Collaborative Research: The Aquilegia Petal as a Model for the Elaboration and Evolution of Organ Shape

植物的身体是由一些重复产生的结构组成的，比如叶子和茎。然而，这些结构的形状在个体内部和不同物种之间以可预测的、一致的方式变化巨大。这种形状的变化是由细胞分裂和细胞形状的结合控制的，而细胞形状又必须由基因表达的变化控制。这项拟议的研究旨在确定复杂形状是如何在发育过程中产生的，以及控制这些过程的基因。因此，这项研究将解决生物如何实现其身体形状的基本问题，这对它们的生存至关重要。这项研究还将通过培养包括本科生、研究生和博士后在内的年轻科学家，并努力招募女性和代表性不足的少数民族，从而产生更广泛的影响。Aquilegia的花蜜刺是一种复杂的三维结构，是最近衍生的，在物种之间具有高度变异，因此可以作为研究复杂器官形状控制和进化的有力模型。花蜜刺的发育是通过早期的局部定向细胞分裂形成预先定型的刺杯，然后是一段高度各向异性的细胞伸长期，最终形成刺的长度和形状。在亲缘关系密切的水仙属（Aquilegia）中，骨刺长度和形状的变化是通过改变几个发育参数产生的：长度主要由细胞各向异性控制，而细胞各向异性又由细胞伸长的持续时间控制；曲率是由骨刺远端与近端间室的细胞伸长变化而产生的；在径向方向上，细胞的各向异性和细胞数量的变化可以控制细胞的周长。因此，了解Aquilegia刺的发育和进化将提供对侧枝器官发育的所有这些基本方面的见解，这可以为被子植物侧枝器官的进化提供新的视角。拟议的研究旨在整合来自发育遗传学，进化基因组学/遗传学和生物物理学领域的多条研究线。具体而言，该项目将阐明花瓣刺发育的基本遗传控制，探索激素信号和生物力学菌株在控制刺发育中的作用，使用基于qtl的方法识别参与刺形状多样化的基因，并使用比较基因组方法识别与花蜜刺起源相关的选择性扫描。

The body of a plant is made of just a few repeatedly produced structures, such as leaves and stems. However, these structures can vary tremendously in their shape both within an individual and between different species in predictable, consistent ways. This variation in shape is controlled by a combination of cell division and cell shape, which in turn must be controlled by variation in gene expression. The proposed research seeks to determine how complex shapes arise through development and the genes that control these processes. Thus this research will address the fundamental question of how organisms achieve the shapes of their bodies, which is critical to their survival. This research will also have broader impacts through the training of young scientists including undergraduates, graduate students and postdoctoral fellows with outreach efforts to recruit female and underrepresented minorities. The nectar spur of Aquilegia is a complex three-dimensional structure that is recently derived and highly variable among species and, thus, can serve as a powerful model for investigating the control and evolution of complex organ shape. Nectar spurs develop via an early phase of localized, oriented cell divisions that create the prepatterned spur cup, which is then followed by a period of highly anisotopic cell elongation that gives rise to the final length and shape of the spur. Among the closely related and interfertile species of Aquilegia, variation in spur length and shape is generated by changing several developmental parameters: length is primarily controlled by cell anisotropy, which is in turn controlled by the duration of cell elongation; curvature is generated by varying cell elongation between the distal vs. proximal compartments of the spur; and circumference is controlled both by changes in cell anisotropy and cell number in the radial orientation. Thus, understanding the development and evolution of Aquilegia spurs will provide insight into all of these fundamental aspects of lateral organ development, which can provide new perspectives on the evolution of lateral organs more broadly across the angiosperms. The proposed research seeks to integrate multiple lines of study drawn from the fields of developmental genetics, evolutionary genomics/genetics, and biophysics. Specifically, the project will elucidate the fundamental genetic control of petal spur development, explore the roles of hormonal signaling and biomechanical strain in controlling spur development, use QTL-based approaches to identify the genes involved in the diversification of spur shape and use comparative genomic approaches to identify selective sweeps associated with the origin of nectar spurs.