Mechanistic links between phytochrome signaling and chloroplast differentiation

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。PI：Meng Chen，Ph.D.Proposal Number：IOS-0923722 Title：Mechanism links between phytochrome signaling and chloroplast differentiation叶绿体分化，或植物如何在发芽后变绿色，对于建立光合质体使植物进行光合作用至关重要。 因此，它是光依赖植物发育过程中的一个重要过程。 虽然众所周知，叶绿体分化主要是由红色和远红色光感受器光敏色素控制，但对光敏色素启动这一过程的分子机制知之甚少。最近，研究人员在模式植物拟南芥中发现了光敏色素信号传导的一种新的重要成分HEMERA（HMR）。 有趣的是，HMR是迄今为止发现的第一个光敏色素信号组分，也是叶绿体分化所需的。HMR在陆地植物中编码高度保守的蛋白质，并且先前被证明与质体转录机制相关。 然而，研究人员的初步证据表明，HMR应该定位于细胞核。 作为该项目的一部分进行的研究旨在解决这一困境，通过确定HMR的亚细胞定位，并使用遗传学，生物化学和细胞生物学方法的组合来定义其定位信号。 这项研究有望揭示光敏色素信号传导与叶绿体分化启动之间的新机制。 叶绿体分化的分子机制的阐明将有助于我们的核和细胞器基因组如何协调其响应环境线索的基础知识，也将在提高农业产量的深刻影响。 此外，拟议的项目将提供优秀的培训，在分子遗传学的方法，博士后研究员，研究生和本科生。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).PI: Meng Chen, Ph.D.Proposal Number: IOS-0923722Title: Mechanistic links between phytochrome signaling and chloroplast differentiationChloroplast differentiation, or how plants turn green after germination, is critical to the establishment of photosynthetic plastids that enable plant to undergo photosynthesis. Thus, it is an essential process during light-dependent plant development. Although it is well known that chloroplast differentiation is controlled mainly by the red and far-red photoreceptor phytochromes, little is known about the molecular mechanisms by which phytochromes initiate this process. Recently, the investigators identified a novel and essential component for phytochrome signaling, HEMERA (HMR), in the model plant species Arabidopsis. Interestingly, HMR is the first phytochrome signaling component discovered so far that is also required for chloroplast differentiation. HMR encodes a highly conserved protein in land plants, and was previously shown to be associated with plastidic transcriptional machinery. However, preliminary evidence from the investigators suggests that HMR should be localized in the nucleus. The research undertaken as part of this project aims to solve this dilemma, by determining the subcellular localization of HMR and to define its localization signals using a combination of genetics, biochemical, and cell biological approaches. The proposed research is likely to unravel novel mechanisms linking phytochrome signaling and the initiation of chloroplast differentiation. The elucidation of molecular mechanisms for chloroplast differentiation will contribute significantly to our basic knowledge of how nuclear and organellar genomes coordinate their responses to environmental cues, and will also have deep implications in improving yield in agriculture. In addition, the proposed projects will provide excellent training in molecular genetic approaches for postdoctoral fellows, graduate students, and undergraduate students.