| The steps involved in ovule development represent essentially all of the types of morphogenic events of plant development, including differential cell division and expansion, signaling between various structures (e.g., inner integument and nucellus), and cell and tissue differentiation (e.g., vascular tissue vs. megaspore mother cell). This representation of general plant development, along with relatively simple architecture, potentially makes ovules an excellent model system for plant development. Additionally, ovule development is a critical late aspect of floral development that holds great importance for obvious reproductive and economical reasons.; In an effort to help develop this model system, I proposed for my dissertation to examine the genetic events involved in the early stages of ovule development. Specifically, I examined a series of female-sterile Arabidopsis mutants which were defective in ovule development, using such tools as scanning electron microscopy, confocal laser scanning microscopy, and double mutant analysis. Using this data I, with the help of many others, have constructed a preliminary model for the genetic control of ovule development in Arabidopsis. To further refine this model, I chose to concentrate on those genes involved in the earliest stages of ovule development: HUELLENLOS, and AINTEGUMENTA. Using positional cloning methods, I have localized HUELLENLOS to a small region of physical DNA. The isolation of the nucleic acid sequence will allow us to examine the underlying molecular mechanisms of the gene function, helping to further refine the model. |
