Functional Analyses of Initiation and Laminar Expansion of Plant Lateral Organs

植物由一系列重复的侧部器官节段组成，这些侧部器官节段由称为芽分生组织的小的形态发生组织丛发育而来。叶是一个基态的侧生器官;在花序和花的发育过程中，产生叶的发育机制重复和修改。因此，了解叶的发育是我们理解整个植物发育的核心。 以前的分子遗传学分析在不同的植物物种产生了可测试的模型，叶的启动和生长的机制。 此外，比较的方法是很重要的，更好地了解如何不同的叶形态演变，并可能在未来的农艺优势。 这项研究将利用隐性突变，影响启动和/或扩展的叶子。 实验将研究这些基因的表达模式和功能，有助于阐明更多关于叶的发育和形态进化。提出了三个具体目标。(1)玉米/拟南芥基因NARROW SHEATH（NS）/PRESSED FLOWER（PRS）对于从茎分生组织起始侧叶结构域是必需的。 玉米和拟南芥的叶是单叶，而番茄形成由许多小叶组成的复叶。 本研究拟从番茄中克隆NS/PRS基因，并通过分子遗传学分析确定该基因在番茄复叶发育过程中的功能。 (2)将用荧光标记的蛋白质和特异性抗体分析PRS积累和功能的发育时间和分生组织层特异性。 这些实验将研究PRS非细胞自主性的机制，其中PRS功能超出表达PRS的那些细胞和组织。 (3)RAGGEDSEEDLING 2基因将被确定，RGD 2在玉米发育过程中的表达分析将产生RGD 2在叶子的横向生长和扩展过程中如何发挥作用的模型。这些研究活动将与向格鲁吉亚的中学生介绍植物生物学研究的努力平行进行。

Plants are comprised of a series of repeated lateral organ segments that develop from small clumps of morphogenic tissue called shoot meristems. The leaf is a ground state lateral organ; the developmental mechanisms generating leaves are repeated and modified during development of inflorescences and flowers. Thus, an understanding of leaf development is central to our comprehension of overall plant development. Previous molecular genetic analyses in diverse plant species have generated testable models for mechanisms of leaf initiation and growth. In addition, comparative approaches are important for better understanding how diverse leaf morphologies have evolved, and may be utilized for agronomic advantage in the future. This research will exploit recessive mutations that affect the initiation and/or expansion of leaves. Experiments will investigate the expression patterns and functions of these genes, helping to elucidate more about the development and morphological evolution of leaves. Three specific aims are proposed. (1) The maize/Arabidopsis genes NARROW SHEATH (NS)/PRESSED FLOWER (PRS) are required for the initiation of lateral leaf domains from shoot meristems. Maize and Arabidopsis leaves are simple, whereas tomato forms compound leaves comprised of many leaflets. The NS/PRS gene will be cloned from tomato, and molecular-genetic analyses will determine the function of this gene during the development of compound tomato leaves. (2) The developmental timing and meristematic tissue layer-specificity of PRS accumulation and function will be analyzed with fluorescently tagged proteins and specific antibodies. These experiments will investigate mechanisms of PRS non-cell autonomy, wherein PRS functions beyond those cells and tissues in which PRS is expressed. (3) The RAGGEDSEEDLING2 gene will be identified and analyses of RGD2 expression during maize development will generate models for how RGD2 functions during the lateral growth and expansion of leaves.These research activities will be performed in parallel with efforts to introduce middle school aged students in Georgia to plant biological research.