.057455v1
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 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 Google Scholar
Google Scholar
Right arrow Articles by Yamada, T.
Right arrow Articles by Wakasa, K.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Yamada, T.
Right arrow Articles by Wakasa, K.
Agricola
Right arrow Articles by Yamada, T.
Right arrow Articles by Wakasa, K.

Received December 10, 2007
Returned for revision March 16, 2008
Accepted April 29, 2008

Mutation of a Rice Gene Encoding a Phenylalanine Biosynthetic Enzyme Results in Accumulation of Phenylalanine and Tryptophan

Tetsuya Yamada 1, Fumio Matsuda 2, Koji Kasai 2, Shuichi Fukuoka 3, Keisuke Kitamura 4, Yuzuru Tozawa 5, Hisashi Miyagawa 6, and Kyo Wakasa 7*

1 CREST, Japan Science and Technology Agency, Tokyo 103-0027, Japan; Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
2 CREST, Japan Science and Technology Agency, Tokyo 103-0027, Japan
3 QTL Genomics Research Center, National Institute of Agrobiological Sciences, Tsukuba 305-8602, Japan
4 Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
5 CREST, Japan Science and Technology Agency, Tokyo 103-0027, Japan; Cell-Free Science and Technology Research Center, Ehime University, Matsuyama 790-8577, Japan
6 CREST, Japan Science and Technology Agency, Tokyo 103-0027, Japan; Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
7 CREST, Japan Science and Technology Agency, Tokyo 103-0027, Japan; Department of Agriculture, Tokyo University of Agriculture, Atsugi 243-0034, Japan

* To whom correspondence should be addressed. E-mail: k3wakasa{at}nodai.ac.jp.

Two distinct biosynthetic pathways for Phe in plants have been proposed: conversion of prephenate to Phe via phenylpyruvate or arogenate. The reactions catalyzed by prephenate dehydratase (PDT) and arogenate dehydratase (ADT) contribute to these respective pathways. The Mtr1 mutant of rice (Oryza sativa) manifests accumulation of Phe, Trp, and several phenylpropanoids, suggesting a link between the synthesis of Phe and Trp. Here, we show that the Mtr1 mutant gene (mtr1-D) encodes a form of rice PDT with a point mutation in the putative allosteric regulatory region of the protein. Transformed callus lines expressing mtr1-D exhibited all the characteristics of Mtr1 callus tissue. Biochemical analysis revealed that rice PDT possesses both PDT and ADT activities, with a preference for arogenate as substrate, suggesting that it functions primarily as an ADT. The wild-type enzyme is feedback regulated by Phe, whereas the mutant enzyme showed a reduced feedback sensitivity, resulting in Phe accumulation. In addition, these observations indicate that rice PDT is critical for regulating the size of the Phe pool in plant cells. Feeding external Phe to wild-type callus tissue and seedlings resulted in Trp accumulation, demonstrating a connection between Phe accumulation and Trp pool size.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
ASPB Publications THE PLANT CELL PLANT PHYSIOLOGY
Copyright © 2008 by the American Society of Plant Biologists