von Caemmerer, SusanneGhannoum, OulaFurbank, Robert2017-12-142017-12-140022-0957http://hdl.handle.net/1885/138112It is now over half a century since the biochemical characterization of the C₄ photosynthetic pathway, and this special issue highlights the sheer breadth of current knowledge. New genomic and transcriptomic information shows that multi-level regulation of gene expression is required for the pathway to function, yet we know it to be one of the most dynamic examples of convergent evolution. Now, a focus on the molecular transition from C₃-C₄ intermediates, together with improved mathematical models, experimental tools and transformation systems, holds great promise for improving C₄ photosynthesis in crops.application/pdf© The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. Box 1. Pioneers of C4 photosynthesis Roger Slack, Hilary Warren and Hal Hatch at the opening of the conference ‘C4 Photosynthesis: past, present and future’ in April 2016. The meeting was held at the ARC Centre of Excellence for Translational Photosynthesis in Canberra, Australia to commemorate the discovery of the C4 pathway and its significance in today’s plant biology and agricultural research (see Hibberd and Furbank, 2016). Hilary Warren (then Johnson) was the first PhD student of Hal Hatch. It is with sadness that we note that Roger Slack passed away on 24 October 2016. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.14c pulse chasec3–c4 intermediate speciesc4 cropsc4 photosynthetic pathwayc4 rice projectco2 fixationhal hatch and roger slackkranz anatomy.convergent evolution2017-0110.1093/jxb/erw491