EUI1, encoding a putative cytochrome P450 monooxygenase, regulates internode elongation by modulating gibberellin responses in rice
EUI1, encoding a putative cytochrome P450 monooxygenase, regulates internode elongation by modulating gibberellin responses in rice
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DOI：
10.1093/pcp/pci233
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发表时间：
2006-02-01
影响因子：
4.9
通讯作者：
Chu, CC
中科院分区：
文献类型：
--
作者：
Luo, AD;Qian, Q;Chu, CC
水稻节间伸长是决定水稻株高和产量的重要农艺性状之一。研究表明，节间的伸长是受遗传控制的，这一过程涉及多种因素。在这里，我们报告了一个细长的最高internode 1（eui 1）突变体，已被用于杂交水稻育种的详细特征。在eui 1 -2突变体中，最上部节间的细胞长度显著长于野生型的细胞长度，因此产生伸长的最上部节间。结果表明，突变体中活性赤霉素水平升高，而其响应赤霉素的生长与野生型相似，表明eui 1突变体中较高水平的赤霉素积累导致最上部节间异常伸长。因此，几个编码赤霉素生物合成酶的基因的表达水平被改变。我们克隆了EUI 1基因，它编码一个假定的细胞色素P450单加氧酶，通过图位克隆，发现EUI 1 I弱表达在大多数组织中，但优先在年轻的穗。为了证实其功能，用不同的EUI 1构建体进行转基因实验。EUI 1的过表达引起了赤霉素缺乏样表型，这可以通过补充赤霉素部分逆转。此外，除了赤霉素生物合成基因的表达水平的改变，SLR 1蛋白的积累被发现在过表达的转基因植物中，表明EUI 1的表达水平涉及赤霉素介导的SLR 1破坏和赤霉素生物合成的反馈调节。因此，我们认为EUI 1在赤霉素介导的水稻最上部节间细胞伸长调控中起负作用。
Elongation of rice internodes is one of the most important agronomic traits, which determines the plant height and underlies the grain yield. It has been shown that the elongation of internodes is under genetic control, and various factors are implicated in the process. Here, we report a detailed characterization of an elongated uppermost internode1 (eui1) mutant, which has been used in hybrid rice breeding. In the eui1-2 mutant, the cell lengths in the uppermost internodes are significantly longer than that of wild type and thus give rise to the elongated uppermost internode. It was found that the level of active gibberellin was elevated in the mutant, whereas its growth in response to gibberellin is similar to that of the wild type, suggesting that the higher level accumulation of gibberellin in the eui1 mutant causes the abnormal elongation of the uppermost internode. Consistently, the expression levels of several genes which encode gibberellin biosynthesis enzymes were altered. We cloned the EUI1 gene, which encodes a putative cytochrome P450 monooxygenase, by map-based cloning and found that EUI1I was weakly expressed in most tissues, but preferentially in young panicles. To confirm its function, transgenic experiments with different constructs of EUI1 were conducted. Overexpression of EUI1 gave rise to the gibberellin-deficient-like phenotypes, which could be partially reversed by supplementation with gibberellin. Furthermore, apart from the alteration of expression levels of the gibberellin biosynthesis genes, accumulation of SLR1 protein was found in the overexpressing transgenic plants, indicating that the expression level of EUI1 is implicated in both gibberellin-mediated SLR1 destruction and a feedback regulation in gibberellin biosynthesis. Therefore, we proposed that EUI1 plays a negative role in gibberellin-mediated regulation of cell elongation in the uppermost internode of rice.