ELONGATED UPPERMOST INTERNODE encodes a cytochrome P450 monooxygenase that epoxidizes gibberellins in a novel deactivation reaction in rice
ELONGATED UPPERMOST INTERNODE encodes a cytochrome P450 monooxygenase that epoxidizes gibberellins in a novel deactivation reaction in rice
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DOI：
10.1105/tpc.105.038455
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发表时间：
2006-02-01
期刊：
影响因子：
11.6
通讯作者：
He, ZH
中科院分区：
文献类型：
--
作者：
Zhu, YY;Nomura, T;He, ZH
隐性高水稻（Oryza sativa）突变体伸长上节间（eui）在形态上是正常的，直到抽穗期最后的节间急剧伸长。eui突变的阶段特异性发育效应已被用于杂交水稻雄性不育品种的抽穗育种。我们发现eui突变体在最上面的节间积累了异常大量的生物活性赤霉素（GAs）。基于图谱的克隆显示，Eui基因编码一种以前未被发现的细胞色素P450单加氧酶CYP714D1。通过在酵母中的异源表达，我们发现EUI催化非13-羟基化GAs的16 α， 17-环氧化。与eui突变体和过表达eui的转基因植株的高大和矮化表型一致，16 α， 17-环氧化降低了水稻中GA(4)的生物活性，表明eui具有GA失活酶的功能。Eui的表达在植物发育过程中受到严格调控，这与Eui的阶段特异性表型一致。这些结果表明，在野生型节间的生长过程中，存在一种未被识别的途径，可以通过EUI使GA失活。Eui作为GA分解代谢基因的鉴定进一步证明了GA代谢途径是提高作物农艺价值的有用靶点。
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 16 alpha, 17-epoxidation of non-13-hydroxylated GAs. Consistent with the tall and dwarfed phenotypes of the eui mutant and Eui-overexpressing transgenic plants, respectively, 16 alpha, 17-epoxidation reduced the biological activity of GA(4) 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.