Rubisco substitutions predicted to enhance crop performance through carbon uptake modelling

Area of Science:

• Agricultural Science
• Plant Physiology
• Biotechnology

Background:

• Improving crop yields is crucial for global food security.
• The enzyme Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase) is key to carbon fixation in plants.
• Enhancing Rubisco performance is a target for increasing photosynthetic efficiency.

Purpose of the Study:

• To model the impact of bioengineering foreign Rubisco enzymes into C3 and C4 crops.
• To quantify potential improvements in crop carbon uptake under field conditions.
• To identify specific Rubisco enzymes with high potential for crop enhancement.

Main Methods:

• Utilized Earth System Model (ESM) representations of canopy photosynthesis (C3 and C4).
• Integrated species-specific Rubisco kinetic parameters (Kcat, Kc21%O2, Sc/o, Ha).
• Employed a 'two big leaf' model for canopy photosynthesis and analyzed Ameriflux/Fluxnet data.

Main Results:

• Rubisco kinetic variations significantly altered modelled carbon uptake rates.
• Rubiscos from C4 grasses demonstrated the highest potential for improvement.
• Over 50% carbon uptake increase predicted for wheat, and >25% for sugar beet and maize.

Conclusions:

• Bioengineering foreign Rubiscos, particularly from C4 grasses, offers substantial potential for improving crop carbon fixation.
• Further research requires more characterized Rubisco data and improved ESM parameterization for Vcmax and Jmax temperature responses.