Chloroplasts are the site of photosynthesis and the defining organelle of green plants. They have the essential role of reducing atmospheric carbon dioxide, which is ultimately the source of food and feed stocks. They are also involved in the synthesis of many nutrients and specialized chemicals useful to humans, as well as playing a role in sensing changes in the environment. Most of the functions of chloroplasts (and other plastids) are carried out by proteins encoded in the nucleus, the products of the Plastid-targeted Nuclear Genes (PNGs). This project, through an integration of computational and experimental approaches, will provide a mechanistic understanding of how PNGs are regulated transcriptionally in the model plant Arabidopsis, identify what the putative roles of the PNGs are, and define how various chloroplast functions are connected. Functions of PNGs implicated in amino acid metabolic networks will be experimentally verified. These studies will lead to a better understanding of plastid biology and will also broadly inform systems approaches to biology.
Broader Impacts: In addition to enhancing our understanding of regulatory and metabolic networks in plastid function, this project will continue to make use of and disseminate the findings through a publicly available phenotype database (www.plastid.msu.edu ) that is of value to the scientific community in many contexts, including research and development for genetically-engineered crop plants. In addition to providing interdisciplinary training to postdoctoral fellows and graduate students, the project will integrate research and education as part of a successful summer internship program (www.plantgenomics.msu.edu). Junior and senior undergraduate students will work in participating laboratories each summer performing research related to the project. This program will have a strong emphasis on the recruitment and training of underrepresented minorities and women.