Nitrogen is an essential macronutrient for plant growth. While a few plants acquire fixed nitrogen via symbioses with microorganisms, most plants obtain nitrogen through uptake from the soil. The application of nitrogen-containing fertilizers is widely used to enhance plant growth. However, artificial fertilizers are expensive and have serious negative environmental effects, including degradation of soil quality and runoff contaminating of water sources. Engineering crop plants to fix nitrogen would cut down the cost for nitrogen in fertilizers and largely improve the efficiency of nitrogen utilization by plants. However, the detailed mechanism that allows oxygenic photosynthetic cells to conduct N2 fixation is not clear. The objective of this project is to develop and apply advanced synthetic biology tools to determine the minimal unites that are required to convert Synechocystis 6803, a non-diazotrophic cyanobacterium, into a nitrogen-fixing organism. By achieving this goal, the mechanisms that allow oxygen-evolving cells to fix nitrogen will also be better understood. This knowledge would make significant contributions to the efforts of increasing nitrogen availability to crop plants.
Selected Project Publications
Liu, Deng, et al. “Engineering Nitrogen Fixation Activity in an Oxygenic Phototroph.” mBio (2018).
Liu, D., and Pakrasi, H.B. “Exploring native genetic elements as plug-in tools for synthetic biology in the cyanobacterium Synechocystis sp. PCC 6803.” Microbial Cell Factories (2018).
Mueller, T.J., Welsh, E.A., Pakrasi, H.B., and Maranas, C.D. 2015 “Identifying Regulatory Changes to Facilitate Nitrogen Fixation in the Nondiazotroph Synechocystis sp. PCC 6803” ACS Synth. Biol. | DOI: 10.1021/acssynbio.5b00202
Aryal, U. K., Callister, S. J., McMahon, B., McCue, L. A., Brown, J., Stöckel, J., Liberton, M., Mishra, S., Zhang, X., Nicora, C. D., Angel, T., Koppenaal, D. W., Smith, R. D., Pakrasi, H. B. and Sherman, L. A. 2014 ″Proteomic profiles of five strains of oxygenic photosynthetic cyanobacteria of the genus Cyanothece.” J. Proteome Res. , 13: 3262-3276 .
Krishnakumar S, Gaudana SB, Viswanathan GA, Pakrasi HB and Wangikar PP (2013) Rhythm of carbon and nitrogen fixation in unicellular cyanobacteria under turbulent and highly aerobic conditions.Biotechnology and Bioengineering , 110: 2371-2379.
Stockel J, Elvitigala T, Liberton M, Pakrasi HB (2013) “Carbon availability affects diurnally controlled processes and cell morphology of Cyanothece 51142″ PLoS ONE ; 8 (2):e56887.
Bandyopadhyay A, Elvitigala T, Liberton M, Pakrasi HB (2013) “Variations in the Rhythms of Respiration and Nitrogen Fixation in Members of the Unicellular Diazotrophic Cyanobacterial Genus Cyanothece ” Plant Physiology Epub ahead of print, 2012DEC28.
Saha R, Verseput AT, Berla BM, Mueller TJ, Pakrasi HB, Maranas CD (2012) “Reconstruction and Comparison of the Metabolic Potential of Cyanobacteria Cyanothece sp. ATCC 51142 and Synechocystis sp. PCC 6803”, PloS ONE 7(10):e48285.
Aryal UK, Stockel J, Krovvidi R, Gritsenko MA, Monroe ME, Moore RJ, Koppenaal DW, Smith RD, Pakrasi HB, Jacobs JM (2011) “Dynamic proteomic profiling of a unicellular cyanobacterium Cyanothece ATCC51142 across light-dark diurnal cycles”, BMC Syst Biol , 5(1):194.
Aryal UK, Stöckel J, Welsh EA, Gritsenko MA, Nicora CD, Koppenaal DW, Smith RD, Pakrasi HB, Jacobs JM (2011) “Dynamic Proteome Analysis of Cyanothece sp. ATCC 51142 under Constant Light”, J Proteome Res , 2011 Dec 1. [Epub ahead of print].
Bandyopadhyay A, Elvitigala T, Welsh E, Stöckel J, Liberton M, Min H, Sherman LA, Pakrasi HB (2011) “Novel metabolic attributes of the genus cyanothece, comprising a group of unicellular nitrogen-fixing cyanobacteria”, MBio , 2(5). doi: 10.1128/mBio.00214-11.
McDermott JE, Oehmen CS, McCue LA, Hill E, Choi DM, Stöckel J, Liberton M, Pakrasi HB, Sherman LA (2011) “A model of cyclic transcriptomic behavior in the cyanobacterium Cyanothece sp. ATCC 51142”, Mol Biosyst , 7(8):2407-18.
Liberton M, Austin JR 2nd, Berg RH, Pakrasi HB (2011) “Insights into the complex 3-D architecture of thylakoid membranes in unicellular cyanobacterium Cyanothece sp. ATCC 51142”, Plant Signal Behav , 6(4):566-9.
Stöckel J, Jacobs JM, Elvitigala TR, Liberton M, Welsh EA, Polpitiya AD, Gritsenko MA, Nicora CD, Koppenaal DW, Smith RD, Pakrasi HB (2011) “Diurnal rhythms result in significant changes in the cellular protein complement in the cyanobacterium Cyanothece 51142” PLoS One 6(2):e16680.
Liberton M, Austin JR 2nd, Berg RH, Pakrasi HB (2011) “Unique thylakoid membrane architecture of a unicellular N2-fixing cyanobacterium revealed by electron tomography”, Plant Physiol , 155(4):1656-66.
Feng X, Bandyopadhyay A, Berla B, Page L, Wu B, Pakrasi HB, Tang YJ (2010) “mixotrophic and photoheterotrophic metabolism in Cyanothece sp. PCC 51142 under continuous light”, Microbiology 156(8):2566-2574.
Elvitigala T.R., Stöckel j., Ghosh B.K. and Pakrasi H.B. (2009) Effect of continuous light on diurnal rhythms in Cyanothece sp. ATCC 51142, BMC Genomics, 10:226
Elvitigala, T., Pakrasi, H.B. and Ghosh, B.K. (2009) Dynamic Network Modeling of Diurnal Genes in Cyanobacteria, In Emergent Problems in Nonlinear Systems and Control, Springer, 393: 21-41.
