Photosynthesis is one of evolution's great success stories. Plants, algae and bacteria capture light energy from the sun and transform it into chemical energy.
Can science improve it? Perhaps. While genetic modification is protested by anti-science groups, no one dislikes photosynthesis. And improving the photosynthetic rate is one strategy to improve plant productivity, which can be important for future food production.
Scientists have used synthetic biology approaches to demonstrate for the first time that micro-compartments made up of proteins originating in bacteria can be assembled in the chloroplasts of flowering plants. Assembling a compartment inside chloroplasts of flowering plants has the potential to improve the efficiency of photosynthesis.
Plants could be made more efficient at fixing carbon dioxide from the air into molecules that can be used by the plant for growth.
Nicotiana benthamiana is a model plant species related to tobacco and routinely used in research. Cyanobacteria have a natural CO2 concentration mechanism that is encapsulated in microcompartments called the carboxysome.
Green Microcompartments in Red Chloroplasts. Credit: Rothamsted Research
Dr. Alessandro Occhialini, Rothamsted Research scientist, says, "I was thrilled to see small round or oval bodies in chloroplasts several days after I infiltrated bacterial genes into the leaves."
In order to engineer the bacterial genes to work properly in plants, postdoctoral fellow Dr. Myat Lin at Cornell used recombinant DNA methods to connect the bacterial DNA to plant DNA sequences so that several bacterial proteins could be produced simultaneously in chloroplasts and spontaneously assemble into small compartments. Lin commented, "Being a part of a project with such a big goal to improve photosynthesis has been tremendously rewarding. While more work is ahead, we certainly have a very promising start."
Professor Maureen Hanson, lead scientist at Cornell University said, "We are delighted with the encouraging results from our collaboration with the Rothamsted Research group, whose expertise in photosynthesis and electron microscopy complements our capabilities in genetic engineering."
Professor Martin Parry, lead scientist at Rothamsted Research, said, "We are truly excited about the findings of this study. Improving photosynthetic rate in crop plants has been scientifically challenging and the developments in the areas of synthetic biology and metabolic engineering enable us to make significant progress. It is important that we explore all available tools to us in order to ensure food and fuel security in the future."
Citation: Myat T. Lin, Alessandro Occhialini, John P. Andralojc, Jean Devonshire, Kevin M. Hines, Martin A. J. Parry, Maureen R. Hanson, 'β-carboxysomal proteins assemble into highly organized structures in Nicotiana chloroplasts', The Plant Journal DOI: 10.1111/tpj.12536
