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C4 photosynthesis

IMG_0290The C4 pathway is a fuel injection system for photosynthesis that increases the rate of leaf sugar production in hot climates.  Our research investigates when, how and why C4 photosynthesis evolved.
  1. Which genes are required for C4 photosynthesis and how did they evolve?
  2. What environmental factors drove the evolution of C4 photosynthesis?
  3. How does C4 photosynthesis interact with other physiological processes, and influence the ecology of plants?
  4. To what extent can the ecology of C4 plants be explained by their evolutionary history?
  5. What factors drove the assembly of C4 grassy biomes?

The African grass Alloteropsis semialata is unique among plants in having C3 and C4 variants, and we have recently discovered C3-C4 intermediates in this species. We collaborate with Pascal-Antoine Christin to investigate how photosynthesis evolved in this plant and its implications for the ecology of the species.

We have a long-standing collaboration with Brad Ripley at Rhodes University in this area, carrying out comparative experiments with C4 and C3 grasses in common gardens.

We are collaborating with Lawren Sack at UCLA to look at the interaction of C4 photosynthesis with plant hydraulics.

Selected recent publications in this area

Watcharamongkol, T., Christin, P.-A., Osborne, C.P. (2018) C4 photosynthesis evolved in warm climates but promoted migration to cooler ones. Ecology Letters, doi: 10.1111/ele.12905. link + blog

Atkinson, R.R.L., Mockford, E.J., Bennett, C., Christin, P.-A., Spriggs, E.L., Freckleton, R.P., Thompson, K., Rees, M., Osborne, C.P. (2016) C4 photosynthesis boosts growth through altered physiology, allocation and size. Nature Plants 2, 16038. link

Lundgren, M.R. Besnard, G., Ripley, B.S., Chatelet, D., Namaganda, M., Vorontsova, M.S., Hall, R.C., Lehmann, C.E.R., Elia, J., Osborne, C.P., Christin, P.-A. (2015) C4 photosynthesis broadens the niche within a species complex. Ecology Letters, 18, 1021-1029. link

Lundgren, M.R., Christin, P.-A., Ripley, B.S., Besnard, G., Long, C., Hattersley, P.W., Ellis, R.P., Osborne, C.P. (2016) Evolutionary implications of C3-C4 intermediates in the grass Alloteropsis semialata. Plant, Cell and Environment, 9, 1874-1885. link

Simpson, K.J., Ripley, B.S., Christin, P.-A., Belcher, C.M., Lehmann, C.E., Thomas, G.H., Osborne, C.P. (2016) Determinants of flammability in savanna grass species. Journal of Ecology, 104, 138-148. link

Osborne, C.P., Charles-Dominique, T., Stevens, N., Bond, W.J., Midgley, G., Lehmann, C.E.R. (2018) Human impacts in African savannas are mediated by plant functional traits. New Phytologist, 220, 10-24. link

Fox, D.L., Pau, S., Taylor, L., Strömberg, C.A.E., Osborne, C.P., Bradshaw., C., Conn, S., Beerling, D.J., Still, C.J. (2018) Climatic controls on Cgrassland distributions during the Neogene: a model-data comparison. Frontiers in Ecology and Evolution, 6, 147. link

Dunning, L.T., Lundgren, M.R., Moreno-Villena, J.J., Namaganda, M., Edwards, E.J., Nosil, P., Osborne, C.P., Christin, P.-A. (2017) Introgression and repeated co-option facilitated the recurrent emergence of C4 photosynthesis among close relatives. Evolution, 71, 1541-1555. link

Bianconi, M.E., Dunning, L.T., Moreno-Villena, J.J., Osborne, C.P., Christin, P.-A. (2018). Gene duplication and dosage effects during the early emergence of Cphotosynthesis. Journal of Experimental Botany, 69, 1967-1980. link

Moreno-Villena, J.J., Dunning, L.T., Osborne, C.P., Christin, P.-A. (2018) Highly expressed genes are preferentially co-opted for novel metabolism. Molecular Biology and Evolution, 35, 94–106. link

Olofsson J.K., Bianconi, M., Bernard, G., Dunning, L.T., Lundgren, M.R., Holota, H., Vorontsova, M.S., Teerawata, A., Muasya, M., Nosil, P., Osborne, C.P., Christin, P.-A. (2016) Genome biogeography reveals the intraspecific spread of adaptive mutations for a complex trait. Molecular Ecology, 25, 6107-6123. link