Walking the C4 pathway

RT Furbank1,2

  1. ARC Centre of Excellence for Translational Photosynthesis, ANU, Canberra ACT 2601, Australia
  2. CSIRO Agriculture and Food, Canberra ACT 2601, Australia

2016 marks 50 years since the publication of the seminal paper from Hatch and Slack describing the biochemical pathway we now know as C4 photosynthesis. In my presentation I will provide insight into the initial discovery of this pathway, the clues which led Hatch and Slack and others to these definitive experiments, some of the intrigue which surrounds the international activities leading up to the discovery and give some personal views on the future of this research field. Although the biochemistry of the basic pathways came quickly, the role of the bundle sheath intermediate CO2 pool took a number of years to be elucidated. C4 photosynthesis functioning as a biochemical CO2 concentrating pump was then linked with the unique Kranz anatomy of C4 plants, already known for many years. Decades of "grind and find" biochemistry accompanied by leaf level physiology defined the regulation of the pathway and the differences in physiological response to the environment between C3 and C4 plants. The more recent advent of plant transformation, high throughput RNA and DNA sequencing and synthetic biology has allowed us carry out biochemical experiments and test hypotheses in planta as well as mine large data sets for bioinformatics driven research. With this knowledge, we now better understand the evolution driven molecular and genetic changes which occurred in the genomes of plants in the transition from C3 to C4. These evolutionary changes are now informing attempts to engineer C4 photosynthesis into rice and improve the C4 engine itself for enhanced food security and to provide novel biofuel feedstocks.