Professor Emeritus, School of Biological Sciences. Ph.D. 1969, University of California, Riverside.
For more than 30 years, I have worked in photosynthesis, including the effects of environmental stress and potential global climate change with studies ranging from the cellular to the whole plant level. Research on the mechanism and evolution of carbon assimilation includes studies on C3, C4 and Crassulacean acid metabolism species. Research on C4 photosynthesis has been focused on diversity in structure, function and evolution. One project involves studies in the family Chenopodiaceae that includes collections of species from Central Asian Deserts adapted to high temperature, drought, and salinity with the goal to characterize the structural, functional, and evolutionary relationships among species and their adaptation to different environments.
Recently, studies on chenopods shows that C4 photosynthesis can occur in a single photosynthetic cell (i.e., without the Kranz anatomy that was previously thought to be required). Another project, with Dr. Okita, involves studies on source-sink relationships in carbon partitioning using Arabidopsis as a model system, and rice as an important crop.
The ultimate goal of this research, besides basic knowledge about photosynthesis, is directed toward enhancing productivity of crops. For example, the discovery of single cell C4 photosynthesis breaks the paradigm that it would be essential to engineer Kranz anatomy into C3 crop plants in order for them to perform more efficiently under stressful conditions.
Furbank RT, S von Caemmerer, J Sheehy, G Edwards. 2009. C4 rice: A challenge for plant phenomics. Functional Plant Biology 36: 845-856.
Park, J-H, M. Knoblauch, TW Okita and GE Edwards. 2009. Structural changes in the vacuole and cytoskeleton are key to development of the two cytoplasmic domains supporting single-cell C4 photosynthesis in Bienertia sinuspersici . Planta. 229:369-382.
Park, J-H, TW Okita and GE Edwards. 2009. Salt tolerant mechanisms in single-cell C4 species Bienertia sinuspersici and Suaeda aralocaspica (Chenopodiaceae). Plant Science 176: 616-626.
Nagai, Y, C Sakulsingharoj, GE Edwards, T Greene, H Sato, B Blakeslee, T Okita. 2009. Control of starch synthesis in cereals: metabolite anlysis of transgenic rice expressing upregulated cytoplasmic ADP-glucose pyrophosphorylase in developing seeds. Plant Cell Physiology. 50: 635-643.
Maricle, BR, NK Koteyeva, EV Voznesenskaya, JR Thomasson, GE Edwards. 2009. Diversity in leaf anatomy, and stomatal distribution and conductance among ecotypes in the C4 genus Spartina (Poaceae).New Phytologist. 184: 216-233.
Smith, ME, NK Koteyeva, EV Voznesenskaya, TW Okita, GE Edwards. 2009. Photosynthetic features of non-Kranz type versus Kranz type C4 and C3 species species in subfamily Suaedoideae (Chenopodiaceae). Functional Plant Biology. 36: 770-782.
Kiirats, O, JA Cruz, GE Edwards and DM Kramer. 2009. Feedback limitation of photosynthesis at high CO2 acts by modulating the activity of the chloroplast ATP synthase. Functional Plant Biology 36:893-901.
Akhani, H, MV Lara, M Ghasemkhani, H Ziegler and GE Edwards. 2009. Does Bienertia cycloptera with the single-cell system of C4 photosynthesis exhibit a seasonal pattern of d13C values in nature similar to co-existing C4 Chenopodiaceae having the dual-cell (Kranz) system? Photosynthesis Research. 99:23-36.
Edwards, GE and EV Voznesenskaya. C4 photosynthesis: Kranz Forms and Single-Cell C4 in Terrestrial Plants. Chapter in Advances in Photosynthesis Research, Photosynthesis and Related CO2 Concentrating Mechanisms. A. Raghavendra and R. Sage, eds. Kluwer, The Netherlands. In Press.
Voznesenskaya, EV, H Akhani, NK Koteyeva, SDX Chuong, EH Roalson, O Kiirats, VR Franceschi and GE Edwards. 2008. Structural, biochemical and physiological characterization of photosynthesis in C3 and C4 species of the genus Tecticornia (family Chenopodiaceae) and a phylogenetic placement of the photosynthetic types. Journal of Experimental Botany Special Issue on CAM and C4 photosynthesis 59: 1715-1734.
Maricle, B.R., R.W. Lee, C.E. Hellquist, O. Kiirats, G.E. Edwards. Effects of salinity on chlorophyll fluorescence and CO2 fixation in C4 estuarine grasses. Photosynthetica (in press).
Akhani H., G.E .Edwards, E. Roalson. Diversification of the Old World Salsoleae s.l. (Chenopodiaceae): Molecular phylogenetic analysis of nuclear and chloroplast datasets and a revised classification. International Journal of Plant Sciences (in press).
Ivanov, B., K. Asada, G.E. Edwards. Analysis of donors of electrons to photosystem I and cyclic electron flow by redox kinetics of P700 in chloroplasts of isolated bundle sheath strands of maize. Photosynthesis Research (in press).
Murphy, L.R., J. Barroca, V.R. Franceschi, R. Lee, E.H. Roalson, G.E. Edwards and M.S.B. Ku. Diversity and plasticity of C4 photosynthesis in Eleocharis (Cyperaceae). Functional Plant Biol (in press).
Sickler, C.M., G.E. Edwards, O. Kiirats, Z. Gao and W. Loescher. 2007. Response of mannitol-producing Arabidopsis thaliana to abiotic stress. Special Issue in Memory of Vincent R. Franceschi. Functional Plant Biol. 34:382-391.
Boyd, C.N., V.R. Franceschi, S.D.X. Chuong, H. Akhani, O. Kiirats, M. Smith and G.E. Edwards. 2007. Flowers of Bienertia cycloptera and Suaeda aralocaspica (Chenopodiaceae) complete the life cycle performing single-cell C4 photosynthesis. Special Issue in Memory of Vincent R. Franceschi. Functional Plant Biology 34:268-281.
Voznesenskaya E.V., N. Koteyeva, S.D.X. Chuong, A. Ivanova, J. Barroca and G.E. Edwards. 2007. Physiological, anatomical and biochemical characterization of photosynthetic types in genus Cleome (Cleomaceae). Special Issue in Memory of Vincent R. Franceschi. Functional Plant Biol. 34:247-267.
Lara, M.V., S.D.X. Chuong, H. Akhani, C.S. Andreo and G.E. Edwards. 2006. Species having C4 single cell type photosynthesis in family Chenopodiaceae evolved a photosynthetic phosphoenolpyruvate carboxylase like that of C4 Kranz type species. Plant Physiology 142:673-684.
Edwards, G.E., E. Voznesenskaya, M. Smith, N. Koteyeva, Y. Park, J.-H. Park, O. Kiirats, T.W. Okita and S.D.X. Chuong. Breaking the Kranz paradigm in terrestrial C4 plants: Does it hold promise for C4 rice? In: Proceedings of the 2006 meeting of the C4 Rice Consortium (Sheehy J.E., Mitchell P.L. and Hardy B., editors). International Rice Research Institute, Makati City, Philippines.
Chuong, S.D.X., V.R. Franceschi and G.E. Edwards. 2006. Two unique patterns of organelle partitioning required for C4 photosynthesis in a single cell are maintained by the cytoskeleton in family Chenopodiaceae. The Plant Cell 18:2207-2223.
Barkan, L., M.A. Evans and G.E. Edwards. 2006. Increasing UV-B induces biphasic leaf cell expansion in Phaseolus vulgaris, suggesting multiple mechanisms for controlling plant growth. Photochemistry and Photobiology 82:1612-1620.
Kapralov M.V., H. Akhani, E.V. Voznesenskaya, G. Edwards, V. Franceschi, E. Roalson. 2006. Phylogenetic relationships in the Salicornioideae/Suaedoideae/Salsoloideae s.l. (Chenopodiaceae) clade and a clarification of the phylogenetic position of Bienertia and Alexandra using multiple DNA sequence datasets. Systematic Botany 31:571-585
Voznesenskaya, E.V., V.R. Franceschi, S.D.X. Chuong and G.E. Edwards. 2006. Functional characterization of phosphoenolpyruvate carboxykinase type C4 leaf anatomy: Immuno, cytochemical and ultrastructural analyses. Annals of Botany 98:77-91.
Obana, Y., D. Omoto, C. Kato, K. Matsumoto, Y. Nagai, I.H. Kavakli, S. Hamada, G.E. Edwards, T.W. Okita, H. Matsui and H. Ito. 2006. Enhanced turnover of transitory starch by expression of up-regulated ADP-glucose pyrophosphorylases in Arabidopsis thaliana. Plant Science 170:1-11.
Voznesenskaya E.V., N.K. Koteyeva, S.D.X. Chuong, G.E. Edwards, H. Akhani and V.R. Franceschi. 2005. Differentiation of cellular and biochemical features of the single cell C4 syndrome during leaf development in Bienertia cycloptera (Chenopodiaceae). (article highlighted on cover page of issue) Am. J. Bot. 92:1784-1795.
Barroca J., L.R. Murphy, V.R. Franceschi, R. Lee, E. Roalson, G.E. Edwards, M.S. Ku. 2005. Diversification and plasticity of C4 photosynthetic pathway in Eleocharis (Cyperaceae). In: Photosynthesis: Fundamental Aspects to Global Perspectives. Eds. A. van der Est and D. Bruce. Springer. pp. 646-648.
Akhani H., J. Barroca, N. Koteyeva, E. Voznesenskaya, V. Franceschi, G. Edwards, S.M. Ghaffari, W. Stichler and H. Ziegler. 2005. Bienertia sinuspersici (Chenopodiaceae): A new species from SW Asia and discovery of a third terrestrial C4 plant without Kranz anatomy. Systematic Botany 30:290-301.
Kramer D.M., A. Kanazawa, J.A. Cruz, B. Ivanov, and G.E. Edwards. 2005. The relationship between photosynthetic electron transfer and its regulation. In: G.C. Papageorgiou, Govindjee, eds, Chlorophyll a Fluorescence: A Signature of Photosynthesis. Springer, New York, NY. pp. 251-278.
Cruz J.A., T.J. Avenson, A. Kanazawa, K. Takizawa, G.E. Edwards, D.M. Kramer. 2005. Plasticity in light reactions of photosynthesis for energy production and photoprotection. J Exp Bot. 56:395-406.
Ivanov B., K. Asada, D. Kramer and G.E. Edwards. 2005. Characterization of photosynthetic electron transport in bundle sheath cells of maize. Ascorbate can effectively charge cyclic electron flow. Planta 220:572-581.
Voznesenskaya E.V., S.D.X. Chuong, O. Kiirats, V.R. Franceschi, G.E. Edwards. 2005. Evidence that C4 species in genus Stipagrostis, family Poaceae, is NADP-malic enzyme subtype with nonclassical type of Kranz anatomy (Stipagrostoid). Plant Science 168:731-739. Voznesenskaya E.V., S.D.X. Choung, N.K. Koteyeva, G.E. Edwards, V.R. Franceschi. 2005. Functional compartmentation of C4 photosynthesis in the triple-layered chlorenchyma of Aristida (Poaceae). Functional Plant Biology 32:67-77