Price Lab - The cyanobacterial CO2 Concentrating Mechanism and the use of Synthetic Biology to transfer it to C3 crop plants

Transfer of cyanobacterial CCM genes in plant chloroplasts

The Price lab is presently focusing on the molecular biology and physiology of photosynthesis in cyanobacteria (blue-green photosynthetic bacteria) with emphasis on gaining a full understanding of the adaptive mechanism known as a the 'CO2 concentrating mechanism' in these organisms. The CCM operates to elevate the CO2 concentration around the otherwise substrate-limited primary carboxylase, Rubisco, thus improving the efficiency of photosynthetic CO2 fixation. The system features inducible and constitutive transporters for CO2 and HCO3- that actively accumulate HCO3- within the cell through a light-dependent process. Accumulated HCO3- then enters a unique polyhedral Rubisco-containing organelle known as a carboxysome. Here CO2 is generated and maintained at a high steady state concentration with the aid of a carbonic anhydrase enzyme that is specifically located in the carboxysome. In addition, a special property of the carboxysome retards CO2 leakage leading to efficient CO2 fixation. We have produced a suite of defined CCM mutants for intensive analysis. Combined with the existence of several complete genome sequence databases for cyanobacteria, plus some modern molecular techniques, we have some powerful resources available for the molecular elucidation of the CCM. A present goal of this work is to allow the engineering of some useful CCM components into higher plants so that water and nitrogen-use efficiency can be improved.

  • Synthetic biology approaches to understanding mechanisms of inorganic carbon uptake.
  • Transfer of CCM genes to plant chloroplasts (RIPE project) to improve photosynthetic CO2 fixation efficiency.
  • Synthetic biology approaches to building carboxysomes in foreign hosts.
  • Proteomic analysis of protein complexes using protein mass spectrometry.
  • Physiological analysis of photosynthetic fluxes using Membrane-inlet mass spectrometry (MIMS).
  • Structure-function analysis of bicarbonate transporters.
  • Construction and Analysis of specific deletion and insertional mutants; bioinformatics and phylogenetics.
  • Engineering of plants with altered gene expressions used for testing for bottlenecks in photosynthesis.



Graeme Price

Graeme Price
Professor Dean Price is a previous recipient of an ARC National Research Fellowship and a Queen Elizabeth II Research...

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Selected publications

  • Badger MR, Hanson D and Price GD (2002) Evolution and diversity of CO2 concentrating mechanisms in cyanobacteria. Functional Plant Biology 29: 161-173.
  • Price GD, Woodger FJ, Badger MR, Howitt SM, Tucker L (2004) Identification of a SulP-type bicarbonate transporter in marine cyanobacteria. Proceedings of the National Academy of Science (USA). 101 (52): 18228-18233.
  • Woodger FJ, Badger MR, and Price GD (2005) Sensing of inorganic carbon limitation in Synechococcus PCC7942 Is Correlated with the Size of the internal inorganic carbon pool and involves oxygen. Plant Physiology. 39: 1959-1969.
  • Woodger FJ, Bryant DA, and Price GD (2007) Transcriptional regulation of the CO2-concentrating mechanism in a euryhaline, coastal marine cyanobacterium, Synechococcus sp. PCC7002: role of NdhR/CcmR. Journal of Bacteriology. 189: 3335-3347.
  • Long BM, Badger MR, Whitney SM and Price GD (2007) Analysis of Carboxysomes from Synechococcus PCC7942 Reveals Multiple Rubisco Complexes with Carboxysomal Proteins CcmM and CcaA. Journal of Biological Chemistry. 282 : 29323-35.
  • Price GD, Badger MR, Woodger FJ, Long BM (2008) Advances in understanding the cyanobacterial CO2 concentrating mechanism (CCM): functional components, Ci transporters, diversity, genetic regulation and prospects for engineering into plants. Journal of Experimental Botany. 69: 1441-1461.
  • Shelden MC, Howitt SM, Price GD (2010) Membrane topology of the cyanobacterial bicarbonate transporter, BicA, a member of the SulP (SLC26A) family. Molecular Membrane Biology. 27: 12-23. (Figure 2 selected for the cover page of issue 27-1).
  • Long BM, Tucker L, Badger MR and Price GD (2010) Functional Cyanobacterial -Carboxysomes Have an Absolute Requirement for Both Long and Short Forms of the CcmM Protein1. Plant Physiology. 153: 285–293.
  • Price GD, Badger MR, von Caemmerer S (2011) The prospect of using cyanobacterial bicarbonate transporters to improve leaf photosynthesis in C3 crop plants (Invited Focus Issue). Plant Physiology.
  • Price GD, Howitt SM (2011) The cyanobacterial bicarbonate transporter, BicA: its physiological role and the implications of structural similarities with human SLC26 transporters (Invited review). Biochemistry and Cell Biology  89: 178-188.
  • Price GD (2011) Inorganic carbon transporters of the cyanobacterial CO2 concentrating mechanism (Invited Review). Photosynthesis Research 109: 47-57.  
  • Rae BD, Förster B, Badger MR and  Price GD (2011) The CO2-concentrating mechanism of Synechococcus WH5701 is composed of native and horizontally-acquired components. Photosynthesis Research 109: 59-72.
  •  Long BM, Rae BD, Badger MR and  Price GD (2011) Over-expression of the β-carboxysomal CcmM protein in Synechococcus PCC7942 reveals a tight co-regulation of carboxysomal carbonic anhydrase (CcaA) and M58 content. Photosynthesis Research 109: 33-45.
  •  Price GD, Shelden MC, Howitt SM (2011) Membrane topology of the cyanobacterial bicarbonate transporter, SbtA, and identification of potential regulatory loops. Molecular Membrane Biology.  28: 265-275.
  •  Rae BD, Long BM, Badger MR and  Price GD (2012) Structural determinants of the outer shell of b-carboxysomes in Synechococcus elongatus PCC 7942: Roles for CcmK2, K3-K4, CcmO, and CcmL. PlosOne  7: e43871.
  • Price GD, Pengelly JJL, Forster B, Du J, Whitney SM, von Caemmerer S, Badger MR, Howitt SM, Evans JR. (2013) The cyanobacterial CCM as a source of genes for improving photosynthetic CO2 fixation in crop species (Invited Review). Journal of Experimental Botany 64: 753-68.
  • Rae BD, Long BM, Badger MR and Price GD (2013) The function, composition and evolution of the two types of carboxysomes: polyhedral micro-compartments that facilitate CO2 fixation in cyanobacteria and some proteobacteria. (Invited Review). Microbiology and Molecular Biology Reviews  77: 357-359
  • Rae BD, Long BM, Whitehead LF, Forster B, Badger MR and  Price GD (2013) Cyanobacterial carboxysomes: micro-compartments that facilitate CO2 fixation (Invited review). Journal of Molecular Microbiology and Biotechnology  23(4-5): 300-307
  • Pengelly JJL, Forster B, , von Caemmerer S, Badger MR, Price GD, Whitney SM (2014) Transplastomic integration of a cyanobacterial bicarbonate transporter into tobacco chloroplasts. Journal of Experimental Botany 65:3071-80
  • Whitehead L, Long BM, Price GD and Badger MR (2014) Comparing the in vivo function of α- and β-carboxysomes in two model cyanobacteria. Plant Physiology 165: 398-411.
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News & events


July saw the 2016 Stable Isotopes in Biosphere Systems (SIBS) workshop held at James Cook University in Sunny QLD. A contingent of about 25 students from across Australia, China and the UK came tog
Rob Sharwood
RSB Plant Scientist Rob Sharwood has been awarded a T
Gender balance in science has been a widely-discussed topic this National Science Week.
Congratulations to the six RSB members who have been promoted to Level E Professor as of 1 January 2015.



Laura Wey

A university degree that helps put food on the table

Laura Wey has used her undergraduate research experience at ANU to help grow a better future for us all.


Photosynthesis is an essential process that involves using sunlight to convert carbon dioxide and water into sugar molecules and oxygen.

Updated:  25 June 2017/Responsible Officer:  Director RSB/Page Contact:  Webmaster RSB