Arabidopsis Gynoecium Development – Reproductive competence of flowering plants requires proper development of the carpel, which is the female reproductive organ of the plant. The meristematic regions along the margin of the developing carpel generate ovules that will later develop into seeds. These meristematic regions have been termed carpel margin meristems (CMMs) and are functionally analogous to the mammalian ovary and placenta. The CMMs provide an excellent system to study basic problems in developmental biology such as patterning, the regulation of cellular proliferation and the control of organ size and shape. Dr. Franks’ research program seeks to clarify basic mechanisms of organ size and shape regulation and understand relationships between patterning cues and cellular proliferation within the carpel. Current research focuses on (1) the elucidation of the transcriptional gene regulatory network that controls ovule initiation and meristematic competence in the carpel; 2) the identification and functional studies of novel genes that play a critical role in CMM development; 3) the application of fluorescent activated cell sorting (FACS) technology to isolate transcriptionally-distinct populations of carpel cell types.
Hybrid Seed Inviability and the Evolution of Endosperm Development in Mimulus – The endosperm is the starch- and/or protein-rich tissue within the seed. It is estimated that 67% of the calories of the human diet are derived from the endosperm of agricultural varieties (mostly grains). In addition to its agricultural importance, the study of embryo and endosperm development is of interest to both developmental biologists and evolutionary biologists. The parental conflict theory is an evolutionary theory that predicts that genes supporting endosperm and embryo development will be subject to imprinting and parent-of-origin effects. Furthermore, the rapid evolution of genes that function in the regulation of parental conflict has been proposed to act as a reproductive isolation mechanism and thus may support speciation events. In this collaboration with Dr. John Willis in the Dept. of Biology at Duke University, we are examining embryo and endosperm developmental defects resulting from incompatible inter-specific crosses between Mimulus species. We expect these studies will illuminate developmental, molecular and evolutionary mechanisms of reproductive isolation and speciation, as well as mechanisms of endosperm development.