Photosynthesis has evolved over millions of years - so is it possible for scientists to improve on it? Teams of scientists from a range of different disciplines from both the US and the UK are working to make photosynthesis more efficient.
Professor Janet Allen, Director of Research at BBSRC, said "Photosynthesis has evolved in plants, algae and some other bacteria and in each case the mechanism does the best possible job for the organism in question. However, there are trade-offs in nature which mean that photosynthesis is not as efficient as it could be - for many important crops such as wheat, barley, potatoes and sugar beet, the theoretical maximum is only 5%, depending on how it is measured. There is scope to improve it for processes useful to us, for example increasing the amount of food crop or energy biomass a plant can produce from the same amount of sunlight. This is hugely ambitious research but if the scientists we are supporting can achieve their aims it will be a profound achievement."
Some of the scientists will be focusing improving the efficiency of the 'bottleneck' enzyme RuBisCO. By attempting to transfer parts from algae and bacteria into plants, the researchers hope to make the environment in the plants' cells around RuBisCO richer in carbon dioxide which will allow photosynthesis to produce sugars more efficiently.
The CAPP team explains
"In most plants, growth rate is limited by the rate at which carbon dioxide from the atmosphere is taken up and converted to sugars in the process of photosynthesis. The enzyme responsible for the first step in this process, Rubisco, does not work at its potential maximum efficiency at the current levels of carbon dioxide present in the atmosphere. If levels were much higher, photosynthesis would be faster and plants would grow faster. This speeding-up of photosynthesis will happen naturally over the next fifty years or so as atmospheric carbon dioxide levels rise due to human activities. However, there is an immediate requirement for increased crop productivity to provide food for the rising population of the planet. Our project addresses this problem. We are studying a mechanism present in tiny green algae that results in high concentrations of carbon dioxide inside their photosynthesising cells (called a Carbon Concentrating Mechanism, or CCM), enabling Rubisco to work at maximum efficiency. We have recently discovered important new information about this mechanism, and we have invented new and rapid methods to discover algal genes that contribute to it. We have two complementary and parallel aims. First, we will apply our new methods to identify all of the genes required by the algae to achieve high concentrations of carbon dioxide inside the cells, and we will discover exactly how these genes work. Second, we will transfer the most important genes into a plant, and study whether the same CCM can be recreated inside a leaf. If it can, we expect that our experimental plant will have higher rates of photosynthesis and hence a higher rate of growth than normal plants. This work will provide new insights into how plants and algae acquire and use carbon dioxide from the atmosphere, of great importance in predicting and coping with the current rapid changes in the atmosphere and hence in climate. The work will also contribute to strategies to increase global food security, because it will indicate new ways in which crop productivity can be increased."
See their website at: http://mudshark.brookes.ac.uk/CAPP