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Beyond photorespiration: A systematic approach to unlocking enhanced plant productivity

A study in Science Advances has revealed promising strategies to significantly improve crop yields by addressing photorespiration, a metabolic process that can reduce productivity by up to 36% in some crops. Researchers from the University of Groningen and Heinrich Heine University Düsseldorf, working as part of the GAIN4CROPS project, have evaluated several alternative pathways that could help overcome this major agricultural bottleneck.

Photorespiration occurs when the enzyme RuBisCO, essential for photosynthesis, reacts with oxygen instead of carbon dioxide, resulting in substantial losses of fixed carbon and energy. This inefficiency costs the global agricultural sector billions in lost crop productivity annually.

"Our work shows that overcoming photorespiration through engineered pathways can provide a dual benefit: increasing carbon fixation while reducing energy losses," said Prof. Heinemann from the University of Groningen. "This has significant implications for the development of crops that are not only more productive but also better adapted to the changing climate and growing global food demands."

The study employed advanced mathematical models to analyze twelve alternative pathways designed to bypass or optimize photorespiration. The researchers classified these pathways based on their carbon-fixing abilities and identified which approaches offer the greatest potential improvements in different environmental conditions.

Key findings include:

• Carbon-fixing alternative pathways showed the most promise, offering up to 20% more carbon export compared to conventional photorespiration
• The TaCo pathway, developed in another project called FutureAgriculture and now used in projects such as GAIN4CROPS and CROP4CLIMA, demonstrated substantial potential for yield improvement
• Environmental factors such as light intensity and CO₂ availability significantly influence the effectiveness of different pathways
• Carbon-fixing pathways achieve optimal productivity under both high light and CO₂-limited conditions

The research also provides new insights that could help explain previous experimental observations and guide future efforts to engineer crops with reduced photorespiration losses.

"With the ability to more rationally engineer alternative photorespiratory pathways into suitable crops and identify their optimal growing conditions, our work will hopefully contribute to realizing the maximum impact of alternative photorespiratory pathways for improving crop yields," noted Prof. Weber, coordinator of the GAIN4CROPS project from the Heinrich Heine University Düsseldorf.

Next steps include further optimization of the alternative pathways and application to crops with the greatest potential for yield improvement. These advancements could play a crucial role in addressing global challenges such as food security and climate change adaptation.