Transcription Factors Regulating Compound Leaf Development in Tomato

通常，在高等植物中，叶的上部（近轴）部分在解剖学和生理学上不同于叶的底部（远轴）部分。 这种不对称性（ab-adaxiality）是建立在叶原基和拍摄顶端分生组织（SAM）的早期似乎提供了位置线索，这种不对称性的初步建立。 KNOX 1基因在维持SAM的不确定性和随后的芽发育中起着重要作用，而几个基因，如PHAN，PHAV，PHAB，REV，在几个物种中被认为是指定侧部器官的近轴和远轴域。据报道，PHAN是KNOX基因的负调控因子，并且PHAN和KNOX基因的表达结构域在形成单叶的叶尖中不重叠。然而，在番茄中，在SAM的中心检测到KNOX 1基因TKN 1和LeT 6以及PHAN的表达。该建议的目的是了解复叶发展的模式生物番茄（番茄）使用正向和反向遗传学的分子基础，然后看看在番茄中发现的发展原则是否适用于各种类型的复叶的独立进化起源。 初步数据表明，KNOX 1基因是导致多种物种复叶的发育级联的重要组成部分。 此外，PHAN表达的域和量调节小叶在不同复叶中的位置。 拟议的研究将利用一系列方法，包括分析KNOX 1相互作用基因中的发育突变，以及对来自简单和复叶物种的正向KNOX 1基因和PHAN进行启动子比较。 此外，转基因方法将在单叶和复叶物种之间交换启动子：报告基因融合，下调和上调KNOX 1相互作用蛋白和调节叶中离轴性的蛋白的表达，将用于彻底剖析番茄复叶发育。 这项研究的长期目标是最终将在番茄中学到的原理应用于理解进化背景下的叶发育。这项活动的更广泛影响包括对博士后研究员、研究生和大学生进行研究方法方面的培训。几名本科生已经在研究方面接受了培训，并在过去的资助期间共同撰写了论文，许多本科生来自少数民族。 这些活动将在本供资期内继续进行。

0316877SinhaGenerally, the upper (adaxial) part of the leaf is anatomically and physiologically different from the bottom (abaxial) part of the leaf in higher plants. This asymmetry (ab-adaxiality) is established early in the leaf primordium and the shoot apical meristem (SAM) seems to provide positional cues for the initial establishment of this asymmetry. The KNOX1 genes play an important role in maintaining indeterminacy in the SAM and in subsequent shoot development while several genes, like PHAN, PHAV, PHAB, REV, in several species are thought to specify the adaxial and abaxial domains of lateral organs. PHAN is reported to be a negative regulator of KNOX genes and the expression domains of PHAN and KNOX genes do not overlap in apices making simple leaves. However, in tomato expression of the KNOX1 genes TKN1 and LeT6 and PHAN is detected in the center of the SAM. This proposal aims to understand the molecular basis of compound leaf development in the model organism Lycopersicon esculentum (tomato) using both forward and reverse genetics and then to see if the developmental principles discovered in tomato are applicable to various types of compound leaves of independent evolutionary origins. Preliminary data suggests that the KNOX1 genes are an important part of the developmental cascade leading to compound leaves in a variety of species. Further, the domain and amount of PHAN expression regulates leaflet placement in diverse compound leaves. The proposed research will utilize a combination of methods involving analysis of developmental mutations in KNOX1 interacting genes and promoters comparisons for orthologous KNOX1 genes and PHAN from simple and compound leafed species. In addition transgenic approaches will exchange promoter:reporter gene fusions between simple and compound leafed species, and downregulate and upregulate expression of the KNOX1 interacting proteins and proteins that regulate ab-adaxiality in leaves will used to thoroughly dissect compound leaf development in tomato. The long-term goal of this research is to eventually apply the principles learnt in tomato to understanding leaf development in an evolutionary context. Broader impacts of this activity included the training of post-doctoral fellows, graduate students and undergraduates in research methodology. Several undergraduate students have been trained in research and have co-authored papers in the past funding period and many of the undergraduate students come from minority groups. These activities will be maintained in the current funding period.