Compartment-specific gene regulatory networks controlling seed development

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One of the underlying mechanisms of development is through the localized expression of genes encoding transcription factors (TFs) at specific times and places. Identification of TF genes that are essential for growth and development of oilseed crops such as canola (Brassica napus) by conventional genetic approaches has been limiting. Understanding the transcriptional mechanisms that control seed development in the closely related model species Arabidopsis thaliana (Brassicaceae family) will very likely provide the insight necessary to solve this issue. Growth of oilseeds like canola and Arabidopsis relies on the coordinated development of the embryo, endosperm and seed coat. Unlike the embryo and the endosperm the seed coat has received little attention when it comes to understanding the mechanisms that underlie its function. For example, the function of the proximal seed coat, which comprises the chalazal proliferating tissue and chalazal seed coat is unknown. However, histological observations suggest a transport function due to transfer cell morphology. Further, the rapid differentiation of this tissue makes it an ideal candidate to study cell differentiation. The long term goal of my research program is to understand all aspects of seed coat development. I will focus my attention for the shorter term towards the proximal region which includes the chalazal proliferating tissue and the chalazal seed coat compartments. The specific objectives of my research program are 1. Examine the structure-function relationship of the chalazal proliferating tissue in Arabidopsis 2. Characterize proximal seed coat TFs essential for seed development in both Arabidopsis and canola, and 3. Identify and validate gene-regulatory networks operating within the proximal seed coat. In the short term, I will continue to use Arabidopsis to achieve these goals since it is a proven developmental and genetic model system before translating this knowledge into canola. Enhancing seed growth in a more directed compartment-specific manner should lead to an increase in seed yield and ultimately food production which remains a primary objective in modern Canadian agriculture.