Female Gametophyte Development in Vascular Plants
Research in our laboratory centers on a key step in sexual plant reproduction, the formation of the female gametes. We study the molecular and genetic basis controlling ovule and megagametophyte development which ultimately leads to the production of the female reproductive cells. These are derived from the haploid multicellular gametophyte harbored within the ovule. Although the seven cells of the megagametophyte are of clonal origin, they develop along four alternative developmental pathways. The molecular and genetic basis controlling this important process is unknown. The highly polar nature of the female gametophtye, its small number of distinct cell types and its closely coordinated development with surrounding tissues of the ovule make it an ideal system to study fundamental aspects of plant development. The goal of our research is to investigate the role of positional information, cell lineage and cell-cell communication in plant morphogenesis and cellular differentiation.
To identify genes involved in this process we use enhancer detection, an approach that allows the identification of genes based on their pattern of expression. We have identified a large number of genes that are expressed in individual cells of the female gametophyte and are likely to be involved in their specification and differentiation. Others show a highly restricted and polar expression in the ovule illustrating regional gene expression and the importance of positional information for plant development. We are characterizing several genes and mutants involved in megagametogenesis. One of these is of particular interest because it has a dramatic effect on the subsequent generation and, thus, displays a maternal effect phenotype. A better understanding of the molecular mechanisms controlling megagametogenesis will not only provide important insights into fundamental concepts in plant development but also provide tools for the manipulation of the reproductive system. We are particularly interested in applying our findings to the engineering of apomixis, an asexual form of reproduction through seeds. The introduction of apomixis into sexual crops would have revolutionary implications for plant breeding and agriculture, allowing for the immediate fixation of any desired genotype and its indefinite clonal propagation.