Molecular mechanisms of light-regulated hypocotyl elongation

植物的形态发生在很大程度上取决于光照条件。植物的这种反应，通常被称为形态发生，主要由红光/远红光感光体光敏色素和蓝光感光体隐花色素介导。在本研究中，我们调查了这些反应的光感知网站。为此，我们采用了光响应启动子/增强子陷阱线，以及在某些组织/器官中表达光敏色素的转基因植物。同时，我们还对EID 1/SBL 1蛋白进行了分子生物学分析。首先，我们筛选了启动子/增强子诱捕株系，这些株系表现出光依赖性的报告基因GUS表达，对这些株系的分析表明，植物激素生长素参与了光形态建成反应。然后，我们建立了转基因株系，其中phyB-GFP在幼苗的某些部位表达。这些植物的生理分析表明，下胚轴的伸长主要由子叶中的phyB和其次由维管束中的phyB调节。我们进一步发现phyB的后一种功能依赖于cry 1。我们也试图鉴定与EID 1/SBL 1蛋白相互作用的因子，但没有成功。此外，我们还发现phyB的C-末端结构域与phyB在细胞核中的信号转导活性有关

Plants' morphogenesis depends very much on light conditions. Such responses of plants, often referred to as phomorphogenesis, are mediated mainly by a red/far-red light photoreceptor, phytochrome, and a blue light photoreceptor, cryptochrome. In the present study, we investigated photoperceptive sites of these responses. For this purpose, we employed light-responsive promoter/enhancer trap lines as well as transgenic plants that express phytochrome in certain tissues/organs. At the same time, we analyzed EID1/SBL1 protein by molecular biological techniques. Furthermore, a structure/function study of phytochrome was conductedFirst, we screened for promoter/enhancer trap lines that exhibited light-dependent expression of the reporter gene, GUS.Analysis of such lines suggested that a plant hormone, auxin, is involved in the photomorphogenic responses. We then established transgenic lines in which phyB-GFP was expressed in certain parts of the, seedling. Physiological analysis of such plants indicated that hypocotyl elongation is regulated primarily by phyB in cotyledons and secondarily by phyB in vascular bundle. We further found that the latter function of phyB depends on cry1, We have also tried to identify, factors interacting with EID1/SBLl protein but failed. In addition, we have shown that the C-terminal domain of phyB is dispensable for the signal transduction activity of phyB in the nucleus