Photosynthetic Energy Capture, Conversion and Storage: From Fundamental Mechanisms to Modular Engineering
PI: Christoph Benning. Co-Investigators: Federica Brandizzi, Danny D. Ducat, Gregg A. Howe, Jianping Hu, Cheryl A. Kerfeld, David M. Kramer, Thomas D. Sharkey, Daniela Strenkert, Josh Vermaas, Berkley Walker
Michigan State University-DOE Plant Research Laboratory, East Lansing, Michigan 48824
The conversion of sunlight into chemical energy by photosynthesis is the basic biological process driving life on Earth. Photosynthesis sustainably generates food, feed, energy-rich biomolecules, soil organic carbon, and fossil fuels over geological time, while sequestering atmospheric CO2. An interdisciplinary team of 11 investigators and talented scientists with complementary expertise has come together in the Plant Research Laboratory with the long-term goal of exploring basic processes of light capture and conversion into products sustaining the growth of cyanobacteria, algae, and plants. Collectively, we strive to gain an understanding of the natural dynamic aspects of photosynthesis that ensure the robustness of photosynthetic processes in nature under environmental conditions ranging from extreme temperatures to biotic insults. Furthermore, the need of photosynthetic organisms to cope with varying conditions may limit their productivity in agricultural settings. We are developing strategies to overcome these limitations through the engineering or recombination of photosynthetic modules to meet current and future challenges. We expect that gaining a multiscale mechanistic photosynthetic knowledge will allow us to improve photosynthetic efficiency, and thereby plant productivity, expanding the production of photosynthesis-based bioproducts.
The project spans different scales of time and space and is organized accordingly into three Subprojects ranging from photon and electron behavior to the molecular, cellular, and organismal scales. Processes covered include the interaction of photons with pigment protein complexes, biochemical energy conversions carried out by protein and membrane structures, and ultimately photosynthesis in the contexts of cells and organisms, leading to a comprehensive, multiscale understanding of photosynthetic processes. Photosynthetic organisms are faced with a dynamic environment that requires tradeoffs to compensate for potentially toxic or unproductive side reactions of light capture and conversion such as the formation of reactive oxygen species or compensation for the oxygenase activity of the carbon fixing enzyme, rubisco. Hence in Subproject A, we address specific mechanistic questions about the regulation of initial energy storing reactions and how energy is targeted to the correct reactions while avoiding the generation of deleterious reactive oxygen. In Subproject B, we apply the engineering concept of modularity to photosynthesis, starting with the carboxysome and phycobilisome modules of cyanobacteria. These function in the mesoscale of biological organization and are ideally suited for transplantation into new contexts, for example by engineering and introducing bacterial microcompartments into chloroplasts. In Subproject C we study balancing activities across multiple sub-processes throughout the cell to achieve high photosynthetic flux and efficiency. Emphasis is placed on the integration of primary photosynthesis with processes that are essential to photosynthetic performance, but which occur within the larger context of the cell or organism. Examples include photorespiration with the transport of metabolites between organelles requiring the formation of contact sites, as well as mechanisms of carbon partitioning occurring naturally such as balancing of growth versus defense or engineered towards novel products.
Many Plant Research Laboratory groups with their specific expertise are participating in more than one Subproject, and many research themes transcend more than one Subproject, reflecting the collaborative nature of the Plant Research Laboratory: A core value that enables synergistic and interdisciplinary research and leads to unique discoveries. Synergy will also derive from the exchange of ideas among participants of diverse backgrounds, a concept that is embraced and fostered by the Plant Research Laboratory through open monthly Subproject meetings, weekly student and postdoc presentations in the Tuesday Noon Seminar Series, annual retreats, and the activities of the recently formed Plant Research Laboratory Community Building and Outreach Committee.
