Crassulacean acid metabolism and tissue succulence are metabolic and anatomical adaptations that improve water-use efficiency and drought (and salinity) stress tolerance in plants. These traits are among the most widespread and successful adaptations in the plant kingdom for mitigating drought stress, and thus, represent highly useful traits for the design of climate-resilient crops. The goal of this project is to test optimized synthetic versions of crassulacean acid metabolism alone and in combination with engineered tissue succulence. The proposed synthetic gene circuits developed by this project can be applied widely to other food, feed, fiber, and biofuel crops to improve their productivity, improve water-use efficiency, and drought/salinity stress tolerance under the hotter and drier environments of the future. The project will also provide training of an increasingly diverse scientific workforce through student recruitment efforts that target students from historically underrepresented groups in science, technology, engineering, and mathematics. In addition, the project will provide training and preparedness of future scientists in evidence-based, visually focused, scientific communication through unique training opportunities for undergraduate and graduate students, and postdoctoral scholars in plant biochemistry, synthetic biology, and biotechnology blended with infographics, interactive visualizations, and visual social media. The investigators will increase public awareness of the need for more climate-resilient crops through the production of two high-quality videos describing the project deliverables to showcase the societal benefit of these biotechnological innovations. Lastly, the training and outreach activities will be evaluated through robust assessment activities to appraise their impact on public science outreach.

Future increases in drought severity and duration will significantly slow the rate of crop productivity increases needed to satisfy future projected crop demands and threaten global food security. Therefore, innovative synthetic biology approaches for curtailing photorespiration and improving water-use efficiency via the introduction of synthetic crassulacean acid metabolism into C3 photosynthesis crops are essential. The proposed research will generate optimized synthetic carboxylation, decarboxylation, starch degradation, and complete crassulacean acid metabolism gene circuits. The resulting plants will be evaluated for improved growth, productivity, water-use efficiency, and water-deficit and salinity tolerance. In addition, plants expressing optimized crassulacean acid metabolism gene circuits will be evaluated with and without engineered tissue succulence in Arabidopsis and soybean, a critically important C3 photosynthesis crop for the U.S.. Empirical testing will be accompanied by detailed, genome-scale transcriptomic and metabolome profiling and diel flux balance analysis modeling to corroborate energetic efficiency predictions for each iteration of the synthetic crassulacean acid metabolism gene circuits. The broader impacts of the project include improving national food, feed, fiber, and biofuel security by enhancing crop productivity, water-use efficiency, and drought/salinity tolerance in a changing environment. Outreach and training goals include ensuring the training of an increasingly diverse scientific workforce through recruitment of underrepresented students, providing training and preparedness of future scientists in scientific communication, increasing public awareness of the need to improve the climate-resiliency of crops using videos describing the concepts of synthetic CAM and engineered tissue succulence, and assessing training, outreach and engagement activities for didactic and societal impacts.

This award was co-funded by the Plant Genome Research Program and the Physiological Mechanisms and Biomechanics Program in the Division of Integrative Organismal Systems.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

National Science Foundation (NSF)
Division of Integrative Organismal Systems (IOS)
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Gerald Schoenknecht
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Board of Regents, Nshe, Obo University of Nevada, Reno
United States
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