The Role of YABBY Gene Family Members in Promoting Lamina Expansion

种子植物的侧生器官，如叶和花器官，由顶端分生组织的侧面形成。因此，它们之间存在着一种内在的位置关系：叶原基有一个靠近分生组织的近轴侧，和一个远离分生组织的远轴侧。外科和遗传学研究表明，一个信号，其来源是分生组织，需要诱导近轴的身份，在它的情况下，远轴的命运被默认收购。随后，不对称的近轴-远轴轴为适当的叶片生长提供了线索。最近确定了参与这一过程的几个关键参与者，并且已经表明这些植物特异性基因家族（III类HD-ZIPs，YABBYs和KANADI）的各种成员之间和内部的复杂关系可能占种子植物侧部器官形态变异的重要部分。III类HD-ZIP基因促进近轴命运，并在分生组织和侧生器官中表达。 相比之下，KANADI和YABBY基因促进远轴命运，并且它们的表达仅限于发育侧器官的远轴域。 因此，近轴和远轴因子在相互排斥的结构域中表达，并且这些结构域之间的相互作用是适当的叶片发育所必需的。 一些证据表明，YABBY基因的活性可能密切参与的发展lamina. This建议的总体目标是更好地了解YABBY功能解决的作用，YABBY基因家族成员在促进远轴细胞的命运，并在促进叶片的发展。 拟进行的实验应澄清我们的理解YABBY功能的促进远轴细胞的命运和叶片的发展。 从长远来看，操纵叶子等侧生器官的大小和形状的能力可能会提高许多作物物种的生产力。

Lateral organs of seed plants, such as leaves and floral organs, are formed from the flanks of apical meristems. Therefore, an inherent positional relationship exists between them: leaf primordia have an adaxial side adjacent to the meristem, and an abaxial one away from the meristem. Surgical and genetic studies suggest that a signal, whose source is the meristem, is required to induce adaxial identity, and in its absence, abaxial fates are acquired by default. Subsequently, the asymmetric adaxial-abaxial axis provides cues for proper lamina growth. Several key players involved in this process were identified recently, and it has been suggested that complex relationships between and within various members of these plant-specific gene families (class III HD-ZIPs, YABBYs and KANADIs) may account for a significant portion of the morphological variation in lateral organs of seed plants. The class III HD-ZIP genes promote adaxial fates and are expressed in the meristem and adaxially in lateral organs. In contrast, the KANADI and YABBY genes promote abaxial fates, and their expression is confined to the abaxial domains of developing lateral organs. Thus, the adaxial and abaxial factors are expressed in mutually exclusive domains, and interaction between these domains is required for proper leaf lamina development. Several lines of evidence suggest that YABBY gene activity may be intimately involved with the development of the lamina.The overall aim of this proposal is to better understand YABBY function addressing the role of YABBY gene family members in promoting abaxial cell fates and in promoting lamina development. The proposed experiments should clarify our understanding of YABBY function in the promotion of abaxial cell fates and the development of leaf lamina. In the long term, the ability to manipulate the size and shape of lateral organ, such as leaves, could lead to increased productivity of many crop species.