Male reproductive processes in flowering plants occur in the anther. This organ is composed of several specialized tissues and cell types and is responsible for producing pollen grains that contain the sperm cells. Anther tissues form in an orderly pattern from cell lineages that are present within the floral meristem. These tissues differentiate from precursor cells that appear at specific locations, or territories, within the developing anther primordium. The molecular processes responsible for the specification of different anther cell types after primordium initiation are not known. Nor is it understood how gene sets that are expressed in specific anther cell types are activated coordinately during anther development. Experiments outlined in this proposal will utilize chimeric cytotoxic and anticytotoxic genes to address the role of cell/cell interaction processes in the specification of anther cell types. Other experiments will utilize molecular strategies to identify elements of the regulatory circuitry necessary to activate several non-homologous genes within one anther tissue, the tapetum. The significance of these experiments is that they should provide new insight into the communication processes required for the differentiation of anther cell types, provide entry into the processes required for the differentiation of anther cell types, provide entry into the molecular pathways responsible for the specification of these cell types, and generate new conceptual information on the mechanisms that control cell-specific gene expression during plant development.
