Rubisco Catalytic Properties and Temperature Response in Crops

Area of Science:

• Plant Physiology
• Biochemistry
• Crop Science

Background:

• Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) enzyme kinetics and their temperature dependence are critical factors limiting plant CO2 assimilation.
• Significant variations in Rubisco's catalytic traits and thermal sensitivity exist across different plant species.

Purpose of the Study:

• To characterize Rubisco kinetics across 20 crop species at three temperatures.
• To investigate the interspecific variation in Rubisco's thermal sensitivity and kinetic parameters.
• To explore the relationship between Rubisco sequence evolution and kinetic traits.

Main Methods:

• Enzyme kinetic assays were performed on Rubisco from 20 crop species at varying temperatures.
• Analysis of Rubisco large subunit sequences was conducted to identify sites under adaptive evolution.
• CO2 assimilation potential was evaluated under different temperature and CO2 concentration scenarios.

Main Results:

• Confirmed significant interspecific variation in Rubisco kinetics, with differences influenced by specific kinetic parameters.
• Observed varying thermal sensitivities among species, with parameters like Rubisco Km for CO2 showing higher activation energy.
• Identified specific amino acid sites under adaptive evolution linked to distinct Rubisco kinetic traits.
• Demonstrated that species-specific Rubisco kinetics significantly impact CO2 assimilation potential, particularly under high temperatures and low CO2.

Conclusions:

• Rubisco's catalytic traits and temperature responses are species-specific, influencing crop CO2 assimilation.
• This species-specific variation has implications for crop performance under changing environmental conditions.
• Findings offer valuable insights for improving photosynthesis models and engineering more efficient Rubisco enzymes for enhanced crop productivity.