Paul F. South
B.A.: Biology, Ursuline College, Pepper Pike, Ohio, 2004
Ph.D.: Department of Biochemistry, Purdue University, West Lafayette, Indiana, 2012
Post-Doc: Research Molecular Biologist, United States Department of Agriculture, Agriculture Research Service, Urbana, Illinois 2019
Office: A112 Life Sciences Annex
Lab: A124 Life Sciences Annex
Lab Phone: 225-578-2607
Area of Interest: Plant physiology and synthetic biology
Worldwide nearly 1 billion people are affected by hunger every day. As human population increases, traditional methods of crop improvement have become less effective in adapting and improving agricultural production. Essential to life on earth, photosynthesis is a fundamental process sensitive to environmental stresses. One factor limiting photosynthetic efficiency in C3 plants is photorespiration. Photorespiration is a multi-organellar process in plants to metabolize glycolate formed when Rubisco oxygenates rather than carboxylates ribulose-1,5-bisphosphate. Depending on growing temperatures photorespiration can reduce yields by 20-50% in crops such as wheat, rice, and soybeans. My long-term research goals focus on understanding photosynthetic and photorespiratory metabolism and use synthetic biology tools to understand gene regulation, the role of transport proteins and to use synthetic biology to improve crop productivity and quality.
Regulation of photorespiration during abiotic stress. Under elevated temperatures rates of photorespiration increase. What is not fully understood is how photorespiration is regulated and how photorespiration is involved in response to environmental perturbations at the genetic, epigenetic and metabolic level. When plants are exposed to elevated temperature in field settings expression of photorespiration genes increase in transcript likely in response to increased demand on the photorespiratory pathway. To determine how the photorespiration pathway is affected by both acute and chronic elevated temperature I look to observe changes in gene expression and how that may be coupled to changes in epigenetic patterning of photorespiratory genes.
Membrane transport in photorespiration. Photorespiration is a metabolic pathway that encompasses enzymes in the chloroplast, cytosol, peroxisome, and mitochondria. Flux through each of these compartments is essential for function of the photorespiratory pathway. The soluble enzymes involved in photorespiration have been studied for several decades but only 3 of the 28 possible transport steps involved in photorespiration are known at the genetic level. My previous work has identified BASS6 as a glycolate transporter in the chloroplast balancing the stoichiometry of the first and final transport steps involved in photorespiratory metabolism. Using a sensitive fluorescent screen method that identified BASS6 as a photorespiratory transporter I am currently examining other putative membrane proteins of unknown function that when no longer expressed cause a negative phenotype under photorespiration stress.
Crop improvement strategies using synthetic biology. Since the green revolution our understanding and knowledge of plant physiology has increased exponentially and offers several avenues for improving crops. Though our understanding is not yet complete, synthetic biology has given us opportunities to design, build, and test crop engineering approaches. The ability to produce multi-transgene approaches for engineering whole metabolic pathways can lead to increases in carbon assimilation and nutrient acquisition. I have generated alternative metabolic pathways re-routing photorespiration while simultaneously reducing flux through the native photorespiration pathway using RNA interference. With additional alternative pathway designs and novel technologies such as the CRISPR/ CAS gene editing I am interested in improving gene regulation in synthetic biology and seeking additional strategies to increase plant productivity and nutritional quality.
South PF, Cavanagh, AP, Liu, HW, Ort, DR. (2019) Synthetic glycolate metabolism pathways stimulate crop growth and productivity in the field. Science 2019, v363 (6422).
South PF, Cavanagh AP, Lopez-Calcagno PE, Raines CA, Ort DR. (2018) Optimizing photorespiration for improved crop productivity. Journal of Integrative Plant Biology 2018. Aug.
López-Calcagno PE, Fisk S, Brown KL, Bull SE, South PF, Raines CA. (2018) Overexpressing the H-protein of the glycine cleavage system increases biomass yield in glasshouse and field-grown transgenic tobacco plants. Plant Biotechnology Journal 2018, May pp. 1-11.
South PF, Walker, BJ, Cavanagh, AP, Rolland, V, Badger, M, Ort, DR. (2017) Bile acid sodium symporter BASS6 can transport glycolate and is involved in photorespiratory metabolism in Arabidopsis thaliana. The Plant Cell 2017 Apr; 29 no.4 808-823.
Walker BJ, South PF, Ort DR. (2016) Physiological evidence for plasticity in glycolate/glycerate transport during photorespiration. Photosynthesis Research. 2016 Jul;129(1):93-103.
Patron NJ, Orzaez D, Marillonnet S…South PF, et al…(2015) Standards for Plant Synthetic Biology: A Common Syntax for Exchange of DNA Parts. New Phytologist 2015 Jun; 14
Harmeyer KM, South, PF, Bishop, B, Ogas,J, and Briggs, SD. (2015) Immediate chromatin immunoprecipitation and on-bead quantitative PCR analysis: a versatile and rapid ChIP procedure. Nucleic Acids Research. 2015 Mar 31;43(6): e38.
South PF, Harmeyer KM, Serratore ND, and Briggs SD. (2013) The H3K4 methyltransferase Set1 is involved in maintenance of ergosterol homeostasis and resistance to Brefeldin a. Proceedings of the National Academy of Sciences. 2013 Mar 12;110(11) E1016–E1025.