About Crassulacean Acid Metabolism

CAM diagram Crassulacean acid metabolism (CAM) is a photosynthetic CO2 fixation pathway that maximizes water use efficiency (WUE) many times relative to C3 species by using a temporal CO2 pump. Thus, CAM provides an excellent opportunity to engineer both enhanced photosynthetic performance and WUE into bioenergy crops. The proposed research will provide a comprehensive understanding of the enzymatic and regulatory pathways required to engineer CAM photosynthetic machinery into Populus. The methods employed will include deep transcriptome sequencing (RNA-Seq) and high-throughput metabolic profiling of leaf mesophyll cells and stomatal guard cells to identify regulators of the nocturnal opening and daytime closure of stomata that underpins the high WUE of CAM plants in order to create co-expression models. Additional deep genome sequencing combined with chromatin-immunoprecipitation (ChIP-Seq) experiments will be conducted to characterize the transcriptional regulatory networks needed for the circadian clock regulation of CAM. Once characterized, metabolic pathway components of 'carboxylation' and 'decarboxylation' modules will be assembled using an iterative cloning system, and CAM modules will be assembled singly and in combination into a predefined single locus of the target plant genome. Modules will be expressed under the control of circadian clock controlled, drought-inducible promoters in both the readily transformable model Arabidopsis and the important bioenergy crop Populus to promote maximal productivity. Resulting plants will be tested under both control and drought stress conditions for transgene expression, biochemical signatures of CAM, CO2 assimilation, stomatal conductance and transpiration rates, leaf carbon balance, level/mode of CAM activity, biomass productivity and quality, and integrated WUE.

Follow CAMBioDesign on CAMBioDesign


  • 27 June 2017The journal Laboratory Equipment talked with John Cushman and highlights the CAM Biodesign project in a brief article entitled "CAM Plants: Food of the Future." View Website source Laboratory Equipment
  • 05 June 2017The Desert Botanical Garden has announced the "Biology of CAM Plants Conference" to be held April 9, 2018 - April 13, 2018. Organizers include Alberto Búrquez, John Cushman, Sarah Davis, Kevin Hultine, Raul Puente, Ryan Stewart and David G. Williams View Website source Desert Botanical Garden
  • 02 Nov 2016The DOE Joint Genome Institute Community Science Program Allocations for 2017 include CAM species: the establishment of ice plant as a new flagship genome, Kalanchoë laxiflora to inform Gene Atlas, and CAM and C3 Yucca spp. genome sequencing projects initiated. Link to the Article source jgi.doe.gov
  • 02 Nov 2015The pineapple genome and the evolution of CAM photosynthesis. Link to the Article source palgrave.nature.com
  • 13 Jul 2015Does Agave Hold the Secret to Drought-Resistant Farming? Link to the Article source scientificamerican.com
  • 22 June 2015Society of Chemical Industry, Issue June 2015; "CAM do Biofuels" publication of arcticle. Link to the Article source soci.org
  • 01 May 2015International Innovation, Issue 172; "The Biodesigner" publication of arcticle. Download Article source internationalinnovation.com


  • Abraham PE, Yin H, Borland AM, Weighill D,Lim SD, De Paoli HC, Engle N, Agh R, Weston DJ, Wullschleger SD, Tschaplinski T, Jacobson D, Cushman JC, Hettich RL, Tuskan GA, Yang X. Transcript, protein and metabolite temporal dynamics in the CAM plant Agave. Nature Plants. 2:16178 (21 November 2016). doi:10.1038/nplants.2016.178.
  • Chiang C-P, Yim WC, Sun Y-H, Ohnishi M, Mimura T, Cushman JC, Yen HE. (2016) Identification of ice plant (Mesembryanthemum crystallinum L.) microRNAs using RNA-Seq and analysis of their potential functional roles in high salinity responses in seedlings. Frontiers in Plant Science (09 August 2016). doi:10.3389/fpls.2016.01143.
  • Petereit J, Smith S, Harris FC, Schlauch KA (2016). petal: Co-expression network modelling in R. BMC Systems Biology Vol 10 Suppl 2 (1 August 2016). doi:10.1186/s12918-016-0298-8.
  • Hartwell J, Dever LV, Boxall SF (2016). Emerging model systems for functional genomics analysis of crassulacean acid metabolism. Current Opinion in Plant Biology 31:100-108. doi:10.1016/j.pbi.2016.03.019.
  • Borland AM, Guo H-B, Yang X, Cushman JC (2016). Orchestration of carbohydrate processing for crassulacean acid metabolism. Current Opinion in Plant Biology 31:118. doi:10.1016/j.pbi.2016.04.001.
  • Liu D, Hu R, Palla KJ, Tuskan GA, Yang X (2016). Advances and perspectives on the use of CRISPR/Cas9 systems in plant genomics research.Current Opinion in Plant Biology 30:70. doi:10.1016/j.pbi.2016.01.007.
  • Czarnecki O, Bryan AC, Jawdy SS, Yang X, Cheng Z-M, Chen J-G, Tuskan GA (2016). Simultaneous knockdown of six non-family genes using a single synthetic RNAi fragment in Arabidopsis thaliana. Plant Methods 12:16. doi:10.1186/s13007-016-0116-8.
  • De Paoli HC, Tuskan GA, Yang X (2016). An innovative platform for quick and flexible joining of assorted DNA fragments. Scientific Reports 6:19278. doi:10.1038/srep19278.
  • Petereit J, Harris FC, Schlauch K (2015). petal: A novel co-expression network modeling system. Bioinformatics and Biomedicine (BIBM), 2015 IEEE International Conference Proceedings: pp. 234-241. doi:10.1109/BIBM.2015.7359686.
  • Ming R, Van Buren R, Wai CM, Tang H, Schatz MC, Bowers, JE, Lyons E, Wang M-L, Chen J, Biggers E, Zhang J, Huang L, Zhang L, Miao W, Zhang J, Ye Z, Miao C, Lin Z, Wang H, Zhou H, Yim WC, Priest HD, Zheng C, Woodhouse M, Edger PP, Guyot R, Guo H-B, Guo H, Zheng G, Singh R, Sharma A, Min X, Zheng Y, Lee H, Gurtowski J, Sedlazeck F, Harkess A, McKain MR, Liao Z, Fang J, Liu J, Zhang X, Zhang Q, Hu W, Yuan Q, Wang K, Chen L-Y, Shirley N, Lin Y-R, Liu L-Y, Hernandez AG, Wright CL, Bulone V, Tuskan GA, Heath K, Zee F, Moore PH, Sunkar R, Leebens-Mack JH, Mockler T, Bennetzen JL, Freeling M, Sankoff D, Paterson AH, Zhu X, Yang X, Smith, JAC, Cushman JC, Paull RE, Yu, Q (2015). The pineapple genome and the evolution of CAM photosynthesis.Nature Genetics 47:1435. doi:10.1038/ng.3435.
  • Yang L, Carl S, Lu M, Mayer JA, Cushman JC, Tian E, Lin H (2015). Biomass characterization of Agave and Opuntia as potential biofuel feedstocks. Biomass and Bioenergy 76: 43-53. doi:10.1016/j.biombioe.2015.03.004.
  • Yang X, Leebens-Mack J, Chen F, and Yin Y (2015). Plant Comparative and Functional Genomics. International Journal of Genomics, vol. 2015, Article ID 924369. doi:10.1155/2015/924369.
  • Yao J, Guo H, Yang X. PPCM: Combing multiple classifiers to improve protein-protein interaction prediction (2015). International J Genomics. Article ID 608042. doi:10.1155/2015/608042.
  • Borland AM, Wullschleger SD, Weston DJ, Tuskan GA, Hartwell J, Yang X, Cushman JC (2015). Climate-resilient agroforestry: Physiological responses to climate change and engineering of crassulacean acid metabolism (CAM) as a mitigation strategy. Plant Cell & Environ. 38:1833-1849. doi:10.1111/pce.12479.
  • Yang X, Cushman JC, Borland AM, Erika J. Edwards EJ, Wullschleger SD, Tuskan GA, Owen NA, Griffiths H, Smith JAC, De Paoli HC, Weston DJ, Robert Cottingham R, Hartwell J, Davis SC, Silvera K, Ming R, Schlauch KA, Abraham P, Stewart JR, Guo H-B, Albion RA, Ha J, Lim SD, Wone BWM, Yim WC, Garcia T, Mayer JA, Petereit J, Nair SS, Casey E, Hettich RL, Ceusters J, Ranjan P, Palla KJ, Hengfu Yin H, Reyes-García C, Andrade JL, Freschi L, Beltran JD, Dever LV, Boxall SF, Waller J, Davies J, Bupphada P, Kadu N, Winter K, Rowan F. Sage RF, Aguilar CN, Schmutz J, Jenkins J, Holtum, JAC (2015). A roadmap for research on crassulacean acid metabolism to enhance sustainable food and bioenergy production in a hotter, drier world. New Phytologist 207:491-504. doi:10.1111/nph.13393 .
  • Cushman JC, Davis SC, Yang X, Borland AM (2015). Development and use of bioenergy feedstocks for semi-arid and arid lands. J. Exp. Bot. 66: 4177-4193. doi:10.1093/jxb/erv087.
  • Dever LV, Boxall SF, Knerova J, Hartwell J (2015). Transgenic perturbation of the decarboxylation phase of crassulacean acid metabolism alters physiology and metabolism but only has a small effect on growth. Plant Physiol. 167:44-59. doi:10.1104/pp.114.251827.
  • Silvera K, Winter K, Rodgriguez BL, Albion, RL, Cushman JC (2014). Multiple isoforms of phophoenolpyruvate carboxylase in the Orchidacea (subtribe Oncidiinae): implications for the evolution of crassulacean acid metabolism. J. Exp. Bot. 65 (13):3623-3636. doi:10.1093/jxb/eru234.
  • Ceusters J, Borland AM, Taybi T, Godts C, Lembrechts, Calcoen J, De Proft MP (2014). Light quality modulates metabolic synchronization over the diel phases of crassulacean acid metabolism. J. Exp. Bot. 65 (13): 3705-3714. doi:10.1093/jxb/eru185.
  • Cushman JC (2014). Interview with John C. Cushman. Trends Plant Sci. 19(5):274-275. doi:10.1016/j.tplants.2014.03.003.
  • DePaoli HC, Borland AM, Tuskan GA, Cushman JC, Yang X (2014). Synthetic biology as it relates to CAM photosynthesis: Challenges and opportunities. J. Exp. Bot. 65:3381-3393. doi: 10.1093/jxb/eru038.
  • Yin H, Chen CJ, Yang J, Weston DJ, Chen JG, Muchero W, Ye N, Tschaplinski TJ, Wullschleger SD, Cheng ZM, Tuskan GA, Yang X (2014). FUNCTIONAL GENOMICS OF DROUGHT TOLERANCE IN BIOENERGY CROPS. CRITICAL REVIEWS IN PLANT SCIENCES 33:205-224. doi:: 10.1080/07352689.2014.870417.
  • Borland AM, Hartwell J, Weston DJ, Schlauch KA, Tschaplinski TJ, Tuskan GA, Yang X, Cushman JC (2014). Engineering crassulacean acid metabolism to improve water-use efficiency. Trends Plant Sci. 2014 Feb 19. pii: S1360-1385(14)00021-1. doi:10.1016/j.tplants.2014.01.006.
  • Zambrano VAB, Lawson T, Olmos E, Fernández-Garcia N, Borland AM (2014). Leaf anatomical traits which accomodate the facultative engagement of crassulacean acid metabolism in tropical trees of the genus Clusia. J.Exp.Bot. First published online Feb 7, 2014 doi:10.1093/jxb/eru022.
  • Borland AM, Yang X (2013). Informing the improvement and biodesign of crassulacean acid metabolism via system dynamics modelling. New Phytologist 200(4):946–949. doi:10.1111/nph.12529.

Back to top


April 9-13, 2018 Biology of CAM Plants Conference. Desert Botanical Garden, Phoenix, AZ. Registration will be available in September 2017. View Website.

February 6-8, 2017 Genomic Science Contractors– Grantees Meeting and USDA-DOE Plant Feedstock Genomics for Bioenergy Meeting XV. The CAM Biodesign Project was represented by two posters. View Abstracts.

January 14-18, 2017 Plant & Animal Genome XXV: The meeting was held at the Town & Country Hotel, San Diego, CA, USA. John Cushman co-chaired a workshop on "Functional Genomics of C4 and CAM Photosynthesis." View Program.

March 6-9, 2016 Genomic Science Contractors– Grantees Meeting and USDA-DOE Plant Feedstock Genomics for Bioenergy Meeting XIV. The project was represented by five posters. View Abstracts.

January 8-13, 2016 Plant & Animal Genome XXIV: The meeting was held at the Town & Country Hotel, San Diego, CA, USA. The CAM Biodesign project was represented by four oral presentations, five posters and a workshop. Search Abstracts.

February 22-25, 2015 DOE awardee meeting: The meeting was held at the Bethesda North Marriott Hotel and Conference Center. The project was represented by three posters. View program.

January 10-14, 2015 Plant & Animal Genome XXIII: The meeting was held at the Town & Country Hotel, San Diego, CA, USA. This project was represented by oral presentations by Paul Abraham, Jerry Jenkins and Won Yim, as well as five posters. Search Abstracts.

July 15-18, 2014 -34th New Phytologist Symposium: CAMBioDesign researchers will be participating in the event Event Link

February 10-12, 2014 DOE awardee meeting: The meeting was held February at the Bethesda North Marriott Hotel and Conference Center. John Cushman presented at this event and the project was represented by three posters. View program.

February 24-27, 2013 DOE awardee meeting: The meeting was held February 24th-27th at the Bethesda North Marriott Hotel and Conference Center. John Cushman presented at this event. View program.

August 6-9, 2013 - Annual meeting 2013: C4/CAM meeting was held in U. of Illinois Campus Conf. Center, Aug. 6-9, 2013; A conference room of our CAM satellite Meeting Aug. 6; C4 Rice Eng. Meeting on Aug. 10). View Flyer

Publication Highlights

    November 21, 2016

    April 19, 2016

    April 12, 2016

    February 18, 2016

    February 17, 2016

    January 13, 2016

    July 7, 2015

    March 11, 2014

    February 24, 2014

    February 19, 2014

    February 7, 2014

Back to top

Position Openings

Post-Doctoral Research Associate Oak Ridge National Laboratory. Plant Systems Biology and Synthetic Biology. The Plant Systems Biology group is seeking a postdoctoral researcher with experience in plant synthetic biology, genome editing, molecular biology, molecular genetics, and biochemistry. For more information contact Xiaohan Yang, yangx@ornl.gov. Posted: August 7, 2016