Current position
Senior Fellow
Research interests
Plant physiology and molecular biology; Molecular and physiological
analysis of CO2 concentrating mechanisms in cyanobacteria; Construction
and analysis of mutants; CO2 sensing in cyanobacteria; Regulation
of gene expression; Proteomic identification of protein complexes;
Photosynthetic enzymes; Ion transport mechanisms; electron microscopy.
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 long-term 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.
Techniques used:
Analysis of changes in transcript abundance using Real time RT-PCR
Proteome analysis of protein complexes using protein mass spectrometry
Physiological analysis of photosynthetic fluxes using Membrane-inlet
mass spectrometry Structure-function analysis of CO2 transporters
using Site-directed mutagenesis
Construction and Analysis of specific deletion and insertional
mutants.
Selected Publications
Price GD, Sültemeyer D, Klughammer B, Ludwig
M, Badger MR (1998) The functioning of the CO2 concentrating mechanism
in several cyanobacterial strains: a review of general physiological
characteristics, genes, proteins and recent advances (Invited
refereed review with new data). Canadian Journal of Botany
76: 973-1002.
Price GD, von Caemmerer S, Evans JR, Siebke
K, Anderson JM, Badger MR (1998). Photosynthesis is strongly reduced
by antisense suppression of cytochrome bf complex in transgenic
tobacco. Australian Journal of Plant Physiology
25: 445-452.
Klughammer B, Sültemeyer D, Badger MR, Price GD.
(1999) The involvement of NAD(P)H dehydrogenase subunits, NdhD3
and NdhF3, in high affinity CO2 uptake in Synechococcus sp. PCC7002
gives evidence for multiple NDH-1 complexes with specific roles
in cyanobacteria.. Molecular Microbiology 32:
1305-1315.
Omata T, Price GD, Badger MR, Okamura M, Gohta
S, Ogawa T (1999) Identification of an ATP-binding cassette transporter
involved in bicarbonate uptake in the cyanobacterium Synechococcus
sp. Strain PCC7942. Proceedings of the National Academy
of Sciences (U.S.A.) 96: 13571-13576.
Maeda S, Price GD, Badger MR, Enomoto C, Omata
T. (2000) Bicarbonate-binding activity of the CmpA protein of
the cyanobacterium Synechococcus sp. strain PCC 7942 involved
in active transport of bicarbonate. Journal of Biological
Chemistry 275: 20551-55 .
Ludwig M, Sültemeyer D and Price GD. ( 2000) Isolation
of ccmKLMN genes from the marine cyanobacterium, Synechococcus
sp. PCC7002 (Cyanophyceae), and evidence that CcmM is essential
for carboxysome assembly Journal of Phycology 36: 1109-18.
Pike CS, Grieve J, Badger MR and Price GD (2001)
Thermoprotective properties of small heat shock proteins from
rice, tomato, and Synechocystis sp. PCC6803 overexpressed in,
and isolated from, Escherichia coli. Aust. Journal of
Plant Physiology 28: 1219-29.
Maeda S, Badger MR, Price GD (2002) Novel gene
products associated with NdhD3/D4–containing NDH-1 complexes
are involved in photosynthetic CO2 hydration in the cyanobacterium,
Synechococcus sp. PCC7942. Molecular Microbiology
43: 425-436.
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, Maeda S, Omata T and Badger MR (2002)
Modes of active inorganic carbon uptake in the cyanobacterium,
Synechococcus sp. PCC7942. Functional Plant Biology 29:
131-149.
Badger MR and Price GD (2003) CO2 concentrating
mechanisms in cyanobacteria: molecular components, their diversity
and evolution (Review). Journal of Experimental Botany
54: 609-22.
McGinn PJ, Price GD, Maleszka R, Badger MR (2003) Inorganic
carbon limitation and light control the expression of transcripts
related to the CO2-concentrating mechanism in the cyanobacterium
Synechocystis sp. Strain PCC6803. Plant Physiology
132: 218-229.
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