Rubisco substitutions predicted to enhance crop performance through carbon uptake modelling.

ABSTRACT: Improving the performance of the CO2-fixing enzyme Rubisco is among targets for increasing crop yields. Here, Earth system model (ESM) representations of canopy C3 and C4 photosynthesis were combined with species-specific Rubisco parameters to quantify the consequences of bioengineering foreign Rubiscos into C3 and C4 crops under field conditions. The "two big leaf" (sunlit/shaded) model for canopy photosynthesis was used together with species-specific Rubisco kinetics parameters including maximum rate (Kcat), Michaelis-Menten constant for CO2 at ambient atmospheric O2 (Kc 21%O2), specificity for CO2 to O2 (Sc/o), and associated heat activation (Ha) values. Canopy scale consequences of replacing native Rubiscos in wheat, maize and sugar beet with foreign enzymes from 27 species were modelled using data from Ameriflux and Fluxnet databases. Variation among the included Rubisco kinetics differentially affected modelled carbon uptake rates, and Rubiscos from several species of C4 grasses showed the greatest potential of over 50% carbon uptake improvement in wheat, and over 25% improvement in sugar beet and maize. This study also reaffirms the need for data on fully characterized Rubiscos from more species, and for better parameterisation of 'Vcmax' and temperature response of 'Jmax' in ESMs.

SUBMITTER: Iqbal WA 

PROVIDER: S-EPMC8411856 | biostudies-literature |

REPOSITORIES: biostudies-literature