ELONGATED UPPERMOST INTERNODE encodes a cytochrome P450 monooxygenase that epoxidizes gibberellins in a novel deactivation reaction in rice

Yongyou Zhu, Takahito Nomura, Yonghan Xu, Yingying Zhang, Yu Peng, Bizeng Mao, Atsushi Hanada, Haicheng Zhou, Renxiao Wang, Peijin Li, Xudong Zhu, Lewis N. Mander, Yuji Kamiya, Shinjiro Yamaguchi, Zuhua He

Research output: Contribution to journalArticlepeer-review

267 Citations (Scopus)

Abstract

The recessive tall rice (Oryza sativa) mutant elongated uppermost internode (eui) is morphologically normal until its final internode elongates drastically at the heading stage. The stage-specific developmental effect of the eui mutation has been used in the breeding of hybrid rice to improve the performance of heading in male sterile cultivars. We found that the eui mutant accumulated exceptionally large amounts of biologically active gibberellins (GAs) in the uppermost internode. Map-based cloning revealed that the Eui gene encodes a previously uncharacterized cytochrome P450 monooxygenase, CYP714D1. Using heterologous expression in yeast, we found that EUI catalyzed 16α,17-epoxidation of non-13-hydroxylated GAs. Consistent with the tall and dwarfed phenotypes of the eui mutant and Eui-overexpressing transgenic plants, respectively, 16α,17-epoxidation reduced the biological activity of GA4 in rice, demonstrating that EUi functions as a GA-deactivating enzyme. Expression of Eui appeared tightly regulated during plant development, in agreement with the stage-specific eui phenotypes. These results indicate the existence of an unrecognized pathway for GA deactivation by EUI during the growth of wild-type internodes. The identification of Eui as a GA catabolism gene provides additional evidence that the GA metabolism pathway is a useful target for increasing the agronomic value of crops.

Original languageEnglish
Pages (from-to)442-456
Number of pages15
JournalPlant Cell
Volume18
Issue number2
DOIs
Publication statusPublished - 2006 Feb
Externally publishedYes

ASJC Scopus subject areas

  • Plant Science
  • Cell Biology

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