Research in my lab will focus on a fundamental question in biology; how do plants sense their environment and adapt? Because they are sessile, plants must use a wide range of sophisticated environmental signaling mechanisms to minimize stress so that they can thrive. Like other eukaryotes, plants can use their energy-producing organelles (i.e. mitochondria and chloroplasts) as such sensors. In response to a changing environment or stress, these organelles can emit ‘retrograde’ signals that alter gene expression and/or cell physiology. This kind of signaling is important in plants, fungi, and animals and impacts diverse cellular functions including photosynthesis, energy production/storage, stress responses, growth, cell death, ageing, and tumor progression. Although many retrograde signaling pathways are known to exist in plants and other organisms, the mechanisms they use are poorly understood.
I am particularly interested in understanding a newly discovered stress signaling pathway that allows plant cells to selectively degrade damaged chloroplasts. In response to light-induced reactive oxygen species, we have shown that chloroplast proteins can be modified by ubiquitination. This may “mark” a damaged chloroplast for recycling, which allows a cell to maintain a healthy population of photosynthetically active chloroplasts. By using a combination of genetics, molecular biology, and biochemistry, we are identifying the genes and proteins involved in this chloroplast quality control pathway. Then by working backwards, we can begin to understand how these signaling factors are used by different plants under stress conditions such as drought or extreme light and temperatures. It is our hope that by understanding this and other retrograde signaling pathways, there is great potential to be able to engineer crops with stress-tolerant chloroplasts and photosynthetic systems thereby improving crop quality and yield.