The molecular mechanism of vien patterning

我们的工作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了一个骨架和有效的运输途径。因此，我们的发现可能会影响旨在生产更多木材、抵御干旱胁迫或提高光合作用能力的植物改良。被确定为对静脉形成重要的因素主要涉及植物激素生长素的运输或反应。生长素是大量植物发育过程的基础，包括胚极性、根组织、枝根和叶的位置以及对重力和光的反应。在所有的过程中，生长素通过生长素流入和流出蛋白在细胞膜上的不对称位置进行定向运输是生长素功能的关键。尽管生长素外流的控制越来越为人所知，但对生长素内流的控制知之甚少。静脉模式似乎足够复杂，以至于对静脉模式突变的筛选揭示了生长素运输和响应中的新成分，这些额外的作用或效应太过微妙，在传统的筛选中无法检测到。因此，除了更好地了解血管形成之外，我们的工作还将揭示控制生长素在整个植物发育过程中定位和活性的分子机制。我们建议剖析由突变确定的四个基因--Autobahn(ABN)、FORKED1(FKD1)、Unhinged(UNH)和Grasy(GSY)的作用。ABN中突变的植物会产生高度无序的叶脉并改变叶片的位置。我们的数据表明，这些植物在生长素内流方面存在缺陷，因此代表了第一个将生长素内流与叶位置和叶脉模式联系起来的突变。我们计划进行实验，以找出ABN产生什么产物，以及它如何影响生长素内流。我们说，FKD1基因产物是一种带有一个结构域的蛋白质，它参与将生长素外流蛋白正确地定位到细胞膜上。我们将测试这一想法。最后，我们将鉴定和鉴定其突变表型在生长素运输或信号转导中的作用。

Our work strives to understand 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.  Thus, our findings may impact plant modifications designed to produce more wood, withstand drought stress, or improve photosynthetic capacity.  The factors identified as being important to vein formation are primarily involved in transport of or response to 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 influx and efflux proteins on cell membranes is critical to auxin function.  While control of auxin efflux is increasingly well understood, little is known about the control of auxin influx.  Vein pattern seems to be sufficiently complex that screens for vein pattern mutants reveal novel components in auxin transport and response, with either redundant roles or effects too subtle to be detected in classical screens.  Thus, beyond providing a better understanding of vascular formation, our work will reveal molecular mechanisms controlling auxin localization and activity throughout plant development. We propose to dissect the role of four genes - AUTOBAHN (ABN), FORKED1 (FKD1), UNHINGED (UNH) and GRASSY (GSY) - identified by mutation. Plants mutant in ABN make highly disordered veins and alter placement of leaves.  Our data suggest that these plants are defective in auxin influx, and thus represent the first mutation that links auxin influx to leaf position and vein pattern.  We plan experiments to find out what product ABN makes, and how it influences auxin influx.   The FKD1 gene product is a protein with a domain indicative of involvement in properly localizing the auxin efflux protein to the cell membrane.  We will test this idea.  Finally, we will identify and characterize both UNH and GSY whose mutant phenotypes suggest a role in auxin transport or signaling.