We use cookies to enhance your experience on our website. By continuing to use our website, you are agreeing to our use of cookies. You can change your cookie settings at any time. Find out more Volume 68 Issue 2 | Journal of Experimental Botany | Oxford Academic Skip to Main Content
Issue Cover
Volume 68, Issue 2
1 January 2017
ISSN 0022-0957
EISSN 1460-2431
Issue navigation

Special Issue: C4 Photosynthesis: 50 Years of Discovery and Innovation


eXtra Botany



A short history of the discovery of the C4 photosynthetic pathway and the subsequent advances made in biochemistry, molecular genetics, physiology, and high-throughput sequence-based approaches are reviewed.

The distribution of C4 photosynthesis in higher plants is summarized by providing a list of C4 evolutionary lineages, their affiliated genera, and species numbers. The most important C4 species are also highlighted.


Analysis of photosynthesis gene expression in multiple C4 lineages indicates that individual genes are regulated at multiple levels and that the mechanisms operate in C3 ancestors.


A rational, model-driven strategy combining genetic and evolutionary engineering is the most promising route to generate a C4 prototype from a C3 plant – and, eventually, C4 rice.


A new genome wide scan method using signals of positive selection identifies C4 candidate genes in the grasses independent of a priori knowledge of C4 biochemistry.

An analysis of exonic and intronic signatures revealed that there was post-transcriptional regulation of cytosolic transcripts during C4 leaf ontogeny.

Systems analysis of freeze-quenched mesophyll and bundle sheath tissues enriched under liquid nitrogen provides a reliable alternative to previously used separation techniques that showed bias in RNA quality.

The genome of Salsola soda allows a transition from C3 to C4 photosynthesis. A developmental transcriptome series revealed novel genes showing expression patterns similar to those encoding C4 proteins.

We identify transcription factors that show conserved patterns of expression in multiple C4 species, both within the Flaveria genus and also in more distantly related C4 plants.

Analysis of the genus Moricandia, which contains C3 and C3–C4 intermediate plants, reveals potential environmental and anatomical constraints to the evolution of C4 photosynthesis.

Evolution of C3–C4 intermediate and C4 lineages are resolved in Salsoleae (Chenopodiaceae), and a model for structural and biochemical changes for the evolution of the Salsoloid form of C4 is considered.

Portulacaceae shows great diversity in C4 photosynthetic phenotypes: all species in clade Cryptopetala are C3-C4 intermediates, while clade Pilosa has a unique anatomical form of Kranz with diversity in C4 biochemistry.

The C3–C4 state moves lineages into C4-like environments, bridging the ecological gap between C3 and C4 species and facilitating C4 evolution.

A spatial separation of 10 µm between primary and secondary carboxylases is sufficient for a single-cell C4 pathway, even in the absence of any intracellular diffusion barriers.

A model based solely on mass-balance constraints refines our understanding of the trade-offs, energy requirements, leaf-level fluxes, and plasticity mechanisms in different biochemical types of assimilation.

Analysis of labeling kinetics, pool sizes, and concentration gradients of metabolites reveals the operation of multiple decarboxylation pathways and rapid movement of carbon between the Calvin–Benson cycle and the CO2-concentrating shuttles in maize.

Carbonic anhydrase and mesophyll conductance are both limiting factors affecting CO2 assimilation rates at low pCO2 as examined in stably transformed lines of the C4 species, Setaria viridis.

Flaveria bidentis carbonic anhydrase 3 catalyses the first step in C4 photosynthesis, with its cognate gene containing an element that shares homology and function with the C4Flaveria MEM1 motif.

Bundle-sheath leakiness of a perennial C4 grass responds dynamically to short-term variation of atmospheric CO2 concentration, and is altered by long-term changes of vapour pressure deficit.

Leaves of two highly productive C4 crops lose photosynthetic efficiency in low light as they become shaded by new leaves forming above, costing the crop up to 10% of potential productivity.

  • Cover Image

    Cover Image

    issue cover
    Cover illustration: (Top) C4 model monocot species Setaria viridis. Photocredit Charles Tambiah. (Middle) The genome of Salsola soda allows a transition from C3 to C4 photosynthesis. Images show transverse sections of cotyledon (top) and a leaf (bottom) of Salsola soda (See Lauterbach et al. pp. 161-176). (Bottom) As leaves of sorghum become shaded in the field they lose photosynthetic efficiency (See Pignon et al. pp. 335-345). Photocredit Kathryn Faith.
  • Front Matter
  • Table of Contents
This Feature Is Available To Subscribers Only

Sign In or Create an Account

This PDF is available to Subscribers Only

View Article Abstract & Purchase Options

For full access to this pdf, sign in to an existing account, or purchase an annual subscription.

Subscribe Now