Gibberellin homeostasis and plant height control by EUI and a role for gibberellin in root gravity responses in rice
Gibberellin homeostasis and plant height control by EUI and a role for gibberellin in root gravity responses in rice
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DOI：
10.1038/cr.2008.28
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发表时间：
2008-03
期刊：
影响因子：
44.1
通讯作者：
Yingying Zhang;Yongyou Zhu;Yu Peng;Dawei Yan;Qun Li;Jianjun Wang;Linyou Wang;Zuhua He
中科院分区：
文献类型：
--
作者：
Yingying Zhang;Yongyou Zhu;Yu Peng;Dawei Yan;Qun Li;Jianjun Wang;Linyou Wang;Zuhua He
水稻eui(E Long ATed U PPERMOST I NTERNODE)基因编码一种细胞色素P450单加氧酶，使生物活性赤霉素(GAs)失活。在本研究中，我们研究了eui基因的控制表达及其在植物发育中的作用。我们发现外源GAs对Eui有不同程度的诱导，并且Eui启动子在维管束中的活性最高。Eui突变体在根冠淀粉粒发育过程中存在缺陷，并且过表达增强了淀粉粒的生成和重力响应，揭示了GA在根淀粉粒发育和重力响应中的作用。利用无胚半种子进行的实验表明，在没有外源GA的情况下，RAmy1A和GAmyb在Eui糊粉细胞中高度上调。此外，赤霉素生物合成基因GA3ox1和GA20ox2在Eui幼苗中下调，而GA2ox1上调。这些结果表明，EUI不仅在抽穗期的节间，而且在苗期、根和种子中也参与了GA的动态平衡。GA动态平衡失调影响了GA信号基因GID1(赤霉素不敏感矮秆1)、GID2和SLR1的表达。转eui基因的RNA干扰有效地增加了株高，改善了抽穗性能。相反，水稻GA生物合成基因GA3ox2和GA20ox2启动子下的Eui异源表达显著降低了株高。这些结果表明，eui基因的表达略有增加就能显著改变水稻的形态，这表明eui基因在水稻高产分子育种中的实际应用潜力。
The rice Eui (E LONGATED U PPERMOST I NTERNODE) gene encodes a cytochrome P450 monooxygenase that deactivates bioactive gibberellins (GAs). In this study, we investigated controlled expression of the Eui gene and its role in plant development. We found that Eui was differentially induced by exogenous GAs and that the Eui promoter had the highest activity in the vascular bundles. The eui mutant was defective in starch granule development in root caps and Eui overexpression enhanced starch granule generation and gravity responses, revealing a role for GA in root starch granule development and gravity responses. Experiments using embryoless half-seeds revealed that RAmy1A and GAmyb were highly upregulated in eui aleurone cells in the absence of exogenous GA. In addition, the GA biosynthesis genes GA3ox1 and GA20ox2 were downregulated and GA2ox1 was upregulated in eui seedlings. These results indicate that EUI is involved in GA homeostasis, not only in the internodes at the heading stage, but also in the seedling stage, roots and seeds. Disturbing GA homeostasis affected the expression of the GA signaling genes GID1 (GIBBERELLIN INSENSITIVE DWARF 1), GID2 and SLR1. Transgenic RNA interference of the Eui gene effectively increased plant height and improved heading performance. By contrast, the ectopic expression of Eui under the promoters of the rice GA biosynthesis genes GA3ox2 and GA20ox2 significantly reduced plant height. These results demonstrate that a slight increase in Eui expression could dramatically change rice morphology, indicating the practical application of the Eui gene in rice molecular breeding for a high yield potential.