Dr. Lianhong Gu is a Distinguished Scientist and Task Leader in the Environmental Sciences Division, Oak Ridge National Laboratory, USA. Dr. Gu has a B.S. in Physics from Jiangsu Normal University (formerly Xuzhou Normal University), M.S. in Ecology from Chinese Academy of Sciences, and PhD in Environmental Science from University of Virginia. Dr. Gu is an expert in eddy covariance, sun-induced chlorophyll fluorescence, and photosynthesis.
Optimizing the electron transport chain to sustainably improve photosynthesis
L. GU
Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
Genetically improving photosynthesis is a key strategy to boosting crop production to meet the rising demand for food and fuel by a rapidly growing global population in a warming climate. Many components of the photosynthetic apparatus have been targeted for genetic modification for improving photosynthesis. Successful translation of these modifications into increased plant productivity in fluctuating environments will depend on whether the electron transport chain (ETC) can support the increased electron transport rate without risking overreduction and photodamage. At the present atmospheric conditions, ETC appears suboptimal and will likely have to be modified to support proposed photosynthetic improvements, and to maintain energy balance. Here we derive photochemical equations to quantify the transport capacity and corresponding reduction level based on the kinetics of redox reaction along the ETC. Using these theoretical equations and measurements from diverse C 3 /C 4 species across environments, we identify several strategies that can simultaneously increase the transport capacity and decrease the reduction level of ETC. These include increasing the abundances of reaction centers, cytochrome b 6 f complex, and mobile electron carriers, improving their redox kinetics, and decreasing the fraction of secondary quinone-nonreducing photosystem II reaction centers. Our findings facilitate the development of sustainable photosynthetic systems for greater crop yields.