Scientists have discovered a protein that allows algae to efficiently use carbon dioxide; this might help us boost crop yields in the future. The paper is published in Proceedings of the National Academy of Sciences.
Algae being specially efficient at fixing carbon dioxide to synthesise nutrients, researchers want to transfer this trait of theirs to crops to boost agriculture. This would mean crops would be grown in less time than it usually takes while using less water and fertiliser.
To be able to do this, the researchers started by identifying a protein in green algae that is behind this phenomenal efficiency. The team, led by Martin Jonikas, believe this constitutes a critical step that might hopefully pave the way to harnessing the ability of algae.
But, first, let us find out the reason behind algae’s success. To fix carbon dioxide – that is, turn them into sugars – photosynthetic organisms use the enzyme known as rubisco. Life on earth actually depends on this enzyme – this is how we get our food from plants. Rubisco works at a relatively slow pace because carbon dioxide makes up only 0.04% of molecules in our air. This was not always the case, say scientists; according to the latter, rubisco has been around for millions of years, back when the Earth’s atmosphere was rich in carbon dioxide. At that time, rubisco in photosynthetic bacteria was able to work fast, and thus, it sucked up most of the carbon dioxide – its own success would have ultimately deprived it of its efficiency. So, now that we have only traces of carbon dioxide in the air, rubisco’s activity is limited, leading to a restricted crop growth rate. However, algae have a way to counter this limitation.
Algae have a compartment in their cell called the pyrenoid. It is filled with rubisco: it is meant to concentrate carbon dioxide to rubisco so that the enzyme can work faster. Scientists believe that about 33% of the global carbon fixation is happening inside pyrenoids. Now, how to reproduce the pyrenoid into crops? If this cell compartment is incorporated into plant cells, yields might increase by around 60%, say scientists. To get to the bottom of this, the scientists of the new study attempted to understand as to how can rubisco cluster at the pyrenoid.
Their study findings show that a protein known as EPYC1 (Essential Pyrenoid Component 1) is responsible for this clustering. EPYC1 would bind with rubisco and package it into the proteins found inside the pyrenoid. Proteins that are similar to it are present in the majority of algae containing pyrenoids, while those algae not bearing this cell compartment do not have these proteins. EPYC1 might thus be a key element in trying to reproduce the rubisco-efficiency of algae in plants. Jonikas says that their study is the first step to engineer “algal carbon-capture efficiency into crops”.