Transforming crop yields through synthetic photorespiration
As the global population continues to grow and the availability of arable land reaches capacity, it is important to find new ways of improving food crop productivity. EU-funded researchers are investigating the potential of novel photorespiration pathways to help meet this challenge.
© INSRL, 2017
Across the world today, one in seven people is malnourished and enduring the outcomes of a situation which is expected to worsen as the global population continues to increase. If we are to maintain our natural biodiversity and habitat we cannot continue to expand arable lands.
Furthermore, not all land is suitable for growing crops. This means that we must find new ways to boost the productivity of food crops within the existing space available and in a wide range of conditions, including the growing impact of climate change.
The EU-funded FUTUREAGRICULTURE project is working on a radically different approach centred around the process of photorespiration. Natural plant photorespiration takes up oxygen in the light, dissipates energy produced by photosynthesis and releases carbon dioxide (CO2) back into the atmosphere. This reduces the effective rate of carbon fixation and thereby lowers agricultural productivity.
By designing and engineering plants that can overcome the deficiencies of natural photorespiration, FUTUREAGRICULTURE aims to boost agricultural yield.
One of the main barriers to increasing yield is the low efficiency of carbon fixation the process through which life energy is converted into biomass or sugars. We decided to focus on this process, noting current inefficiencies and also where intervention might be possible, says project coordinator Dr Arren Bar-Even of the Max Planck Institute in Germany.
Creating novel enzymes
Using state-of-the-art synthetic biology tools, the project team set out to design and engineer entirely new CO2-neutral or CO2-positive photorespiration pathways based on novel enzyme chemistry. Using computer simulations, their work demonstrated that certain bypass routes could dramatically boost the agricultural productivity rate potentially by as much as 60 %, and would also be able support higher yields in a wide variety of conditions, such as drought, poor light, etc.
We found five or six pathways which seemed to be very interesting and included known enzymes. But we also discovered new enzymes not yet known to nature but which we have been able to engineer, explains Bar-Even.
In-vitro research is now ongoing to establish the functions of these novel enzymes and pathways in living organisms. Enhanced photosynthetic efficiency will be demonstrated in vivo in cyanobacteria (photosynthetic bacteria living in the soil and water) expressing the synthetic pathways. Finally, the most promising pathways will be implemented in model plants and the growth phenotypes will be monitored.
These new pathways are also expected to perform very well under difficult or challenging conditions because they are much more CO2 efficient. We expect the plants to be more tolerant to the lack of water and they should be able to produce more biomass per unit of land and of time than at present.
FUTUREAGRICULTURE represents a radical breakthrough in research to increase agricultural productivity by systematically exploring new metabolic pathways previously unknown in nature which have a significant potential to revolutionise the way plants grow.