Aleel K. Grennan (Kat)
Dr. Aleel K. Grennan
Assistant to the Editor-in-Chief,
Plant Physiology
University of Illinois
1201 W Gregory Dr
Urbana, IL 61801 USA
agrennan@uiuc.edu
My primary responsibility in the Ort Lab is as Assistant to the Editor-in-Chief for Plant Physiology but I also have an independent research project and am an a lecturer for IB102 "Plants, People and the Environment" in the spring semester. A major part of my appointment is writing the Plant Physiology feature article
"High Impact". High Impact is a review of a highly cited Plant Physiology article that discusses the impact the article has had on research. To do this, I select an article published 24 to 30 months from the projected print date and follow how the information in the article has been used by other researchers to support a data collected in their own study, lay down a scaffolding for new research, or provide a 'missing piece' to a puzzle.
My research interest is on the regulation of senescence and is currently focused on the regulation of pheophorbide a oxygenase (PaO), the enzyme responsible for the opening of the porphyrin macrocycle ("
Green Seed Problem"). During leaf senescence, as well in seed maturation, the photosynthetic components of the chloroplast are degraded in a coordinated process that includes the enzymatic breakdown of chlorophyll into colorless catabolites. However, this process can be interrupted by environmental factors such as low temperature exposure. While this is generally not a problem for many plants, in an agricultural setting, it can lead to a decrease in product value such as canola oil. If canola seeds are exposed to freezing temperatures early in development, normal chlorophyll degradation is disrupted resulting in mature seeds that retain chlorophyll, greatly devaluing the resulting oil. We have shown that freezing interferes with the later phases of canola seed development when chlorophyll is supposed to be cleared from the seed. The step that is affected is the opening of the porphyrin macrocycle, catalyzed by PaO. This study also demonstrated a change in the phosphorylation state of PaO during seed development, suggesting a regulatory role. I am using site-directed mutagenesis to looking further into the role of phosphorylation in the regulation of PaO as well as possible interacting proteins.
