The ovules of higher plants play a central role in plant reproduction. In addition, because ovules are the precursors to seeds, ovule development is a critical component of crop productivity. Ovule development includes processes which typify development in all multicellular organisms and can be used as a model for studying fundamental mechanisms regulating morphogenesis and tissue differentiation in all organisms. The PI has identified a set of genes regulating critical steps in ovule developmental through isolation ovule mutations isolated by positional cloning methods. These include HUELLENLOS (HLL) and SHORT INTEGUMENTS 2 (SIN2) - both of which are essential for formation or expansion of the integuments (the precursors of the seed coat), and TSO1 - which is necessary for normal coordination of directional expansion of integument cells. The isolated genes will serve as tools for analysis of patterns of gene expression and for formation of initial models of the biochemical mechanism regulating ovule development. Completion of the proposed research will significantly increase understanding of genetic and molecular control of plant reproductive development and of morphogenesis and histogenesis in general. The cloned genes will also enable further research on regulation and manipulation of these fundamental developmental processes.
