BMB and CDIB Divisions
My research is centered on how plants and algae acquire the CO2 they need for photosynthesis. Phytoplankton and algae in aquatic environments account for almost 50% of the carbon dioxide (CO2) fixed by photosynthesis on the Earth. Because the diffusion of CO2 is almost 10,000 times slower in water than in air, almost all of these organisms have a mechanism that concentrates CO2 from the environment for photosynthesis. This CO2 concentrating mechanism (CCM) is essential for photosynthesis at atmospheric levels of CO2 and for the survival of algae. In photosynthetic cyanobacteria, the CCM includes membrane proteins that transport bicarbonate (HCO3-) from the medium into the cell and a carbonic anhydrase. The carbonic anhydrase is needed to convert the accumulated HCO3- to CO2 for Rubisco, the enzyme that fixes CO2. The CCM in eukaryotic algae is less well understood but is known to involve transport proteins and multiple carbonic anhydrases. The goal of my laboratory is to characterize the CCM in the eukaryotic green alga Chlamydomonas reinhardtii.
We use the model unicellular organism, C. reinhardtii, for our studies because the genome is sequenced, it has a robust CO2 concentrating mechanism and mutant strains that have defects in the CO2 concentrating mechanism have been identified. These are important tools that we use to determine how the CCM functions. This work will help us understand how the CO2 concentrating mechanism contributes to the global carbon cycle and will help us predict how algae will respond to rising atmospheric CO2 levels.
Previous work from my laboratory has established that C. reinhardtii has at least nine genes encoding carbonic anhydrases. We are presently working to characterize these proteins, as well as determine their intracellular locations and their physiological roles. We use a combination of genetic, molecular and physiological techniques in these studies. Another aim of my laboratory is to identify and characterize transport proteins that carry HCO3-. Since inorganic carbon must cross both the plasma membrane and two chloroplast envelopes to get to Rubisco, we expect that there will be multiple proteins transporting HCO3- in the CCM of C. reinhardtii. We have identified a number of candidate genes that might encode important transport proteins. If you want to know more about my research program and the people in my research group please go to the Moroney lab page.
Ma, Y., Pollock, S.V., Xiao, Y., Cunnusamy, K., Moroney J.V. 2011. Identification of a novel gene required for normal pyrenoid formation in Chlamydomonas reinhardtii. Plant Physiol. 156: 884-896
Moroney J.V., Ma Y., Frey W.D., Fusilier K., Pham T.T., Simms T.A.., DiMario, R.J., Yang, J. and Mukherjee B., 2011. The carbonic anhydrase isoforms of Chlamydomonas reinhardtii: expression, intracellular location and physiological roles. Photosyn. Res. 109:133-149 DOI: 10.1007/s11120-011-9635-3
Mukherjee B, Moroney JV (2011) Algal Carbon Dioxide Concentrating Mechanisms. In: eLS 2011, John Wiley & Sons, Ltd: Chichester http://www.els.net/ [DOI: 10.1002/9780470015902.a0000314.pub3]
Ohnishi, N., Mukherjee, B., Tsujikawa, T., Yanase, M., Nakano, H., Moroney, J.V., Fukuzawa, H. 2010. Expression of LCI1, a low-CO2-inducible protein, enhances the inorganic carbon uptake in a green alga Chlamydomonas reinhardtii. Plant Cell 22: 3105-3117
Brumfield KM, Moroney JV, Moore TS, Simms TA, Donze D (2010) Identification of ERG3, a gene involve in the biosynthesis of ergosterol in Chlamydomonas reinhardtii. PLOS ONE,5: e8659
Moroney JV, Ynalvez R A (2009) Algal Photosynthesis. In: ENCYCLOPEDIA OF LIFE SCIENCES. John Wiley & Sons, Ltd: Chichester http://www.els.net/[Doi:10.1002/9780470015902.a0000322.pub2]
Zhang S, Spann KW, Frankel LK, Moroney JV Bricker TM (2008) Identification of two novel genes, sll0804 and slr1306, associated with the CO2-concentrating mechanism in the cyanobacterium Synechocystis sp. PCC 6803. J. Bact. 190: 8234-8237
Chauvin LS, Tural B Moroney JV (2008) Chlamydomonas reinhardtii has genes for both glycolate oxidase and glycolate dehydrogenase. In Photosynthesis: Energy from the sun. Proceedings of the 14th International Congress on Photosynthesis. Ed. By J. Allen, B. Osmond, J.K. Golbeck and E. Gantt, Springer, pp 823-827
Ynalvez RA, Xiao Y, Ward AS, Cunnusamy K and Moroney JV (2008) Isolation and characterization of two closely related beta-carbonic anhydrases from Chlamydomonas reinhardtii. Physiol. Plant. 133: 15-26
Ynalvez RA and Moroney JV (2008) Isolation and Characterization of the Novel Gene CIA7 from the BleR Insertional Mutant of Chlamydomonas reinhardtii. Funct. Plant Biol. 35: 373-381
Moroney JV and Ynalvez RA (2007) A proposed carbon dioxide concentration mechanism in Chlamydomonas reinhardtii. Eukaryotic Cell 6: 1251-1259
Merchant SS et al. (2007) The Chlamydomonas genome reveals the evolution of key animal and plant functions. Science 318: 245-250
Bartlett SG, Mitra M, Moroney JV (2006) CO2 concentrating mechanisms. In Advances in Photosynthesis vol. 23, The Structure and Function of Plastids. Ed. by R.R. Wise and J. K. Hoober, Springer, Dordrecht, pp. 253-271.
Mason CB, Bricker TM, Moroney JV (2006) A rapid method for chloroplast isolation from the green alga Chlamydomonas reinhardtii - Nature-Protocols 1:2227 – 2230 (also featured on the cover)