The team said the enzyme increased productivity by optimizing photosynthesis.
Using genetic modification, the crop’s inherent Rubisco enzyme (which is responsible for converting carbon dioxide (CO2) into sugars during photosynthesis) is replaced with the more efficient cyanobacterial Rubisco enzyme found in algae.
Trials had begun on tobacco plants, but Professor Martin Parry said the method could ultimately be used to ‘turbo-charge’ photosynthesis in plant crops like wheat.
“Wheat yields in the UK in recent years have reached a plateau. In order to increase yields in a sustainable manner in the future, we need to look at a variety of approaches that include changes within the plant as well as in terms of the surrounding environment of the plant,” he told Milling & Grains.
Fast and furious: Boosting yields and reducing fertilizers
The cyanobacterial enzyme in blue-green algae was faster and more efficient at harnessing sugar and energy for photosynthesis and requires less CO2 than Rubisco found in crop plants, Parry said.
“Rubisco is the key CO2 fixing enzyme in photosynthesis but different types of plant vary in their catalytic properties. Algal Rubiscos and Rubiscos from wild plants occurring in drought environments have catalytic rates and specificities that are predicted to improve photosynthetic capacity in plant crops.”
The team at Rothamsted had demonstrated that plant crops could carry out photosynthesis using the faster cyanobacterial enzyme, with the potential to not only boost crop yields but also reduce fertilisers.
“We are truly excited about the findings of this study. Rubisco accounts for around 25% of leaf Nitrogen (N) so an enzyme that was twice as quick could allow N fertiliser amounts to be decreased by over 10%.”
The scientists utilized a process called ‘homologous recombination’ to connect the bacterial DNA to plant DNA and initiate the production of bacterial proteins in the plant chloroplasts, Parry explained.
“We have generated a synthetic version of this enzyme, which encodes the cyanobacterial enzyme but incorporates combinations of the genetic coding sequence which are more commonly used by ‘higher’ (land) plants.”
The next stage is to combine the ‘faster’ enzyme with a ‘cyanobacterial carbon concentrating mechanism’ (to increase CO2 concentrations for Rubisco) to enable future work on wheat crops, said Parry.
“Changing the chloroplast DNA is a big challenge in most species and is currently not possible for any cereal crop, however if successful it would have major implications for Nitrogen (N) use and sustainability.”