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Relieving Bottleneck in Photosynthesis May Have a Major Impact on Food Crops

Scientists have found how to relieve a bottleneck in the process by which plants transform sunlight into food, which may lead to an increase in crop production. They discovered that producing more of a protein that controls the rate in which electrons flow during photosynthesis, accelerates the whole process.

Published in the journal Communications Biology the paper demonstrates for the first time that scientists are able to generate more Rieske FeS protein, used in plants to photosynthesize to increase C4 photosynthesis.

“We tested the effect of increasing the production of the Rieske FeS protein, and found it increases photosynthesis by 10 percent,” said lead researcher Dr Maria Ermakova from the ARC Centre of Excellence for Translational Photosynthesis (CoETP).

“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.

Until now, the majority of efforts to improve photosynthesis have been done in species that use C3 photosynthesis, such as wheat and rice, but not a lot has been done in enhancing C4 photosynthesis.

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 Rieske protein is particularly important in environments with high radiance, where C4 plants grow. Previous research has shown that overexpressing the Rieske protein in C3 plants improves photosynthesis, but more research was needed in C4 plants.

The research is the result of an international collaboration with researchers from the University of Essex in the UK, 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, who was involved in producing some of the essential genetic components for the plant transformation.

“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 10 percent enhancement by overexpressing the Rieske FeS component, but we know we can do better than that,” says Professor Furbank, Director of the ARC Centre of Excellence for Translational Photosynthesis and one of the authors of the study. [APBN]

Source: Maria Ermakova, Patricia E. Lopez-Calcagno, Christine A. Raines, Robert T. Furbank & Susanne von Caemmerer (2019) Overexpression of the Rieske FeS protein of the Cytochrome b6f complex increases C4 photosynthesis in Setaria viridis. Communications Biology volume 2, Article number: 314 (2019)