1. SynthSys and School of Biological Sciences, C. H. Waddington Building, University of Edinburgh , King’s Buildings, Edinburgh EH9 3BF , UK
2. Max Planck Institute of Molecular Plant Physiology , Am Muehlenberg 1, 14476 Potsdam-Golm , Germany
3. Department of Metabolic Biology, John Innes Centre , Norwich NR4 7UH , UK
4. Institute of Molecular Plant Biology, ETH , Zurich , Switzerland
5. Department of Botany and Plant Biology, University of Geneva , Geneva , Switzerland
6. SynthSys and EPCC, Bayes Centre, University of Edinburgh , 47 Potterrow, Edinburgh EH8 9BT , UK