Ph.D., Yale University, 1981
M.S., Yale University, 1977
B.A., College of Wooster, 1974
Dr. Poethig's research interests:
Plants change as they develop. Some of these changes occur gradually over a long period of time, whereas others occur quickly, often resulting in major changes in shoot morphology. This latter phenomenon is termed phase change, and is the primary focus of our research. We are particularly interested in the juvenile-to-adult transition, also known as vegetative phase change. This transition precedes flowering, and is characterized by changes in shoot architecture and patterns of cellular differentiation, and by changes in a variety of physiological processes such as photosynthesis. Vegetative phase change is promoted by a group of plant-specific transcription factors (SBP/SPL proteins), whose expression is repressed during the juvenile phase by the miRNAs, miR156 and miR157. Vegetative phase change occurs when the levels of miR156/miR157 decline, leading to an increase in the abundance of SBP/SPL proteins. We are studying how the temporal expression pattern of miR156/miR157 is regulated and how these miRNAs operate to regulate the expression of SBP/SPL genes in natural accessions of Arabidopsis. We are also interested in the relationship between vegetative phase change and reproductive competence.
In addition to our work on Arabidopsis, we have conducted studies on the adaptive significance and evolution of vegetative phase change in Acacias and related tree species. Some species of Acacia (now Vachellia) in both Central America and Africa have developed close a mutualistic relationship with ants, and we are interested in how the timing of vegetative phase change in these species has evolved to facilitate this relationship. We are also studying the molecular basis for the evolution of species of Acacia in Australia that remain permanently in the juvenile phase.
A final area of interest is the development of genetic tools for Arabidopsis thaliana. We have produced a set of transgenic lines (Traffic Lines) that significantly increase the speed and decrease the cost of many common tasks in genetic analysis. We are currently developing Traffic lines that will allow investigators to monitor the segregation of 1 mB segments across the entire genome, and identify recombination events within these regions.