Credentials: Biochemistry Department
Position title: Seasonal control of flowering
Phone: (608) 265-2170
433 Babcock Dr
Madison, WI 53706
Plant Biology; Developmental Biology & Regenerative Medicine; Cellular & Molecular Metabolism
The major developmental change in the plant life cycle is the initiation of flowering. Many plant species have evolved the ability to regulate flowering in response to environmental variables such as changes in day-length or temperature. We have been studying how, at a molecular level, plants sense and respond to these environmental cues to initiate the transition to flowering. Our approach blends genetic analyses to identify genes involved in environmentally regulated flowering with studies of the biochemistry of how the gene products operate.
A summary of past work in Arabidopsis thaliana: We discovered a gene (FLC) that prevents flowering in Arabidopsis unless the plants have experienced the cold of winter. The FLC protein is a repressor that binds to the promoters of genes required for the flowering transition. Exposure to cold (through a process known as vernalization) enables flowering by triggering a stable epigenetic switch of the FLC gene to a repressed state. This epigenetic state of FLC is reset to an active state in the next generation.
Recently, we have shifted to studying the molecular basis of flowering in the model grass Brachypodium distachyon. Grasses are important components of many ecosystems on our planet and are also important crops (wheat, barley, rice, and corn are examples of grasses). Much of the environmental flowering responses in grasses evolved independently of those in Arabidopsis because it was only after the divergence of these the major lineages of flowering plants that continents drifted and climate changed such that a vernalization response was adaptive. We have identified several genes that are involved in flowering control in response to seasonal and developmental cues in Brachypodium. The homologs of these genes are not involved in flowering in Arabidopsis reinforcing the independent evolution of many aspects of flowering control in grasses versus the mustard family (Brassicaceae) which includes Arabidopsis. Our present goal is to further the understanding of how flowering in grasses is regulated at a molecular level.