Understanding the molecular mechanism of vein formation in Arabidopsis

我们的研究致力于了解控制静脉形成的分子机制。维管系统是植物结构和功能的基础，为水分、光合作用产物、必需营养物质、病原体和信号化合物提供骨架和有效的运输途径。事实上，由于改善了向光合作用细胞的水分输送，叶脉密度是不同植物在进化过程中光合作用效率的关键预测因子。因此，我们的发现可能会为提高光合作用能力或抵御干旱胁迫的植物改良提供信息和支持。被确认为对脉络形成重要的因素主要涉及植物激素生长素的运输。生长素是许多植物发育过程的基础，包括胚胎的极性、根的组织、枝根和叶的位置以及对重力和光的反应。在所有的过程中，生长素通过不对称地放置在细胞膜上的生长素外排蛋白进行定向运输是生长素功能发挥的关键。静脉模式似乎足够复杂，以至于筛选静脉模式突变揭示了新的生长素运输成分，这些成分要么具有多余的作用，要么影响太微小，在传统的根或胚胎缺陷筛查中无法检测到。因此，除了提供对维管形成的更好的理解外，我们的工作还将揭示在植物发育过程中控制生长素定位和活性的分子机制。我们已经发现了两个基因，FORKED1和Unhinged，它们对生长素外流蛋白在发育细胞中的不对称放置非常重要。我们将通过确定这些基因的蛋白质产物在细胞中的作用位置，它们与哪些蛋白质形成复合体，以及它们的表达、定位和伙伴关系如何受到调控，来更准确地定义这些基因的蛋白质产物是如何工作的。此外，我们还将识别新的基因，这些基因对协调叶脉图案和叶形以及控制叶片内的叶脉密度非常重要。

Our research works towards understanding the molecular mechanisms controlling vein formation. The vascular system is fundamental to plant structure and function, providing a skeleton and efficient transport routes for water, photosynthates, essential nutrients, pathogens and signaling compounds. In fact, because of improved water delivery to photosynthesizing cells, the density of veins is a key predictor of photosynthetic efficiency within diverse plants through evolutionary time. Thus, our findings may inform and allow plant modifications designed to improve photosynthetic capacity or withstand drought stress. The factors identified as being important to vein formation are primarily involved in transport of the plant hormone, auxin. Auxin is fundamental to a huge number of plant developmental processes, including embryo polarity, root organization, placement of branch roots and leaves and response to gravity and light. In all processes directional auxin transport through asymmetric placement of auxin efflux proteins on cell membranes is critical to auxin function. Vein pattern seems to be sufficiently complex that screens for vein pattern mutants reveal novel auxin transport components with either redundant roles or effects too subtle to be detected in classical screens for root or embryonic defects. Thus, beyond providing a better understanding of vascular formation, our work will reveal molecular mechanisms controlling auxin localization and activity throughout plant development. We have found two genes, FORKED1 and UNHINGED that are important for asymmetric placement of auxin efflux proteins in developing cells. We will define more precisely how the protein products of these genes work though establishing where they act in the cell, what proteins they form complexes with and how their expression, localization and partnerships are regulated. As well, we will identify new genes important to coordinating vein pattern with leaf shape and controlling the density of veins within the leaf.