Research Projects

​​Phosphoenolpyruvate carboxylase (PEPC) is a key enzyme in carbon metabolism, known for its critical role in C4 photosynthesis and stress responses. Emerging evidence suggests its potential involvement in iron (Fe) homeostasis; however, this role remains underexplored, especially across diverse plant species. This project aims to elucidate the regulation and functional role of PEPC under Fe-deficient conditions in both C3 (Arabidopsis and wheat) and C4 (Amaranthus) species. The current proposal will investigate PEPC gene expression and enzyme activity under Fe deficiency in Arabidopsis, wheat, and Amaranthus to identify key PEPC isoforms responsive to Fe stress. Based on these assays, candidate PEPCs will be selected for functional characterization. In Arabidopsis and wheat, reverse genetics approaches including T-DNA insertion lines and TILLING knockouts will be employed to dissect PEPC’s role in Fe acquisition and homeostasis. Phenotypic characterization under Fe-deficient conditions will involve measuring ferric chelate reductase activity, root exudation, photosynthetic efficiency, Fe content (via Perls-DAB and ICP-MS), and chlorophyll levels. Subcellular localization and promoter-reporter assays will further illuminate spatial regulation. In parallel, the functional role of PEPC in carbon allocation and Fe stress responses in Amaranthus will be assessed through generation and characterization of PEPC mutants. Using ¹³C-labeling and metabolic flux analysis, we aim to compare PEPC-mediated carbon partitioning between C3 and C4 systems under Fe-deficiency. Physiological parameters such as photosynthetic efficiency and growth traits will also be compared. Additionally, metabolomic profiling will be integrated to understand the crosstalk between Fe and carbon metabolism. Finally, signaling pathways linked to PEPC function in Fe homeostasis will be explored in Arabidopsis to identify potential regulatory nodes. Together, this work will provide new insights into the convergence of carbon and iron metabolic pathways, enhancing our understanding of nutrient stress responses in crops.