AtGA3ox2, a key gene responsible for bioactive gibberellin biosynthesis, is regulated during embryogenesis by LEAFY COTYLEDON2 and FUSCA3 in Arabidopsis
AtGA3ox2, a key gene responsible for bioactive gibberellin biosynthesis, is regulated during embryogenesis by LEAFY COTYLEDON2 and FUSCA3 in Arabidopsis
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DOI：
10.1104/pp.104.047266
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发表时间：
2004-11-01
期刊：
影响因子：
7.4
通讯作者：
Vachon, G
中科院分区：
文献类型：
--
作者：
Curaba, J;Moritz, T;Vachon, G
胚胎调节因子LEC 2（LEAFY COTYLEDON 2）和FUS 3（FUSCA 3）参与拟南芥种子发育的多个方面，包括抑制叶片性状和过早萌发以及激活种子贮藏蛋白基因。在这项研究中，我们表明赤霉素（GA）激素的生物合成受到LEC 2和FUS 3途径的调节。相对于野生型水平，lec 2和fus 3突变体的未成熟种子中的生物活性GAs的水平增加。此外，我们表明，形成异位毛状体细胞的lec 2和fus 3胚胎是一个GA依赖的过程，在真叶，这表明GA途径被误激活的胚胎突变体。接下来，我们证明了GA生物合成基因AtGA 3 ox 2，它编码的关键酶AtGA 3 ox 2，催化非活性的生物活性的气体的转换，异位激活的两个突变体的胚胎。有趣的是，B-葡萄糖醛酸酶报告基因表达和原位杂交都表明，FUS 3主要抑制胚轴表皮细胞中的AtGA 3 ox 2表达，这与萌发时的AtGA 3 ox 2模式不同。最后，我们表明，FUS 3蛋白的物理相互作用与两个RY元素（CATGCATG）存在于AtGA 3 ox 2启动子。这项工作表明，GA生物合成直接控制拟南芥胚胎发育过程中的胚胎调节。
Embryonic regulators LEC2 (LEAFY COTYLEDON2) and FUS3 (FUSCA3) are involved in multiple aspects of Arabidopsis (Arabidopsis thaliana) seed development, including repression of leaf traits and premature germination and activation of seed storage protein genes. In this study, we show that gibberellin (GA) hormone biosynthesis is regulated by LEC2 and FUS3 pathways. The level of bioactive GAs is increased in immature seeds of lec2 and fus3 mutants relative to wild-type level. In addition, we show that the formation of ectopic trichome cells on lec2 and fus3 embryos is a GA-dependent process as in true leaves, suggesting that the GA pathway is misactivated in embryonic mutants. We next demonstrate that the GA-biosynthesis gene AtGA3ox2, which encodes the key enzyme AtGA3ox2 that catalyzes the conversion of inactive to bioactive GAs, is ectopically activated in embryos of the two mutants. Interestingly, both B-glucuronidase reporter gene expression and in situ hybridization indicate that FUS3 represses AtGA3ox2 expression mainly in epidermal cells of embryo axis, which is distinct from AtGA3ox2 pattern at germination. Finally, we show that the FUS3 protein physically interacts with two RY elements (CATGCATG) present in the AtGA3ox2 promoter. This work suggests that GA biosynthesis is directly controlled by embryonic regulators during Arabidopsis embryonic development.