Molecular Genetic Analysis of Shoot Apical Meristem Development in Arabidopsis Thaliana

巴顿9724163 被子植物茎顶端分生组织（SAM）在植物茎的发育过程中起着重要作用，它决定了植物地上部分几乎所有的结构。SAM同时具有两个目的：它既作为模式形成的位点，又作为多能干细胞或初始细胞的来源。因此，SAM使用来自SAM中心的新细胞以重复和可预测的模式产生芽、叶和茎的基本亚基。该项目的长期目标是了解SAM如何形成植物的分子基础。 通过分离完全缺乏SAM或在SAM发育的某些方面有缺陷的突变体，有可能鉴定在SAM功能中独特重要的基因。其中之一是SHOOTMERISTEMLESS（STM）基因，这是一个含有同源结构域的基因，在模式植物拟南芥中SAM的形成和功能是必需的。STM作用于SAM的外围，形成器官间的分隔，在植物体的形成中起重要作用。我们将通过在SAM的外围特异性表达STM基因产物来测试这一概念，并询问这是否可以挽救stm突变体中子叶分离的缺陷。这个实验也将使我们能够测量STM在SAM中自主作用的程度。 也将研究SAM发育中的其他缺陷突变体。将使用外周区特异性报告基因构建体来确定几种被认为在中心区具有缺陷的突变体是否错误表达该构建体。PINHEAD基因是SAM中位置信息正确运作所需的基因，将被克隆以了解位置信息如何在SAM中发挥作用-这一过程几乎一无所知。 最后，异常突变体表明，存在一个积极的相互作用之间的近轴侧的叶片和SAM的形成。我们将通过分离不产生近轴叶结构域的突变体并询问它们是否可以形成腋生和初生SAM来测试这一假设。我们还将研究一个“过度”adaxialized突变体抑制突变体的SAM形成缺陷的表型的能力。

Barton 9724163 The shoot apical meristem (SAM) plays a central role in angiosperm shoot development giving rise to nearly all of the above-ground structures of the plant. The SAM simultaneously serves two purposes: it acts both as a site of pattern formation and as a source of pluripotent stem cells or initial cells. Thus, the SAM produces the basic subunits of the shoot, leaves and stem, in repeated and predictable patterns, using new cells derived from the center of the SAM. The long term goal of this project is to understand the molecular basis for how a SAM makes a plant. By isolating mutants that either entirely lack a SAM or are defective in some aspect of SAM development, it is possible to identify genes that are uniquely important in SAM function. One of these is the SHOOTMERISTEMLESS (STM) gene, a homeodomain-containing gene that is required for SAM formation and function in the model plant Arabidopsis. The STM appears to act in the periphery of the SAM to form the separations between organs, and in doing so, may play an important role in the shaping of the plant body. We will test this notion by specifically expressing the STM gene product in the periphery of the SAM and asking whether this can rescue the defect in cotyledon separation in stm mutants. This experiment will also allow us to gauge the degree to which STM acts cell autonomously within the SAM. Other mutants defective in SAM development will be studied as well. A Peripheral Zone specific reporter construct will be used to determine if several mutants suggested to have defects in the Central Zone misexpress this construct. The PINHEAD gene, a gene required for the correct functioning of positional information in the SAM, will be cloned to find out how positional information works in the SAM - a process about which almost nothing is known. Finally, the Adnormal mutant has suggested the existence of a positive interaction between the adaxial side of the leaf and SAM formation. We will test this hypothesis by i solating mutants that do not make an adaxial leaf domain and asking whether they can form axillary and primary SAMs. We will also investigate the ability of an "overly" adaxialized mutant to suppress the phenotypes of mutants defective in SAM formation.