Molecular Analysis of Abscission Zone Development

脱落几乎是植物脱落器官的一种普遍现象。在生态和适应方面，它允许灵活地处理逆境、伤害和授粉失败。它适应果实和种子的传播和季节性休眠。从经济上讲，它在去叶、去花/去幼果和成熟果实收获方面变得重要。在某些农业情况下，最好是促进或减少叶片、花/幼果或成熟果实的脱落。脱落可分为三个阶段。第一，将发生脱落的区域的发育-离区(AZ)；第二，器官与植物的实际分离；第三，在离区的近端形成细胞保护层。尽管对发育完全的AZs细胞之间的细胞分离过程已经进行了很好的研究，但某些细胞作为离区分化的过程还不是很清楚。这项建议中描述的实验将研究番茄花梗上形成AZ的过程中涉及的分子和细胞机制。该计划的长期目标是建立一个可用于研究离区发育的基因调控和细胞生物学的模型系统。番茄是建立这样一个模式系统的理想系统。PI希望确定无连接基因在脱落过程中的作用，并将该基因的表达模式与嵌合植物离解区的发育联系起来。

Abscission is an almost universal phenomenon by which plants shed organs. In terms of ecology and adaptation, it allows flexibility in dealing with stresses, injuries, and failure of pollination. It accommodates fruit and seed dispersal and seasonal dormancy. Economically it becomes important in terms of leaf removal, flower/young fruit removal, and mature fruit harvest. There are agricultural situations where it would be desirable to either promote or reduce leaf, flower/young fruit or mature fruit abscission. Abscission can be divided into three stages. First, the development of a region where abscission will occur --- the abscission zone (AZ); second, the actual separation of the organ from the plant; and third, the formation of a protective layer of cells on the proximal end of the zone. Although the process of cell separation between cells of fully developed AZs has been well investigated, the process by which certain cells differentiate as an abscission zone is not well understood. Experiments described in this proposal will examine the molecular and cellular mechanisms involved in the process by which an AZ forms on tomato pedicels. The long term goals of this program are to establish a model system that can be utilized to study the gene regulation and cell biology of abscission zone development. Tomato is an ideal system with which to set up such a model system. The PI hopes to determine the role of the jointless gene in the abscission process and relate the pattern of expression of this gene with the development of abscission zones in chimeric plants.