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、光合作用、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效率的关键预测指标。因此，我们的发现可能为植物改良提供信息，以提高光合能力或抵御干旱胁迫。被认为对静脉形成很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，包括胚胎极性，根组织，分枝根和叶的位置以及对重力和光的响应。在所有过程中，生长素通过不对称放置在细胞膜上的生长素外排蛋白的定向运输对生长素的功能至关重要。静脉模式似乎非常复杂，静脉模式突变体的筛选揭示了新的生长素运输成分，这些成分要么具有冗余的作用，要么作用太微妙，无法在传统的根或胚胎缺陷筛选中检测到。因此，除了更好地理解维管形成，我们的工作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unched，这两个基因对于生长素外排蛋白在发育细胞中的不对称放置很重要。我们将更精确地定义这些基因的蛋白质产物是如何工作的，通过确定它们在细胞中的作用，它们与什么蛋白质形成复合物，以及它们的表达，定位和伙伴关系是如何被调节的。此外，我们还将发现对叶脉模式与叶片形状协调和叶脉密度控制具有重要意义的新基因。

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.