Combining genetic and evolutionary engineering to establish C4 metabolism in C3 plants

J Exp Bot. 2017 Jan;68(2):117-125. doi: 10.1093/jxb/erw333. Epub 2016 Sep 22.


To feed a world population projected to reach 9 billion people by 2050, the productivity of major crops must be increased by at least 50%. One potential route to boost the productivity of cereals is to equip them genetically with the 'supercharged' C4 type of photosynthesis; however, the necessary genetic modifications are not sufficiently understood for the corresponding genetic engineering programme. In this opinion paper, we discuss a strategy to solve this problem by developing a new paradigm for plant breeding. We propose combining the bioengineering of well-understood traits with subsequent evolutionary engineering, i.e. mutagenesis and artificial selection. An existing mathematical model of C3-C4 evolution is used to choose the most promising path towards this goal. Based on biomathematical simulations, we engineer Arabidopsis thaliana plants that express the central carbon-fixing enzyme Rubisco only in bundle sheath cells (Ru-BSC plants), the localization characteristic for C4 plants. This modification will initially be deleterious, forcing the Ru-BSC plants into a fitness valley from where previously inaccessible adaptive steps towards C4 photosynthesis become accessible through fitness-enhancing mutations. Mutagenized Ru-BSC plants are then screened for improved photosynthesis, and are expected to respond to imposed artificial selection pressures by evolving towards C4 anatomy and biochemistry.

Keywords: Arabidopsis; C4 photosynthesis; artificial selection; biomathematical modelling; evolutionary engineering; genetic engineering; mutagenesis..

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biological Evolution*
  • Genetic Engineering*
  • Photosynthesis / genetics*
  • Plant Breeding / methods*
  • Ribulose-Bisphosphate Carboxylase / genetics
  • Ribulose-Bisphosphate Carboxylase / metabolism


  • Ribulose-Bisphosphate Carboxylase