Rubisco's role in food and energy security

As global food and energy demand continues to grow, researchers are exploring multiple strategies to boost crop productivity. While engineering plant enzymes and biochemical pathways that are more efficient remains a transformative goal, this review highlights another promising approach: increasing Rubisco content. Rubisco is the plant enzyme that captures atmospheric CO2 and converts it into organic compounds, essentially making it responsible for plant growth and the production of food through photosynthesis. Increasing Rubisco could complement existing efforts, offering a more immediate way to enhance yields while research on more complex innovations progresses.

"We're interested in optimizing photosynthesis to improve food and energy security," said Coralie Salesse-Smith, a postdoctoral researcher in the Long Lab. "This paper highlights an alternative way to increase photosynthesis by focusing on increasing Rubisco content. We hope this review inspires exciting new research and agricultural applications." 

Salesse-Smith, along with coauthors Steve Long and Yu Wang, recently published a Tansley Review about improving crops via increased Rubisco for New Phytologist. Tansley reviews are invited, in-depth reviews that bring a personal perspective to the presentation of thought-provoking ideas, rather than broad documentation of published literature.

The team’s review specifically explored potential impacts on yield and nitrogen use, building upon their ongoing work for the Center for Advanced Bioengineering and Bioproducts Innovation. Writing the review, which highlighted Rubisco's role in photosynthesis enhancement in an accessible way, leveraged their unique strengths and expertise in molecular biology, plant physiology, and modeling.

"Rubisco is a key limitation to photosynthesis in both C3 and C4 crops, and it's going to continue to be a key limitation," Salesse-Smith emphasized. "Targeting it as an approach to improve photosynthesis has practical value, particularly in the short term."

Environmental factors also play a significant role. Salesse-Smith noted that increasing Rubisco might be particularly helpful under conditions that decrease the concentration of CO2 inside chloroplasts, including drought or heat stress, both of which have increased in recent years due to climate change. Also trending up with climate change are CO2 levels. Improved crops with increased Rubisco may be able to better use this extra carbon for growth.

Increasing Rubisco content can offer benefits sooner than other strategies, but larger improvements will ultimately be required. The path forward may require combining Rubisco modifications with complementary strategies that address specific stressors to maximize effectiveness. By using tools like CRISPR/Cas, researchers can make genetic changes that could be achieved through natural selection or traditional breeding, but in a faster and more directed way. Scientists can fine-tune native genes, not only optimizing Rubisco but also addressing other critical factors such as stress tolerance and resource use efficiency. This integrated strategy creates opportunities to improve plant productivity while aligning with regulatory frameworks and public acceptance.

"Without these innovations, food insecurity will become more pressing in the future," Salesse-Smith said. "It’s important to get improved crop varieties into agricultural fields before it’s too late."

By incorporating the latest research on Rubisco's limitations and potential, the authors emphasize both the short-term gains achievable through increasing Rubisco content and the long-term promise of engineering a more efficient enzyme. Salesse-Smith believes the strategies highlighted in the review article can help meet the growing global food demand.

"Improving photosynthesis is a promising avenue," she said. "I think improving photosynthesis, and Rubisco specifically, will be an important way to cope with food demand in the future.”

Steve Long is the Ikenberry Endowed University Chair of Crop Sciences and Plant Biology at the Carl R. Woese Institute for Genomic Biology located at the University of Illinois, He is the Director of the Realizing Increased Photosynthetic Efficiency project and has affiliations with the College of Agriculture, Consumer, and Environmental Sciences, College of Liberal Arts & Sciences, and the Grainger College of Engineering. Yu Wang is a former postdoctoral researcher in the Long Lab and is currently an Assistant Professor at Nanjing University in China.