Relieving photosynthesis bottleneck may have a major impact on food crops

An international research team including scientists from the University of Essex have found how to relieve a bottleneck in the process by which plants transform sunlight into food.

They discovered that producing more of a protein that controls the rate in which electrons flow during photosynthesis accelerates the whole process, which may lead to an increase in crop production.

“We tested the effect of increasing the production of the Rieske FeS protein, and found it increases photosynthesis by ten per cent,” said lead researcher Dr Maria Ermakova, from the ARC Centre of Excellence for Translational Photosynthesis (CoETP) in Australia.

“The Rieske FeS protein belongs to a complex which is like a hose through which electrons flow, so the energy can be used by the carbon engine of the plant. By overexpressing this protein, we have discovered how to release the pressure of the hose, so more electrons can flow, accelerating the photosynthetic process,” said Dr Ermakova, who works at The Australian National University (ANU) Centre Node.

The research, published in the journal Communications Biology, is the first time scientists have generated more of the Rieske FeS protein inside C4 plants. Until now, the majority of efforts to improve photosynthesis have been done in species that use C3 photosynthesis, such as wheat and rice. This is despite the fact that C4 crop species - like maize and sorghum - play a key role in world agriculture, and are already some of the most productive crops in the world.

The research is the result of an international collaboration with researchers from Essex, who are part of the Realizing Increased Photosynthetic Efficiency (RIPE) project.

“This is a great example that we need international collaborations to solve the complex challenges faced in trying to improve crop production,” said University of Essex researcher Patricia Lopez-Calcagno, from the School of Life Sciences, who was involved in producing some of the essential genetic components for the plant transformation.

“In the last 30 years, we have learnt a lot about how C4 plants work by making them worse - by breaking them as part of the process of discovery. However, this is the first example in which we have actually improved the plants,” said Professor Robert Furbank, Director of the ARC Centre of Excellence for Translational Photosynthesis and one of the authors of the study.

“Our next steps are to assemble the whole protein FeS complex, which has many other components. There is a lot more to do and lots of things about this protein complex we still don’t understand. We have reached ten per cent enhancement by overexpressing the Rieske FeS component, but we know we can do better than that,” he added.

This research was funded by the ARC Centre of Excellence for Translational Photosynthesis, which aims to improve the process of photosynthesis to increase the production of major food crops such as sorghum, wheat and rice.